Indium, as an efficient co‐catalyst of Cu/Al2O3 in the selective hydrogenation of biomass derived fatty acids to alcohols

Abstract

Octanoic acid (OA) as model reactant of medium chain length, and its reduced products, octanal and octanol were hydroconverted over different components of a CuIn/Al2O3 composite catalyst. A fixed‐bed flow through reactor was used at 21 bar total pressure in the temperature range of 240–360 °C. Fatty acid hydroconversion activity of alumina supported Cu catalyst and mainly the yield of selectively produced octanol can be greatly increased by In2O3 doping, suppressing the dehydration side reactions. Appearance of metallic indium on alumina supported reduced copper catalyst can arrest the consecutive catalytic reaction at the alcohol formation step prior to further dehydration to ether or alkenes. An industrial, conventionally used Adkins catalyst (72 wt.% CuCr2O4 and 28 wt.% CuO) and the novel bimetallic composite (CuIn/Al2O3) were compared: both produce octanol with high selectivity, but the new chromium‐free fatty acid hydrogenation catalyst is more active, nearly as active as earlier investigated NiIn/Al2O3.