Acid anhydride to react with impurities in the production of perfluorocarboxylic acids
AssigneePhillips Petroleum Company
InventorsGeir Bjornson, Harold C. Walters
Life of this patent
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Abstract
Perfluorocarboxylic acids are produced by a metathesis reaction between an acid and a perfluoro acid fluoride in the presence of an acid anhydride. The perfluoroacid fluoride can conveniently be produced by electrochemical fluorination of the acyl fluoride co-product of the metathesis step. The acid anhydride present during the metathesis reaction serves the dual function of enhancing the desired reaction to produce the perfluorocarboxylic acid product and to react with impurities and by-products which would otherwise remain with the product and complicate its recovery.
Claims9
In a process comprising contacting under reaction conditions an alkanoic carboxylic acid containing 2 to 10 carbon atoms per molecule, and a perfluorocarboxylic acid fluoride containing 2 to 10 carbon atoms per molecule from an electrochemical fluorination zone to give a perfluorocarboxylic acid and an acyl fluoride, the improvement comprising adding a small amount of an alkanoic acid anhydride to react with impurities, said impurities including at least one of HF, water, and carbonyl fluoride.
Dependencies are inferred from the claim text.