We compare the effects of water, either intentionally added or due to absorption from the air, on the phase diagram of the hydrophilic 1-butyl-3-methylimidazolium dicyanamide ionic liquid, extending previous investigations to lower temperatures (down to 140 K), with a special attention to the changes of the environment of water molecules and the interface between water and ionic liquid as a function of temperature. Experiments: Combined infrared spectroscopy and ab-initio calculations provide information about the phase transitions and the intermolecular changes occurring in the liquid. Findings: The temperature dependence of the mid-infrared spectrum in the temperature range between 140 and 330 K indicates that in both cases the liquid undergoes a glass transition, but, when the water content is only due to absorption from air, a cold crystallization takes place on heating between 240 and 265 K, while it is suppressed when water is intentionally added in a greater amount. The analysis of the OAH stretching bands indicates the existence of two different ‘‘liquid like” water environments. When cold crystallization takes places the water molecules, which seem less coordinated to the other H2O molecules and more related to the anions, appear to be part of the crystallized sample. In both cases, it seems that at microscopic level the sample is not homogeneous, but more likely it is composed of separated clusters or regions of bulk water confined in the ionic liquid.

Crystallization of mixtures of hydrophilic ionic liquids and water: Evidence of microscopic inhomogeneities / Palumbo, O.; Trequattrini, F.; Brubach, J. -B.; Roy, P.; Paolone, A.. - In: JOURNAL OF COLLOID AND INTERFACE SCIENCE. - ISSN 0021-9797. - 552:(2019), pp. 43-50. [10.1016/j.jcis.2019.05.034]

Crystallization of mixtures of hydrophilic ionic liquids and water: Evidence of microscopic inhomogeneities

Trequattrini, F.;
2019

Abstract

We compare the effects of water, either intentionally added or due to absorption from the air, on the phase diagram of the hydrophilic 1-butyl-3-methylimidazolium dicyanamide ionic liquid, extending previous investigations to lower temperatures (down to 140 K), with a special attention to the changes of the environment of water molecules and the interface between water and ionic liquid as a function of temperature. Experiments: Combined infrared spectroscopy and ab-initio calculations provide information about the phase transitions and the intermolecular changes occurring in the liquid. Findings: The temperature dependence of the mid-infrared spectrum in the temperature range between 140 and 330 K indicates that in both cases the liquid undergoes a glass transition, but, when the water content is only due to absorption from air, a cold crystallization takes place on heating between 240 and 265 K, while it is suppressed when water is intentionally added in a greater amount. The analysis of the OAH stretching bands indicates the existence of two different ‘‘liquid like” water environments. When cold crystallization takes places the water molecules, which seem less coordinated to the other H2O molecules and more related to the anions, appear to be part of the crystallized sample. In both cases, it seems that at microscopic level the sample is not homogeneous, but more likely it is composed of separated clusters or regions of bulk water confined in the ionic liquid.
2019
Ionic liquids; Infrared spectroscopy; Water Interactions
01 Pubblicazione su rivista::01a Articolo in rivista
Crystallization of mixtures of hydrophilic ionic liquids and water: Evidence of microscopic inhomogeneities / Palumbo, O.; Trequattrini, F.; Brubach, J. -B.; Roy, P.; Paolone, A.. - In: JOURNAL OF COLLOID AND INTERFACE SCIENCE. - ISSN 0021-9797. - 552:(2019), pp. 43-50. [10.1016/j.jcis.2019.05.034]
File allegati a questo prodotto
File Dimensione Formato  
Palumbo_Crystallization_2019.pdf

solo gestori archivio

Tipologia: Versione editoriale (versione pubblicata con il layout dell'editore)
Licenza: Tutti i diritti riservati (All rights reserved)
Dimensione 1.35 MB
Formato Adobe PDF
1.35 MB Adobe PDF   Contatta l'autore

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1268386
Citazioni
  • ???jsp.display-item.citation.pmc??? 1
  • Scopus 8
  • ???jsp.display-item.citation.isi??? 8
social impact