CATALYTIC TESTING OF TIO2 PLATINUM/SILICALITE-1 COMPOSITES/

The synthesis, characterisation and testing of a composite catalyst, c onsisting of TiO2-supported platinum catalyst particles covered with a 0.8-1.3 mu m thick silicalite-1 layer, are described. The composite s hows mass transport selectivity which is demonstrated by the high rati os of the initial conversion rates in the competitive hydrogenation of a Linear and a dibranched alkene, reaching average values of 35 at 10 0 degrees C. At the temperatures applied, adsorption of the alkene is dominant and hydrogen supply to the catalytic sites is relatively smal l. As a result the double-bond migration is more pronounced than with an uncovered platinum catalyst. At the catalytic sites of the composit es steric constraints are observed, which lead to regioselectivity in the hydrogenation of long-chain alkenes. A linear alkene with a termin al double bond is converted preferentially over an isomer with an inte rnal double bond.