硅胶固载磺酸功能化离子液体催化棕榈酸制备生物柴油的工艺研究

以硅胶固载N,N-二甲基苄胺丙基磺酸基硫酸氢盐离子液体(DMBPSH]HSO_4/SG)为催化剂,进行棕榈酸与甲醇酯化制备生物柴油工艺研究,考察了醇酸摩尔比、催化剂用量、反应时间及反应温度等因素对棕榈酸甲酯收率的影响。研究表明,10%DMBPSH]HSO_4/SG催化剂具有最好的催化酯化活性;以10%DMBPSH]HSO_4/SG为催化剂,利用响应面分析法优化生物柴油的最佳制备工艺条件为:醇酸摩尔比12.6∶1,催化剂用量为棕榈酸质量的5.3%,反应时间2.3 h,温度368 K,此条件下,棕榈酸甲酯的收率为97.2%,该结果与模型预测值基本相符。最佳条件下,棕榈酸甲酯合成反应的活化能为15.89 kJ/mol,动力学方程为:■。

Catalytic Synthesis of Biodiesel from Palmitic Acid using Silica Gel-Based Sulfonic Acid Functionalized Ionic Liquid as Catalysts

Methyl palmitate was synthesized by the esterification of palmitic acid and methanol with N,N-dimethyl(benzyl)ammonium propyl sulfobetaine hydrosulfate embedded silica gel (DMBPSH]HSO4/SG) as catalyst. The effects of alcohol/acid molar ratio, catalyst amount, reaction time and reaction temperature were also investigated. The 10%DMBPSH]HSO4/SG catalyst was found to exhibit superior performance during synthetic process. Moreover, an experimental design was exploited via response surface methodology (RSM) for the optimization of process variables. Accordingly, the reaction conditions were optimized as follows: methanol/palmitic acid molar ratio of 12.6:1, catalyst amount of 5.3 wt% and reaction time of 2.3 h at a temperature of 368 K, which contributed to a maximum methyl palmitate yield of 97.2%. These values were in close agreement with the mathematical model. Under optimized conditions, the active energy was 15.89 kJ/mol, and the kinetic equation can be expressed as .