Polymerization reaction with diphenylphosphoryl azide. Preparation of polyamides, polyureas and polyurethanes

The preparation of various polyamides, polyureas and polyurethanes by polymerization reactions with diphenylphosphoryl azide (DPPA) was investigated. Various polyamides were obtained very conveniently by polymerization of aminocarboxylic acids or copolymerization of dicarboxylic acids and diamines. Polyureas were mainly obtained by conversion of dicarboxylic acids to acyl azides with DPPA and then to isocyanates, followed by copolymerization of these diisocyanates with diamines. Further, the polymerization of some aminocarboxylic acids that have an amino group of low nucleophilicity (such as p ‐aminobenzoic acid) was found to give polyureas instead of polyamides by direct polymerization. Polyurethanes were also obtained from dicarboxylic acids and diols through the Curtius rearrangement of acyl azides, similarly as in the polyurea preparations. The products were identified with the help of IR spectra and elemental analyses, and their molecular weights were evaluated viscometrically.