丙烯酸甲酯改性氧化钙催化制备生物柴油的研究

Study of biodiesel production catalyzed by modified CaO with methacrylate

以丙烯酸甲酯为改性剂,对氧化钙表面进行改性,研究丙烯酸甲酯改性氧化钙催化油脂-甲醇酯交换体系制备生物柴油性能的影响。考察了改性剂用量、醇油摩尔比以及催化剂用量对体系酯化率的影响,并对催化剂进行表征。结果表明,表面改性后,氧化钙的催化性能得到极大改善。在反应温度为65℃、丙烯酸甲酯改性剂用量为0.5%、醇油摩尔比为20∶1、催化剂用量为15%、反应时间2 h条件下,生物柴油产率高达96.55%,与未改性氧化钙相比,相同条件下生物柴油产率提高16.18%。同时,丙烯酸甲酯改性氧化钙还具有良好的耐水性能,在体系含水量1%条件下催化制备生物柴油产率仍能达到81%。催化剂BET表征结果显示,改性后氧化钙较改性前的比表面积、平均孔径和孔体积均增大;热重表征结果表明,氧化钙改性后热稳定性提高,颗粒分散性增强;XRD、FTIR表征显示,丙烯酸甲酯改性剂已经成功键合到氧化钙表面。

Commercial CaO was modified with methacrylate and the catalytic performance for transesterification of methanol and rapeseed oil to biodiesel production has been investigated. The influences of modifier dosage,molar ratio of rapeseed oil to methanol and catalyst on the esterification rate of system were investigated,and the catalyst were characterized. It was found that the reaction efficiency over modified CaO has been greatly improved and the high biodiesel yield of 96. 55% can be obtained over 0. 5% methacrylate modified CaO at 65 ℃,20∶ 1 molar ratio of rapeseed oil to methanol,the amount of catalyst was 15%after 2 h,which was 16. 18% higher than the yield over commercial CaO. Moreover,good water resistance has been found over the modified CaO and 81% biodiesel yield still remained even 1% water has been added. Catalyst BET characterization shows,it can be seen that the specific surface area,average pore diameter and pore volume have been increased after modifying; From the TG characterization results,it can be seen that the surface properties,thermal stability and particle dispersion have also been changed after modifying. XRD and FITR shows,methacrylate modified agent has successfully bonded to the surface of CaO.