Vapor-phase hydrogenation of acetoin and diacetyl into 2,3-butanediol over supported metal catalysts

Vapor-phase catalytic production of 2,3-butanediol from acetoin and diacetyl was investigated over the supported metal catalysts such as Ni, Co, Cu, and Ag. A yield of 2,3-butanediol higher than 90% can be obtained from both acetoin and diacetyl over Ni/SiO 2 catalyst in an H 2 flow at 150 °C. Since the hydrogenation is an exothermic reaction, a low temperature is favorable to gain a full production of 2,3-butanediol. It was found that the equilibrium among 2,3-butanediol, acetoin, and diacetyl could be achieved at a contact time of the reactants with catalyst longer than 1.67 h. The pressure equilibrium constants in the hydrogenation were calculated by the outlet gas composition.