Process for improving alcohol quality

Claim 1

IN THE FINISHING OF A CRUDE ALCOHOL FORMED BY HYDRATION OF C2 TO C4 OLEFIN IN WHICH CHARACTERISTIC LOW-BOILING IMPURITIES INCLUDE ETHER AND HIGHER-BOILING IMPURITIES INCLUDING ALDOL, UNSATURATED ALDEHYDE, POLYMER, AND SULFUR COMPOUNDS, THE IMPROVEMENT WHICH COMPRISES INITIALLY FRACTIONALLY DISTILLING THE CRUDE ALCOHOL DILUTED WITH ABOVE 25 VOLUME PERCENT OF WATER TO DISTILL THE LOW-BOILING IMPURITIES INCLUDING THE ETHER AS A LIGHT FRACTION AND TO DISTILL THE ALCOHOL WITH ABOUT AN AZEEOTROPIC AMOUNT OF WATER AS AN INTERMEDIATE FRACTION TAKEN AS A SIDE STREAM FROM AN AQUEOUS BOTTOMS PORTION CONTAINING A MAJOR PROPORTION OF THE WATER WITH SAID HIGH-BOILING IMPURITIES DISSOLVED THEREIN, PASSING SAID INTERMEDIATE AQUEOUS ALCOHOL AZEOTROPE FRACTION FREED OF THE LOW-BOILING AND HIGHER BOILING IMPURITIES TO A WATER EXTRACTIVE DISTILLATION ZONE, DISTILLING A REMAINING SMALL AMOUNT OF LOW AND HIGHERBOILING IMPURITIES FROM THE ALCOHOL DILUTED BY WATER IN SAID EXTRACTIVE DISTILLATION ZONE, THEN RECTIFYING THE ALCOHOL FROM DILUTE AQUEOUS BOTTOMS WITHDRAWN FROM THE EXTRACTIVE DISTILLATION ZONE.