Synthesis and Characterization of Novel Aryl Alkyl Sulfonates Based on Nonylphenol

A series of nonylphenol-substituted alkyl sulfonates (C x NPAS, x = 8, 10, 12, 14, 16) with two hydrocarbon chains and two different hydrophilic groups has been synthesized from α-olefins and nonylphenol. The respective products have a “pseudo-gemini” surfactant structure. The structures of the C x NPAS have been characterized by IR, UV, 1 H nuclear magnetic resonance, electrospray ionization mass spectrometry, and elemental analysis. The effects of carbon chain length of the obtained surfactants on properties such as the critical micelle concentrations (CMC) in aqueous solutions, surface tension at the CMC ( γ CMC ), and efficiency of adsorption at the water/air interface ( pC 20 ) have been determined. The γ CMC of the surfactants first decreased and then increased with increasing length of the carbon chain x , and reached a minimum of 29.25 mN/m at x = 10, which is much lower than that of α-olefin sulfonate (AOS) (33.52 mN/m). The CMC decreased and pC 20 increased with increasing x . The introduction of the hydroxyl group is responsible for multiple molecular conformations at the water/air interface and leads to a greater molecular area A min and smaller Γ max than those of AOS.