Azides

A few days ago I went to the University library and got an entire 500 page book on inorganic azides. The book gives synthesis of all inorganic azides(metal and nommetal) and how to crystallize them, electronic structure, lattice dynamics, decomposition, etc..etc. Unfortunalty I do not have a scanner, otherwise I would upload it to the FTP. So if anyone wants info on any inorganic azide, I'll gladly retype the info that is wanted.
Something that I learned from this book that I did not know before was that there are 3 types of lead azide, with varying degrees of stability.
Keep in mind I only have 2 weeks with this book, but if there is enough demand for info I will renew it.

Azides of Antimony

Ammonium azide

University

The more I hear about that wonderful place the more I am determined to get into one; even if its just to read the books. So much information; its like treasure!

Knowlage is power and if I get to a University then I will rise up and be more powerful than you can imagine!

Well someday

[Edited on 10-5-2004 by Quantum]

When I went to that library there was rows and rows and rows of chem books. I am gonna live there in the summer.

azides :o

I wish you had a scanner Anything on Mercuric Azide? Also does it have anything on organic azido binders e.g. Glycidyl Azide?

Azides of mercury

Thanks dude!

Hydrazoic acid

That might be a convenient synthesis for both sodium nitrite and isobutyl alcohol wouldnt it, if you were to use nitrite "poppers"?

if you were to omit the H2SO4 that is.

[Edited on 19-5-2004 by Lestat]

Any info on halogen azides? my rather unscientific guess is that I imagine they would be rather unstable, given the usual behaviour of azides. Do halogen azides exist at all?

[Edited on 20-5-2004 by Lestat]

The info on lead azide has been uploaded to FTP2 under upload/rogue chemist/Lead azide. I would have put it in scipics but I dont know how.

Sodium azide files to come...

hey Froot,

Mine is the third edition. If that info is incorrect surely it would've been rectified by the 5th? Even now that it's been re-worded. Is there any way that this procedure for hydrazoic acid is possible?

[Edited on 1-7-2004 by froot]

I have also considered the possibility to find an old airbag and "extract" sodium azide from it. I once found a homepage with pictures and everything of an airbag being opened and the sodium azide removed. It contained quite a bit of NaN3, well above 100 grams IIRC. Of course this page is nowhere to be found anymore

The sodium azide was present as small pellets, which was dissolved in water to remove insoluble additives such as iron oxide and/or silicates which are added to react with the metallic sodium that is formed when the azide breaks down (into nitrogen gas and sodium metal vapour of course).

The extraction itself was quite straight-forward. I remember something about a screw behind the steering whell that was to be removed before the airbag was opened. This relaxed a spring inside the firing mechanism and made sure, that the airbag could not explode during the opening procedure. I doubt this mechanism can be found in all automobile brands though. I think it's most often an intirely electrical firing system.

The major problem I have encountered is: which cars/models have airbags that actually contain NaN3?. A lot of manufacturers have moved to safer alternatives that are not as toxic. I did some research about a year ago, and it seemed that there was a move towards nitrocellulose or compressed gas as the airbag propellant. If one wants to buy an old airbag it would be nice to know beforehand that it actually contains sodium azide and not a small canister of nitrogen, argon or something else!

Used airbags are also quite expensive as they are in high demand because people accidentally bump into things at low velocity, just enough to set off the airbag thus needing replacement. The spare-part dealers and scrap yards seem to know this, because prices are quite high in my experience. And usually you have to buy the entire steeringwhell and airbag unit just to get the NaN3, making it even more expensive
In the end it might me cheaper to make your own azide. It just takes time and decent lab equipment.

Although NaN3 is extremely toxic I wouldn't worry that much about it. Being a non-volatile solid I think you would have to be quite careless to cause any danger to yourself. Wearing vinyl gloves and maybe a dust mask should do it. Of course once you get the azide out of the airbag and start to play with it, one has to be extremely carefull. Certainly keep it out of direct sunlight and keep it dry and away from acids to avoid formation of HN3.

[Edited on 26-8-2004 by Nitramine]

ETHYL (R)-2-AZIDOPROPIONATE
[Propanoic acid, 2-azido-, ethyl ester, (R)-]


Submitted by Andrew S. Thompson, Frederick W. Hartner, Jr., and Edward J. J. Grabowski1.
Checked by Christopher L. Lynch and Stephen F. Martin.
1. Procedure
Ethyl (R)-2-azidopropionate. An oven-dried, 500-mL, three-necked flask is equipped with an overhead stirrer, nitrogen inlet, and an immersion thermometer (Note 1). The flask is charged with ethyl S-(−-lactate (19.2 mL, 0.169 mol) (Note 2), tetrahydrofuran (175 mL) (Note 3), and diphenylphosphoryl azide (40 mL, 0.185 mol) (Note 4). The mixture is cooled to 2°C in an ice-water bath. To the mixture is added 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) (24 mL, 0.157 mol) (Note 5) dropwise via syringe. (Caution: The DBU addition causes an exotherm. The reaction temperature is maintained below 5°C by carefully controlling the rate of addition. For this reaction the addition required 35 min). A thick white precipitate forms during the DBU charge. The reaction is stirred at 1°C for 1 hr, and then it is warmed to room temperature and stirred under nitrogen for 24 hr (Note 6). The resulting homogeneous reaction is diluted with methyl tert-butyl ether (MTBE, 170 mL), and water (100 mL) is added. After the water layer is removed, the organic phase is washed with water (100 mL) and 0.5 M citric acid monohydrate (100 mL). The organic layer is dried (Na2SO4) and concentrated under reduced pressure to ca. 40-50 g of a pale yellow oil (Note 7). The product is purified by simple distillation to afford 12.84 g (57%) of a clear, colorless oil, bp 83−88°C/50mm (Note 8), (Note 9) and (Note 10).
2. Notes
1. A Teflon-coated thermocouple of the J-type attached to an Omega model 650 digital thermometer can be substituted for the immersion thermometer.
2. Ethyl lactate was purchased from Aldrich Chemical Company, Inc., and used without further purification. The water content was 0.8 mg/mL by Karl Fisher titration (Metrohm model 684 KF coulometer).
3. Tetrahydrofuran was purchased from Fisher Scientific Company and dried over 4 Å molecular sieves for 18 hr prior to use. The water content was less than 0.05 mg/mL by Karl Fisher titration.
4. Diphenylphosphoryl azide was 98% as purchased from Aldrich Chemical Company, Inc., and the water content was less than 0.01 mg/mL by Karl Fisher titration.
5. DBU was 98% as purchased from Aldrich Chemical Company, Inc., and the water content was 0.5 mg/mL by Karl Fisher titration. The amount of DBU was calculated to be 0.93 equiv of the ethyl lactate charge by assuming a purity of 98% for DBU and 100% purity for ethyl lactate. Amounts of base over 1 equiv resulted in product epimerization.
6. The reaction typically requires 16-24 hr. The progress of the reaction was monitored by capillary GC after diluting a 0.1-mL sample with 1 mL of methyl tert-butyl ether. GC conditions: Hewlett-Packard 5890 series II GC using an Alltech Econo-cap column (30 M × 0.32 mm × 0.25 μM, catalog # 19646). [The submitters used an HP-5 column (25 M × 0.32 mm × 0.52 mm, HP part # 19091J-112)]. Start oven at 50°C, then increase to 250°C at 10°C per min. The reaction was considered complete after 90% conversion; starting material Rt 4.3 min, product Rt 7.0 min.
7. The vacuum was deliberately bled to maintain 120-130 mm to minimize product losses due to volatility.
8. The yield was based on the DBU charge. The product was contaminated with 4-8% of starting material that codistilled with the product. The following characterization data was obtained: ethyl (R)-(+)-2-azidopropionate: [α]D25 +14.8° (hexane, c 1.00); 1H NMR (250 MHz, CDCl3) δ: 1.28 (t, 3 H, J = 7.2), 1.43 (d, 3 H, J = 7.1), 3.89 (q, 1 H, J = 7.1), 4.21 (q, 2 H, J = 7.2); 13C NMR (75 MHz, CDCl3) δ: 14.1, 16.7, 57.3, 61.8, 170.9; IR (thin film) cm−1: 2120, 1743.
9. Optical purity can be quantitatively assayed by HPLC after reducing a sample to the amine with triphenylphosphine. A 50-mg sample was diluted with 10:1 THF:water (1 mL in a screw cap vial) and treated with triphenylphosphine (190 mg). Gas evolution begins within 5 min; once this subsides the reaction is sealed and placed in an oil bath at 50°C for 30 min. The mixture is diluted with HClO4 (pH 1.0, 1 mL) and washed with dichloromethane (2 × 1 mL). The acidic water phase contains the salt of the amine. A 200-μL sample was diluted to 1 mL and assayed by HPLC using a Crownpak CR(+) column (Diacel Chemical Industries): HPLC conditions; aqueous pH 1.0 HClO4, flow 0.5 mL/min, UV detection at 210 nm. The product had an enantiomeric excess of 96%, major enantiomer, Rt 3.4 min, and minor enantiomer, Rt 5.0 min.
10. The product from the distillation was analyzed by drop weight testing and differential scanning calorimetry (DSC). The drop weight test indicated that the product was not shock sensitive. By DSC, there was a 400 cal/g release of energy which initiated at 135°C. The pot residue showed a slow release of energy which was estimated to be ca. 100 cal/g and initiated at 150°C.
Waste Disposal Information
All toxic materials were disposed of in accordance with "Prudent Practices in the Laboratory"; National Academy Press; Washington, DC, 1995.
3. Discussion
Asymmetric introduction of azide to the α-position of a carbonyl has been achieved by several methods. These include amine to azide conversion by diazo transfer,2 chiral enolate azidation,3 4 and displacement of optically active trifluoromethanesulfonates,5 p-nitrobenzenesulfonates,6 or halides.7 8 Alkyl 2-azidopropionates have been prepared in optically active form by diazo transfer,2 p-nitrobenzenesulfonate displacement,6 and the Mitsunobu displacement using zinc azide.9 The method presented here is the simplest of the displacement methods since alcohol activation and displacement steps occur in the same operation. In cases where the α-hydroxy esters are available, this would be the simplest method to introduce azide.
In addition to α-hydroxy carbonyl compounds, the method can be generally applied for alcohol to azide displacements. This method has been successfully demonstrated on fourteen optically active alcohols.10 Mechanistically, this reaction proceeds in two stages. The first is alcohol activation via formation of the corresponding phosphate, and the second stage is the azide displacement step. The method is most useful for azide displacements of alcohols which tend to racemize using highly reactive groups for activation (e.g., sulfonate formation or Mitsunobu conditions11). When diphenylphosphoryl azide and DBU are used, the alcohol is only mildly activated for displacement as a phosphate. Use of the phosphate thus provides access to azide displacements of alcohols that are too sensitive using standard activation techniques. However, since the phosphate is only mildly activating, the alcohol undergoing displacement should be benzylic, allylic, or as in the present case, α to a carbonyl.
Certain classes of compounds are too reactive for the present method. Ethyl mandelate produced a racemic, protected phenyl glycine derivative. Benzylic alcohols with two methoxy groups (directly conjugating in the 2 and 4 positions) gave azide of 50% e.e.
Other classes of alcohols are unreactive. Ethyl 3-hydroxybutyrate (a β-hydroxy ester) went to the phosphate stage, but would not undergo azide displacement. In this example about 30% of the crotonate was formed because of β-elimination.

The webpage doesn't exist anymore. But I managed to find the homepage in my archives. Finally my tendency to save anything that seem exciting have paid off

I have just uploaded the page about extracting sodium azide from airbags here:

http://www.geocities.com/lenodk/NaN3.htm

3 types...

I thik he might be referring to something along these lines: Pb(N₃₂, PbOHN₃ (basic lead azide), and maybe a double salt or something with a different crystal structure?

edit: I'm not sure if there is a basic lead azide, but I know there's a basic lead picrate.

[Edited on 27-11-2004 by neutrino]

There are four polymorphic forms of lead azide. Despite the info being uploaded by me onto the FTP which I mentioned in a previous post, I will post it here because I have gotten a surprising number of requests about this information.

page 2

page 3

Page 4 is coming soon, one of my copies of it is not working so I have to find a working copy of it somewhere in my files.

OTC azide?

Copper (II) Azide

Darkflame mentioned copper azide above.

According to Brauer, when damp with H2O, copper II azide is fairly insensitive. However, when wet with ether (used for drying), or completely dry, it is relatively sensitive, explosion temperature is at 215 deg C.
More importantly, it is six times (!!) more potent than lead azide as an initiator, 450 times more potent as mercury fulminate!
(M. Straumanis u. A. Cirulis, Z. Anorg. Allgem. Chem. 251, 315 (1943).)

I can translate the prep if desired. Although it is not radically different to the Pb one.
It doesn't need dextrine to avoid big crystals though. Just simple metathesis between copper nitrate and sodium azide, and additional washing with HN3 (), and immediate washing with ethanol and then ether.

[Edited on 13-4-2005 by chemoleo]

Oh dear...

I just realized I never posted info on copper azide for darkflame. I apologise.

You might find these of interest as well Chemoleo.

Overall I like the idea of copper azide, especially because I dislike explosives that release finely divided poisonous metal into the air.

page 2

page 3

Preperation of Azides

Translation

THANK YOU

The Hodgkinson Azide Patents

GB129152

probably as easy as it gets

interesting method has potential ....

A source of Barium Azide

I wasn't sticking around to gork at it

The PET bottle would be a good idea to try force an explosion. Add the reagents and balloon on the bottle. The pressure may explode the HN3, if not shoot it etc. thus getting a measure of safety.

I dont know the compatibility of HN3, though I did use a long PVC tube to carry the gas to the Pb acetate solution.

EDIT: I added 5g 50% H2O2 into 180g H2SO4, 60g H2O, 2.5g N2H4.H2SO4. This was a couple days ago, result of adding the peroxide to the warm acid solution was immediate bubbling of the solution. I just let it bubble off into the atmosphere at this time. So no, I never directly substituted H2O2 on the method I posted above, but I would think it would work in the same way. Though it may be undesirably quicker since the persulphate hydrazine sulphate isn't all in solution when h2so4 was added..

[Edited on 20-4-2005 by Axt]

transparent det cord

Quote:

Originally posted by Rosco Bodine transparent det cord

Agreed that hydrazine sulfate is the greatest difficulty about the entire process . But in my absolutely unbiased opinion , Mr. A has already solved that difficulty with the urea - pool chlorinator method which uses HCl for the byproduct neutralization followed by the H2SO4 addition to obtain the hydrazine sulfate as very pure gritty crystals in good yield .

Also agreed that the freebasing of the hydrazine into alcohol , followed by nitrosation of the basified alcohol solution is the best high yield method known so far , and that no destructive oxidation scheme for hydrazine can compare in the amount of azide ultimately produced from
a given weight of hydrazine sulfate .

However , even though the oxidation of hydrazine only produces about a third as much azide from the same amount of hydrazine sulfate , it does provide an
alternative process at much lowered efficiency , but it is a " no nitrite - no nitric acid either " alternative which does
cause it to have interest for that reason alone . Additionally there is the chance
that the yields may be possible to be improved , even though the yields will never approach the nitrosation reaction yields , because of nitrogen losses as
the byproduct ammonia .

Hehe, Axt and his (in?)famous one pot syntheses!
If you get that to work, you get the MS award of the year
Oxidation of urea to hydrazine, then onwards to HN3, then feeding the steam straight into Pb(Ac)2 --> lead azide....
No messing about there! and def. cheap/easy reagents


On the note of the Raschig process - yah, it's easy, but still a pain in the butt. All this endless boiling, usage of large amounts of ammonia/NaOCl, to get 5 g of hyd. sulphate

Anyway, I believe garage chemist tried the method from Mr. A., so maybe have a word w. him.

Actually it could be run as one pot process , just make the hydrazine sulfate
first and decant the salt water from the crystals , add your persulfate solution to
the still damp hydrazine sulfate , and then drip in the sulfuric acid .

Out comes pure Australian HN3

Tie me kangaroo down boys ,

tie me kangaroo down .

http://www.southcom.com.au/~seymour/kaufman/ozus/Slang.htm

[Edited on 21-4-2005 by Rosco Bodine]

Hydrazine preparation

Hmmm with this mention of hydrazine in an azide thread ..... I am not sure where to reply

Better watch out , we might make some azide after all following that oblique and
disconnected logic Seriously , hydrazine and azide are like flip sides of the same coin with regards to any labscale methods for azides . So the
two seemingly divergent topics will remain closely related and indeed interrelated , since the azides are daughter compounds of hydrazine .
Even the tetrazoles are family relations .
It always comes back to hydrazine as
the key precursor in convenient syntheses for these materials .

I think it was all the discussion earlier about the *preliminary* synthesis of hydrazine sulfate , which was " off topic " with regards to azides , yet several on topic posts related to azides from hydrazine were moved over to the hydrazine thread when those half dozen posts may still actually belong here .

Anyway , with regards to the freebasing of
hydrazine and then its subsequent basification further with added NaOH :
You need to limit the stoichiometric excess of NaOH used in the initial freebasing to a few percent , maybe 10%
at most NaOH in excess of theory , and after doing your multiple extractions with
fresh portions of alcohol , then add your
adjusted equivalent molar amount of NaOH to the combined extracts , so that your combined total of NaOH is only about 5% maximum in excess on a molar basis , above the theoretical requirement for the nitrosation reaction . The residual water
content in the NaOH will make the actual
excesses slightly lower , so these are good working proportions . When you use too great an excess of NaOH in the freebasing , then the excess NaOH is going to be hydrophilic and complicate the extraction . And if there is too much excess of NaOH in the extract during the nitrosation , then it will preferentially hydrolyse the organic nitrite to form the alkali nitrite which will precipitate along with the sodium azide formed later as
a contaminated and reduced yield second product .

For example , if you were freebasing a mole of HS , use a total of 88 grams NaOH for the freebasing . Then add 34 grams of NaOH to the combined extracts prior to the nitrosation . Do not dissolve your 34 grams of NaOH in a separate portion of alcohol , but simply add the solid NaOH in portions to the chilled extracts until all is in solution . On standing overnight in the cold , a small amount of undissolved precipitate , carbonate impurity from the NaOH and sodium sulfate carried over from the extractions will settle out and the clear solution may be decanted leaving most of the small precipitate adhering to the bottom
of the flask . From the basified hydrazine in alcohol the NaN3 should separate in very pure condition . The drier the extract , the less will be the tendency for the azide to precipitate as an adherent layer which sticks to the glass .

[Edited on 6-5-2005 by Rosco Bodine]