介孔载体嫁接的离子液体催化二氧化碳合成碳酸丙烯酯

将离子液体1-丙基(三乙氧基硅基)-3-甲基咪唑的氢氧化物([Smim]OH)分别嫁接到介孔SiO_2、MCM-41和SBA-15分子筛上制备了非均相嫁接型离子液体,用傅里叶变换红外光谱、N_2吸附、元素分析和热重分析等技术对3种非均相嫁接型离子液体进行了表征。在无溶剂、温和的条件下,以非均相嫁接型离子液体为催化剂,研究了环氧丙烷(PO)与CO_2环加成合成碳酸丙烯酯的反应。实验结果表明,3种非均相嫁接型离子液体均具有较好的催化性能,[Smim]OH/SiO_2的催化性能最好;在[Smim]OH/SiO_2 1.260 mmol、PO 70 mmol、CO_22 MPa、120℃、8 h的优化反应条件下,PO的转化率可达99.5%;[Smim]OH/SiO_2重复使用4次后仍能保持较高的催化性能。

Synthesis of Propylene Carbonate from Carbon Dioxide Catalyzed by Ionic Liquid Grafted on Mesoporous Supports

Ionic liquid, 1-propyl(triethoxysilyl)-3-methylimidazolium hydroxide([Smim]OH) was grafted onto three selected mesoporous supports, namely SiO_2, MCM-41 and SBA-15 molecular sieve, to prepare heterogeneously grafted ionic liquids which was used as catalysts for synthesis of propylene carbonate(PC) from propylene oxide(PO) and CO_2 by cycloaddition. The obtained heterogeneously grafted ionic liquids were characterized by means of FTIR, N2 adsorption, elemental analysis and TG, which were effective catalysts in the cycloaddition. The reaction conditions were mild without any solvent. Among the three supported catalysts, [Smim]OH/SiO_2 exhibited the best catalytic performance. Under optimal reaction conditions: [Smim]OH/SiO_2 1.260 mmol, PO 70 mmol, CO_2 2 MPa,120 ℃ and 8 h, conversion of PO reached 99.5% and selectivity to PC approached 100%. Catalytic activity of [Smim]OH/SiO_2 basically remained after being reused 4 times.