Simulation of calorimetric titration of complexation system

A general mathematical model of calorimetric titration curves for metal-ligand complexation systems has been developed. The model can be applied to more complicated complexation systems such as those forming more than two complexes with the use of auxiliary complexing agents or buffer to prevent the precipitation of metal ion as hydroxides or basic salts. The model can be used to predict the shape of calorimetric titration curves of different complexation systems and to explore the optimum conditions of calorimetric titration experiments, such as the region of pH, the concentrations of auxiliary complexing agent, metal ion solution, and ligand solution prior to the experiment. Combined with the improved parameter optimization approach developed in this work, the model can be used to determine simultaneously log$rm betasb{i} (Delta Gsb{i}), Delta Hsb{dotnu},$ and $Deltarm Ssb{i}$ values of a complexation system forming up to six complexes from one single calorimetric titration. The method can also be used to identify or confirm the reaction type or mechanism of a complexation system. It can provide a complete set of thermodynamic parameters of a complexation system being studied more conveniently, accurately and quickly. In extraction and separation chemistry, it also can be used as a technique to quickly screen different complexing agents and set up optimum experimental conditions for efficient separation of metal ions. This method has been tested with simulated metal-ligand complexation systems with known values of log$betarm sb{i}$ and a $rm Delta Hsb{i}.$.