III International Conference

PP-III-44METAL-CARBON NANOCOMPOSITE SYSTEMS AS HIGHLY SELECTIVECATALYSTS FOR CHLOROBENZENE TRANSFORMATIONSLokteva E.S., Kachevsky S.A., Yermakov A.Ye. 1 , Uimin M.A. 1 , Mysik A.A. 1M.V. Lomonosov Moscow State University, Moscow, Russia1 Physics of Metals Institute, Ural Branch of RAS, RussiaE-mail: les@kge.msu.ru, yermakov@imp.uran.ruGas phase reductive transformations of chlorobenzene in H 2 were investigated in thepresence of nanosized Pd and Ni particles encapsulated in carbon matrix. Palladium-basedcomposite was very selective in cyclohexane formation. On Ni-based composite only benzenewas formed in the temperature range of 50 – 300 °C.Nanocomposites on the base of Pd and Ni encapsulated (@) in carbon matrix were testedin chlorobenzene conversion to benzene and cyclohexane. These composites were preparedby novel method, which promotes their outstanding properties: from TEM, XPS and Ramanspectroscopy studies it is evident that systems have high metal dispersion, the mean diameterof metal particles is in range of 5 and 20 nm, and the metal concentration varies from 10 to50%. Also they possess high stability to oxidation because they have metal particles whichare covered with carbon.Cl Pd, H 2Pd, H 2- HClHydrodechlorination was carried out in a fixed-bed flow reactor under the excess ofhydrogen at 50 – 300 o C and atmospheric pressure using 0.05 g of catalyst. The products wereanalyzed by gas chromatography. The selectivity of catalysts based on different3d-metal changes dramatically. For example in presence of Pd@C total chlorobenzeneconversion was observed in temperature range of 150 – 200 °С, the only product wascyclohexane. When the temperature was decreased to 50 °С, chlorobenzene conversiondecreased from the value of 100 % to 90 %, the main product was benzene with 75 % yield.When Ni@C was used the process turns toward 100 % benzene formation with no signs offurther hydrogenation to cyclohexane in the temperature range of 50-300 °C.This work was supported by INTAS grant for Young Scientists(Ref. # 06-1000014-5597) and RFBR (grant # 04-03-32869).552