Unraveling the Stepwise Melting of an Ionic Liquid

Author(s)

Lima, Thamires A. ; Paschoal, Vitor H. ; Faria, Luiz F. O. ; Ribeiro, Mauro C. C.

• Document type: Journal article
• Source: Journal of Physical Chemistry B; v. 121, n. 17, p. 4650-4655, MAY 4 2017.
• Web of Science Citations: 4

Abstract

Differential scanning calorimetry, X-ray diffraction, and Raman spectros-copy were used to reveal the premelting events precursors of melting of the ionic liquid triethylsulfonium bis(trifluoromethanesufonyl)imide, {[}S-222]{[}NTf2]. On heating the crystalline phase of {[}5222]{[}NTf2], melting occurs along a sequence of at least three steps. First, the crystalline long-range order breaks down, but local order is retained. The second step is characterized by conformational freedom of the ethyl chains of cations related to premelting of nonpolar domains, and the complete melting finally occurs when anions acquire conformational freedom. This work provides a microscopic view on the mechanism of melting of {[}S-222] {[}NTf2] in line with the picture of melting taking place as a sequence of structural changes. The results of this work shed light on the understanding of the complex melting process of ionic liquids. (AU)

• FAPESP's process: 15/05803-0 - Ionic liquid structure under high pressure
• Grantee: Luiz Felipe de Oliveira Faria
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 15/07516-8 - Collective dynamics of ionic liquids
• Grantee: Vitor Hugo Paschoal
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 12/13119-3 - Vibrational spectroscopy in condensed phases
• Grantee: Mauro Carlos Costa Ribeiro
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 14/15049-8 - A Raman spectroscopy study of the glass transition of ionic liquids under high pressure.
• Grantee: Thamires Andrade Lima
• Support Opportunities: Scholarships in Brazil - Post-Doctoral