Reaction of carbonyl fluoride with fluorine in the presence of various fluorides as catalysts

Abstract

The fluorides KF, RbF and CsF have been known to serve as catalysts for the reaction CF 2O + F 2→ CF 3OF. The list of catalysts for this process has now been enlarged to include NaF, MgF 2, CaF 2, SrF 2, BaF 2 and LaF 3. Lithium fluoride and thorium fluoride also give CF 3OF but are less active. Perhaps the substances CsF·HF, KAgF 4 and NiF 2 should be included in this list. Silver fluoride, usually as a mixture of AgF 2 with AgF, has been known to catalyze the reaction of CF 2O with F 2 to give both CF 3OF and CF 3OOCF 3. The proportion of the latter in the mixture of products increases with decreasing temperature. At 25°, the reaction is slow and the yield of CF 3OOCF 3 is very high. It has now been shown that TIF 3 behaves like silver fluoride. It has also been shown that many other fluorides of metals give higher yields of CF 3OOCF 3 than of CF 3OF but require higher temperatures than AgF 2 (100- ca. 150°) to be effective. Various possible mechanisms for these catalytic processes are discussed.