Purification of synthetic glycerol

Claim 1

A PROCESS FOR PURIFYING CRUDE,DILUTE AQUEOUS GLYCEROL PRODUCED VIA HYDROXYLATION OF ALLY ALCOHOL WHICH COMPRISES (1) CONCENTRATING SAID GLYCEROL SOLUTION BY EVAPORATION OF WATER THEREFROM UNDER ACIDIC CONDITIONS AND UNDER AN INITIAL PRESSURE OF FROM ABOUT 40 TO ABOUT 175 POUNDS UNTIL THE WATER CONTENT IS REDUCED TO NOT MORE THAN ABOUT 35% BY WEIGHT, (2) FLASHING OFF THE BULK OF THE GLYCEROL FROM THE CONCENTRATED SOLUTION WHILE MAINTAINING THE LIQUID UNDER ALKALINE CONDITION AT A PH OF FROM ABOUT 9 TO ABOUT 12, (3) REDISTILLING THE GLYCEROL,CONTAINING BOTTOMS OF SAID FLASHING OPERATION UNDER ALKALINE CONDITIONS TO SUBSTANTIALLY REMOVE THE REMAINING GLYCEROL, (4) DISTILLING THE GLYCEROL TAKEN OVERHEAD IN SAID FLASHING AND REDISTILLATION OPERATIONS (2) AND (3) UNDER REDUCED PRESSURE TO SEPARATE LOWER BOILING IMPURITIES THEREFROM, (5) DISTILLING THE OVERHEAD PRODUCT OF SAID DISTILLATION (4) UNDER REDUCED PRESSURE UNDER ACIDIC CONDITIONS TO RECOVER GLYCEROL AS BOTTOM PRODUCT FROM VAPORIZED ORGANIC IMPURITIES, AND (6) DISTILLING THE BOTTOM PRODUCT OF SAID DISTILLATION Z(4) UNDER REDUCED PRESSURE TO TAKE OFF GLYCEROL FROM HIGHER BOILING IMPURITIES UNDER ALKALINE CONDITIONS.