On the physical properties of mixtures of nitrate salts and protic ionic liquids
| Autor: | Pablo Vallet, Silvia Bouzón-Capelo, Trinidad Méndez-Morales, Víctor Gómez-González, Yago Arosa, Raúl de la Fuente, Elena López-Lago, Julio R. Rodríguez, Luis J. Gallego, Juan J. Parajó, Josefa Salgado, Mireille Turmine, Luisa Segade, Oscar Cabeza, Luis M. Varela |
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| Přispěvatelé: | Universidade de Santiago de Compostela. Departamento de Física Aplicada, Universidade de Santiago de Compostela. Departamento de Física de Partículas |
| Jazyk: | angličtina |
| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | Minerva. Repositorio Institucional de la Universidad de Santiago de Compostela instname RUC. Repositorio da Universidade da Coruña |
| Popis: | [Abstract] We report a systematic study of the effect of salt concentration and its cation valence on several equilibrium and transport properties of mixtures of the model protic ionic liquid ethylammonium nitrate with monovalent (LiNO3), divalent (Mg(NO3)2 and Ca(NO3)2), and trivalent (Al(NO3)3) salts. These properties, determined by appropriate experimental techniques, include density, sound velocity, refractive index, surface tension, conductivity and viscosity. Single-particle dynamics and radial distribution functions were also analyzed by means of molecular dynamics simulations. The temperature dependence of the conductivity was studied in the Vogel-Fulcher-Tammann framework, and we obtained effective activation energies, fragility indexes, and Vogel temperatures. In addition, we performed a high-temperature Arrhenius analysis and we calculated the activation energies of both conductivity and viscosity. Finally, the exponents of the fractional Walden rule for the different mixtures were obtained and the ionicities and fragilities of the systems were analyzed, proving that all the mixtures are subionic and fragile. The distortion of the network of hydrogen bonds characteristic of protic ionic liquids and the formation of long-lived anionic aggregates composed of the cations of the added salt and the nitrate anions in their first solvation shell were found to have a deep impact on the analyzed properties. The role of the surface charge density of the salt cations on the structure and transport properties of the solutions is detailedly analyzed and related to solvation of salt species in the polar nanoregions of the ionic liquid (nanostructured solvation). The financial support of the Spanish Ministry of Economy and Competitiveness (Projects MAT2017-89239-C2-1-P and MAT2017-89239- C2-2-P) is gratefully acknowledged. Moreover, this work was funded by the Xunta de Galicia (ED431D 2017/06, ED431E 2018/08, GRC ED431C 2016/001 and GRC ED431C 2020/10). All these research projects were partially supported by FEDER. P. V. thanks the Spanish Ministry of Science, Innovation and Universities for his FPI grant (PRE2018-084212). T.M.-M. thanks the Spanish Ministry of Science, Innovation and Universities for her Juan de la Cierva grant (IJC2018-036774-I).J. J. Parajó thanks the funding support of I2C postdoctoral program of Xunta de Galicia. Y. A. thanks the funding support from postdoctoral Program of Xunta de Galicia (ED481B-2021-027). Facilities provided by the Galician Supercomputing Centre (CESGA) are also acknowledged Xunta de Galicia; ED431D 2017/06 Xunta de Galicia; ED431E 2018/08 Xunta de Galicia; ED431C 2016/001 Xunta de Galicia; ED431C 2020/10 Xunta de Galicia; ED481B-2021-027 |
| Databáze: | OpenAIRE |
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