Synthesis and surface properties of chemodegradable anionic surfactants: Sodium carboxylates of cis‐1,3‐dioxane derivatives

Abstract

AbstractThe 2‐n‐alkyl‐5‐carboxy‐5‐methyl‐1,3‐dioxanes were obtained in good yield from the reaction of aliphatic aldehydes with 2,2‐bis(hydroxymethyl)propionic acid in dichloromethane solution, catalyzed by p‐toluenesulfonic acid monohydrate. Nuclear magnetic resonance analysis indicated that they were pure cis‐isomers with the axial configuration of the carboxylic group at the C‐5 carbon atom of the 1,3‐dioxane ring. The acids were converted, with retention of the configuration, to their sodium salts by reaction with sodium methoxide or sodium hydroxide in methanol. The physicochemical properties of the acids and sodium salts, as well as their surface properties at the aqueous solution‐air interface, were determined. Critical micelle concentration, surface excess concentration, surface area demand per molecule of sodium salts at the monomolecular surface layer, and standard free energy of micellization were determined based on surface tension measurements.