Polyfluoro diethyl and ethyl methyl ethers: their preparation using cobalt (III) fluoride and potassium tetrafluorocobaltate (III) and their dehydrofluorination

Abstract

Diethyl ether has been fluorinated with CoF 3 to yield a mixture from which dl -threo and -erythro 1,2-difluoroethyl 1,2,2-trifluoroethyl ether, dl and meso bis(1,2,2-trifluoroethyl) ether and dl-1,1,2,2-tetrafluoroethyl 1,2,2-trifluoroethyl ether were isolated. Fluorination with KCoF 4 at ca 200° afforded ethyl 1,2,2-trifluoroethyl ether as the sole isolable product; at higher temperatures some of the above ethers were formed. Similar fluorination with CoF 3 of methyl ether afforded 1,2,2-trifluoroethyl methyl ether, 1,2,2-trifluoromethyl ether, 1,2,2-trifluoroethyl difluoromethyl ether and 1,1,2,2-tetrafluoroethyl methyl ether; with KCoF 4 1,2,2-trifluoroethyl methyl ether was the sole product. Dehydrofluorination, using fused potassium hydroxide, of either isomer of bis(1,2,2-trifluuoroethyl) ether gave a mixture of (E,Z,) and (Z,Z) bis(1,2-difluorovinyl) ethers and (E) and (Z) 1,2,2-trifluorethyl 1,2-difluorovinyl ethers. Similarly, 1,1,2,2-tetrafluoroethyl 1,2,2-trifluoroethyl ether yielded (E) and (Z) 1,1,2,2,-tetrafluoroethyl 1,2-difluorovinyl ether in the ratio 1:4. Dehydrofluorination of 1,2,2-trifluoroethyl fluoromethyl ether yielded (E) and (Z) fluoromethyl 1,2-difluorovinyl ethers with a trace of fluoromethyl 2,2-difluorovinyl ether.