聚合物负载季鏻盐催化 CO2 与环氧化物的环加成反应

 制备了聚合物负载的季鏻盐催化剂, 并用于 CO₂ 与环氧氯丙烷环加成反应中. 采用红外光谱、热分析、原子吸收光谱和扫描电子显微镜等手段测定了催化剂的结构、热性能、磷元素含量和表面形貌等. 考察了 CO₂ 压力、温度、催化剂用量和反应时间等对环加成反应性能的影响. 结果表明, 在催化剂用量为 0.09 g, CO₂ 压力为 4.5 MPa, 于 150 ^oC 反应 6 h 时, 3-氯甲基环碳酸酯收率可达 97.7%, 选择性大于 99%. 且催化剂易分离回收, 重复使用 5 次后产物收率和选择性没有明显下降. 同时探讨了该催化剂上 CO₂ 环加成合成环碳酸酯的可能机理.

Cycloaddition of CO2 and Epoxides Catalyzed by Polymer-Supported Quaternary Phosphonium Salts

Polymer-supported quaternary phosphonium salts were explored to catalyze the cycloaddition of CO₂ and epoxides. The results indicated that this heterogeneous catalyst possessed high activity and selectivity in the cycloaddition reaction. The catalyst was characterized by thermogravimetric analysis, scanning electron microscopy, and Fourier transform infrared spectroscopy. The influence of CO₂ pressure, reaction temperature, reaction time, and catalyst amount on the cycloaddition reaction was investigated. Excellent yield (97.7%) and high selectivity (> 99%) of cyclic carbonates were achieved under the conditions of p(CO₂) = 4.5 MPa, 150 ^oC, 6 h, and catalyst 0.09 g. The catalyst could be recovered easily and reused several times. A possible reaction mechanism for the cycloaddition of CO₂ and epoxide to cyclic carbonate over the polymer-supported quaternary phosphonium salt was discussed.