Isomerization of hydrocarbons

Claim 1

THE PROCESS FOR ISOMERIZING A HYDROCARBON FRACTION CONTAINING A SATURATED NORMAL PARAFFIN AND A SATURATED MONOCYCLOPARAFFIN WHOSE SEPARATION BY FRACTIONATION IS DIFFICULT BECAUSE OF THEIR CLOSELY ADJACENT BOILING POINTS, WHICH COMPRISES PASSING SAID HYDROCARBON FRACTION INTO A DISTILLATION ZONE HAVING A RECTIFYING SECTION AND A STRIPPING SECTION, ISOMERIZING NORMAL PARAFFIN TO AN ISOPARAFFIN AND CYCLOPARAFFIN TO AN ISOMERIC CYCLOPARAFFIN IN THE PRESENCE OF AN ISOMERIZATION CATALYST COMPRISING A FRIEDEL-CRAFTS METAL HALIDE, INTRODUCING ABOVE THE POINT OF FEED OF SAID HYDROCARBON FRACTION INTO SAID RECTIFYING SECTION INDEPENDENTLY A PROMOTING AMOUNT OF HYDROGEN CHLORIDE AND INDEPENDENTLY BELOW SAID FEED TO SAID STRIPPING SECTION A PROMOTING AMOUNT OF HYDROGEN CHLORIDE AND MAINTAINING A HIGHER CONCENTRATION OF HYDROGEN CHLORIDE IN SAID RECTIFYING SECTION THAN IN SAID STRIPPING SECTION, MAINTAINING A TEMPERATURE IN SAID DISTILLATION ZONE BETWEEN ABOUT 150 AND ABOUT 450* F., MAINTAINING A PRESSURE IN SAID DISTILLATION ZONE BETWEEN ABOUT 25 AND ABOUT 350 POUNDS PER SQUARE INCH GAGE, PASSING ISOPARAFFIN UPWARD IN THE VAPOROUS STATE AND ISOMERIC CYCLOPARAFFIN DOWNWARD IN THE LIQUID STATE, RECOVERING ISOPARAFFIN AS AN OVERHEAD PRODUCT, AND RECOVERING ISOMERIC CYCLOPARAFFIN AS A BOTTOM PRODUCT FROM SAID DISTILLATION ZONE.