Synthesis of Imide Dicarboxylic Acid

N-(4-carboxyphenyl) trimellitimide and N-(2-carboxymethyl) trimellitimide, the reactive intermediates for polyamide imide, were synthesized by the reaction of trimellitic anhydride with glycine and p-aminobenzoic acid, respectively. The structures of the products were confirmed by 1H-NMR and IR, and the influences of reaction time, solvent amount, toluene amount and mole ratio of raw materials were also investigated in the paper. It is concluded that the optimal process conditions of synthesizing N-(4-carboxyphenyl) triellitimide are that n(PABA): n(TMA) = 1.05, the concentration of trimellitic anhydride in dimethyl acetamide is 1.1 mol?L?1, the volume ratio of toluene and solvent is 0.5, and the reactive time is 5 h. The optimal process conditions for synthesizing N-(2-carboxymethyl) trimellitimide are that n(Gly):n(TMA) = 0.95, the concentration of trimellitic anhydride in dimethyl formamide is 2.5 mol?L?1, the volume ratio of toluene and solvent is 0.875, and the reactive time is 2.5 h.