硫酸氢铵盐离子液体催化亚麻油制备生物柴油的研究

摘要

以浓硫酸和三乙胺为原料制备了酸性离子液体硫酸氢铵盐[Et3NH][HSO4],作为催化剂用于亚麻油与甲醇酯交换反应制备生物柴油.考察了催化剂添加量、醇油摩尔比、反应温度和反应时间等因素对酯交换产品收率的影响.试验结果表明:硫酸氢铵盐离子液体对酯交换反应有很高的催化活性,在甲醇与亚麻油摩尔比为8:1、催化剂占原料油质量分数6%、反应温度120 ℃和反应时间5 h的优化条件下,酯交换产品收率可达90%以上.产物中含有十五酸甲酯、软脂酸甲酯等长链酯类物质,与生物柴油的化学组成分相似,说明离子液体硫酸氢铵盐能够催化制备生物柴油.%Ammonium hydrogen sulfate acidic ionic liquid[Et3NH][HSO4] is prepared by concentrated sulfuric acid and trieth-ylamine,and is used as catalyst to catalyze the transesterification of linseed oil and methanol to synthesize biodiesel. The effects of cat-alyst additive amount,molar ratio of methanol and linseed oil,reaction temperature and time on the product yield are investigated. The results show that ammonium hydrogen sulfate ionic liquid displays high catalytic activity on the transesterification,and under the opti-mum conditions of molar ratio of methanol and linseed oil 8:1,catalyst accounting for 6% of raw oil amount in mass fraction,tempera-ture of 120 ℃ and time of 5 h, the product yield of transesterification can reach up to 90%. The products contain long chain esters such as pentadecylic acid methyl ester, palmitic acid methyl ester and so on, which has similar chemical composition of biodiesel, which indicates the ammonium hydrogen sulfate ionic liquid can be used as catalyst in preparing biodiesel.