Hydrogen-Free Gas-Phase Deoxydehydration of 2,3-Butanediol to Butene on Silica-Supported Vanadium Catalysts

The gas-phase deoxydehydration of 2,3-butanediol to butene was investigated in a plug flow reactor over SiO2-supported vanadium oxide, γ-alumina, P/ZSM-5, and MgO catalysts with acid/base sites of varying strengths. 5 wt % vanadium on SiO2 (i.e., 5V/SiO2) showed the best performance with 100 % conversion and up to 45.2 % butene selectivity. The combination of weak acid sites and polymeric VOx surface species provided the 5V/SiO2 catalyst with bifunctional capabilities to achieve both dehydration and transfer hydrogenation, which allowed it to catalyze the deoxydehydration of 2,3-butanediol to butene even in the absence of H2. As 2,3-butanediol is a common yet underutilized biomass product, this reaction may provide a viable route for a biomass-to-chemicals application for 2,3-butanediol.