The Use of Calorimetry to Study Reaction Kinetics

In this study reaction calorimetry was used to determine information about the rates of chemical reactions. The rate of reaction heat evolution is proportional to the rate of reaction and the quantities of the reacting species may be calculated from the heat evolved by a reacting system. This means that data for both the rate of reaction and the concentrations of the reacting species are available from one experiment. This information was used to determine the most likely kinetic model and to solve the rate equation giving the reaction rate constants.
Complications arose when more than one reaction occurred in the system resulting in more than one exotherm contributing to the observed heat evolution. The resultant mathematical complexities were far easier to resolve when a differential method of kinetic analysis was used.
The calorimeter used in this work measures the rate of reaction heat output. This was found to be directly compatible with the selected method of data analysis. The calorimeter system also recorded other important reaction mixture parameters, this permitted direct investigation of semi-batch reactions.
Unlike many reaction kinetic studies, the experimental procedure used in this work incorporated reactions at industrial concentrations using commercial grade reagents. This provided access to systems of true industrial importance, operating under the conditions used in large scale chemical processes.
Data generated by computer simulation which was free of normal calorimetry errors was used to demonstrate the principle of the method. It was then possible to modify the simulation data to include the commonly encountered systematic errors for reaction calorimetry data which showed the effect of these errors on the reaction kinetic results. These modified data were also used to demonstrate that the method of data analysis was more resistant to these errors than other possible methods