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Author: Subject: Sodium Azide
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[*] posted on 19-10-2002 at 21:40
Sodium Azide


Does anyone know how to synthesize this compound. Ive been doing sume searching but found nothing.
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[*] posted on 19-10-2002 at 22:12


Yes, it can be made by the reaction of hydrazine hydrate with isopropyl/ethyl nitrite (not nitrate!) and sodium hydroxide. However, if you want it for making lead or silver azide, they can be made directly from hydrazine hydrate, and lead/silver nitrite.
hydrazine hydrate can be made be the reaction of sodium hypochlorite (bleach) with ammonia, in the presence of gelatine.
Followed by forming the insoluble sulfate salt from the addition of sulphuric acid. Then, to form hydrazine hydrate, react the hydrazine sulfate with sodium hydroxide. However that will leave a reasonably dilute hydrazine solution due to the low solubility of hydrazine sulfate in water. It may be better to first form the nitrate salt, and react that with sodium hydroxide.
Be very careful about hydrazine though, it is a carcinogen and very poisenous, but with good technique and equipment this can be done safely.
There is another route of making sodium azide i have heard of involving semicarbazide and sodium nitrite, however i have no specifics on this procedure. It would be a good alternative to hydrazine, as it can be made from urea, ammonia, and sodium hypochlorite, with very good yields, whereas the yeilds for making hydrazine are quite poor. Semicarbazide is also alot safer than hydrazine. If anyone has any info on preparing sodium azide from semicarbazide please let me know?
If you want any more info on the hydrazine procedure id be happy to let you know.
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[*] posted on 20-10-2002 at 03:42


I'd recommend using urea instead of ammonia for making hydrazine. It means you don't get a house full of ammonia, especially if you can't get very good ventillation!
Check out the Hive for a synth from urea. I tried it, using fertiliser grade urea, <5% NaOCl household bleach, gelatine, drain-cleaner NaOH granules and tap water. The yield was just over 15%, while this is not very good it is a very cheap method. The yield is improved greatly by using Ca(OCl)2 instead of NaOCl, because of the Ca(OH)2 present. Adding Ca(OH)2 to a synthesis using NaOCl also increases efficiency. Using distilled water helps by reducing the ammount of transition metal ions, and using pure urea would also be a great help. The text I followed reported a 75% yield based on urea!
To make azides, it's probably best to first make a solution of hydrazine nitrate, by mixing strong solutions of hydrazine sulphate and calcium nitrate, and then filtering off the CaSO4 ppte. Otherwise you might end up with a lot of ppted PbSO4/Ag2SO4 in your product, depending on what you are trying to make.
I wanted to make semicarbazide for NTO and azides, but never got a very good yield from any of the methods I tried. For making azides, it's MUCH easier to use hydrazine (and semicarbazide is not very much less toxic than hydrazine anyway). It would be nice to be able to make NTO, but because of the trouble of having to make the semicarbazide it's better to use another HE.
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[*] posted on 20-10-2002 at 04:54


the gelatine is there to complex bind metall ions ? then it would be perfectly fine to use EDTA instead , which also binds very strongly to metall ions. ?

/rickard
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[*] posted on 20-10-2002 at 05:36


Yes, apparently the gelatine helps to bind up metal ions, and I think it helps to slow the reaction between hydrazine and hypochlorite ions, but I think it's mainly used to get rid of transition metal ions.
I've heard someone talking about using EDTA, but I'm afraid I can't remember if they actually tried it and had success, or if they were just wondering if it would work.
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[*] posted on 20-10-2002 at 08:17


I don't think gelatine is necessary for preparing hydrazine from urea and calcium hypochlorite. These are the reactions that take place when ammonia is reacted with sodium hypochlorite:

NH3 + NaOCl ----> NaOH + NH2Cl
NH3 + NH2Cl + NaOH ----> N2H4 + NaCl + H2O

And here is the parasitic reaction that is catalyzed by the presence of heavy metal ions:

2NH2Cl + N2H4 ----> 2NH4Cl + N2

Obviously the ammonium chloride is going to react with sodium hypochlorite to liberate chlorine gas.




I weep at the sight of flaming acetic anhydride.
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[*] posted on 20-10-2002 at 11:25


Quote:
Obviously the ammonium chloride is going to react with sodium hypochlorite to liberate chlorine gas.


In that case, I'd be a bit wary; ammonium salts plus Cl2 will produce nitrogen trichloride. I've experienced a hideous scent and some violent popping before when mixing ammonium salts and calcium hypochlorite.
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[*] posted on 20-10-2002 at 12:17


NH2Cl isnt the most stable compound in the neighbourhood either...

not to mentioning the fact that ClO- forms ClO3- by a disproportion reaction and this is also a potential dangerous ion in combination with NH4+.
But as long as you are working with dilute mixtures of low concentrations you should be fine.

/rickard
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[*] posted on 20-10-2002 at 16:41
Why bother


If you can get to a junkyard then you don't have to bother making NaN3. Airbags have upto 100g of NaN3 in tablet form with added Fe2O3 and SiO2. These can be removed right before use by filteration. Actually some airbags did come out with RDX/AN mix, but I think it was discontinued due to the hygroscopic nature of AN. The NaN3 is encased in an Al case with gas vents to inflate the airbag. I don't think the Al case can be unscrewed easily ..... it can also be sawed but it has to be kept cool by some sort of a solvent.
Happy Aziding. :P
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[*] posted on 21-10-2002 at 00:18


Nick F, i haven't tried the route for making semicarbazide myself, but another member (who seems to be very intelligent, and i would certainly trust, his name is microtek) on the E & W forum has tried it and reported very good yields.
The procedure is something like this:
50ml of 15% sodium hypochlorite (5% could also be used if the amount were tripled) is added to a solution of 9g of urea in water (the sodium hypochlorite must be added to the urea, not the other way round or hydrazine will be formed) to make monochlorourea; sodium salt.
50ml of 20% ammonia with 2g of zinc chloride dissolved in it (there are other catalysts that can be used, but this is probably the easiest) is added to the solution of monochlorourea, and is heated with some gladwrap over the top (because he didn't have a reflux condenser i think). I can't remember how long he heated it for, but then he added another 50ml of ammonia, and heated till dryness, he then added hydrochloric acid to the impure semicarbazide to make semicarbazide hydrochloride. The semi hydrochloride is reasonably insoluble in 30% HCl so it can be filtered out leaving most impurities behind.
To purify it he made a saturated solution of it in water, and bubbled HCl through it to precipitate the semi HCl. He reported a good yield. For a better description look under the NTO topic in High explosives on the E & W forum.
Yes i've heard that the yield using calcium hypochlorite is greatly improved, but i still think that its safer and easier using semicarbazide, because its a non-volatile solid, and its pretty difficult to tell the concentration of your hydrazine, hopefully soon (next wekend hopefully), i will try preparing both semicarbazide and hydrazine, and compare yields to cost. Ans oon i'll try making azides from both.

Nick, do you have any specifics on making azides from semicarbazide opposed to hydrazine? Does it still require a nitrite ester?

I'll check the hydrazine synthesis from urea.

And yes EDTA, can be used in place of gelatine, also gelatine, and a few others can be used, but gleatine gives far better yields.
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[*] posted on 21-10-2002 at 04:29


I know about the NTO topic on the E&W, I started it ;)
It did sound like he got a good yield, although urea*HCl would also ppte if unreacted urea was present, so determining the purity of the product may be difficult.
I found a lot of methods for making semicarbazide*HCl, some of which I found patents for and posted them in "Links and Literature" on the E&W, and the one with urea is definitely the nicest. Actually, I suppose that method is even nicer if you have something like .880 ammonia solution and a pressure vessel, but since I don't have either I'd have to bubble through a massive excess of ammonia gas, either directly into the solution or into water to make an ammonia solution that could be added, and I hate working with lots of ammonia gas!
If using hydrazine, it can be stored as the sulphate or hydrochloride, and made into a solution of precisely known concentration by adding aq. NaOH. Sulphate and chloride ions might be a problem in some reactions (such as making silver or lead azides), in which case the nitrate is prepared from the sulphate using Ca(NO3)2.
I don't have any specifics for making azides from semicarbazide, I think I heard that it was possible on the Org Syn website, but they gave no details. I'm not sure if it needs a nitrite ester or not... if it could be done with NaNO2 in neutral/basic solution then it would be very good...
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[*] posted on 21-10-2002 at 05:17
I haven't tried this but.....


here it is anyway.
Manganese Heptoxide
Author: Exxperts
Materials: potassium permanganate (KMnO4), sulfuric acid 92-96%
Procedure: Place 5g powdered potassium permanganate in a small beaker. To this add 5ml concentrated sulfuric acid. Gently swirl the mixture to blend the components. If unreacted permanganate remains in the bottom, add more H2SO4. Do not filter! A dark green oily liquid will have formed. This is manganese(VII) heptoxide (Mn2O7), a powerful oxidizer. It ignites almost every organic compound. Alternatively, the process can be reversed: Mix KMnO4 with an organic compound and add a few drops of conc. sulfuric acid to ignite. Some experiments to do with it: Wear a face shield and leather gloves. Twist a wad of cotton around a wooden splint, immerse this in the liquid and take it out immediately. The cotton will start burning in 1-5 seconds. Place any organic compound (sugar, flour, starch, pieces of wood, hay, paper, styrofoam...) on a fireproof surface, by addition of a few drops of Mn2O7 these will catch on fire. Flammable liquids (ethanol, gas, acetone, toluene, paint thinner...) can be lit in a similar fashion.
WARNING: Pour the flammables out in a thin layer in an open area! Never mix Mn2O7 with a liquid like acetone in a test tube or similar vessel. The mixture may be ejected violently or even explode! Never mix Mn2O7 with powdered metals, the mix will explode and unreacted Mn2O7 along with excess acid will spray in all directions!

Properties: Dark green to greenish black oily liquid. Soluble in water and sulfuric acid. Decomposes at 55°C, may explode at a slightly higher temperature, or on prolonged storage.

Barium Peroxide

Preparation: Prepare a solution of 47g of barium chloride dihydrate in 250ml water. To this solution add 250ml 30% H2O2. Add 200ml 24% aqueous ammonia solution with stirring. Let the mixture stand until no more precipitate forms. Decant the clear portion, and replace the liquid with fresh water. Repeat the decanting 2-3 times. Filter on a Buchner funnel and wash with water. Dry in a porcelain cup at 50-70°C, occasionally spreading the powder with a spatula. After the product turns into a crumbly mass, increase the temperature to 75-80°C. Store the completely dried product in a tightly sealed bottle. Yield: 55-60g of the octahydrate. The product can be further dried to the hemihydrate at 130°C. The completely anhydrous peroxide can be obtained above 200°C, but a partial loss of oxygen will occur.
Carbamide Peroxide
Author: Lagen
Using a mortar and pestle, crush 20g urea into a powder. Place this in a shallow pyrex dish and add, with stirring, 35ml of a 30% hydrogen peroxide solution. The resulting mixture should have a dough consistency. Stir in 1.5g of powdered gelatine. Let the mixture stand for 5 hours, it will solidify, forming the carbamide peroxide. Uses: In smoke compositions. Mixtures with sodium dithionite are impact sensitive.
Magnetite

Preparation: Dissolve 25 g of iron(II) sulfate heptahydrate (green vitriol) and 25 g of iron(III) (ferric) sulfate nonahydrate in 500 ml water. Add this solution to 1 liter of boiling 5% KOH solution. Filter out the precipitate, wash with hot water and remove excess moisture on a Buchner funnel. Dry in a hydrogen atmosphere over CaCl2 or conc. H2SO4. This way the dihydrate is obtained. Calcine at 300-400°C in a nitrogen atmosphere to obtain the anhydrous product.
Properties: Fe3O4, magnetite can be used instead of iron(III) oxide in thermite mixtures, to get a higher temperature. An alternative process exists, starting by precipitating Fe(OH)2 from a soluble Fe(II) salt and calcining this at 800°C, but I don't have the details.

Pyrophoric Iron
Author: Maty
Materials: oxalic acid dihydrate 20g, iron sulfate heptahydrate 44g, distilled water
Equipment: a larger heat resistant test tube, 250ml and 500ml beaker, glass rod, heat source
Procedure: Place 20g of oxalic acid and 200ml distilled water into the 500ml beaker. Distilled water is necessary, tapwater contains cations that combine with the oxalic acid to form unsoluble precipitates. Boil the solution with stirring until the oxalic acid dissolves. In another 250ml beaker dissolve 44g of iron sulfate in 200ml boiling water. Pour the iron sulfate solution into the oxalic acid solution, with stirring. A fine yellow precipitate of iron oxalate should form. Filter out the precipitate and thoroughly wash with water on the filter (sulfuric acid will have formed in the precipitate and needs to be removed). Dry the powder in a warm place, avoid too much heat. Crush the dried powder to flour consistency. Place the powder in the heat resistant tube and gently heat the tube, continue the heating until all the powder turns black. If necessary, carefully stir the powder. Warning: The black powder that has formed is pyrophoric, which means it will spontaneously ignite in air, if hot. It gives off nice yellow sparks.
Properties: You can use this powder in pyrotechny to create yellow sparks, in self-igniting mixes as well as in the production of iron sulfide. A similar procedure can be used to produce powdered copper (colours flame green).

Pyrophoric Lead
Author: Oktogen
Prepare a solution of 2g lead acetate in water and acidify it with a few drops of acetic acid. To this solution add a stoichiometric amount of tartaric acid or primary potassium tartrate (in the form of a 5% solution) in several portions, with stirring. Filter the white precipitate at reduced pressure and wash on the filter with water. Dry at 110°C. Spread out the dry material in the lower section of a specially modified test tube.
(Hold an ordinary test tube with a metal clamp and heat in a burner flame about 3cm below its mouth. Keep rotating the tube along its axis. After the glass had softened, stretch out the tube so that the neck shrinks to about 3mm diameter. After cooling make a dent in the narrow section with a file and break it apart.)

Fix the tube in a stand in a tilted position. Heat the tube evenly. After the decomposition of the lead tartrate had ceased and all the water vapour and other decomposition products had escaped, take away the tube and pour out the pyrophoric lead onto a fireproof surface. Alternatively, you could carefully fuse the tapered neck of the tube to preserve the material for later use.

Sulfur

Preparation: Dissolve 25 g of sodium thiosulfate (photographic hypo) in 83 ml of 25% acetic acid. Heat the mixture gently until the evolution of gas stops. Let the mixture stand for a day. Carefully decant the liquid portion, wash the precipitate with water to a neutral reaction. Filter on a Buchner funnel, moisten the product with acetone and dry at room temperature. Yield: 3 g of colloidal sulfur.
Potassium Nitrosocarbaminate
Author: Lagen
Procedure: Place 38 ml of methanol in a 100 ml beaker. Add 10 g of dry potassium hydroxide, in several small portions and with stirring. Wait for each portion to dissolve, then let the solution cool down. Pour off some of the resulting solution in another container, keep approx. 30 ml of solution in the beaker. Place the beaker in a salted ice bath. In another container liquefy 1g of nitrosourethane with a few drops of methanol and add 4 ml distilled water. Add the solution in one portion into the potassium hydroxide solution and let it react for 10 minutes. If nothing precipitates, add 5 ml of the spare potassium hydroxide solution and wait for another 10 minutes, then add the remainder of the KOH solution. Let the mixture stand for one hour, keep replacing the ice bath if it melts. Quickly vacuum filter the precipitate, wash several times with absolute alcohol and place immediately in a desiccator. Try to avoid unnecessary contact of the product with moist air. Yield: approx. 1 g of a pale yellow powder.
Properties: Potassium nitrosocarbaminate - NONKCOOK. Very sensitive. Detonates violently, even in small amounts, on contact with water or sulfuric acid. May detonate at slightly elevated temperatures (below 100°C). Decomposes in the presence of moisture. It can be temporarily rendered nonexplosive by the addition of ether followed by addition of alcohol. When treated in this way it can be decomposed safely by water or H2SO4.

Triaminotrinitrobenzene (TATB)
Author: Exxperts
Precursors: The 1,3,5-trichloro-benzene necessary for this synthesis may be prepared by direct chlorination of benzene using iron filings as catalyst, or more conveniently, by halogenation of aniline, removing the amino group by diazotization and boiling in ethanol.
Nitration: Into a suitable flask immersed in an oil bath place 220ml conc. H2SO4 and add 51g NaNO3. Heat the mixture to 100°C with constant stirring and hold the temperature for 20 mins. This will cause the decomposition of the nitrate by H2SO4 to form free and almost anhydrous HNO3. The H2SO4/HNO3 nitrating mix also helps to greatly reduce the destructive oxidation processes occuring in the aromatic ring during high temperature nitration.

Following that add 20g of 1,3,5-trichloro-benzene into the nitrating mix and increase the temperature to 145-155°C. A high temperature is necessary in order to completely nitrate the TCB. The temp. must be maintained close to 150°C for 4 hours, after that the mixture is allowed to cool to room temperature and then poured into a container with 800g of crushed ice. TCTNB will fall out in the form of heavy yellow crystals. The crystals are filtered out and washed with water to a pH of 6-7. Dry thoroughly at 40-60°C.

Amination: 20g of the dry TCTNB is dissolved in 150ml toluene at 90°C. Gaseous ammonia is bubbled through the solution over a period of 2 hours (the temperature is maintained at 90°C). The amount of ammonia used should be 150% of the theoretical. After the amination is completed, the redundant toluene is distilled off (either on its own or with the addition of a small amount of water to form an azeotrope). The resulting TATB (beautiful yellow crystals) is washed with 60°C water several times and dried. Yield: 13.5g TATB (95% theory).

Ethyl Nitrate without distillation
Author: Fly
Procedure: Prepare a nitrating mix using 260 ml 65% HNO3 and 300 ml 96% H2SO4. Slowly add the H2SO4 to the HNO3 with cooling and constant stirring. Let the nitrating mix cool down to 0°C in a refrigerator. In another container place 160 ml of pure ethyl alcohol and slowly add 16 ml 96% H2SO4 with cooling and stirring. Let this mix cool down to 0°C as well. Prepare a salted ice bath and place a 1L or larger beaker in it. Pour the cold nitrating mix into the beaker, place a thermometer in it and begin the addition of the cold ethanol mix. Keep stirring the mixture, adjust the rate of addition so that the temperature stays around 5°C, do not allow the temperature to rise above 10°C. When the addition is complete, continue stirring the mixture for another 5 mins. Transfer the mixture into a separatory funnel and let it stand for 15 mins. The crude ethyl nitrate should separate out, drain the acid portion. The separation should not be carried out for more than 15 mins., after that the product might start oxidizing. The crude ethyl nitrate is washed by 300 ml of cold water (shake the mixture thoroughly in a plastic bottle). Repeat the separation and wash the product again with 300 ml water, then add a small amount of NH3 solution to the mixture and shake it again. Repeat the NH3 addition until the solution is pH neutral. Repeat the separation and washing steps, check that the product is clear and colorless. Now the product can be finally separated, dried over CaCl2 and filtered. The product obtained in this way should not be stored.
Ethylenediamine dinitrate (EDDN)
Author: Locker
Procedure: Into a 750 ml beaker immersed in a salted ice bath (ice+NaCl or ice+NH4NO3) place 40 ml distilled water and slowly add 100 ml ethylenediamine. As the ethylenediamine used here is a strong base, this addition will produce a lot of heat, and the temperature may rise to approx. 70°C. Add a little water to the ice bath and let the solution cool down below 0°C. In the meantime, into another 500 ml beaker immersed in water and cracked ice place 200 ml of 65% HNO3 and allow it to cool.
When the ethylenediamine solution has cooled down, begin the slow addition of the nitric acid, with continuous stirring. Do not allow the temperature to rise above 25°C. Although an explosion is not likely, when large amounts of the two solutions come into contact, the reaction mixture could start boiling and possibly be ejected from the container.

At first the reaction will be rather violent with each small addition, but will calm down later. As soon as there are no obvious symptoms of a reaction with the addition of acid, start monitoring the pH of the mixture. Stop the additions when the pH is in the range of 5-5.5. If the pH is higher, the product will have a tendency to decompose, if it is too low, the product will be difficult to dry and may decompose as well. Stir the mixture for a few minutes. If any product crystallizes change the ice bath for a heated water bath and wait for the product to redissolve.

Pour the contents of the beaker into a shallow aluminum or enameled tray and place it in an oven, maintain the temperature at 60-70°C. The evaporation should take 6-7 hours. The product will resemble ammonium nitrate crystals in appearance. To speed up the evaporation, stir the solution ocassionally. Collect the dried product and store it in an airtight bottle (f.ex. a soda PET bottle), it is hygroscopic. Yield: 260-270g

Acetone Semicarbazone
Author: Lagen
Precursors: Zinc can be crushed to a powder at a temperature above 210°C. Battery cathodes, cleaned from MnO2, are a good improvised source. Synthesis of nitrourea is well known and can be found at many other web sites.
Place 455 ml of 31% hydrochloric acid in a suitable container and let it cool down to below 0°C in a refrigerator. Stir in 45 g of powdered nitrourea and return the solution to the refrigerator. Place 150g of zinc powder in a 800 ml beaker and add 80ml water. Place the beaker in a salted ice bath and cool the mixture to 0°C. Insert a magnetic or mechanical stirrer and start stirring the mixture. Begin the addition of the nitrourea solution; keep the additions small, especially at the beginning. The temperature should be kept below 0°C; replace the ice bath if necessary. Turn off the stirrer, let the mixture sediment and decant the liquid portion through a filter. Add 40g anhydrous sodium acetate to the filtrate and let it dissolve. Saturate the solution with sodium chloride (approx. 140g), then add 26 ml acetone. Allow the mixture to react in an ice bath for several hours. A precipitate of acetone semicarbazone addition compound with zinc chloride will form. Filter out the precipitate and wash with cold saturated sodium chloride solution, then with ice cold water. Dry the powder in an oven; the temperature should not exceed 100°C.

Place 30 g of the dried powder in a 250 ml beaker and add 70 ml of a 24% ammonia solution. Allow to react for 30 minutes, then filter out the product. Wash with a small amount of ice cold water and dry in an oven at a low temperature. Yield: 20-27g, using all of the addition product from the first stage.

Notes and Discussion: Acetone semicarbazone may be converted to semicarbazide nitrate or sulfate (see on this page) with the concentrated acids. These salts can be used for preparation of triazolone, a precursor to nitrotriazolone (NTO). Compared to the conventional synthesis using semicarbazide hydrochloride, this offers the advantage of low chloride content in the triazolone, which is beneficial for nitrotriazolone synthesis. Even more conveniently, the acetone semicarbazone can be used directly in the preparation of triazolone. See US patents # 4,927,940 and 4,999,434 for more info.

Zinc can be recycled from the waste filtrate produced in the second step. Other ways of preparing semicarbazide or its precursors exist (f.ex. reduction of nitrourea with molecular hydrogen at superatmospheric pressures in the presence of a rhodium catalyst), but this one is the most convenient for the home chemist. It does not use the toxic and carcinogenic hydrazine nor compounds thereof, and requires only very simple equipment.

Semicarbazide Sulfate
Author: Lagen
Preparation: Add 10 g acetone semicarbazone in 10 ml of 96% sulfuric acid, heat the solution gently until the powder dissolves. Allow the solution to cool and pour into 100 ml of absolute ethanol. Filter out the precipitate and crystallize from warm water.
Properties: Semicarbazide sulfate - NH2CONHNH2.H2SO4, very soluble in water, insoluble in ethanol. Large prisms, m.p. 144°C. Decomposes above 120°C, yielding mostly hydrazodicarbonamide and hydrazine sulfate. Useful for preparing triazolone, see also acetone semicarbazone.
Hope this helps :P
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[*] posted on 22-10-2002 at 10:00
Damn ......


I can't edit ..... I only wanted to post the semicarbazide prep and not all that stuff. I made such a big post ......
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[*] posted on 27-10-2002 at 06:11
substitution


Someone knows the elektron-scheme of a
X-N3 substitution with a [Cl/Br/F]-benzene ?




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[*] posted on 24-12-2002 at 21:27
Ahhhhhhhh


ok i had found this site that tells you how to get the sodium azide out of the airbag container. http://www.geocities.com/eawfuk/sodium_azide_from_airbag.htm

But a few things I dont get is the purification. Sodium azide reacts with many liquids. Silicon dioxide and iron oxide are insoluable in water so you can just dissolve the sodium azide in distilled water and filter then evaperate the water.But will sodium azide react with water and liberate HN3? this gas is extreamly toxic and presents an explosion hazard.




TNT
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[*] posted on 25-12-2002 at 04:18


sodum azide will not react with pure water, since pKa is 4,72, much stronger than water, thus N3- will not absorb H+ from water.

However , the N3- ion is of course very toxic, as most here probably already know. One of the reasons one of the first things they do at the scarp yard is to remove the airbag charge.

/rickard
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[*] posted on 30-1-2003 at 16:09


has some one done it NH4NO3+200C=2H2O+N2O anhydrous something"""+Na3N=NaN3+...
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[*] posted on 22-11-2004 at 08:18


I've 'successfully' produced NaN3 using the method whereby methyl nitrite is bubbled through a mixture of methanolic NaOH and hydrazine hydrate but the product seems to be rather heavily contaminated with unreacted NaOH.

In order to remove the NaOH I figured that I could try saturating methanol with the raw product and adding hydrazine prepared from hydrazine sulfate and minimal NaOH and bubbling methyl nitrite through the solution again. The idea being to try and react all the NaOH before extracting the NaN3. The only problem being that it may still be contaminated with NaSO4 and hydrazine sulfate.

Could there be another way to remove the NaOH from the NaN3 in the product?




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S.C. Wack
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[*] posted on 22-11-2004 at 09:06


The usual way is by precipitation of a solution with alcohol.
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[*] posted on 22-11-2004 at 10:12


A practical method for pure crystalline sodium azide has been carefully worked out and tested by me and I have posted the general description both here and at E&W , but not yet given a detailed step by step . The method requires proper lab glass and teflon apparatus and a magnetic stirrer , and generally anyone having those things could duplicate
the process from my general description , so I never described it further . The method involves freebasing hydrazine hydrate from solid hydrazine sulfate with solid sodium hydroxide using a minimal amount of water just sufficient to initiate the reaction between the solids , the byproduct water from the freebasing being sufficient to result
in a just stirrable warm slurry of porridge like consistency , which consists of solid sodium sulfate and hydrazine hydrate in water . Alternate portions of the solids are added to the stirred reaction mixture along with just enough water added by drops to prevent the mixture from setting up solid . To perform this freebasing , I use a 1 liter erlenmeyer having a ground joint and glass stopper greased with silicone , and a three inch octagon stirbar , set upon a stirrer hotplate on low heat . Initially I put about half the solid hydrazine sulfate into the flask , dampened with a few ml of distilled water . The solid fine prilled NaOH
in an amount slightly over the amount of theory required for freebasing
all of the hydrazine in the total batch is preweighed and put into a plastic bottle with a dispenser tip having a snap cap , like a glue dispenser bottle where you can cut off the tip to size the delivery opening . This allows for the addition in portions of solid NaOH , and stoppering the flask and capping the plastic bottle of NaOH between additions to exclude moisture and air , which will otherwise complicate matters during the manipulations of these materials . When the first portion of hydrazine sulfate has become a thin slurry from additions of NaOH , the rest of the hydrazine sulfate is added and the additions of remaining NaOH continued , adding any minimal amount of water needed , by the eyedropperful , using only sufficient water to keep the mixture stirrable and prevent setup . Keeping the mixture hot , above the temperature where sodium sulfate transitions to a hydrated salt is required throughout the freebasing . After all the NaOH has been added , the mixture is kept warm and stirred for an additional ten minutes , and then extracted while still warm with succesive portions of methanol which takes up the hydrazine hydrate and water while leaving behind the anhydrous sodium sulfate byproduct . All of the methanol extracts should be done by mixing and decantation of the methanol
using four added portions about the same volume as the mixture being extracted .
Filtering will not work because of the air sensitivity of the hydrazine , and all manipulations should be done quickly
and stoppers put into place following transfers . Hydrazine is an efficient "getter" for oxygen and will actually pull a partial vacuum in a stoppered flask when it reacts with any oxygen in the headspace over the liquid .
The vapor pressure of the methanol fumes escaping helps provide a protective blanket against the air which is detrimental otherwise to hydrazine .

In the isolated methanolic hydrazine extract is dissolved a slight excess of
an equimolar amount of solid NaOH .

A corresponding slight excess molar amount of isopropyl nitrite is prepared separately .

When the methanol solution of hydrazine hydrate and NaOH is placed in a reaction
flask , setup for magnetic stirring and cooled by an ice bath , crystalline sodium azide
will precipitate in the cold mixture as isopropyl nitrite is gradually injected
below the surface near the bottom of the
stirred mixture . The reaction produces
pressure in the reaction vessel due to some transesterfication of the isopropyl nitrite to methyl nitrite . So the ground joints must be wired or clamped to prevent their being dislodged by the pressure . The pressure is regulated by
having a vent line immersed in water to
a depth sufficient that the head pressure
will just slightly be overcome and allow
a very slow bubbling from the end of the vent line . I made an improvised "tilt tube
manometer" for pressure regulation , by
duct taping a six foot length of 2 inch PVC
water pipe to the neck of a glass gallon jug and filled the entire thing with water .
The vent line was shoved down through
the pipe and to the bottom of the glass jug where the end of the vent line could be observed bubbling . By sitting the
jug on the ground and leaning the top
of the water filled PVC pipe against a wall
at whatever height was desired , the back
pressure on the reaction vessel could be regulated to allow only a slight venting
evident by observing the bubbling at the end of the vent line . Tilting the assembly closer to a horizontal position
lowers the venting pressure , while raising
it towards vertical raises the venting pressure . By use of this setup it is easy
to maintain a controlled and safe pressure
within the glass system .

The injection of the isopropyl nitrite into
the system was accomplished by using
a non-equalized addition funnel equipped
with a drip window and a teflon capillary
delivery tube . A few drops of methanol
was added to the isopropyl nitrite in the addition funnel and the methyl nitrite produced by transesterfication served to
pressurize the funnel after it was stoppered , the stopper retained by a spring clamp for any overpressure relief .
This setup allowed for slightly pressurized
delivery of the isopropyl nitrite , into the
cold and therefore lower pressurized reaction flask below .

A good yield of pure sodium azide was obtained by this method .
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[*] posted on 10-12-2004 at 11:34


Anybody knows if this reaction is possible?

NaNO3 + (H2N)2CO ==> NaN3 + 2 H20 + CO2

Perhaps it works if you melt urea and sodium nitrate together at 150°C. Sodium azide decomposes at 300°C.
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[*] posted on 10-12-2004 at 11:51


Oh, comon, why do you think it's possible? Any evidence for it?

You could throw together any number of chemicals together, and get soem theoretical endproduct, but it doesn't necessarily mean it happens for real.




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[*] posted on 10-12-2004 at 18:17


to produce sodium azide, firstly created a mixture of NaOH and pure ammonia solution. Nextly, bubble through this N2O (gas from the whip cream container)
NH3 + N2O --> HN3 + H2O
HN3 + NaOH --> NaN3 + H2O
Indeed...
Finaly, crystalize the deadly and volatile NaN3.:o




F. de Lalande and M. Prud'homme showed that a mixture of boric oxide and sodium chloride is decomposed in a stream of dry air or oxygen at a red heat with the evolution of chlorine.
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[*] posted on 10-12-2004 at 18:25


will not work halogen. NaOH in ammonia is simply NaOH in ammonia. THe nitrous oxide will only mix and not actually react.



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[*] posted on 10-12-2004 at 18:29


it's HN3 not NH3



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