Study of Vaporization Enthalpies and Vapor Pressures of Potential Environmental Pollutants by Correlation-Gas Chromatography

The focus of this dissertation is on the measurement and analysis of thermodynamic data, including vaporization, fusion, and sublimation enthalpies and vapor pressures of dialkyl phthalates, as well as aliphatic and aromatic primary and tertiary amines by correlation gas chromatography (CGC). These compounds are important industrial and pharmaceutical substances whose prolonged use and sometimes misuse with regards to their disposal has created an environmental concern. Thermodynamic properties, such as vaporization enthalpy and vapor pressure provide crucial information to numerous industries and fields of study that include the chemical and petrochemical industry, chemical engineering and environmental science. Dialkyl phthalates are essential industrial products, with various commercial applications including their use as plasticizers in plastics used for packaging of consumer products, medical applications and waste disposal, as well as for applications in cosmetics. This work establishes a set of reasonably self-consistent experimental values for thermodynamic properties in an area that has been characterized by numerous inconsistent values over the years. Many aliphatic and aromatic primary and tertiary amines are pharmaceutical compounds, often prescribed as ammonium salts for solubility reasons. This can lead to the production of the neutral parent species when unused portions are discarded in the environment. Widespread use of these materials has raised concerns over the environmental impact of improperly discarded medications. Prior to this work, the thermodynamic properties of many of the materials investigated in this study were simply unavailable. Variants of some gas chromatographic methods have recently come under criticism and an additional focus of this thesis was to evaluate the limitations of the technique we employed for these measurements. Comparisons to other related methods were made in an effort to evaluate both the strengths and weaknesses of the current technique, correlation gas chromatography. During the course of these studies, some significant advances in the understanding of the applicability and versatility of this method have been achieved