Process for improving the octane number of naphthas

Claim 1

A PROCESS FOR PREPARING HIGH-OCTANE NUMBER FUEL FROM LOW-OCTANE NUMBER NAPHTHA COMPRISING DESULFURIZING AND FRACTIONATING SAID LOW-OCTANE NAPHTHA INTO A HIGHERBOILING FRACTION AND A LOWER BOILING FRACTION, CONTAINING NORMAL PENTANE AND HEXANE AND HAVING AN END POINT OF ABOUT 193* F., CATALYTICALLY REFORMING SAID HIGHER BOILING FRACTION IN THE PRESENCE OF HYDROGEN AT TEMPERATURES OF 900-930* F. AND PRESSURES OF 250-350 LB./SQ. IN., SEPARATING FROM THE REFORMED PRODUCT A LOWER BOILING FRACTION CONTAINING BENZENE, TOLUENE AND XYLENES ADMIXED WITH PARAFFIN HYDROCARBONS, AND A HIGHER BOILING FRACTION, WITH DRAWING THE HIGHER BOILING FRACTION FROM THE SYSTEM, SOLVENT EXTRACTING THE LOWER BOILING REFORMED FRACTION TO SEPARATE A RAFFINATE OF LOW AROMATIC CONTENT AND AN EXTRACT OF HIGH AROMATIC CONTENT, FRACTIONATING SAID REFFINATE INTO FRACTIONS, ONE OF WHICH CONTAINS PREDOMINANTLY C6 AND LIGHTER HYDROCARBONS, AND THE OTHER OF WHICH CONTAINS C7 AND HEAVIER HYDROCARBONS, SUBJECTING THE FRACTION CONTAINING C7 AND HEAVIER HYDROCARBONS TO DEMETHYLATION IN THE PRESENCE OF HYDROGEN AND A CATALYST COMPOSED OF SILICA-ALUMINA CRACKING CATALYST PROMOTED WITH NICKEL MILYBDATE, WHICH IS SELECTIVE FOR THE DEMETHYLATION