Abstract

Accurate thermophysical property data are essential for the design, optimization, and safe operation of chemical processes. Properties such as vapor pressure, enthalpy of vaporization, heat capacity, density, and autoignition temperature--which are among the properties studied in this work--are required for equipment sizing, process simulation, hazard assessment, and economic evaluation. A major focus of this dissertation is the application of multi-property thermodynamic consistency techniques to compounds that exhibit strong vapor-phase association. These methods improve confidence in recommended property values by enforcing rigorous thermodynamic relationships among ideal-gas heat capacity, liquid heat capacity, vapor and liquid densities, vapor pressure, and enthalpy of vaporization. While thermodynamic consistency techniques have been successfully applied to many chemical families, compounds such as carboxylic acids have historically posed significant challenges because existing associating equations of state inadequately represent heat capacity. This work develops a methodology that explicitly accounts for vapor-phase association, extending thermodynamic consistency analysis to systems that were previously beyond the reach of conventional approaches. To support these efforts, extensive differential scanning calorimetry (DSC) measurements were performed. Heat capacities, melting points, enthalpies of fusion, and glass transition temperatures were measured and analyzed for 34 industrially important chemicals with limited or unreliable literature data. Additionally, ASTM E2716 Methods A and B for heat capacity determination by Modulated DSC (MDSC) were systematically compared to identify previously underappreciated sources of experimental variability and recommend strategies to improve accuracy. This dissertation also addresses the prediction and measurement of autoignition temperature (AIT). An improved prediction method, termed the Seaton-Redd-Guffey (SRG) method, was developed, and new experimental AIT measurements were conducted to support model development and expand the availability of high-quality data. Collectively, this work advances the measurement, evaluation, and prediction of thermophysical and safety-related properties, contributing to safer and more efficient chemical process design.

Degree

PhD

College and Department

Ira A. Fulton College of Engineering; Chemical Engineering

Rights

https://lib.byu.edu/about/copyright/

Date Submitted

2026-08-03

Document Type

Dissertation

Keywords

thermodynamics, thermophysical properties, hydrogen bonding, equation of state, DSC, autoignition temperature, flammability

Language

english

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