新型生物炭基催化剂催化甘油合成碳酸甘油酯

Biochar supported catalyst for transesterification reaction of glycerol to glycerol carbonate

以固体废弃物核桃壳生物炭为原料,制备了一系列廉价、高效的固体碱复合催化剂,并应用于甘油和碳酸二甲酯的酯交换反应试验.催化剂通过扫描电子显微镜、X射线能谱、X射线衍射、N2吸脱附、傅里叶变换红外光谱及Hammett指示法进行表征;同时对催化剂的制备条件、催化反应条件及重复利用进行了分析.试验结果表明：催化剂30K/WB-600展示了最优的催化活性,当反应中催化剂的质量分数为5%、碳酸二甲酯/甘油摩尔比为4：1、反应时间为90 min、反应温度为80℃时,甘油的转换率达到98.3%,甘油碳酸酯的产率达到94.6%;经过5次循环利用后甘油转换率为94.2%,甘油碳酸酯产率为85.2%;催化剂的失活主要是由于少量K离子的流失.

The walnut shell was utilized as the raw material for the preparation of cost-effective and high-efficiency solid base catalysts for the transesterification reaction of glycerol with dimethyl carbonate.The chemical and structural properties of catalysts were examined by scanning electron microscope（SEM）,energy dispersive spectrometer（EDS）, X-ray diffraction（XRD）, N2 adsorption/desorption,Fourier-transform infrared spectroscopy（FTIR） and the Hammett indicator method.In addition,the effects of catalyst preparation conditions,reaction conditions and the catalyst reusability were studied.Experiment results show that the best performance is observed for the resulting 30 K/WB-600 catalyst,with the catalyst mass fraction of 5%,DMC/glycerol molar ratio of 4：1,reaction time of 90 min and reaction temperature of 80 ℃,the conversion of glycerol and yield of GC attain 98.3% and 94.6%,respectively.After 5 repeated uses,the conversion of glycerol and yield of GC were 94.2% and 89.8%,respectively. The deactivation of catalyst is mainly due to the leaching of K＋ ions.