Direct polycondensation of carboxylic acids and amines catalyzed by 3,4,5-trifluorophenylboronic acid

The effects of 3,4,5-trifluorophenylboronic acid (1) catalyst on the direct polycondensation of various structurally diverse carboxylic acids and amines to aramids, semiaromatic nylons and polyimides were investigated. The structure of the polymers were confirmed by infrared and nuclear magnetic resonance spectroscopies. Among the various solvents and reaction temperatures screened, the desired high molecular weight could be obtained quantitatively as a white solid by heating the reaction mixtures in the presence of only 1 mol % of (1) in a 10:1 mixed solvent of m-terphenyl and N-butyl-2-pyrrolidinone at 300 °C under slow argon flow to remove water.