SiO_2担载壳聚糖负载钯对有机锡试剂和α-卤代酸酯偶联反应的催化作用

Catalytic Performance of Silica-supported Chitosan-Pd (Ⅱ) in Coupling Reaction of Organotins and α-Halogenated Acid Ester

用SiO2担载壳聚糖(CS),再与PdCl2配位,制得催化剂SiO2-CS-PdCl2,详细考察了催化剂对有机锡试剂和α-卤代酸酯交叉偶联反应的催化作用及使用寿命。结果表明该天然高分子负载型钯催化剂对偶联反应具有较高的催化活性和化学选择性,分离容易,可以重复使用,酯基在反应中不被破坏。催化剂循环使用6次,偶联反应产率仍在40%以上。采用XPS分析方法对催化剂进行了表征,证明催化活性中心是金属态钯,并对反应机理进行了研究和探讨。

A silica-supported chitosan-palladium complex SiO_2CS-PdCl_2 with good activity and chemical selectivity for the coupling reaction of Organotins and α-halogenated acid ester was prepared in this lab.The catalyst could be separated easily from the produce system and reuse for many times.The ester groups would not be destroyed in the reaction and the yield still reached 40% after it was used many times.The catalyst was characterized with XPS method.The experimental results showed that the metallic Pd was the active center.The catalytic mechanism was also studied and discussed in this paper.