CuCl/SiO2-TiO2 催化剂的结构及其催化甲醇氧化羰基化反应性能

 在微波辐射条件下, 将 CuCl 快速分散到载体表面制得 CuCl/SiO2-TiO2 催化剂, 利用 X 射线衍射、透射电镜、N2 吸附-脱附、热重、H2 程序升温还原和 CO 程序升温脱附对催化剂进行了表征. 结果表明, 微波辐射制备的催化剂中 CuCl 和载体发生了强相互作用, 比传统加热制备的催化剂中形成更多的易还原铜物种, 吸附 CO 的能力更强. 在甲醇液相氧化羰基化反应中, 微波辐射制备的催化剂上甲醇转化率为 11.7%, 碳酸二甲酯选择性达 96.5%, 高于相同条件下传统加热制备催化剂的活性.

Structure of CuCl/SiO2-TiO2 Catalyst and Its Catalytic Properties for Oxidative Carbonylation of Methanol

Microwave heating for a mixture of CuCl and SiO2-TiO2 support was used to prepare a CuCl/SiO2-TiO2 catalyst with high dispersion of CuCl on the support surface in a short time. X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption, thermal gravimetric analysis, H2 temperature-programmed reduction, and CO temperature-programmed desorption were carried out to examine the bulk and surface properties of the CuCl/SiO2-TiO2 catalyst. The characterization results showed that in the CuCl/SiO2-TiO2 catalyst prepared by microwave heating, a great amount of CuCl particles strongly attached to the SiO2-TiO2 support as compared with that prepared by con-ventional heating, resulting in a lower reduction temperature of copper species and a stronger adsorption to CO. Microwave heating also caused that the mass loss temperature of part CuCl was higher than 1 200 oC, which could be attributed to the formation of a strong Cu–O coordinate bond between CuCl and the SiO2-TiO2 support. Catalytic test results showed that the CuCl/SiO2-TiO2 catalyst prepared by mi-crowave heating exhibited methanol conversion of 11.7% and dimethyl carbonate selectivity of 96.5%, higher than that prepared by conven-tional heating in liquid-phase oxidative carbonylation of methanol.