Solubilities and Infra-Red characterization of ammonium soaps

Ammonium soaps of saturated fatty acids (C-12-C-18) were prepared and their characteristics in solid state were studied by infrared spectroscopy to ob tain structural information. The solubilities of these soaps in I-butanol, 2-methyl-1-propanol and 2-propanol were found to increase with increasing t emperature (298-323 K) showing a sudden change at the Krafft point (308 K). The apparent heat of solution, Delta H-sol, and entropy of solution, Delta S-sol, were calculated from solubility data and confirm the micellar aggre gation of these soaps in the above-mentioned alcohols.