Preparation and characterization of a number of amine salts of long-chain fatty acids

Summary Eighty-eight amine salts of long-chain fatty acids have been prepared, purified by solvent crystallization, and characterized. Forty-five of these were salts of palmitic acid. The rest included salts of capric, lauric, myristic, stearic, oleic, elaidic, and 12-hydroxystearic acids. A variety of aliphatic, aromatic, and heterocyclic amines, including primary, secondary, and tertiary amines, were investigated. The majority of these gave 1∶1 acid-amine compounds on solvent recrystallization of an equimolar mixture of acid and amine. Some of the amines gave no crystallizable salt, and with others the pure salt could not be obtained by this procedure. Under the same conditions the symmetrical alkyl, substituted alkyl, and aralkyl secondary amines investigated gave crystallizable compounds containg two molecules of fatty acid to one of amine. Molecular compounds of 2-aminopyridine with four molecules of saturated fatty acid were formed by recrystallization starting with a 1 to 4 amine-acid mixture. Surface-tension measurements were made for aqueous solutions of a few of the amine salts. One of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.