Thermodynamic Functions in the Binary System of a C60 Fullerene Derivative with Methionine Amino Acid–Н2О
Abstract
The temperature of the onset of ice crystallization (∆Т) is determined for binary aqueous solutions of a water-soluble tris-adduct of light fullerene with methionine С60(C5H11NO2S)3 in the temperature range of 272.58–273.15 K. It is found that the bis-adduct concentration varies over a wide range of the mole fraction scale: x = 0.000–7.71 × 10−5 arb. units. Liquidus temperatures are measured using a Beckmann thermometer with a linear scale resolution of ∆T/∆h ≈ 0.01 K/mm. Partial molar excess functions are calculated for H2O. An original semi-empirical VD-AS model is developed to provide a thermodynamic description of such systems. This model is based on a virial expansion of the molar Gibbs energy in terms of mole fractions of components in the solution. Partial molar functions of the bis-adduct are calculated using the VD-AS model. The excess and average total molar Gibbs energies of solutions and gaps in concentration miscibility are calculated. It is concluded that the VD-AS model accurately describes the processes of pre-lamination or microheterogeneous structure formation.