Al-MCM-41负载离子液体双酸位催化剂及制备生物柴油

Al-MCM-41 Immobilized Ionic Liquids Catalysts Containing Double-Acid Active Sites for Biodiesel Production

采用不同硅铝比的MCM-41负载离子液体,制备得到一系列负载型双酸位催化剂,并用XRD、FTIR、N2-吸脱附、热重分析及TEM对其进行表征,以大豆油与甲醇的酯交换反应为探针实验考察了其催化活性。结果表明,离子液体成功固载于介孔分子筛并能保持其介孔结构,且在酯交换反应中表现出良好的反应活性。在ILs负载量为30%,醇油物质的量的比为36∶1,140℃下反应5 h,生物柴油收率在90%以上;而分子筛中Al的引入为活性组分离子液体构建了有益的酸环境,促进了其催化活性的提高;与均相离子液体相比,负载型催化剂又能明显提高生物柴油的收率,且回收利用4次后,生物柴油收率仍接近88%。

The immobilized catalysts with double-acid active sites were synthesized by loading ionic liquids（ILs）on MCM-41 with different Si/Al molar ratios. The catalysts were characterized by XRD, FTIR, N2 adsorptiondesorption, thermogravimetric analysis and TEM, and the activities of catalysts were investigated by the transesterification of soybean oil with methanol for biodiesel synthesis as the probe reaction. The results demonstrated that the ionic liquids were successfully immobilized on the mesoporous molecular sieves. The catalysts could maintain their mesoporous structure and showed good catalytic performance in transesterification.The biodiesel yield was more than 90% under the condition of 30% ILs-loading, methanol to oil molar ratio of36∶1 and temperature at 140 ℃ for 5 h. The beneficial acid environment was created for the active component ILs by introducing Al to MCM-41, which greatly improved the catalytic performance of ILs. The ILs immobilized catalysts exhibited much higher activities in transesterification than the homogeneous ILs, and the ILs immobilized catalyst still yielded about 88% after four cycles.