K_2CO_3/γ-Al_2O_3催化菜籽油酯交换合成生物柴油

采用等体积浸渍法制备了负载型固体碱K2CO3/γ-Al2O3催化剂,并将其用于催化菜籽油与甲醇酯交换反应合成生物柴油。考察了催化剂制备条件和反应条件对生物柴油收率的影响。实验结果表明,采用K2CO3负载量(质量分数)为20%、在600℃下焙烧5h的K2CO3/γ-Al2O3催化剂,当催化剂与菜籽油的质量比为0.03,甲醇与菜籽油的摩尔比为12∶1,在60℃下反应1h后,生物柴油的收率高达93.6%。用X射线衍射、比表面积测定等手段对催化剂的结构进行了表征,表征结果显示,催化剂的活性与其晶相和比表面积密切相关。

Synthesis of Biodiesel- Oil from Rapeseed Oil by Transesterification over K2CO3/γ- Al2O3 Catalyst

Synthesis of biodiesel oil by transesterification of rapeseed oil and methanol over K2CO3/γ-Al2O3 solid base catalyst was studied. The K2CO3/γ-Al2O3 catalyst was prepared by isochoric impregnation. Effects of K2CO3 loading, catalyst calcination temperature, catalyst dosage, mole ratio of methanol to rapeseed oil, reaction temperature and time on the transesterification were investigated. Under optimal conditions: K2CO3 loading 20% (mass fraction),catalyst calcined at 600 ℃ for 5 h,mole ratio of methanol to rapeseed oil 12 ∶1, mass ratio of catalyst to rapeseed oil 0.03,reaction temperature 60 ℃ and time 1 h, yield of synthesized biodiesel oil can reach 93.6%. The support,fresh and used catalysts were characterized by means of XRD and BET. The catalytic activity is closely related with its specific surface area and formation of new crystalline phase due to interaction between K2CO3 and γ-Al2O3 during calcination.