CHARACTERIZATION AND NITRILE GROUP HYDROGENATION STUDY OF SUPPORTED AND UNSUPPORTED RU-CO CATALYST

Characterization studies of a mixed Ru-Co catalyst unsupported and sup ported on SiO2 were performed. We also examined the effect of the cata lyst on hydrogenation of nitrile compounds. TPR shows that Co(II) in a n unsupported Ru(OH)x/Co(OH)y precursor is easily reduced at around 47 3-573 K, whereas the hydrogen reduction of Co(II) in the Ru(OH)x-Co(OH )y/SiO2 did not occur even at 873 K. X-ray adsorption fine structure m easurements indicated that both metals of the unsupported Ru/Co cataly st are reduced to their respective metallic state, and it is thought t hat Co-0-Ru-0 alloy is formed. However, Ru and Co exist as Ru-0 metal and Co oxide, respectively, in the case of a SiO2 supported catalyst. An unsupported Ru-Co catalyst shows higher activity for the hydrogenat ion of nitrile group and reductive amination of C=0 group of isophoron enitrile and the hydrogenation of nitrile groups of adiponitrile, succ inonitrile, and dicyanobenzene than the SiO2 supported catalyst does. It is suggested that this high performance of the unsupported catalyst is based on the formation of Ru-0-Co-0 alloy. (C) 1996 Academic Press , Inc.