Oxidative carbonylation of aniline with a mesoporous silica gel immobilised Se-functionalised ionic liquid catalyst

摘要

A series of BMImBF_4-templated mesoporous silica gel immobilised Se-functionalised ionic liquids have been prepared. The catalysts were characterised by BET, FTIR and ICP-AES, and the results showed that the content of Se increased from 2.7 to 4.76 wt% with pore volume increasing from 0.83 to 1.26 cm~3 g~(-1). Preliminary tests of this catalyst system on the carbonylation of aniline to afford methyl phenyl carbamate (MPC) indicated that good catalytic activity (higher than 74% aniline conversion with 99% MPC selectivity) could be achieved with higher than 150 mol h~(-1) mol ~(-1) turnover frequency (TOF). TOF and aniline conversion slightly increased with increasing the content of Se from 2.7 to 3.0 wt%, then decreased when the content of Se increased to more than 3.0 wt%, this suggested that 2.7 to 3.0 wt% Se content should be appropriate for MPC synthesis. The appropriate Se content could be obtaineded by adjusting the range of pore volume of mesoporous silica gel from 0.83 to 0.85 cm~3 g~(-1). In addition, the recycling test indicated that there was almost no deactivation of the catalyst when it was reused four times.