A new catalyst system was used in the liquid phase hydrogenation of benzene to cyclohexene containing only an aqueous solution of Ru/La₂O₃ and a very small quantity of sodium dicyanamide (NaDCA). This additive considerably improves the catalyst performance compared to DCA based ionic liquids. The effects of the amount of NaDCA and metal loading of the catalyst were investigated and a high initial selectivity to cyclohexene of 70% was reached.