负载型固体碱催化棕榈油酯交换制备生物柴油

Synthesis of Biodiesel from Palm Oil by Transesterification on Supported Solid Base Catalysts

采用浸渍法制备了KF/CaO,K2CO3/CaO,KF/γ-Al2O3,K2CO3/γ-Al2O34种负载型固体碱催化剂。考察了催化剂种类对棕榈油与甲醇进行酯交换反应的影响,并研究了催化剂重复使用的可能性。实验结果表明,4种催化剂均具有较高的活性,在催化剂中活性组分负载量为20.0%(相对于载体的质量分数)、n(甲醇):n(棕榈油)=12、m(催化剂):m(棕榈油)=0.09、反应温度65℃、反应时间6h的条件下,生物柴油的收率依次为97.3%,93.4%,77.7%,96.2%。以CaO为载体的催化剂再生后活性较低,而以γ-Al2O3为载体的催化剂再生后活性较高。X射线衍射和热重-差热分析结果显示,催化剂活性的差异与煅烧过程中活性组分和载体相互作用形成的新晶相有关,再生后催化活性的降低是由于活性组分流失所致。

Biodiesel was synthesized by transesterification of palm oil with methanol on four kinds of solid base catalysts （KF/CaO,K2CO3/CaO,KF/γ-Al2O3,K2CO3/γ-Al2O3 ） prepared by impregnation. The influences of catalyst species on transesterification and reuse of catalysts were focused on in the study. When mole ratio of methanol to palm oil 12, mass ratio of catalyst to palm oil 0.09, reaction temperature 65℃ and reaction time 6 h, yield of biodiesel on the above four catalysts were about 97.3%, 93.4%, 77.7% and 96.2%, respectively. The results of XRD and TG-DTG showed that the differences in activity of the four catalysts ascribed to formation of some different new crystal phase by interaction of active components with supports during calcination. After regeneration the extents of lowering activity of the catalysts supported on γ-Al2O3 were obviously less than those of catalysts supported on CaO. The fact was mainly due to significant loss of active component of the latter during transesterification.