INCAPE   05401
INSTITUTO DE INVESTIGACIONES EN CATALISIS Y PETROQUIMICA "ING. JOSE MIGUEL PARERA"
Unidad Ejecutora - UE
artículos
Título:
PtReGe/Al2O3 catalysts for n-octane reforming: Influence of the order of addition of the metal precursors
Autor/es:
L.S. CARVALHO; K.C.S. CONCEIÇÃO; V.A. MAZZIERI; P. REYES; C.L. PIECK; M.C. RANGEL
Revista:
APPLIED CATALYSIS A-GENERAL
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2012 vol. 419 p. 156 - 163
ISSN:
0926-860X
Resumen:
Trimetallic PtReGe supported catalysts for naphtha reforming were prepared by successive impregnation
of suitable precursors on gamma alumina. The order of addition of these precursors was varied
and its influence on the catalytic properties was assessed by means of the model reaction of n-octane
reforming. It was found that the order of addition of the metal precursors greatly affects the performance
and properties of these systems, which in turn is closely related to the first impregnated metal. When
platinum is impregnated before rhenium and germanium the metals are reduced separately resulting
in catalysts with high dehydrogenation activity and low hydrogenolysis activity. On the other hand, the
impregnation of germanium before the other metals leads to the production of catalysts with low activities
for dehydrogenation and high activity for hydrogenolysis, as a consequence of the strong interactions
among the metals. By adding rhenium before the other metals, catalysts with intermediate behavior are
produced. For all catalysts, platinum interacts more strongly with rhenium than with germanium. The
order of addition does not modify the acidic properties of the support but germanium and rhenium seem
to change the acidity of the support in the vicinity of the metals, causing differences in the selectivity
to aromatic compounds and paraffinic isomers. These features can be used to tailor catalysts with high
selectivity for the production of aromatics or isoparaffins, depending on the purpose of the reforming
process. The RePtGe catalyst has the highest selectivity to branched isoparaffins and then can be used
to produce isoparaffins-rich gasoline while a reformate rich in aromatics can be obtained by using the
GeRePt catalyst.