Efficient Catalytic Transfer Hydrogenation of Acetophenone to 1-Phenylethanol over Cu–Zn–Al Catalysts

Abstract

Cu–Zn–Al catalyst was prepared by the co-precipitation method, and the catalytic performance for transfer hydrogenation of acetophenone (AP) to 1-phenylethanol (1-PhE) was evaluated using isopropanol (IPA) as a hydrogen source. The addition of Zn changed the morphology of the catalyst and reduced aggregation of catalyst particles, resulting in highly dispersed Cu active sites. As the Zn content increased, the valence state of Cu species changed. When the Cu/Zn molar ratio was 2/3, the Cu+/Cu0 ratio in the catalyst was 0.81, resulting in good selectivity for 1-PhE. The reaction conditions were optimized over the Cu–Zn–Al catalyst with a Cu/Zn molar ratio of 2/3. When the reaction was performed at 180 °C for 2 h with an IPA/AP molar ratio of 15, the AP conversion was 89.4% and the 1-PhE selectivity was 93.2%. The Cu–Zn–Al catalyst showed good stability, and AP conversion and the 1-PhE selectivity were essentially unchanged after five cycles.