Abstract
Equations describing the temperature jump amplitudes associated with a system of two coupled reactions (TRIS-phenol red) as well as the ternary system (Mg2+-iminodiacetic acid-phenol red) are presented. The termodynamic parameters calculated from experimentally measured temperature perturbation amplitudes using a multiparametric curve fitting procedure are found to be in good agreement with those determined from pH- and costant rate thermometric titrations. For phenol red, pK I =7.55, ΔH I =3.45 kcal, and for Mg2+ iminodiacetic acid, log K M =2.84, ΔH M =3.25 kcal, were obtained. It is shown that this method can be used to determine accurate thermodynamic enthalpy changes over a narrow temperature interval of less than 1.0°C from a single experiment requiring about 50 μl of sample solution.
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Ushio, H., Trimm, H.H., Patel, R.C. et al. Thermodynamic parameters of coupled chemical reactions from temperature jump relaxation amplitudes. J Solution Chem 10, 39–50 (1981). https://doi.org/10.1007/BF00652779
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DOI: https://doi.org/10.1007/BF00652779