Abstract: Chloromethylated polystyrene was transformed into aminomethylated polystyrene via Gabriel reaction using potassium salt of phthalic imidine as the reagent of nucleophilic substitution. The reaction process for preparing the precursor of aminomethyl polystyrene, phthalimido, methyl polystyrene, via phase-transfer catalysis system was mainly studied. The effects of various factors on the phase-transfer catalysis reaction were examined, and the phase-transfer catalysis mechanism was explored. The experiment results show that the functional transformation reaction of polymers can also be conducted via phase-transfer catalysis successfully. In this study system, the phase-transfer catalysts transfer the anions of phthalic imidine from water phase into organic phase, resulting in more easily performing the nucleophilic substitution reaction between chloromethylated polystyrene and the anions of phthalic imidine, and the successful transform of the chloromethyl groups on the macromolecular chains of chloromethylated polystyrene into methylated phthalimido groups. There are some factors which exert influences on the phase-transfer catalysis reaction, such as the species and the used amount of the catalysts, the polarity of the solvents, the ratio of oil phase to water phase and the reaction temperature. For this reaction system, cetyl trimethyl ammonium bromide is a suited catalyst, and the conversion of chloromethyl groups can reach 87% when toluene is used as solvent at a temperature of 50 ℃ for 8 h.

Key words: Chloromethylated polystyrene, Gabriel reaction, Phase-transfer catalysis, Nucleophilic substitution, Functionalizion of polystyrene