Hydrogen solubility was measured for four equimolar binary solvent mixtures, benzene + toluene, cyclohexane + methylcyclohexane, benzene + methylcyclohexane and cyclohexane + toluene, and an equimolar quaternary, benzene + cyclohexane + methylcyclohexane + toluene, in the pressure range from 1.077 to 4.580 MPa at 303.15 K. The hydrogen solubility increased linearly with the pressure for all systems. The binary interaction parameters, in a mixing rule of Peng-Robinson (PR) equation of state, were determined for benzene + toluene and cyclohexane + methylcyclohexane from the vapor-liquid equilibrium data of literature, and that for benzene + methylcyclohexane and cyclohexane + toluene from the hydrogen solubility data in the binary solvent mixture. Using the optimized binary interaction parameters, PR equation well predicted the experimental data for the quaternary. (c) 2007 Elsevier B.V. All rights reserved.