Synthesis of novel lipophilic and/or fluorophilic ethers of perfluoro- tert-butyl alcohol, perfluoropinacol and hexafluoroacetone hydrate via a Mitsunobu reaction: Typical cases of ideal product separation

Abstract

Fluorophilic ethers having the structure RC(CF 3) 2O(CH 2) 3C n F 2 n + 1 are obtained in high yields, when F- tert-butyl alcohol (R = CF 3), F-acetone hydrate (R = O(CH 2) 3C n F 2 n + 1 ), F-pinacol (R = C(CF 3) 2O(CH 2) 3C n F 2 n + 1 ) are reacted with 3-perfluoroalkyl-1-propanols (C n F 2 n + 1 (CH 2) 3OH, n = 4, 6, 8, 10) in a Mitsunobu reaction (Ph 3P/DIAD [ i-PrO 2CN = NCO 2Pr- i]/ether). The parent lipophilic ethers with the structure of (CF 3) 3CO(CH 2) 3C n H 2 n + 1 were prepared analogously using the corresponding fatty alcohols and F- tert-butyl alcohol. To achieve ideal separations, products were transferred to orthogonal phases relative to the other reaction components using fluorous extraction, fluorous solid–organic liquid filtration, or steam-distillation. Selected physical properties including melting and boiling point, together with fluorous partition coefficients of these ethers were determined and the figures obtained were qualitatively analyzed using relevant thermodynamic theories. Some of these ethers are liquids with rather low freezing points and are miscible with fluorocarbon solvents.