THE STRUCTURE OF ALUMINUM DI- AND TRI-SOAPS

Confirmation of the existence of aluminum trilaurate has been obtained by using infrared absorption to follow the course of the reactions of trimethylaluminum and aluminum isopropoxide with lauric acid. The trisoap is shown to exist as micelles of high molecular weight in solution, the size decreasing on dilution or elevation of temperature. On hydrolysis to the disoap, hydrogen bonding does not appear to play a significant role in the formation of polymer structures. Coordination of carboxylate groups with aluminum is shown to be a major feature of the structure of both tri- and di-soaps. Spectral assignments in the 6.0 to 6.4 μ region have been made for various types of inter- and intra-molecular coordination. The effects of dilution, hydrolysis, and hydrochlorination of aluminum trilaurate in solution have been assessed by viscosity, light-scattering, and infrared measurements.