哌嗪型双核酸性离子液体催化合成苯甲酸甲酯  

Study on the synthesis of methyl benzoate from benzoic acid catalyzed by dual-core piperazine-based ionic liquids

作　　者：李祥 尹慧 旷宇阳 刘宁 Xiang Li;Hui Yin;Yuyang Kuang;Ning Liu(School of Chemical and Environmental Engineering,Hunan Institute of Technology,Hengyang,Hunan 421002,China)

机构地区：[1]湖南工学院化学与环境工程学院,湖南衡阳421002

出　　处：《日用化学工业（中英文）》2024年第5期514-519,共6页China Surfactant Detergent & Cosmetics

基　　金：湖南省教育厅科学研究项目重点项目(22A0628);湖南省自然科学基金青年项目(2020JJ5117);湖南省大学生创新创业训练计划项目(S202311528069,S202211528057)。

摘　　要：以1,4-二甲基哌嗪为原料,通过与1,3-丙磺酸内酯加成反应合成中间体,再进一步分别与对甲苯磺酸、浓硫酸(H_(2)SO_(4))、甲烷磺酸等质子酸发生离子交换等反应,最终合成一系列磺酸功能化哌嗪类离子液体,其中1,4-双[N-甲基-N-(3-磺丙基)]哌嗪对甲苯磺酸盐([BMSP][PSA])在苯甲酸-甲醇酯化反应中显示出相对较优的催化活性,并通过FT-IR,^(1)H-NMR和TGA-DTG对其的结构与性能进行表征,确定了所合成的离子液体结构,且其具有较好的耐热性。结果表明:在醇酸摩尔比为16∶1、反应温度为70℃、反应时间为3 h、[BMSP][PSA]用量为3 mmol的条件下,苯甲酸转化率达到最大值97.6%,且在重复使用催化剂5次后,苯甲酸转化率仍然可达93.9%,显示了优异的催化活性,是一种可应用于工业化生产苯甲酸甲酯的绿色催化剂。Benzoates are important intermediates for preparing perfume essence and artificial essential oils.For conventional esterification of benzoic acid with methanol,protonic acids such as HCl,H_(2)SO_(4),have been used,which is harmful to equipment and shows low product yield.Using ionic liquids as solvents or catalysts can make the reaction conditions stable,recyclable,and environment-friendly,and lead to high product yield.In this work,a series of sulfonicacid-functionalized dual-core piperazine-based ionic liquids,such as 1,4-bis[N-methyl-N-(3-sulfopropyl)]piperazine bis(p-toluenesulfonate)([BMSP][PSA]),1,4-bis[N-methyl-N-(3-sulfopropyl)]piperazine dimethanesulfonate([BMSP][MSA]),and 1,4-bis[N-methyl-N-(3-sulfopropyl)]piperazine bis(hydrosulfate)([BMSP][SA]),were synthesized by a two-step process.The molecular structure of[BMSP][PSA]was characterized by FT-IR,^(1)H NMR and TGA-DTG.It exhibited good thermal stability.The results showed that the three sulfonic-acid-functionalized dual-core piperazine-based ionic liquids had excellent catalytic activity,among which the synthesized[BMSP][PSA]exhibited the best catalytic activity.The conversion of benzoic acid reached 97.6%under the conditions of alcohol-acid ratio of 16∶1,reaction temperature of 70℃,reaction time of 3 h,and catalyst dosage of 3 mmol.The conversion for esterification still reached 93.9%after 4 cycles with the catalyst,which showed excellent catalytic activity.Therefore,it was a good candidate of green catalyst for industrial production.

关 键 词：离子液体 酯化反应 苯甲酸甲酯 1 4-二甲基哌嗪 

分 类 号：TQ658[化学工程—精细化工]