PERFLUOROCARBOXYLIC ACID SALT AND SYNTHESIS METHOD THEREOF Russian patent published in 2012 - IPC C07C51/41 C07C59/135 C08F2/26 C08F14/26 C08F114/26 

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of producing a perfluorocarboxylic acid salt, having iron content of at most 10 ppm by weight, and having formula (1), where R^F denotes a C_1-10-univalent perfluorinated organic group, each of X¹ and X² independently denotes a fluorine atom or a trifluoromethyl group, k is an integer not less than 1, and M⁺ denotes an ammonium ion or an alkyl-substituted ammonium ion, which involves a step for hydrolysis of a compound (2) of formula (2) with water using reaction apparatus equipped with a reactor in which at least its inner surface is made from a fluoropolymer, where the amount of the water used ranges from 0.9 to 1.2 mole per mole of compound (2), wherein content of HF in the reaction product is at most 0.1 wt %, and the obtained reaction product is distilled for purification purposes, thereby obtaining a compound (3) of formula (3), and a step for formation of a salt of compound (3) in order to obtain a salt of perflurocarboxylic acid, where R^F, X¹, X² and k are the same as in formula (1). The method enables to obtain a perfluorocarboxylic acid salt with excellent capacity to reduce surface tension, which can be used to produce fluorinated polymers without colouration of polymers under the effect of high temperature. R^p(OCF(X¹)CF₂)_k-1OCF(X²)COO^-M⁺ (1) R^p(OCF(X¹)CF₂)_k-1OCF(X²)COF (2) R^F (OCF(X¹)CF₂)_k-1OCF(X²)COOH (3).

EFFECT: improved method.

7 cl, 2 tbl, 18 ex