DESEMPENHO DE CATALISADORES DO TIPO Ge-Pt-Re/Al2O3, PREPARADOS POR DIFERENTES MÉTODOS, NA REFORMA DE n-OCTANO

K.C.S. CONCEIÇÃO; L.S. CARVALHO; J.L.G. FIERRO; V.A.MAZZIERI; C.L. PIECK; J.M. GRAU; M.C. RANGEL

Punto Fijo

Congreso; XVIII Congreso Venezolano de Catálisis; 2011

Sociedad Venezolana de Catálisis

Catalysts containing germanium, platinum and rhenium supported on alumina chlorinated were studied by varying the preparation method. The samples were prepared by successive impregnations, using 0.3% of each metal and submitted to oxidation and/or reduction treatments during the stages of impregnation. The solids were characterized by thermoprogrammed reduction, temperature programmed desorption  of pyridine and X-ray photoelectron spectroscopy. The catalysts were evaluated in cyclohexane dehydrogenation, cyclopentane hydrogenolysis and n-octane desidrocyclization. The solid performance was affected by the heat treatments to which they were submitted. The reduction steps led to an increase in dehydrogenation activity for Pt-Ge samples and the inverse occurred for Pt-Re ones. The hydrogenolytic activity was reduced for the bimetallic catalysts containing germanium but decreased for the bimetallic ones containing rhenium. For the trimetallic samples, the preparation method with three oxidation steps generated a solid with the highest dispersion and therefore the most active in cyclohexane dehydrogenation; besides, it was the most selective to aromatics. On the other hand, the use of three reduction steps led to the most active catalyst  in cyclopentane hydrogenolysis and most selective to isomers.