8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P2.2Tue 611:23-14:00Water + tert-butanol mixtures: ultrasonics, hypersonicsand molecular dynamicsAugustinus Asenbaum, 1 Christian Pruner, 1 Emmerich Wilhelm, 1 and AurelienPerera 21 University of Salzburg, Hellbrunnerstr. 34, A-5020, Salzburg, Austria2 Université Pierre et Marie Curie, Paris, FranceMixtures of alcohols with water have been studied extensively [1], the focus being on elucidatingthe impact of nonpolar groups on thermodynamic, transport and structural properties of suchsystems, and to thereby improve our knowledge on hydrophobic/hydrophilic effects. tert-Butyl alcohol(2-methyl-2-propanol), tert-C 4 H 9 OH, is of particular interest since, despite possessing threehydrophobic methyl groups attached to the tertiary carbon, it is completely miscible with water.Brillouin scattering studies on x 1 H 2 O + x 2 tert-C 4 H 9 OH were already reported by Oda et al. [2]and Asenbaum [3]. Renewed interest in this type of mixtures [4-9] prompted us to reinvestigatethis system at 298.15 K, over the entire composition range 0 ≤ x 2 ≤ 1. The most important resultsare found around the mole fractionx 2 = 0.1, where the sound absorption [10] shows a maximum which, at 298.15 K, is about 100times larger than the sound absorption of the pure substances, and the excess molar heat capacityat constant pressure amounts to about 16 J·K −1·mol −1 [11]. From our experiments, we determinedthe hypersonic speed (at ca. 5 GHz) and hence the sound dispersion over the whole compositionrange, as well as the nonrelaxing bulk viscosity (from the halfwidth of the Brillouin peaks). Thesedata are complemented by computer simulations. References [1] Water: A Comprehensive Treatise,Vol. 2, F. Franks, ed. , Plenum, New York, 1974. [2] K. Oda. R. Hayakawada, Jpn. J. Appl.Phys. 14, 1113 (1975). [3] A. Asenbaum, Z. Naturforsch. 31A, 201 (1976). [4] P. G. Kusalik,A. P. Lyubartsev, D. L. Bergman, A. Laaksonen, J. Phys. Chem. B 104, 9533 (2000). [5] D. T.Bowron, S. Diaz Moreno, J. Chem. Phys. 117, 3753 (2002). [6] T. Fukasawa, Y. Amo, Y. Tominaga,J. Chem. Phys. 118, 6387 (2003). [7] R. S. Cataliotti, F. Palombo, M. Paolantini, P. Sassi,A. Raudino, J. Chem. Phys. 126, 044505 (2007). [8] K. R. Harris, L. A. Woolf, J. Chem. Eng.Data 54, 581 (2009). [9] H. Al Rasid Gazi, R. Biswas, J. Phys. Chem. A 115, 2447 (2011). [10]C. J. Burton, J. Acoust. Soc. Am. 20, 186 (1948). [11] C. de Visser, G. Perron, J. E. Desnoyers,Can. J. Chem. 55, 856 (1977).2