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I. N. Mezhevoy, V. G. Badelin

Author affiliations
Institute of Solution Chemistry RAS Laboratory “thermodynamics of non-electrolyte solutions and active substances”
153045 Ivanovo, Akademicheskaya Str., 1. 
E-mail: inm@isc-ras.ru

Abstract
Integrated enthalpies of dissolution Δ_solН^m L-cysteine and L-asparagine in mixes of water with acetonitrile, dioxane, dimethyl sulfoxide and acetone at concentration of alcohol up to 0,32 м.д. are measured by the method of dissolution calorimetry. Standard values of dissolution enthalpies (Δ_solН⁰) and transfer (Δ_trН⁰) of amino acids from water in the mixed solvent are designed. It is established, that dependences of Δ_solН⁰ and Δ_trН⁰ on structure of water-organic solutions have extreme character. The designed enthalpic coefficients of pair interactions of amino acids with molecules of cosolvent have positive values, except for L-asparagine-acetonitrile system. The data received are interpreted from the point of view of various types of interactions in solutions and influences of the nature of amino acid fragments on thermochemical characteristics of dissolution.

Keywords: amino acids, calorimetry, solutions, aqueous-organic solutions