New fluorinated surfactants based on vinylidene fluoride telomers

Straightforward syntheses of vinylidene fluoride (VDF)-containing surfactants, C n F 2 n+1 (VDF) x CH 2CO 2H carboxylic acids, were achieved in four steps and characterized. Such hydrogenofluorinated acids exhibited surface tensions of 19.8 mN m −1 for a surfactant concentration of 5 g L −1, showing similar values as that of commercially available perfluorooctanoic acid (PFOA). [Display omitted] ► The attached manuscript reports the straightforward syntheses of vinylidene fluoride (VDF)-containing surfactants, C n F 2 n+1 (VDF) x CH 2CO 2H carboxylic acids, achieved in four steps, and all intermediates and products were characterized. ► Such hydrogenofluorinated acids exhibited low surface tensions (ca. 19.8 mN m −1 for a surfactant concentration of 5 g L −1) showing similar values as that of commercially available perfluorooctanoic acid (PFOA) regarded as the reference for surfactant endowed with high performance. ► However, PFOA is toxic, persistent and bioaccumulable and possibly the VDF-containing surfactant offer some potential degradation, either via enzymatic or metabolic ways. The synthesis of C n F 2 n+1 (VDF) x –(CH 2) p – ▪ where n = 2, 4; x = 2, 3, 4; p = 0, 1, 2 and VDF and ▪ stand for vinylidene fluoride (VDF) and I, OH, or CO 2H, respectively, are presented. First, the radical telomerization of VDF with C n F 2 n+1 –I to direct low molecular weight-telomers was investigated in various experimental conditions: initiators, temperatures and solvents to favour the formation of C n F 2 n+1 (VDF) x I. Whatever the experimental conditions, it was observed the regioselective radical addition of •C n F 2 n+1 radical onto the methylene site of VDF. Then, ethylenation of these VDF telomers was achieved in the presence of peroxy initiator with a quantitative conversion of the VDF-containing iodide reactants. Chemical change of R F(VDF) xC 2H 4I into R F(VDF)C 2H 4OH occurred in two steps: (i) from a mixture of DMF/water (for which a 6/1 content led to the best conditions); (ii) followed by a basic medium to saponify R F(VDF) x CH 2CH 2OCOH formiate into the corresponding VDF-containing alcohols. Suitable conditions were found to avoid any dehydrofluorination of the VDF telomeric chain. Oxidation of these fluorinated alcohols in the presence of H 2SO 4/CrO 3 mixture led to the corresponding C n F 2 n+1 (VDF) x CH 2CO 2H carboxylic acids. Surface tensions of these VDF-containing carboxylic acids were achieved reaching a value of 19.8 mN m −1 for a surfact