摘要
用表面反应改性法合成了MoOCl/SiO2 催化剂 .分析测定结果表明 :钼 (Ⅴ )离子在SiO2 表面以双齿配位形式与表面氧键合 ;双核钼 (Ⅴ )间以 μ 双氯基桥联 .用IR ,TPD ,TPSR MS和TPSR IR研究了MoOCl/SiO2 催化剂对CO2 与EO(环氧乙烷 )的化学吸附特性及催化合成EC(碳酸乙烯酯 )的反应性能 .结果表明 :CO2 在催化剂表面形成桥式吸附态 ,桥基配体是表面反应的活性中心 ;EO在催化剂表面也形成桥式吸附态 ;催化剂对CO2 与EO合成EC有良好的催化性能 ,在 1 40℃条件下经过渡态而定向转化为EC .
Silica supported μ dichloro bridged dimolybdenum(Ⅴ) complex catalyst, namely MoOCl/SiO 2, for synthesis of ethylene carbonate (EC) was synthesized by surface modification and substitution of bridging ligands. The bidentate coordination mode of molybdenum(Ⅴ) ions on the modified surface was evidenced by titration and IR spectroscopy. The existence of dinuclear structure on SiO 2 surface was characterized by IR, UV Vis, magnetic analysis and titration method. Chemisorption of CO 2 and EO (ethylene oxide) on the catalyst was studied by IR and TPD MS techniques. Based on the experimental data, CO 2 and EO were proposed to be chemisorbed in the form of bridged structure under the synergy of Lewis acid and Lewis base sites on the catalyst surface. The results of TPSR MS and TPSR IR indicated that CO 2 reacts with EO to EC on the catalyst at 140 ℃.
出处
《催化学报》
CSCD
北大核心
2000年第4期341-344,共4页
关键词
催化剂
碳酸乙烯酯
催化合成
双核钼配合物
合成
dinuclear molybdenum(Ⅴ) complex
supported catalyst
carbon dioxide
ethylene oxide
chemical adsorptionm
ethylene carbonate
