METHOD FOR PREPARATION OF PERFLUORO-C-CALCYL HALIDES Russian patent published in 2009 - IPC C07C19/08 

FIELD: chemistry.

SUBSTANCE: invention refers to the method for preparation of perfluoro-C₄-C₈alcyl halides of general formula R_f X, where R_f - perfluoro-C₄-C₈alcyl, X - bromine, iodine, fluorine. The process includes the following stages: a) interreaction of the corresponding perfluoro-C₄-C₈alcane sulphonic-acid fluoride of general formula RfSO₂F with hydrazine in the medium of organic solvent at temperature not less than 50°C with obtaining of the corresponding perfluoro-C₄-C₈alcyl sulphonyl hydrazide with formula R_fSO₂NHNH₂ and b) interreaction of the product obtained in the stage a) with corresponding elemental halogen at heating in the medium of organic solvent at temperature range 90-120°C. The preferential solvent for stages a) and b) is N-methylpirrolidone; the elemental halogen used in the stages b) is bromine or iodine. In latter case the reaction is carried out in the presence of potassium iodate.

EFFECT: high yield and quality of the target product

4 cl, 2 ex