A remarkable promoting effect of water addition on selective hydrogenation of p-chloronitrobenzene in ethanol

Selective hydrogenation of p-chloronitrobenzene to p-chloraniline over ruthenium catalyst was found to be promoted remarkably (Selectivity: from 80.4% to 98.6%; TON: from 0.89 × 10−2 s−1 to 3.20 × 10−2 s−1) by simply adding some water into the solvent of ethanol. The optimized volume percent of water in ethanol was 30%. The promoting effect of water was also found over various supported metal catalysts, such as Fe/SiO2, Co/SiO2, Ni/SiO2, Cu/SiO2, and Ag/SiO2.