I plan to obtain isocyanates for the production of polyurethane materials using Curtius rearrangement. Please advise me on the reactions and safety of working with azides
You should check the appropriate safety literature and with your institutions safety officer.
If you are going to take carbonyl chlorides to carbonyl azides for the rearrangement ….
be very careful with sodium azide itself - as toxic as sodium cyanide (with the same mode of action), you also need to use a non-metal spatula to work with it (prevents accidentally forming highly explosive aluminum azide). The sodium azide can be explosive if heated or under pressure.
if you have a procedure that does not isolate the carbonyl azides but converts to desired isocyanate in situ that is preferable. The carbonyl azides are also explosion hazards. If you do isolate, only a tiny amount. I have seen in the literature where 25 mg of an azide exploded and took off someone’s hand.
so there is no such thing as an over abundance of caution with azides.
Dear all, attached is a document showing a safe technique to deal with azide. My Regards
Dear Joanna, as long as you are working with sodium azide, you are on the safe side as this salt is not explosive under normal conditions. The main danger associated with sodium azide is that it should never get in contact with acids. This will cause the evolution of highly explosive and toxic hydroazoic acid, HN3. This should be avoided under all circumstances. In any case I suggest that you carry out all reactions in a well-ventilated fume hood. Also try to avoid isolation and organic azide intermediates because of their potentially explosive nature. Just follow a published procedure.
Good luck with your work and best wishes, Frank Edelmann
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