Piotr Winiarek

Selective hydrogenation of α,β-unsaturated aldehydes over Pt catalysts deposited on monolayer supports

Abstract New Pt catalysts deposited on monolayer supports containing TiO 2 have been tested in the hydrogenation of α,β-unsaturated aldehydes. Enhancement of selectivity towards unsaturated alcohols has been observed in comparison to the commonly used Pt/SiO 2 or Pt/TiO 2 catalysts.

INVESTIGATION OF THE ACIDITY OF NI/AL2O3 AND NI/SIO2-AL2O3 CATALYSTS

Acidity of Ni-modified alumina and silica-alumina catalysts was determined using n-butylamine titration and pyridine adsorption methods. Strong influence of Ni2+ ions on the Brönsted acidity of silicaalumina was observed. Improved Brönsted acidity of such system was confirmed by the results of the test reaction.

Hydrogenation of unsaturated hydrocarbons over alkali-metal-modified zinc oxide

Superbasic catalytic systems have been obtained by evaporation of alkali metals onto a ZnO surface. The catalysts were characterized by IR and EPR spectroscopy. Similar to the case of alkali-metal-doped oxide insulators, surface colour centres Fs+, formed by the trapping of an alkali-atom electron in an oxide anionic vacancy, were identified as the source of the extremely strong one-electron donor properties. The studied catalysts exhibited a much higher activity in the hydrogenation of alkenes than the starting ZnO. A mechanism for propene hydrogenation over the superbasic alkali metal/ZnO system was proposed.

Transfer hydrogenation of phenanthrene in the presence of boron modified alumina or silica-alumina

Reactions of phenanthrene with hydrogen donors carried out in the presence of boron trifluoride etherate modified catalysts: silica, alumina or silica-alumina have been studied. Di-, tetra- and octahydrophenanthrenes as well as some bicyclic hydrocarbons were the reactions products. Their yields were strongly influenced by hydrogen donor polarity.

Hydrogenation of polyaromatic coal related hydrocarbons by hydrogen transfer

Abstract Hydrogen transfer between phenanthrene and tetralin or alcohols was performed at atmospheric pressure and at temperatures of 350, 400 and 450 °C using Pd, Ni, Fe catalysts deposited on different carriers. A strong influence of gaseous hydrogen was observed in the case of the tetralin-phenanthrene reaction. The importance of catalysis in such reactions is discussed with respect to coal conversion processes.

INFLUENCE OF GASEOUS HYDROGEN ON THE HYDROGEN TRANSFER REACTION BETWEEN PHENANTHRENE AND HYDROGEN DONORS

Transfer hydrogenation of phenanthrene was performed in the presence of superbases or strong acids and gaseous hydrogen. The influence of hydrogen on the yield of these reactions was discussed with respect to the mechanism of hydrogen transfer.

Isomerization of alkylaromatic hydrocarbons on nickel-boron-alumina catalysts

The activity of alumina and silica-alumina modified with nickel and/or boron trifluoride etherate in the transformations of o-xylene and α-methylnaphthalene in the presence of gaseous hydrogen has been measured. Dependence between the yields of isomerization reaction and the concentration of Brönsted acid centers on the surface of the catalysts investigated was observed.

Phenanthrene conversion in the presence of superbasic K/MgO catalyst

The activity of K/MgO superbasic catalyst in phenanthrene reactions with hydrogen or hydrogen donors is demonstrated, in which 9,10-dihydrophenanthrene and biphenyl derivatives are obtained. The influence of the hydrogen donor polarity on the yield of the reaction is observed.

Diphenylmethane transformations over boron trifluoride modified alumina and silica-alumina

Transformations of diphenylmethane were investigated in a flow system in the presence of alumina and silica-alumina modified with boron trifluoride at atmospheric pressure and elevated temperatures. Hydrogen transfer reaction was observed on addition of tetralin to the substrate stream.