METHOD FOR PRODUCING PERFLUORO-4-(FLUOROSULFONYL)BUTYLVINYL ETHER Russian patent published in 2023 - IPC C07C303/02 C07C309/82 

FIELD: chemistry.

SUBSTANCE: chemical method for the production of perfluorinated vinyl ethers containing a sulfonyl fluoride group, and in particular to a method for producing perfluoro-4-(fluorosulfonyl) butyl vinyl ether, which is a “functional” monomer copolymerizing with tetrafluoroethylene, to obtain polymers intended for the production of ion-exchange membranes with improved performance. The method consists in the fact that 1-perfluorobutene-4-sulfonyl fluoride is oxidized with gaseous oxygen under mild conditions, then catalytic isomerization of the formed 2-(perfluoroxiran-2-yl)perfluoroethane-1-sulfonyl fluoride in an inert solvent medium is carried out to obtain predominantly 4-sulfonyl fluoride perfluorobutanoyl fluoride. Next, the resulting 4-sulfonyl fluoride perfluorobutanoyl fluoride is condensed with hexafluoropropylene oxide in a mixture of polar aprotic solvents, and then the resulting 2-(trifluoromethyl)-3-oxa-7-sulfonyl fluoride perfluoroheptanoyl fluoride is reacted with sodium carbonate in a polar aprotic solvent. After that, thermal decomposition of the resulting sodium salt of 2-(trifluoromethyl)-3-oxa-7-sulfonyl fluoride perfluoroheptanoic acid is carried out with simultaneous distillation of the target product from the reaction zone.

EFFECT: development of a method for producing perfluoro-4-(fluorosulfonyl)butylvinyl ether, which makes it possible to create a method without the use of elemental fluorine, electrochemical fluorination, using commercially available fluorine-containing compounds as a feedstock, as well as carrying out all stages of synthesis and purification in standard process equipment with high selectivity for obtaining intermediate products.

6 cl, 9 ex