Evaluation of the effect of methanol as an in-situ hydrogen source on the reduction of methyl acetate to ethanol

Abstract

A process was proposed to hydrogenate methyl acetate to ethanol using methanol as an in-situ hydrogen donor over a Cu/SiO2 catalyst. The catalyst was characterized by XRD, H2-TPR, XPS, and FT-IR, and the structure information of the catalyst was obtained. The effects of CH3OH, H2 and mixed hydrogen source on the hydrogenation of methyl acetate on the same catalyst surface were compared, and it was concluded that methanol was an efficient hydrogen source. Furthermore, the influences of process conditions such as temperature and alcohol/ester ratio on methanol conversion, methyl ester conversion, and ethanol selectivity were investigated. The coupling mechanism was analyzed, that methanol decomposition to obtain in-situ hydrogen for methyl ester hydrogenation on a copper-based catalyst. The results showed that methanol as an in-situ hydrogen source could promote not only the efficient hydrogenation of methyl acetate but also inhibit the transesterification side reaction. At a lower alcohol/ester ratio, 90.9% ethanol selectivity and 82.8% methyl acetate conversion could be obtained using only the unmodified catalyst.