Enthalpies of dilution of l-cystine in aqueous solutions of sodium hydroxide, potassium hydroxide and hydrochloric acid

The enthalpies of dilution of l-cystine in solutions of two strong alkalis and one strong acid have been determined by isothermal flow-mix calorimetry at the temperatures 298.15 K, 303.15 K, 308.15 K, 313.15 K and 318.15 K. Equations of apparent enthalpies of dilution have been obtained from the experimental data in terms of the improved McMillan–Mayer theory. Enthalpic interaction coefficients, h 2, h 3, and h 4, are obtained and the values of pair-wise enthalpic interaction coefficient, h 2, discussed in the light of solute–solute and solute–solvent interactions.