Highly selective hydrogenation of phenol to cyclohexanol over nano silica supported Ni catalysts in aqueous medium

Cyclohexanol is an excellent starting material for fuel production, but direct selective hydrogenation of phenol to cyclohexanol under mild conditions is a challenge. Herein we report a catalyst made of Ni nanoparticles supported on high-surface silica, which is highly active for selective formation of cyclohexanol under 1.0   Mpa pressure of hydrogen in aqueous medium without additives. Conversion of 100   mol% and selectivity up to 100% are achieved within 4   h and 1.0   MPa H 2 . Some factors such as the type of the source of silica, the loading of Ni, the reaction temperature and time, the H 2 pressure play important roles in controlling the selective hydrogenation. The generality of the 10%Ni/SiO 2 -1 catalyst for this reaction is demonstrated by selective hydrogenation of other hydroxylated aromatic compounds as well.