Active species of copper chromite catalyst in C-O hydrogenolysis of 5-methylfurfuryl alcohol

The active sites of copper chromite catalyst, CuCr2O4 center dot CuO, were investigated for the condensed-phase hydrogenolysis of 5-methylfurfuryl alcohol to 2,5-dimethylfuran at 220 degrees C. The bulk and surface features of the catalyst were characterized by XRD, H-2-TPR, N-2 adsorption, CO chemisorption, N2O titration, NH3-TPD, XPS, and AES. Maxima of both of the potential active species, Cu-0 and Cu+, occurred after reduction in H-2 at 300 degrees C compared to 240 and 360 degrees C. These Cu-0 and Cu+ maxima also coincided with the highest specific rate of reaction based on the surface area of the reduced catalyst. The trends of Cu-0 and Cu+ observed by N2O titration and CO chemisorption were also observed qualitatively by AES. Correlations between activity and the possible active species suggested that Cu-0 was primarily responsible for the activity of the catalysts. (C) 2011 Elsevier Inc. All rights reserved.