Kinetic Studies on Hydrogenation of 2-Ethylhexanal and Its Side Reactions

Abstract

In the liquid-phase hydrogenation of 2-ethylhexanal over nickel-kieselguhr under pressure, 2-ethylhexanal(di-2-ethylhexyl) acetal is produced in the equilibrium state between 2-ethylhexanal and 2-ethylhexanol, as shown in the following scheme; [2-ethylhexanal] + 2[2-ethylhexanol] [2-ethylhexanal (di-2-ethylhexyl) acetal] + [H₂O] Equilibrium constant of the acetal formation was measured at various temperatures and the enthalpy of formation was found to be -10.6 kcal/mol. It was also found that the hydrogenolysis reaction of 2-ethylhexanal(di-2-ethylhexyl)acetal over the nickel-kieselguhr catalyst is of the first order reaction and activation energy of the reaction is about 10.2 kcal/mol. Effect of organic acids and water as additives on the reaction rate of 2-ethylhexanal hydrogenation and on its side reaction was studied.