Preparation and characterization of trimetallic Pt-Re-Ge/Al2O3 and Pt-Ir-Ge/Al2O3 reforming catalysts

M. BOUTZELOIT; V.M. BENITEZ; C. ESPECEL; F. EPRON; C.R. VERA; C.L. PIECK; P. MARÉCOT

Philadelphia, United States of America

Jornada; Catalysis Society, XIX North American Meeting; 2005

North American Catalysis Society

Catalytic reforming is an important process for the production of high-octane gasoline, aromatics and hydrogen from naphtha. Since the appearance of rhenium promoted platinum catalyst in 1968, a number of metallic promoters (e. g. Re, Ir, Sn) have been used as additives to increase the stability and selectivity of the traditional reforming catalyst, Pt supported on acidic alumina. The beneficial effect of Re or Ir on the properties of industrial catalysts is achieved only after sulfuration, sulfur having the ability of passivating the hydrogenolytic activity of the metallic function. However, these catalysts, even presulfided, exhibited an undesirable hydrogenolysis activity, particularly at high pressure. In previous studies we investigated the preparation of trimetallic Pt-Ir-Sn/Al2O3 [1] and Pt-Re-Sn/Al2O3 [2, 3] catalysts in order to replace the sulfuration of the bimetallic phase by the addition of an inactive modifier such as tin. In the present study, we investigate the controlled preparation of trimetallic 0.3Pt-0.3Re-xGe/Al2O3 and 0.55Pt-0.05Ir-xGe/Al2O3 reforming catalysts by catalytic reduction. Catalysts are characterized by elemental analysis, and the interaction between germanium and the bimetallic Pt-Re or Pt-Ir phases are evaluated by temperature programmed reduction (TPR), and three catalytic tests, the cyclohexane dehydrogenation, the cyclopentane hydrogenolysis and the n-heptane conversion.