Enthalpy characteristics of dissolution of L-tryptophan in water + formamides binary solvents at 298.15 K
Abstract
Enthalpies of dissolution of L-tryptophan in aqueous solutions of formamide (FA), N-methylformamide (MFA), and N, N-dimethylformamide (DMF) are measured according to calorimetry at the concentration of amides x 2 = 0-0.4 mole fraction. Standard values of enthalpies of dissolution and transfer Δtr H o of L-tryptophan from water to binary solvent, as well as enthalpy coefficients of pair-wise interactions h xy of L-tryptophan with formamide molecules are calculated. The effect the composition of a waterorganic mixture has on the enthalpy characteristics of L-tryptophan is considered. The relation of Δtr H o of L-tryptophan with the structure of amides is shown. A quantitative estimation of the contributions to the energy of L-tryptophan-formamide pair-wise interactions determined by polarity/polarizability, acidity, and basicity of organic solvent is performed using the four-parameter Kamlet-Taft correlation equation.
- Publication:
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Russian Journal of Physical Chemistry A
- Pub Date:
- July 2013
- DOI:
- 10.1134/S0036024413070285
- Bibcode:
- 2013RJPCA..87.1165S
- Keywords:
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- amino acids;
- enthalpies of dissolution and transfer;
- water-organic mixtures