TWO-STAGE METHOD OF OBTAINING 2-(FLUOROMETHOXY)-1,1,1,3,3,3-HEXAFLUOROISOPROPANE (SEVOFLURANE) Russian patent published in 2009 - IPC C07C41/22 C07C43/12 

FIELD: chemistry.

SUBSTANCE: invention relates to a two-stage method of obtaining 2-(fluromethoxy)- 1,1,1,3,3,3-hexafluoroisopropane (sevoflurane) by reacting 1,1,1,3,3,3-hexafluoroisopropanol-2 with 1,3,5-trioxane or paraformaldehyde and chlorosulphonic acid, with subsequent extraction of 2-(chloromethoxy)- 1,1,1,3,3,3-hexafluoroisopropane (sevoflurane) and its treatment with a fluoride of an alkali metal (aqueous potassium fluoride solution) or ammonium in the presence of triethylamine. The process is carried out at molar ratio of reagents trioxane : 1,1,1,3,3,3-hexafluoroisopropanol-2 : chlorosulphonic acid 1 : 1.8-2.5 : 3-3.5, while stirring at temperature +5-20°C, with subsequent separation and distillation of an organic layer. Treatment with potassium fluoride is done at 72-75°C, with molar ratio of components : sevochlorane : potassium fluoride : triethylamine 1 : 1 : 0.15.

EFFECT: simplification of the process due to prevention of formation of an intermediate aluminium hydrochloride polymer, stable output of products.

7 cl, 3 ex