A series of organic anion-pillared hydrotalcites were synthesized by the ion exchange method and characterized by X-ray diffraction and Fourier transform infrared spectroscopy.The hydrotalcite precursor and pillared hydrotalcites with different anions was tested as catalysts in transesterification of dimethyl carbonate（DMC） with phenol.The results show that the catalytic selectivity of this transesterification reaction over these organic anion-pillared hydrotalcites is significantly improved.The catalytic selectivities of C4H4O4-,C6H8O4-,C10H16O4-,（1,4-）C8H4O4-,and C7H5O2-pillared hydrotalcites for transesterified products（diphenyl carbonate and methyl phenyl carbonate） are all greater than 90%,at least 10% higher than that of the hydrotalcite precursor.Under the conditions of（n（phenol））/（n（DMC））=4,catalyst amount=1.5%,and t=10 h,the C6H8O4-pillared hydrotalcite presents the best catalytic performance,and the DMC conversion and the selectivity for transesterified products reach 43.8% and 93.2%,respectively.
Hybrid mesoporous silica MCM-41 (O-MCM-41) was prepared using γ-aminopropyltriethoxysilane (APTES) as spacer, tetraethoxysilane as precursor and 2-acetylpyridine as organic moiety. The heterogeneous palladium catalyst (PdCl2 / O-MCM-41) was then prepared by reaction of the hybrid MCM-41 with PdCl2(PhCN)2. The products were characterized by means of IR, XRD, XPS and N2 adsorption-desorption isotherms. The catalytic properties of the supported catalyst in the oxidative carbonylation of phenol to diphenyl carbonate (DPC) were investigated. The yield of DPC and turnover number (TON) reached 5.8% and 29 mol DPC·mol Pd-1, and Pd loss was only 2.7% at 110 °C, 4.4 MPa for catalytic reaction of 5 h with 4.2wt% Pd loading, and molar ratio of phenol to Pd being 1000 in the presence of Cu2O and terahydrofuran (THF).
