高等学校化学学报 ›› 2018, Vol. 39 ›› Issue (5): 983.doi: 10.7503/cjcu20170629

• 物理化学 • 上一篇    下一篇

[Bmim][DBP]离子液体与甲醇分子间的氢键作用机理及在萃取分离混合C4烃/甲醇中的应用

李建伟, 李想, 张傑, 雷志刚   

  1. 北京化工大学化工资源有效利用国家重点实验室, 北京100029
  • 收稿日期:2017-09-20 出版日期:2018-04-19 发布日期:2018-04-19
  • 作者简介:

    联系人简介: 张 傑, 男, 博士, 副研究员, 主要从事新型分离工艺方面的研究. E-mail: zhangjie@mail.buct.edu.cn

  • 基金资助:
    国家自然科学基金(批准号: 21206008)和国家重点研究发展计划项目(批准号: 2017YFC0210905)资助.

Mechanism of the Interaction Between Ionic Liquid [Bmim][DBP] and Methanol for Seperation of Mixed C4/Methanol

LI Jianwei, LI Xiang, ZHANG Jie*, LEI Zhigang   

  1. State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
  • Received:2017-09-20 Online:2018-04-19 Published:2018-04-19
  • Contact: ZHANG Jie
  • Supported by:
    Supported by the National Natural Science Foundation of China(No.21206008) and the National Key Research and Development Program of China(No.2017YFC0210905).

摘要:

研究了用离子液体(ILs)萃取分离混合C4烃(C4)中微量甲醇的过程. 考察了不同组成的离子液体的萃取性能, 发现1-丁基-3-甲基咪唑磷酸二丁酯([Bmim][DBP])具有最佳的萃取性能. 采用量子化学方法, 研究了[Bmim][DBP]与甲醇的作用机理. 结果表明, 在离子液体阴、 阳离子以及离子液体与甲醇之间均存在稳定的氢键, 并且氢键加强了分子间的相互作用. [Bmim][DBP]的阴离子[DBP]-与甲醇中的—OH形成了键长为0.171 nm的氢键, 其相互作用能为-62.08 kJ/mol, 强于其它阴离子与甲醇的相互作用能. 还探讨了[Bmim][DBP]离子液体与混合C4烃的比例、 萃取时间及离子液体循环次数等因素对萃取效果的影响, 结果表明, 当m(ILs)∶m(C4)=1∶2, 于25 ℃萃取60 min时, 萃取率为99.65%, 离子液体循环使用5次后萃取率仍保持稳定.

关键词: 混合C4烃, 离子液体, 甲醇, 萃取机理

Abstract:

In this work, the extractive methanol removal from C4 hydrocarbon using ionic liquids(ILs) as extractants was studied. Firstly, the effect of structure of ionic liquid on extraction process was investigated. The results show that 1-butyl-3-methyl imidazole dibutyl phosphate([Bmim][DBP]) performs the best extraction. According to the selected ionic liquid [Bmim][DBP], quantum chemistry calculation method was used to explain the mechanism between ionic liquid [Bmim][DBP] and methanol. The results show that stable hydrogen bonds not only exist between cation and anion in ionic liquid [Bmim][DBP], but also exist between methanol and ionic liquid [Bmim][DBP]. The hydrogen bonds strengthen the interaction among the molecules. The anion [DBP]- in [Bmim][DBP] and —OH in methanol form a hydrogen bond of 0.1711 nm and the interaction energy is -62.08 kJ/mol. A series of experiments was carried out to determine the effect of ILs/C4 mass ratio, extraction time and recycle times on the performance of ionic liquid [Bmim][DBP]. The results show that the extraction rate reaches 99.65% under the conditions of ILs/C4 mass ratio of 1∶2, extraction time of 60 min, temperature of 25 ℃. Furthermore, the extration rate would not decrease after 5 recycles.

Key words: Mixed C4 hydrocarbon, Ionic liquid, Methanol, Extraction mechanism

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