Abstract: 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.

Key words: Zn-Al hydrotalcite, Transesterification, Dimethyl carbonate, Methyl phenyl carbonate, Diphenyl carbonate