Perfluoroalkyl derivatives of nitrogen. Part XXVIII. Reaction of trifluoronitrosomethane with trifluoroacryloyl fluoride: a route to perfluoro-(3-azabut-2-enoyl) fluoride and hence trifluoromethyl isocyanide

Abstract

Trifluoronitrosomethane combines with trifluoroacryloyl fluoride to yield a 1 : 1 alternating copolymer, mainly with structure [–N(CF₃)·O·CF₂·CF(COF)-–]_n, and a small amount of material believed to be perfluoro-(4-fluorocarbonyl-2-methyl-1,2-oxazetidine), CF₃·[graphic omitted]·O·CF(COF)·[graphic omitted]F₂. Pyrolysis of the copolymer gives, inter alia, perfluoro-(3-azabut-2-enolyl) fluoride, which is hydrolysed to oxalic acid by aqueous base. Pyrolysis of the butenoyl fluoride over potassium fluoride causes α-elimination of carbonyl fluoride, to give trifluoromethyl isocyanide. The isocyanide isomerises to trifluoromethyl cyanide when heated, reacts with mercuric oxide to yield trifluoromethyl isocyanate, and readily yields a polymer that possibly has the structure [–C(:N·CF₃)·C(:N·CF₃)--]_n.