T. Venäläinen

Behaviour of palladium and ruthenium catalysts on alumina and silica prepared by gas and liquid phase deposition in cinnamaldehyde hydrogenation

Study was made of the catalytic activity and selectivity of alumina and silica supported palladium and ruthenium catalysts in cinnamaldehyde hydrogenation. Palladium and ruthenium β-diketonate complexes were introduced onto alumina and silica supports by atomic layer epitaxy (ALE) and by conventional impregnation technique. Palladium catalysts were more active than ruthenium catalysts. ALE-prepared palladium catalysts showed the highest initial activity because of the small metal particle size. However, the reactivity of surface palladium atoms was highest in the large metal particles. ALE-prepared Ru on silica showed good selectivity in cinnamaldehyde hydrogenation; only hydrocinnamaldehyde and 3-phenyl-1-propanol were formed. All other catalysts gave a variety of products. ALE-prepared Ru on alumina had the highest selectivity to cinnamyl alcohol.

Ring opening of decalin over Pt-and Ir-modified SAPO-5 and VPI-5 zeolite catalysts

Ring opening of decalin over Pt- and Ir-modified SAPO-5 and VPI-5 catalysts was carried in a batch reactor at 573–623 K in the presence of hydrogen. The catalysts were synthesized and characterized by using XRD, nitrogen physisorption, pyridine desorption and CO chemisorption. Bronsted acidity was essential for both isomerization and ring-opening reactions. Presence of a noble metal was found to be beneficial for isomerization and ring opening as well.

Deposition of platinum into beta-zeolite

Abstract Platinum was deposited into beta zeolites with different techniques. Platinum was well-dispersed when the catalyst was prepared by ion exchange and Atomic Layer Epitaxy (ALE) deposition methods. In impregnation, the source material of platinum and post-treatments affected for the dispersion. Platinum dispersion was low when trimethyl(methylcyclopentadienyl)platinum impregnated beta zeolite was calcined prior to reduction. In calcination at 623 K in air most platinum was reduced. Platinum was totally reduced with hydrogen at 573 K. In pulsing of carbon monoxide at 300 K on platinum ALE catalyst, carbon dioxide formation was observed. Trimethyl(methylcyclopentadienyl)platinum impregnated beta zeolite produced selectively cinnamyl alcohol at low conversion whereas with other catalysts several different products were formed.