Surfactants having polyfluoroalkyl chains. II. Syntheses of anionic surfactants having two polyfluoroalkyl chains including a trifluoromethyl group at each tail and their flocculation-redispersion ability for dispersed magnetic particles in water

Article abstract of DOI:10.1016/0022-1139(94)03111-C

Anionic surfactants having two polyfluoroalkyl chains per molecule, i.e. the sodium salt of bis(1H,1H,2H,2H-heptadecafluorodecyl)-2-sulfosuccinate, CF3(CF2)7(CH2)2OCOCH2CH(SO3Na)COO(CH2)2(CF2)7CF3, the sodium salt of bis(1H,1H,2H,2H-tridecafluoro-octyl)-2-sulfosuccinate, CF3(CF2)5(CH2)2OCOCH2CH(SO3Na)COO(CH2)2(CF2)5CF3, and the sodium salt of bis(1H,1H,2H,2H-nonafluorohexyl)-2-sulfosuccinate, CF3(CF2)3(CH2)2OCOCH2CH(SO3Na)COO(CH2)2(CF2)3CF3, have been prepared from maleic anhydride, the corresponding alcohols possessing a polyfluoroalkyl chain and sodium hydrogen sulfite.The flocculation and redispersion abilities of these surfactants for dispersed magnetic particles in water have been examined to investigate the effect of the chain length.It was found that this ability was enhanced by an increase in the chain length.The contact angles for water for pelleted surface-modified magnetite have been measured.In order to compare this ability and the contact angles, data for other fluorinated surfactant have been obtained.The Krafft point, the surface tension and the pNa of the aqueous surfactant solutions have also been measured. - Keywords: Anionic surfactants; Syntheses; Flocculation-redispersion ability; Magnetite particles; Contact angles; Krafft points; Surface tension