Ca掺杂Mg/Al-LDO催化甘油制备碳酸甘油酯

Preparation of Glycerol Carbonate from Glycerol Catalyzed by Ca Doped Mg/Al-LDO

通过共沉淀法制备了钙镁铝类水滑石(Ca/Mg/Al-LDH),并在高温(350~800℃)下煅烧4h得到焙烧态类水滑石催化剂Ca/Mg/Al-LDO,用于催化甘油与碳酸二甲酯(DMC)酯交换反应制备高附加值的碳酸甘油酯(GC)。采用N2吸附-脱附、X射线衍射、扫描电子显微镜和能谱元素分析、红外光谱等对催化剂进行表征分析。探究了催化剂Ca掺杂、煅烧温度及反应条件对反应活性的影响。结果表明,当催化剂中Ca/Mg/Al物质的量比为2∶1∶1,煅烧温度为650℃时,催化剂表现出最好的催化性能。在催化剂用量3%、n(DMC)∶n(甘油)=3、温度75℃、时间为90 min条件下,甘油转化率可达98.3%,GC收率可达96.2%。回收循环实验表明,催化剂在重复使用5次后仍能保持91.9%的甘油转化率和90.5%的GC收率,稳定性优异。

Calcium magnesium aluminum hydrotalcite(Ca/Mg/Al-LDH)is prepared by co-precipitation method and calcined at high temperature(350~800℃)for 4 h to obtain calcined hydrotalcite catalyst Ca/Mg/Al-LDO,which is used to catalyze the transesterification of glycerol with dimethyl carbonate(DMC)to prepare high value-added glycerol carbonate(GC).The catalysts are characterized by N 2 adsorption-desorption,X-Ray diffraction,scanning electron microscopy,energy dispersive spectroscopy and infrared spectroscopy.The effects of Ca doping,calcination temperature and reaction conditions on the reaction activity are investigated.The results show that the catalyst exhibits the best catalytic performance when the molar ratio of Ca/Mg/Al is 2∶1∶1 and the calcination temperature is 650℃.Under the conditions of catalyst dosage of 3%,n(DMC)∶n(glycerol)=3,temperature of 75℃and time of 90 min,the conversion of glycerol can reach 98.3%and the yield of GC can reach 96.2%.The recovery cycle experiment shows that the catalyst can still maintain 91.9%glycerol conversion and 90.5%GC yield after repeats use for 5 times,and the stability is excellent.