Liquid phase hydrogenation of crotonaldehyde over Au/CeO2 catalysts

Three Au/CeO2 catalysts, with different specific surface area (80, 150 and 240 m2/g) were tested for the hydrogenation of crotonaldehyde in liquid phase. Reactions were carried out with molecular hydrogen as the reductant, in a batch reactor using isopropanol as the solvent, at 80 deg C and 1 MPa. The high surface area catalyst (Au/CeO2, 240 m2/g) showed a selectivity towards crotyl alcohol of 29%. This value was much lower than the one previously obtained for the same sample under gas phase conditions (73%) [B. Campo, C. Petit, M. Volpe, J. Catal. 242 (2006) 162]. Under liquid phase the promotional effect of high surface area ceria is lost. The low and middle surface area samples (80 and 150 m2/g respectively) showed meager selectivity to carbonyl hydrogenation due to both the low promotional effect of the support and the relatively large size of gold particles. For the three catalysts the formation of propanol was observed, which decreases catalysts selectivity to crotyl alcohol.