Dependence of the thermodynamic characteristics of the complexation of alanine-18-crown-6 on the composition of water-ethanol solvent

作者：Usacheva T R^*; Sharnin V A; Chernov I V

来源：Russian Journal of Physical Chemistry, 2013, 87(2): 204-207.

DOI：10.1134/S0036024413020313

• D,L-alanine
• binary solvents
• ethanol
• complexation
• stability constant
• solvation
• enthalpy
• Gibbs energy
• 18-crown-6 ether

Standard thermodynamic parameters (Delta(r) Gau <, Delta(r) Hau <, T Delta(r) Sau <) for the complexation reaction of 18-crown-6 ether (18C6) with D,L-alanine (Ala) in mixed water-ethanol (H2O-EtOH) solvents are calculated from the data of calorimetric titrations performed at T = 298.15 K. It is established that an increase in the concentration of EtOH in mixed solvent leads to a rise in stability and an increase in the exothermicity of [Ala18C6] molecular complex formation; changes in the energetics of reaction upon a change in the solvent composition are determined by changes in the solvation state of 18C6, which is typical of the reactions of molecular complex formation of 18C6 with D,L-alanine and glycine in water-organic solvents.

• 出版日期2013-2