温和条件下电催化CO2与环氧丙烷合成碳酸丙烯酯

 在常温常压下研究了CO2的电化学活化及其与环氧丙烷反应合成碳酸丙烯酯,考察了支持电解质对碳酸丙烯酯产率的影响. 结果表明,含有Br-的支持电解质对合成碳酸丙烯酯起到明显的催化效果. 在实验研究基础上,对反应机理进行了初步推测,认为Mg2+起到路易斯酸的作用并与环氧丙烷的氧原子配位,同时Br-作为亲核试剂进攻环氧丙烷的 C-O 键使其断裂开环,形成的中间物与CO2还原产生的活化物质结合形成碳酸丙烯酯.

Electrocatalytic Synthesis of Propylene Carbonate from CO2 and Propylene Oxide under Mild Conditions

The electroreduction of CO2 and electrocatalytic synthesis of propylene carbonate (PC) were studied in dimethylformamide (DMF) solvent under mild conditions (p(CO2)=101 kPa, room temperature). CO2 can be electroreduced in DMF-0.1 mol/L tetraethylammonium bromide by cyclic voltammetry. An irreversible one-electron reduction peak of CO2 appeared at -2.1 V vs Ag, indicating that an activated species may be generated. The electrocatalytic synthesis of propylene carbonate from CO2 and propylene oxide in DMF was studied using six different supporting electrolytes. The results showed that supporting electrolytes including Br- acted as both a supporting electrolyte and a catalyst to synthesize propylene carbonate. The selectivity for propylene carbonate was 100%. A proposed mechanism involved the opening of the epoxide ring through a nucleophilic attack by Br-and Mg2 , which formed an intermediate affording propylene carbonate after reaction with the activated CO2.