A study on the heterobinuclear site of Co(salen)/TiO2-SiO 2 catalysts in the oxidative carbonylation of aniline

Abstract

Titania-silica immobilized Co(salen) complexes containing the heterobinuclear site were prepared by the sol-gel method for the catalytic synthesis of methyl N-phenylcarbamate (MPC) by the oxidative carbonylation of aniline. It was found that the Ti: Si mole ratio had an important effect on the catalytic performance of Co(salen) complexes. When the Ti: Si ratio was 0.1, titania-silica supported Co(salophen) showed the best catalytic activity. Under the reaction conditions, Co(salophen)/TS-0.1, 0.5 g, aniline 11 mmol, methanol 25 ml, KI 2.2 mmol, CO:O2 9:1, total pressure 6 MPa, 150 C, 3 h, the conversion of aniline and the selectivity of MPC were 60.7 and 88.1%, respectively. The XRD studies showed that titania was highly dispersed in the silica matrix. Co(salophen)/TS-0.1 was reused five times with no significant loss of the activity, and no Co leaching was observed in the reaction. Copyright © 2009 John Wiley & Sons, Ltd.