Waste-Free Quantitative Gas/Solid Diazotation Using Nitrogen Dioxide and Triazene Synthesis, Both Avoiding Liquid Phases

Article abstract of DOI:10.1002/prac.19973390145

Solid diazonium nitrates (2a-j) are quantitatively obtained by reaction of crystalline anilines (1a-j) with gaseous nitrogen dioxide. Solid diazonium salts react quantitatively with dimethylamine to give the triazenes (4a-j). Wastes that are typical for the previous syntheses of these compounds in solution are avoided. Atomic force microscopic (AFM) investigations indicate long-range molecular movements due to phase rebuilding. The features thus formed are related to the known crystal structures of the starting anilines. The diazotations run to completion, because, after accumulation of product molecules, phase transformation to give the product lattices leads to crystal disintegration and thus to formation of fresh surface over and over.