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

OP-V-4Catalyst deactivation was more severe with very small Pd particles, whereas completeconversion of stearic acid was achieved with the catalyst exhibiting optimum dispersion.The main products were hepta- and pentadecane, which were formed in a parallel fashionup to 45% conversion, thereafter heptadecane reacted further to pentadecane and thus thereaction proceeded both parallelly and consecutively to these two products. Selectivity ofheptadecane as a function of stearic acid conversion is shown in Fig. 1b. No other liquidphase products were observed. Analysis of the gas phase products revealed presence ofmethane, carbon dioxide, carbon monoxide, propene and propane indicating that bothdecarbonylation and decarboxylation took place.a) b)1.00.80.600.55Mol %0.60.40.2Selectivity to C170.500.450.400.350.00 100 200 300 400Time, min0.300.0 0.2 0.4 0.6 0.8 1.0C18 conversionFig. 1. a) Deoxygenation of stearic acid and b) selectivity to heptadecane as a function of conversion over differentPd/C catalysts at 300°C under 17 bar. Symbols: Pd dispersion 18% (•), 47% (♦), 65% (•) and 72% (▲).4. ConclusionsSeveral supported palladium catalysts with varying metal dispersions were tested instearic acid deoxygenation. Catalyst deactivation was found to be crucial using lower amountsof catalyst. There was an optimum metal dispersion exhibiting the highest reaction rate. Themain products were hepta- and pentadecane being formed parallelly. At high conversionlevels of stearic acid heptadecane reacted consecutively to pentadecane. The reactionmechanism will be discussed in the final presentation.AcknowledgmentsThe part of research work was supported by RFBR Grant № 07-03-12159.References1. Snåre, M., Kubickova, I., Mäki-Arvela, P., Eränen, K., Murzin, D.Yu., Ind.Engn Chem. Res. 45 (2006),5708.2. Mäki-Arvela, P., Kubickova, I., Eränen, K., Snåre, M., Murzin, D. Yu., Energy and Fuels, 21 (2007), 30.3. Snåre, M., Kubickova, I., Mäki-Arvela, P., Eränen, K., Murzin, D. Yu., Catal Org. React. 115 (2006), 415.4. P.A. Simonov, S.Yu. Troitskii, V.A. Likholobov, Kinet. Catal. (Russ. Ed.) 41 (2000), 281.174