Aqueous biphasic hydrogenation of benzene catalyzed by ruthenium complex of trisulfonated tris(biphenyl)phosphine

Ruthenium-catalyzed aqueous biphasic hydrogenation of benzene was investigated using the water-soluble ligand trisulfonated tris(biphenyl)phosphine (BiphTS). The ruthenium/BiphTS system exhibited an efficient catalytic activity and effectively hydrogenated benzene to cyclohexane with 100% selectivity under mild conditions. The effect of reaction temperature, partial pressure of hydrogen, ligand/Ru molar ratio, benzene/Ru molar ratio, non-ionic surfactants, thiophene concentration and reusability of catalyst were investigated systematically for the hydrogenation of benzene. A considerably high TOF (up to 8000 h(-1)) was obtained in the presence of mass transfer promoters (such as non ionic surfactants). The Ru/BiphTS was easily recovered from the product by a simple phase separation and recycled.