Vapor phase selective hydrogenation of furfural to furfuryl alcohol over Cu-MgO coprecipitated catalysts

Cu-MgO catalysts have been employed for the catalytic vapor phase hydrogenation of furfural (FAL) to furfuryl alcohol (FOL) at atmospheric pressure, H-2/furfural (molar ratio) = 2.5 and the gas hourly space velocity (GHSV) has been maintained at 0.05 mol h(-1) g cat(-1). Cu-MgO catalysts with variable Cu loadings (5.2-79.8 wt.%) are prepared by coprecipitation method and are characterized by BET surface area, AAS (atomic adsorption spectroscopy), XRD, XPS and DTA/TGA. Hydrogenation activities of the catalysts, reduced at 523 K in H, flow for 4 h prior to the reaction are studied in the temperature range of 453-523 K. Cu-MgO catalyst with 16 wt.% of Cu showed hydrogenation activity with 98% conversion of furfural producing furfuryl alcohol with a higher selectivity of 98%. XPS analysis showed the presence of Cu-0/Cu+ sites on the catalyst surface that may be responsible for the higher activity compared to other Cu-MgO catalysts studied. The turnover frequency of furfural conversion in the catalysts containing lower composition of Cu is very high. However, due to the lack of required number of Cu-0 particles and the absence of Cu' species in these catalysts, the overall conversion of furfural is low. (c) 2006 Elsevier B.V. All rights reserved.