采用相转移催化法制备苯二甲酰亚胺基甲基聚苯乙烯

以邻苯二甲酰亚胺钾盐为亲核取代试剂, 采用相转移催化体系通过Gabriel反应, 将氯甲基聚苯乙烯转变为苯二甲酰亚胺基甲基聚苯乙烯, 考察了各种因素对相转移催化反应的影响规律, 探讨了相转移催化机理. 结果表明, 采用相转移催化体系, 相转移催化剂将邻苯二甲酰亚胺负离子从水相中转移至油相, 与氯甲基聚苯乙烯发生亲核取代, 顺利地将氯甲基聚苯乙烯大分子链上的氯甲基转变成了甲基化的苯二甲酰亚胺基, 成功地实现了高分子的功能化转变. 影响相转移催化反应的主要因素有催化剂种类与用量、溶剂的极性、油相与水相比例及温度等. 当以十六烷基三甲基溴化铵为催化剂且以甲苯为有机相时, 反应效果最佳, 反应温度为50 ℃时, 反应8 h氯甲基的转化率可达到87%.

Synthesis of Phthalimido Methyl Polystyrene Using Chloromethylated Polystyrene as Start Substance via Phase-transfer Catalysis

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.