Hydrogenation of Phenol to Cyclohexanone in Aqueous Phase on WO3 Modified Ni/ZrO2 Catalyst

Ni/ZrO 2 (Ni/Zr) and Ni/WO 3 -ZrO 2 (Ni/ x WZr, x denotes WO 3 /ZrO 2 mass ratios) were prepared by the impregnation-direct reduction method and tested for the aqueous phase hydrogenation of phenol to cyclohexanone in an autoclave reactor. It has been found that the Ni-W alloy forms in Ni/ x WZr, and a charge transfer occurs from Ni to W. The presence of W species promotes the Ni dispersion and increases the amounts of acid sites and spilt-over hydrogen species. This leads to higher hydrogenation and direct deoxygenation activity of Ni/ x WZr than that of Ni/Zr. In addition, the W 6+ and W 4+ species, acted as Lewis acidic sites, may stabilize cyclohexanone and the hydrogenation of cyclohexanone to cyclohexanol is inhibited. Under suitable condition, the phenol conversion and the cyclohexanone selectivity reach 93.1 and 90.6% on Ni/0.8WZr, respectively.