Molecular dynamics and a spectroscopic study of sulfur dioxide absorption by an ionic liquid and its mixtures with PEO

Molecular dynamics and a spectroscopic study of sulfur dioxide absorption by an ionic liquid and its mixtures with PEO

Author Hoher, Karina Autor UNIFESP Google Scholar
Cardoso, Piercarlo Fortunato Autor UNIFESP Google Scholar
Lepre, Luiz F Google Scholar
Ando, Romulo A. Google Scholar
Siqueira, Leonardo José Amaral Autor UNIFESP Google Scholar
Abstract An investigation comprising experimental techniques (absorption capacity of SO2 and vibrational spectroscopy) and molecular simulations (thermodynamics, structure, and dynamics) has been performed for the polymer poly(ethylene oxide) (PEO), the ionic liquid butyltrimethylammonium bis(trifluoromethylsulfonyl) imide ([N-4111][Tf2N]) and their mixtures as sulfur dioxide (SO2) absorbing materials. The polymer PEO has higher capacity to absorb SO2 than the neat ionic liquid, whereas the mixtures presented intermediary absorption capacities. The band assigned to the symmetric stretching band of SO2 at ca. 1140 cm(-1), which is considered a spectroscopic probe for the strength of SO2 interactions with its neighborhood, shifts to lower wavenumbers as more negative total interaction energy values of SO2 were evaluated from the simulations. The solvation free energy of SO2, DGsol, correlates linearly with the absorption capacity of SO2. The negative values of DGsol are due to negative and positive values of enthalpy and entropy, respectively. In the ionic liquid, SO2 weakens the cationanion interactions, whereas in the mixture with a high content of PEO these interactions are slightly increased. Such effects were correlated with the relative population of cisoid and transoid conformers of Tf2N anions as revealed by Raman spectroscopy. Moreover, the presence of SO2 in the systems provokes the increase of diffusion coefficients of the absorbing species in comparison with the systems without the gas. Proper to the slow dynamics of the polymer, the diffusion coefficient of ions and SO2 diminishes with the increase of the PEO content.
xmlui.dri2xhtml.METS-1.0.item-coverage Cambridge
Language English
Sponsor Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Grant number FAPESP: 2013/23234-7
FAPESP: 2011/22263-8
FAPESP: 2012/13119-3
Date 2016
Published in Physical Chemistry Chemical Physics. Cambridge, v. 18, n. 41, p. 28901-28910, 2016.
ISSN 1463-9076 (Sherpa/Romeo, impact factor)
Publisher Royal Soc Chemistry
Extent 28901-28910
Access rights Closed access
Type Article
Web of Science ID WOS:000386668200050

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