波谱学杂志 ›› 2017, Vol. 34 ›› Issue (2): 156-163.doi: 10.11938/cjmr20170204

• 研究论文 • 上一篇    下一篇

离子液体热分解机理的原位变温多核核磁共振研究

李森, 郑俊鹏, 郭鸣明   

  1. 中国石油化工股份有限公司北京化工研究院, 北京 100013
  • 收稿日期:2016-05-03 修回日期:2017-04-17 出版日期:2017-06-05 发布日期:2017-06-05
  • 通讯作者: 李森,Tel:010-59202620,E-mail:lisen01.bjhy@sinopec.com;郭鸣明,Tel:010-59202187,E-mail:guomm.bjhy@sinopec.com. E-mail:lisen01.bjhy@sinopec.com;guomm.bjhy@sinopec.com
  • 基金资助:
    中国石化基础性前瞻性研究资助项目 (14-16ZS0402).

In Situ Variable-Temperature Multi-Nuclear NMR Studies of the Thermal Decomposition Mechanism of Ionic Liquid

LI Sen, ZHENG Jun-peng, GUO Ming-ming   

  1. SINOPEC Beijing Research Institute of Chemical Industry, Beijing 100013, China
  • Received:2016-05-03 Revised:2017-04-17 Online:2017-06-05 Published:2017-06-05

摘要: 利用原位变温核磁共振氢谱(1H NMR)、核磁共振氟谱(19F NMR)和核磁共振磷谱(31P NMR)等NMR技术研究特定温度下离子液体的热分解机理.在温度低至80℃时,1-丁基-3-甲基咪唑阳离子(C4mim+)和六氟磷酸根阴离子(PF5—)组成的离子液体[C4mim][PF5]呈现1个缓慢但明显的分解过程.无水[C4mim][PF5]在温度高于80℃时开始分解,生成少量的五氟化磷(PF5)和氟化氢(HF),氟化氢中的氢原子来自于1-丁基-3-甲基咪唑环2位上的氢原子.在丢掉这个氢原子后,阳离子成环形成一个卡宾,并与PF5形成卡宾/PF5复合物.定量NMR分析显示在分解反应达到平衡状态时,自由态PF5和卡宾/PF5复合物的比例为7∶3.

关键词: 离子液体, 原位变温多核核磁共振, 热分解机理

Abstract: In situ variable-temperature 1H, 19F and 31P NMR spectroscopy was employed to study the thermal decomposition mechanisms of ionic liquid. At a temperature as low as 80℃, ionic liquid[C4mim] [PF5], composed of 1-butyl-3-methylimidazolium cation (C4mim+) and hexafluorophosphate anion (PF5-), had a slow, but detectable decomposition. For dehydrated[C4mim] [PF5], the ionic liquid started to decompose at temperature higher than 80℃. Small amount of PF5 and HF formed first. The proton in HF came from the proton at 2-position of 1-butyl-3-methylimidazolium cation ring. After losing the proton, a carbene structure was formed, which then formed complex with PF5. Free PF5 and PF5/carbene complex reached equilibrium at a ratio of 7:3.

Key words: in situ variable-temperature multi-nuclear NMR, ionic liquid, thermal decomposition mechanism

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