Lubricating oil refining process

Claim 1

IN A PROCESS FOR THE PRODUCTION OF LUBRICATING OIL MATERIAL FROM HEAVY CATALYTICALLY CRACKED GAS OIL AND A VIRGIN LUBRICATING OIL STOCK, THE STEPS COMPRISING (1) EXTRACTING THE VIRGIN LUBRICATING OIL STOCK WITH A SOLVENT SELECTIVE FOR AROMATIC HYDROCARBONS AND SEPARATING AN EXTRACT SOLUTION CONTAINING NEARLY ALL OF THE POLYCYCLIC AROMATICS AND RESINS AND A LARGE PORTION OF THE MONOCYCLIC AROMATICS AND PRIMARY RAFFINATE ENRICHED IN PARAFFINIC HYDROCARBONS, (2) EXTRACTING THE CRACKED GAS OIL WITH SAID EXTRACT SOLUTION AND SEPARATING A SECOND RAFFINATE ENRICHED IN PARAFFINIC HYDROCARBONS AND CONTAINING A LARGE PORTION OF THE MONOCYCLIC AROMATIC HYDROCARBONS PRESENT IN THIS SECOND EXTRACTION SYSTEM AND (3) SUBSEQUENTLY BLENDING AT LEAST A PORTION OF THE SECOND RAFFINATE WITH THE PRIMARY RAFFINATE TO OBTAIN A BLENDED PRODUCT OF GREATER OXIDATIVE STABILITY AND ENHANCE MONOCYCLIC AROMATIC CONTENT COMPARED TO THE OXIDATIVE STABILITY AND MONOCYCLIC AROMATIC CONTENT OF THE PRIMARY RAFFINATE.