Isolation of the 9‐ and 10‐isomers of carboxystearic acid and their polyamidation with hexamethylenediamine

Abstract

AND SUMMARYPhysical properties of the two isomers in 9(10)carboxystearic acid were found to be sufficiently different to permit isolation by recrystallization. Fractions containing carboxystearic acid of high isomeric purity but containing such impurities as stearic and hydroxystearic acids were purified through the nylon salts formed with hexamethylenediamine to obtain each isomer in high functional and isomeric purity. Physical properties were determined for each isomer, its nylon salt, and its polyamide. The different physical properties suggest for substituted dicarboxylic acids the alternating effect in melting points and solubilities shown by the unsubstituted a,~-alkanedioic acids.