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负载型双核金属乙氧基配合物催化剂 Cu2 (OEt) 2 /Si O2 采用表面改性法制备。运用滴定、IR、DSC和超临界反应技术对催化剂的表面结构、化学吸附性质和反应性能进行了研究。结果表明 :负载型双核金属乙氧基配合物 Cu2 (OEt) 2 /Si O2 中 Cu2 + 与载体 Si O2 表面 O2 -以双齿配位形式键合 ,存在Cu2 (OEt) 2 双核结构 ;二氧化碳在催化剂表面吸附形式形成桥式和乙氧碳酸酯基物种两种吸附态 ,丙烯则只有一种分子吸附态 ;在超临界的反应条件下 ,二氧化碳和丙烯在 Cu2 (OEt) 2 /Si O2 催化剂上可以高选择性地合成甲基丙烯酸 ;反应物分子共吸附于催化剂表面 ,同一活性基元以及羧酸根与丙烯解离吸附态的形成是反应顺利进行的关键因素。
The supported binuclear metal ethoxylate catalyst Cu2 (OEt) 2 / Si O2 was prepared by surface modification. The surface structure, chemisorption properties and reactivity of the catalyst were studied by titration, IR, DSC and supercritical reaction. The results show that Cu2 (OEt) 2 binuclear structure exists in Cu2 (OEt) 2 / Si O2 supported Cu2 (OEt) 2 / Si O2 and O2 - The adsorption on the surface of the catalyst formed two adsorption states of bridge and ethoxy carbonate-based species, while propylene possessed only one molecular adsorption state. On the Cu2 (OEt) 2 / Si O2 catalyst under supercritical reaction conditions Methacrylic acid can be synthesized with high selectivity. Reactant molecules are co-adsorbed on the catalyst surface. The formation of the same active group and the dissociative adsorption of carboxylate with propylene are the key factors for the smooth reaction.