The potential of ZrO2 catalysts for the dehydration of 2,3-butanediol into 3-buten-2-ol: Impact of synthesis method and operating conditions

Abstract

2,3-Butanediol (2,3-BDO) dehydration towards 1,3-butadiene was investigated over commercial and in-house synthesized ZrO2 catalysts in a Berty reactor at intrinsic kinetics conditions. The commercial and ZrO2 catalysts prepared via precipitation (ZrO2-PP) exhibited a higher selectivity towards the undesired methyl ethyl ketone which was attributed to a lack of sufficient acid-base concerted active sites. For ZrO2-PP, this was attributed to its tetragonal crystal structure with weaker adsorption sites. Hydrothermal synthesis allowed producing ZrO2 with a monoclinic crystal structure, with correspondingly more pronounced acidic and basic properties which could be further tuned via calcination. A maximal 3-buten-2-ol, i.e., the desired intermediate for further conversion into 1,3-butadiene, yield amounting to 38% (mol mol−1) could be obtained under a N2 flow at 300 °C, a space time of 1130 kg s mol−1 and 2,3-BDO partial pressure of 0.16 bar over the hydrothermally synthesized catalyst.