Theoretical evaluation and limitations of the extrapolation method for measuring reaction enthalpy by titration calorimetry

The extrapolation method of evaluating reaction enthalpies in thermometric titrations is examined by computing theoretical curves from the fundamental equations and simulating the extrapolation by means of a least-square best fit to the temperature-time curve. The accuracy of the method is dependent upon the magnitude of the heat transfer modulus of the calorimeter, the rate of change of heat capacity due to titrant addition, and the details of the extrapolation procedure. Computed results show that the complex equations can be accurately simulated by a simple algorithm. Use of this mathematical device leads to an accurate (0.1-0.5%) method of data evaluation which does not require measurement of the heat transfer characteristics of the calorimeter.