Conversion of 2,3-butanediol to butenes over bifunctional catalysts in a single reactor

Abstract In this study, Cu/ZSM-5 catalysts were used to catalyze the hydrodeoxygenation of 2,3-butanediol to butenes in a single reactor in the presence of hydrogen. The carbon selectivity of butenes increased with increasing SiO 2 /Al 2 O 3 ratio (lowering acidity of zeolite) and H 2 /2,3-butanediol ratio. Cu/ZSM-5 with a SiO 2 /Al 2 O 3 ratio of 280 showed the best activity toward the production of butenes; however, Cu/ZSM-5 with SiO 2 /Al 2 O 3 of 23 was favorable for the dehydrogenation reaction of 2,3-butanediol even in the excess of hydrogen. On zeolite ZSM-5(280), the carbon selectivity of butenes increased with increasing copper loading and 19.2 wt% of CuO showed the highest selectivity of butenes (maximum 71%). The optimal reaction temperature is around 250 °C. Experiments demonstrated that methyl ethyl ketone (MEK) and 2-methylpropanal are the intermediates in the conversion of 2,3-butanediol to butenes. The optimal performance toward the production of butene is the result of a balance between copper and acid catalytic functions.