PHOTOLYSIS OF AROMATIC AZIDES ON A SILICA-GEL SURFACE

The photolysis of aromatic diazides (DA) on a silica gel surface under ambient air was studied. The main photolysis product is an insoluble polymer residue containing the azo groups; its yield is 80 - 90% decom posed DA. A mechanism was suggested that implies interaction between n eighboring triplet nitrene molecules or between a nitrene and the azid e group of a neighboring molecule to form the polymer as a principal r eaction of nitrenes on the silica gel surface. The chain termination o ccurs as a result of hydrogen abstraction by a triplet nitrene from th e neighboring molecule to yield die primary amino groups. The DA photo lysis is accompanied by the intramolecular rearrangement of DA molecul ar fragments linking the benzene rings and by the formation of oxidati on products: nitroso and azoxy compounds and nitroxyl radicals.