One step C-N bond formation from alkylbenzene and ammonia over Cu-modified TS-1 zeolite catalyst

摘要

A Cu doped TS-1 zeolite sample was applied to catalyze the formation of C-N bonds on both the ring and the side chain of toluene, as well as other alkylbenzenes. A yield of 3.4% of toluidine was obtained for the amination of toluene, with a 1.0% yield of nitrobenzene. Cyanobenzene was also obtained as the C-N bond product on the side chain with a yield of 1.0%. The selectivity for C-N bond formation was 52.4%. The catalyst promoted the formation of a hydroxylamine intermediate from ammonia and hydrogen peroxide, and then the instantaneously generated amino cation reacted with the substrate to form C-N bonds on both the ring and side chain. Cyanobenzene was produced from the dehydration of benzylamine, formed via the reaction of ammonia and toluene. The formation of C-N bonds on the ring had an ortho-orientation advantage for mono-substituted-benzenes. With the increase in the number of methyl substituents, the yield of the ring products decreased, which might be caused by steric hindrance.