Abstract: The Pd/MgO, Pd/Al2O3, and Pd/HT catalysts with 0.5% Pd contents were prepared by the impregnation method using MgO,γ-Al2O3, and hydrotalcite (HT) as the support, respectively, and PdCl2 as the precursor. Catalytic performance of the catalysts for hydrogenation of phenol to cyclohexanone was evaluated in a fixed-bed reactor. These catalysts were characterized byX-raydiffraction, N2 adsorption, H2 temperature-programmed desorption, CO2 temperature-programmed desorption, andX-rayphotoelectron spectroscopy. The results showed that bigger average pore diameter, higher surface Pd content, and more surface base sites were favorable for the adsorption of hydrogen and phenol and consequently increased the conversion of phenol and the selectivity for cyclohexanone. Under the conditions of 130 ℃, H2∶phenol molar ratio = 4∶1, and LHSV=0.19 h-1, the conversion of phenol was 90% and the selectivity for cyclohexanone reached 97% over the 0.5%Pd/HT catalyst.

Key words: phenol, hydrogenation, cyclohexanone, palladium, support, hydrotalcite