CaO-TiO_2催化酯交换法合成二甘醇双烯丙基碳酸酯反应

Synthesis of diethylene glycol bis(allyl carbonate) by transesterification over CaO-TiO_2 catalysts

采用(NH_4)_2CO_3溶液、KF溶液及TiO_2和CeO_2氧化物等对CaO催化剂进行改性,考察了制备条件对催化剂性能的影响,优化了二甘醇(DEG)、丙烯醇(AAH)和碳酸二甲酯(DMC)酯交换合成二甘醇双烯丙基碳酸酯(ADC)的反应条件,并考察了催化剂的重复使用性能。采用XRD等方法对CaO-TiO_2催化剂进行表征。实验结果表明,采用机械研磨-焙烧法,以Ca CO3和TiO_2为前体,n(Ca)∶n(Ti)=1,在马弗炉中于空气气氛中900℃下焙烧4 h制备的CaO-TiO_2催化剂对ADC合成反应催化活性最高;酯交换法合成ADC的适宜反应条件为:n(DEG)∶n(DMC)∶n(AAH)=0.08∶1∶2、催化剂含量1.5%(w)、反应温度100℃、反应时间6 h,在此条件下ADC收率最高可达93.6%。表征结果显示,CaO-TiO_2催化剂具有较好的活性和稳定性,Ca Ti O3是CaO-TiO_2催化剂的主活性组分;重复使用5次后,ADC的收率为86.1%。结合表征结果可知,Ca Ti O3是CaO-TiO_2催化剂的主活性组分,CaO的流失是导致催化剂活性略有下降的原因。

（NH4）2CO3 aqueous solution, KF aqueous solution, CeO2 and TiO2 were selected to modify CaO, respectively. The effect of preparation conditions on the catalytic performance of catalyst, the reaction conditions of diethylene glycol bis（allyl carbonate）（ADC） synthesis from diethylene glycol（DEG）, dimethyl carbonate（DMC） and allyl alcohol（AAH）, and the reuseability of catalyst were investigated. CaO-TiO2 catalysts were characterized by XRD. The results showed that CaO-TiO2 was found to have a better catalytic activity and its suitable preparation conditions were as follows： using milling-calcination process, CaCO3 and commercial TiO2 as precursors, n（Ca） ： n（Ti） 1, calcinating at 900 ℃ for 4 h in air. Under the suitable reaction conditions of 100 ℃, 6 h, n（DEG） ： n （DMC） ： n（AAH） 0.08 ： 1 ： 2 and mass percentage of CaO-TiO2 1.5%, the ADC yield reached 93.6%. CaO-TiO2 catalyst possessed good activity and stability, and the ADC yield decreased to 86.1% after the fifth use. The XRD characterization results showed that CaTiO3 is the main active component of CaO-TiO2, and the loss of CaO led to the decline of catalytic activity.