二氧化硅负载甲烷磺酸催化酯交换制备生物柴油

Synthesis of biodiesel via transesterification over silica-supported methanesulfonic acid

通过溶胶-凝胶-包埋法制备的二氧化硅负载甲烷磺酸固体酸催化剂,用于大豆油与乙醇的酯交换制备生物柴油,考察了催化剂的处理温度、乙醇与大豆油物质的量比、催化剂用量、正庚烷用量和反应时间的影响。结果表明,二氧化硅负载的甲烷磺酸具有较高的酯交换反应活性。制备生物柴油的最佳条件为:催化剂焙烧温度130 ℃、醇油物质的量比6:1、催化剂用量为大豆油质量的5.0%,溶剂正庚烷用量为大豆油质量的30.0%,反应时间6 h。在此条件下,产品收率可达98.33%。与固体碱催化剂相比,固体酸催化剂对原料的酸度有更强的适应性。

Biodiese were synthesized via transesterification of soybean oil with ethanol in the presence of solid acids as the heterogeneous catalyst. Silica-supported methanesulfonic acid（CH3SO3H-SiO2 ） was pre- pared by sol-gel method as the catalyst. Effects of treatment temperature for the catalyst, n （ethanol） ： n（ soybean oil）, dosage of the catalyst, dosage of heptane and reaction time were investigated. The results showed that the silica-supported methanesulfonic acid （CH3SO3H-SiO2 ） catalysts exhibited high activity for the transesterification. Biodiesel yield of 98.33% was obtained under optimum condition as follows： catalyst being treated at 130℃, n（ethanol）：n （soybean oil） = 6： 1, mass fraction of the catalyst in soy- bean oil = 5.0% , mass fraction of heptane in soybean oil = 30.0%, reflux time 6 h. The solid acid cata- lysts have better adaptability to the feeds than solid base catalysts.