Process for the manufacture of perfluoroalkylmethylene-carboxylic acids
AssigneeCiba-Geigy Corporation
InventorHorst Jager
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Abstract
A new process for the manufacture of perfluoroalkylmethylenecarboxylic acids of the formula R.sub.f (CH.sub.2 CF.sub.2).sub.m.sub.-1 CH.sub.2 COOH, wherein R.sub.f is an unbranched or branched perfluoroalkyl radical with 3 to 14 carbon atoms and m is 1 to 3, which comprises reacting perfluoroalkyl iodides of the formula R.sub.f (CH.sub.2 CF.sub.2).sub.m -I with concentrated nitric acid. The compounds are e.g. useful as intermediates for the manufacture of oil- and water repellents; further they can be used themselves e.g. as surface active assistants or as lubricants.
Claims12
A process for the manufacture of perfluoroalkylmethylenecarboxylic acids of the formula
- R.sub.f (CH.sub.2 CF.sub.2).sub.m.sub.-1 --CH.sub.2 --COOH
- wherein R.sub.f is an unbranched or a branched perfluoroalkyl radical with 3 to 14 carbon atoms and m is 1 to 3, which comprises the steps of, (a) reacting perfluoroalkyl iodides of the formula
- R.sub.f --(CH.sub.2 CF.sub.2).sub.m --I
- with nitric acid of 90 to 98% strength in a molar ratio of iodides to nitric acid of 1:1-10, at temperatures of 50.degree. to 150.degree.C and a reaction time of 1 to 20 hours and (b) recovering said perfluoroalkylmethylenecarboxylic acids from the reaction mixture.
Dependencies are inferred from the claim text.