CATALYTIC BEHAVIOR OF SILICA-SUPPORTED POLYSILAZANE PLATINUM COMPLEX IN THE HYDROGENATION OF XYLENES

The effects of various reaction parameters on the catalytic activity a nd stereoselectivity in the hydrogenation of the isomeric xylenes over a silica-supported polysilazane-platinum complex (Si-N-Pt) have been studied. The ratio of cis and h-ans dimethylcyclohexane is a function of the structure of the substrate, temperature and catalyst concentrat ion etc. cis-Dimethylcyclohexane is the more favored product for each of the three xylene isomers. The cis/trans ratio drops in the followin g order: o-xylene > m-xylene > p-xylene. The proportion of the cis iso mer decreases with elevating temperature or decreasing substrate/catal yst mole ratio.