Patent ID: 8044247

Claim:
A process for the preparation of fluoromethyl 2,2,2-trifluoro-1-(trifluoromethyl)ethyl ether (sevoflurane) comprising the following steps: (i) reacting hexafluoroisopropanol (HFIP) with: a formaldehyde equivalent selected from the group consisting of paraformaldehyde and 1,3,5-trioxane; a chlorinating agent selected from the group consisting of oxalyl chloride, sulfuryl chloride and thionyl chloride; and a concentrated or fuming sulfuric acid, wherein the reactants are combined in a way selected from the group consisting of a) adding the sulfuric acid to a mixture of HFIP, formaldehyde equivalent and chlorinating agent; and b) adding the chlorinating agent to a mixture of HFIP, formaldehyde equivalent and sulfuric acid; and c) adding the HFIP to a mixture of the formaldehyde equivalent, sulfuric acid and chlorinating agent, thereby generating chlorosulfonic acid and chloromethylating the HFIP in the same pot to form sevochlorane; and (ii) reacting sevochlorane with an alkali metal fluoride, or with a linear or branched chain tetra-alkyl, quaternary ammonium fluoride in the presence of a sub-stoichiometric quantity of an alkali metal iodide, or of a linear or branched chain tetra-alkyl, quaternary ammonium iodide, to form sevoflurane.