Distillation process for purifying acetone

Claim 1

IN A RECTIFICATION PROCESS FOR OBTAINING A PURE ACETONE FROM CRUDE ACETONE CONTAINTING A CHLORINATED ACETONE WHICH CRUDE ACETONE IS OBTAINED BY DIRECT OXIDATION OF PROPYLENE WITH OXYGEN-CONTAINING GASES IN THE PRESENCE OF AN AQUEOUS CATALYST CONTAINING A NOBLE METAL SALT OF THE PLATINUM GROUP AND HEAVY METAL HALIDES WHICH HEAVY METAL OCCURS IN AT LEAST A LOWER AND A HIGHER VALENCE STAGE AND IS SELECTED FROM AT LEAST ONE METAL SELECTED FROM THE GROUP CONSISTING OF COPPER, IRON, AND CHROMIUM, THE IMPROVEMENT COMPRISING THE STEPS OF: INTRODUCING INTO AN ENRICHMENT ZONE OF A RECTIFICATION ZONE COUNTER-CURRENTLY TO AN ASCENDING VAPOR STREAM OF ACETONE AN AQUEOUS ALKALINE SOLUTION OF AT LEAST ONE HYDROXIDE OF A METAL SELECTED FROM THE GROUP CONSISTING OF ALKALI METALS AND ALKALINE EARTH METALS; COLLECTING THE COUNTER-CURRENTLY DOWN-COMING ALKALINE SOLUTION WITH THE UPPER THIRD OF THE RECTIFICATION ZONE IN A LIQUID COLLECTION ZONE; REMOVING SAID ALKALINE SOLUTION FORM THE RECTIFICATIN ZONE; REINTRODUCING THE ALKALINE SOLUTION INTO THE ENRICHMENT ZONE ABOVE THE COLLECTION ZONE; INTRODUCING INTO A STRIPPING ZONE OF THE RECTIFICATION ZONE CRUDE ACETONE; STRIPPING FROM THE CRUDE ACETONE THE CHLORINATED ACETONE TOGETHER WITH THE ACETONE; COLLECTING THE STRIPPED CHLORINED ACETONE TOGETHER WITH