Azide, formation from a hydrazine

Azeotropic distillation, 20,66,106,23,38 Azide, formation from a hydrazine, 22,96 Azobenzene, 22, 28 Azoyl chloride, 25, 87 Azulene, removal from a hydrocarbon, 24, 86... 

Use of nitrous acid to liberate a free keto-acid from its semicarbazone caused formation of hydrogen azide which was co-extracted into ether with the product. Addition of silver nitrate to precipitate the silver salt of the acid also precipitated silver azide, which later exploded on scraping from a sintered disc. The possibility of formation of free hydrogen azide from interaction of nitrous acid and hydrazine or hydroxylamine derivatives is stressed. 

One of the first polysaccharide derivatives used for insolubilization was the acid azide (or hydrazide) of 0-(carboxymethyl)cellulose. Treatment of the methyl ester of O-(carboxymethyl) cellulose with hydrazine gives the hydrazide 31 which, with nitrous acid, yields the azide (32). The azido group evidently reacts with the free functional groups of lysyl, tyrosyl, cysteinyl, and seryl residues (see Ref. 436), and evidence for formation of a covalent bond, as in 33, comes from the fact that the... 

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