One-pot gas-phase upgrading of low-carbon alcohols and acetone to C2-C8 olefins on Zn-Zr oxides

Abstract

ABE (acetone-butanol-ethanol) and IBE (isopropanol-butanol-ethanol) fermentation are well-established processes for producing ketones and alcohols from biomass. Using these low-carbon alcohols and acetone might improve the production of olefins. The gas-phase synthesis of light olefins from 1-butanol, ABE and IBE was investigated on Zn-Zr mixed oxides and reference ZnO and ZrO2. Zn-Zr catalysts with different Zn/Zr molar ratios (0.11–0.43) were prepared by incipient wetness impregnation of Zn on Zr(OH)4. The 1-butanol to olefin reaction pathways operating under different reaction conditions were elucidated. This tandem process comprises dehydrogenation, ketonization, aldol condensation, C–C bond cleavage, and deoxygenation reactions. ABE and IBE mixtures conversion was also evaluated, achieving total olefin yields of ∼65 %. Isobutene and ethylene (∼91 %) were the main components of the olefin fraction, while pentenes, isohexenes, heptenes, and octenes were the remaining components. These results highlight the potential of Zn-Zr oxides to develop a sustainable production of olefins.