Process for upgrading desulfurized naphthas

Claim 1

A PROCESS FOR PRODUCING A GASOLINE MOTOR FUEL HAVING ENHANCED ROAD PERFORMANCE CHARACTERISTICS WHICH COMPRISES FRACTIONATING A DESULFURIZED, VIRGIN PETROLEUM NAPHTHA BOILING BETWEEN ABOUT 90* AND 400*F. INTO A LOW-BOILING FRACTION CONSISTING ESSENTIALLY OF N-C7 AND LOWER-BOILING HYDROCARBONS PRESENT IN SAID NAPHTHA, AND A CONSECUTIVE HIGH-BOILING FRACTION CONTAINING SUBSTANTIALLY ALL THE HYDROCARBONS PRESENT IN SAID NAPHTHA HAVING A BOILING POINT HIGHER THAN N-C7, SEPARATING THE NORMAL HYDROCARBON CONSTITUENTS FROM THE BRANCHED CHAIN, HYDROCARBON CONSTITUENTS OF SAID LOW-BOILING FRACTION, ISOMERIZING SAID NORMAL HYDROCARBON CONSTITUENTS IN AN ISOMERIZATION ZONE IN THE PRESENCE OF HYDROGEN AND A COMPOSITE CATALYST PREPARED BY IMPREGNATING A REFRACTORY, ACIDIC, MIXED OXIDES BASE WITH A HYDROGENATION AGENT, AND PRECONDITIONED BY REDUCTION, FOLLOWED BY OXIDATION AT 650*-750*F., AND REDUCTION WITH HYDROGEN AT 650*-750* F., EMPLOYING THE FOLLOWING REACTION CONDITIONS: TO PRODUCE AN ISOMERIZATION EFFLUENT RICH IN BRANCHEDCHAIN, SATURATED HYDROCARBONS, AND RECOVERING THE BRANCHED-CHAIN HYDROCARBONS FROM SAID ISOMERIZATION EFFLUENT, CATALYTICALLY REFORMING SAID HIGH-BOILING FRACTION IN A REFORMING ZONE IN THE PRESENCE OF HYDROGEN AND A CATALYST CONSISTING ESSENTIALLY OF A NOBLE METAL SELECTED FROM THE GROUP CONSISTING OF PLATINUM AND PALLADIUM SUPPORTED ON A SUITABLE CARRIER AT A TEMPERATURE OF 900*-920* F., UNDER REFORMING CONDITIONS TO PRODUCE A REFORMED REACTION EFFLUENT, SOLVENT EXTRACTING SAID REFORMED EFFLUENT TO PRODUCE A PARAFFINIC FRACTION AND AN AROMATIC FRACTION, FRACTIONATING SAID PARAFFINIC FRACTION TO PRODUCE A DISTILLATE FRACTION CONSISTING ESSENTIALLY OF N-C7 AND LOWER-BOILING HYDROCARBONS AND RESIDUAL FRACTION CONTAINING HYDROCARBONS BOILING ABOVE N-C7, RECYCLING SAID RESIDUAL FRACTION TO SAID REFORMING ZONE, FRACTIONATING SAID DISTILLATE FRACTION TO SEPARATE THE NORMAL HYDROCABON CONSTITUENTS THEREOF FOR TREATMENT IN SAID ISOMERIZATION ZONE, AND RECOVERING THE BRANCHED-CHAIN HYDROCARBONS CONSTITUENTS FROM SAID DISTILLATE FRACTION, AND BLENDING SAID BRANCHEDCHAIN HYDROCARBON CONSTITUENTS FROM SAID LOW-BOILING FRACTION, SAID ISOMERIZATION EFFLUENT, AND SAID DISTILLATE FRACTION WITH SAID AROMATIVE FRACTION TO PRODUCE A HIGH OCTANE NUMBER GASOLINE.