Date of Defense
14-4-2026 5:00 PM
Location
Room 1118, F1 Building
Document Type
Dissertation Defense
Degree Name
Doctor of Philosophy in Chemical Engineering
College
College of Engineering
Department
Chemical and Petroleum Engineering
First Advisor
Joy Tannous
Keywords
Free radicals; Radical stability; Temperature effects; Solvent effects; Radical quantification; Electron Spin Resonance (ESR) spectroscopy; Vegetable Oil; Frying Effect
Abstract
Free radicals are reactive species with unpaired electrons that occur and form within a range of biological, physical, and chemical systems. These highly reactive entities can interact with each other and/or with other molecules present in a mixture, often leading to significant changes in the system. Control over free radical concentration and free radical reactions is necessary in various fields depending on the aim of the process. For instance, free radical addition reactions play an essential role in the synthesis of polymers, where controlled radical behavior is necessary. However, in the thermal cracking of oil, free radical addition reactions are undesirable, as they interfere with the stability of products and lead to the formation of asphaltenes and other heavy products that cause equipment clogging. Control over free radicals and their interactions and reactions is crucial but is still immature especially in chemical systems. Although the influence of temperature on free radical concentrations in chemical reactions has been studied, temperature is only one of several factors that affect free radical mechanisms. The existing literature does not decently investigate other factors that may influence the behavior of free radicals in various systems. Additionally, accurately measuring and quantifying free radicals is challenging due to their highly reactive nature and short lifespans. This project will examine the effect of various solvents (i.e. the matrix) on the free radical concentration and radical stability. Samples will include a range of simple to complex radical systems and will be dissolved in a variety of solvents from different chemical families. In addition to solvent effects, the project will explore how storage conditions, including time and temperature, affect radical concentration across different types of free radicals. The study will also develop a methodology for free radical identification and quantification. Free radical concentrations in each setup will be analyzed using Electron Spin Resonance (ESR) spectroscopy, allowing for precise, real-time insights into these dynamic species. It is expected that this project will enhance the understanding of factors that influence free radical concentration, stability and behavior in various systems. The current work sets the basis on which free radical mechanisms of complex chemical systems are studied in the future.
Included in
Effects of Solvent Type, Storage Time, and Storage Temperature on Free Radical Stability and Concentration in Model Radical Systems and Complex Vegetable Oil Matrices
Room 1118, F1 Building
Free radicals are reactive species with unpaired electrons that occur and form within a range of biological, physical, and chemical systems. These highly reactive entities can interact with each other and/or with other molecules present in a mixture, often leading to significant changes in the system. Control over free radical concentration and free radical reactions is necessary in various fields depending on the aim of the process. For instance, free radical addition reactions play an essential role in the synthesis of polymers, where controlled radical behavior is necessary. However, in the thermal cracking of oil, free radical addition reactions are undesirable, as they interfere with the stability of products and lead to the formation of asphaltenes and other heavy products that cause equipment clogging. Control over free radicals and their interactions and reactions is crucial but is still immature especially in chemical systems. Although the influence of temperature on free radical concentrations in chemical reactions has been studied, temperature is only one of several factors that affect free radical mechanisms. The existing literature does not decently investigate other factors that may influence the behavior of free radicals in various systems. Additionally, accurately measuring and quantifying free radicals is challenging due to their highly reactive nature and short lifespans. This project will examine the effect of various solvents (i.e. the matrix) on the free radical concentration and radical stability. Samples will include a range of simple to complex radical systems and will be dissolved in a variety of solvents from different chemical families. In addition to solvent effects, the project will explore how storage conditions, including time and temperature, affect radical concentration across different types of free radicals. The study will also develop a methodology for free radical identification and quantification. Free radical concentrations in each setup will be analyzed using Electron Spin Resonance (ESR) spectroscopy, allowing for precise, real-time insights into these dynamic species. It is expected that this project will enhance the understanding of factors that influence free radical concentration, stability and behavior in various systems. The current work sets the basis on which free radical mechanisms of complex chemical systems are studied in the future.