A Study On Gaseous Phase Hydrogenation Of Ethyl Acetate To Ethanol With Cu-Mg Catalysts

As a potential alternative to oil,the development of ethanol fuel becomes increasingly popular in recent years.The acetic acid esterificaiton hydrogenation method is a new process in production of ethanol.However,the key is to develop the process of ethyl acetate to ethanol while the esterification of acetic acid to ethyl acetate is a mature technology.In this paper,a series of non-noble metal-based catalysts were prepared by different methods and systematically investigated.Of all tested samples,26 wt%Cu/SiO₂ catalyst prepared by co-precipitation with sodium silicate as the precipitate exhibited the best hydrogenation performance in the fixed-bed micro-reactor.Based on these results,the effects of promoters of catalysts,Cu/Mg molar ratios and calcination temperatures of catalysts on hydrogenation of ethyl acetate were investigated,from which the 26 wt%Cu₃/Mg-SiO₂ catalyst with 500?calcination temperature showed the best catalytic performance.The effects of reduction temperatures,reduction pressures,reaction temperatures,reaction pressures,H₂/EA molar ratios and ethyl acetate liquid hourly space velocities on catalytic performances of the 26%Cu₃/Mg-SiO₂ catalyst were further studied,showing that the hydrogenation performed well with 96.25%conversion and 94.27%ethanol selectivity respectively when reduction temperature,reduction pressure,reaction temperature,reaction pressure,H₂/EA molar ratio and ethyl acetate liquid hourly space velocity were 350?,1MPa,280?,2Mpa,30 and 1h^-1 respectively.The 26 wt%Cu₃/Mg-SiO₂ catalyst showed the excellent stability for hydrogenation of ethyl acetate through a 52-hour continuous reaction test.Catalysts under different conditions were characterized by XRD,TEM,H₂-TPR and XPS.The reaction mechanism of ethyl acetate hydrogenation over the Cu/Mg-SiO₂ catalyst,summarized below,was proposed based on the characterization and reaction results,that during hydrogenation reactions,magnesium oxides adsorb the raw materials and transfer them to the active site,while Cu⁰/Cu⁺ as active sites activate hydrogen and supply H atoms.