Process for the production of ketene or acetic anhydride from a mixture of acetic acid and formic acid

Claim 1

THE PROCESS FOR THE PRODUCTION OF ACETIC ANHYDRIDE FROM A CRUDE AQUEOUS ACETIC ACID CONTAINING FORMIC ACID WHICH COMPRISES DISTILLING SAID CRUDE AQUEOUS ACID TO REMOVE AS DISTILLATE ESSENTIALLY ALL THE WATER AND A PORTION OF THE FORMIC ACID PRESENT IN SAID CRUDE ACID AND, AS A DISTILLATE SEPARATE FROM THE FIRST MENTIONED DISTILLATE, A PORTION OF THE ACETIC ACID ACCOMPANIED BY FORMIC ACID IN A RATIO (BY WEIGHT) OF NOT SUBSTANTIALLY LESS THAN ONE PART FORMIC ACID TO 20 PARTS ACETIC ACID, HEATING VAPORS OF SAID LAST MENTIONED DISTILLATE CONTAINING ACETIC ACID AND FORMIC ACID UNDER CONDITIONS CRACKING THE ACETIC ACID TO KETENE, WHEREBY THE FORMIC ACID PRESENT IN SAID VAPORS IS SUBSTANTIALLY COMPLETELY DECOMPOSED, ABSORBING IN SUBSTANTIALLY ANHYDROUS ACETIC ACID THE RESULTING KETENE, AND DISTILLING ACETIC ANHYDRIDE FROM THE RESULTING ABSORPTION PRODUCT.