Solvent effects in catalytic hydrogenation

Solvents are known to have a significant effect on the rates of catalytic hydrogenations. The effect of the solvent is attributed to various factors, which include solubility of hydrogen, thermodynamic interaction of solvent with reactants and products, competitive adsorption of solvent, etc. In this paper the relative importance of the above factors in the hydrogenation of o-nitrotoluene using palladium-on-carbon catalyst is investigated. It is shown that the thermodynamic interaction between the solvent and the reactant is likely to be the dominant factor. The activity coefficient is shown to be a convenient parameter for a priori estimation of this effect.