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Thermal characterization of ethylammonium nitrate

Beyond their traditional usage in fuel cell applications, the category of protic ionic liquids (PILs) has been recently signalled as a potential candidate for battery applications [1]. Despite being the oldest known IL [2], and of having been extensively characterized in most of its properties [3], a full thermal and stability analysis of ethylammonium nitrate (EAN) both in its solid and liquid phases is still lacking. In the present work thermal analysis techniques were used to characterize its thermal transitions and thermal stability.

A differential scanning calorimeter DSC Q100 TA-Instruments with aluminium pans hermetically sealed was used to determine the different state transitions experienced by the IL during heating and cooling cycles [4]. Results showed that this IL is a very good crystal-former with melting and freezing peaks at 17ºC and -28ºC respectively. Moreover, stability analysis has been performed by means of a thermogravimetric analyser (TGA 7-Perkin Elmer) operating in dynamic and isothermal modes, under nitrogen and dry air atmospheres was used to perform thermal stability analysis [5]. Similar onset temperatures in air and nitrogen of 248±4ºC were obtained. Additionally, activation energy of the degradation process of this IL has been determined using the Arrhenius equation.


This work was funded by the Xunta de Galicia (Spain) through grants EM2013/031 and AGRUP2015/11 and by the network REGALIS R2014/015. The financial support of the Spanish Ministry of Economy and Competitiveness through grants MAT2014-57943-C3-1-P, MAT2014-57943-C3-2-P and MAT2014- 57943-C3-3-P is also gratefully acknowledged. Funding from the European Union (COST Action CM 1206) is also acknowledged.


[1] S. Menne, J. Pires, M. Anouti, A. Balducci, Electrochem. Commun. 31, 39 (2013).

[2] P. Walden, Chem. Zentralbl. 85: 1800 (1914).

[3] S. Bouzón Capelo, T. Méndez-Morales, J. Carrete, E. López Lago, J. Vila, O. Cabeza, J. R. Rodríguez, M. Turmine, and L. M. Varela, J. Phys. Chem. B, 116 ,11302 (2016).

[4] M. Villanueva, J. J. Parajó, P.B. Sánchez, J. García, J. Salgado, J. Chem. Thermodyn. 91, 127 (2015).

[5] J. Salgado, J. J. Parajó, J. Fernández, M. Villanueva, J. Chem. Thermodyn. 74, 51(2014).

Keywords: Ionic liquid, melting point, thermal stability, fuel cell