Some Physico-Chemical Studies on Salts of Long Chain Dicarboxylic Acids

Conductimetric studies on the dipotassium salts of acids of the type HOOC(CH2)nCOOH have been made on sebacic acid (K2, n = 8), dodecanedicarboxylic acid (K2, n = 12), and hexadecane dicarboxylic acid (K2, n = 16). The equivalent conductance-concentration curve for K2, n = 16 showed breaks at 11 and at about 33 mM 1.−1; diffusion studies indicated that the formation of small aggregates occurred at 10 mM 1.−1, the aggregates containing two molecules. The second concentration limit was believed to represent either a change in the electrical properties of the solute, or an increase in the amount of aggregate present. Certain tentative deductions about the length of the molecule in solution were made from the diffusion results.