The a-sulfonation of pelargonic,stearic, and substituted stearic acids

Direct sulfonation of higher fatty acids with sulfur trioxide or chlorosulfonic acid, without use of solvent, is possible, but the product must then be isolated as the sodium salt. Use of a chlorinated solvent permits isolation of the α-sulfo acid. Sulfonation with dioxane sulfur trioxide in place of sulfur trioxide gave a nearly colorless α-sulfostearic acid. Substituted stearic acids derived from oleic or elaidic acids (phenyl-, 9,10-dichloro-, and 9,10-dihydroxystearic acids) were α-sulfonated with dioxane sulfur trioxide. Solubility, detergent, and surface-active properties were examined and related to structure. The surface-active properties of sodium α-sulfopelargonic acid are not very evident, but the octyl ester, with a much lower critical micelle concentration (0.08% compared to 1.00%), was found to be a very efficient wetting agent. Presented at the fall meeting, American Oil Chemists’ Society, New York, N. Y., October 17–19, 1960. Eastern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.