Fractional distillation of methanol in the presence of an entrainer

Claim 1

PROCESS FOR THE SEPARATION OF METHANOL FROM A MIXTURE THEREOF WITH A LIGHT ALCOHOL SELECTED FROM THE CLASS CONSISTING OF ETHANOL AND ISOPROPANOL BY FRACTIONAL DISTILLATION OF THE SAID MIXTURE IN THE PRESENCE OF AN ENTRAINER, THE MIXTURE ALSO CONTAINING WATER IN A PROPORTION SUCH THAT THE RATIO WATER:WATER+LIGHT ALCOHOL IN THE MIXTURE IS LESS THAN THE RATIO WATER:WATER+LIGHT ALCOHOL IN THE LOWER LAYER OF THE AZEOTROPIC MIXTURE OF LIGHT ALCOHOL, WATER AND ENTRAINER, WHICH PROCESS COMPRISES THE STEPS OF (1) FEEDING THE SAID MIXTURE OF METHANOL, LIGHT ALCOHOL AND WATER WITH AN ENTRAINER SELECTED FROM THE CLASS CONSISTING OF CYCLOHEXANE AND METHYLCYCLOHEXANE TO AN INTERMEDIATE POINT OF A FIRST FRACTIONAL DISTILLATION COLUMN AND FRACTIONALLY DISTILLY THE SAID MIXTURE AND ENTRAINER THEREIN; (2) WITHDRAWING FROM THE TOP OF THE SAID FIRST FRACTIONAL DISTILLATION COLUMN AN AZEOTROPIC MIXTURE OF METHANOL AND ENTRAINER AND CONDENSING THIS AZEOTROPIC MIXTURE; (3) WITHDRAWING PURIFIED LIGHT ALCOHOL FROM THE BOTTOM OF THE SAID FIRST FRACTIONAL DISTILLATION COLUMN; (4) SEPARATING THE CONDENSED AZEOTROPIC MIXTURE FROM STEP (2) INTO TWO LIQUID LAYERS; (5) WITHDRAWING A COMPLEX, LIQUID, WATER-ENRICHED MIXTURE FROM AN INTERMEDIATE POINT OF THE SAID FIRST FRACTIONAL DISTILLATION COLUMN AND SEPARATION THE SAID COMPLEX MIXTURE INTO TWO LIQUID LAYERS; (6) RETURNIANG THE UPPER LIQUID LAYER FROM STEP (4) TO THE UPPER PART OF THE FIRST FRACTIONAL DISTILLATION COLUMN;