Direct ethyl acetate synthesis from ethanol over amorphous-, monoclinic-, tetragonal ZrO2 supported copper catalysts prepared from the same zirconium source

Abstract

Direct ethyl acetate synthesis from ethanol was examined by supported Cu catalysts on various kinds of acid-base metal oxides, available ZrO2-based oxides, and homemade amorphous-, monoclinic- and tetragonal zirconia prepared from the same Zr source. XRD, XAFS, TG-DTA characterization and surface area measurement were performed. Effects of crystalline phase of ZrO2 support on selective ethyl acetate production was discussed based on the yields and products ratio (ethyl acetate to sum of C4-alcohols and aldehydes). Based on catalytic performance by 29 kinds of homemade catalysts, amorphous-type ZrO2 was found to be essentially the most suitable ZrO2 phase for the selective ethyl acetate formation in cases without any surface modifications. The acid site on the surface of monoclinic-type ZrO2 catalysts possibly promoted unfavorable acetaldehyde condensation reaction, but addition of Na+ for poisoning could increase selectivity of ethyl acetate formation. Coordination environment of Cu species for fresh and spent catalysts were discussed.