Synthesis of 3,3,3-trifluoropropene telomers and their modification into fluorosurfactants

Abstract

Original fluorinated surfactants based on 3,3,3-trifluoropropene (TFP) as alternatives to perfluorooctanoic acid (PFOA) were synthesized in three to five straightforward steps in good overall yields. First, the radical or thermal telomerization of TFP in the presence of perfluoroisopropyl iodide as the chain transfer agent led to various TFP telomers of different molecular weights. They were further chemically modified into various ionic and non-ionic surfactants. To obtain anionic surfactants, TFP telomers bearing iodine end-group was converted into allylic group on which thioglycolic acid was added under a radical or photochemical process. Non-ionic surfactants were obtained by esterification of the anionic acid with poly(ethylene glycol)monomethylether. Cationic surfactants were obtained by ethylene end-capping of the TFP telomers followed by a nucleophilic substitution by either triethylamine or pyridine. All surfactants showed good inertness to bases and acids, and satisfactory surface properties. They exhibit interesting critical micellar concentration values comparable to that of PFOA (0.06, 4.10, and 3.20 versus 3.00 g L⁻¹).