Solvent extraction and recovery of product and solvent therefrom

Claim 1

IN THE SEPARATION BY DISTILLATION OF COMPONENTS OF A PHASE RESULTING FROM SELECTIVE SOLVENT EXTRACTION OF HYDROCARBON, WHEREIN SAID SELECTIVE SOLVENT CONSISTS OF A PAIR OR INGREDIENTS, ONE OF SAID PAIR BEING MISCIBLE WITH SAID HYDROCARBONS CONTACTED THEREWITH AND THE OTHER OF SAID PAIR BEING IMMISCIBLE WITH SAID HYDROCARBONS AND HAVING A BOILING POINT LOWER THAN THAT OF SAID MISCIBLE SOLVENT, THE IMPROVEMENT COMPRISING INTRODUCING ADDITIONAL IMMISCIBLE COMPONENT INTO THE ZONE OF SAID DISTILLATION IN AN AMOUNT SUFFICIENT TO DISTILL SAID IMMISCIBLE COMPONENT AND SAID HYDROCARBONS FROM SAID ONE AS OVERHEAD, WHILE ADJUSTING THE TEMPERATURE OF THE DISTILLATION ZONE BOTTOMS TO RECOVER THEREFROM A SUBSTANTIALLY HYDROCARBON-FREE SOLVENT PAIR CONTAINING ITS COMPONENTS IN A PROPORTION SUITABLE FOR RE-USE IN SAID SELECTIVE SOLVENT EXTRACTION, SAID PROPORTION BEING SUBSTANTIALLY THE SAME AS THE PROPORTION BEING SUBSTANTIALLY THE SAME AS OF SAID PAIR OF INGREDIENTS.