Abstract
New experimental data at 25°C for the density, velocity of sound, refractive index, and viscosity of aqueous solutions of DL-alanine and NaCl are reported. The apparent molar volume and isentropic compressibility of DL-alanine in aqueous electrolyte solutions have been calculated from the measured properties. The results show that DL-alanine exhibits a positive volume transfer to solutions of a higher NaCl concentration and a negative apparent isentropic compressibility for DL-alanine in the presence of NaCl. These effects indicate that the apparent volume of DL-alanine is larger in solutions with higher electrolyte concentration and the water molecules surrounding the DL-alanine molecules are less compressible than the water molecules in the bulk solution. The results also show an increase in the viscosity of the solution with an increase in both DL-alanine and NaCl concentrations. These effects are attributed to the two charged groups of DL-alanine and the interactions between the charged groups and the hydrocarbon backbone of DL-alanine with the ions. A model, consisting of a short-range interaction term represented by a virial expansion and a Debye-Hückel term that considers long-range interactions, has been developed to correlate the measured experimental data.
Similar content being viewed by others
References
M. Mizuguchi, M. Sakurai, and K. Nitta, J. Chem. Eng. Data 40, 935(1995).
M. Mizuguchi, M. Sakurai, and K. Nitta, J. Solution Chem. 26, 579(1997).
M. Iqbal and R. E. Verrall, J. Phys. Chem. 91, 967(1987).
R. Bhat and J. C. Ahluwalia, J. Phys. Chem. 89, 1099(1985).
T. V. Chalikian, V. S. Gindikin, and K. J. Breslauer, Biophys. Chem. 75, 57(1998).
G. R. Hedwig, and H. Høiland, J. Solution Chem. 20, 1113(1991).
M. Natarajan, R. K. Wadi, and H. C. Gaur, J. Chem. Eng. Data 35, 87(1990).
A. Soto, A. Arce, and M. K. Khoshkbarchi, Biophysical Chem. 74 165(1998).
I. N. Basumallick, R. K. Mohanty, and U. Chakraborty, Indian J. Chem. 25A, 1089(1986).
T. Ogawa, K. Mizutani, and M. Yasuda, Bull. Chem. Soc. Jpn. 57, 2064(1984).
J. A. Riddick, W. B. Bunger, and T. Sakano, in Organic Solvents, 4th edn. (John Wiley, New York, 1986).
M. K. Khoshkbarchi and J. H. Vera, Ind. Eng. Chem. Res. 35, 2735(1996).
M. J. C. Esteves, M. J. E. de M. Caradoso, and O. E. Barica, Ind. Eng. Chem. Res. 40, 5021(2001).
D. Feakins, W. E. Waghorne, and K. G. Lawrence, J. Chem. Soc. Faraday Trans. 1 82, 563(1986).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Rodríguez, H., Soto, A., Arce, A. et al. Apparent Molar Volume, Isentropic Compressibility, Refractive Index, and Viscosity of DL-Alanine in Aqueous NaCl Solutions. Journal of Solution Chemistry 32, 53–63 (2003). https://doi.org/10.1023/A:1022640715229
Issue Date:
DOI: https://doi.org/10.1023/A:1022640715229