Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

The interactions of amino acids glycine, L-alanine and L-valine with tetraethylammonium iodide (TEAI) as a function of temperature have been investigated by a combination of volumetric and acoustic measurement. Densities oqP and ultrasonic speeds ouP of amino acids in aqueous solutions of TEAI have been measured at T = (288.15, 293.15, 298.15, 303.15 and 308.15) K and p = 0.1 MPa. The apparent molar volume oV;P, the partial molar volume and standard partial molar volumes of transfer for amino acids from water to aqueous TEAI solutions have been calculated from density values. Apparent molar isentropic compressibility, partial molar isentropic compressibility, partial molar isentropic compressibility of transfer have been calculated from values of the ultrasonic speed. The pair and triplet interaction coefficients have been calculated from both properties. The linear variation of V0 with the number of carbon atoms in the alkyl chain of amino acids has been utilized to calculate the contribution of the charged end groups (NH3+,COO-), (CH2) group and other alkyl chains of the amino acids to V0. The results obtained are discussed in the light of various interactions operating in ternary systems of amino acids, water and TEAI.