Vapor pressure, heat of vaporization, and liquid heat capacity are linked through fundamental thermodynamic relationships. These related properties are essential for the safe design of many industrial processes, and measurement and prediction of these properties remains an essential part of modern thermodynamics research. DIPPR uses the fundamental relationships connecting these properties as a prediction method for all three, referred to as "the derivative method." DIPPR regards values predicted using the derivative method as highly accurate, even when compared to more traditional predictions. Despite the widespread interest in improving understanding of these properties, many questions remain regarding their prediction. Foremost among these is the treatment of associating chemicals, defined here as any species with strong hydrogen bonding. Associating species have large intermolecular attraction that is hard to compensate for in traditional equation of state modeling. For this reason, using thermodynamic relationships to predict properties of associating species is often grossly inaccurate. Improving the prediction of thermodynamic properties for this group of chemicals has been a goal of thermodynamicists and engineers for over 70 years. In this work, we set out to solve the problem of association for prediction of these properties. We began with high-level quantum calculations to determine the extent of association in several family groups and tested these against experimental measurements of dicarboxylic acids. Next, we collected experimental values for a wide array of potentially associating species and carefully examined literature practices in reporting values these properties. We tested the applicability to advanced QSPR methods to the association problem. We discovered a highly accurate limit to liquid heat capacity for organic species. Finally, we test the abilities of advanced equations of state on associating chemicals. Based on these findings, several new methods were developed, and an updated approach to the derivative method was recommended to DIPPR. We have taken significant steps forward in DIPPR's ability to predict these properties. However, this work does not fully solve the problem of association in thermodynamic properties. In addition to the above work, significant work was performed in the field of autoignition, biomechanical sensors, and design of materials for non-linear optics.
College and Department
Ira A. Fulton College of Engineering and Technology; Chemical Engineering
BYU ScholarsArchive Citation
Bloxham, Joseph C., "Improving Predictions of Vapor Pressure, Liquid Heat Capacity, and Heat of Vaporization in Associating Fluids" (2022). Theses and Dissertations. 9463.
thermodynamics, prediction methods, experimental measurements