Study On Ni/Al_2O3 Catalyst For Hydrogenation Of Hydroxypivalaldehyde To Neopentyl Glycol

The thermodynamic parameters of neopentyl glycol and hydroxypivalaldehyde were estimated by using group contribution method. And the reaction thermodynamics of hydrogenation reaction was studied. The relationship between the reaction enthalpy change, Gibbs free energy, chemical equilibrium constant and reaction temperature was established. The results showed that the reaction is an exothermic reaction. While decreasing the reaction temperature, it can benefit the formation of the products. In this paper, the influence of preparation conditions on the catalyst was investigated, such as the precipitation agent, nickel content, precipitation method, precipitation pH and calcination temperature. According to the results, the optimal preparation process of Ni/Al2O3 catalyst was:choosing sodium carbonate as the precipitant, Ni:Al=1:2, choosing paralled flow as precipitation method, precipitation pH in about 7 and calcination temperature at 450 ℃. The effect of reduction condition, reaction temperature, reaction pressure, LHSV and the molar ratio between H2 and aldehyde to hydrogenation reaction were studied on Ni/Al2O3 catalyst. According to the results, the optimal HPA hydrogenation reaction conditions were reduction temperature at 450 ℃, reduction time on 4h, reaction temperature at 120℃, reaction pressure at 3.0MPa and liquid space velocity on 1.0h-1. In this condition, the HPA conversion was 100%, and the NPG selectivity was more than 98.5%.