Abstract: In order to study the performance of an amphoteric resin with hydroxyl group and nitrogen-containing heterocycle used for the separation of succinic acid (SA), a weak acid-weak base resin, shortly called 4-VMVH resin, the copolymerization of 4-vinylpyridine with methyl acrylate and vinyl acetate, was prepared, then the physicochemical property, performance and adsorption mechanism of the resin was explored. The results indicated that more meso- and micro-pores and less macro-pore were determined inside the resin, and the adsorption of SA on the resin was an exothermic process and could be described by Freundlich model. The distribution of adsorption site on the resin was inhomogeneous, and the isosteric adsorption enthalpy of the resin decreased with increasing the fractional loading of SA. The total acid-base exchange capacity and the hydroxyl group content of the 4-VMVH01 resin were 4.607 mmol/g and 114.21 mg KOH/g and higher than that of the 2-VMVH resin. Moreover, the resolution of SA and acetic acid (AcOH) was 0.92 while the recovery rate of SA reached to 84.67% at a ratio of the column height to its diameter of 15/1 with only hot water as eluent, and the reusability of the 4-VMVH resin basically remained constant. The interaction energy between the heterocyclic N atom and the carboxyl H atom of SA was higher than that between the heterocyclic N atom and the carboxyl H atom of AcOH. The interaction energies between hydroxyl O atom and the carboxyl H atoms of SA and AcOH were respectively -26.531 kJ/mol and -25.094 kJ/mol, which belonged to the hydrogen-bonding adsorption, and therefore the retention force of SA on the 4-VMVH resin was stronger than that of AcOH.

Key words: 4-VMVH resin, weak acid-weak base type, hydroxyl group, succinic acid, separation performance

摘要： 为了探讨带有羟基及含氮杂环两性树脂绿色分离丁二酸(SA)的性能，设计制备了4-乙烯基吡啶、丙烯酸甲酯及乙酸乙烯酯共聚的弱酸弱碱型4-VMVH树脂，研究了树脂的理化性质、分离丁二酸的性能及其作用机制。结果表明，4-VMVH型树脂内有较多的介孔和微孔，大孔较少；树脂吸附SA为放热反应，符合Freundlich模型；树脂表面能量为非均匀性，且随着SA负载量的增加，树脂表面的?H值减小；部分4-VMVH树脂骨架上酸碱的总交换容量和羟基含量高于2-VMVH树脂。以热水为洗脱剂，4-VMVH01树脂层高径比为15/1时，SA和乙酸(AcOH)的分离度为0.92，SA回收率达到了84.67%，树脂的复用性能稳定。含氮杂环上N与SA羧基上H的作用能大于其与AcOH羧基上H的作用能，羟基上O与SA和AcOH羧基上H的作用能分别为-26.531和-25.094 kJ/mol，属于氢键吸附范畴，4-VMVH型树脂对SA的吸附作用力强于AcOH。

关键词: 4-VMVH树脂, 弱酸弱碱型, 羟基, 丁二酸, 分离性能