PROCESS FOR THE PRODUCTION OF FLUOROCARBOXYLIC ACID ANHYDRIDES

摘要

Disclosed is process for the production of symmetrical fluoro-substituted anhydrides from mixed or unsymmetrical anhydrides, i.e., wherein the two carboxylic acid acyl groups of the anhydrides are different, by subjecting an unsymmetrical anhydrides to reactive distillation to produce a lower boiling product comprising a symmetrical fluorocarboxylic acid anhydride and a higher boiling product comprising a second symmetrical anhydride. The process is particularly useful for the coproduction of trifluoroacetic anhydride (TFAA) and acetic anhydride (Ac2O) from ketene and trifluoroacetic acid wherein ketene and trifluoroacetic acid (TFA) are reacted to produce a mixed anhydride, acetyl trifluoroacetate (Ac-TFA), which then is subjected to reactive distillation to produce a vapor product comprising TFAA and a liquid product comprising Ac2O.