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|Title: ||Liquid Mixtures Involving Hydrogenated and Fluorinated Alcohols: Thermodynamics, Spectroscopy, and Simulation|
|Authors: ||Morgado, Pedro|
Garcia, Ana Rosa
Ilharco, Laura M.
Martins, Luís F. G.
Filipe, Eduardo J. M.
|Keywords: ||Fluorinated alcohols|
|Issue Date: ||30-Aug-2016|
|Publisher: ||American Chemical Society|
|Citation: ||Pedro Morgado, Ana Rosa Garcia, Laura M. Ilharco, João Marcos, Martim Anastácio,
Luís F. G. Martins, Eduardo J. M. Filipe, Liquid Mixtures Involving Hydrogenated and Fluorinated Alcohols:
Thermodynamics, Spectroscopy, and Simulation, J. Phys. Chem. B 2016, 120, 10091−10105|
|Abstract: ||This article reports a combined thermodynamic, spectroscopic, and
computational study on the interactions and structure of binary mixtures of hydrogenated
and fluorinated substances that simultaneously interact through strong hydrogen bonding.
Four binary mixtures of hydrogenated and fluorinated alcohols have been studied, namely,
(ethanol + 2,2,2-trifluoroethanol (TFE)), (ethanol + 2,2,3,3,4,4,4-heptafluoro-1-butanol),
(1-butanol (BuOH) + TFE), and (BuOH + 2,2,3,3,4,4,4-heptafluoro-1-butanol). Excess
molar volumes and vibrational spectra of all four binary mixtures have been measured as a
function of composition at 298 K, and molecular dynamics simulations have been
performed. The systems display a complex behavior when compared with mixtures of
hydrogenated alcohols and mixtures of alkanes and perfluoroalkanes. The combined
analysis of the results from different approaches indicates that this results from a balance
between preferential hydrogen bonding between the hydrogenated and fluorinated
alcohols and the unfavorable dispersion forces between the hydrogenated and fluorinated
chains. As the chain length increases, the contribution of dispersion increases and
overcomes the contribution of H-bonds. In terms of the liquid structure, the simulations suggest the possibility of segregation
between the hydrogenated and fluorinated segments, a hypothesis corroborated by the spectroscopic results. Furthermore, a
quantitative analysis of the infrared spectra reveals that the presence of fluorinated groups induces conformational changes in the
hydrogenated chains from the usually preferred all-trans to more globular arrangements involving gauche conformations.
Conformational rearrangements at the CCOH dihedral angle upon mixing are also disclosed by the spectra.|
|Appears in Collections:||CQE - Publicações - Artigos em Revistas Internacionais Com Arbitragem Científica|
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