Zn-Al水滑石催化碳酸二甲酯与苯酚酯交换反应的研究

用共沉淀法制备了Zn-Al水滑石,并用于多相催化酯交换合成碳酸二苯酯的反应.研究了不同n(Zn)/n(Al)比的水滑石及其焙烧产物等对酯交换反应的催化活性.结果表明,Zn-Al水滑石催化剂对该反应的催化活性和选择性很高,当n(Zn)/n(Al)=3时,在150～180℃,n(PhOH)/n(DMC)=2,催化剂用量为反应物总质量的1.5%,在反应时间为12h的条件下,DMC的转化率达到55.9%,DPC和MPC的收率分别为25.3%和27.0%,酯交换产物的选择性达到93.6%.利用XRD,TG-DTA和TEM等手段对催化剂进行了表征.

Transesterification of Dimethyl Carbonate and Phenol Catalyzed by Zn-Al Hydrotalcite

The Zn-Al hydrotalcite prepared by co-precipitation method was used to catalyze the transesterification of phenol and dimethyl carbonate(DMC). The catalytic activity of Zn-Al hydrotalcite with different molar ratios of Zn to Al and their calcined products were tested. It is found that Zn-Al hydrotalcite has a high catalytic activity and selectivity in the reaction. Under the reaction conditions of n(Zn)/n(Al)=3, n(PhOH)/n(DMC)=2, mass fraction of catalyst =1.5%, t=150180 ℃ and t=12 h, the conversion of DMC reached 55.9%, yield of DPC and MPC was 25.3% and 27% respectively, the selectivity for the transesterificated products was 93.6%. When the hydrotalcite was calcined at 450 ℃ for 8 h, the catalytic activity of them decreased sharply and the XRD patterns indicated that the lamellar structure had already collapsed, which suggested that the specific structure of hydrotalcite is important to catalyze the transesterification. The structure and morphology of Zn-Al hydrotalcite was characterized by XRD and TEM, and the TG-DTA characterization indicated that the structure of Zn-Al hydrotalcite was stable in the range of reaction temperature. The structure and morphology of the catalyst were characterized by XRD, TG-DTA and TEM.