Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

PP-V-3half-hydrogenated inter-mediates. Harmful influence of trans-isomers on human’s health iswell known. The tendency of a metal to promote one of the routes is closely related to particlesize of the active metal and metal distribution throughout the support grain. In this workhydrogenation of rapeseed oil was carried out at 373 K, P H2 =6 atm in an autoclave underefficient stirring. Products were analyzed by GC and FTIR-spectroscopy. The obtained results(Table 1) indicate that in order to avoid trans-isomers formation it is necessary to decrease Pdparticle size and to provide egg-shell distribution of Pd throughout the support grain.1% (wt) Pd/C and 4% (wt) Pd/C powdered catalysts were tested in selective oxidation oflactose into lactobionic acid (LBA). Since oxidation of sugars is very sensitive to thecomposition of the adsorbed layer, «in-situ» measurements of electrochemical catalystpotential during a reaction reflect the oxygen coverage on the catalyst surface [2]. In this workkinetic measurements for a variety of Pd/C catalysts with different metal loading and differentpreparation techniques in comparison with a commercial catalyst (Degussa) werepresented (Figure 1).concentration LBA, mol0,080,070,060,050,040,030,020,011% Pd/C Methods I-II4% Pd/C Method II4% Pd/C Method I4% Pd/C Method IV5% Pd/C Degussa0,000 50 100 150 200time, mina) b)E, mV2001000-100-200-300-400-500-6001% Pd/C Methods I-II4% Pd/C Method II4% Pd/C Method I4% Pd/C Method IV5% Pd/C Degussa-7000,0 0,2 0,4 0,6 0,8 1,0Lactose ConversionFigure 1. Lactose oxidation over palladium catalysts at 343 K, pH=8.a) Concentration vs time, b) Catalyst potential vs conversion.Significant differences in catalytic behavior and catalyst potential responses duringlactose oxidation can be noticed from Figure 1, reflecting the nature of catalytic systems. Thestrong relationship between the metal dispersion, metal loading and the catalyst performancewas found. More details on the relationship between the metal dispersion, metal loading,support properties and the catalyst performance will be provided in the presentation.References1. P.A. Simonov, S.Yu. Troickii and V.A. Likholobov, Kinet.Catal. 41 (2000) 281.2. A.V. Tokarev, E.V. Murzina, J. Kuusisto, J.-P. Mikkola, K. Eränen and D.Yu. Murzin, J. Molec. Catal. A.Chem., 255 (2006) 199.463