Influencia del Pb sobre las propiedades catalíticas de catalizadores Pt-Re/Al2O3 de reformado de naftas

V.A. MAZZIERI; J.M. GRAU; C.R. VERA; J.C. YORI; M. A. D´AMATO; C.L. PIECK

Buenos Aires, Argentina

Congreso; XVI Congreso Argentino de Catálisis; 2009

Sociedad Argentina de Catálisis

The influence of the addition of Pb on the performance of Pt-Re/Al2O3 naphtha reforming catalysts was studied.  The catalysts were prepared by coimpregnation. They were characterized by temperature programmed reduction, temperature programmed desorption of pyridine and different reactions such as dehydrogenation of cyclohexane, hydrogenolysis of cyclopentane and reforming of n-heptane.  It was found that Pb is in close interaction with the active phase (Pt-Re).  As a consequence the metal activity is decreased upon Pb addition.  Hydrogenolysis is more affected than dehydrogenation.  Part of Pb is deposited on the support decreasing its total acidity and the concentration of strong acid sites.  The n-heptane reaction results show that Pb addition increases the stability and selectivity of the Pt-Re catalysts.     Small Pb additions increase the stability and significantly improve the selectivity towards C7 isomers and aromatics while decreasing the formation of low value gases.