Practical Estimation Techniques for Determination of Reaction Heat

Heat of reaction estimation is often necessary to calculate the adiabatic temperature rise and maximum temperature of a chemical reaction (synthesis, quench, etc.) in order to understand the worst-case scenario for thermal hazard evaluation. This paper details best practices, utilizing various techniques, to estimate heats of reaction at Corteva Agriscience, where hundreds of such estimations are done annually. The recommended thermochemistry data sources offer over 25 000 reliable heat of formation data; however, many reactions need to be simplified to a "model reaction" in order to estimate the heat of reaction. An analogue approach used to find a "model reaction" is presented. In addition, various simple prediction methods for phase transition enthalpies as well as heat capacity are evaluated by comparing prediction results with a large pool of literature data to increase the accuracy of heat of reaction estimation. The uncertainty of heat of reaction results is evaluated on the basis of assigned uncertainties for each data source. Finally, a decision tree used at Corteva to determine which techniques should be used for heat of reaction estimation is shared.