Université François Rabelais, Laboratoire PCMB (EA 4244), équipe de Chimie-physique des Interfaces et des Milieux Electrolytiques (CIME), Parc de Grandmont 37200 Tours, France.
J Phys Chem B. 2010 Feb 11;114(5):1757-66. doi: 10.1021/jp906917v.
New protic ionic liquids (PILs) based on the morpholinium, N-methylmorpholinium, and N-ethyl morpholinium cations have been synthesized through a simple and atom-economic neutralization reaction between N-alkyl morpholine and formic acid. Their densities, refractive indices, thermal properties, and electrochemical windows have been measured. The temperature dependence of their dynamic viscosity and ionic conductivity have also been determined. The results allow us to classify them according to a classical Walden diagram and to evaluate their "fragility". In addition, morpholinium based PILs exhibit a large electrochemical window as compared to other protic ionic liquids (up 2.91 V) and possess relatively high ionic conductivities of 10-16.8 mS x cm(-1) at 25 degrees C and 21-29 mS x cm(-1) at 100 degrees C, and a residual conductivity close to 1.0 mS x cm(-1) at -15 degrees C. PIL-water mixtures exhibit high ionic conductivities up to 65 mS x cm(-1) at 25 degrees C and 120 mS x cm(-1) at 100 degrees C for morpholinium formate with water weight fraction w(w) = 0.6. Morpholinium based PILs studied in this work have a low cost and low toxicity, are good ionic liquids, and prove extremely fragile. They have wide applicable perspectives as electrolytes for fuel cell devices, thermal transfer fluids, and acid-catalyzed reaction media as replacements of conventional solvents.
已通过 N-烷基吗啉与甲酸之间的简单且原子经济性的中和反应，合成了基于吗啉鎓、N-甲基吗啉鎓和 N-乙基吗啉鎓阳离子的新型质子离子液体（PILs）。测量了它们的密度、折射率、热性能和电化学窗口。还测定了它们动态粘度和离子电导率随温度的变化。结果允许我们根据经典的 Walden 图对它们进行分类，并评估它们的“脆弱性”。此外，与其他质子离子液体相比，基于吗啉鎓的 PIL 具有较大的电化学窗口（高达 2.91 V），并且在 25°C 时具有相对较高的离子电导率 10-16.8 mS x cm(-1)，在 100°C 时具有 21-29 mS x cm(-1)，在-15°C 时残导接近 1.0 mS x cm(-1)。PIL-水混合物在 25°C 时表现出高达 65 mS x cm(-1)的高离子电导率，在 100°C 时高达 120 mS x cm(-1)，对于水重量分数 w(w) = 0.6 的吗啉甲酸。在这项工作中研究的基于吗啉鎓的 PIL 具有低成本、低毒性、良好的离子液体特性，并且非常脆弱。它们作为燃料电池设备、热传递流体和酸催化反应介质的电解质具有广阔的应用前景，可替代常规溶剂。
