Process for alkyl perfluoro(4,7-dioxa-5-methyl-8-fluoroformylnonanoate

Claim 1

In a process for preparing a product compound of the formula ##STR11## where R is alkyl of 1-6 carbon atoms, wherein a reactant of the formula ##STR12## where R is as defined above is contacted with hexafluoropropylene oxide in the presence of a fluoride compound which provides fluoride ion catalyst, the improvement comprising contacting said reactant with hexafluoropropylene oxide and said catalyst in the presence of a medium consisting essentially of two components, component A being 50 to 98% by volume of an aprotic liquid dinitrile in which methyl perfluoro (4-oxa-5-fluoroformylhexanoate) dissolves to the extent of less than 10 g/100 g of A at 20° C. or tetramethylenesulfone, and component B being 50 to 2% by volume of an aprotic liquid glyme, lactone or mononitrile in which said fluoride compound is soluble to the extent of at least 0.001% by weight at 20° C. and in which methyl perfluoro(4-oxa-5-fluoroformylhexanoate) dissolves to the extent of at least 10 g/100 g of B at 20° C., separating a heavier phase which contains said product compound from a lighter phase, and separating said product compound from said heavier phase.