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Structure and dynamics of aqueous 2-propanol: a THz-TDS, NMR and neutron diffraction study.
- Source :
-
Physical chemistry chemical physics : PCCP [Phys Chem Chem Phys] 2015 Nov 11; Vol. 17 (45), pp. 30481-91. - Publication Year :
- 2015
-
Abstract
- Aqueous liquid mixtures, in particular, those involving amphiphilic species, play an important role in many physical, chemical and biological processes. Of particular interest are alcohol/water mixtures; however, the structural dynamics of such systems are still not fully understood. Herein, a combination of terahertz time-domain spectroscopy (THz-TDS) and NMR relaxation time analysis has been applied to investigate 2-propanol/water mixtures across the entire composition range; while neutron diffraction studies have been carried out at two specific concentrations. Excellent agreement is seen between the techniques with a maximum in both the relative absorption coefficient and the activation energy to molecular motion occurring at ∼90 mol% H2O. Furthermore, this is the same value at which well-established excess thermodynamic functions exhibit a maximum/minimum. Additionally, both neutron diffraction and THz-TDS have been used to provide estimates of the size of the hydration shell around 2-propanol in solution. Both methods determine that between 4 and 5 H2O molecules per 2-propanol are found in the 2-propanol/water clusters at 90 mol% H2O. Based on the acquired data, a description of the structure of 2-propanol/water across the composition range is presented.
Details
- Language :
- English
- ISSN :
- 1463-9084
- Volume :
- 17
- Issue :
- 45
- Database :
- MEDLINE
- Journal :
- Physical chemistry chemical physics : PCCP
- Publication Type :
- Academic Journal
- Accession number :
- 26513021
- Full Text :
- https://doi.org/10.1039/c5cp01132a