关键词: 类水滑石, 催化活性, 寿命, 酯交换反应, 碳酸二甲酯, 碳酸二苯酯

he catalytic activities of five samples of hydrotalcite-like compounds (HTLC) with different combinations of cation and the life time of ZnAl, MgAl-hydrotalcite catalysts have been investigated for transesterification of DMC and PhOH. The results show that the catalytic performance of HTLC was related to the character of involved cations. While the catalytic activity was influenced by trivalent cations, the life time of catalysts was influenced by divalent cations. From the investigation of the reason for the deactivation of hydrotalcite-like catalysts, it was found that the characteristic layered structure of HTLC was the key factor to their catalytic activities. Once the layered structure collapsed, the activities were lost. When the molar ratio of PhOH to DMC was 2∶1, the mass fraction of catalyst to the total reaction mass was 1% and the reaction time last 8 h, MgAl-hydrotalcite showed the best catalytic performance: the conversion of DMC reached 51.8%, the selectivity to DPC and MPC reached 94.2%, and the catalytic activity kept unchanged after being used five times. The catalytic performance of MgAl-hydrotalcite was obviously better than the other solid catalysts reported in this transesterification.

Key words: hydrotalcite-like compound, catalytic activity, life time, transesterification, dimethyl carbonate, diphenyl carbonate