Monodisperse perfluoro-polyethoxylated amphiphilic compounds with two-chain polar head - preparation and properties
摘要:
Monodisperse new surfactant molecules with a two-chain polyoxyethylene (EO) hydrophilic head and a per fluoroalkyl hydrophobic moiety linked together through an amide bond are synthesized by methods allowing large-scale production. Surface tension measurements (gamma-approximately-20 mN.m-1) show slow organization of the surfactant film at the water/air interface for longer fluorocarbon tail. Values of critical micellar concentrations and comparisons with monosubstituted amide surfactants are consistent with a high hydrophilicity of the amide function, a small influence of branching over hydrophilicity, and a hydrophobicity of each CF2 unit equivalent to 1.7 methylenes (in the analogous hydrogenated surfactants).
Synthesis of 2H,2H-perfluoroalkyl and 2H-perfluoroalkenyl carboxylic acids and amides
摘要:
An efficient and convenient procedure for the synthesis of 2-perfluoroalkyl ethanoic acids by direct oxidation of 2-perfluoroalkyl ethanols with Jones' reagent (CrO3/H2SO4) is described. Treatment of the acids with aqueous sodium hydroxide gave 3-perfluoroalkyl, 3-fluoro-2,3-propenyl carboxylic acids which may be used for the preparation of the corresponding chlorides and amides.