Enthalpies of Dilution of Colchicine in Aqueous NaCl Solutions

摘要

The concentration effect on the dilution enthalpies ( dilHm) of colchicine (COL) in aqueous NaCl solutions has been investigated by isothermal titration microcalorimetry at 298.15 K. The corresponding homogeneous enthalpic interaction coefficients have been calculated according to the excess enthalpy concept. The results show that the dilution enthalpies of COL in aqueous NaCl solutions at different mass fractions are positive. The overall trend is that enthalpies of dilution become more positive with the increase of the salt mass fraction. The values of enthalpic pair-wise interaction coefficients, h2, have been obtained by fitting the data of the enthalpies of dilution with a viral expansion. The results can be interpreted from the view of solute-solute and solute-solvent interactions involved in the solvent effects.