NaN3 From Airbag

[Anthony]

Here's a rough guide I knocked up whilst theforum was down, about my experience of retrieving the sodium azide from an airbag unit:

<a href="http://www.geocities.com/eawfuk/sodium_azide_from_airbag.htm" target="_blank">http://www.geocities.com/eawfuk/sodium_azide_from_airbag.htm</a>

All comments/corrections welcome.

Hopefully the pictures will load, Word2k is playing silly buggers about generating a HTML document, stupid piece of crap. I would have done the whole thing as a thread here but couldn't imbed the pics.

BTW, I just sucked a teabag. It could do with some sugar and a bit of milk.

[Polverone]

Sorry, MS Word betrayed you. The pictures don't show up, and the guide is really diminished by their absence.It seems like a nice guide in general. This could be quite handy for people unwilling/unable to order/synthesize NaN3 - depending, of course, on the availability and cost of the units. How'd you obtain the airbag unit, and what (if anything) did it cost you?

If you're going to make lead azide then you could extract the azide from the airbag pellets shortly before the reaction and just use the solution, right? Because the other components are insoluble but so's the lead azide you're hoping to make. Distilled water with a small amount of NaOH added to it would probably be able to safely dissolve the NaN3 without releasing HN3. But that's just speculation on my part.

[Anthony]

POS...

I h4x0red lumps out of word's silly code and replaced them with a simple img tag and Bob's your uncle. Honestly, 50-75% of the document is unneccesary shite that word has put in to support it's own sillyness. Stupid Micro$oft, Notepad is about the only decent program they've ever made!

Right, I'm off to make a fry-up and watch the sun rise while I'm at it, yummykins :)

[cutefix]

Wait ,It appears okay in my PC!However it took some time to completely download the picture .

Its interesting site Anthony!
As there are many uses of sodium azide in the synthesis of other explosives aside from lead azide as long it can be recovered in pure form.

[mr.evil]

Hello,
well..that's ALOT of NaN3!! i think i go look at the car recycle plant :) (or whatever that is called in english)

<img src="http://www.geocities.com/eawfuk/airbag1.jpg" alt="" />
#1

<a href="http://www.geocities.com/eawfuk/airbag2.jpg" target="_blank">http://www.geocities.com/eawfuk/airbag2.jpg</a>
#2

<img src="http://www.geocities.com/eawfuk/sodium_azide.jpg" alt="" />
#3

to bad the NaN3 isn't pure, they also contain some Silicon dioxide and iron oxide...extracting the NaN3 from the pellets wouldn't be safe, as the solution quickly vaporises... and it is highly toxic! :(

Cya

[a_bab]

It's true that sodium azide will be decomposed by lots of chemicals, but it's as safe to extract it from the pellets as extracting table salt <img border="0" title="" alt="[Wink]" src="wink.gif" /> assuming that you'll wear gloves. SiO₂ is insoluble in water, Fe₂O₃ also, so it should be quite simple. I have some sodium azide and it doesn't react with water, but it does react with Pb acetate :D
The idea of using the pellets as they are in order to produce lead azide is shitty. You'll get a mix of lead azide, (sand) and iron oxide. And iron oxide is a well known catalist for many *pyro* reactions, so it may sensitise the lead azide.

[nbk2000]

You could deliberately decompose it to hydrogen azide with sulphuric acid and bubble the gas through NaOH to reform pure NaH3, leaving the sand and rust behind in the acid flask.

A mix of lead azide and sand is used as the primary for the toe-poppers in my PDF. Maybe you could simply react the crushed pellets wtih the lead acetate and use it as-is in the toe-poppers.

[Mr Cool]

I wouldn't recommend deliberatley making HN3 unless you either want a toxic gas or you have a very good fume cupboard, it's apparently VERY toxic, fast acting, and even if you could get to a hospital there's nothing they can do to help (the perfect home-made toxic gas?). Although NBK's method would be a good way of purifying it, if it could be done safely.

I think I'll try hacking one open now. The way I was going to do it is like this: you know the big vent holes around the circumference of the unit? Well I was going to try cutting through the metal between the holes, and then lifting off the top half, taking away all the filters and pouring out the pellets. Since you've already had a poke around inside, could you tell me if you think it would work? Or would your method be simpler? I doubt heat due to friction will present any risk, since there's about 500g of metal acting as a heat sink. First I'll try unscrewing it with some big clamps for leverage, because then I could use the case to store it in, since I won't be using 100g at once.

Another possibility is dissolving out the NaN3 with distilled water + NaOH. This might also seperate out the insoluble stuff at the same time, but I didn't want lots of azide solution around, too much risk of HN3 and contamination.

But if you were prepared to make HN3, you could make all kinds of azides like N2H5N3 (hydrazinium azide), which is apparently a very powerful explosive. It's a pitty that both reactants are so toxic. I bet NH4N4 is quite similar though. Has anyone got any info on the explosive properties of these? I looked, but couldn't find any.

[a_bab]

NBK's method is dangerous not only because of the toxicity on HN₃, but also because HN₃ is an explosive itself. It can be decomposed by organic traces or local heating iven in vapour state, just like NCl₃.
But is the best because you don't have to worry about filtering, etc.

[mongo blongo]

I was wondering about how much Hydrazide gas escapes from a warm concentrated solution (in H2O)? How well does sodium hydroxide prevent this? I am always worried about getting poisoned with this stuff and I know someone who has (from the HN3)! If you drink some strong alcohol when poisoned it will stop brain swelling.

<small>[ April 08, 2002, 10:13 AM: Message edited by: mongo blongo ]</small>

[Anthony]

MrCool, your idea was the first way I tried. I was drilling through one of the large holes in the metal band around the circumference, but I stopped as I was worried about drilling into the unknown.

I'm not sure how well the method would work, once you're in about 10mm you've got a 3mm wall of Aluminium to go through before you get into the sodium azide chamber. Probably work with some patient drilling. Props to you if you manage to get the cap unscrewed:)

I'll make some distilled water, add a little NaOH drop in a small chunk of the NaN3 and see if any gas is elvolved. Seeing as I *still* (no pun :) ) haven't got a proper still set up, I'll cheat and suspend a clean sponge over a boiling pan of water (the old navy/explorer method).

Edit: Point about ethanol consumption well noted, it'll go on my list of yet another good reason to get leathered...

<small>[ April 08, 2002, 11:07 AM: Message edited by: Anthony ]</small>

[Dr. Kollossos]

Excuse me, but does an airbag really contains NaN3? My chemistry teacher told me so, but near the place were i life is an explosive plant :D that produces very fine hexogen for airbags... Also, as you can believe the mechanics, the airbag has a "safety trigger", that prefends you from taking anything in the bag

[Mr Cool]

Most airbags do contain NaN3, but newer ones might not since there's a big environmental issue about all the tons of NaN3 lying in scrap yards. Lol, getting some hexogen ones would be nice!
I tried unscrewing it using two long clamps (one 2 feet long, one 3 feet long). Plenty of torque, but I couldn't get enough grip on the top. So I'll have a go with a saw...

[Anthony]

That ali's too soft to grip but still tough enough to make hard work of sawing:)

This one definitely contains NaN3 as amongst other warning stickers on the unit, there's one which reads "Warning! Contains sodium azide and boron potassium nitrate" - bit of a give away really:)

I was under the impression that scrap yards have to remove airbag units and have them properly dispossed off. A garage I worked at briefly had to remove and fire airbags from any car that they sent to the scrappy.

[cutefix]

Azide free airbag inflator usually contains active ingredient composed of fine particles of 60%RDX and 40%AN.The problem with this formulation is it will form moisture that will condense on metal surfaces as ice if the airbag is ignited in subzero climate( if accident occurs during winter ).The resulting condensation will decrease the volume of gas needed for proper inflation.Therefore the hexogen based composition is not robust as compared to azide inflators.The latter will likely remain specially in low cost cars made from Asian countries.
You may wonder why there is the presence of ammonium nitrate;it was for the purpose of improving oxygen balance during combustion as pure RDX is has negative oxygen balance,and the combustion products will contain lots of CO.If that happens the supposed accident victim will survive collision; but if there is carbon monoxide as part of combustion products,that will likely kill the victim as well due to its toxic effects.specially if the inflated bag gets punctured,Or from leaks.The desired combustion products should be CO2,N2,and H2O.
There are developments in this area in which RDX is replaced with keto-RDX which contains more oxygen per molecule;so that the added oxidant will be minimized that a typical ratio of 75/25 is practical.This will give better gas volume with lesser moisture condensation.Othere formulations use metal perchlorates /with RDX which give more oxygen but will create more residues which is not desirable as well.Therefore keto-RDX/ AN is still superior for its clean burning properties.

[Polverone]

[Directed at Anthony] Okay, I've got to ask again... Where do you get airbag units? You said "I was under the impression that scrap yards have to remove airbag units and have them properly dispossed off." So nosing around at the local car junking place probably won't do much good. Info I found browsing the net indicated that airbag units by themselves cost $500-$600. That's an awful lot for NaN3 in an inconvenient package. So much that I'd sooner buy it outright from a lab supplier.

[johnn 99]

Quote [ The aluminum detonating chamber is die-stamped together and cannot be disassembled nondestructively.] REF: Ragnars Homemade detonators. pg.56 By the way I was at the junkyard last weekend, and the vehicles definitely still had intact airbags. (western U.S)

[Anthony]

Sorry, I forgot to answer the question. I got the unit from a fellow forum member. I have no idea how he came by them, if he wants to say something it's up to him.

I don't know how much a scrap yard would charge for an airbag unit, if they're clued into what they're apparently worth then probably a lot. My recommendation would be to look at the abandoned stolen cars you see lying about until you find one new enough to have airbags.

"cannot be disassembled nondestructively"

That doesn't mean that you can't disassemble the unit without it discarging, it means you can't do it without destroying the casing, unless this is what you meant to imply?

[johnn 99]

What I meant to imply was that he doesn't seem to think it's possible to unscrew them. Whether that is true or not, I don't know, as i haven't played with them myself. That is what the book said for whatever it's worth.

[Arkangel]

Cutefix, surely the bags leak completely anyway. My understanding is that they are a veeerrrryyyy fine and tough cloth that inflates with the gas, and then almost instantaneously begins to deflate as the gas passes through the material. This is to allow you to make an exit from the car, something impossible if you're trying to fight your way past a big fuck off balloon.

CO is only really dangerous where you're exposed to it for an extended period? In an accident, you might get stuck in the car, but if so, windows are often broken, doors burst etc; can't see this being a problem.

[cutefix]

You have apoint there Arkangel.But these azide-free inflators were designed with mixtures with good oxygen balance in mind.There might be some other formulation aside from nitramine based explosives;but then the design would still be geared for maximum safety;and that includes clean combustion products.
BTW ,Azides give mostly pure nitrogen during decomposition,which is non toxic if compared to carbon monoxide which has notorious reputation.

[Arkangel]

Agreed. I wasn't making a point on chemistry (as I'm a chemical moron), just the physical side of airbag design. I defer to your clearly superior knowledge <img border="0" title="" alt="[Wink]" src="wink.gif" />

[vulture]

Hmm, if NaN3 decomposes, doesn`t it leaves metallic sodium behind? That seems pretty dangerous to me. For example, a car gets involved in an accident and then the coolant leaks, dripping over the airbag inflator, that would not only be a very violent reaction but also pose a severe explosion hazard from the evolving hydrogen gas.

[J]

In my chemical catalogue, the only dangers associated with NaN3 are 'Very toxic if swallowed' and 'Contact with acids liberates very toxic gas'. If it did decompose from flame/shock on its own, I would assume there'd be something written about this (there are various explosives listed in the catalogue, all with warnings). The other chemicals in the pellets are probably required for it to decompose explosively.

I assume the reaction would go something like:

NaN3 + SiO2 ==> NaSiO3 + N2

The Iron Oxide is probably a catalyst. This is just a guess mind.

On this note, have you done any flame tests Anthony?

<small>[ April 12, 2002, 05:03 PM: Message edited by: J ]</small>

[mongo blongo]

If anyone wants to compare any such results with PURE Sodium Azide (lab standard) then I can be of assistants! <img border="0" title="" alt="[Wink]" src="wink.gif" />

[Anthony]

I hope you guys are grateful, I had to put some trousers (yankee: "pants") on to test this :)

I held one of the pellets in a naked flame with tongs, it took a few seconds for it to do anything, but it combusted rapidly, in a binded pyro composition fashion.

[Zach]

is wearing pants a rare occurence for you Anthony? :D
but seriously, how hard is the airbag combustion chamber thing to extract from a steering wheel? or is it a bit deeper in the steering column? i ask because i know where i can easily get one from a newer car, i just have to be fast about it (5-6 min. max).

[nbk2000]

I'm glad someone else said it first. <img border="0" title="" alt="[Wink]" src="wink.gif" />

They have that whole "Kilt" thing going on over there so pants may be a rarity. <img src="http://www.candlepowerforums.com/ubb/icons/icon18.gif" alt="" />

Is it true they don't wear knickers (colonies ( :p ): underwear) unter them?

Seriously, the azide pellets must burn a lot faster under pressure of confinement. Much like smokeless powder just burns in the open, but practically explodes under confinement.

You should try it wrapped tightly in paper. Use a hotwire ignitor to set it off. I'd think it'd burn a LOT faster than.

After all, all those pellets have to burn in something like 10 milliseconds to be effective as airbags, so something's going on to make them burn that fast.

[Anthony]

During the summer I rarely wear "pants" indoors, it's just too hot and uncomfortable. It's not summer now but I'd just got back from work which meant dirty, sweaty, beer/cider/wine/godknowswhatelse soaked clothes that I don't want to sit about it.

Yep, the Scots don't wear anything under their kilts, makes for excellent flashing/mooning, but must be damn chilly considering their climate... Not sure what you're referring to when you say "knickers", that's womens underwear, perhaps best not go asking a huge, hairy scot in a kilt if he wears women's underwear :)

I divulge... :D

The NaN3 pellet probably burnt faster than I described, the first time it ignited it actually blew itself into several chunks, when it does burn it does so in the blink of an eye, but it is a progressive burn, not like igniting AP or HMTD. Although as a powder it might go like the peroxides.

[Demolition]

IIRC in a physics book at school it states that an airbag (45 litres) is inflated in .45 seconds using NaN3.Ill check it out when I go back to school.