Sciencemadness Discussion Board

Azides

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The_Davster - 9-5-2004 at 13:13

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.:P
Keep in mind I only have 2 weeks with this book, but if there is enough demand for info I will renew it.

halogen - 9-5-2004 at 15:56

Would there be such a compound as antimony triazide? If so, it would astound me... And what about ammonium azide?
I think it would decompose th Hydrogen and nitrogen rather violently.
NH4N3-->2N2+2H2

Azides of Antimony

The_Davster - 9-5-2004 at 16:29

"metallic Sb dissolves very slowly in hydrazoic acid, and owing to hydrolysis, no azide containing products can be isolated. Some organoantimony azides are known, such as the liquid (C6H5)2SbN3, which resembles the respective P and S compounds. A low azidized compound of Sb(V), the yellow crystalline SbCl4N3 explodes on mechanical and thermal shock. Thermal decomposition starts at 107C and leads at 131C to melting sometimes with exploding. The compound is obtained by azidation of antimony pentachloride with chlorine azide or with trimethylsilyl azide. Equally explosive is the yellow anion[SbCl5(N3)]- which is obtained as the crystalline potassium salt from SbCl5 and potassium azide in liquid SO2. The complex dissolves in water with hydrolysis and in polar organic solvents."

BromicAcid - 9-5-2004 at 16:43

Does your book have any information on Aluminum tetraazidoborate Al[B(N3)4]3 ? All I have found on this compound is that it is a very shock sensitive explosive but it has always been somewhat intriguing to me.

Ammonium azide

The_Davster - 9-5-2004 at 17:20

"Ammonium Azide
This compound, of the interesting empirical formula N4H4 has the properties of a typical ammonium salt. At 20C, 100mL water dissolve 20.16g; 100mL methanol, 3.27g; and 100mL ethanol, 1.06g. It is easily recrystallized from hot methanol or precipitated with ether.
Like ammonium chloride, N4H4 dissociates thermally below the melting point according to NH4N3<--> HN3 + HN3 , but the tendency here is so pronounced that the vapours are completely dissociated at room temperature, and the substance volatilizes quickly when left uncovered.
The thermal dissociation of N4H4 is frequently mistaken for sublimation. It has been reported with a note of surprise, for example, that the salt explodes when heated in a sealed system, but not in open air. These explosions stem from a pressure build up of free HN3 in the vapour phase. Likewise, older reports on the temperatures of thermal decomposition, sublimation, and deflagration do not discount the presence of free HN3.
N4H4 is made by simple metathetic in liquid, solid, or gaseous media which may involve distillation or precipation. For example equimolar amounts of ammonium chloride and sodium azide may be distilled with an equal quantity of water. At 160C pot temperature, the product volatilizes with water vapours and solidifies in the condenser tube which should, therefore, be at least 1 inch wide. Equally clean and safe is a gas phase reaction which requires however, the preparation of hydrazoic acid gas. The reaction takes place in a long, 1-inch-wide glass tube which has 2 inlet tubes with orifices 20 inches apart, and a vent. The HN3 gas, carried with nitrogen, and excess ammonia stream in and precipitate the product as fine needles. N4H4 is also precipitated when ammonia gas is bubbled into an ethereal hydrazoic acid solution. The product stays in solution when HN3 vapours, carried with nitrogen, are bubbled into aqueous ammonia.
The following procedures have also been reported as advantageous, but are in fact inferior: Larger batches were made by mixing equimolar amounts of sodium azide and ammonium acetate as saturated solutions; upon cooling to 5C, N4H4 separated in a low yield(aprox 25%). Additional crystallizations from the mother liquor were contaminated with sodium acetate. Or, a distillation method uses dimethylformamide as a vehicle to react and distill sodium azide and ammonium sulfate. The procedure is cumbersome because of clogging of the condenser could not be controlled satisfactorally, in spite of elaborate equipment . not recommended is a dry method in which sodium azide and ammonium nitrate are heat treated , and the product is sublimed off at 200C. The vapour phase contains free HN3 which tends to explode above room temperature. Reportedly , 5g batches were made safely, but a 50g batch exploded at 158C.
Alkylammonium azides, such as the tetramethyl salt, [(CH3)4N]N3 are accessible through mixing the respective iodides with silver azide or, less hazardously, by neutralizing the respective hydroxides with hydrazoic acids to pH 8. Generally, they are more stable then ammonium azide, as free HN3 is not formed through dissociation. They burn in a flame without explosion and are insensitive to mechanical and thermal shock."

The_Davster - 9-5-2004 at 17:32

Quote:
Originally posted by BromicAcid
Does your book have any information on Aluminum tetraazidoborate Al[B(N3)4]3 ? All I have found on this compound is that it is a very shock sensitive explosive but it has always been somewhat intriguing to me.

There is no specific info on Aluminum tetraazidoborate but there is a bit on the tetrazidoborate ion
"The properties of tetraazidoborate resemble those of normal boron azide. It is synthesized , aparently in a 2-stage reaction, from lithium borohydride and hydrazoic acid.
LiBH4 +4HN3--> LiB(N3)4+ 4H2.
excess ethereal hydrazoic acid is condensed onto a frozen(liquid nitrogen) ethereal LiBH4. The solid mixture is allowed to warm up ; between -116 and -80C, H2 is evolved and LiN3 precipitates.
LiH.BH3+HN3 --> LiN3+BH3+ H2
near 0C, H2 is again evolved and ether soluble LiB(N3)4 is formed.
LiN3+BH3+3HN3--> LiB(N3)4 +3H2
After pumping the solvent off, the product is obtained as a white solid."
One could probally go from there to Aluminum tetraazidoborate.

University

Quantum - 9-5-2004 at 18:49

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!:D

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]

The_Davster - 9-5-2004 at 19:22

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

azides :o

heksogen - 10-5-2004 at 00:53

I know that lead azide is made by mixing solutions of lead nitrate, sodium azide and dextrin and sodium azide is made by bubling nitrogen oxide throw molten sodium amide. My question is :
Are there any other ways to get sodium or hydrogen azide???

darkflame89 - 10-5-2004 at 01:44

I am fairly interested in azide compounds especially that of sodium azide and copper azide. Any extra info on that? What happens when they explode? Does the sodium azide form sodium and nitrogen gas?

chemoleo - 10-5-2004 at 07:54

rogue, that is an interesting book you have!
I think I shall have a look in our big Uni library myself soon.... you may be surprised i have only been there once or twice, as all the biochem stuff is in the local library...

Anyway - does your book say anything about azides of organic amines? Methylamine, ethylenediamine, etc? how about hydrazine, or hydroxylamine?


PS hexogen, yes there are other ways, but similarly difficult. One is with hydrazine/nitrite.
The info is somewhere around here, I am sure.

Mongo Blongo - 10-5-2004 at 09:31

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

The_Davster - 10-5-2004 at 15:26

Firstly, the sections on sodium, lead, copper and hydrogen azide are all about 10 pages long, too long for me to retype. I will try to get a friend to scan them and upload them somewhere.
Secondly:
"Hydrazine azide
Curtis made hydrazine azide, (NH2N5)N3 in 1891 from hydrazoic acid and hydrazine, both of which he had discovered in the two preceding years. Today, the compound has found application in rocket fuel technology.
N5H5 is a very hygroscopic, extremely soluble salt: at 23C, 100g water dissolve 190g. It also dissolves in methanol(6%) and ethano(1%); it is insoluble in ether. It is not sensitive to impact but explodes on heat shock; after melting at 70.5C it decomposes at about 90C. In a flame it burns without explosion. If hydrazoic acid is available, hydrazine azide is made by simple admixing the acid with an equimolar quantity of hydrazine, either by bubbling the HN3 gas or by using aqueous or ethereal HN3 solutions. In the latter case the hydrazine azide is precipitated. The preparation from sodium azide and hydrazine azide is more convienent. According to one source, 17g hydrazine sulfate, 17g sodium azide and 4g hydrazine are refluxed in 2L of n-butanol at 117C for 15min. The liquid phase is then separated and cooled to 5C when N5H5 is precipitated."

"Hydroxylamine azide
This compound, (NH3OH)N3 is made by neutralizing hydroxylamine with hydrazoic acid and is described as a white, volatile solid which is water soluble and melts at 66C."

Chemoleo, of the azides of organic amines, these were all that were in the book.

Azides of mercury

The_Davster - 10-5-2004 at 15:29

"Azides of Mercury
Mercury(II) azide, Hg(N3)2 is a colorless, crystalline explosive which detonates with high brisiance on friction, impact and heat shock. Its explosive sensitivity depends largely on the particle form, of which 2 distinct types have been qualitatively described. The first consisting of compact, small crystallites of 60-80 um diam., is relatively insensitive and has without mishap been coarsely powdered or ground in nujol; it explodes on impact of a 500g weight dropping from 65mm. The second in the form of long thin needles, explodes at the slightest provocation or even spontaneously.
Hg(N3)2 is somewhat photo sensitive and turns yellow in bright daylight, owing to the appearance of colloidal mercury. It also decomposes thermally with gas evolution starting at 212C, followed by discoloration at 220C and explosion at 300C. The compound is slightly soluble in cold water(.257g in 100g solution at 20C); in hot water it dissolves more readily, without noticeable hydrolysis. It also dissolves in ethanolamine, apparently without chemical reaction, and in hydrofluoric acid, as a cation complex. Upon evaporation of the acid, the azide appears unchanged.
Hg(N3)2 has been made by dissolving mercury(II) oxide in hydrazoic acid
HgO + 2HN3 à Hg(N3)2 +H20
To separate the product from unreacted HgO, the azide is dissolved by heating and then filtered. It recrystallizes as the above mentioned, highly sensitive needles which have to be handled with extreme caution; eg., a large particle, slowly sinking in a water-filled beaker, exploded without touching the bottom. Likewise, crystals adhering to the wall could not be removed without explosion. It is essential to move the liquid constantly with a stirrer made of soft material, as slow cooling of an unstirred solution leads invariably to explosion.
The compact crystal form is prepared more safely by precipitating at room temperature a concentrated solution of mercury(II) nitrate or chloride with sodium azide. The product may be separated by centrifuging.
Among complex mercury(II) azides a colorless, explosive dipyridne diazido mercury(II) of the possible structure [HgII(Py)2(N3)2]0 is precipitated when water is added to a solution of mercury(II) nitrate in pyridine. A triazidomercurate(II) [HgII(N3)3)- is obtained from mercury(II) nitrate and excess sodium azide in acid media and isolated as the tetraphenylphosphonium salt.
Like mercury(II) azide, mercury(I) azide is a colorless, solid explosive, which is precipitated from aqueous media as a crystalline powder of high sensitivity. It explodes with high brisance on impact of a 500g weigh dropping from 60mm(lead azide,430mm; silver azide, 410mm). Heated at 283C it explodes in 178 seconds, and a 292C in 75 seconds. Slow thermal decomposition leads to discoloration at 170C and, melting with decomposition at 230C, and ignition at 400C. Its photo sensitivity is higher than that of mercury(II) azide: exposed to daylight it turns yellow, then orange, brown, black, and finally separates droplets of gray mercury. The mechanism does not involve disproportionation of the Hg(I) state.
Thin, crystal needles should be avoided as they are extremely sensitive, and would, upon breaking, set off the whole batch. Small particles are obtained by rapidly precipitating a concentrated mercury(I) nitrate solution with sodium azide and centrifuging the product."

Sorry Mongo Blongo, nothing on Glycidyl Azide.

[Edited on 10-5-2004 by rogue chemist]

Mongo Blongo - 11-5-2004 at 10:11

Thanks dude!:)

vulture - 11-5-2004 at 10:34

Some info on hydrazinium azide hydrazinate [N<sub>2</sub>H<sub>5</sub>]<sup>+</sup>[N<sub>3</sub>]<sup>-</sup> . N<sub>2</sub>H<sub>4</sub>
from the Journal of Propellants, Explosives and Pyrotechnics.

Attachment: hydrazinium azide hydrazinate.pdf (87kB)
This file has been downloaded 5557 times


Hydrazoic acid

froot - 17-5-2004 at 12:23

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, (2) by reaction of NH3 and Na metal heated to about 300 deg C. (sodamide formed) and then treating the residue with dry NO gas at about 200 deg C. The product is dissolved in water, then acidified and distilled as above. -brief but riveting!

Thought it would be worth sharing. The first method has my attention!

a_bab - 18-5-2004 at 06:02

Rougue Chemist, how about lead azide ? I made about 10 grams about two years ago and I'm curious about the storage problems. So far so good, but still...I heard about the recrystalisation in storage which tends to lead to bigger and less stable crystals.

Polverone - 18-5-2004 at 10:49

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.

froot - 18-5-2004 at 12:22

I thought as much.
Quite a nasty blooper for an encyclopoedia to have if that is wrong!

The_Davster - 19-5-2004 at 14:30

Quote:
Originally posted by a_bab
Rougue Chemist, how about lead azide ? I made about 10 grams about two years ago and I'm curious about the storage problems. So far so good, but still...I heard about the recrystalisation in storage which tends to lead to bigger and less stable crystals.


I am getting my friend with a scanner to scan this section as it is too long to retype. I should have it here by the weekend. How do I upload to the scipics directory?

Lestat - 19-5-2004 at 14:46

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.


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_Davster - 1-6-2004 at 15:14

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...

JustMe - 1-6-2004 at 16:18

Chlorazide N3Cl is described as a colorless very explosive gas obtained by the action of sodium hypochlorite solution and boric acide on sodium azide.

Iodazide N3I is a pale-yellow explosive solid obtained by the action of iodine on silver azide.

My old Textbook of Inorganic Chemistry also lists a number of other exotic azides: Cyanogen azide (CN-N3)2, sulphuryl azide N3-S02-N3 and azido-dithiocarbonic acid N3-CS-SH. But it doesn't mention any routes for synthesis.

The_Davster - 1-6-2004 at 19:09

I really should not have returned that book to the library, when I go again next time I will look up the azides you mentioned, JustMe.

a_bab - 3-6-2004 at 06:54

Rogue chemist, thank you very much indeed.

The_Davster - 3-6-2004 at 19:17

Your welcome a_bab.

Sodium azide scans have now been uploaded. Same spot as before

hey Froot,

kyanite - 30-6-2004 at 15:21

hey Froot, I have the same encyclopedia, but it's the 5th edition, i don't know which do you have. Anyways, this is what my encyclopedia says:

Hydrazoic acid is formed (1) by reaction of sodium nitrate with molten sodamide, (2) by reaction of nitrous oxide with molten sodamide, (3) by reaction of nitrous acid and hydrazinium ion, (4) by oxidation of hydrazinium salts, (5) by reaction of ethyl nitrite with NaOH solution and acidifying.
Is this what you mean?

froot - 1-7-2004 at 09:33

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. :o Is there any way that this procedure for hydrazoic acid is possible?

[Edited on 1-7-2004 by froot]

S.C. Wack - 1-7-2004 at 13:02

No. Polverone's answer still stands.

This is a common problem with many short synthetic descriptions. They are too short to be of any use and are misleading. Kirk-Othmer also has many examples of this.

I think that the original articles on hydrazine + NaOH + alkyl nitrites are in Ber., 41 (1908)
Thiele- p. 2681
Stolle- p. 2811

Also see the excellent US patents:
1628380, 5208002, 5098597, and any others that you might find by doing a word or classification search.

The_Davster - 23-8-2004 at 13:42

For those of you who still want this book, the preparation of the azides section is on the roguesci FTP.
I was not the one who upped it there, one of their members did.

mick - 24-8-2004 at 09:42

Has anyone managed to get the sodium azide out of a car air bag detonater. I thought it was sodium azide they used but I do not know how much.
The bit I have got is if you pass N2O over the melted sodamide you get sodium azide and water, the water should be blown away. Sodium azide when distilled with 50% sulphuric acid yields hydrazoic acid.
Mick

Boils at 37 0C

[Edited on 24-8-2004 by mick]

hodges - 24-8-2004 at 14:28

Keep in mind that the azides are more poisonous even than cyanides! That's the reason I don't mess with them.

Nitramine - 26-8-2004 at 09:42

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]

Blaster - 26-8-2004 at 14:09

On that note does anyone know how the NaN3 is initiated in air bags?

I have some lab grade NaN3 and you have to heat the hell out of it to get it to deflagrate - it doesn't detonate in my experience, unlike the heavy metal salts. I haven't tried heating a large amount though.

Further to a_bab's question about storage of lead azide, I have a large quantity (50g+ dextrinated) that has been stored in the dark under water, for safety, for over 10 years and it still detonates like the day it was made!

Lead azide has always been the detonator of choice for me - its incredibly powerful and so easily made.
Hint for all those searching for NaN3 - its a commonly used preservative in biology labs.

FrankRizzo - 24-9-2004 at 21:24

Nitramine,

Did you ever find an archive copy of the webpage detailing extraction of NaN3 from airbag pellets?

tokat - 26-9-2004 at 00:48

triazole

1. Procedure
(Note 1)
A. 1-Formyl-3-thiosemicarbazide. Four hundred milliliters of 90% formic acid contained in a 2-l. round-bottomed flask is heated on a steam bath for 15 minutes, and then 182 g. (2 moles) of colorless thiosemicarbazide (Note 2) is added. The mixture is swirled until the thiosemicarbazide dissolves. The heating is continued for 30 minutes, during which time crystalline 1-formyl-3-thiosemicarbazide usually separates. Boiling water (600 ml.) is added, and the milky solution that results is filtered through a fluted filter paper. After standing for 1 hour, the filtrate is cooled in an ice bath for 2 hours, and the 1-formyl-3-thiosemicarbazide that separates is collected by suction filtration and air-dried overnight. It weighs 170–192 g. (71–81%) and melts at 177–178° with decomposition.
B. 1,2,4-Triazole-3(5)-thiol. A solution of 178.5 g. (1.5 moles) of 1-formyl-3-thiosemicarbazide and 60 g. (1.5 moles) of sodium hydroxide in 300 ml. of water in a 2-l. round-bottomed flask is heated on a steam bath for 1 hour. The solution is cooled for 30 minutes in an ice bath and then is treated with 150 ml. of concentrated hydrochloric acid. The reaction mixture is cooled in an ice bath for 2 hours, and the 1,2,4-triazole-3(5)-thiol that precipitates is collected by suction filtration. The thiol is dissolved in 300 ml. of boiling water and the solution is filtered through a fluted filter paper. The filtrate is cooled in an ice bath for 1 hour, and the thiol is collected by suction filtration and air-dried overnight. The 1,2,4-triazole-3(5)-thiol weighs 108–123 g. (72–81%) and melts at 220–222°.
C. 1,2,4-Triazole. Caution! This preparation should be carried out in a ventilated hood to avoid exposure to noxious fumes.
A mixture of 300 ml. of water, 150 ml. of concentrated nitric acid, and 0.2 g. of sodium nitrite (Note 3) is placed in a 2-l. three-necked flask equipped with a stirrer and a thermometer. The stirred mixture is warmed to 45°, and 2 g. of 1,2,4-triazole-3(5)-thiol is added. When oxidation starts, as indicated by the evolution of brown fumes of nitrogen dioxide and a rise in temperature, a bath of cold water is placed under the reaction flask to provide cooling and an additional 99 g. (total, 101 g.; 1 mole) of 1,2,4-triazole-3(5)-thiol is added in small portions over the course of 30–60 minutes. The rate of addition and the extent of cooling by the water bath are so regulated as to keep the temperature close to 45–47° all during the addition. The water bath is kept cold by the occasional addition of ice.
When the addition is completed, the bath is removed and stirring is continued for 1 hour while the reaction mixture gradually cools to room temperature. Sodium carbonate (100 g.) is added in portions, followed by the cautious addition of 60 g. of sodium bicarbonate (Note 4). The water is removed from the slightly basic solution by heating the solution in a 3-l. round-bottomed flask under reduced pressure on a steam bath. To aid in removing the last traces of water, 250 ml. of ethanol is added to the residue and the mixture is heated under reduced pressure on a steam bath until it appears dry (Note 5).
The residue is extracted twice with 600 ml. of boiling ethanol to separate the triazole from a large amount of inorganic salts. This extract is evaporated to dryness on a steam bath under reduced pressure, and the resulting residue is extracted with two 500-ml. portions of boiling ethyl acetate. The ethyl acetate extract is evaporated to dryness on a steam bath under reduced pressure. The crude 1,2,4-triazole remaining in the flask is dissolved by heating it with 50 ml. of absolute ethanol, and then 1 l. of benzene is added. The mixture is heated under reflux for 15 minutes, and the hot solution is filtered through a fluted filter paper. This extraction procedure is repeated. The two extracts are combined, cooled in an ice bath for 30 minutes, and filtered to remove colorless crystals of 1,2,4-triazole (m.p. 120–121°), weighing 28–30 g. after being dried in air. About 300 ml. of the filtrate is removed by slow distillation through a Claisen still-head to remove the bulk of the ethanol. The residual solution is cooled in an ice bath for 30 minutes and filtered to separate an additional 8–10 g. of colorless 1,2,4-triazole, m.p. 119–120°. The total weight of 1,2,4-triazole is 36–40 g. (52–58% yield).
2. Notes
1. This procedure is no longer regarded as the best available for the preparation of 1,2,4-triazole. See Discussion section.
2. The thiosemicarbazide must be of good quality or the yield and quality of 1-formyl-3-thiosemicarbazide will suffer. The thiosemicarbazide supplied by Olin Mathieson Chemical Corporation, obtained as a colorless free-flowing powder, can be used without purification.
3. The use of sodium nitrite helps to avoid an induction period.
4. A large flask is used to contain the vigorous effervescence that occurs upon the addition of carbonate. The final pH should be near 7.5, and it is reached after the addition of bicarbonate no longer causes bubbling.
5. Prolonged heating under reduced pressure should be avoided, since 1,2,4-triazole tends to sublime

tokat - 26-9-2004 at 00:51

4-dodecylbenzenesulfonyl azides

1. Procedure
Caution! Although the mixture of dodecylbenzenesulfonyl azides is the safest of a group of diazo transfer reagents,2 one should keep in mind the inherent instability, shock sensitivity, and explosive power of azides. All users should exercise appropriate caution.
4-Dodecylbenzenesulfonyl chlorides. A 250-mL, three-necked, round-bottomed flask, equipped with a mechanical overhead stirrer, a Claisen adapter bearing an immersion thermometer, a pressure-equalizing addition funnel, and reflux condenser, is charged with a solution of 60.00 g (0.184 mol) of dodecylbenzenesulfonic acids (Note 1) and 8.64 mL of dimethylformamide (DMF) in 60 mL of hexane . Stirring is initiated while the mixture is heated to 70°C using a heating mantle, and 22.1 mL (36.24 g, 0.304 mol) of thionyl chloride (Note 2) is added at a rate to maintain controlled reflux (Note 3). The required addition time is about 1 hr. The dark solution is heated an additional 2 hr at 70°C and cooled to 40°C (Note 4). While still warm (40°C), the mixture is transferred to a 250-mL separatory funnel, and the dark lower layer is separated from the hexane solution (Note 5). The hexane layer is cooled to 25°C and washed with 60 mL of aqueous 5% sodium bicarbonate solution (Note 6). The bicarbonate wash is back extracted with 36 mL of hexane and the combined hexane layers are treated with 3 g of carbon (Note 7), (Note 8) and stirred for 2 hr at 25°C. The carbon is removed by filtration and the cake is washed with three portions (12-mL each) of hexane. The combined hexane layers plus the hexane washes are used to prepare the azide.
4-Dodecylbenzenesulfonyl azides. A 500-mL, three-necked, round-bottomed flask fitted with a mechanical overhead stirrer is charged with the hexane solution from step A. To this solution is added a solution of 11.6 g (0.178 mol based on the total solids from the sulfonyl chlorides above) of sodium azide (NaN3) in 100 mL of water and 2.0 g of phase transfer catalyst (Aliquat 336) (Note 9). Stirring is initiated, and the reaction progress is monitored by thin layer chromatography (Note 10). Approximately 4 hr at 25°C is required to complete the reaction. The two-phase mixture is transferred to a 500-mL separatory funnel and the aqueous layer is removed. The hexane layer is washed with 100 mL of aqueous 5% sodium bicarbonate solution and dried over 28 g of anhydrous sodium sulfate. The drying agent is removed by suction filtration, and the cake is washed with 20 mL of hexane. The concentration and purity of the 4-dodecylbenzenesulfonyl azides are best determined by evaporation of a small sample to an oil of constant weight with visible spectrophotometric assay for the azide (Note 11). The hexane solution of dodecylbenzenesulfonyl azides, when standardized as above (Note 11), can be used as obtained for most applications. However, if desired, careful concentration of the hexane solution under reduced pressure at room temperature affords 58.2–61.4 g (90–95%) of the oily mixture of dodecylbenzenesulfonyl azides; corrected for the assay of the azides the yield is usually 95% (Note 12) and (Note 13).
2. Notes
1. Dodecylbenzenesulfonic acids, a 97% mixture of branched chain isomers, was purchased from Spectrum Chemical Mfg. Corp.
2. Reagent grade thionyl chloride from Fisher Scientific Co. was used.
3. An excess of thionyl chloride–dimethylformamide catalyst is used to prevent formation of sulfonic anhydrides. A stoichiometric amount of thionyl chloride gives a much reduced yield.
4. The progress of the reaction is monitored by thin layer chromatography. A 0.1-mL sample is removed, evaporated to dryness and dissolved in 2 mL of hexane. The solution is spotted on an Analtech silica GF plate (8 cm × 2.5 cm) and developed in hexane/methylene chloride (4/1). Visualization by UV light shows Rf = 0.4 for the sulfonyl chlorides.
5. If allowed to cool to 25°C, the dark layer may solidify, hampering the separation. This very acidic layer is the excess thionyl chloride/DMF complex. It should be handled with proper protection in a ventilated area To facilitate visual identification of the layers, the checkers added about 25 mL of hexane.
6. The pH of the bicarbonate wash is a reflection of the efficiency with which the dark lower layer has been removed. In the course of a dozen runs, this pH ranged from 5.5 to 7.1. If the pH of the wash is below 5.5, a second wash with bicarbonate is necessary.
7. Nuchar SA carbon from Westvaco Co. was used.
8. It is essential that the carbon treatment be carried out within a few hours. Experiments where this treatment was delayed for 16 hr invariably produced an azide mixture of lower purity (85%) and lower yield (80%). Although the sulfonyl chlorides hydrolyze only slightly (1–2%) in wet hexane in 24 hr, that amount of sulfonic acids in the presence of the phase transfer agent catalyzes the hydrolysis of sulfonyl chlorides. After treatment with carbon, the hexane solution of sulfonyl chlorides can be stored for several weeks in the refrigerator with little or no adverse effect on the next step.
9. Aliquat 336 (tri-n-alkylmethylammonium chloride) was obtained from Aldrich Chemical Company, Inc. The material is a mixture of C8 and C10 chains with C8 predominating. There is a slight initial exothermic reaction on adding the phase transfer catalyst. Intermittent cooling with a cold water bath is required to keep the temperature below 35°C.
10. A sample of the hexane layer from the reaction mixture is diluted 10 fold with hexane, spotted and developed as described in (Note 4). Visualization by UV light shows Rf = 0.3 for sulfonyl azides.
11. The assay for sulfonyl azides is adapted from the method of Siewinski, et al.3 The azide content of the hexane solution was assayed as follows to determine the contained yield:
1. Standard Curve:
Stock solution: 80 mg of NaN3 diluted to the mark in a 100-mL volumetric flask with 0.1 N NaOH-MeOH.
Procedure: Into a series of four, 100-mL volumetric flasks, transfer 5, 7, 10 and 15 mL respectively of the stock solution. Into a 100-mL volumetric labelled blank, pipet 10 mL of 0.1 N NaOH-MeOH solution. To all add 2 drops of 0.1% ethanolic phenolphthalein indicator solution, and 20 mL of aqueous 1.5% sodium sulfate (Na2SO4). Acidify each, in turn, to the phenolphthalein end point with 1 N hydrochloric acid and immediately add 25 mL of 1 M ferric ammonium sulfate [Fe(NH4)(SO4)2] solution. Dilute to the mark with 1.5% Na2SO4. Let stand 10 min, then read absorbance at 458 nm. Plot absorbance vs. concentration.
2. Sample:
Pipet 5 mL of the hexane solution containing 4-dodecylbenzenesulfonyl azides into a 100-mL volumetric flask and dilute to the mark with methanol. Pipet 5 mL of this solution into a small stoppered flask. Add 2 mL of aqueous 1 N potassium hydroxide solution and heat at 75°C for 20 min. Allow to cool to room temperature, add 2 drops of 0.1% phenolphthalein solution, and 10 mL of 1.5% Na2SO4. Shake, then transfer quantitatively to a 60-mL separatory funnel. Add 10 mL of butanol (or isoamyl alcohol) to the sample flask, shake, then transfer to the separatory funnel. Shake the funnel, let the layers separate, then remove the bottom (H2O) layer into a 100-mL volumetric flask. Add an additional 10 mL of 1.5% Na2SO4 to the alcohol layer in the separatory funnel, shake, let the layers separate, then transfer the water layer to the volumetric flask. Neutralize the combined water layers to the phenolphthalein end point with 1 N hydrochloric acid, then immediately add 25 mL of Fe(NH4)(SO4)2. Dilute to the mark with 1.5% Na2SO4 solution, let stand 10 min, then read absorbance at 458 nm. Read azide concentration against the NaN3 calibration curve.
12. The checkers determined the yield by evaporation of the hexane solution to constant weight (3–10 hr at 0.1 mm). The yields cited are based on the assumption that the 3% impurity in the starting sulfonic acids is not present in the final product. The checkers found the material obtained upon concentration, to be sufficiently pure for use without further purification.
13. The spectroscopic data for the mixture of four isomeric secondary dodecylbenzenesulfonyl azides (2.5:1.6:1.6:1.0) is as follows: 1H NMR (400 MHz, CDCl3) δ: 0.70–1.00 (m, 6 H), 1.00–1.50 (m, 12 H), 1.50–1.80 (m, 6 H), 2.90–2.50 (m, 1H), 7.25–7.45 (m 2 H), 7.87 (m 2 H); 13C NMR (100 MHz, CDCl3) δ: 12.07, 13.94, 14.02, 14.05, 14.07, 14.10, 20.63, 21.89, 22.50, 22.61, 22.63, 22.65, 22.69, 27.18, 27.48, 27.52, 27.58, 29.15, 29.26, 29.30, 29.32, 29.44, 29.46, 29.49, 29.51, 29.57, 29.61, 29.72, 31.69, 31.82, 31.83, 31.88, 31.91, 36.21, 36.34, 36.60, 36.61, 36.64, 38.06, 38.85, 40.24, 46.11, 46.38, 48.15, 127.55, 127.66, 128.33, 128.93, 129.01, 135.82, 135.85, 154.56, 154.82, 154.87, 156.09; IR (film) 2126 cm−1.
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
4-Dodecylbenzenesulfonyl chlorides have been prepared from the corresponding acids using chlorosulfonic acid,4 phosphorus oxychloride,2 and thionyl chloride.5 The use of catalytic amounts of DMF in conjunction with thionyl chloride is based on the work of H. Bosshard, et al.6 The insolubility of the DMF/thionyl chloride complex in the reaction solvent permits easy removal at the end of reaction. Extraction with dilute base removes the last trace of acids and the solution is pure enough for the next step.
The method described above for the preparation of the mixture of 4-dodecylbenzenesulfonyl azides is new and based on the work of Bollinger and Hazen.5,7 Sulfonyl azides have been prepared by diazotizing substituted sulfonyl hydrazides,8 and treating sulfonyl halides in methanol-water,9 ethanol-water,10 acetone,2,5,7 or acetone-water solutions11 with aqueous or solid sodium azide.5,7,12 Use of phase transfer catalysis for the preparation of sulfonyl azides is new, simple and effective. It avoids solvent changes and permits isolation of a hexane solution of sulfonyl azides without concentration.
The use and advantages of 4-dodecylbenzenesulfonyl azides as a diazo transfer agent are fully discussed by Hazen, Weinstock, Connell, and Bollinger.7 In contrast to p-toluenesulfonyl azide, that has the shock sensitivity of tetryl (N-methyl-N-2,4,6-tetranitroaniline) and the explosiveness of TNT, the mixture of 4-dodecylbenzenesulfonyl azides exhibits no shock sensitivity at the highest test level (150 kg cm) and 24% of the heat of decomposition measured in cal/g. p-Toluenesulfonyl azide appears as a diazo transfer agent in Org. Synth., Coll. Vol. V 1973, 179; VI, 1988, 389, 414 and its preparation is reported in the first of these. Two explosions during its preparation have been reported.13,14
This preparation is referenced from:

tokat - 26-9-2004 at 00:54

ACETAMIDE


Submitted by G. H. Coleman and A. M. Alvarado.
Checked by H. T. Clarke and E. R. Taylor.
1. Procedure
In a 5-l. flask is placed 3 kg. (2860 cc., 50.0 moles) of glacial acetic acid and to this is added a weight of ammonium carbonate corresponding to 400 g. (23.5 moles) of ammonia (Note 1). The flask is fitted with a one-hole stopper holding an efficient fractionating column 90 cm. long with condenser and receiver. An air condenser 150–200 cm. long may be employed. The mixture in the flask is heated to gentle boiling and the flame so regulated that the rate of distillation does not exceed 180 cc. per hour. The distillation is continued in this way for eight to ten hours, until the temperature at the head of the column reaches 110°. The distillate, which is a mixture of water and acetic acid, amounts to 1400–1500 cc. The receiver is changed, the flame under the flask is gradually increased, and the distillation is continued at about the same rate until the temperature at the head of the column rises to 140°. The distillate, which amounts to 500–700 cc., is largely acetic acid and may be used in the next run.
The contents of the flask are transferred to a 2-l. flask for fractional distillation (p. 130), having a column 40–50 cm. long, and distilled under atmospheric pressure, using an air condenser. The fraction boiling below 210°, amounting to 250–300 cc., is collected separately. The material remaining in the flask is nearly pure acetamide and may all be distilled, 1150–1200 g. passing over at 210–216°. By redistilling the fraction boiling below 210°, the yield may be increased to 1200–1250 g. (87–90 per cent of the theoretical amount). The acetamide thus obtained is pure enough for most purposes, but if a purer product is desired it may be recrystallized from a mixture of benzene and ethyl acetate; 1 l. of benzene and 300 cc. of ethyl acetate are used for 1 kg. of acetamide (Note 2). Colorless needles melting at 81° are thus obtained (Note 3). The solvent and the acetamide it contains may be recovered by distillation.
2. Notes
1. Ammonium carbonate of commerce is often extremely impure, and care must be taken to obtain a representative sample for the determination of the ammonia content by titration with standard acid. The ammonium carbonate used in this preparation contained 27.2 per cent of ammonia, and 1470 g. was used in each run.
2. Crystallization of acetamide, by solution in hot methyl alcohol (0.8 cc. per g.) and dilution with ether (8–10 cc. per g.), has been recommended as the best method of purification.1
3. As acetamide is somewhat hygroscopic, it cannot be exposed to the air unless precautions are taken to have the air dry.
3. Discussion
Acetamide can be prepared by the rapid distillation of ammonium acetate;2 by heating ammonium acetate in a sealed tube and distilling the product;3 by treating acetic anhydride with ammonia;4 by heating a mixture of ammonium chloride and sodium acetate to 240°;5 by the action of cold aqueous ammonia on ethyl acetate;6 by boiling a mixture of glacial acetic acid and ammonium thiocyanate for four days;7 by saturating glacial acetic acid with dry ammonia and then refluxing;8 by distillation of ammonium acetate through a reflux condenser filled first with glacial acetic acid and then with aniline until the temperature of the mixture reaches 220°;9 by passing a stream of ammonia through heated acetic acid;10 and from formamide and hydrogen at 200–500°.11
The procedure described is based on the method of Noyes and Goebel,12 in which equimolecular proportions of ammonium acetate and acetic acid are heated together, the acetic acid having been shown to accelerate both the dehydration of ammonium acetate and the hydrolysis of acetamide.

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tokat - 26-9-2004 at 00:58

DIAZOMETHANE
[Methane, diazo-]


Submitted by James A. Moore and Donald E. Reed1.
Checked by D. J. Pasto and E. J. Corey.
1. Procedure
Caution! Diazomethane is toxic and explosive. The operation must be carried out in a good hood with an adequate shield (Note 1).
An efficient condenser (60 cm. or longer) is fitted with an adapter to which is sealed a length of 9-mm. tubing extending nearly to the bottom of a 5-l. round-bottomed flask, which serves as the distillation receiver (Note 2) and (Note 3). The adapter should be connected to the receiver with a two-hole stopper carrying a drying tube if anhydrous diazomethane is desired. The receiver is placed in a well-mixed ice-salt mixture, and sufficient anhydrous ether (about 200 ml.) is added to cover the tip of the adapter.
In a 5-l. round-bottomed flask are placed 3 l. of U.S.P. solvent grade ether, 450 ml. of diethylene glycol monoethyl ether (Note 4), and 0.6 l. of 30% aqueous sodium hydroxide solution (Note 5). The mixture is chilled in an ice-salt bath to 0° (Note 6), and 180 g. (0.5 mole) of N,N'-dimethyl-N,N'-dinitrosoterephthalamide (70% in mineral oil) (Note 7) is added in one portion. The flask is immediately transferred to a heating mantle and connected by a gooseneck to the condenser. The yellow color of diazomethane appears in the receiver almost immediately. About 2 l. of ether is distilled in 2–2.5 hours (Note 8); the distilling ether is practically colorless at this point. The tip of the adapter should be kept just below the surface of the distillate during the distillation. The distillate contains 0.76–0.86 mole (76–86%) (Note 9) and (Note 10) of diazomethane as determined by titration.2 When the apparatus has been protected with a drying tube, the diazomethane is suitable for reaction with an acid chloride without further drying.
2. Notes
1. Diazomethane is not only toxic but also potentially explosive. Hence one should wear heavy gloves and goggles and work behind a safety screen or a hood door with safety glass, as is recommended in the preparation of diazomethane described by De Boer and Backer.3 As is also recommended there, ground joints and sharp surfaces should be avoided. Thus all glass tubes should be carefully fire-polished, connections should be made with rubber stoppers, and separatory funnels should be avoided, as should etched or scratched flasks. Furthermore, at least one explosion of diazomethane has been observed at the moment crystals (sharp edges!) suddenly separated from a supersaturated solution. Stirring by means of a Teflon-coated magnetic stirrer is greatly to be preferred to swirling the reaction mixture by hand, for there has been at least one case of a chemist whose hand was injured by an explosion during the preparation of diazomethane in a hand-swirled reaction vessel.
It is imperative that diazomethane solutions not be exposed to direct sunlight or placed near a strong artificial light because light is thought to have been responsible for some of the explosions that have been encountered with diazomethane. Particular caution should be exercised when an organic solvent boiling higher than ether is used. Because such a solvent has a lower vapor pressure than ether, the concentration of diazomethane in the vapor above the reaction mixture is greater and an explosion is more apt to occur.
Most diazomethane explosions occur during its distillation. Hence diazomethane should not be distilled unless the need justifies it. An ether solution of diazomethane satisfactory for many uses can be prepared as described by Arndt,2 where nitrosomethylurea is added to a mixture of ether and 50% aqueous potassium hydroxide and the ether solution of diazomethane is subsequently decanted from the aqueous layer and dried over potassium hydroxide pellets (not sharp-edged sticks!). When distilled diazomethane is required, the alternative procedure of De Boer and Backer3 is particularly good because at no time is much diazomethane present in the distilling flask.
Both the toxicity and explosion hazards associated with diazomethane are discussed by Gutsche.4
2. If it is desired to determine the yield of diazomethane by titration, the receiver should be calibrated so that the volume of the distillate can be measured without the necessity of transferring to a graduated vessel.
3. The submitters have used equipment having all connections made with ungreased 29 / 42 ground-glass joints. This is contrary to previously recommended practice (Note 1). The submitters feel that ground-glass joints do not represent an added hazard, and that their use expedites the completion of consecutive runs. In the course of many preparations, however, a film of polymethylene was found to accumulate on the joints and prevent a tight fit. This film can be removed by a brief treatment with hot concentrated alkali and vigorous rubbing.
In some forty preparations made by the submitters, one explosion occurred which was attributed to the cracking of the adapter tube during the distillation. The adapter and the drying tube were disintegrated, but the receiver and the contents of the distilling flask were not affected, indicating a local detonation that was not sustained.
The checkers did not use glassware with ground-glass joints. New unmarked flasks and condenser were used which were connected together with fire-polished glass tubing and rubber stoppers.
4. Practical grade 2-(2-ethoxyethoxy)ethanol (Matheson, Coleman and Bell) can be used without further treatment. In a few preparations, the submitters encountered difficulty with the formation of a very stiff gel of disodium terephthalate in the flask during distillation. In one case, this difficulty was traced to the use of an old bottle of 2-(2-ethoxyethoxy)ethanol from another source.
This relatively large volume of cosolvent was found to give optimum yields. The submitters have found that the evolution of diazomethane from a stirred suspension of the reagent in ether and 40% aqueous sodium hydroxide is extremely slow and incomplete.
5. The use of more concentrated solutions of potassium hydroxide gave somewhat lower yields.
6. Caution! It is extremely important that the flask contents be cooled to at least 0°. The reaction is rapid and a considerable amount of diazomethane is generated at this temperature.
7. This material is available from Eastman Organic Chemicals and Aldrich Chemical Company. It is also available from E. I. du Pont de Nemours and Company, who use the trade name Nitrosan for it. The 30% white mineral oil acts as a stabilizer. The material may be stored indefinitely at room temperature. It sometimes turns green on long standing, but this does not affect the yield of diazomethane (private communication from B. C. McKusick).
8. The yield of diazomethane is slightly lower if the distillation is carried out more slowly.
9. The average yield in some thirty runs was over 80%; yields as high as 95% have been obtained. It is probable that a second receiver in series would permit the recovery of a small additional amount of diazomethane.
10. The checkers decomposed the small amount of diazomethane remaining in the reaction flask by careful addition of 100 ml. of acetic acid before disposal.
3. Discussion
Diazomethane has been prepared by the action of base o nitrosomethylurea,2 nitrosomethylurethane,5 N-nitroso-β-methylaminoisobutyl methyl ketone,6 p-tolylsulfonylmethylnitrosamide,3 and N-nitroso-N-methyl-N'-nitroguanidine.7 8
4. Merits of Preparation
The great advantages of the present method are the availability, moderate cost, and high stability of the nitrosamide, and the suitability for large-scale preparations. The procedure is rapid and simple, and the yields are consistently higher than in any other method tried by the submitters.
This preparation is referenced from:

tokat - 26-9-2004 at 00:59

INDAZOLE


Submitted by Emily F. M. Stephenson
Checked by C. F. H. Allen, C. V. Wilson, and Jean V. Crawford.
1. Procedure
A. o-Hydrazinobenzoic acid hydrochloride. In a 2-l. beaker, provided with a stirrer and a low-temperature thermometer, and cooled in an ice-salt bath, are placed 42 g. (0.31 mole) of anthranilic acid and 300 ml. of water. The stirrer is started, and 340 ml. of concentrated hydrochloric acid (sp. gr. 1.18) is added in one portion; the anthranilic acid dissolves, and its hydrochloride begins to separate almost immediately. After the mixture has been cooled to 0°, a solution of 21.6 g. (0.31 mole) of technical sodium nitrite in 210 ml. of water is added from a dropping funnel, the tip of which extends below the surface of the suspension, at such a rate that the temperature never rises above 3°. The addition requires about 30 minutes; stirring is continued for 15 minutes longer, and at the end of this period a positive test with starch-iodide paper should be obtained (Note 1). The clear brown solution is then diluted with 150 ml. of ice water.
In a 12-l. flask, equipped with a low-temperature thermometer and surrounded by an ice-salt bath, a solution of sulfurous acid is prepared by saturating 2.4 l. of water at 0–5° with sulfur dioxide from a cylinder. A brisk stream of the gas is continued (Note 2) while the cold diazonium salt solution is added in about 150-ml. portions over a 30-minute period and the temperature is maintained at 5–10°; the reaction mixture assumes a dark orange color (Note 3). The cooling bath is removed, but sulfur dioxide is passed into the mixture for an additional 30 minutes. After the mixture has been allowed to stand for 12 hours at room temperature, 3 l. of concentrated hydrochloric acid (sp. gr. 1.18) is added; the o-hydrazinobenzoic acid hydrochloride separates at once. The mixture is chilled to 0–5° and filtered through a precooled Büchner funnel; the product is washed with two 50-ml. portions of ice-cold dilute (1:1) hydrochloric acid. The yield is 50–51 g. (86–88%); the salt melts at 194–195° with decomposition (Note 4) and is suitable for the next step without further purification (Note 5).
B. Indazolone. In a 2-l. round-bottomed flask to which a reflux condenser is attached are placed 47.1 g. (0.25 mole) of o-hydrazinobenzoic acid hydrochloride, 1.25 l. of water, and 12.5 ml. of concentrated hydrochloric acid (sp. gr. 1.18). The mixture is refluxed for 30 minutes. The resulting pale yellow solution is transferred in two portions to a 23-cm. evaporating dish and concentrated on the steam bath to about one-fourth its original volume. The indazolone separates at an early stage of the evaporation but redissolves as the concentration of acid increases. Sodium carbonate is added to the warm solution in small portions until the acid is neutralized (Note 6), and the suspension is allowed to stand for 2 hours. The nearly colorless indazolone is removed by filtration, washed with two 25-ml. portions of cold water, and air-dried. The yield of product, m.p. 246–249°, is 30–33 g. (90–98%) (Note 7).
C. 3-Chloroindazole. In a 200-ml. flask connected by a glass joint to an air condenser protected by a drying tube are placed 26.8 g. (0.2 mole) of dry indazolone and 15.8 g. (16 ml., 0.2 mole) of dry pyridine (Note 8); 46.1 g. (27.6 ml., 0.3 mole) of phosphorus oxychloride is then added, with shaking, over a 10-minute period. Heat is evolved, and acid fumes are generated. The mixture is heated with occasional shaking in an oil bath, which is maintained at 128–130° for 1 hour and at 130–140° for 4 hours. The clear brown solution is then cooled to 70° and poured, with hand stirring, upon 500 g. of cracked ice. This mixture is allowed to stand for 24 hours. The pale buff solid is removed, washed on the filter, first with 100 ml. of 0.5 N hydrochloric acid and then with 40 ml. of cold water, and air-dried (Note 9). The 3-chloroindazole is crystallized from 3 l. of 20% ethanol. The yield is 21–22.5 g. (68–74%) of material melting at 148–148.5° (Note 10).
D. Indazole. In a 300-ml. flask are placed 15.3 g. (0.1 mole) of 3-chloroindazole, 18.6 g. (0.15 mole) of red phosphorus, and 100 ml. of constant-boiling hydriodic acid (sp. gr. 1.7) (Note 11). The mixture is refluxed for 24 hours (Note 12), cooled, and filtered through a sintered-glass funnel (Note 13) to remove the phosphorus; the flask and the solid are washed with two 20-ml. portions of water. The clear filtrate is transferred to a 300-ml. Claisen flask and concentrated to about 40 ml. by heating in a water bath at a reduced pressure. The residue is washed into a 250-ml. beaker with 70–80 ml. of hot water, and the clear solution is cooled in an ice bath and made strongly alkaline with concentrated ammonium hydroxide (about 80 ml. is required). The next day, the indazole is collected and dried; the white solid melts at 143–145° (Note 14).
The product is added to 75 ml. of benzene, and the suspension is boiled until the frothing has ceased, the benzene lost being replaced (Note 15); the resulting suspension is filtered to remove the insoluble material. The clear filtrate is heated to boiling, diluted with 25 ml. of petroleum ether (b.p. 70–90°), and allowed to cool slowly. The yield of white product, m.p. 145–146.5°, is 9.7–10.2 g. (82–86%). The over-all yield from anthranilic acid is 43–55%.
2. Notes
1. If the starch-iodide test is negative at this point a little solid sodium nitrite may be added.
2. This operation should be carried out in a hood or out-of-doors.
3. Small amounts of a red crystalline solid were obtained at this point by the checkers in several runs. This substance can be converted to o-hydrazinobenzoic acid by the addition of 5 ml. of concentrated hydrochloric acid to a suspension of 1 g. of the solid in 25 ml. of dilute (1:1) hydrochloric acid. The red solid changes to the white o-hydrazinobenzoic acid hydrochloride without apparent solution.
4. The melting point varies with the rate of heating. The values given were obtained with a bath preheated to 180°.
5. The free acid may be obtained by treatment of a solution of the hydrochloride with a concentrated aqueous solution of sodium acetate. The powdered hydrochloride (18.9 g., 0.1 mole) is dissolved in 567 ml. of water, and sodium acetate solution (8.2 g. [0.1 mole] of anhydrous sodium acetate in 30 ml. of water) is added. o-Hydrazinobenzoic acid separates at once; the mixture is chilled, and the light-tan acid is removed by filtration, washed with two 25-ml. portions of water, and air-dried. The yield is 13.1 g. (86%); m.p. 248–250°. If a purer acid is required, the crude material may be recrystallized from ethanol (50 ml. per g.); the pale tan product then melts at 250–251.5°.
6. About 20 g. of sodium carbonate is required.
7. The indazolone may be purified further by recrystallization from methanol (24 ml. per g.), with filtration of the hot solution through a layer of Norit. It separates as white needles, m.p. 250–252°; the recovery is about 50%. An additional 10% of material (m.p. 246–248°) may be obtained by dilution of the filtrate with 2 volumes of water.
The submitter reports that the described method of purification gives a better product than is obtained by solution in dilute sodium hydroxide and reprecipitation with acid.
8. The submitter reports that dimethylaniline can be used but that it is less desirable because a small amount of a green by-product is formed.
9. The crude chloroindazole, m.p. 143–145°, is difficult to dry. Small quantities may be crystallized satisfactorily from water (250 ml. per g.). The submitter reports that a good product can be obtained by steam distillation but that even with superheated steam the distillation is very slow.
10. In a run 2.5 times this size, the checkers dissolved the crude product in 190 ml. of ethanol and diluted the hot filtrate with 260 ml. of water; the chloroindazole was obtained in 80% yield.
11. It is essential to use acid of this concentration.
12. This reaction time ensures complete conversion of the chloroindazole.
13. As an alternative procedure, the mixture may be diluted with 70 ml. of water and filtered through S & S No. 596 filter paper.
14. The crude indazole is so difficult to dry that the weight at this stage is not significant.
15. This operation is carried out in an open flask in the hood and at a point remote from flames; the indazole is dried by the steam distillation of the water with the benzene.
3. Discussion
The preparations of o-hydrazinobenzoic acid hydrochloride and indazolone are essentially those given by Pfannstiel and Janecke.1 The procedure for the conversion of indazolone to indazole is a modification of that of Fischer and Seuffert.2 A procedure involving the decarboxylation of indazole-3-carboxylic acid is described by Schad.3
Indazole has been obtained in a variety of ways which are of no preparative value. The elimination of the amino group from aminoindazoles, first utilized by Witt,4 by the action of ethanol or sodium stannite on the diazonium compounds appears to be the only other useful procedure.
This preparation is referenced from:

tokat - 26-9-2004 at 01:01

m-NITROBENZAZIDE
[Benzoyl azide, m-nitro-]


Submitted by Jon Munch-Petersen1
Checked by William S. Johnson and W. David Wood.
1. Procedure
A. m-Nitrobenzoyl chloride. In a 1-l. round-bottomed flask are placed 200 g. (1.2 moles) of crude m-nitrobenzoic acid2 and 500 g. (300 ml., 4.2 moles) of thionyl choride (Note 1). The flask is fitted (ground-glass joint) with a reflux condenser carrying a calcium chloride drying tube leading to a gas-absorption trap3 and is heated on a steam bath for 3 hours. The condenser is then set for downward distillation, and as much of the excess thionyl chloride as possible is distilled at the temperature of the steam bath. The residue is transferred to a 250-ml. Claisen flask and distilled at reduced pressure (water pump), b.p. 153–154° /12 mm. (Note 2). The yield is 200–217 g. (90–98%), m.p. 33°.
B. m-Nitrobenzazide. In a 2-l. round-bottomed flask fitted with an efficient mechanical stirrer is placed a solution of 78 g. (1.2 moles) of commercial sodium azide in 500 ml. of water (Note 3). The flask is surrounded by a water bath kept at 20–25°. The stirrer is started, and over a period of about 1 hour a solution of 185.5 g. (1 mole) of m-nitrobenzoyl chloride in 300 ml. of acetone (previously dried over anhydrous potassium carbonate) is added from a dropping funnel. m-Nitrobenzazide separates at once as a white precipitate. Stirring is continued for 30 minutes after the addition is complete; then 500 ml. of water is added and the reaction mixture stirred for an additional 30 minutes. The azide is separated on a suction filter, washed with water, and dried in the air. The yield of crude product, m.p. 68°, is 189 g. (98%) (Note 4). It may be recrystallized from a mixture of equal parts of benzene and ligroin (b.p. 100–140°), when the temperature is kept below 50° (Note 5). The product thus obtained consists of almost colorless crystals, m.p. 68–69° (Note 6), the recovery being 80–90% (Note 7).
2. Notes
1. Eastman Kodak Company white label grade thionyl chloride is satisfactory.
2. Since the product crystallizes readily, water cooling should be applied only at the receiver, not at the side arm.
3. The reaction should preferably be carried out in a hood, as hydrazoic acid may be liberated in small amounts. This compound, which is volatile, is highly toxic, and its inhalation may cause temporary headache and giddiness.
4. This product is sufficiently pure for general reagent use. m-Nitrobenzazide is recommended4,5,6,7 as a reagent for the characterization and estimation of aliphatic and aromatic hydroxyl compounds. It reacts to form nicely crystalline m-nitrophenylcarbamic esters,5,6,8 in which the nitro group may be titrated with titanous chloride. With amines it forms substituted m-nitrophenylureas.9,10
5. At higher temperatures a Curtius rearrangement into the isocyanate may occur, nitrogen being liberated. An alternative procedure for recrystallization (preferred by the checkers) consists in dissolving the crude product in a small amount of benzene (if the solution is discolored it may be treated with decolorizing carbon) and adding an equal volume of ligroin. On seeding, the product crystallizes.
6. The melted compound decomposes with liberation of nitrogen.
7. Using the same procedure, p-nitrobenzazide, m.p. 71–72° (Note 6), may be prepared. The yield of crude product is 90%, and of recrystallized product 70%.
3. Discussion
m-Nitrobenzazide has been prepared by the action of nitrous acid on m-nitrobenzhydrazide, which is obtained by treating methyl m-nitrobenzoate with hydrazine hydrate.5,7 The procedure described here is mentioned by Naegeli and Tyabji11 and is similar to that given for benzazide.12

tokat - 26-9-2004 at 01:03

TRIMETHYLSILYL AZIDE
[Silane, azidotrimethyl-]


Submitted by L. Birkofer1 and P. Wegner.
Checked by R. F. Merritt and W. D. Emmons.
1. Procedure
Caution! This reaction should be conducted behind a safety screen in a hood. If the system is not completely dry, the presence of toxic hydrazoic acid is probable.
A 1-l., three-necked flask fitted with a stirrer, reflux condenser equipped with a drying tube, and addition funnel provided with a pressure-equalizer arm is dried in a 100° oven and assembled while warm. The warm apparatus is immediately purged with dry nitrogen, introducing the nitrogen at the top of the addition funnel. The flask is charged with 81 g. (1.2 moles) of sodium azide (Note 1) and 500 ml. of freshly distilled diethylene glycol dimethyl ether (Note 2). A simple distillation apparatus is then dried in the oven and assembled while warm under a slow nitrogen purge. The distillation flask is charged with 112 g. of chlorotrimethylsilane (Note 3), and after a forerun of approximately 2 g. the remaining material is distilled (b.p. 57–58°) directly into the addition funnel of the reaction flask. During this distillation it is convenient to disconnect the nitrogen stream from the top of the addition funnel and introduce it into the distillation flask. After the distillation is complete, the distillation apparatus is disconnected and the nitrogen stream is again introduced at the top of the addition funnel. The chlorotrimethylsilane (108.6 g., 1.000 mole) (Note 4) is then added rapidly to the sodium azide slurry, and this mixture is stirred at 70° for 60 hours. During this period the nitrogen flow is terminated (Note 5).
After the heating period is complete, the nitrogen stream is again initiated, and the mixture is cooled to 30°. The addition funnel and reflux condenser are replaced with two gas-inlet tubes with stopcocks. One inlet tube is connected to the nitrogen source and the other to a standard vacuum trap, of at least 150 ml. capacity. A vacuum (15–20 mm.) is applied to the trap after the latter is cooled to −78°, and the product is then distilled at 30° (15 mm.) into the trap. Slight heating is necessary to maintain 30°, and rapid stirring should be continued throughout. Removal of volatile product is complete within 5 hours under these conditions. The entire system is then slowly pressurized to atmospheric pressure with nitrogen, and the product is redistilled through a 5-cm. Vigreux column. From 121 g. of crude flash distillate are obtained 4.0 g. of forerun and 98 g. (85%) of pure trimethylsilyl azide, b.p. 95–99°. During the distillation the pot temperature is maintained at 135–140° with a thermostated oil bath. The pot residue contains 19 g. of diethylene glycol dimethyl ether with traces of trimethylsilyl azide. The purity of the product cut as established by 1H NMR (CCl4) is 98%. A single peak at 13 cps. downfield from tetramethylsilane is observed, the only impurity being siloxane hydrolysis products. Chlorotrimethylsilane is conspicuous by its absence.
2. Notes
1. Sodium azide was obtained from Alpha Inorganics, Inc., Beverly, Massachusetts, and the freshly opened material was used without further purification or drying.
2. Diethylene glycol dimethyl ether from Aldrich Chemical Co. was distilled under a nitrogen atmosphere, and the fraction boiling at 161–162° was used.
3. The chlorotrimethylsilane was obtained from Pennisula Chem-research Corp., Gainesville, Florida.
4. It is undesirable to reweigh the chlorotrimethylsilane in the addition funnel because moisture contamination is possible. An excess of sodium azide is used in this preparation, and the exact amount of the silane used is not critical.
5. If the nitrogen flow is maintained during the heating period, the volatile materials will be swept out and the yield will be reduced.
3. Discussion
Trimethylsilyl azide has been prepared by the thermolysis of 1-trimethylsilyl-5-trimethylsilylaminotetrazole, by reaction of hydrazoic acid with hexamethyl-disilazane, and by reaction of chlorotrimethylsilane with sodium azide.2 With a suitable solvent and anhydrous conditions the last procedure is the method of choice and has been extended to other trialkyl and triarylsilyl azides.3
Unlike hydrazoic acid, trimethylsilyl azide is thermally quite stable. Even at 200° it decomposes slowly and without explosive violence. Accordingly, it is a very convenient and safe substitute for hydrazoic acid in many reactions. A notable example is the cycloaddition of hydrazoic acid to acetylenes, a general route to substituted triazoles.4 The reaction of trimethylsilyl azide with acetylenes is also a general reaction, from which 2-trimethylsilyl-1,2,3-triazoles may be obtained in good yield.5 These adducts are hydrolyzed under mild conditions to the parent alkyl 1,2,3-triazoles.5

Another interesting application of trimethylsilyl azide is as a convenient preparation of trialkyl- or triarylphosphinimines, first prepared by Appel and Hauss using chloramine.6

This synthesis is quite simple and its success lies in the facile cleavage of the Si-N bond.7,8 Trimethylsilyl azide also reacts with aldehydes, giving the stable adducts, 1-trimethylsiloxyalkyl azides, which on thermolysis yield N-trimethylsilyl amides.9

This preparation is referenced from:

tokat - 26-9-2004 at 01:04

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.

Nitramine - 4-10-2004 at 12:25

Quote:
Nitramine,

Did you ever find an archive copy of the webpage detailing extraction of NaN3 from airbag pellets?

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

sylla - 4-10-2004 at 12:30

nice spam tokat but it would have been a better idea to write it in a txt and send it as an attachment...

Don't u think ?

3 types...

DNA - 26-11-2004 at 16:51

What about the 3 different types of lead azide?
Could you tell a bit more about that?

JohnWW - 27-11-2004 at 00:53

I am sure there can be only ONE type of Pb(N3)2, which is that used in detonators. Perhaps you were thinking of other azide compounds, e.g. Pb(N3)4 (very unstable if it could be made!), or PbO(N3)2, or PbClN3.

neutrino - 27-11-2004 at 09:01

I thik he might be referring to something along these lines: Pb(N<sub>3</sub>;)<sub>2</sub>, PbOHN<sub>3</sub> (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]

The_Davster - 27-11-2004 at 10:13

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.

La1.JPG - 116kB

The_Davster - 27-11-2004 at 10:15

page 2

LA2.JPG - 160kB

The_Davster - 27-11-2004 at 10:17

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.

LA3.JPG - 186kB

OTC azide?

The_Davster - 7-2-2005 at 20:04

I was reading Ullmann's yesterday, and it mentioned that barium azide is used "in fluorescent light tubes to improve the light yield."

This could be a viable source for azide depending upon how much barium azide is used in a fluorescent tube. Of course, removing the azide would be quite dangerous as when the glass is broken barium azide would be spread into the air, as it is most likely used as a fine powder coating.

Copper (II) Azide

chemoleo - 12-4-2005 at 17:35

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 (:o), and immediate washing with ethanol and then ether.

[Edited on 13-4-2005 by chemoleo]

Oh dear...

The_Davster - 12-4-2005 at 18:43

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.

CA1.JPG - 102kB

The_Davster - 12-4-2005 at 18:46

page 2

CA2.JPG - 126kB

The_Davster - 12-4-2005 at 18:48

page 3

CA3.JPG - 135kB

Lambda - 16-4-2005 at 13:25

Quote:
Originally posted by heksogen
I know that lead azide is made by mixing solutions of lead nitrate, sodium azide and dextrin and sodium azide is made by bubling nitrogen oxide throw molten sodium amide. My question is :
Are there any other ways to get sodium or hydrogen azide???

Preperation of Azides

Lambda - 16-4-2005 at 13:36

Please install eMule 0.45b and search for "BRAUER" Handbook of preperative inorganic chemistry vol. 1-2. In this work of art, you will find the synthesis of Azides, and many more inorganic explosive substances.

halogen - 16-4-2005 at 14:43

Pardon me, if I have asked before, however; Could dilute hydrazoic acid or ammonium azide not be formed by bubbling N2O through warm ammonia solution, by the reaction
NH3 + N2O --> H2O + HN3
?

[Edited on 16-4-2005 by halogen]

Lambda - 16-4-2005 at 15:00

You will grow a very long beard in the process, no insult intended. Please check out how molten Na (a violent reductor) reacts with NH3 to form NaNH2 (amide), with the evolution of H2 gas, and you will see why. N2O is relatively inert, and will find itself in an uphill battle with NH3 in respect to plucking of a hydrogen atom.
Molten NaNH2 however, gives a different story.
[Edited on 17-4-2005 by Lambda]

[Edited on 17-4-2005 by Lambda]

S.C. Wack - 16-4-2005 at 15:19

This one doesn't use sodamide or nitrites, so I put it here regardless of what it does use - NCl3. It is Ber. 32, 1399 (1899)

Diese Säure entsteht bei der Einwirkung des Chlorstickstoffs auf
Hydrazin. Seitdem Hentschel gezeigt hat, dass man eine Benzollösung
des Chlorstickstoffs gefahrlos herstellen und handhaben kann,
wird wahrscheinlich diese bisher gefährliche und gern vermiedene
Verbindung in den Kreis der gebräuchlichen Reagentien treten.
Ich nehme dreimal mehr Benzol, als Hentschel vorschreibt und bekomme
also eine 3.3-procentige Lösung von Chlorstickstoff. 30 ccm
dieser Lösung habe ich mit der kalten wässrigen Lösung von 1.5 g
Hydrazinsulfat im Scheidetrichter unter öfterem Schütteln zwei Stunden
zusammenwirken lassen. Hierauf habe ich die wässrige Lösung mit
Natronlauge genau neutralisirt, 10 ccm normaler Schwefelsäure zugesetzt
und ein Viertel der Flüssigkeit abdestillirt. Das saure Destillat
giebt mit Silbernitrat sofort einen weissen Niederschlag, der in Salpetersäure
sich vollständig löst. Bin Körnchen des trocknen Salzes
explodirt beim Erhitzen sehr heftig. Zweifellos ist es Stickstoffsilber,
AgN3. Die Ausbeute ist aber nur klein: ich habe in zwei Versuchen
5 pCt. und 6.5 pCt. der theoretischen Menge an Stickstoffwasserstoffsäure
erhalten. Im zweiten Versuch habe ich nach der
Reaction die Benzollösung mit 20 ccm Wasser gewaschen; vielleicht
ist es diesem Umstande zuzuschreiben, dass dabei die Ausbeute etwas
grösser ausfiel. In der Benzollösung bleibt noch viel unveränderter Chlorstickstoff.

Bessere Resultate lassen sich erzielen bei der Einwirkung von
Chlorstickstoff auf freies Hydrazin. Ich verfahre wie oben beschrieben,
nur mit dem Unterschiede, dass ich von Zeit zu Zeit 10-procentige
Natronlauge in kleinen Portionen (3—5 ccm) in den Scheidetrichter
gebe, bis die wässrige Lösung dauernd stark alkalisch reagirt. Im
Ganzen werden 30—35 ccm Lauge verbraucht. Die Operation dauert
unter öfterem Umschütteln 1 1/2 Stunden. Die wässrige Lösung
wird jetzt mit Schwefelsäure neutralisirt und nach Zusatz von 10 ccm
normaler Schwefelsäure ein Viertel der Flüssigkeit abdestillirt. Das
Destillat enthielt ein Mal keine Salzsäure, ein anderes Mal nur Spuren
davon. Acidimetrisch und dem Gewicht des Silbersalzes nach wurde
bestimmt, dass die Ausbeute an Stickstoffwasserstoffsäure 36 pCt. der
theoretischen erreichte, auf 1 g Chlorsticketoff gerechnet. Aus der
titrirten Säure bekam ich das Silbersalz und bestimmte darin das
Silber; gefunden wurden 71.13 — 71.03 pCt. Silber, während Silbernitrid
71.92 pCt. Silber enthalten soll.

Da bei der Einwirkung von Chlorstickstoff auf Hydrazin Gase
(Stickstoff?) und andere Nebenproducte nicht in auffallender Menge
entstehen, so glaube ich, dass die Ausbeuten an Stickstoffwasserstoffsäure
beim Arbeiten in grösserem Maassstabe höher ausfallen werden
und dass die beschriebene Darstellungsweise dieser höchst interessanten
Säure in manchen Fällen gebraucht werden kann. Bei der
Einwirkung von Kaliumnitrit (Angelo Angeli) und von Salpetersaure
(Sabanejeff) auf Hydrazinsalze entstehen nur kleine Mengen der
Stickstoffwasserstoffsäure, nur die Methode von Wislicenus giebt bessere Resultate.

The_Davster - 16-4-2005 at 15:26

I am interested in such a novel route, however my level of German courses is not high enough for me to understand the majority of that. Could you post a translation?

EDIT: I used a online translator and got the gist of it, but a potentially serious number of nonsense phrases and untranslated words resulted.

[Edited on 16-4-2005 by rogue chemist]

Translation

Lambda - 16-4-2005 at 16:13

I will translate this preperation, and get it up and running on monday.

redneck - 16-4-2005 at 22:55

Hey S.C.WACK you live in the states, so where did get such an old german chemistry boock? Do you speak german?


Translation:

This acid develops during the effect of the nitrogen trichloride on hydrazine. Since Hentschel showed that one can manufacture and handle a benzene solution of the nitrogen trichloride safely, this dangerous and gladly avoided compound will probably step into the circle of the common reagents. I take three times more benzene, than Hentschel prescribes and get thus a 3.3-percentage solution of nitrogen trichloride. I let 30 ml of this solution react with the cold aqueous solution of 1.5 g hydrazine sulfate in the separating funnel under frequent shaking for two hours. Then I exactly neutralised the aqueous solution with a caustic soda solution, afterwards I added 10 ml of normal sulfuric acid and distilled over a quarter of the liquid. The sour distillate immediately forms with silver nitrate a white precipitation, which solves completely in nitric acid. One grain of the dry salt explodes very violently if heated. It surely is silver azide, AgN3. The yield is however only small: I received in two attempts 5 % and 6,5 % of the theoretical amount of hydrazoic acid. In the second attempt I washed the benzene solution after the reaction with 20 ml water; perhaps it is to be attributed to this circumstance that thereby the yield was somewhat bigger. In the benzene solution remains a lot of unchanged nitrogen trichloride.

Better results can be obtained by the reaction of nitrogen trichloride with free hydrazine. I proceed like above described, only with that differences that I give a 10% sodium hydroxide solution in small portions (3-5 ml) occasionally to the
separating funnel, until the aqueous solution reacts continuously strongly alkalinely. In the whole one 30-35 ml caustic solution is used. The operation lasts 1 1/2 hours under frequent shaking. Now the aqueous solution is neutralised with sulfuric acid and after the addition of 10 ml of normal sulfuric acid a quarter of the liquid is destilled over. One time
the distillate did not contain hydrochloric acid, another time only traces of it. Acidimetric (?titration?) and by the weight of the silver salt was determined that the yield of hydrazoic acid reached 36 % of the theoretical, calculated to 1 g nitrogen
trichloride. From the titrated acid I got the silver salt and determined therein the silver; 71,13-71,03% silver was found,
while silver nitrite is said to contain 71,92% silver.
Because during the reaction of nitrogen trichloride with hydrazine, gases (nitrogen?) and other byproducts are not formed in remarkable quantities, I believe that the yields of hydrazoic acid will be higher when working with larger batches and that the described synthesis of this very interesting acid can be used in some cases. During the reaction of potassium
nitrite (Angelo Angeli) or of nitric acid (Sabanejeff) with hydrazine salts form only small quantities of the hydrazoic
acid, only the method of Wislicenus gives better results.

The_Davster - 16-4-2005 at 23:14

THANK YOU
:):cool:

The Hodgkinson Azide Patents

Rosco Bodine - 16-4-2005 at 23:33

There have been many experiments done by me trying to replicate the reactions of the Hodgkinson patents ,
with no success .
It is my opinion that the reaction mechanism simply does not work as described in these patents .
However here they are as attached files for anyone else who may wish to try their luck .

Thanks to franklin for image cleanup and editing
of the pdf's for these two old microfiche patent images .

GB128014 attached


[Edited on 5-1-2008 by Rosco Bodine]

Attachment: Azide from N2H4 + NaNO2 - GB128014.pdf (693kB)
This file has been downloaded 1676 times


GB129152

Rosco Bodine - 17-4-2005 at 08:16

GB129152 ( attached file )

Thanks to franklin for cleanup and image editing of this
old microfiche image file .

[Edited on 5-1-2008 by Rosco Bodine]

Attachment: AgN3 - GB129152.pdf (652kB)
This file has been downloaded 2236 times


S.C. Wack - 17-4-2005 at 14:23

Pre 1902 Ber. is found at Gallica, I can write and pronounce German with confidence because it is/was suggested to amerikan chemistry students to take German - but since I have little need to ask where the train station is, what little that I learned in German 1 is useless. I say "schade" sometimes.

These are the Hentschel refs for NCl3 from the above (otherwise complete) article and Inorganic Syntheses: Ber. 30, 1792-5 and 2642 (1897).

Attachment: hentschel_ncl3.pdf (273kB)
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Rosco Bodine - 17-4-2005 at 16:58

Quote:
Originally posted by halogen
Pardon me, if I have asked before, however; Could dilute hydrazoic acid or ammonium azide not be formed by bubbling N2O through warm ammonia solution, by the reaction
NH3 + N2O --> H2O + HN3
?

[Edited on 16-4-2005 by halogen]


See US3012851 for a description of the
reaction and conditions which do work .

probably as easy as it gets

S.C. Wack - 18-4-2005 at 21:48

JACS 27, 551 (1905):

Attachment: azides_from_h2o2_and_hydrazine_sulfate.pdf (607kB)
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interesting method has potential ....

Rosco Bodine - 19-4-2005 at 13:55

However , it sure does involve a lot of handling of bulky dilute solutions , from which is derived a pretty small yield relative to the volume of the reactants which must be distilled .

Studying the method , it looks like there is the potential there for working with more concentrated solutions and perhaps increasing the yield to a point where the synthesis would have more value .

Just looking at the charted experiments ,
it seemed to be an interrupted logical progression not to next try 1 gram of hydrazine sulfate per ~20 ml of 3% H2O2 with 5-10 ml conc. H2SO4 and no H2O .
Then to do a series of followup experiments to examine the reaction under more concentrated conditions ,
in order to discover the optimum economy
for a reasonable reaction mixture volume at which is produced practical yields .

I have a feeling that a good yield might be possible adapting the reaction to be performed in a mixture of 27% H2O2 and
electrolyte grade 1.260 d , ( 35% ) , 4.5 molarity H2SO4 , with some amount of dilution H2O added if necessary .

If the reaction would proceed with as good or better ,
( or at worst not too much reduced yield ) at double or triple the
concentration of the reaction mixture ,
then it would be more practical , for not requiring many liters of distillate to obtain a very few grams of azide .

When I experiment with this method , I will likely discharge the distillate directly
into an alkaline solution , such as perhaps
a cold stirred aqueous suspension of excess Ca(OH)2 ,
producing highly soluble Ca(N3)2 .
When the distillation
is complete to a rising boiling point indication , the solution in the receiver
will be heated to almost boiling and filtered hot to remove unreacted
Ca(OH)2 , taking advantage of its greatly reduced solubility in hot solution . Upon
concentration and evaporation of the filtrate should be obtained crystals of the
trihydrate of calcium azide in relatively pure condition . This could be used in the same way as sodium azide is used in most
syntheses .

Or sodium azide could be obtained by conducting the distillate into a sodium hydroxide or sodium bicarbonate solution ,
slightly less than the amount of theory needed for neutralization of the HN3 to
be distilled , and continuing the introduction of distillate until the solution
indicates a slight acidity . Concentration and evaporation of the solution would give pure sodium azide .

Actually this production of the sodium azide could be done first , using quantities
of alkali certain to be neutralized by the
expected yield of HN3 in the first three quarters of the distillate . And when the
solution of sodium azide is complete and
it begins to acidify with free HN3 from the remaining distillate , then the remaining distillate could be discharged into the cold limewater to safely absorb the remaining HN3 still coming over , and provide a method of its recovery in usable form .

A source of Barium Azide

Lambda - 19-4-2005 at 14:22

OTC AZIDES ? Originaly posted by Rogue Chemist on 8-2-2005

Barium azide is used in fluorecent tubes as a frequency converter. The original source being ultraviolet radiation caused by ionized "MERCURY VAPOUR". These TL tubes are often coated by mixtures of flourecent salts, and depending on the manufacturer have a specific color code and composition. The pop that you hear when rupturing a TL tube is an implosion. The real hazard involving tube rupture is the mercury vapour, and an implosion often tends to give larger chunks of flying glass as would be expected with an explosion. Wounds caused by this stuff can be slow healing and cause intoxication.

neutrino - 19-4-2005 at 15:12

Distilling HN<sub>3</sub>? I would certainly stay away from that, as the gas is extremely poisonous (much more so than HCN).

Rosco Bodine - 19-4-2005 at 15:30

But I bet you would work with nitrations routinely where nitric oxide is but little less deadly .

When you do such a distillation , it is easily done as a closed but vented system process . Most of the HN3 will
likely come over in the early part of the distillation and in diluted aqueous form
through a cold condenser , being discharged directly into a neutralizer which
ties up the material as a nonvolatile salt ,
while any unreacted fumes are vented away through a length of tubing and discharged into the air at a distance or
aspirated down the drain in a water stream . It's really quite simple to set up
the apparatus to do this safely .

But in chemistry it is sort of like driving a car , careless mistakes can kill you , and so can not knowing what you are doing ,
or just plain bad luck , and not necessarily
in that order .

neutrino - 19-4-2005 at 15:49

I didn't know that those were on par with each other. Well, I've never done a nitration (Oh, the shame!)

BromicAcid - 19-4-2005 at 15:52

I was under the impression (that may well be wrong) that distilling HN3 was significantly more dangerous then distilling hydrazine. E.g., it could explode from light, dust in the distillation apparatus, from becoming too concentrated, from local hot spots, etc. I have a certain affinity for acids and if I believed HN3 could be stored and made relatively safely I would likely stockpile it.

Rosco Bodine - 19-4-2005 at 16:06

Quote:
Originally posted by BromicAcid
I was under the impression (that may well be wrong) that distilling HN3 was significantly more dangerous then distilling hydrazine.

You were impressed correctly in that much .
Quote:
E.g., it could explode from light, dust in the distillation apparatus, from becoming too concentrated, from local hot spots, etc. I have a certain affinity for acids and if I believed HN3 could be stored and made relatively safely I would likely stockpile it.


" from becoming too concentrated " are the words of essential importance there .

Extremely essential , definitively important actually .

Concentration is everything about the
safety or suicidal nature of handling HN3 ,
particularly during distillation .

BromicAcid - 19-4-2005 at 16:19

So, about the 'too concentrated' aspect, does hydrazoic acid have an azeotrope with water? Searching for "Hydrazoic acid azeotrope" on google gave 14 hits, none of them relevent. What I did find for the pure substance is from my chemistry encyclopedia:
Quote:
Hydrazoic acid (hydrogen azide)
CAS: 7782-79-8. HN3
Properties: Colorless, volatile liquid; obnoxious odor. Fp -80C, bp 37C. Soluble in water.
I also remember reading somewhere, likely on this site of the ability of HN3 to attack the DNA of an individual and cause a multitude of problems as a result of this. However even if there is an azeotrope steam distillation would help prevent the distillation of a concentrated product.

[Edited on 4/20/2005 by BromicAcid]

Rosco Bodine - 19-4-2005 at 16:25

Check the usual trustworthy references
and you'll find that dilute HN3 can be distilled safely at ordinary pressure .
COPAE , PATR , Urbanski , ect .

Offhand I forget the percentage that is
safe , below 10% I think , but I would double check some references to make certain .

UPDATE : Below 10% HN3 is reportedly the safe range for aqueous solutions for storage and handling considerations .
However , it is not safe to subject even these dilute solutions to plain distillation
conditions .

Steam distillation methods or other vapor entrainment methods are good practice .

Special techniques * must * be used for distillation , so that the reaction producing
the HN3 occurs only gradually in an
* already boiling * aqueous mixture , so that the HN3 produced is in small percentage with regards to the steam already evolving , the steam carrying with it the safe small percentage of HN3 vapor as a minor proportion .

An aqueous system already containing HN3 should not be reheated or distilled because the volatile HN3 will evolve from it as concentrated vapor which has high probability of explosion . The HN3 can
be stripped from an aqueous solution as it is warmed slowly by gas entrainment .
Again as in the case of mixture with water vapor , the percentage of HN3 in the entraining gas stream of air , nitrogen , or hydrogen should be less than 10% HN3 vapor .

Following these special techniques , a modification of the method of Browne should be tried for the sake of safety .

The hydrazine sulfate and sulfuric acid solution should be already boiling freely
as the hydrogen peroxide is added dropwise , and in this way the HN3 produced would be carried away on the steam as quickly as it forms , preventing any substantial concentration buildup of HN3 vapors in the apparatus .

Alternately , a steady stream of air could be supplied to a dispersion tube in the solution in the distilling flask , so that any
HN3 evolved as the reaction mixture is warmed will be diluted in the airstream and carried into the receiver . By this method a concentration of HN3 vapors
will be prevented accumulating above the warm solution , before the time when it is boiling and the steam would then accomplish the entrainment . Given the volatility of the HN3 , air entrainment would likely strip nearly all the HN3 from the solution well before the boiling point ,
and physical distillation of the entire
reaction mass would not even be necessary .


[Edited on 20-4-2005 by Rosco Bodine]

S.C. Wack - 19-4-2005 at 21:08

Browne went on to write many other articles in JACS on the subject of hydrazine and hydrazoic acid over the years. This is what I could find that had preparative value - I scanned 3 fragments of two articles. In JACS 31, 221 (1909) the hydrazine sulfate is oxidized with:

persulfate in acid and alkali
KMnO4 in acid and alkali
H2O2 in acid and alkali
perchlorate, PbO2, periodate, and MnO2 in acid.

He revises the yields in the earlier article here. Many other things were tried in other articles, and only the persulfate and H2O2 in H2SO4 are included from this article. The perchlorate had lower yields and the others not included much lower. Later on in that volume on page 798 he states that he has never made any attempt to increase the yield in the H2O2 by fine-tuning. Even though he states in several places that he has done this many times and in larger amounts than published.

In the next article snippet he is doing more experiments with H2O2/H2SO4, comparing the yields to nitrite/H2SO4. HNO2 wins.

Attachment: azides_by_oxidation_part2.pdf (394kB)
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Rosco Bodine - 20-4-2005 at 07:14

The weight of product from these reactions which oxidize 2 moles of hydrazine to produce only 1 mole of hydrazoic acid , can never match the
weight of product obtained from the
more efficient nitrosation reactions which
operate according to a different equation
where each 1 mole of hydrazine may be
condensed with the nitrosation reagent to
produce 1 mole of hydrazoic acid .

Since the hydrazine is already difficult enough to make and involves handling of fairly voluminous solutions , it is not appealing to pursue a similarly laborious
manipulation of voluminous solutions for
a reaction which will at the very least destroy fully half of the hydrazine present , without any conversion of that
hydrazine to the desired hydrazoic acid ,
even if the " oxidation " reaction were to proceed at 100% efficiency , which it certainly does not . Typically , three quarters of the laboriously made hydrazine is destroyed in this reaction scheme , which at best converts ~25% of
the hydrazine to hydrazoic acid . So this
reaction may have academic interest , but
is too inefficient for any practical purpose
due to the poor economics of the method .

Compare the yield on a mole per mole basis from hydrazine sulfate to sodium azide typically in the range of 65 to 85%
for the scenario where the hydrazine is
freebased into isopropanol and the basified solution treated with isopropyl nitrite or nitrosated with the N2O3 from
decomposition of HNO3 warmed with starch , the NaN3 crystallizing out directly
in pure form from a small volume reaction mixture , easily filtered . This is a much
more economical and safer , more efficient
reaction route than any alternatives which
I have seen reported as practical lab methods for preparation of NaN3 in good
yield and purity .

There is another article by Browne
( and Wilcox ) which relates to the more efficient route . Since you have access to these citations please post them here .

Browne & Wilcox , JACS 48 , 682 ( 1926 )

E.C. Franklin , JACS 46 , 2137 ( 1924 )

J.W. Turrentine , JACS 34 , 385 ( 1912 )

Dennstedt & Gohlich , JCS 74 II , 425-6
( 1898 )

[Edited on 20-4-2005 by Rosco Bodine]

Axt - 20-4-2005 at 10:00

How amazingly simple. How come such a simple method for arguably the most important primary has not been brought up before. I tried to adapt it to the most simple way possible;

I just mixed 16g potassium persulphate, 4g hydrazine sulphate in 100ml water. Added 50ml sulphuric acid. The heat created by the acid addition boiled off, and the resultant gas was bubbled through a dilute lead acetate solution. Result was a precipitate of Pb azide!, yield was dismal, but it certainly works, safety may be questionable but it is as simple as stated. <a href="http://ww1.altlist.com/~62552/xmovies.altlist.com/banners/xmovies.html">MOVIE</a> of ignition of ~1/4 matchhead Pb azide.

Replacing persulphate with H2O2 seemed to resulted in the same thing, though I made no attempt to "catch" it as Pb azide.

Rosco Bodine - 20-4-2005 at 10:14

Indeed these destructive oxidation of hydrazine reactions are simple and interesting for that reason alone , even if the methods are low yield and inefficient .

I wonder what the possibility is of using a percarbonate , or a perborate in similar fashion .

Oxy-Clean contains which of these I don't recall , but is sold virtually everywhere ,
along with the various other non-chlorine
substitute bleach products , based on various peroxy compounds .

Axt : You realize that producing the concentrated HN3 vapor is extremely dangerous , that the slightest pressure change , as occurs from even bubbles
discharging from a bleed tube can set the vapor off , and so can sunlight , perhaps
even the sound from clapped hands , or
snapped fingers , perhaps even a fart .....
kaboom ! You don't want to even look at this stuff in accumulated form if it is avoidable . I wonder if doing such a procedure in a PET pop bottle would be a good idea , if the poly is compatable with short term exposure to the HN3 vapor , because when the vapor does detonate as it sooner or later likely will ,
there wont be any glass shrapnel from
the event , just pieces of plastic soda bottle .

When you used H2O2 , what strength did you use ?

[Edited on 20-4-2005 by Rosco Bodine]

Axt - 20-4-2005 at 10:57

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]

Rosco Bodine - 20-4-2005 at 11:10

Quote:
Originally posted by Axt
I did use a long PVC tube to carry the gas to the Pb acetate solution.


transparent det cord ;)

Axt - 20-4-2005 at 12:27

Quote:
Originally posted by Rosco Bodine
transparent det cord ;)


Yeh. But you do at least have to monitor the precipitating solution, as to prevent it getting drawn back as the reaction vessel cools.

[Edited on 20-4-2005 by Axt]

Rosco Bodine - 20-4-2005 at 12:59

You know really the best setup would be
to put a dip tube into the reaction flask and use an aquarium pump to create a small steady stream of air to carry the HN3 fumes through to the second dip tube
and bubbler , air stone or dispersion frit in the receiver .

Alternately you could use an aspirator to pull a slight vacuum over the liquid in the receiver and simply vent air into the dip tube in the reaction flask , allowing the aspirator to pull some air continuously
through the liquids in both the reaction flask and the receiver . Either setup would effectively dilute the vapor and
also would strip the last traces of HN3 from the reaction mixture and connecting tube .

chemoleo - 20-4-2005 at 13:04

Not to kill your enthusiasm or something, but I don't see why this method is so much preferable. Yields are low. Dangers are potentially quite high.
While making isopropylnitrite is not particularly difficult/hazardous, nor difficult to obtain if one is able to obtain hydrazine(sulphate) in the first place.

Don't you think the bottleneck of azide production is still the synthesis of hydrazin? Having made it via the Raschig method, and the crappy yield (which is the bottleneck), I'd rather make some additional isopropylnitrite than mess about with peroxides, HN3 gas with explosion/toxic hazard. Oh well. Just my thoughts on the matter.

Still it's interesting that HN3 can be obtained so easily, by simple oxidation.

Rosco Bodine - 20-4-2005 at 14:58

Agreed that hydrazine sulfate is the greatest difficulty about the entire process . But in my absolutely unbiased opinion :D , 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 .

Axt - 20-4-2005 at 15:18

While I somewhat disagree on the hydrazine sulphate issue (hard to get good yield BUT easy to get a low one, with common reagents).

What is the oxidation product of urea/persulphate if any? the ability to replace hydrazine suphate with urea would be ... interesting.

[Edited on 20-4-2005 by Axt]

chemoleo - 20-4-2005 at 15:40

Hehe, Axt and his (in?)famous one pot syntheses!
If you get that to work, you get the MS award of the year :D
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 :o

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

Rosco Bodine - 20-4-2005 at 17:15

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 :D

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]

S.C. Wack - 20-4-2005 at 22:34

In the last series of experiments in the last pdf the apparatus used is not described as I didn't copy that part - this is the missing description:

The apparatus employed in the experiments consisted of a liter distilling flask provided with a two-hole rubber stopper, through which passed the stem of a dropping funnel and a tube for the admission of a current of air. To the side arm of this flask was sealed a Reitmeier bulb, through which communication was established with a condenser. The receiver consisted of two 250 cc. Erlenmeyer flasks in series. The flask nearer to the condenser was connected to it by means of an adapter and contained at the outset 25 cc. of water, below the surface, of which dipped the lower end of the adapter. The second Erlenmeyer flask contained at the outset 10 cc. of water, into which dipped the end of the tube through which connection was established with the first flask.

I'm not sure why I should be freaked out about the HN3 exploding when the distillate is aqueous. Certainly in the many articles there was no mention of explosions. Chem. Rev. 15, 169 (1934) says that if a HN3 solution is distilled, a small quantity of HN3 comes over a gas, followed by a 27% solution, and the rest distills as a constant-boiling mixture containing very little HN3. It gives no ref for this but a classic available article would be this long J. prakt. article which begins on page 261.

I mentioned a few nitrite patents earlier. There is also Inorganic Syntheses. Obviously it is no trouble to make an alkyl nitrite if one so desires, so this is not about max yields. If one has byproduct ethyl nitrite, well then this would be a good use for it.
Stolle's patent

The citations mentioned earlier: The 1926 one is a sodamide article, and I don't really see sodamide or liquid ammonia and alkali metal being put to use in this way in the future of any members here. The 1924 one is a review of the general reactions of inorganic amides. The JCS one is an abstract where 3.3 g KNO2 is dissolved in 200 ml water, some H2SO4 is added, and this is cooled. Then a cold solution containing 5 g. hydrazine sulfate was added and after O, N, and N2O evolution ceased, this was distilled and the distillate contained 200 mg. HN3. And I forgot the remaining 1912 article, I'll look it up later.

PS - It was a brief note mentioning structure but not really saying anything about anything.

[Edited on 22-4-2005 by S.C. Wack]

Rosco Bodine - 21-4-2005 at 05:25

The method of Stolle would work with any
organic nitrite . Isopropyl nitrite has become the preferred organic nitrite simply because the alcohol from which it derives is cheaply and readily available ,
and the nitrite ester made from it has lower volatility than ethyl nitrite , making it much easier to use as a nitrosation reagent .

The earlier citations were listed in PATR as
being related to the reactions of nitrous acid and hydrazine . Another PATR misprint revealed , and there are a few of them .

The hazards of HN3 were reported in the early work by Curtius , I am pretty sure .
The hazard was reported particularly for
concentrated solutions , and also for concentrated vapors , and there were
explosions and even a couple of fatalities
reported .

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

Hydrazine preparation

chemoleo - 1-5-2005 at 07:57

The extremely detailed synthesis instructions/experimentals have now been moved to the dedicated hydrazine thread.
Please continue the discussion there.

garage chemist - 6-5-2005 at 06:32

(This is about azides again, so I'm posting it here. I'm referring to my procedure from the hydrazine thread.)

My precipitate is definately sodium azide, because it deflagrates violently when heated in a test tube (it takes a lot of heat to initiate it, but then it deflagrates faster than black powder). It doesn't melt though.
The strange part is that it leaves a BLACK residue (apart from the white sodium oxide smoke) which doesn't dissolve in water!
I assume this is an organic impurity from the denatured ethanol. It is denatured with ketones (and bitrex), and ketones react with hydrazine to form ketazines, which have a high boiling point. The crystallizing NaN3 probably carried some of these with it.
This is bad! I need to carry out the diazotation reaction another time with "renatured" ethanol. This will take some time to make (refluxing the ethanol with NaOH for half a day).

The denatured ethanol also seems to contain a stinking "oil" with a high boiling point. Even simple distillation probably helps a bit.

A list of denaturants for german Brennspiritus would be of great help. If anyone knows such a site, please let me know!

[Edited on 6-5-2005 by garage chemist]

Taaie-Neuskoek - 6-5-2005 at 06:49

Quote:

A list of denaturants for german Brennspiritus would be of great help. If anyone knows such a site, please let me know!

You can always ask the company for an MSDS, they should specify what's in there. I've done that some times for products, and they always send the stuff right away per email.
It can be that they say: Between 75 and 95% ethanol, and between 5 and 25% methanol, the data is most of times everything but accurate...

garage chemist - 6-5-2005 at 10:41

I was able to clean my NaN3 by repeated stirring with acetone and then decanting. Ketazines are soluble in ketones (but apparently not in ethanol).
Now it deflagrates cleanly and only leaves some sodium globules which rapidly turn into the oxide. No black residue any more.

It weighs only 3,3g though... that's a 51% yield (from hydrazine sulphate).
I need to run the reaction in a more concentrated solution.

Right now I'm refluxing 350ml Spiritus with NaOH.

I found a list with common denaturants. Ketones dominated the list. Other than those, also listed were turpentine (not present in my ethanol, as a distillation showed), gasoline (wouldn't disturb the reaction) and pyridine. Pyridine could be easily removed by distillation with a small amount of sulfuric acid. I'll do this if the NaOH doesn't remove the "denaturant" smell.
But would it be necessary to remove the pyridine? Does pyridine give any reaction with hydrazine, NaOH, IPN or azides?

Rosco Bodine - 6-5-2005 at 13:03

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

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]

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