Collect. Czech. Chem. Commun. 1982, 47, 54-58

Anionic cis-trans isomerization of dialkyl perfluoro(4-methyl-2-pentene)dioates. A non-classical equilibrium dependence

Oldřich Paleta, Jiří Svoboda and Václav Dědek

Department of Organic Chemistry, Prague Institute of Chemical Technology, 166 28 Prague 6


cis-trans-Isomerization of diethyl, diisopropyl, dibutyl and dicyclohexyl perfluoro(4-methyl-2-pentene)dioates (I-IV) was studied in solutions, containing solid potassium fluoride, in the range 20-150°C. The dependence of the cis-trans equilibrium on temperature for the compounds I-IV is within the experimental error identical with that found for the dimethyl ester, i.e. it exhibits and extreme at 40-45°C. This non-classical dependence cannot be described by the van't Hoff equation. The phenomenon is discussed in connection with the so-called cis-effect of fluorine substituents on a double bond.