Abstract

Hydrocarbons are converted by contacting them at hydrocarbon conversion conditions with a sulfided acidic multimetallic catalytic composite comprising a combination of catalytically effective amounts of a platinum or palladium component, a rhodium component, a component with a porous carrier material. The platinum or palladium component, rhodium component, lead component, halogen component, and sulfur component are present in the multimetallic catalyst in amounts respectively, calculated on an elemental basis, corresponding to about 0.01 to about 2 wt. % platinum or palladium metal, about 0.01 to about 2 wt. % rhodium, an atomic ratio of lead to platinum or palladium of about 0.05:1 to about 0.9:1, about 0.1 to about 3.5 wt. % halogen, and about 0.01 to about 1 wt. % sulfur. Moreover, the metallic components are uniformly dispersed throughout the porous carrier material in carefully controlled oxidation states such that substantially all of the platinum or palladium component and the rhodium component are present therein in a sulfided state or in a mixture of the sulfided state and the elemental metallic state and such that substantially all of the lead component is present therein in an oxidation state above the elemental metal. The sulfiding of the catalytic composite is performed prior to any contact of the composite with hydrocarbon and after substantially all of the platinum or palladium and rhodium components are reduced to the elemental metallic state by treatment with a sulfiding gas at conditions selected to incorporate about 0.01 to about 1 wt. % sulfur. The resulting sulfided acidic catalyst has the capability of diminishing undesired demethylation and other hydrogenolysis reactions during initial operation of the process and markedly increasing the over-all stability of the process.