title: Peculiarity of aqueous solutions of 2,2,2-trifluoroethanol.
abstract: Aqueous solutions of 2,2,2-trifluoroethanol appear to show a structural transition at alcohol mole fraction equal to x(TFE) = 0.05, which can be concluded from a discontinuity of the speed of sound. At the same concentration, a discontinuity was observed in the parameters of the long-living component of the positron annihilation spectrum. Moreover, the partial molar volumes of components show transition-like behavior in the range of low solute contents, which is significantly different from nonsubstituted ethanol. The peculiarities of the low concentration system correlate with minor infrared spectra changes assigned to a mode composed of the CH(2) bending and CF(3) stretching internal vibrations being sensitive to polarity of the hydration shell surrounding the solute. The majority of the spectral changes arise from a gradual shift of the equilibrium between trans ↔ gauche isomers when the composition of the solution is changing. A possible explanation for the peculiar behavior of the system is a thermodynamic equilibrium between hydrated monomers and dimers at that respective mole number.
authors.affiliation: Faculty of Chemistry, University of Wrocław, Wrocław, Poland. andrzej.burakowski@gmail.com
authors.forename: Andrzej
authors.initials: A
authors.lastname: Burakowski
authors.forename: Jacek
authors.initials: J
authors.lastname: Gliński
authors.forename: Bogusława
authors.initials: B
authors.lastname: Czarnik-Matusewicz
authors.forename: Paulina
authors.initials: P
authors.lastname: Kwoka
authors.forename: Andrzej
authors.initials: A
authors.lastname: Baranowski
authors.forename: Kazimierz
authors.initials: K
authors.lastname: Jerie
authors.forename: Helge
authors.initials: H
authors.lastname: Pfeiffer
authors.forename: Nikos
authors.initials: N
authors.lastname: Chatziathanasiou
mesh_terms: D000431:Ethanol / Q000737:chemistry; D007536:Isomerism; D013055:Spectrophotometry, Infrared; D014270:Trifluoroethanol / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D000431:Ethanol; D014270:Trifluoroethanol