Kinetics of nitrobenzene hydrogenation on spongy nickel and catalyst with supported palladium in 2-propanol aqueous solutions with acid or base additives

Resumo

The effect acetic acid and sodium hydroxide additives in a 2-propanol aqueous solution of azeotrope composition have on the rate of nitrobenzene (NB) hydrogenation over spongy nickel and supported palladium catalysts is studied. Analysis of the experimental data indicates that adding acid slows the rate more than adding a base during NB hydrogenation on spongy nickel. The observed rate for spongy nickel falls in a series of solvents: 2-propanol–water (0.68 mole fraction) > 2-propanol–water (0.68 mole fraction) + NaOH (0.01M) > 2-propanol–water (0.68 mole fraction) + CH₃COOH (0.01 M). When a palladium catalyst is used, the addition of acid has less of an effect on slowing the rate of the reaction than that of the base: 2-propanol–water (0.68 mole fraction) > 2-propanol–water (0.68 mole fraction) + CH₃COOH (0.01 M) > 2-propanol–water (0.68 mole fraction) + NaOH (0.01 M).