An in-situ hydrogenation process of methyl benzoate (MB) to benzaldehyde in gas phase was proposed.A Cu-MnO/γ-Al2O3 bi-functional catalyst was prepared with the impregnation method

and was used for the proposed process.The effects of catalyst composition

reaction temperature

feeding rate

and molar ratio of methyl benzoate/methanol/water in the feed on the conversion of methyl benzoate and the selectivity of benzaldehyde were investigated with a fixed-bed reactor under atmospheric pressure.Under the optimal conditions (molar ratio of MB/methanol/water

temperature and feeding rate were 0.5/40/40

420℃

0.1 ml8226;min-1)

the selectivity of benzaldehyde reached 88.5%

and the conversion of MB was 79.6%.In addition

the Cu-MnO/γ-Al2O3 catalyst was quite stable for such a reaction.Moreover

a reaction mechanism was proposed based on the product distribution of the in-situ hydrogenation of methyl benzoate to benzaldehyde.In this process

external supply of hydrogen was not needed

which is different from the traditional hydrogenation process in gas phase.