Selective hydrogenation of methyl benzoate to benzaldehyde over a manganese‐based catalyst with weak acidity centres

Abstract Benzaldehyde is a prominent product resulting from the catalytic hydrogenation of methyl benzoate, which is commonly utilized as a key intermediate in the chemical industry. In this work, Mn/Al 2 O 3 catalysts with different loading contents were synthesized through the equal volume impregnation method. A systematic investigation of the selective hydrogenation of methyl benzoate was conducted to delve into the influence of loading capacity and support type. The optimized catalyst demonstrated outstanding catalytic performance, achieving a conversion rate of 97.2% and a benzaldehyde selectivity of 77.2% under the reaction conditions of 430°C, atmospheric pressure, a hydrogen and methyl benzoate molar ratio of 36:1, and a GHSV of 0.2 h −1 . The reaction mechanism of methyl benzoate to benzaldehyde was investigated by NH 3 ‐TPD and EPR experiments. The findings indicated that the abundant weak acidity of Al 2 O 3 in the Mn/Al 2 O 3 catalyst facilitated reactant adsorption, while an appropriate level of oxygen vacancy in the active centre MnO significantly enhanced benzaldehyde selectivity.