磺酸功能化离子液体催化甘油与甲醇醚化反应

考察了[HSO₃-bmim]CF₃SO₃、[HSO₃-bmim]P-TSA、[HSO₃-bmim]HSO₄和[HSO₃-bmim]H₂PO₄四种磺酸功能化离子液体对甘油与甲醇醚化反应的影响。结果表明,离子液体的催化性能与其酸强度相关联,[HSO₃-bmim]CF₃SO₃离子液体的酸强度最强,其催化性能也最好。以[HSO₃-bmim]CF₃SO₃为催化剂,在w([HSO₃-bmim]CF₃SO₃)/w(甘油)=0.5:1(质量比)、n(甲醇)/n(甘油)=8:1(摩尔比)、反应温度190℃、反应时间8 h时,甘油的转化率为84.5%,单甲基甘油醚的选择性为41.4%,二甲基甘油醚和三甲基甘油醚的联合选择性为34.1%。在此基础上,提出了离子液体[HSO₃-bmim]CF₃SO₃催化甘油与甲醇醚化反应的反应机理。

Etherification of glycerol with methanol catalyzed by SO3H-functioned ionic liquids

The catalytic performance of some SO₃H-functionalized ionic liquids ([HSO₃-bmim]CF₃SO₃,[HSO₃-bmim]P-TSA,[HSO₃-bmim]HSO₄ and [HSO₃-bmim]H₂PO₄) in the etherification of glycerol with methanol was evaluated,and the results showed that the catalytic performance of the ionic liquids correlated well with their acid strength.[HSO₃-bmim]CF₃SO₃ had the highest acid strength and showed the best catalytic performance.Under the suitable reaction conditions of mass ratio of [HSO₃-bmim]CF₃SO₃ to glycerol 0.5:1, molar ratio of methanol to glycerol 8:1, reaction temperature 190℃ and reaction time 8 h, conversion of glycerol was 84.5%, selectivity to methyl glycerol ethers and total selectivity to both dimethyl glycerol ethers and trimethyl glycerol ethers were 41.4% and 34.1%, respectively.In addition, the reaction mechanism for etherification of glycerol with methanol in the presence of[HSO₃-bmim]CF₃SO₃ was proposed.