Preparation, surface-active properties, and antimicrobial activities of bis-quaternary ammonium salts from amines and epichlorohydrin

A series of new cationic surfactants, bis-quaternary ammonium salts, were prepared from tert-alkylamine and a product of the reaction of epichlorohydrin with decyl- and dodecylamine, and their surface-active properties were measured. Specifically, the critical micelle concentration (CMC), effectiveness of surface tension reduction (gamma(CMC)), surface excess concentration (Gamma), area per molecule at the interface (A), and standard free energies of adsorption (Delta G(ads)degrees) and of micellization (Delta G(mic)degrees) were determined. All these surfactants showed good water solubility and low CMC, more than one order of magnitude lower than those of corresponding monoalkylammonium salts. They also showed good foaming properties but worse wetting capabilities. Many of these compounds had antimicrobial activities against gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) and yeast (Candida albicans), but they were not active against molds.