Photochemical and thermal decomposition of diphenylamine diazonium salts

The photochemical and thermal decomposition of diphenylamine-4-diazonium sa lt (DDS), N-methyl diphenylamine-4-diazonium salt (NMDDS), 3-methoxy diphen ylamine-4-diazonium salt (MDDS), carbazole-3-diazonium salt (CDS) in ethano l and N-methyl-2-nitrodiphenylamine-4-diazonium salt (MNDDS) in water were studied. It was found that, in photochemical decomposition in ethanol, the major products (>70% of the total product) obtained for DDS, CDS, NMDDS and NMDDS are diphenylamino-4-ethyl ether, carbazcle-3-ethyl ether and the cor responding substituted diphenylamino-4-ethyl ethers. In thermal decompositi on, the diphenylamine (DA), carbazole (CZ) and substituted DA were obtained as only one product in each case. For the decomposition of MNDDS, which ha s a strong electron-withdrawing nitro group on benzene nuclear at the meta site of the diazonium group, the decomposition products are identical, both in photochemical and in thermal decomposition. The mechanisms of photochem ical and thermal decomposition for DDS, CDS and substituted DDS are discuss ed. (C) 1999 Elsevier Science S.A. All rights reserved.