Sciencemadness Discussion Board

Help with the synthesis of Sodium Azide + Issues

Rhodanide - 21-3-2018 at 05:39

Hi all,
A few days ago, I again tried the synthesis of Sodium Azide from NaOH, Isopropyl Nitrite, and Hydrazine Hydrate. Being me with my luck, it didn't work and nothing precipitated besides Ca(OH)2 from the CaCl2 which was in the Hydrazine Hydrate-EtOH to dry it :mad: .
After this second huge disappointment, I decided to destroy anything that may be in the solution, so I added some 35% H2O2.
Something solid precipitated, which I have no idea what it could be. It's soluble upon addition of water, and I'm thinking it's NaN3. How do I deal with this?
Thanks,
-R

[edit by j_sum1] added to title for clarity.
Interesting question. I hope someone has an answer.

[Edited on 21-3-2018 by j_sum1]

[Edited on 3-21-2018 by Rhodanide]

Texium - 21-3-2018 at 05:58

Descriptive thread titles, please

Edit: Thank you ;)

[Edited on 3-21-2018 by Texium (zts16)]

EdsonEGDN - 21-3-2018 at 07:03

How much water was in hydrazine hydrate?


I did it and it worked, and I even prepared the hydrazine, the yields were decent.The sodium azide quickly appears soon after in the alcoholic solution within a few minutes and has a considerable amount of sodium azide , the reaction is exothermic .It is probably the water in the Hydrazine that dissolved the sodium azide.

Rhodanide - 21-3-2018 at 09:34

Quote: Originally posted by EdsonEGDN  
How much water was in hydrazine hydrate?


I did it and it worked, and I even prepared the hydrazine, the yields were decent.The sodium azide quickly appears soon after in the alcoholic solution within a few minutes and has a considerable amount of sodium azide , the reaction is exothermic .It is probably the water in the Hydrazine that dissolved the sodium azide.


It's Hydrazine Hydrate dissolved in denatured alcohol out of the can. What can I do to possibly crash it out? There is a bit of precipitate, but I'm sure that it has to be Ca(OH)2.
Edit: Would it be insoluble in Acetone or Acetonitrile?? Those are two solvents that I have which are sort of similar to alcohols, I also have a bit of Methanol as well. If it DOES precipitate, I don't want anything else to crash out, either... Also, I want to keep my nice, dry Acetonitrile. :)
Second Edit: The Hydrazine soln. was kept for a few hours over CaCl2 but there was a cloudiness or turbidity observed and a precipitate of some kind. This precipitate settles after a day or two, but only by 1cm or so. It tried to filter but the precipitate didn't want to comply.

[Edited on 3-21-2018 by Rhodanide]

[Edited on 3-21-2018 by Rhodanide]

Chemi Pharma - 23-3-2018 at 04:42

Did you follow the directions given by ChemPlayer in his YouTube Video about making sodium azide from hydrazine sulfate and isopropyl nitrite?

I think his video is self explaining as well, affording high yields. See at:

https://www.youtube.com/watch?v=qOSOXVSFdb0

[Edited on 23-3-2018 by Chemi Pharma]

Rhodanide - 23-3-2018 at 05:13

Quote: Originally posted by Chemi Pharma  
Did you follow the directions given by ChemPlayer in his YouTube Video about making sodium azide from hydrazine sulfate and isopropyl nitrite?

I think his video is self explaining as well, affording high yields. See at:

https://www.youtube.com/watch?v=qOSOXVSFdb0

[Edited on 23-3-2018 by Chemi Pharma]



Funny you say that, because that's what I followed.

chemplayer... - 26-3-2018 at 02:14

Perhaps convert the hydrazine hydrate to the sulfate and then follow the same exact process (freebasing into alcohol using NaOH granules)?

When we've done this we've found two things which can stuff things up:
1. If you're using IPA as the alcohol and it's slightly oxidised - the acetone present reacts with the hydrazine straight off and kills the yield.
2. Presence of water reduces the yield of crystals as sodium azide is extremely soluble in water.

Rhodanide - 26-3-2018 at 06:31

Quote: Originally posted by chemplayer...  
Perhaps convert the hydrazine hydrate to the sulfate and then follow the same exact process (freebasing into alcohol using NaOH granules)?

When we've done this we've found two things which can stuff things up:
1. If you're using IPA as the alcohol and it's slightly oxidised - the acetone present reacts with the hydrazine straight off and kills the yield.
2. Presence of water reduces the yield of crystals as sodium azide is extremely soluble in water.


Hey CP, good to see you here.
I followed your procedure verbatim except for that I used denatured EtOH straight out of the can. How should I destroy any NaN3 which may be present? I don't want to deal with making it anymore if I can buy it. Too many screw ups with that toxic of a chemical. (I say that but I had a sep funnel with 20mL of Chloropicrin in it topple over in the wind, but I somehow caught it)

chemplayer... - 29-3-2018 at 17:10

Unless you've got access to absolute ethanol it might be that methanol (or even IPA if you can be sure it's pure and containing no acetone) are better solvents for this reaction as they are easier to obtain water-free. KOH might end up being the better base to use too in this case as it may be more soluble in these (not totally sure about that though). Maybe the water interferes or perhaps it just dissolves the product and stops it crystallising.

Probably a smart idea not to pour azides down the drain immediately or anywhere that they could end up in contact with heavy metals. Nitrous acid apparently reacts quickly so perhaps dilute the solution down, chill it, add an excess of sodium nitrite, and then very carefully add dilute HCl drop-wise to neutralise residual alkali and then destroy the azide. Needless to say this is one you want to do with ventilation because the NO (and subsequently NO2) are toxic, and you don't want to risk evil migraine inducing hydrazoic acid vapours.

MrHomeScientist - 30-3-2018 at 12:55

Quote: Originally posted by Rhodanide  
How should I destroy any NaN3 which may be present?

You may have seen this already, but Wikipedia claims
Quote:
Sodium azide can be destroyed by treatment with nitrous acid solution:[9]
2 NaN3 + 2 HNO2 → 3 N2 + 2 NO + 2 NaOH

Although getting nitrous acid may introduce its own problems.

Amos - 30-3-2018 at 14:19

it isn't like the azide is going anywhere, right? You can perhaps evaporate the mixture down to get more crystals or just destroy it with nitrous acid as MrHomeScientist mentioned. I'm assuming you have the necessary materials being that isopropyl nitrite was one of your reagents.

Melgar - 31-3-2018 at 10:42

Denatured alcohol almost always contains acetone. Adding H2O2 to it in the presence of an acid catalyst can create TATP and other not-so-fun stuff. Not sure if that's what's up, but I usually steer clear of denatured alcohol, just because at least in the US, they don't have to disclose everything that's in it, since it's only meant to be used as a solvent and a fuel.