Thermochemical investigation of interaction of L-serin with glycerol, ethylene glycol, and 1,2-propylene glycol in aqueous solutions

By the method of dissolution calorimetry integral enthalpies of dissolution Delta(sol) H (m) of L-serine are measured in the mixtures of water with glycerol, ethylene glycol, and 1,2-propylene glycol at the concentration of the organic solvent up to 0.42 mole fraction. The standard values of enthalpies of dissolution (Delta(sol) H (0)) and transfer (Delta(tr) H (0)) of amino acids from water to mixed solvents are calculated. The calculated values of the enthalpy coefficients of pair interactions of L-serine with the molecules of co-solvents are positive. The data obtained are interpreted in terms of prevalence of different types of interactions in solutions and the influence of nature of co-solvents on the thermochemical characteristics of the dissolved amino acids.