O-XYLENE HYDROGENATION ON SUPPORTED RUTHENIUM CATALYSTS

The influence of the support on the surface properties and catalytic a ctivity of finely divided ruthenium catalysts is reported. The catalys ts were prepared using an organometallic precursor, Ru(acac)(2) , and three different supports, Al2O3, TiO2 and SiO2. In order to study the influence of the particle size on the catalytic performance, the effec t of the calcination temperature was also evaluated. XPS suggests that the state of ruthenium is essentially Ru-0, and chemisorption measure ments indicate a decrease in metal dispersion from catalysts supported on Al2O3 > TiO2 > SiO2 The turnover number in the o-xylene hydrogenat ion showed significant differences depending on the support and on the particle size. Additionally, an increase in the selectivity to cis-di methylcyclohexane with particle size was observed.