Thermochemical Characteristics of Interactions of DL-Alanine in Aqueous Solutions of Glycerol, Ethylene Glycol, and 1,2-Propylene Glycol

摘要

The method of dissolution calorimetry was used to measure the integral enthalpy of dissolution Δ_(sol)H~(m) of DL -alanine in mixtures of water with glycerol, ethylene glycol, and 1,2-propylene glycol at a concentration of organic solvent up to 0.32 mole fraction. The standard dissolution enthalpy (Δ_(sol)H~(0)) and transport enthalpy of amino acids from water to mixed solvent (Δ_(tr)H~0) were calculated. The calculated enthalpy coefficients of pair interactions of the DL-alanine molecules with the polyol molecules are positive and less than these values for L-alanine. The effect of interactions of different types in solution and the structural features of biomolecules and co-solvents on the enthalpy of dissolution characteristics of amino acids were considered.