Preparation of polymetallic reforming catalysts and their use in reforming naphtha

A catalyst useful for reforming a naphtha feed at reforming conditions which comprises an iridium component dispersed throughout and bound within an alumina support matrix, a platinum component dispersed upon said iridium-containing alumina support, and halogen. In all of its aspects, the iridium component will remain in its dispersed state, without significant agglomeration, when subjected to temperatures in the presence of oxygen for extended periods sufficient to agglomerate presently known halogenated platinum-iridium catalyst. The catalyst may be prepared in an initial step by dispersing the iridium within the alumina matrix or a precursor thereof from which the matrix is formed, and then calcining the iridium-containing alumina composite at high temperature to bind the iridium within the resulting alumina support matrix. The platinum, or platinum and additional metal promoters, especially rhenium, is then impregnated upon the iridium-alumina support. This catalyst can be used in reforming at reforming conditions to provide high activity, high activity maintenance, high sulfur tolerance, low coke make anbd high C5 liquid volum yield.