1-甲基咪唑醋酸离子液体催化合成甲基丙烯醛

合成了1-甲基咪唑醋酸（Mim]Ac）质子型离子液体,对其进行了1H NMR和IR表征。以Mim]Ac为催化剂，甲醛、丙醛、二乙胺为原料，通过Mannich反应制备了甲基丙烯醛。考察了原料投料比、Mim]Ac用量、Mannich反应温度和反应时间等因素对甲基丙烯醛收率的影响。研究结果表明，当甲醛、丙醛和二乙胺的摩尔比为1.1：1.0：1.0，Mim]Ac用量（物质的量）为丙醛的10.0%，Mannich反应温度为45℃，反应时间为50 min，分解反应温度为75℃，甲基丙烯醛的收率为95.3%，并对产物进行了1H NMR表征。同时，对Mim]Ac质子型离子液体催化Mannich反应的机理进行了初步研究。

Synthesis of Methacrolein Catalyzed by 1-Methylimidazolium Acetate Ionic Liquid

1-Methylimidazolium acetate （Mim]Ac） protic ionic liquid was prepared, and its structure was confirmed by 1H NMR and IR. Methacrolein was prepared through Mannich reaction of formaldehyde, propionaldehyde, and diethyl amine with Mim]Ac as the catalyst. The influences of molar ratio of reactants, amount of catalyst, Mannich reaction temperature and reaction time were investigated. The proper reaction conditions were as follows： the molar ratio of formaldehyde to propionaldehyde to diethyl amine was 1.1：1.0：1.0, amount of Mim]Ac was 10.0% （relative to propionaldehyde）, Mannich reaction temperature was 45 ℃, reaction time was 50 min, decomposition temperature was 75 ℃, the yield of methacrolein was 95.3%. The structure of methacrolein was confirmed by 1H NMR. A preliminary study was carried out on the Mannich reaction mechanism catalyzed by Mim]Ac.