Based on the fact that reactant phenol is immiscible with water at room temperature

while it is soluble at the reaction temperature

and the products cyclohexanone and cyclohexanol are slightly soluble in water

water as the green solvent instead of volatile solvents of organic compounds is proposed and used for phenol catalytic hydrogenationFor this process

the reaction rate is not limited by the solubility of reactant into water

and the products can be easily separated from the solvent water by phase separation technique after reactionMeanwhile

the solvent water after reaction could be reused

which indicates that it is an environmental benign processFurthermore

it might be a potential approach to increasing the reaction rate of organic hydrogenation and improving the selectivity to desired products due to the different adsorptiondesorption properties of reactants and products on the surface of catalyst in various solventsFor example Raney Ni is of more powerful adsorption to H2 in water than in organic solvent.