Photochemical and thermal decomposition of diphenylamine diazonium salts

Abstract

The photochemical and thermal decomposition of diphenylamine-4-diazonium salt (DDS), N-methyl diphenylamine-4-diazonium salt (NMDDS), 3-methoxy diphenylamine-4-diazonium salt (MDDS), carbazole-3-diazonium salt (CDS) in ethanol 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, MDDS and NMDDS are diphenylamino-4-ethyl ether, carbazole-3-ethyl ether and the corresponding substituted diphenylamino-4-ethyl ethers. In thermal decomposition, the diphenylamine (DA), carbazole (CZ) and substituted DA were obtained as only one product in each case. For the decomposition of MNDDS, which has 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 photochemical and thermal decomposition for DDS, CDS and substituted DDS are discussed.