Sciencemadness Discussion Board

Azides

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Hennig Brand - 8-8-2011 at 12:00

There is some of Microtek's method in there for sure, and also some of yours. For this experiment I did the freebasing with just a few drops of water and no alcohol until the end, all in an erlenmeyer with a ground glass stopper. It is sort of a combination of Microtek' s method and yours, with a twist.

A book I have been reading states that it is inferior to do the freebasing in alcohol. According to Leonid Lerner
in "Small scale Synthesis of Laboratory Reagents", there is a large amount of insoluble gel produced when freebasing in alcohol because the sulfates are insoluble in alcohol. This insoluble sulfate gel locks in Hyrazine Sulfate, and prevents it from reacting with the hydroxide, which lowers yield. I think in small quantities and with a bit of trituration, the alcohol method is probably ok. In larger scale synthesis no alcohol is definitely best.

In regards to the yield, I wasn't using my best scales so I could be off a percent or two I guess. My scales weighing heavy by 0.05g would lower the yield by about 1.2%, if heavy by 0.1g then the yield would be lower by about 2.5%. I have compared these scales on several occasions to better ones and they were not off more than that.

I just took the mass of the sample again after a day of drying to see if it had lost any more moisture, it hadn't.

Is KOH really the limiting quantity with a 76% yield, if using a stoichiometric quantity? According to the same book as above, I could have gotten a yield of 86% KN3 or 90% NaN3 by this method.

I just went through the stochiometry, and there was about 5% excess of KOH used. I think there may have been some NaOH carry over from the freebasing too (slight excess used there as well). I was using my notes that I used before for the NaOH method, and just increased the amount to adjust for the heavier potassium cation, so I must have used an excess with the NaOH method as well. Now that I am actually looking at the bottle of KOH, it says Potassium Hydroxide Reagent, Assay (KOH) 87.4%, Potassium Carbonate (K2CO3) 0.81%, and a list of other trace contaminants all totaling 88.24%. The balance must be water. The container is well sealed.

I guess I could be off by a certain amount, but I don't think it is more than a couple percent. Thanks for pointing that out, I hadn't thought it all through actually.

I am very happy with this method. It isn't quite as quick or as easy on alcohol as your method, but it is simple and straight forward using only a flask as equipment (a stirrer helps a lot to dissolve the hydroxide in the alcohol though). Potassium Hydroxide might be a little harder to obtain than NaOH for some people.

KOH bottle.JPG - 356kB

BTW, we may need to add a couple more percent to the yield. I kept the reaction liquid after collecting the crop of potassium azide. I just looked now and there is another small amount which has precipitated in the last day or so. If I am going to keep saving it, I have got to stop keeping it in plastic bottles.


[Edited on 8-8-2011 by Hennig Brand]

Hennig Brand - 8-8-2011 at 13:31

Just did a little more reading in "The Book". The KN3 synthesis in the book uses 85% KOH. They added enough KOH, even with corrections for purity, to be in excess of a stoichiometric amount by ~6%. I didn't add enough, if the author is correct. He claims to get a yield of 86% for the KN3 synthesis. The method in the book uses ethanol as the reaction medium though.



[Edited on 8-8-2011 by Hennig Brand]

Rosco Bodine - 8-8-2011 at 13:52

Freebasing of hydrazine hydrate from hydrazine sulfate definitely is an art of careful manipulation of additions, stirring, moisture content, heating, and solvent volume, all being done with due regard for air exposure being minimized because it destroys free hydrazine. Sodium ethoxide in ethanol would probably work well to complete the freebasing after the half neutralization slurry paste of dihydrazine sulfate. There is probably a certain mole scale and optimum sequence which is easiest, for the particular alcohol and base. At medium scale
I use added heating to keep the hydrate slurry from setting up like cement.
I have some teflon stoppered 2 liter Erl's and 4 and 5 inch stirbars which hopefully I can use in the future to try a larger scale freebasing. I have components for some high gauss high torque low speed mag stir hotplates
of a custom variety but haven't had time to put 'em together and try them yet.
Most bench scale lab equipment is way underbuilt for what it costs. To get serious lab equipment that isn't cheaply built crap you either build it yourself or spend many thousands to basically hire it done by the few companies that specialize.

Yeah a few percent excess sounds about right ...not too much, a discrete excess ....it is also a safety against free HN3 which could ruin your whole day.

[Edited on 8-8-2011 by Rosco Bodine]

reference #15 for Carbamoyl Azide article

Rosco Bodine - 9-8-2011 at 20:14

Die Zersetzung des Carbaminsäureazids NH2CO.N3 für sich und in aromatischen Kohlenwasserstoffen
Theodor Curtius, Friedrich Schmidt
Journal für Praktische Chemie
1923, Volume 105, Issue 1, pages 177–198
DOI: 10.1002/prac.19231050115

Attachment: Die Zersetaung dos Carbarninslureadds NH,CO. N8 fir sioh nnd in aromatisohen Kohlenwasserstoffen.pdf (958kB)
This file has been downloaded 633 times

Also attached

Ueber Semicarbazid
Johannes Thiele, Otto Stange
Justus Liebigs Annalen der Chemie
1894, Volume 283, Issue 1-2, pages 1–46
DOI: 10.1002/jlac.18942830102

Attachment: Ueber Semicarbazid.pdf (1.6MB)
This file has been downloaded 559 times

[Edited on 10-8-2011 by Rosco Bodine]

Hennig Brand - 10-8-2011 at 19:30

Thought this might be of interest. It has much detailed information about materials and methods to sensitize Silver Azide. It also discusses ways of sensitizing Lead Azide, mostly for comparison purposes between it and Silver azide.

SENSITIZATION OF HIGH DENSITY SILVER AZIDE
TO STAB INITIATION

Attachment: Silver Azide report.pdf (1MB)
This file has been downloaded 1006 times

Most of us probably don' t want these materials more sensitive, but understanding how it works is beneficial.


Here is something on Lead Azide sensitivity.
FRICTION SENSITIVITY OF PRIMARY EXPLOSIVES

Attachment: Lead Azide Sensitivity Testing.pdf (677kB)
This file has been downloaded 808 times

I have another pdf with lots of information on the different forms of Lead Azide among other things, but it is about 5.2MB.

[Edited on 11-8-2011 by Hennig Brand]

freebasing hydrazine related

Rosco Bodine - 13-8-2011 at 20:45

With regards to the freebasing of Hydrazine Hydrate from hydrazine sulfate, there are possibly some refinements upon the method that could be done to improve it, but I have not tried this. I will have to do more reading for this idea to be further contemplated. Anyway at the midpoint of the neutralization of hydrazine sulfate before actual freebase hydrazine hydrate is produced, the hydrazine is in the form of the so called neutral hydrazine sulfate or Dihydrazine Sulfate which is highly soluble. A half mole of sodium sulfate byproduct has also been produced ......or is it a mole of sodium acid sulfate, sodium bisulfate, that is the actual byproduct ? Anyway, I'm thinking half the byproduct H2O
exists already at the midpoint where the Dihydrazine Sulfate
exists because the hot mixture liquifies in the nascent byproduct water. And separately present in mixture is the
sodium ?sulfate byproduct. It may be possible and it could be helpful to separate the Dihydrazine Sulfate and isolate it
before further freebasing of it alone, since it is basically one third of the components present, thereby eliminating half the
byproduct water for the overall freebasing, and half the overall byproduct alkaline salt.....so a more compact and more concentrated "lode" of hydrazine salt source material
is then present for the final freebasing. Maybe the extra trouble would be worth the effort if it improved the process particularly for larger batches. What I am thinking is that there is known a low solubility double salt formation of calcium sulfate and sodium sulfate which is a method used
to remove the highly soluble sodium sulfate byproduct from solutions containing a product wished to be isolated free from sodium sulfate. This trick of using the calcium sulfate complexation double salt may work to produce a greatly cleaned up residual solution of Dihydrazine Sulfate, which
could be dried by evaporation to the anhydrous neutral salt.
Freebasing that neutral salt would likely be easier for the greatly reduced volume of solid byproducts. There are other reactions for which the neutral Dihydrazine Sulfate is actually very useful and required, or for half neutralization of the monohydrazine sulfate to be done in situ, so that is definitely a second reason for me to be thinking about a possible dual usefulness for the neutral salt making it possibly worthwhile to isolate the neutral salt in advance for whatever use. As a side note, if I recall correctly, a rough neutralization of the monohydrazine sulfate using aqueous ammonia will produce the neutral hydrazine sulfate and byproduct ammonium sulfate, but the aqueous ammonia is not a strong enough base to continue the neutralization further. So maybe one of the double ammonium salts could also have have a low enough solubility compared with the extreme solubility of the Dihydrazine Sulfate, that could also be exploited to facilitate isolation of the neutral hydrazine sulfate. Attached is an MSDS for Dihydrazine Sulfate


Attachment: dihydrazine sulfate MSDS.pdf (33kB)
This file has been downloaded 487 times


Hennig Brand - 23-8-2011 at 16:43

I was going to post a how-to, but for now I thought this basic overview might serve as a sort of chemical road map which should help one sort out a method. There is a lot of procedural information that was left out, which should be ironed out before attempting a synthesis. Keep in mind a lot of this stuff is very poisonous.

I referenced a book a couple of posts ago that has a couple of excellent chapters on the topic.


Hydrazine

Urea Method to produce Hydrazine
(H2N)2C=O + NaOCl + 2 NaOH → N2H4 + H2O + NaCl + Na2CO3

(I have seen it stated that a 62% yield can be obtained)


Acidify to neutralize the Na2CO3 and to precipitate the N2H4 as N2H4.H2SO4 (Hydrazine Sulfate) or maybe more properly writtten as N2H6SO4

Rosco's 2 step method seems like the best using HCl first, neutralizing the sodium carbonate and producing a very soluble sodium chloride by-product.

Na2CO3 + 2HCl → 2NaCl + H2O + CO2

Next Sulfuric Acid is used to precipitate the hydrazine sulfate.

N2H4 + H2SO4 → N2H4.H2SO4


Azides

1. Freebasing Hydrazine Sulfate to yield N2H4 (free hydrazine), KOH could also be used here. A slight excess of hydroxide is best.

N2H4.H2SO4 + 2NaOH → N2H4.2H2O + Na2SO4


2. Alcohol extractions of hydrazine are performed leaving behind insoluble Na2SO4.

3. The resultant alcoholic solution of hydrazine needs its volume increased by adding alcohol until it will dissolve an amount of sodium hydroxide (or potassium hydroxide) which will satisfy the equation below. Actually, a small excess of hydroxide should be used.

4. The isopropyl nitrite is added last. How it needs to be added depends on what alcohol is used as the reaction medium. The type of alcohol used will also dictate what the reactor requirements will be. Depending on the alcohol used, the reactor may need to be fairly sophisticated.

The main reaction producing azide:
N2H4 + CH3CH(NO2)CH3 + NaOH → NaN3 + CH3CH(OH)CH3 + 2H2O


Isopropyl Nitrite is needed for the above reaction. It is the ester of nitrous acid and isopropyl alcohol. Other alkyl nitrites can be used, but because of its lower vapor pressure isopropyl nitrite is relatively easy to make and use.

CH3CH(OH)CH3 + HNO2 → CH3CH(NO2)CH3 + H2O


Note:
Potassium Hydroxide could be used to do the freebasing as well as in the final reaction to produce KN3. I did one experiment where I used NaOH for the freebasing and KOH to produce KN3. The KN3 would have been contaminated with NaN3, but this was not a big concern for me.



[Edited on 24-8-2011 by Hennig Brand]

Glauberite byproduct possibly useful in freebasing

Rosco Bodine - 24-8-2011 at 06:25

In my preceding post I mentioned the possible use of a double salt of calcium sulfate and sodium sulfate to reach the half neutralization point in the freebasing of hydrazine sulfate. Attached is a patent US1343443 describing the usefulness of Glauberite CaNa2(SO4)2 which might be
a useful byproduct from the conversion of hydrazine sulfate to dihydrazine sulfate. The solubility optimum for this manipulation would need to be guessed and then the best amount of dilution with water determined by experiment. What is anticipated should work is to use for each mole of hydrazine sulfate, one quarter (1/4) mole of Ca(OH)2 and one half (1/2) mole of NaOH, the aqueous reaction mixture heated and stirred to produce a resulting concentrated aqueous solution of Dihydrazine Sulfate which may be decanted from the precipitated (1/4 mole) of crystalline Glauberite. This CaNa2(SO4)2 double salt is anhydrous, unlike usual sodium sulfate or calcium sulfate. The decanted concentrated solution of Dihydrazine Sulfate may then be evaporated with heating to leave a residue of Dihydrazine Sulfate which is also anhydrous. By means of this scheme half of the byproduct water of neutralization as would result from the freebasing of (mono) Hydrazine Sulfate is instead eliminated during the conversion of the monohydrazine salt to the dihydrazine salt. A more concentrated solid "lode" of hydrazine precursor material is present as the Dihydrazine Sulfate having twice the relative hydrazine content to become available when further reacted with a given amount of caustic alkali. In effect the Dihydrazine Sulfate is already halfway there with respect to neutralization requirement for freebasing, compared with the usual (mono) Hydrazine Sulfate.

The idea here involving the Glauberite is to improve the process chemistry of the freebasing to address a water solubility / water content issue which complicates things.
Refining the process with regards to freebasing may make the physical manipulations easier and could improve the yields. I haven't tried this, but it just seems like it should
work okay and would definitely make a good experiment
as a refinement on the process. Dihydrazine Sulfate is itself a useful reagent and required for some other syntheses, and there are descriptions of it being formed in situ from
the more common mono hydrazine sulfate by adding a half equivalent of base. If my hypothesis about the possible usefulness of forming Glauberite as the half neutralization byproduct is correct, then it should be possible to easily isolate the Dihydrazine Sulfate reasonably pure as a concentrated solution, which can be evaporated to provide the solid Dihydrazine Sulfate as a residue good for whatever further use, including completion of freebasing to release the hydrazine from a more compact mixture of solids which should be more easily separated from a more concentrated
lower water content hydrazine hydrate.

The deliberate targeting of byproduct Glauberite as the desired byproduct of even a complete freebasing may work better than the use of a single caustic alkali, since the Glauberite is more dense and is by nature an anhydrous material, it is probably less likely to pull hydrazine hydrate to itself along with water of hydration, as would occur for a byproduct sulfate derived from a caustic alkali which will go on to try to form hydrated salts, unless precipitated from hot solutions, and/or having that hydration tendency upset by alcohol.

It is unknown if the common ion effect of sulfate will cause an unexpected solubility for the Glauberite in the Dihydrazine Sulfate which could interfere with a clean separation and isolation of relatively pure Dihydrazine Sulfate. My hope of course is that the great solubility in H2O for the Dihydrazine Sulfate will substantially nullify the common ion effect for the
Glauberite which will be driven out of solution, crystallizing as its anhydrous double salt. There is nothing else I have found generally in the literature for guidance or illumination concerning whether such a scheme will work for Dihydrazine Sulfate. So there is only the attached patent US1343443 and
my educated guess this may work that I can share at this point.

Attachment: US1343443 Glauberite_CaSO4 - Na2SO4 double salt.pdf (103kB)
This file has been downloaded 557 times


Hennig Brand - 24-8-2011 at 12:23

That is interesting. It also emphasized something in my mind: using KOH to do the hydrazine sulfate freebasing adds a lot of water. I just did a quick and dirty calculation and it looks like you will end up with ~46% more water after freebasing when using KOH with 15% water, as opposed to using NaOH with 1% water. If you use the same KOH to make KN3 there is a little more water again, bringing you up to ~68% excess water total.

The method I am using uses quite a large amount of isopropanol, so a little extra water probably doesn' t make a big difference. For example when starting with 6.5g of hydrazine sulfate and using KOH the whole way (freebasing and right through to KN3), the water produced during freebasing and the water added with the KOH would bring the alcohol concentration in the reaction mixture down by ~2.5%. I am not sure how big a deal this is. It would effect the solubility of the azide product in the reaction mixture, but I am unsure of exactly how much. There would be much less dilution of the reaction mixture when using NaOH, one of the big reasons being that there is a lot more isopropanol to dilute, because of the much greater amount needed to dissolve the NaOH. I can see that with a smaller volume reaction mixture, like when using methanol, the extra water would be more problematic.


[Edited on 25-8-2011 by Hennig Brand]

Rosco Bodine - 24-8-2011 at 14:27

Yeah freebasing hydrazine into alcohol is definitely a tricky manipulation requiring good technique for it to go well, and there are probably some ways that freebasing can be refined and this seemed like one easy possibility. The use of an alcoholate for the post freebasing additional requirement of added alkali would also strip more water from the hydrazine hydrate extract. But these things are added steps and added work, which is exactly what was causing me to look at the nitrosation of semicarbazide to carbamoyl azide alternative, knowing the entire reaction there is done in aqueous solution and theoretically the carbamoyl azide will convert to ammonium azide in aqueous solution, by simple hydrolysis. This would be simpler in terms of the required manipulations if it works well.

Hennig Brand - 25-8-2011 at 13:16

As I understand it, the reason we are concerned with minimizing the amount of water in the reaction mixture is to reduce product loss in the post reaction mixture. The product loss comes from the greater solubility of the alkali azides in alcohol which has been diluted with water. I think you said before that sodium azide precipitates better and more completely from anydrous or near anhydrous alcohol. This is the main reason isn' t it? Are there other reasons?

So the Di-Hydrazine Sulfate has good chemical stability and resistance to oxidation similar to Mono-Hydrazine Sulfate (I assume), and there is only half the water produced when freebasing it relative to what is produced when freebasing Mono-Hydrazine Sulfate. Di-Hydrazine Sulfate sounds like it could be a more desirable hydrazine source, especially if one had a choice when purchasing, for instance. It seems like freebasing it might be a little more risky, with only just enough water to tie up the hydrazine as hydrazine hydrate. Yeah, if I had started out experimenting with Di-hydrazine sulfate I probably would have poisoned myself much worse than I did with the mono. I guess with a well sealed reaction vessel for freebasing (which is needed to exclude oxygen anyway) and some ventilation in the work area everything would be fine.

That is a neat trick to isolate the di-hydrazine sulfate, it seems like it would work quite well too.


[Edited on 25-8-2011 by Hennig Brand]

Rosco Bodine - 25-8-2011 at 21:16

Yeah the Dihydrazine Sulfate reportedly is stable. The reason the acidic salt, the monohydrazine sulfate is the common form is because it is the low solubility product precipitated from acidic solution which facilitates its isolation in relatively pure form from synthesis. So the monohydrazine sulfate is the common form of commerce, and the common form for the reagent. But definitely there are other forms of further processed hydrazine which are also stable and may be required for certain syntheses. It is a similar story for ammonia and other bases where various salts and/or even the anhydrous base are stable but have their various differing properties and reactivity and storage requirements, toxicity, volatility, ect. ranging from benign conditions to extreme. To make an analogy, hydrazine sulfate corresponds with ammonium bisulfate or sodium bisulfate and Dihydrazine Sulfate is the neutral salt corresponding with ammonium sulfate or sodium sulfate which more correctly and precisely in reality are Diammonium Sulfate and Disodium Sulfate.

As for the danger aspect of working with smaller volumes of material which should be easier to manipulate with the endproduct being the same hazard ....usually a simpler process manipulation of a smaller amount of raw material increases safety and is not any more risky ....so it seems it would about the same or lower risk. I can't really report an observation on this because I haven't actually done this yet to confirm. What works on paper doesn't necessarily always materialize that way in the experiment. But this one seems pretty straightforward like it ought to work okay.

There is another calcium salt of possible interest with regards to hydrazine conversion to azide and this is another possibility for experimentation which was mentioned in another thread.

http://www.sciencemadness.org/talk/viewthread.php?tid=874&am...

It has seemed possible to me that an organic nitrite may facilitate the reaction somehow and is more selective in converting hydrazine to hydrazoic acid than is free nitrous acid. It has therefore seemed possible that something like sorbitol or glycerin or isopropyl alcohol in an aqueous solution of a neutral hydrazine salt such as Dihydrazine Sulfate, might react as a regenerable intermediate organic nitrite with Basic Calcium Nitrite Ca(NO2)2 - Ca(OH)2 to yield an aqueous solution of Calcium Azide over precipitated Calcium Sulfate. The Calcium Azide solution might then be converted to a solution of Sodium Azide with precipitation of Calcium Carbonate, by treatment of the solution with Sodium Carbonate. This is another completely hypothetical and untested idea for an experiment.
It may not work at all in a beaker even though it seems to work fine on paper.

Attached is US4294813 which describes a synthesis of Basic Calcium Nitrite from Sodium Nitrite and Calcium Nitrate

Attachment: US4294813 Calcium Nitrite from Sodium Nitrite.pdf (103kB)
This file has been downloaded 770 times

[Edited on 26-8-2011 by Rosco Bodine]

Formatik - 5-9-2011 at 23:33

Quote: Originally posted by Rosco Bodine  
The experimental part of the attached describes the reaction of nitrous acid and semicarbazide producing a 70% yield of Carbamyl Azide.

A translation of the relevant portion would be helpful if anyone may assist, thank you.



Über die Ultraviolett-Absorption und Konstitution von Tetrazenen aus Aminoguanidinsalzen
Ruth Hofsommer, Max Pestemer

Zeitschrift für Elektrochemie und angewandte physikalische Chemie
Volume 53, Issue 6, pages 383–387, Dezember 1949

DOI: 10.1002/bbpc.19490530612


The method given there they state is originally from the referenced Thiele and Stange. But they mixed an aq. solution having 22.2g semicarbazide-hydrochloride with a solution of 14g NaNO2 in 25 ccm H2O, under a lot of stirring then saturating with ammonium sulfate, then repeated extraction with ether, to obtain the azide in 70% yield. They also recrystallized it from hot ether. The azide is hydrolytically unstable and according to the article hydrolyzes to CO2, NH3 and HN3.

The other article from Curtius and Schmidt states carbamoyl azide is pretty easily soluble in cold water. Boiling decomposes the solution: NH2CO.N3 + H2O = NH4N3 + CO2. Some urea forms as a side product. Although carbamoyl azide can also be melted with slow heating without explosion, in circumstances (e.g. copper powder can catalyze decomposition) it can explode with the force typical of the azides.

The other compound briefly mentioned in Beilstein in the hydroxylamine nitrate thread with two azide groups, N3.C=O.N3, is extremely dangerous, and volatile from what I've read. It's the azide analogue of phosgene. It is like but maybe worse than nitrogen triiodide, and closer to RDX in power. Carbamoyl azide preparation is one molecule less nitrite removed from forming carbonyl diazide.

Quote: Originally posted by Rosco Bodine  
Also back on page 3 and 4 of his thread S.C. Wack posted some attachments which are are scans of articles relating to oxidation of hydrazine sulfate with H2O2 and nitrous acid and other oxidizers. Some more legible scans are now available and these are also attached as an update.

A New Synthesis of Hydronitric Acid (attached)
The Oxidation of Hydrazine (attached)


I would say this method is a waste of sulfuric acid, not more than a novelty interest. The residual H2SO4 would have to be purified by distillation. And you would need a lot of H2SO4 for just a small amount. I have also tried it some time ago using their suggested 3% H2O2 as the oxidant, I was only able to obtain several gas bubbles of hydrogen azide even after heating the apparatus for some time over the hot plate.

On that note, I've overestimated the hazard of hydrogen azide. It is the anhydrous pure (and maybe near pure) substance and not its solutions and water vapor containing vapor which make hydrogen azide bizzarely dangerous to work with. Curtius, the inventor of the stuff has said something along the same lines. Hydrogen azide is a nasty toxin though, a waft of air from the amount in the reaction flask that was heated before, immediately caused me to stop breathing out of my nostrils.

Rosco Bodine - 6-9-2011 at 08:10

Thanks for the insight gotten from the german text. Isolation of the carbamoyl azide was something which I never anticipated doing, but contemplated simply heating the completed semicarbazide nitrosation reaction mixture to accomplish the hydrolysis of the crude carbamoyl azide to ammonium azide, followed perhaps by reaction with calcium hydroxide to drive off ammonia and leave a solution of calcium azide, then treated with sodium carbonate to precipitate calcium carbonate and leave a solution of sodium azide, evaporated to obtain the solid, or keeping the sodium azide solution for use as such. From the description it appears the carbamoyl azide is marginally stable the same as guanyl azide, and its reactions have been described as being analogous also. It has been my expectation and curiosity if the carbamoyl azide crude reaction mixture resulting from the nitrosation of semicarbazide would further react with cyanamide or dicyandiamide to form 5-aminotetrazole, via hydrolysis of the carbamoyl azide to ammonium azide which should then react further in the same way as would sodium azide. If not then perhaps a conversion to the sodium azide solution as described would enable the process starting from semicarbazide, leading to first sodium azide, and later if desired to 5-aminotetrazole, having semicarbazide as a versatile starting material for sodium azide, convertible by further reaction to 5-aminotetrazole as a one pot perocess for either. An additional curiosity has been if the crude carbamoyl azide would form a picrate as does guanyl azide picrate, and if carbamoyl azide can also form salts such as a nitrate and a perchlorate similarly as guanyl azide forms salts. Anyway it is an interesting possibility to be able to use semicarbazide as a starting material, leading to azides and tetrazoles, if it could work as I have been thinking it may work.

Formatik - 6-9-2011 at 12:23

Triazoles and urazoles (triazolidindiones) has been done from semicarbazide. These are already interesting starting points. Nitrotriazolone (NTO) is about as strong as RDX. Apparently nothing has been done with urazoles as far as energetics are concerned.

There are no indications of carbamoyl azide forming any salts, the only thing mentioned in Beilstein is hydrolysis by heating with aq. NaOH, or dilute acids, which is similar to water hydrolysis.

Rosco Bodine - 6-9-2011 at 12:42

Yeah it was unclear if during the hydrolysis ammonia was liberated separately and was volatile or if it actually neutralized the hydrazoic acid simultaneously forming ammonium azide....it has been described both ways so it was some uncertainty if a separate base like calcium hydroxide or sodium hydroxide may be necessary to be present during the hydrolysis to guarantee sequestration of the liberated hydrazoic acid as a non volatile azide salt in solution. Not enough of the German could I follow well enough to find the subtle details like that. However it does seem possible to go further from hydrolysis of the carabamoyl azide to the 5-aminotetrazole and this tie in with the discussion in the tetrazole thread too, where nitrosation of guanidine leads to unidentified but interesting products.
Obviously there are some potentially useful methods possible to be found in these related reactions which might be sequenced in a way not yet reported, as a simplified route to both azides and tetrazoles. So this seems very interesting, also interesting that such a scheme hasn't been reported yet, at least to my knowledge, it may just be obscure or in a different language journal waiting to be found. So I may be reinventing the wheel a bit for that reason.

Rosco Bodine - 24-2-2012 at 21:27

Should probably put this here too....Solubilities for Hydrazine Sulfate and Dihydrazine Sulfate
Can't find a chart for the solubility curve, so I borrowed this excerpt via printscreen screenshot, you know sort of ripped it ......sharing is caring


Bhaskar - 3-3-2012 at 10:10

Quote: Originally posted by Polverone  
Quote:
Originally posted by froot
I found an interesting route to NaN3 and HN3 from a old book called 'Van Nostrand's scientific encyclopoedia'
Word for word as follows;

Hydrazoic acid is formed (1) by reaction of ethyl or amyl nitrite in NaOH solution (sodium azide formed), then acidifying with dilute H2SO4 and distilling. Hydrazoic acid is recovered mainly in the early portion of the condensate

I am sure that the first reaction is wrong. There needs to be hydrazine in there. Alkyl nitrite + NaOH just results in an alcohol and sodium nitrite.
Are u completely sure on the ethyl nitrite and sodium hydroxide forming hydrazoic acid reaction? Because i realy wanted to synthesis my first azide...

AndersHoveland - 3-3-2012 at 15:45

Quote: Originally posted by Bhaskar  
Are u completely sure on the ethyl nitrite and sodium hydroxide forming hydrazoic acid reaction? Because i realy wanted to synthesis my first azide


The encyclopedia entry obviously made a mistake. They seem to have confused the common procedure, which is to first react the alcohol, NaNO2, and the acid to make the nitrite ester, then react with hydrazine hydrate and NaOH to get the sodium azide.

Reacting aqueous sodium hydroxide with ethyl nitrite will only form sodium nitrite and ethanol.

Bhaskar - 4-3-2012 at 01:32

thank you

Bhaskar - 4-3-2012 at 04:33

Can somebody to direct me to FTP2 under upload/rogue chemist/Lead azide please?

Bhaskar - 5-3-2012 at 23:31

where can i find FTP2 under upload/rogue chemist/Lead azide??

Ral123 - 15-6-2012 at 12:08

Here's a video of the tests I was able to make with the very rare primary-lead azide.
http://www.youtube.com/watch?v=V3wejJ23LLs&feature=youtu...
It has very short ddt and is also has unbelievably good storage stability compared to conventional primaries. The very high density I guess also adds self-confinement effect.

Rosco Bodine - 28-3-2013 at 21:19

This may be of interest WRT the possible route to sodium azide via nitrosation of semicarbazide. A caveat should be understood that this information is untested by me, but his is what I am understanding from the literature, which provides the information in a piecemeal fashion. What would be the overall efficiency or safety of such a route to sodium azide as I am describing I do not know, but it appears to be reasonable.

http://www.sciencemadness.org/talk/viewthread.php?tid=3248&a...

Likewise nitrosation of hydrazodicarbonamide leads to carbamoyl azide,

http://www.sciencemadness.org/talk/viewthread.php?tid=6729&a...

but it appears that semicarbazide as the precursor may be the easier intermediate.

Edit: Actually the hydrazodicarbonamide ( Biurea ) is not difficult. It may be made from hydrazine sulfate and urea, or by other methods.

US2692281 Biurea from hydrazine sulfate and urea
US3227753 Biurea or Hydrazine from Hypochlorite and Urea


The patent GB790066 describes a very interesting method of producing what is probably semicarbazide sulfate from a reaction of equimolar amounts of hydrazine sulfate and nitrourea in an aqueous system with nitrous oxide being evolved as a byproduct. The patent description is not very comprehensive so here I am doing some "reading between the lines" hopefully with understanding that is correct.

Semicarbazide sulfate would seem to be desirable as a prescursor for carbamoyl azide via nitrosation with sodium nitrite. The sulfate could be removed from the reaction mixture by use of hydrated lime or perhaps calcium nitrate.
The glauberite precipitation scheme for sulfate removal may be useful here, but I have not checked this to be sure.

http://www.sciencemadness.org/talk/viewthread.php?tid=1987&a...

The filtered carbamoyl azide solution should upon heating decompose to a solution of ammonium azide, which may be obtained upon evaporation as a stable non hygroscopic crystalline solid. Or the ammonium azide may be converted to sodium azide by addition of NaOH or perhaps in the alternative sodium carbonate or bicarbonate, and boiling to expel byproduct ammonia, eavaporating to dryness to obtain the sodium azide.

Attachment: GB790066 Semicarbazide from Nitrourea and Hydrazine Sulfate.pdf (361kB)
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Attachment: US2692281 Hydrazodicarbonamide from Hydrazine sulfate and Urea.pdf (76kB)
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Attachment: US3227753 Biurea (Hydrazodicarbonamide).pdf (254kB)
This file has been downloaded 386 times

Some help is needed for translation of the German to English for the nitrosation of biurea (hydrazodicarbonamide) to carbamoyl azide, as described in the article attached above Ueber Semicarbazid. Page 40 is what appears to be of interest.

http://www.sciencemadness.org/talk/viewthread.php?tid=1987&a...



[Edited on 29-3-2013 by Rosco Bodine]

review of untested possible aqueous reaction system methods

Rosco Bodine - 30-3-2013 at 08:07

Quote: Originally posted by Rosco Bodine  
Yeah the Dihydrazine Sulfate reportedly is stable. The reason the acidic salt, the monohydrazine sulfate is the common form is because it is the low solubility product precipitated from acidic solution which facilitates its isolation in relatively pure form from synthesis. So the monohydrazine sulfate is the common form of commerce, and the common form for the reagent. But definitely there are other forms of further processed hydrazine which are also stable and may be required for certain syntheses. It is a similar story for ammonia and other bases where various salts and/or even the anhydrous base are stable but have their various differing properties and reactivity and storage requirements, toxicity, volatility, ect. ranging from benign conditions to extreme. To make an analogy, hydrazine sulfate corresponds with ammonium bisulfate or sodium bisulfate and Dihydrazine Sulfate is the neutral salt corresponding with ammonium sulfate or sodium sulfate which more correctly and precisely in reality are Diammonium Sulfate and Disodium Sulfate.

As for the danger aspect of working with smaller volumes of material which should be easier to manipulate with the endproduct being the same hazard ....usually a simpler process manipulation of a smaller amount of raw material increases safety and is not any more risky ....so it seems it would about the same or lower risk. I can't really report an observation on this because I haven't actually done this yet to confirm. What works on paper doesn't necessarily always materialize that way in the experiment. But this one seems pretty straightforward like it ought to work okay.

There is another calcium salt of possible interest with regards to hydrazine conversion to azide and this is another possibility for experimentation which was mentioned in another thread.

http://www.sciencemadness.org/talk/viewthread.php?tid=874&am...

It has seemed possible to me that an organic nitrite may facilitate the reaction somehow and is more selective in converting hydrazine to hydrazoic acid than is free nitrous acid. It has therefore seemed possible that something like sorbitol or glycerin or isopropyl alcohol in an aqueous solution of a neutral hydrazine salt such as Dihydrazine Sulfate, might react as a regenerable intermediate organic nitrite with Basic Calcium Nitrite Ca(NO2)2 - Ca(OH)2 to yield an aqueous solution of Calcium Azide over precipitated Calcium Sulfate. The Calcium Azide solution might then be converted to a solution of Sodium Azide with precipitation of Calcium Carbonate, by treatment of the solution with Sodium Carbonate. This is another completely hypothetical and untested idea for an experiment.
It may not work at all in a beaker even though it seems to work fine on paper.

Attached is US4294813 which describes a synthesis of Basic Calcium Nitrite from Sodium Nitrite and Calcium Nitrate


Identifying possible routes to azides which are workable in an aqueous system has been something that I have had in mind for 10 years because it would simplify the syntheses for not requiring use of alcohol as a solvent and would eliminate that expense as well as eliminate the tedious extra efforts attendant to manipulation methods and strategies seeking low water content in the reaction system.

There was brief discussion between myself and Engager in another thread linked in the quote above referencing the silver azide gotten by Hogkinson as an indirect method reported for producing azide in an aqueous system. That method is one which I have tried and been unable to reproduce, which lets me know it is a fickle reaction having a narrow window for conditions which will work, that I was unable to reproduce. The literature in general does not offer much helpful and detailed information about synthesis methods for azides from an aqueous reaction system, but makes only brief references to the azides being produced as products of decomposition of the subject material of such literature where the precursor for the azide is given the authors attention, and the isolation of azide as the intended reaction product is not contemplated. So the available literature is very brief and not very helpful in regards to describing any syntheses done in an aqueous reaction system where azide is the intended product. That absence of information is the cause of interest in formulating experiments which seek to provide good information which fills that obvious deficiency in the literature. Even textbooks, at least the older texts make oversimplified references to how azide is obtainable, generally referencing Curtius use of KNO2 and Hydrazine Sulfate, and providing no details. So bravo to Curtius step right up and tell us all about it how it is done. :D Until then we shall examine what may be "other" bona fide methods than proposed by either Curtius or Hogkinson, frankly both of which reports I greet with skepticism born of experience having difficulty confirming their reports. I have successfully made azide many times and different ways, but all of these variations still have involved free hydrazine in alcohol reacted with an organic nitrite in the presence of a base. It is perplexing to identify the alternate conditions where an aqueous reaction system may be used with good results.

Three possible methods using an aqueous reaction system have been identified. The method proposing use of Calcium Nitrite and Hydrazine Sulfate perhaps in the presence of a polyol described above and in the linked discussion with Engager is one method I have contemplated but have not tested. The other two methods are the hydrolysis of a carbamoyl azide intermediate briefly described by literature as obtainable from nitrosation of semicarbazide or hydrazodicarbonamide ( Biurea )

From what little time I have been able to spend on this interest at times over the course of the past 10 years of following these threads and looking at the literature this is my summary review of my own conclusions and my impression of where experiments have led and the 3 most promising methods yet to be examined.

The methods involving alcohol reaction systems are solidly proven to work as methods for synthesis. But the possible methods involving an aqueous reaction system remain inadequately reported and/or mostly unexplored, untested, and speculative .....for now.

[Edited on 30-3-2013 by Rosco Bodine]

Hennig Brand - 31-3-2013 at 05:50

This is very interesting. I will keep my eyes open and see if I can find anything pertaining to the subject. I didn't really look much farther than the alcohol methods when I first learned to make azides. I was very happy and contented when I learned how to make it work. Though a large amount of costly alcohol is used those methods are very reliable and robust, solidly proven as you have described.

I will keep my eyes open for alternative methods. The azides really are so many times better than the other primaries I was experimenting with prior to.

Rosco Bodine - 31-3-2013 at 11:42

Yes azides are definitely a subject of interest for which a good practical working knowledge is a priority for anyone interested in the scientific art associated with initiating explosives. It could be prioritized as "Explosives 101" kind of fundamental must have knowledge buried and hidden among that voluminous work they would not dare to teach in college :D , a deficiency and oversight which any aspiring "blaster" would then seek to remedy as knowledge gotten from "independent further research". Of course that would be the point to not "spoon feed" every secret thing to the student, but only sufficient knowledge to operate as a provocation to the student who must then solve any remaining mystery for themself. We are taught only to a point, and thereafter we are self-taught and this is probably by design. The impatient to know would criticize the design and question its necessity, question the teachers, question the intelligence of the design. It is what it is.

If we stick with the well proven non-aqueous methods there would still seem to be improvements possible to be made in the manipulations. My personal impression is that a scheme which uses the dihydrazine sulfate prepared in advance as the material which will be freebased into alcohol, very likely would represent such an improvement. Isopropyl alcohol is a good choice for the alcohol as described for the method of microtek and its variations. There possibly could be advantage for use of different organic nitrites other than isopropyl nitrite, or maybe not. Surveying the possibilities there are other organic nitrites which may have lower vapor pressure and possibly adequate stability, and which will either react directly with the hydrazine in isopropanol or will transesterfy in situ to the isopropyl nitrite which will allow the desired reacton to proceed. Depending upon availability other alternative solvent alcohols are also workable. So it appears that the "alcohol solvent method" is general and may be subject to variations at the technicians discretion which may serve as refinement applied to the same basic method.

Ultimately there will be found several slightly different but still related methods all of which are workable with each approach having its advantages or disadvantages compared with another variation. What will ultimately prove to be the "best" all around combination of solvent alcohol, organic nitrite ester, and base, and hydrazine salt precursor material, is left to be sorted out with further experiments, while encouraged to know that decent yields are probable to be gotten from any of the variations, as whatever variations are tested to try to optimize the particular combination.

There is plenty there to digest when surveying the "process chemistry" involved, plenty of food for thought there for the hungry mind of the curious experimenter.

[Edited on 1-4-2013 by Rosco Bodine]

Hennig Brand - 31-3-2013 at 14:15

This is what I had of Microtek’s; there may be other posts that I am unaware of. Keep in mind these posts are almost 10 years old.

From E&W
"Microtek
September 9th, 2004, 12:00 PM
For sodium azide production I use a method which gives hydrazine in alcohol (from hydrazine sulfate) with little or no water:

- 1 mol dry HS is placed in a flask along with a suitable amount of anhydrous isopropanol.
- 1 mol of NaOH pellets are added and the contents are triturated with a glass rod until they begin to react, forming a slurry of hydrazine hydrate and NaHSO4. This doesn't mix with the iPrOH, but forms a sticky goo on the glass.
- Another 1 mol NaOH is added which converts the NaHSO4 to Na2SO4 ( and forms a mol of water ) which separates cleanly as a white powder.
I would think that the Na2SO4 is a good enough dessicant to dry out the solution which can then be decanted.
- Another extraction or two with dry iPrOH recovers most of the hydrazine.

This alcoholic solution of hydrazine works well for producing sodium azide with isopropyl nitrite."

I also have this from E&W (2005), part 2 of his azo-clathrate synthesis.

"2) Production of hydrazine hydrate: 13 g hydrazine sulfate is placed in a suitable vessel along with 15 mL IPA, 99%. 4 g solid NaOH is added and the pellets are crushed and triturated with the HS. After a few minutes, the powdered reactants will attain the appearance of a paste as the produced NaHSO4 stubbornly holds on to the produced hydrazine hydrate. The paste is worked through a little more to ensure complete reaction, and then another 4-5 g solid NaOH is added and worked into the paste to convert the NaHSO4 into Na2SO4 which separates cleanly as a crisply dry powder.
The IPA solution of hydrazine hydrate is removed by decatation or with a syringe, and
the remaining powder is extracted a further two times with 10 mL IPA.

The advantage of using only IPA is that there is no possibility of cross-esterification during the reaction of isopropyl nitrite with hydrazine hydrate, so there is no need to carry out the operation under pressure. Also, the practically anhydrous conditions causes the sodium azide to precipitate completely and instantaneously from the reaction mixture as the nitrite is added."

A lot of what he said was very helpful, but what I also found was that I had to use a lot more isopropyl alcohol in order to dissolve the amount of sodium hydroxide necessary to balance the reaction equation. I also found that the product was not produced immediately, but took half an hour or more at room temperature before much of any product was seen and then 2 or more days to approach completion. He may have done many things differently to control the reaction conditions, but I have not seen those posts. When operating at room temperature, I found using KOH to be a big improvement.

I think this part is mine, though I am sure somebody somewhere has done it before.
It may seem like a simple modification (and it is), but using potassium hydroxide in place of sodium hydroxide when using isopropyl alcohol as the solvent provides a huge economy in alcohol (since KOH is much more soluble than NaOH in isopropyl alcohol) and time (since the reactants are at a much higher initial concentration).

You can lead a horse to water, but you can't make him drink (I'll give you that). Not all knowledgeable people are generous with their knowledge either though. Like you say these things are probably natural, even with large amounts of spoon feeding generally people need to work with the material in order to really grasp what is going on.


[Edited on 31-3-2013 by Hennig Brand]

franklyn - 31-3-2013 at 16:38

A passing thought I had

Ammonium Nitrate is decomposed by Hydrazine , replacing and liberating
Ammonia to form Hydrazinium Nitrate

NH4NO3 + N2H4 => NH3 + N2H4•HNO3

so what about Ammonium Nitrite to form Hydrazinium Azide.
Nitrite will oxidize Hydrazine just the same as it does Urea.

NH4NO2 + 2 N2H4 => NH3 + N2H4 + N2H4HNO2 => NH4OH + H2O + N2H4HN3


on Ammonium Nitrite
www.sciencemadness.org/talk/viewthread.php?tid=23807
www.sciencemadness.org/talk/viewthread.php?tid=6650

______________________________________________


Upon further reflection ( and meta search ) it appears things are
not as straight forward as one can hope for. According to The
Encyclopedia of Explosives & Related Items - PATR 2700
Hydrazinium Nitrite is a known stable salt , making it's further
transition to azide dubious.

H 196
Hydrazine (or Hydrazinium) Nitrite. N2H4•HNO2 ;
mw 79.06, N 53.15%; decomp or explodes on rapid heating;
colorless to yellowish hygr solid; sol in w & alc; insol in eth;
may be prepd by mixing solns of barium nitrite and neutral
hydrazine sulfate, as described in Mellor (Ref 1).
Explodes violently on impact and less so when rapidly heated.
When heated slowly it decomposes according to the equation:
N2H4•HNO2 => NH3 + N20 + H20
and this decompn is greatly accelerated by nitrous acid.
Refs:
1) Mellor 8, 472-3 (1946)
2) F.Sommer, ZAnorgChem 83, 119 (1913)
3) Clark, Hydrazine (1953), p 6

the often cited reaction of hydrazine with nitrite to form azide is
also clearly stated


H 192
Hydrazine is used for the preparation of hydrazoic acid according to:
N2H4 + HNO2 => HN3 + 2H20
or for the preparation of sodium azide (Ref 14).
14) Ulmann, 6, 206, Encyklopädie der Technischen Chemie (1951)

the essence of what I propose above is clearly mentioned also

A 606
pure NaN3, made from N2H4 and NH4NO2
(Ref 54) J.Nelles, Ber 65B, 1345-7 (1932) & CA

as is the reaction analogous to hydrazine with ammonium nitrate

A 537 - Hydrazinium Azide
prepd by pouring hydrazine hydrate over ammonium azide
and evapg the mixt in a flat dish placed in a desiccator. This
latter method of prepn was patented by Miller in 1936 (Ref 10).
10) E.Müller, GerP 634688 (1936) & CA 31, 511 (1937)


so what is one to think, experimentation will tell.

____________________________________


If someone is wondering about that apparent nonsequitor referring to
Ethylene Glycol Dinitrite posted by Rosco Bodine below, see _
www.sciencemadness.org/talk/viewthread.php?tid=6395&goto...

.

[Edited on 1-4-2013 by franklyn]

Rosco Bodine - 1-4-2013 at 01:23

Quote: Originally posted by Rosco Bodine  
If we stick with the well proven non-aqueous methods there would still seem to be improvements possible to be made in the manipulations. My personal impression is that a scheme which uses the dihydrazine sulfate prepared in advance as the material which will be freebased into alcohol, very likely would represent such an improvement.


Hmmm, why didn't I think of that? I've caught myself reinventing the wheel while reviewing the matter. The original patents regarding freebasing hydrazine into alcohol were in fact done using dihydrazine sulfate, which would simplify things as I have been thinking. So the freebasing done from the monohydrazine sulfate has been taking a short cut, which causes twice the byproduct water from neutralization and increases the amount of alcohol being needed for the extraction.

http://www.sciencemadness.org/talk/viewthread.php?tid=1128&a...

These are some pertinent references

GB900397 Freebasing hydrazine in ethanol

GB876038 Frebasing hydrazine in methanol

US3015542 US issue of GB900397

US2166698 ethylene glycol dinitrite

Attachment: GB900397 hydrazine extract using ethanol.pdf (284kB)
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Attachment: GB876038 Hydrazine extract in alcohol.pdf (249kB)
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Attachment: US3015542 Hydrazine in Ethanol from dhydrazine sulfate.pdf (113kB)
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Attachment: US2166698 ethylene glycol dinitrite and glycerin nitrite esters.pdf (175kB)
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[Edited on 1-4-2013 by Rosco Bodine]

Hennig Brand - 1-4-2013 at 07:35

I remember you bringing up dihydrazine sulfate a year and a half ago or more. It is a good idea which reduces the amount of water produced by half. I am not quite sure why more water would require that there to be more alcohol used for extraction. I thought the water was a problem because it caused more of the sodium or potassium azide product to be dissolved or lost in the reaction mixture.

There seemed to be an indication from some of the earlier posts that the sodium sulfate produced during freebasing may be absorbing much of the water produced, but I don't know. The idea of using desiccants might be a good one.

Description of Drierite taken from http://www.chem.ucla.edu/~bacher/Specialtopics/Drying%20Agen...

Calcium sulfate (n=0.5, e=0.004 mg/L) is a neutral and good drying agent. However, it does not have a high capacity, which makes it useless for very wet solutions. The commercially available Drierite contains cobalt chloride as indicator (dry: blue, wet: pink), which can be leached out into various solvents i.e. ethanol, DMSO, DMF, ethers, etc. Drierite is often used in desiccators. If the compound is pink, the water can be removed by heating the compound to 210 oC for an hour.

The text "Purification of Laboratory Chemicals" says isopropyl alcohol can be dried by adding CaSO4.

Could calcium sulfate or some other desiccant be added before or during the extraction process to remove water?

I know Rosco mentioned Glauberite [Na2Ca(SO4)2] in some previous posts.



[Edited on 1-4-2013 by Hennig Brand]

Rosco Bodine - 1-4-2013 at 09:50

I was having a little fun earlier with some folks here, probably with Len in mind more than others, sorry I couldn't resist :D

Look again at the titling on that post paragraph linked above usual behavior of hydrated salt does not apply and you will understand why it would be of limited usefulness to try to use any ordinary dessicants to try to dry an alcohol solution of hydrazine hydrate. The hydrazine hydrate tenaciously holds onto water and wins the tug of war for the water unless some special approach is used like distillation fractionation or azeotroping a solvent / water mixture, or in the alternative to use chemically reactive schemes like an alcoholate such as sodium ethoxide or sodium methoxide as a part of the neutralization scheme in place of simply using a base like NaOH simply dissolved in the alcohol.

The speculation which I was making about Glauberite was more intended towards a cleaner precipitation of the sulfate byproduct of the freebasing having a more compact crystalline form, than was it meant to address at all the byproduct water, which Glauberite would not do anyway since Galuberite is an anhydrous double salt. The Glauberite would likely have its greatest utility in the prelimary conversion of the monohydrazine sulfate to dihydrazine sulfate where the dihydrazine has such great solubility in water, and before an alcohol system is later used for the freebasing scheme applied to a previously isolated and dried dihydrazine sulfate. It is possible the Glauberite may have utility also in the freebasing scheme, but it would not be any dehydrating property that is the reason. The lowered solids content would make for easier physical manipulation to stir a slurry of sulfate byproduct, and by working with dihydrazine sulfate there will only be half the bulk of byproduct sulfate, as well as half the byproduct water in the freebasing and extraction stage.

The added quantity of alcohol for the more shortcut scheme is simply the relative amount of alcohol being greater to have an end resulting solution having a comparable concentration of water. Twice as much alcohol is required for the shortcut scheme (at least) and maybe even a little more in comparison to the proposed scheme which involves an easier manipulation for physical reasons.

If an alcoholate is contemplated being used also as a chemically reactive dehydration, there is benefit there also because only half as much byproduct water is encountered when freebasing the dihydrazine sulfate as is gotten by the "one pot" shortcut method. For a bulk synthesis expecially where a larger amount of material will be made, these refinements would be of greater concern with regards to the efficiency of the process. For small scale syntheses, the simplicity of the "short cut" method makes waste of solvent or inefficiency less concern, but for any scaling up of the process, the usefulness of the refinements would become apparent. Since I tend to work medium scale then I am more aware of these kinds of "process" efficiencies, which could also be applied to the smaller scale if it was estimated to be worth the extra effort on the smaller scale.


Hennig Brand - 1-4-2013 at 10:51

Ok, now that I am looking at the reaction equations I see that all the water produced is bound to the hydrazine forming hydrazine hydrate. For some reason I was thinking of unbound water (it has been over a year since I really looked at this at all, and I'm not really a chemist).

When using isopropanol the amount of alcohol used is dictated by its rather low ability to dissolve the hydroxide. The saving grace seems to be that the azide products also seem to be very insoluble in isopropanol.

Yeah, efficiency really isn't a great big concern for me because I am usually only making a few grams for some caps. When you are only using 0.3g per cap, a few grams can go quite a long way. If it costs me an extra buck or something to make a small batch it is no big deal, especially if it saves me time and effort. I can see how my methods would be very uneconomical large scale though.

Rosco Bodine - 1-4-2013 at 11:07

To expound upon what I am trying to communicate it would be good to see the following post in the dedicated hydrazine thread. It further describes what is contemplated as a method for virtually anhydrous hydrazine in isopropanol possible to be gotten by freebasing dihydrazine sulfate using aluminum isopropoxide in isopropanol. I do not know if this has ever been done. But it appears to be the logical progression that such a proposed route is possible.
http://www.sciencemadness.org/talk/viewthread.php?tid=1128&a...

As an aside there is also some modification of the hydrazine synthesis reportedly using manganous sulfate as a catalyst. The "Russian method"
from a Russian textbook Practical_Inorganic_Chemistry.Vorobyova.O.I_Dunaeva.K.M_Ippolitova.E.A_Tamm.N.S.1987
http://www.sciencemadness.org/talk/viewthread.php?tid=1128&a...

There is a patent reported US3227753 Biurea or Hydrazine from Hypochlorite and Urea which describes a similar process so this may be of interest as a possible further refinement on the hypochlorite urea process.

http://www.sciencemadness.org/talk/viewthread.php?tid=1128&a...

Scale absolutely has bearing on the choice of methods used for convenience. Shortcuts are allowed for small scale work, and I never really explained before that was what was deliberately done to make a "one pot" method from a generally more complicated industrial process. It is good to know this however, because it can apply if any scaleup is contemplated or if problems are encountered with the small scale "one pot" methods, then those problems may be resolved by the longer route or other measures done to refine the process.

Brainstorming is allowed also. For example I just thought of the possible refinement of using aluminum isopropoxide in ethanol, denatured alcohol to do the freebasing of dihydrazine sulfate, resulting in anhydrous hydrazine in ethanol with a small percentage of byproduct isopropanol, a solvent system being mostly ethanol in which the NaOH would be highly soluble. Then for the nitrosation a low volatility nitrite like diethylene glycol dinitrite, or alternately butyl nitrite or amyl nitrite, or if stability of glyceryl di or trinitrite is sufficient, then the glyceryl nitrite could be used.
Such a scheme could lead to a quantitative yield for the process regardless of scale.

So now you know where "Mr. Anonymous" was going with all of this that took ten years to get said ....connecting all the dots. Dots are hereby declared "connected". :D

I really wanted to get all these details down before the next forum backup so the communication transmission would be complete. I'm sure there was an article or two missed along the way, but that is pretty much all I've got on this to this point, for the "hydrazine chronicles" or Martian (lander) chronicles, or azide / tetrazole chronicles ....whatever. :D It has been a long ride, but a lot of fun sharing.

[Edited on 1-4-2013 by Rosco Bodine]

Hennig Brand - 2-4-2013 at 12:31

Thanks for sharing. Contributors like you, Microtek and some others have definitely helped me develop some of the skills I now possess.

As Microtek originally said isopropanol is good in the sense that there is no possibility of cross esterification. What I need to figure out is a way to add the reactants (or at least the sodium/potassium hydroxide) to the reaction mixture, in the isopropanol solvent, in small increments instead of all at once. If I could do that the process would require a lot less alcohol. I suppose at the scale that I am working at this sort of process, with increased complexity, is probably not going to be much of an advantage all costs including time considered.

[Edited on 2-4-2013 by Hennig Brand]

Rosco Bodine - 2-4-2013 at 13:19

If anybody had told me that an anonymous post here would lead to a ten year incremental tour of the literature with review of experiments and proposed experiments involving hydrazine and related compounds, I would have chuckled and said sure, 10 years huh, you gotta be kidding me. But truth is stranger than fiction. This has got to be an internet discussion forum record of some kind. This azide thread should get a sticky IMO. It seems to be the main thread for azides, and along with tetrazoles seems to be a natural related interest energetic material for the general topic of hydrazine.

The process refinement priority for the alcohol reaction system which seems most promising would be preparing and isolating the dry dihdrazine sulfate in advance as the precursor for freebasing.

Hennig Brand - 2-4-2013 at 13:47

I have been wondering for a long time why this thread was not stickied.

Since brainstorming is allowed, I have another idea.

Notes on the Preparation of Absolute Isopropanol

Lewis Gilson

J. Am. Chem. Soc., 1932, 54 (4), pp 1445–1445

Publication Date: April 1932

Attached jpeg of the note on concentrating isopropanol.

Note on the Preparation of Absolute Isopropanol.jpg - 69kB

I don't know but it looks like maybe the isopropanol could be used over and over again. Just remove water and use it again. Again probably not worth the bother, but it might be worth saving the solvent and doing it in large batches.

I suppose since the isopropanol is used in such large proportion compared to what is used in the case of ethanol or methanol, the solvent could probably just be recharged with reactants and used again.

[Edited on 2-4-2013 by Hennig Brand]

Rosco Bodine - 3-4-2013 at 00:50

In an earlier post I was speculating that aluminum isopropoxide could be useful for freebasing hydrazine from dihydrazine sulfate, but thinking more about this it seems like the use of that reagent could be problematic a couple of different ways. I don't know if this first possible complication would occur but it does seem possible.

http://www.sciencemadness.org/talk/viewthread.php?tid=1128&a...

The possibility of a complication presented by the insolubility in the isopropanol of any transitional Al(OH)3 which may be needed to function as the reactive base, exists IMO and may prevent the formation of the aluminum sulfate from a direct reaction of the soluble alkoxide and the dihydrazine sulfate. The aluminum isopropoxide would I think be fine however for drying the isopropanol and / or stripping the H2O content from an already freebased hydrazine hydrate in solution in the isopropanol, and the insoluble Al(OH)3 byproduct could be filtered leaving the anhydrous hydrazine in anhydrous isopropanol. This would probably be better targeted to a slightly less than anhydrous solution in order to avoid any excess of unreacted aluminum isopropoxide which would then contaminate the azide wished to be produced later as only the sodium salt.

Bearing these two potential complications in mind, it points to sodium ethoxide as the better choice for such a scheme, probably even if it is to be used as the substituted NaOH "base" dissolved in isopropanol, unless a sodium isopropoxide may be formed similarly and as easily as is the sodium ethoxide. The sodium alcoholate is easier to make and requires no distillation.

Sodium ethoxide related reading here
http://www.sciencemadness.org/talk/viewthread.php?tid=17074&...
and here
http://www.sciencemadness.org/talk/viewthread.php?tid=2656

See US1978647 attached.

Continuing with the "brainstorming" on this the aluminum isopropoxide may be useful for preparation of the sodium isopropoxide, simply by reacting with NaOH. Evidently the sodium isopropoxide is much more soluble in the isopropanol than is NaOH so this would address the low solubility issue for NaOH in isopropanol. It is possible and likely the sodium isopropoxide could be used for the base in the nitrosation stage as well. Attached is a product sheet showing sodium isoproxide sold as a 12% solution in isopropanol and what may be its additional solubility I don't know but it is at least 12%.
http://www.sciencemadness.org/talk/viewthread.php?tid=13212&...

Attachment: US1978647 Acetone Precipitation of Sodium Ethoxide.pdf (201kB)
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Attachment: Sodium_Isopropoxide.pdf (74kB)
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[Edited on 3-4-2013 by Rosco Bodine]

A few more dots yet to connect about sodium azide

Rosco Bodine - 3-4-2013 at 12:08

My earlier declaration about having fully connected the dots on the matter of sodium azide synthesis was a bit premature.
It seems there is some more yet to say about this.

Two patents in particular, US1628380 and US5208002 are especially relevant and were mentioned in my first anonymous e-mails to Polverone 10 years ago.

http://www.sciencemadness.org/talk/viewthread.php?tid=470&am...

The later patent represents an improvement over the earlier patent. In the 10 years interim neither patent has been attached until now. Hmmm. Something useful has there been hidden in plain sight, or perhaps overlooked. Compare the two patents and the technical difficulty in particular, for the anhydrous technique which resorts to even use of sodium ethoxide to maintain a low water content and facilitate a more complete reaction and easier isolation of the product in some better yield, but the price paid for that being more difficult manipulations. Obviously the process is still entirely workable even for the reaction system where water content is substantial. Here the more modern patent looks at the economics which arguably show it is easier to simply increase the batch size and use less rigorous conditions to offset any lesser yield, and showing by example 3 that the implementation of the simpler conditions is entirely workable on a lab scale.

US1628380 Azide from hydrazine and organic nitrite via low H2O content reaction system

Attachment: US1628380 Azide from hydrazine and organic nitrite via low H2O content reaction system.pdf (163kB)
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US5208002 Azide from organic nitrite and hydrazine via high H2O content reaction system

Attachment: US5208002 Azide from organic nitrite and hydrazine via high H2O content reaction system.pdf (159kB)
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So there really are 2 entirely valid approaches where the same chemistry applies but the manipulations are easier for the more modern method. It would seem perfectly well adaptable to a dropwise addition of an organic nitrite, and should work with other alcohols as well, even though the quantities may have to be adjusted because the model reaction of example 3 of the patent describes the work using methanol. Refinements would seem possible beyond what the more modern patent describes. I will study this further, to estimate how most conveniently to approach similar reaction system conditions as described for the later patent's less rigorous conditions, having easier manipulations involving the freebasing of hydrazine tolerating a higher level of hydration which evidently poses no obstacle to producing a good yield, but only changes the manipulations involved in isolation of the product, requiring some evaporation and concentration of the completed reaction mixture due to the product azide being in significant amount but not completely dissolved in the completed reaction mixture due to the water content. Dealing with simply concentrating the reaction mixture to crystallize out the dissolved product is a routine manipulation which presents no special difficulty.

http://www.youtube.com/watch?v=lJiznhUEc8g

<iframe sandbox width="640" height="480" src="http://www.youtube.com/embed/lJiznhUEc8g" frameborder="0" allowfullscreen></iframe>

[Edited on 4-4-2013 by Rosco Bodine]

Microtek - 4-4-2013 at 00:36

The point of adding the NaOH in two portions, is that the first formation of the paste of NaHSO4, hydrazine hydrate and alcohol is that the hydroxide does not need to dissolve in the alcohol (at least this is my intuition; I haven't really analysed the reaction to be certain).

Rosco Bodine - 4-4-2013 at 00:53

What is the reason why you think the acid sulfate of sodium is the initial neutralization byproduct? I don't believe that is correct. I believe the byproduct is the normal sulfate ....start to finish. I am pretty certain the dihydrazine sulfate forms progressively as the first half of the base is added by observation of the liquification of half the solids of the slurry, which seems to melt to a thinnest viscosity when fairly hot ~85C est. not measured.

At the half neutralization this is what I think you get

2 NH2NH2-H2SO4 + 2 NaOH ---> (NH2NH2)2-H2SO4 + Na2SO4 + 2 H2O

solubility for monohydrazine sulfate 3.4 g per 100ml H2O @ 25C
solubility for dihydrazine sulfate 202.2 g per 100ml H2O @ 25C freezing point / m.p. 45-55 C

Then during the freebasing stage of the remaining base addition

(NH2NH2)2-H2SO4 + 2 NaOH ----> 2 NH2NH2-H2O + Na2SO4 + ( Na2SO4 + 2 H2O from above )

It was my thought that in the freebasing stage is where it may be an advantage to use 1 mole of Ca(OH)2 in place of the 2 moles of NaOH hoping to form the double salt CaSO4-Na2SO4 via reaction with the Na2SO4 from the first reaction above. The double salt is anhydrous and would not pull water of crystallization which here is mixed with hydrazine hydrate. It was my thought this "glauberite" double salt may be a more dense material and would also reduce any impurity of sodium sulfate in the supernatant aqueous hydrazine hydrate....with or without alcohol. But I think the freebasing using the calcium hydroxide would not be favored by much alcohol because of the low solubility of that base in alcohol and low enough solubility already in H2O which would be worsened by alcohol. The alcohol would be added
after the freebasing is completed to take up the freebased hydrazine hydrate in water which will be the liquid phase of the "glauberite" slurry, extracted using the alcohol swirled with the slurry, and decanted from the solids. I think this would probably work. If not, then we know straight sodium hydroxide works with or without alcohol.

On that you are correct no alcohol is required for the neutralization of monohydrazine sulfate to begin with contact with solid NaOH, a single drop of H2O will cause an exothermic reaction between the solids to initiate and it will continue from its own heat of reaction kicked further by the heat of solution of the solid NaOH dissolving in the byproduct H2O. A large mass of the solids will get really hot really fast in the same way as does solid NaOH react with sulfur and it will form a melted very hot slurry from the exotherm. The heating is so great it could be dangerous with really large batches of several moles. Even with a 2 mole batch a portionwise neutralization approach is what I do because of the exotherm.

[Edited on 4-4-2013 by Rosco Bodine]

Microtek - 4-4-2013 at 04:17

I base my hypothesis on the supposition that the sodium ion essentially would replace the hydrazinium in the mono-hydrazinium sulfate. The reason that I formulated this hypothesis to begin with was because I had observed a very marked difference between the mix at the two points (after the addition of one equivalent and after addition of the second equivalent).
Your hypothesis would explain that as well. I haven't looked at equilibrium constants because, frankly, I was more interested in the fact that it worked than why it worked (though if you wanted to explore the reaction further, the "why" does obviously becomes important).

Rosco Bodine - 4-4-2013 at 08:52

Actually I would amend what I said above about the normal sulfate forming from start to finish. What you are saying about the acid sulfate formation could certainly be mathematically possible for the reaction from the very beginning of the base additions up to the point where 25% of the neutralization occurs, which would be the midpoint of the first half reaction. It was just my first thought that it likely did not happen, but looking at it further it would certainly be possible if the kinetics allow for it. I knew the dihydrazine sulfate formation was what was desired to form and does form completely by the midpoint of the reaction, in either case. But theoretically in the first 25% of the overall neutralization the math does work for the formation of an acid sulfate as a transient intermediate, also having 1 H2O byproduct at that point. In practical terms it really makes no difference to the process by the time the midpoint has been reached, where the acid sulfate would have then been converted to the normal sulfate before the freebasing could begin. but it is an interesting technical detail that the sulfate could initially be the acid sulfate during the first 25% of the overall neutralization. What you are describing would be a two stage reaction leading to the midpoint, with the second reaction below indicating the midpoint of the overall reaction.

2 NH2NH2-H2SO4 + NaOH ---> (NH2NH2)2-H2SO4 + NaHSO4 + 1 H2O ( midpoint of the first half-reaction )

(NH2NH2)2-H2SO4 + NaHSO4 + NaOH ----> (NH2NH2)2-H2SO4 + Na2SO4 + 1 H2O + ( 1 H2O from above )

( midpoint of overall reaction )

Thereafter as per shown earlier:
Then during the freebasing stage of the remaining base addition

(NH2NH2)2-H2SO4 + 2 NaOH ----> 2 NH2NH2-H2O + Na2SO4 + ( Na2SO4 + 2 H2O from above )

The simplified but really oversimplified summary equation which could be wriiten for the reaction overall would be

NH2NH2-H2SO4 + 2 NaOH ----> NH2NH2-H2O + Na2SO4 + H2O

Most people would just look at the summary equation and it does not accurately reflect the stepwise intermediate reactions which are occurring as detailed above. The summary equation only shows the relative proportions of reactants overall, but is deceptive oversimplification about the reaction mechanisms leading to that summary reaction which is not really showing the operative reactions as do actually occur.

It threw me a curve when you mentioned the formation of free hydrazine which certainly can only appear after the midpoint in the reaction, where by that point there could not be any acid sulfate present. Some trace water I think is probably necessary to initiate the reaction which rate increases as a result of its own byproduct water. The water allows dissolution of the solids which being solids are physically separated and isolated but progressively dissolve and react in a local zone of solution that is the liquid phase provided by the small amount of water. Without any solvent, I think the dry reactants would not quickly react at all because the subdivision of the materials is insufficient to bring the reactants into homogenous contact, and the surface reaction limitation aspect would slow or possibly stop the reaction from continuing. The slurry of solid particles dissolving into and byproducts precipitating from the solvent allows the reaction to proceed through the mass of reacting solids. And here the most reaction enabling solvent is necessarily water at least in part, even when alcohol is also an additional solvent.

[Edited on 4-4-2013 by Rosco Bodine]

Microtek - 7-4-2013 at 13:10


Quote:

Some trace water I think is probably necessary to initiate the reaction which rate increases as a result of its own byproduct water. The water allows dissolution of the solids which being solids are physically separated and isolated but progressively dissolve and react in a local zone of solution that is the liquid phase provided by the small amount of water.


Yes, this is what I meant, and also why it is not necessary or desirable to use a large amount of alcohol to dissolve the hydroxide. I believe that the intimate contact between reactants in the slurry that forms until the midpoint is reached allows for a more complete (and faster) reaction than an alcoholic solution of the hydroxide would.

Rosco Bodine - 11-4-2013 at 23:17

Earlier in the thread S.C. Wack posted links for some German publications which may be helpful and I would ask for any German speakers to look at this particularly the patent DE205683

I am curious about the use of ammonium sulfate mentioned in the patent.

If I understand the German patent describes distillation of the product as aqueous hydrazoic acid. Of course, while requiring special technique, distillation would eliminate problems of isolation and purification of the intended product from an aqueous mixture where byproducts are in solution or coprecipitated. Also there are reactions where the recreation of the free hydrazoic acid is done in situ using sodium azide and an acid for further reaction such as with dicyandiamide to produce 5-aminotetrazole, so if this or ammonium azide as two examples were the ultimate intended end product, the process may be adaptable for making use of the distillate directly, or to use its precursor mixture in some alternate scheme.

http://www.sciencemadness.org/talk/viewthread.php?tid=1987&a...

Curtius und Rissom Neue Untersuchungen uber Stickstoffwasserstoff N3H Journal fur praktische Chemie Oct. 1898 (attached)


Attachment: DE205683 Azide patent Stolle.pdf (109kB)
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Attachment: Curtius und Rissom Journal fur praktische Chemie Oct. 1898.pdf (1.8MB)
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[Edited on 12-4-2013 by Rosco Bodine]

Hodgkinson patent related

Rosco Bodine - 12-4-2013 at 01:58

In my first communication 10 years ago I mentioned the Hodgkinson patents, which have been posted about maybe 3 or 4 times since obtaining copies of those patents. GB128014 is still intriguing. Hodgkinson indicates it is a fickle reaction occurring in a very specific narrow range of pH but is somewhat cryptic about giving that pH a number.

http://www.sciencemadness.org/talk/viewthread.php?tid=874&am...

The reaction between an alkali nitrite and the neutral hydrazine salt is described to occur in an only slightly acidic solution not so acidic as to redden litmus which would be a lower limit of 5 pH or perhaps 4.5 pH. Hodgkinson mentions the reaction as comparable to the pH of a solution of boric acid but does not specify the strength of the example solution of boric acid, which even at about half of saturation at room temperature would be on the threshold of being too low pH and would definitely redden litmus. So Hodgkinson is being mysterious while claiming yields of 85% for his mysterious aqueous system process. There are recent patents claiming reaction of free hydrazine and an organic nitrite in an aqueous system in the presence of a base.
And there are some early art references mentioning use of a inorganic nitrite in reaction with a hydrazine salt but the references describe acidic conditions, some of them highly acidic conditions. There appear to be 2 different mechanisms and possibly 3 different mechanisms and the mechanism involving a highly acidic reaction mixture is an oxidation, having about one third of the potential yields of the alternate scheme of nitrosation or diazotization done in an alkaline reaction system. Hodgkinson seems to teach that the nitrosation mechanism will still occur if the reaction system is only very slightly acidic, and does proceed in an aqueous reaction system. The pH range would seem to be in the range of bromocresol green or bromocresol purple or alizarin. Hodgkinson offers no help on process monitoring indicators except for mention of litmus. Hopefully that can be updated to an indicator having a sharp transition for process monitoring any experiments. What coloration may occur in the reaction mixture could be a factor but is unknown.

Hodgkinson is cryptic also about the needed amount of alkali which he supposes must be present to maintain the precise acidity and specific pH for the reaction system. Stoichiometry reveals that a full molar equivalent of NaOH or probably better NaHCO3 would be required along with the NaNO2 in order for the reaction to remain close to neutral. But the description given by Hodgkinson states that the small impurity of alkali expected to be present in the sodium nitrite would provide adequate buffering ....when the reaction stoichiometry does not suggest this would hold true. Hodgkinson hedges his description by conceding that some added amount of alkali may be required if sufficient alkali is not present in the nitrite , when the stoichiometry suggests that such need for additional alkali is a certainty. My own reckoning of what would be needed is an equivalent of NaOH or NaHCO3, and probably what would be more workable still would be some replacement of that equivalent with a not yet predicted but probably small amount of NaOAc which would serve as a buffer to maintain the highly specific pH requirement described by Hodgkinson.

This azide synthesis described by Hodgkinson continues to be intriguing to me, particularly because of the reported high yields from what appears to be a mild reaction condition, but a fickle reaction requiring great precision to accomplish ...IF indeed it works as described or can be made to work by some slight modification of what is described, after ascertaining what little secrets Hodgkinson may not have mentioned while describing the process. I do not think it was just "inventors euphoria" or wishful thinking that would have Hodgkinson apply for 2 patents and associate the invention with the Ordnance College of England, so there is probably some validity to the patent, even though it is clearly NOT a patent which makes "full disclosure" of all the factual particulars in great detail. This leaves the matter art which must be puzzling to more persons than just myself, with regards to ascertaining the full details of precisely how such a reaction must be conducted in order to work as described only generally. I have tried in the past to make this process work and it failed, but I was not observant of the highly specific pH which evidently is THE absolutely imperative requirement.

Studying the reaction and doing experiments possibly could lead to formulating exacting proportions of the required ingredients so that the target pH would be achieved by
buffering and then the process would be reliable and reproducible.

Attached are some related reference materials which may help trying to model the reaction, particularly with regards to the proposed buffering aspect for the nitrite in admixture with NaOH or more likely NaHCO3, and NaOAC which might be required to make the process workable. In place of NaOAC, NH4OAc, borax, or ammonium borate might also be workable as part of the reasonably believed to be required buffering scheme which Hodgkinson neglected to describe in full detail.

One thing of collateral interest which Hodgkinson did describe is the conversion of the slightly soluble hydrazine acid salt to the highly soluble neutral salt. That much is something I and others have confirmed does occur.


Attachment: GB128014 Hodgkinson azide patent 1.pdf (185kB)
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Attachment: NO2 generation by NaNO2 plus Boric Acid solutions.pdf (81kB)
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Attachment: pds-borates-optibor.pdf (88kB)
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Attachment: pds-borates-ammoniumpentaborate.pdf (54kB)
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This would seem to be a likely candidate indicator



Further investigation of the Hodgkinson azide synthesis by experimental modeling and if possible by historical research into the process as conducted looking at any industrial records or additonal writings of Hodgkinson or others employing the process, would make an excellent PhD dissertation and thesis for some graduate student .... you know ...just sayin' this would be a cracker jack good one for some poor soul trying to think up something, anything worthy as a subject for that important research paper.

Nothing like stirring the pot :D Maybe this Hodgkinson azide synthesis will intrigue somebody else as "lost art" which has far too long been missing from the literature and textbooks, seeing that odd omission should be remedied with full disclosure which will remove it from obscurity as lost art, found once again. Now there's a doctoral thesis idea for ya.

Biographical for Hodgkinson
William Richard Eaton Hodgkinson, Ph.D.
(1851–1935)
Professor of Chemistry and Physics, Ordnance College, Woolwich. Cotton Professor of Chemistry and Physics, R.M.A., Woolwich.

FYI & FWIW
http://parazite.nn.fi/roguesci/index.php/t-3211.html
(attached)

Attachment: Azides from Hydrazine Salts GB128014 and GB129152 [Archive] - The Explosives.pdf (28kB)
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Also there was some discussion between myself and PHILOU Zrealone, ( Louis , Ph Z ) at the old alt.engr.explosives news group years ago regarding uncertainties about the Hodgkinson patent which remains mysterious
http://alt.engr.explosives.narkive.com/hUjeaYs1/azides-from-...
(attached)

Attachment: Azides from Hydrazine Salts GB128014.pdf (265kB)
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[Edited on 13-4-2013 by Rosco Bodine]

Hennig Brand - 16-4-2013 at 13:22

When I was discussing dissolving all the hydroxide in the alcohol I was talking about the reaction producing azide not freebasing.

N2H4 + CH3CH(NO2)CH3 + NaOH → NaN3 + CH3CH(OH)CH3 + 2H2O

or

N2H4 + CH3CH(NO2)CH3 + KOH → KN3 + CH3CH(OH)CH3 + 2H2O

I think I am right to dissolve all the hydroxide in the alcohol before adding the nitrite (right?).

Regarding freebasing I also use only a small amount of water (few drops) to start the freebasing. There definitely are two distinctly different products produced during freebasing. IIRC viscous, translucent, gel like material is produced during the first half of the neutralization and then dry crunchy white powder at the end. I always assumed the consensus on the forum was that it was first sodium bisulfate produced and then later sodium sulfate. The mechanism where dihydrazine sulfate is the intermediate could be very useful, if that is what is actually happening.

If the Hodgkinson patent method does work then wouldn't it be a very desirable commercial process? Rosco, you haven't been able to make it work right? I am not saying that it can't work, as I am not an expert, but from my limited experience there is a lot of bull or at the very least inaccuracies in the patent literature.


[Edited on 16-4-2013 by Hennig Brand]

Rosco Bodine - 16-4-2013 at 19:08

Right. I couldn't make the Hodgkinson process work and I definitely tried using careful technique and different approaches and using pH test strips frequently.

I think a variation on what Hodgkinson has described may possibly work but I have not figured it out yet. It is like a rubicks cube, I pick it up and mentally play with it from time to time as a WTF is going on there kind of mental exercise :D I don't like it when a patent stumps me. But some of them do, and this wouldn't be the first to come out of a "war college" laboratory, there was another one called Emmansite IIRC which was actually just picric acid with an HNO3 of crystallization. Similar kinds of cryptic stuff is sprinkled a few places with typographical errors in PATR that have caused perplexing misinterpretations, where the reader must become the proofreader and editor to get the actual facts.

Lately I have been reviewing some of the original and antique literature on azides and will be posting some of it here.

The method which I described for freebasing hydrazine hydrate into methanol, and the variation of Microtek for isopropanol are perfectly valid syntheses for a lab scale sort of "one pot" method. The nearer anhydrous is the reaction system done in alcohol the better will be the yield and simplifies things greatly since it can simply be filtered out of the spent reaction mixture. Towards that end of keeping the final water content minimum I think the best approach is to use the base or the greatest portion of the base in the form of the alcoholate made separately. I believe there may be a lower practical limit for the water content due to at least a tiny portion of water being needed in the freebasing of the hydrazine sulfate.

One of the early researchers Thiele actually performed the reaction of hydrazine and ethyl nitrite using sodium methylate as the base and dehydrating agent, both in excess with respect to hydrazine, and the reaction solvent being ether, Thiele obtained approximately quantitative yield based upon the hydrazine. So this pretty well proves that for a one pot and single pass method, the "dry solvent" approach works for ether or alcohol.



The disadvantage of the aqueous system methods is needing to recycle unreacted materials, and having a heavy mixture of byproducts requiring some scheme for separation, which presents isolation difficulties. Even for the aqueous system methods, in contrast with Hodgkinson other investigators report that the organic nitrite ester and a basic reaction system provides a more rapid reaction and better yield than the alternative which Hodgkinson describes incompletely, and that finding by others makes Hodgkinson even more doubtful.

I think the benefit of Hodgkinson is that some of the things suggested there may have validity ...and usefulness but in other context...so you can make use of those parts, while thinking about the rest as dubious. Hodgkinson was getting on up in years ( 67 ) when the azide patents were published, so there may be some sense of humor injected by the old man into those patents, the kind of humor that might arise with some senility :) Old Ph.D's don't go nutters with age, they only become "eccentric" :D

Much of the German is understandable from recognizing the chemistry, but any help with actual translation to English of these articles is welcome and appreciated.

Zur Darstellung der Stickstoffwasserstoffsaure
Johannes Thiele
Berichte der deutschen chemischen Gesellschaft
Volume 41, Issue 2, pages 2681–2683, Mai–August 1908
(attached)
Attachment: Thiele Berichte.pdf (175kB)
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Uber die Einwirkung von Salpetrigsaureestern auf Hydrazin, Phenylhydrazin und Benzhydrazid in alkalischer Losung
R. Stolle
Berichte der deutschen chemischen Gesellschaft
Volume 41, Issue 2, pages 2811–2813, Mai–August 1908
(attached)
Attachment: Stolle Berichte.pdf (161kB)
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Also here is an older article by Curtius which is more general about azides
Attachment: Curtius Journal_of_the_Switchmen_s_Union.pdf (691kB)
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[Edited on 17-4-2013 by Rosco Bodine]

DE205683 Translation to English

Rosco Bodine - 16-4-2013 at 19:32

Thanks to DerAlte for translation assistance. I think this is pretty accurate but welcome any input from German speakers also understanding the chemistry. The claims part is not included.

DE205683 Translation to English of Stolle azide patent

The reaction of nitrous acid with hydrazine gives hydrazoic acid in a known fashion. However, the yield of this compound is only small. It is now found that HN3 is accessible from easily gotten Hydrazine hydrate or salts when one treats these compounds with nitrous acid ester, such as amyl nitrite or ethyl nitrite, from nitrous acid and the alcohol, in alkaline solution (alcoholate, hydroxide, etc.) in appropriate solvents. Thus one obtains up to 80% yield when one heats hydrazine hydrate in alcoholic solution with amyl nitrite and sodium methylate under reflux.

Otherwise it suffices to shake for a long time hydrazine sulphate with potassium hydroxide with added water, and adding to this solution some alcohol and amyl nitrite. To isolate the resulting hydrazoic acid from the reaction products, the alcohol is distilled off , excess amyl nitrite and amyl alcohol was blown off by steam and thereupon the alkaline solution distilled with appropriate amounts of ammonium sulphate and sulfuric acid. The addition of ammonium sulphate avoids decomposition of HN3 by HNO2 (caused by amyl nitrite derived alkaline nitrite from its saponification, then freed by sulfuric acid) and thus to prevent a loss.

Examples:

[1] Hydrazine hydrate 1kg was heated 25 hours with 4 kg amyl nitrite and a solution of 3 kg KOH in 15 kg alcohol the alcohol distilled off, the amyl alcohol removed by steam distillation, the residue made up with 10 liters water solution and heated with about 3kg ammonium sulphate for 3 hrs, 1 kg sulphuric acid added and distilled. Yield, 70-80% of theoretical (~640 g HN3)

[2] 1 kg hydrazine sulphate, 1 kg KOH, in 2 liters H2O were stirred for 5 hrs, with 4 liters alcohol 1 kg KOH and 1.5 kg amyl nitrite added and stirred or shaken for 40 hours the alcohol distilled off, 0.75 kg ammonium sulphate added, the alcohol then steam distilled off, 5 liters H2O added, and 0.5 kg sulphuric acid, and distilled. Yield 60-70% theoretical about 220 g HN3)

[3] 1 kg hydrazine sulphate 1 kg KOH 4 liters H2O stirred or shaken 5 hrs, 1 kg KOH and 2 kg amyl nitrite added, shaken or stirred for 100 hrs, the amyl alcohol steam distilled off, residue heated 3 hrs with 0.75 kg ammonium sulphate, mixed with 5 liters H2O, and 0.5 kg H2SO4 added and distilled. Yield 40-60% theoretical about 200 g HN3.


Attachment: Translation of DE205683 Stolle Azide patent.pdf (9kB)
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[Edited on 17-4-2013 by Rosco Bodine]

Possible novel variation on Hodgkinson

Rosco Bodine - 20-4-2013 at 12:49

The conditions which are described by Hodgkinson seem possibly adaptable and applicable to use of different reagents in a similar reaction scheme, which I am uncertain will work. The variation which I have contemplated involves addition of isopropyl nitrite to an aqueous solution of acetone azine, with the expectation that the organic nitrite will react with free hydrazine present from hydrolysis of the acetone azine to produce hydrazoic acid, with a specific pH being maintained by concurrent addition of a base, perhaps sodium bicarbonate or ammonium bicarbonate or their respective acetates in some combined buffer scheme. I believe that within a very specific and narrow range of pH that a similar reaction scheme as described by Hodgkinson may occur and if workable would have advantages particularly in excluding unwanted byproducts.

Theory / Hypothesis / Experimental : When the dimethylketazine is dissolved in water, there is sufficient hydrolysis to cause the solution to become basic due to the presence of free hydrazine as the hydrate with 2 molecules of byproduct ketone, in this case acetone, which results in a quaternary system in hydrolytic equilibrium, consisting of hydrazine hydrate, water, and acetone, along with unhydrolyzed dimethylketazine. When isopropyl nitrite is added to the alkaline system it should react with the hydrazine hydrate to form hydrazoic acid, and this will have the effect of lowering the pH which favors further hydrolysis of the reserve lode of dimethylketazine, producing more hydrazine hydrate for further reaction with incoming isopropyl nitrite. In the slightly alkaline pH range is where the reaction would be anticipated to proceed as described, where the hydrazine would be present as the freebase hydrate, reactive with the isopropyl nitrite. The natural tendency of the reaction would be to become increasingly acid from the hydrazoic acid, which would tend to interfere with the desired reaction, unless there is additional base added concurently along with the isopropyl nitrite to neutralize the hydrazoic acid and maintain the slightly alkaline pH. If the pH were allowed to go too far acidic it would tend to quench the desired reaction, because free hydrazine would itself act as a base to neutralize the hydrazoic acid forming hydrazine azide, and another issue would arise with reactivity of the isopropyl nitrite with the acetone as in the acidic condition the hydrazine would compete to be nitrosated, while nitrosation of the acetone would be favored in the acidic reaction mixture. Even though the reaction may be quenched by insufficient neutralizing, it should recover and proceed when the pH is raised again into the operative range of alkalinity. The only foreseeable issue for improper buffering is that some undesired byproduct may occur for the nitrosation of acetone which had not been avoided by allowing pH to transiently range too low, but there would be no hydrazine loss and only a wastage of isopropyl nitrite as the consequence. The reaction should be manageable using a color pH indicator dye, and pacing the additions of isopropyl nitrite and neutralizing base solution at a metered rate which keeps the pH in the desired range of slightly alkaline. This is completely hypothetical, and has not been tested, nor can I find anything in the literature for guidance. However, it seems that the natural hydrolysis of the dimethylketazine could be exploited as described to form an azide, as the sole non volatile product, if the reaction proceeds in the correct pH range. If this hypothetical reaction proceeds with sufficient velocity is a big unknown, and if it will work at all as anticipated is also unknown. It may work fine or not at all.
It seems like it would work. So that makes this hypothetical experiment intriguing, especially if it is novel, when it doesn't seem like somebody else should not have thought of this possible? reaction before. I would have looked it up in the "Journal of Experiments that Seemed like they might work but Failed" but I haven't been able to locate that huge compendium encyclopedic work anywhere. :D

An interesting observation which I would make is that dimethylketazine could find usefulness as a sort of buffer in the orginal Hodgkinson reaction scheme using a neutral hydrazine salt being gradually reacted with an alkali nitrite, because as that reaction becomes acidic it would tend to tie up the hydrazine and quench the reaction, but the presence of dimethylketazine would tend to regulate that falling pH by additional hydrazine being freed by the increasing acidity due to hydrolysis of the dimethylketazine. This suggests it may be possible that both the original Hodgkinson reaction scheme, and the variation contemplated using dimethylketazine as the hydrazine source, might be possible to carried out in mixture as a system, where the kinetics would favor the formation of azide.

For a possible color pH indicator I am thinking bromothymol blue would be about right




Thanks to gsd for the following article (attached)
STUDIES ON HYDRAZINE. THE HYDROLYSIS OF DIMETHYLKETAZINE AND THE EQUILIBRIUM BETWEEN HYDRAZINE AND ACETONE
E. C. Gilbert
J. Am. Chem. Soc., 1929, 51 (11), pp 3394–3409
DOI: 10.1021/ja01386a032
Publication Date: November 1929



Attachment: STUDIES ON HYDRAZINE.pdf (933kB)
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[Edited on 21-4-2013 by Rosco Bodine]

plante1999 - 21-4-2013 at 14:33

Today I made a very tiny amount of silver azide, mostly to test my newly made hydrazine sulphate. I made a 50 ml solution of silver nitrite at 60 C and mixed it with 30 ml of a dilute hydrazine sulphate solution. After a minute, a flocculent precipitate formed. I filtered and too a very tiny sample of the wet azide on a steel sheet. Maybe a mg. Then I lets it dry, and heated with a match. I eard a very loud pop sound. I was amazed by the sound made from a such tiny amount of material. I then poured hot sodium nitrite solution on the azide to decompose it, washed all my glass and stored them.

Hopefully this is of interest to someone.

Bot0nist - 22-4-2013 at 08:16

Nice! Its is quite powerfull, huh? EM makes me nervous. I biult a steel impact test mechanism, and am always startled by how loud just a few mg of sensitive HE is. really puts it in perspective...

hydrazidocarbamoyl azide / hydrazodicarbonazide / Hydrazinodicarbonic Acid Diazide

Rosco Bodine - 22-4-2013 at 13:52

Here's an obscure "carbonic" azide that would seem to qualify as a "green initiator" known by three slightly different names. Searches for this compound turn up very little information.

hydrazidocarbamoyl azide / hydrazodicarbonazide / Hydrazinodicarbonic Acid Diazide

Also described on page 2 of the pdf Carbamoyl Azides (attached)


Attachment: Hydrazinodicarbonic Acid Diazide page 208 Vol 7 H-L PATR.pdf (74kB)
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Attachment: Carbamoyl Azides.pdf (709kB)
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plante1999 - 22-4-2013 at 14:39

Quote: Originally posted by Bot0nist  
Nice! Its is quite powerfull, huh? EM makes me nervous. I biult a steel impact test mechanism, and am always startled by how loud just a few mg of sensitive HE is. really puts it in perspective...


Well, it was only to test the hydrazine sulphate, but yea, very powerful. I'm not interested in EM tough. I don't really understand the interest ether.

more regarding Biurea / hydrazodicarbonamide

Rosco Bodine - 22-4-2013 at 17:20

Other references are found regarding the use of Biurea as a precursor for azides, and oxidation by hypochlorite is one method. Nitrosation by HNO2 is another. Carbamoyl azide is an intermediate product which is further hydrolyzed to hydrazoic acid. This is interesting because it occurs the hypochlorite oxidation occurs in a reaction system that is alkaline, which increases the solubility of the biurea, and which favors hydrolysis of the carbamoyl azide, and which favors neutralization of the hydrazoic acid as either its sodium or ammonium salt. Urea is a byproduct of the hydrolysis of the carbamoyl azide. The nitrosation of the biurea in aqueous NaOH may also be possible using isopropyl nitrite, although no references for this have been found.

(from earlier discussion, related)
http://www.sciencemadness.org/talk/viewthread.php?tid=1987&a...

http://www.sciencemadness.org/talk/viewthread.php?tid=6729&a...





Attachment: Darapsky Journal fur praktische Chemie.pdf (1.6MB)
This file has been downloaded 460 times

[Edited on 23-4-2013 by Rosco Bodine]

Rosco Bodine - 23-4-2013 at 17:36

Quote: Originally posted by plante1999  
Today I made a very tiny amount of silver azide, mostly to test my newly made hydrazine sulphate. I made a 50 ml solution of silver nitrite at 60 C and mixed it with 30 ml of a dilute hydrazine sulphate solution. After a minute, a flocculent precipitate formed. I filtered and too a very tiny sample of the wet azide on a steel sheet. Maybe a mg. Then I lets it dry, and heated with a match. I eard a very loud pop sound. I was amazed by the sound made from a such tiny amount of material. I then poured hot sodium nitrite solution on the azide to decompose it, washed all my glass and stored them.

Hopefully this is of interest to someone.


For historical reference, the experiment you describe was reported by an Italian chemist Angeli 120 years ago.

Attachment: Angeli Silver Azide Ber., 26, 1893.pdf (307kB)
This file has been downloaded 416 times

http://www.youtube.com/watch?v=KShGGElRsxU

<iframe sandbox width="640" height="480" src="http://www.youtube.com/embed/KShGGElRsxU" frameborder="0" allowfullscreen></iframe>

[Edited on 24-4-2013 by Rosco Bodine]

Rosco Bodine - 24-4-2013 at 12:40

Mentioned earlier in the thread is a book
Organic Azides Syntheses and Applications ( Wiley 2010 )

The 11 Mb file is too large for a single attachment so I have split the file into 7 numbered parts as attachments for this post and a subsequent post which you may merge to recompile the book.

Here are the first 4 parts

Attachment: Part 1 Organic Azides Syntheses and Applications Wiley 2010.pdf (1.8MB)
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Attachment: Part 2 Organic Azides Syntheses and Applications Wiley 2010.pdf (1.7MB)
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Attachment: Part 3 Organic Azides Syntheses and Applications Wiley 2010.pdf (1.8MB)
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Attachment: Part 4 Organic Azides Syntheses and Applications Wiley 2010.pdf (1.9MB)
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Rosco Bodine - 24-4-2013 at 12:42

Mentioned earlier in the thread is a book
Organic Azides Syntheses and Applications ( Wiley 2010 )

The 11 Mb file is too large for a single attachment so I have split the file into 7 numbered parts as attachments for this post and the preceding post which you may merge to recompile the book.

Here are the final 3 parts

Attachment: Part 5 Organic Azides Syntheses and Applications Wiley 2010.pdf (1.9MB)
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Attachment: Part 6 Organic Azides Syntheses and Applications Wiley 2010.pdf (1.8MB)
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Attachment: Part 7 Organic Azides Syntheses and Applications Wiley 2010.pdf (824kB)
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http://www.youtube.com/watch?v=TJKu0yShERQ

<iframe sandbox width="640" height="480" src="http://www.youtube.com/embed/TJKu0yShERQ" frameborder="0" allowfullscreen></iframe>

[Edited on 24-4-2013 by Rosco Bodine]

Inorganic Azides

Rosco Bodine - 25-4-2013 at 00:44

Inorganic Azides Solubility Chart


Hydrazoic Acid and Its Inorganic Derivatives.
L. F. Audrieth
Chem. Rev., 1934, 15 (2), pp 169–224
(attached)

Synthesis 26 and 27 from Inorganic Syntheses Vol. 1 (attached)

Synthesis 40 from Inorganic Syntheses Vol. 2 (attached)

Energetic Materials Physics and Chemistry of the Inorganic Azides, Fair (attached)

Attachment: Hydrazoic Acid and Its Inorganic Derivatives Audrieth Chem. Rev. 1934.pdf (812kB)
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Attachment: Synthesis 26 and 27 from Inorganic Synthesis - Volume 1.pdf (538kB)
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Attachment: Synthesis 40 from Inorganic Synthesis - Volume 2.pdf (472kB)
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Attachment: Energetic Materials Physics and Chemistry of the Inorganic Azides, Fair.pdf (1.2MB)
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[Edited on 25-4-2013 by Rosco Bodine]

Staudinger Azide Patent DE273667

Rosco Bodine - 26-4-2013 at 10:49

Here is an interesting idea related to the patent DE273667 which describes use of a nitrosamine as the reagent for diazotization / nitrosation of hydrazine to form an azide.

http://www.sciencemadness.org/talk/viewthread.php?tid=3453&a...

Thanks to Boffis for translation of the Staudinger Azide patent. I changed the formatting slightly to fit it on a single page and made a pdf for it too. (attached)

Urbanski 3 has a writeup on R-salt that provides useful information about the hydrolytic properties (attached)

Here also is an R-salt synthesis which I am not certain but I don't recall being posted before. From Journal of the Chemical Society 1889.



This idea of possible usefulness of R-salt as a nitrosation reagent is not a new idea for me. On the preceding page where I was mentioning again the Hodgkinson patent
http://www.sciencemadness.org/talk/viewthread.php?tid=1987&a...
towards the bottom of that post I mentioned a discussion a decade ago at the old newsgroup alt.engr.explosives, and linked a part of that discussion which was much more extensive. Near the very end of that thread I brought up the Staudinger patent which I referenced by the patent number and the use of a nitrosamine, and speculated that R-salt may also work. So this is a review here a decade later with additional references and translations for benefit. Here I will link that old newsgroup conversation, which was mostly between PHILOU Zrealone and myself. The relevant post is the third post up from the bottom of the page
http://alt.engr.explosives.narkive.com/sJmT2yCp/interesting-...
An excerpt pdf showing the relevant post is attached.
So this discussion and review of azides has come full circle over 10 years. There's the deja vu. There is no "re" in research without a little deja vu.

Attachment: DE273667 Staudinger Azide from nitrosamine and hydrazine patent.pdf (104kB)
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Attachment: R-salt preparation JCS.pdf (164kB)
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Attachment: German Patent 273667 A method for producing hydrazoic acid or azide salts.pdf (45kB)
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Attachment: Nitrosamine pages from Urbanski 3.pdf (273kB)
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Attachment: excerpt from Interesting Azide Patents ( circa 1919 ) - page 5.pdf (18kB)
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http://www.youtube.com/watch?v=LjRuVehaXJ4

<iframe sandbox width="640" height="480" src="http://www.youtube.com/embed/LjRuVehaXJ4" frameborder="0" allowfullscreen></iframe>

[Edited on 27-4-2013 by Rosco Bodine]

pjig - 29-4-2013 at 21:08

Dang That is a nice line up of useful material. Thanks for that Rosco

*One question in regards to the disposal of waste liquor : From reading Urbanski 3, I found that it is the practice to use a sol. of 15%Hno3 and 8%Nano2 to destroy the remaining azides . What is a good way of knowing if you effectively neutralized the waste ? Assuming the mother liquor was 400ml in total (the final azide produced was 5g). The wash water and dextrinated wash would be included in this to add another 400ml approx . totaling 800ml of waste water.

*Another thought concerning Agn3. ; My understandings are that it is NOT practice to recrystallize azides to purify them( due to the dangerous formation of large crystals), mostly LA. Is this danger the same for Agn3? Urbanski stated that Agn3 is soluble in ammonia. If Agn3 was to be brought into sol. of ammonia and recrystallized, would it become a double salt of both ammonium/silver azide? OR, would the Agn3 recrystallize into a larger crystal formation ( could this be avoided by a cool re-crystallization of the product.)?

Rosco Bodine - 30-4-2013 at 02:02

Yeah I was hoping to find and share something useful, but am not sure if any of these references may lead to anything new. I suspect a lot of experimentation is probably already done which didn't produce any impressive yields and those experiments were never published or are buried in obscurity. There is always a chance of finding something new or getting new ideas by reviewing the old references.

Sodium azide is biodegradable and has been used as a soil fumigant for weed and nematode control as a substitute for methyl bromide. AgN3 is reportedly more sensitive than silver fulminate, and has only found use in some specialized micronized particulate "colloidal" form, and even then is still sensitive. Many references say AgN3 is treacherous, which reminds me of the similar language for copper and cadmium azides. The lead salt and its composites still rule in terms of practicality and economy and performance.

The possibility of using nitrosamines to perform the diazotization, and the use of alternative "donors" for the hydrazine function just seemed to open up possibilities for an aqueous reaction system method to be devised, and this idea has always been intriguing as a potential simplification. Not only could R-salt be a potential candidate but DNPT might also work. Anyway it is good to find some ideas for experiments which have some promise and yet are not reported.

Using methanol or isopropanol or ethanol as a solvent extraction for the hydrazine hydrate, basified with either NaOH or KOH or an alcoholate, and then treating with an organic nitrite ester is a proven approach. But it is likely that an aqueous reaction system scheme with reasonable efficiency can be found, and that is mainly what I have been interested in finding or devising. It is a tough nut to crack.

[Edited on 30-4-2013 by Rosco Bodine]

pjig - 30-4-2013 at 07:15

Tough nut to crack is right. ;)

They are a intriguing field to study, and provide unique initiating property's .
You comment about the sensitivity of Agn3, was it related to impact, friction, of photo-sensitivities? It was my understanding it is almost par with LA in power and less sensitive to the hammer drop. Urbanski #3 /pg #184 last paragraphs : state the Agn3 is less sensitive to the drop v.s LA. Also the hammer drop needed to initiate is 5x more than Merc-Fulm.
My assumption is the photo sensitivities you speak of in terms of dangers . I dont recall however finding the friction ratings of the material in comparison. Do you have some references to this aside from urbanski?

Also, Is the sol. of hno3, and Nano2 only needed in small amounts to kill the azide left in the waste wash? I was assuming that a 100ml sol. of 15% hno3, 8%nano2 would be more than effective to make the waste liquor(800ml) safe to dispose of . Is this a fair assumption ?
Also thanks for the in-site on the Nan3 being a fumigant for soils , I wasnt aware of that . good to know , though.:cool:

[Edited on 30-4-2013 by pjig]

pjig - 30-4-2013 at 07:44

I guess it is the sensitivities to friction that make it more of a danger to work with.


PATR2700 Vol 1 /pg# A598
Explosion Temperature, 0 C. 297° in 5 sec
for a 0.02g sample (Ref 15) to 308° in 1 sec
for a 0.02 g sample (Ref 58)
Friction Sensitivity, extremely sens, but
more stable to friction than either Cu, Ni or
Co azides (Ref 15) (also see Ref 28)
Impact Sensitivity, 3 in with 2 kg wt and 6
cm with 1 kg wt or 41 cm with 500 g Wt vs
43 cm for LA both in BM App (Refs 28&,58)
Initiating Efficiency, see table under Mercutous
Azide (or Ref 16)
Lead Block Expansion, 22.6 cc for 2g sample
vs 25.6 cc for MF(Ref 9, p 247)
Stability, color remains white when kept in
the dark but on exposure to sunlight crystals
darken. It is stable at 75° (Refs 28& 46)
Temperature Developed on Explosion 3545°
vs 3420° for LA(Ref 16)

DubaiAmateurRocketry - 10-6-2013 at 22:53

Azide's decomposition is exothermic right ?

Since like, example 2NaN3 > 2Na + 3N2 , the tripple N2 bonds release more energy than the doubble ones in NaN3, so is it exothermic ? or the ionic energy breaking need a lot of energy ?

DubaiAmateurRocketry - 12-6-2013 at 00:27

And do u have information for Lithium Azide on ur book ?

pjig - 22-6-2013 at 21:44


Patr pg. a588

Lithium Azide (formerly called Lithium
Azoimide or Lithium Trinitride), LiN3, mw
48.96, N85. 83%; anisotropic, CO1 crysts, mp expl
115° to 29@ (Ref 1); sol in w (36. 1% at
10° and 66.4% at 160), sol in alc (20.3% at
16°) and insol in eth (Ref 1); Q? -2.58 kc~/
mol at 298°K, lattice energy 194 kcal/mol
at 298”K (Ref 21). Prepd in 1898 by Curtius
& Rissom (Ref 1) by the action of a soln of
lithium sulfate on barium azide and evapn of
the clear liq.

Explosive Properties. Li azide, although
detond with difficulty, propagates at a
velocity of 990 m/see (Ref 15). Wohler &
Martin (Ref 5) obtd an expln temp of 245°
for 0.02 g of the subst which detond violently
after 5 sec, but this compd could not be
detond by impact.

AndersHoveland - 23-6-2013 at 03:53

Lithium azide has only moderate explosive properties. Decomposition of lithium azide only forms lithium nitride and nitrogen. It can survive hammer blows without detonation

Sodium azide is not itself an explosive. The main reason for this is rather simple- the decomposition proceeds according to the following equation:
2 NaN3 --> 2 Na + 3 N2
The reduction of sodium ions to elemental sodium is not particularly favorable, and this is one of the main reasons sodium azide is not explosive. Sodium nitride does not form because Na3N is not very stable (sodium nitride decomposes into its elements at only 87 °C ).

Calcium azide begins to thermally decompose above 110 °C, and explodes at 158°, it is more explosive than either strontium or barium azide.

Barium azide is a sensitive explosive, with a drop height value of 10cm. It appears to be relatively insensitive to impact but highly sensitive to friction. H. Ficheroulle, Mem. des Poudres. 33, 7 (1956)
The temperature at which barium azide explodes is apparently highly variable, values have been reported between 152° to 221°C.
The enthalpy of formation for barium azide from its elements is actually slightly negative, -5.3 kcal/mole. The formation of barium nitride is very favorable, the compound having an enthalpy of formation of -89.9 kcal/mole. "Nitrogen Burning of Metals", G. Petrov, Combustion, Explosion, and Shock Waves, Volume 11, Number 3, 309-312
The decomposition products from the explosion of barium azide leave behind a significant quantity of metallic barium, whereas the explosion of calcium azide leaves only calcium nitride.

[Edited on 23-6-2013 by AndersHoveland]

DubaiAmateurRocketry - 24-6-2013 at 08:22

Wow thanks.

What about Magnesium azide ? does aluminum or titanium azides exist ? if so may i know little about it :) I think elemental is good.

If lithium azide was elemental decomposition, it would have been great, lithium alone could have burned by oxygen to form the second most exothermic reaction in all of chemistry :)

DubaiAmateurRocketry - 26-6-2013 at 11:39

can someone reply ^

hyfalcon - 26-6-2013 at 11:50

http://magnesium.atomistry.com/magnesium_azide.html

http://pubs.acs.org/doi/abs/10.1021/ic9614834

I found these two references with a minimal search. Dig a little harder.

Rosco Bodine - 2-9-2013 at 19:28

Technology of the Inorganic Azides, Energetic Materials Vol. 2, Fair

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&a...

Rosco Bodine - 4-9-2013 at 08:47

Primary Explosives

http://www.mediafire.com/download/9fzstasacfqrato/Primary+Ex...

You may also like this

High Energy Materials, Agrawal, Wiley

http://f3.tiera.ru/2/Ch_Chemistry/Agrawal%20J.P.%20High%20En...


Here is an interesting Russian site
http://www.exploders.us/sprawka/26.html

Google translation link
http://translate.google.com/translate?hl=en&sl=ru&u=...

And a Google translation of the lead azide section is attached. The validity of the translation and the validity of the described processes is not verified.

Attachment: translation lead azide.pdf (17kB)
This file has been downloaded 1432 times

[Edited on 5-9-2013 by Rosco Bodine]

memo for Dr. Klapoetke and his team

Rosco Bodine - 23-9-2013 at 08:22

Quote: Originally posted by Rosco Bodine  
Here's an obscure "carbonic" azide that would seem to qualify as a "green initiator" known by three slightly different names. Searches for this compound turn up very little information.

hydrazidocarbamoyl azide / hydrazodicarbonazide / Hydrazinodicarbonic Acid Diazide

Also described on page 2 of the pdf Carbamoyl Azides (attached)


In addition to the above compound with references linked in the post earlier in this thread
http://www.sciencemadness.org/talk/viewthread.php?tid=1987&a...

There is mentioned earlier in the literature a diazonium salt of carbamoyl azide obtained by nitrosation of carbamoyl azide. It is compound IIIc on page 385 of the following article attached below.

Über die Ultraviolett-Absorption und Konstitution von Tetrazenen aus Aminoguanidinsalzen
Ruth Hofsommer, Max Pestemer

Zeitschrift für Elektrochemie und angewandte physikalische Chemie
Volume 53, Issue 6, pages 383–387, Dezember 1949

This diazonium salt of carbamoyl azide IIIc is a monobasic cation which could also form salts different from the identified chloride, and salts such as the picrate or styphnate or nitrate or perchlorate may be possible and may be interesting, as well as salts with various tetrazoles.

Additional context is provided by the following article attached.

Ueber das sogenannte Diazoguanidin
A. Hantzsch, A. Vagt
Justus Liebigs Annalen der Chemie
Volume 314, Issue 3, pages 339–369, 1901

On page 368 next to the last page in the lower chart on the bottom left is a "missing compound" as would correspond with the chart in the section above, and it would seem that this missing element would be occupied by the compound IIIc, as a variant alternative outcome.

What is the stability of the diazonium salt of carbamoyl azide and if it is sufficient to provide any practical usefulness for any derivatives is unknown. Also unknown is whether further investigation of this potential energetic compound has already been done.

Attachment: Carbamyl Azide 70 per cent yield from Semicarbazide Hofsommer and Pestemer article.pdf (518kB)
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Attachment: A. Hantzsch, A. Vagt, Annalen 314, 3, 339-369.pdf (1.1MB)
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https://www.youtube.com/watch?v=HSgVcNEUEPc

<iframe sandbox width="640" height="480" src="//www.youtube.com/embed/HSgVcNEUEPc?rel=0" frameborder="0" allowfullscreen></iframe>

https://www.youtube.com/watch?v=opleOxh0W_0

<iframe sandbox width="640" height="480" src="//www.youtube.com/embed/opleOxh0W_0?rel=0" frameborder="0" allowfullscreen></iframe>

[Edited on 23-9-2013 by Rosco Bodine]

bismuthate - 17-10-2013 at 14:27

Could I please get some information on bismuth triazide I could only find a paragraph about it. For example I know that it forms complexs however I haven't found out what it will Form a complex with.
I wonder if anyone has ever been brave (or stupid) enough to make polonium azide.

[Edited on 17-10-2013 by bismuthate]

Rosco Bodine - 17-10-2013 at 20:11

Quote: Originally posted by bismuthate  
Could I please get some information on bismuth triazide I could only find a paragraph about it. For example I know that it forms complexs however I haven't found out what it will Form a complex with.
I wonder if anyone has ever been brave (or stupid) enough to make polonium azide.


The likely starting point for an attempted synthesis of Bismuth Azide would be to dissolve Bismuth Nitrate in a moderately strong solution of Mannitol and react by a gradual addition of sodium azide. Alternatively a solution of Bismuth Citrate in Ammonium Hydroxide could be used for the Bismuth value, but the basic solution would be more likely to precipiatate the basic azide. The first approach using the chelation by mannitol to form a neutral solution of the soluble bismuth is a possibility as a best guess starting point. It may be that the bismuth azide is simply not stable and doesn't form at all. PATR mentions a possible iodine complex of bismuth azide, so a concurrent drip of iodine solution might be the next step if the normal or basic azide doesn't result from the mannitol chelated soluble neutral bismuth nitrate precursor solution on reaction with sodium azide. This is an unknown and experimental procedure about which I am speculating so due caution should be used in any experiments for not knowing exactly what to expect.

bismuthate - 18-10-2013 at 02:37

Thanks! That was very interesting I think I will try to synthesize it as soon as I get some sodium azide. Also bismuth has a tendencey to make oxy-halogen compoung, so since the azide ion is pseudohalogen I wonder if there is an oxyazide.

Dany - 18-10-2013 at 03:19

Here's a paper in Angewandt chemie on the synthesis of 3 derivatives of bismuth azide. Be carefull Bi(N3)3 is shock sensitive explosive. it detonate @ 154°C releasing a green cloud of smoke.

the second attachement is a paper in Inorganic chemistry journal on an alternative synthesis of Bi(N3)3 along with a structural study on this compounds and it's solvate.

Dany.

Attachment: Binary Bismuth(III) Azides- Bi(N3)3 , [Bi(N3)4]−, and [Bi(N3)6]3−.pdf (373kB)
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[Edited on 18-10-2013 by Dany]

Attachment: Solid State Structure of Bi(N3)3.pdf.pdf (1.9MB)
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bismuthate - 18-10-2013 at 03:28

Thank you I saw that paper but I couldn't get ascess. Thaks again I realy wanted to read that. Green smoke that sounds amazing.
P.S. I found that the same journal has many other azide articles I should subscribe.

[Edited on 18-10-2013 by bismuthate]

Azides from secondary nitrosamines

Boffis - 17-11-2013 at 10:16

Following Rosco's introduction the Staudinger patent posted above (original and translation) and Rosco suggestion (in a U2U) that this might work with Nitroso-R-salt (C.T.M.T.N.A) I thought I would give it a try with various nitrosamines. The following notes are just provisional results and I will report full experiment details when I have completed the work after Christmas.

With R-salt ammonia was released over about 6 hours of refluxing of the reactants in methanol but no precipitate of K azide occurred; only a brown homogenous solution resulted which did not deposit crystals even after 24hrs in the fridge. I used potassium hydroxide as the base, it is soluble in methanol but the azide should not be appreciably so (see data earlier in this post). After 6 hours I distilled off 70% of the original methanol and neutralised the solution with 4M nitric acid to pH7; much precipitate formed but after washing with methanol the white solid proved to be KNO3: no surprises there!

A little of the brown solution that was left was treated with lead acetate solution, a small amount of pale brown precipitate formed, it was weakly energetic but the substance is clearly not Pb azide.

With dimethylamine the initial nitrosamine is water soluble so I extracted it with ether and removed the ether on a warm water bath and then proceeded as before but using water as the solvent with the intention of ppt the azide with Pb acetate but again only a trace of weakly energetic salt precipitated though a yellow oil formed on the surface that would not crystallise.

I have saved the products and will investigate them further when I have time.

I have yet to try the reaction as described by Staudinger with diphenyl nitrosamine.

An interesting thought concerns the fate of the of the liberated sym-triazine. Staudinger states that with diphenylnitrosamine the liberated diphenylamine can be recovered and re-used. Is the liberated triazine from R-salt likewise stable enough to be recovered and how soluble is it in methanol? The liberation of ammonia suggested that it maybe broken down to ammonia and formaldehyde. Another possible reaction is the simple reduction of the nitroso moiety to an amine, but this reaction would liberate nitrogen and I found the liberated gas to be highly soluble in water (ammonia could be smelt but I can't rule out the presence of formaldehyde but in the strongly alkaline solution the latter may be destroyed as fast as it is formed).

So... the initial results don't look too promising but I haven't tried Staudinger original method yet.

[Edited on 17-11-2013 by Boffis]

Rosco Bodine - 18-11-2013 at 01:35

Urbanski reported the decomposition of R-salt by NaOH slowly in the cold and rapidly when heated, with formaldehyde, ammonia, and nitrogen produced.

Before ruling out this potential method it should be tested what is the result for Dinitrosopentamethylenetetramine with the methanolic hydrazine and possibly in the alternative using calcium hydroxide as the base, seeking calcium azide as the intermediate product.

Dinitrosopentamethylenetetramine gives the same positive Liebermann's nitroso reaction test as does diphenylnitrosamine of the Staudinger patent, and I'm not sure if R-salt does give the same positive reaction. I thought it did but I'll have to double check. I'm thinking the R-salt may be sensitive to the high pH of the more caustic soluble alkali base and the dinitroso compound may have better stability and less degradation by calcium hydroxide which would be a low soluble in the methanol, but would neutralize any free HN3 and gradually go into solution as the azide. The solution could later be made moist with some H2O and tested for reaction with sodium bicarbonate solution added gradually which would precipitate insoluble Ca carbonate as a byproduct of reaction with any Ca azide present, leaving NaN3 in solution. This would be detectable by evaporation or by precipitation of insoluble azide spot test by copper, lead or silver.

I wouldn't heat the mixture to reflux or even above room temperature. Leaving it stirring would during the hoped for reaction time seem right. Also it is of interest what may happen in an entirely aqueous reaction system.

I am thinking that more towards a neutral pH as would be true for the Hodgkinson reaction conditions may be required and that strongly basic conditions may be more favorable for the decompsoition of the nitrosamine than favoring the reaction of the nitrosamine with hydrazine. A neutral hydrazine salt as per Hodgkinson might be required as
opposed to free hydrazine.

[Edited on 18-11-2013 by Rosco Bodine]

Boffis - 18-11-2013 at 17:54

@ Rosco; Yes I was aware that a high pH tends to decompose the nitrosamine and I may try the reaction with just hydrazine and a nitrosamine and then add the alkali later as another alternative. The initial intermediate should be a triazine multi-triazene which is then decomposed by the alkali to an azide salt and the free base. In the case of 1,3,5 trinitroso triazine I think the free base would decompose to formaldehyde and ammonia; the former being decomposed under strongly alkaline conditions (hence the brown colour of the reaction mixture and small of ammonia). The reaction mixture is moist because my hydrazine hydrate is only 38% hydrazine or about 65% HZ hydrate. I had hoped that the reaction with hydrazine would be faster than the hydrolysis of the parent compound.

I wonder if you can reduce R-salt to a tri-N-amine the then diazotise the product and then decompose it with alkali to the corresponding azide, water and formaldehyde?

I'll try some other variation as well as the original Staudinger method with diphenylamine when I get chance. I'll also investigate the reaction products from my current experiments. I might also have another bash at a modified hodgkinson's method.

According to the excerpt above about the reaction of nitrous acid and hexamine, R-salt also gives a Liebermann's reaction. I'll investigate this claim and also whether other secondary nitrosamines, particularly diphenylnitrosamine, do likewise as this may help identify potential nitrosamines. If I can get my hands on some diethylamine I'll try this too and perhaps morpholine.

Pard - 9-1-2014 at 18:17

Is it possible to recrylise Lead Azide. most pdfs only mention the dextrion stabiltiy rouite. Tohougb I feel if youi clean it up nd then add it, You'd have something more storable

DubaiAmateurRocketry - 17-4-2014 at 01:16

When does a salt can be hydrated by its own cation again?
‘‘ Hydrazinium Azide Hydrazinate [N2H5]+ [N3]- (N2H4) Empirically N7H9 (Nearly 92% Nitrogen). The compound is less hygroscopic and less volatile than hydrazinium azide. Explosion of [N2H5][N3]N2H4 yielded dinitrogen (N2), ammonia (NH3) and dihydrogen (H2). I find this interesting for potential propellant additives.’’

Is it possible to synthesize for example hydroxylammonium azide hydroxylamine? Hydroxylammonium azide has been reported on some papers and synthesized by ion exchange with hydroxylammonium sulfate and potassium/barium azide and it have promising use in rocket propellants in theoretical calculations.

woelen - 20-4-2014 at 10:25

Just because I read a lot about azides last week, I was feeling it is time to do some actual experimenting and I tried something myself. I made a small amount of ammonium azide and I am surprised to see that this is not as energetic as I expected it to be. I also made copper(II) azide and that material is very energetic.

I have NaN3 as the only azide, so this is the starting material.

I prepared appr. 2 ml of a warm nearly saturated solution of NH4NO3 (appr. 50 C).
In a separate test tube I prepared appr. 1 ml of a hot saturated solution of NaN3.
Then I mixed these solutions. No precipitate is formed.
I allowed the solution to cool down to room temperature overnight. This produces some crystals of appr. 2 mm diameter.
Next, I put the solution in a fridge (at 5 C or so) and allowed it to cool down over several hours. After this, a lot more crystalline solid is present at the bottom.
I decanted the liquid from the crystals and put the crystals on a piece of coffee filter paper. Nearly all liquid is sucked from the crystals and they are quite dry already.
Next, I allowed the material to dry at room temperature. This works quite well. The material is not hygroscopic.
Now I have a small amount of NH4N3 sitting in a small glass vial.

I heated some of the material in a flame. When this is done, then the material ignites and simply disappears with a soft hissing sound. No explosion and only a pale orange flame. No smoke or visible vapor. When the material is not allowed any direct contact with the flame, then it melts and then suddenly it quickly disappears with a soft hissing sound.
As a control experiment I did the same with NaN3. When that is kept in a flame, it burns with a bright orange sparkling flame and it gives white smoke (most likely Na2O and/or NaOH).


I also made some Cu(N3)2 by adding a solution of NaN3 to a solution of CuSO4.5H2O. When this is done, then a very dark brown precipitate is made, which is flocculent, but quite compact. When some of this wet precipitate is taken out of the liquid and kept in a flame, then first most of the water evaporates and then suddenly there is a sharp and high pitched report of the exploding Cu(N3)2. This material is really powerful and also quite dangerous. Even when still wet it can explode.

---------------------------------

I now feel the need to have some KN3 as well. Using KN3 and perchlorate salts it is possible to make a whole bunch of azides which normally are hard to make or at low yield only. E.g. making NH4N3 is very simple with KN3 and NH4ClO4 because KClO4 is nearly insoluble in cold water. If I have KN3 then I can also try making azides of all kinds of metal complexes of which I now have the perchlorate salts (e.g. copper(II) ethylene diamine complex or nickel(II) ethylene diamine complex). Maybe I will try one of the synths for KN3 based on an organic nitrite and hydrazine hydrate in alkaline alcohol solution.

[Edited on 20-4-14 by woelen]

DubaiAmateurRocketry - 20-4-2014 at 10:29

Interesting! take a video!

You have some hydroxylammonium salts right? Please make a little bit of that, it might be much more energetic than ammonium azide. If you could try testing its sensitivity that'd great!

woelen - 22-4-2014 at 03:32

I have some hydroxylammonium salts (the chloride and sulfate), but with these it is very hard to obtain the azide. The reason for this is that the solubility of the azide is not much different than that of the chloride or sulfate and the sodium salts also do not differ very much in their solubility.

The reason why I could make NH4N3 easily is because
1) NH4N3 is much less soluble than NaN3, NH4NO3 and NaNO3 near 0 degrees Centigrade.
2) NH4N3 is not hygroscopic

Both advantages do not hold for the hydroxylammonium salt. Probably another solvent than water is needed, but there are not that many solvents which dissolve NaN3 and hydroxylammonium salts easily, while hydroxylammonium azide does not dissolve well.

PHILOU Zrealone - 23-4-2014 at 03:37

Ca(N3)2 and di-hydroxylamonium-sulfate should lead to CaSO4 precipitate and HONH3N3 in solution...
But hydroxylamine might not be sufficiently basic to react with the mild acidic HN3.... probably very sensitive to CO2 from air thus care!

DubaiAmateurRocketry - 24-4-2014 at 15:38

Quote: Originally posted by woelen  
I have some hydroxylammonium salts (the chloride and sulfate), but with these it is very hard to obtain the azide. The reason for this is that the solubility of the azide is not much different than that of the chloride or sulfate and the sodium salts also do not differ very much in their solubility.

The reason why I could make NH4N3 easily is because
1) NH4N3 is much less soluble than NaN3, NH4NO3 and NaNO3 near 0 degrees Centigrade.
2) NH4N3 is not hygroscopic

Both advantages do not hold for the hydroxylammonium salt. Probably another solvent than water is needed, but there are not that many solvents which dissolve NaN3 and hydroxylammonium salts easily, while hydroxylammonium azide does not dissolve well.


Ahh I see, I think this works.

Potassium Carbonate + Sodium Azide > Sodium carbonate + Potassium azide.

Potassium azide + Hydroxylammonium sulfate > Potassium sulfate + Hydroxylammonium azide.

If you can make calcium azide for PHILOU Zrealone 's method, that'd be great too.

The_Davster - 24-4-2014 at 16:34

Silver azide and hydroxylammonium chloride :D

Dornier 335A - 25-4-2014 at 00:24

That one might work. Silver azide is reported to be about ten times as soluble as silver chloride in water.
Barium azide is likely better than calcium azide. Both because its sulfate is almost completely insoluble in water and because barium azide is much less explosive than the calcium salt.

PHILOU Zrealone, Bis(hydroxylamino) azide is mentioned in Encyclopedia of Explosives and Related Items. It was prepared by evaporating a MeOH solution of hydroxylamine and hydrazoic acid. Its explosive properties were not investigated however.

Lead azide and PETN ina copper tube

aldofad - 4-7-2014 at 06:23

Hello world,
is it safe to load 500mg of lead azide and 500mg of PETN in a copper tube (8mm external diameter) in terms of contact between the energetics and copper? The device will be detonated in a couple of days after loading.

I know there are some energetics that do not react well with copper, but I can't remember which they are.

Cheers, thanks for help.
Aldo

PHILOU Zrealone - 4-7-2014 at 08:10

Cu is not compatible with azides because Cu azide is very sensitive.

To avoid any such risk...plate your inner copper tube with a lacker.
Or do as I do...I use drinking straw ...then fill it and press it sothat it fits perfectly the inner diameter of the copper pipe.
Also that way detonator is stored in the straw and made "effectively" contained by the copper pipe on site or little before use. Less risks of shrapnells in case of mishaps during storage.

markx - 4-7-2014 at 08:37


Quote:

Hello world,
is it safe to load 500mg of lead azide and 500mg of PETN in a copper tube (8mm external diameter) in terms of contact between the energetics and copper? The device will be detonated in a couple of days after loading.

I know there are some energetics that do not react well with copper, but I can't remember which they are.

Cheers, thanks for help.
Aldo


Safe....it most definately is not! Best not to use any metal containment of sizeable wall thickness...the risk of shrapnel is very serious. It can travel for respectable distances and carry some serious penetrating power. And please do not press the primary on top of the secondary in the metal tube with a metal loading pin. This is about the worst combination I can think of. It is the choice of industry, but it should not be the method for an amateur setting. I'm almost sure your press is not shielded either, right? Use the primary separately (in separate containment) and a small amount of loose secondary inbetween the two. Besides, 500mg of LA is serious overkill for PETN. Even 50mg would be more than enough to ensure reliable initiation.

[Edited on 4-7-2014 by markx]

hissingnoise - 4-7-2014 at 08:53

Quote:
Hello world, is it safe to load 500mg of lead azide and 500mg of PETN in a copper tube?

Anyone who needs to ask such a question should probably steer well clear of explosives . . . ?


aldofad - 4-7-2014 at 09:45

Quote: Originally posted by PHILOU Zrealone  
Cu is not compatible with azides because Cu azide is very sensitive.

Thanks for replying

Aldo

Airbag propellant question

NeonPulse - 30-4-2015 at 22:38

After a lot of sawing I was able to get into an old airbag gas generation unit. I have a question for somebody who has gotten the NaN3 seperated from the oxidiser contained in the pellets. I have looked at some of the threads here and other places and they all seem to say the pellets were black. These are green. It is from a 2003 model ford from the steering wheel unit. Could this be something else newer and not NaN3? There actually is not a lot of information out there on this subject and I've read what's available so any help would be appreciated. There was only 45g and other people have said that they got upto 90g What could the oxidiser be that is green? The Boron potassium nitrate was in a separate little compartment and easily seperated.the green substance seems insoluble in water so if there is azide it should be easy to reclaim via filtration and evaporation of the water, and provided there is nothing else water soluble I should get back reasonably pure NaN3.

image.jpg - 633kB

Hennig Brand - 6-5-2015 at 12:50

I have only seen black pellets so far, but then again I have only taken pellets from two different automobiles. The last bunch I had came from an old (1996) Honda Civic. I went to the patent literature from the years leading up to the year the car was made which gave me a good idea of approximately how much sodium azide was in the pellets. Dissolving a known mass of pellets in water, filtering and then using the solution to make lead azide with an excess of lead nitrate and weighing the final dry yield confirmed that the pellets contained ca. 65wt% sodium azide which was approximately what I had assumed after reading the patent literature of the time.

Haven't read about it for a while, but IIRC there were/are various things (oxidizers, fuels, etc) used in an attempt to get away from azides. You still may have azide though. I would try to make a small amount of lead azide, measure a yield and do a little qualitative/explosive testing of the product (if you get a product). Seems to me there was only about 50g or so in the steering wheel airbag in the 1996 Civic, but the passenger side airbag contained several times more.

markx - 7-5-2015 at 15:23

Clean and controlled primary of known quality is the key part of safety in any initiation attempt that relies upon it. It is not a sound approach trying to cut on the cost by using precursors of unknown composition in producing that part of the device. I would suggest to order/acquire a clean and controlled batch of precursors if possible, nevermind the cost. Unknown mixtures can have severe effects upon the stablity of the final product and cause a very nasty accident. Please be safe, friends!

NeonPulse - 8-5-2015 at 03:31

Not to worry but I won't be mixing any of these things with anything since they don't contain NaN3. It happens that I got one of the newer, safer gas generation units. Another SM member who just happens to be involved in airbag manufacturing filled me in on what he thinks these disks are as quoted form another thread:
the generant is usually a highly compressed pellet of a mixture of guanidine nitrate, 5-ATZ, and basic copper nitrate, along with some pentaerythritol for binding and carbon black for anti-static, and some other miscellaneous (and proprietary) bonding agents/burn rate modifiers.

I tried to delete my original post once I found out but couldn't work out how for some reason even though I've done so in the past.

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