新型碱性离子液体的合成及其在催化制备生物柴油中的应用

Synthesis of a New Basic Ionic Liquid and Its Application in Catalyzing Preparation of Biodiesel

通过两步反应合成了咪唑阴离子型碱性离子液体1-丁基-3-甲基咪唑咪唑盐[Bmim]Im,经1H NMR、13C NMR和FT-IR分析确认了产物结构。利用L9正交表,选取3水平4因素对[Bmim]Im催化大豆油制备生物柴油的催化性能进行正交试验,分别考察了催化剂用量、醇/油摩尔比、反应温度和反应时间对生物柴油产率的影响。结果表明,[Bmim]Im对大豆油与甲醇的酯交换反应具有较高的催化活性,在60℃下,[Bmim]Im用量为原料油的6%时,反应15min后生物柴油产率即可高达94.17%;[Bmim]Im催化制备生物柴油的最佳工艺条件为:催化剂质量分数8%,醇/油摩尔比6,反应时间60min,反应温度60℃,在此条件下,生物柴油的产率可达95.76%。该催化剂稳定性良好,可循环利用。

A new basic ionic liquid paired by 1-butyl-3-methylimidazolium cation and imidazolide anion（Im） was synthesized by a two-step reaction.The sample structure was characterized by 1H NMR、13C NMR and FT-IR.Four factors and three levels were considered without reciprocity,and the orthogonal test table L9 was chosen for the experiment to study the effects of Im in catalyzing the preparation of biodiesel.Reaction conditions,such as the Im catalyst amount,the molar ratio of methanol to oil,the reaction temperature and the reaction time were investigated.The results indicated that this new basic ionic liquid showed high catalytic activity in the preparation of biodiesel by transesterification of soybean oil and methanol.At 60℃,with catalyst amount of 6%（mass fraction）,the yield of biodiesel could reach up to 94.17% in 15 min.The reaction conditions were optimized by means of orthogonal test together with the single-factor test.Under the optimal reaction conditions,i.e,the catalyst amount of 8%（mass fraction）,the methanol to soybean oil molar ratio of 6,the reaction time of 60 min and the reaction temperature of 60℃,the yield of biodiesel could reach 95.76%.The ionic liquid was stable and could be repeatedly used.