Photochemical reactions of perfluorodialkyl peroxides with perfluorocycloolefins

Vicinal perfluorodi-t-butoxycycloalkanes and isomers have been prepared in 50 to 70% yields through photochemical reactions of (CF₃)₃COOC(CF₃)₃ with perfluorocycloolefins (c-C₅F₈ and c-C₆F₁₀) under a 200-watt Hg lamp at ?20°C. The two isomers of vic-C₅F₈[OC(CF₃)₃]₂ in 1:4 ratio have been fractionated and identified as cis- and trans-isomers respectively. The three isomers for vic-C₆F₁₀[OC(CF₃)₃]₂ in 1:4:2 ratio have been fractionated and tentatively identified as equatorial-equatorial, axialequatorial and axial-axial respectively.New 2,2′ -perfluorodimethoxycycloalkyls have been prepared in 60 to 80% yields through photolysis of CF₃OOCF₃ with perfluorocycloolefins under a 2500-watt Hg-Xe lamp at ?20°C. The attempted separations of the rotational isomers have been unsuccessful. The need of a strong ultra-violet source for primary perfluorodialkyl peroxide is discussed and the mechanism and the radical chain sequences are presented.Another new synthesis of bis(perfluoro-t-butyl) peroxide [D_{(CF3)3CO-OC(CF3)3} ?34.5 kcal] from (CF₃)₃COF using difluoroamino radicals as the fluoroxy fluorine atoms acceptor is described.