Synthesis, Characterization and Surface Properties of Series Sulfobetaine Surfactants

A series of surface active sulfo-propane betaines and sulfo-butane betaines were synthesized with high yields by the reaction of an appropriate N,N-dimethyl alkylamine with an excess of 1,3-propane sultone and 1,4-butane sultone. The structures were characterized by 1H-NMR spectroscopy and elemental analysis. The micellar properties of these compounds were determined by surface tension methods. Surface tension measurements also provide information about the dependence of the surface tension at the CMC (γcmc), pC20 (negative logarithm of the surfactant molar concentration C20 required to reduce the surface tension by 20 mN/m), the surface excess (Γmax) at air/solution interface, the minimum area per surfactant molecule at the air solution interface (A).