Mg-Al类水滑石催化大豆油酯交换制备生物柴油

The production of biodiesel via transesterification of soybean oil over Mg-Al hydrotalcite catalyst

采用共沉淀法制备了不同n(Mg)/n(Al)比的Mg-Al类水滑石,在不同温度下焙烧得到复合氧化物,作为大豆油与甲醇反应制备生物柴油的催化剂。结果表明,未焙烧Mg-Al类水滑石的催化活性较差,而n(Mg)/n(Al)=3的类水滑石在450℃焙烧时具有极高的催化活性。在反应温度65℃,醇/油15,催化剂用量为大豆油质量的2%,反应3 h,生物柴油产率可达97.4%。催化剂回收再用性能良好,重复使用3次,生物柴油收率仍在90%左右。

A series of Mg-Al hydrotalcite compouds with different n（Mg）/n（Al） ratio were prepared via co-precipitation process and calcined at different temperatures to give their derivatives,Mg-Al composite oxides solid alkali catalysts,which were applied in the producation of biodiesel via the transesterification of soybean oil and methanol.It was found that the Mg-Al hydrotalcite without calcination showed lower activity,while a sample with n（Mg）/n（Al）=3 calcined at 450 ℃ gave the best catalytic performance.Under the following conditions：2% catalyst,methanol/soybean molar ratio 15,reacting at 65 ℃ for 3 h,the highest yield（97.4%） of biodiesel was acquired.Moreover,the catalyst could be recovered and maintained good yield for three reused times.