Extractive distillation of ethanol contaminated by n-propanol

Claim 1

THE METHOD OF SEPARATING PURIFIED ETHANOL FROM A MIXTURE CONTAINING AS CONTAMINANTS N-PROPANOL WITH NEUTRAL NON-ALCOHOL ORGANIC COMPOUNDS BOILING IN THE RANGE OF 20* C. TO 150* C., WHICH COMPRISES CONTINUOUSLY INTRODUCING A FEED STREAM OF THE MIXTURE INTO A MID-SECTION OF A FRACTIONAL DISTILLATION ZONE, SUPPLYING ADEQUATE WATER AT A TOP PLATE OF SAID ZONE TO MAINTAIN A WATER CONCENTRATION BETWEEN 95 AND 99 MOLE PER CENT WITH A DIMINISHING CONTENT OF N-PROPANOL IN INTERNAL REFLUX DESCENDING FROM THE TOP PLATE REMOVING AQUEOUS VAPORS OF SAID CONTAMINANTS THAT PASS ABOVE SAID TOP PLATE OF THE FRACTIONAL DISTILLATION, CONDENSING A PORTION OF SAID AQUEOUS VAPORS INTO AN AQUEOUS CONDENSATE AND REFLUXING THIS AQUEOUS CONDENSATE BACK TO THE TOP PLATE OF SAID FRACTIONAL DISTILLATION ZONE TO FORM PAR OF THE 95 TO 99 MOLE PER CENT WATER CONTENT OF LIQUIDS AT THE TOP OF THE FRACTIONAL DISTILLATION ZONE, STRIPPING OUT SAID CONTAMINANTS FROM THE RESIDUAL INTERNAL REFLUX PASSING DOWN THROUGH STRIPPING SECTION OF THE FRACTIONAL DISTILLATION ZONE BELOW SAID MID-SECTION, AND WITHDRAWING FROM A BOTTOM PART OF THE FRACTIONAL DISTILLATION ZONE THE ETHANOL FREED OF SAID CONTAMINANTS.