Brφnsted酸性离子液体催化合成油酸甲酯的研究

Synthesis of methyl oleate catalyzed by Brφnsted acid ionic liquids

合成并表征了N-甲基-2-吡咯烷酮硫酸氢盐([Hnmp]HSO4)、N-甲基咪唑硫酸氢盐([Hm im]HSO4)2种阴离子Brφnsted酸性离子液体,考察了这2种离子液体在催化油酸和甲醇酯化反应中的催化活性。结果表明,离子液体的催化活性与其酸性密切相关;当离子液体[Hnmp]HSO4用量为油酸质量的5%,n(甲醇)∶n(油酸)为1.5∶1,反应温度75℃,反应时间3 h时,酯化率可达98%以上。反应结束后离子液体与酯化产物成两相,而且离子液体[Hnmp]HSO4重复使用5次,仍有较高的催化活性。

Two kinds of Brψnsted acid ionic liquids （ [ Hnmp ] HSO4, [ Hmim ] HSO4 ） were synthesized and characterized, the catalytic activities of the acidic ionic liquids for the synthesis of methyl oleate were also investigated. The results showed that the catalytic activity of ionic liquid was closely related to its acidity;under the conditions of molar ratio of methanol to oleic acid 1.5： 1, [ Hnmp ] HSO4 dosage 5 % in the weight of oleic acid,temperature 75℃ and time 3 h, the yield of methyl oleate reached 98% without removal of water during the esterificaion. After reaction, the ionic liquid and esters were separated to two phases in nature. When the ionic liquid of [ Hnmp ] HSO4 was reused 5 times, it still remained a higher catalytic activity.