Sciencemadness Discussion Board

Sodium Azide

Cappy - 13-4-2003 at 19:21

Does anyone have information on sodium azide? It doesn't seem to be a popular explosive except for use in airbag inflation. I suppose lead azide must have advantages to justify the effort in making it from sodium azide.

Do you think atomized lead or sodium would be more hazardous as products of the explosion?

madscientist - 13-4-2003 at 19:25

I think sodium azide simply isn't a very powerful explosive.

Lead is definitely worse for the environment, but sodium spells a far greater fire hazard.

Madog - 14-4-2003 at 03:47

yeah, sodium azide just burns.

thy cnat use lead azide as a source of pressure in air bags becase it will just detonate and pepper the poor driver with pieces of metal going at high velocities.

im not sure if sodium azide can make the ddt but aparently not easy enough for it to be safely used in airbags.

sodium azide

mick - 10-10-2003 at 09:42

organic azides can go bang.
Never let the stuff (sodium azide) hit acid, its x times worse than cyanide.

palpy - 12-10-2003 at 08:28

yeah, and beware of sucrose, it's y times worse than cyanide... :mad: :D

but you're right azoimide HN3 is a very poisonous gas (besides that it's also a very powerful and sensitive explosive when liquidified - VoD>8000m/s )

azides

mick - 23-10-2003 at 09:04

sorry about the x times. what I think I meant is that any damage from HN3 could be a lot more permanent than from cyanide since it is very reactive, attacking DNA and stuff (and sucrose) causing the bonds to break and join together in the wrong way.
True story-
Some one was distilling something like 100g benzyl azide (28 years ago), this had been done before by more experienced people with no problems. This time for some reason (I do not know why, maybe the temperature was a bit higher, maybe the equipment was dirty with an unkown catalyst or wet, maybe the weather was different) but the thing went bang. Luckily some one was there to put her out, luckily she was wearing safety glasses (usually hair grows back). Unlucky she was wearing an acrylic jumper which meant more than two years of plastic surgery (if she had had cotton or wool on I don't think the damage would have been anywhere as bad).
Mick

OH MY

chloric1 - 23-10-2003 at 10:00

I feel sorry for the tech!! Yeh I know azides are bad but I will really have to watch it if and when i get my hands on them.

By the way anybody try the semicarbazide route ( react with NaNO2)?

[Edited on 10/23/2003 by chloric1]

chemoleo - 25-10-2003 at 09:36

btw NaN3 does not damage DNA etc, at least not in the primary reaction (but maybe it does cause damage due to secondary effects). As far as I remember it binds inside your mitochondria to the iron clusters in your respiratory chain proteins, thus rendering them useless for the oxido-reduction cycle. Hence internal suffocation ensures...
It binds even better (tighter) than CN-, that's why it's more poisonous. Also, NaN3 is commonly is used as an antibact/fungal compound in industry, labs etc (but not for medical purposes I should think!), it's very effective.... have a guess why !

Theoretic - 17-11-2003 at 07:48

Sodium azide should be synthesizeable like this:
1)2N2H4 + N2O3 => 2HN3 + 4H2O.
2)HN3 + NaOH => NaN3 + H2O
A tiny amount of water is required to initiate reaction 1. Then the reaction escalates more and more... :cool:

madscientist - 17-11-2003 at 08:57

N<sub>2</sub>O<sub>3</sub> (the anhydride of nitrous acid) isn't stable; it exists only as an equimolar mixture of NO and NO<sub>2</sub>. Because of this, HN<sub>3</sub> is better prepared via reaction of hydrazine and aqueous nitrous acid.

Potassium Nitrate contamination

cyclonitepyro - 6-12-2011 at 08:37

How would potassium nitrate be removed from sodium azide? Or if not would the azide in solution react to form potassium azide rather than lead azide I think the lead would have a higher affinity but would there still be potassium azide contamination?

hissingnoise - 6-12-2011 at 09:12

Quote:
How would potassium nitrate be removed from sodium azide?

The synthesis of Pb(N<sub>3</sub>;)<sub>2</sub> is not affected by the presence of KNO<sub>3</sub> in a solution of NaN<sub>3</sub> . . .
Because of lead azide's limited solubility, the salt will precipitate in practically quantitative yield when Pb ions are added to such solutions.



AndersHoveland - 6-12-2011 at 17:16

How many threads does this forum have on sodium azide?

http://www.sciencemadness.org/talk/viewthread.php?tid=15406
http://www.sciencemadness.org/talk/viewthread.php?tid=253
http://www.sciencemadness.org/talk/viewthread.php?tid=10875
(the last thread is titled 'NAN3 synth' so you could be forgiven if it did not appear in a search)

[Edited on 7-12-2011 by AndersHoveland]

niertap - 30-1-2012 at 00:00

The reasons the silver or lead salt are exponentially better explosives are...

-because they have about 2.5x the density of the sodium salt. The inertial confinement this provides is incredibly important in a primary.

-The pb/ag salts are essentially insoluble, while the na salt is quite soluble.

-lastly, pb/aq metal is quite happy being the pure metal, while it take a lot of energy to to free up pure sodium metal. This plays a huge part in the detonation, as I believe it is the rate limiting step or at-least plays a huge part in determining the final energy of the products.



Edit:
As far as synthesis goes, the only possible way for those without a death wish would be...

sodium metal with ammonia to form the amide
react the amide with nitrous oxide to form the azide.



[Edited on 30-1-2012 by niertap]

AndersHoveland - 31-1-2012 at 00:14

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

Barium azide, however, is a sensitive explosive, with a drop height value of 10cm. It appears to be relatively insensitive to impact but highly sensitive to friction.
H. Ficheroulle, Mem. des Poudres. 33, 7 (1956)
The temperature at which barium azide explodes is apparently highly variable, values have been reported between 152° to 221°C.
Calcium azide begins to thermally decompose above 110 °C, and explodes at 158°, it is more explosive than either strontium or barium azide.
Lithium azide has only moderate explosive properties. Decomposition of lithium azide only forms lithium nitride and nitrogen. It can survive hammer blows without detonation.

The enthalpy of formation for barium azide from its elements is actually slightly negative, -5.3 kcal/mole. The formation of barium nitride is very favorable, the compound having an enthalpy of formation of -89.9 kcal/mole. "Nitrogen Burning of Metals", G. Petrov, Combustion, Explosion, and Shock Waves, Volume 11, Number 3, 309-312 The decomposition of barium azide tends to form barium nitride, although some elemental barium is also forms.

Alkali Nitrides
Lithium is the only alkali metal that burns in nitrogen. Nitrogen gas can be passed into molten sodium without reaction. Sodium nitride can be formed by electric discharge of elemental sodium and nitrogen. Further action results in formation of sodium azide. With potassium instead of sodium under the same conditions only the azide forms, but potassium nitride can be obtained by reaction of the elements using silent electrical discharge at low pressure. Potassium nitride is even less stable than sodium nitride.

[Edited on 31-1-2012 by AndersHoveland]

Phantom - 31-1-2012 at 13:22

This not actual a primary explosive, but it is used in the manufacture of lead azide.
Its preparation is extremely dangerous, because of the use of hydrazine.

nezza - 14-2-2012 at 00:57

Sodium azide decomposes relatively quietly when gently heated if it is pure and preferably under reduced pressure. Rapid heating causes rapid decomposition. Heating sodium azide under vacuum is one way of making pure sodium, but again I stress that the reagent must be pure.

AndersHoveland - 14-2-2012 at 02:00

Or just heating NaN3 in an atmosphere of pure nitrogen, with a little venting tube to let out the extra gases produced...

quicksilver - 14-2-2012 at 09:00

Possibly one of the more interesting azides is the mercury salt due to it's potential for serious sensitivity when re-crystallized. A gentleman named Lipinov (sp?) was one of the few to examine why both the cupric and mercury salts have a potential for hyper-sensitivity. Experiments had been attempted to limit crystal growth as they were shown to be effective with lead azide's needles. Silver azide became the later military and industrial standard due to a lack of strong potential for crystal formation in general. But in the case of the cupric salt, no manner of blunting crystal growth could temper it's sensitivity (which is extreme). The mercury salt appeared to be crystal structure related as the material appeared to be less sensitive when synthesized. However ANY attempt to re-crystallize was met with hyper sensitivity. Even when the material showed no outward crystal structure (ruff granules, similar to PbN3 synthesized with a hot dextrine wash) working with micro-gram levels were the only method of not destroying a slide, sample cup, damaging a lens, or ruining a sample. HgN3 is still not used due to the potential for time elements or oxygen exposure to alter it's performance.