高酸值花椒籽油制备生物柴油的研究

摘要

采用两步法催化花椒籽油制备出了生物柴油：第一步，利用炭基固体酸催化剂催化花椒籽油与甲醇进行酯化反应来降低游离脂肪酸（Free Fatty Acids ，FFA）的含量，以单因素实验考察了醇油摩尔比、反应时间、反应温度、催化剂用量等因素对酯化反应的影响，并通过正交试验确定了最佳工艺条件；第二步，利用氢氧化钾催化甘油三酯与甲醇发生酯交换反应，采用1 H NMR表征并计算得到了生物柴油的产率．结果表明：在酯化反应阶段，醇油摩尔比30∶1、催化剂用量为油重的12％、温度60℃、时间4．5 h等为最佳反应条件，在此条件下，花椒籽油的酸值由73．75 mg KOH／g降到1．76 mg KOH／g（FFA＜1％），满足后期酯交换反应条件；在酯交换反应阶段，氢氧化钾酯交换反应制备的生物柴油中脂肪酸甲酯的产率为99．74％．%Two-step process for the preparation of biodiesel from z anthoxylum bungeanum seed oil (ZSO) was adopted .In the first step ,the esterification process was required to re-duce the amount of FFA in the feedstock catalyzed by the carbon-based solid acid catalyst . The variables affecting esterification reaction including methanol-to-oil molar ratio ,catalyst amount ,reaction temperature ,reaction time were investigated and the optimum conditions for the esterification reaction were obtained by the orthogonal experiment .In the second step ,transesterification was catalyzed between triglycerides and methanol using potassium hydroxide as catalyst .The yield of biodiesel was confirmed by 1 H NMR .The results showed that the optimal conditions were methanol-to-oil molar ratio 30∶1 ,catalyst loading amount 12% ,reaction temperature 60 ℃ and reaction time 4 .5 h in the esterification stage and under this condition ,the acid value of ZSO was reduced to 1 .76 mg KOH/g from 73 .75 mg KOH/g ,w hich satisfied the treatment of alkali-catalyzed transesterification for biodiesel produc-tion .In the transesterification stage ,the yield of fatty acid methyl ester prepared by KOH-catalyzed transesterification was 99 .74% .