Alkaline Stability of Quaternary Ammonium Cations for Alkaline Fuel Cell Membranes and Ionic Liquids
Alkaline Stability of Quaternary Ammonium Cations for Alkaline Fuel Cell Membranes and Ionic Liquids
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DOI：
10.1002/cssc.201403022
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发表时间：
2015-02-01
期刊：
影响因子：
8.4
通讯作者：
Kreuer, K. D.
中科院分区：
文献类型：
--
作者：
Marino, M. G.;Kreuer, K. D.
研究了26种不同季铵盐基(QA)在温度高达160℃、NaOH浓度高达10molL(-1)条件下的碱性稳定性，旨在为碱性燃料电池氢氧化物交换膜官能团的选择和碱性条件下稳定的离子-液体阳离子提供依据。除了芳香族阳离子外，大多数QA都表现出出人意料的高碱性稳定性。-质子被发现比以前建议的更不容易受到亲核攻击，而苄基、附近的杂原子或其他吸电子物种的存在显著促进了降解反应。环QAS被证明是非常稳定的，在所选择的条件下，基于哌啶的6-氮杂螺[5.5]十一烷具有最高的半衰期。本文提出的绝对和相对稳定性与文献数据相反，差异归因于溶剂对降解的影响。
The alkaline stability of 26 different quaternary ammonium groups (QA) is investigated for temperatures up to 160 degrees C and NaOH concentrations up to 10molL(-1) with the aim to provide a basis for the selection of functional groups for hydroxide exchange membranes in alkaline fuel cells and of ionic-liquid cations stable in basic conditions. Most QAs exhibit unexpectedly high alkaline stability with the exception of aromatic cations. -Protons are found to be far less susceptible to nucleophilic attack than previously suggested, whereas the presence of benzyl groups, nearby hetero-atoms, or other electron-withdrawing species promote degradation reactions significantly. Cyclic QAs proved to be exceptionally stable, with the piperidine-based 6-azonia-spiro[5.5]undecane featuring the highest half-life at the chosen conditions. Absolute and relative stabilities presented herein stand in contrast to literature data, the differences being ascribed to solvent effects on degradation.