室温离子液体催化合成碳酸丙烯酯

碳酸丙烯酯(PC)是一种性能优良的高沸点高极性有机溶剂,在有机合成、化妆品、气体分离、电池介电质1]及金属萃取2]等领域得到广泛的应用. 近年来,许多尿素生产厂家将其用作脱碳剂,使其需求量大增. PC合成方法主要有光气法、酯交换法、氯丙醇法及环氧丙烷(PO)与CO2环加成等. 其中, 以PO与CO2为原料环加成制PC是一条低污染、环境友好的路线. 已报道的用于PO与CO2环加成的催化剂有碱、季铵盐、金属盐3]、配合物4～6]以及MgO7], MgO-Al2O38], KI/ZnO9],KI/冠醚和KI/聚乙二醇10]等. 尽管品种繁多,但仍存在催化剂活性不高,产物分离及催化剂回收困难等问题.

Formation of Propylene Carbonate Catalyzed byRoom Temperature Ionic Liquids

In the presence of room temperature ionic liquids based on 1 butyl 3 methylimidazolium salt and butylpyridinium salt, cycloaddition of propylene oxide and carbon dioxide without any additional organic solvents was investigated. It was found that both cations and anions of the room temperature ionic liquids have strong influence on the catalytic activity. The better catalytic performance was achieved with 1 butyl 3 methylimidazolium tetrafluoroborate as a catalyst. A suitable CO 2/propylene oxide molar ratio is needed for the reaction, and the conversion of propylene oxide increases with the increase of reaction temperature. The ionic liquid as a catalyst for such reaction can be recycled.