Synthesis of Cyclohexylbenzene by Hydroalkylation of Benzene over Pd/Hβ Binary Catalyst

The Pd/Hβ binary catalyst was prepared by the impregnation method and was used for the hydroalkylation of benzene to cyclohexylbenzene. The effects of reaction temperature, reaction time, hydrogen pressure, Hβ acidity, and metal loading were investigated. The results indicated that the conversion of benzene and the selectivity for cyclohexylbenzene approached 24.3% and 88.0%, respectively, under the conditions of 2.5 MPa H2, 200°C, and 3 h. The preferable balance between metal active sites and acidic sites in the catalyst was the key to the hydroalkylation of benzene. The mechanism of the reaction was discussed.