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采用表面改性和离子交换相结合的方法制备了Ni2 (OCH3 ) 2 /SiO2 负载型双核金属甲氧基配合物催化剂 ,利用红外光谱 (IR)、程序升温脱附 (TPD)、程序升温表面反应 (TPSR)和微反技术考察了催化剂的表面结构以及CO2 和CH3 OH的化学吸附和反应性能 .结果表明 :Ni2 (OCH3 ) 2 /SiO2 中Ni2 + 与载体SiO2 表面O2 -以双齿配位形式键合 ,甲氧基以桥基形式联结双金属离子形成双核物种Ni2 (OCH3 ) 2 ;CO2 在催化剂表面存在甲氧碳酸酯基物种和桥式两种吸附态 ,CH3 OH则只有一种分子吸附态 ;在 10 0～ 2 0 0℃条件下 ,CO2 和CH3 OH在催化剂上的反应产物主要是DMC和H2 O ;根据反应结果 ,讨论了催化反应机理 .
Ni2 (OCH3) 2 / SiO2 supported dinuclear metal complex catalysts were prepared by a combination of surface modification and ion exchange. The effects of IR, temperature programmed desorption (TPD), temperature programmed surface reaction (TPSR) and micro-reverse techniques were used to investigate the surface structure of the catalyst and the chemisorption and reactivity of CO2 and CH3OH.The results show that Ni2 + in Ni2 (OCH3) 2 / SiO2 and O2- (OCH3) 2 was formed by bridging bimetallic ions in the form of bridging groups. There were two species of carboxylate-based species and bridging species on the surface of CO2, and only one type of molecule was adsorbed on CH3OH The reaction products of CO2 and CH3OH on the catalyst were mainly DMC and H2O at 10 0 ~ 200 ℃. The catalytic reaction mechanism was discussed according to the reaction results.