乙酸盐上二氧化碳和二醇合成环状碳酸酯

在乙腈体系中,以不同的乙酸盐作催化剂,研究了CO2与二醇合成环状碳酸酯的反应.乙腈在反应过程中不仅是溶剂,而且还起到了脱水剂的作用,促进了反应的进行.以1,2-丙二醇为反应物对催化剂进行筛选,发现无水乙酸锌具有最高的催化活性.在无水乙酸锌上考察了二氧化碳和不同二醇的反应,结果表明,五元环碳酸酯的产率明显高于六元环碳酸酯,其中碳酸丙烯酯的产率最高.以1,2-丙二醇为反应基质,无水乙酸锌为催化剂,确定了最佳反应条件,1,2-丙二醇100 mmol,乙睛10 mL,催化剂2.5 mmol,反应压力10 MPa,温度170 ℃,反应12 h.在此条件下,碳酸丙烯酯的产率达到了24.2%,1,2-丙二醇的转化率为38.9%.

Synthesis of cyclic carbonate from carbon dioxide and diols over metal acetates

Different metallic acetates were used as the catalysts to synthesize cyclic carbonates from carbon dioxide and diols in the presence of acetonitrile. In the course of reaction, acetonitrile acted as not only the solvent but also the dehydrating reagent to eliminate the effect of the water produced from the reaction. Thus, the thermodynamic equilibrium was shifted and the yield of cyclic carbonates was improved. Using 1,2-propylene glycol as the reactant to screen the catalysts, it was found that anhydrous zinc acetate possessed the highest catalytic activity. The reaction of carbon dioxide and diols was systemically studied over anhydrous zinc acetate. The results showed that the yields of five-membered cyclic carbonates were obviously higher than that of six-membered cyclic carbonates and the yield of 1,2-propylene carbonate was the highest. Using 1,2-propylene glycol as the reactant and anhydrous zinc acetate as the catalyst, the reaction conditions were optimized as 1,2-propylene glycol 100 mmol, acetonitrile 10 mL, catalyst 2.5 mmol, reaction pressure 10 MPa, reaction temperature 170°C, and reaction time 12 h. Under the optimal conditions, the yield of 1,2-propylene carbonate was 24.2% and the conversion of 1,2-propylene glycol was 38.9%.