IMPROVEMENTS IN THE PERFORMANCE AND UNDERSTANDING OF SWITCHABLE-HYDROPHILICITY SOLVENTS by Jesse R. Vanderveen A thesis submitted to the Department of Chemistry In conformity with the requirements for the degree of Doctor of Philosophy Queen’s University Kingston, Ontario, Canada April, 2018 Copyright © Jesse R. Vanderveen, 2018 Abstract Switchable-hydrophilicity solvents (SHSs) are amine and amidine solvents that can be reversibly switched between two forms: one that forms a biphasic mixture with water and another that forms a monophasic mixture with water. The addition or removal of CO2 from SHS-based systems acts as the trigger to switch between these two forms. SHSs have attracted attention as alternative solvents for a variety of applications because their switchable behaviour allows them to be used in energy- or material- efficient ways. One such application is distillation-free solvent- solute separations. The present research builds an understanding of the properties of amines that determine whether they are SHSs or not. It also applies this understanding to the development of new SHSs with fewer health and environmental hazards, such as decreased acute toxicity and decreased volatility, as well as improved performance with respect to solvent-solute separations. The relationship between the pKaH and log Kow of an amine and the ability of the amine to act as a SHS is established. A mathematical model is described that can be used to predict whether an amine acts as a SHS based on these two properties. Furthermore, the influence of CO2 partial pressure and the water/amine volume ratio on these pKaH and log Kow requirements are investigated. The model acts as a guide when identifying new SHSs. Many new SHSs are identified with a variety of beneficial properties. SHSs that have oxygen-containing functional groups have decreased environmental, health, and safety risks than trialkylamine SHSs. Secondary amine SHSs are shown to switch to their hydrophilic state more rapidly than tertiary amine SHSs. Diamine SHSs can be more completely separated from solutes than monoamines, resulting in a more pure isolated solute after a SHS-based separation. A virtual screening approach to the design of SHSs is presented that can be used to rapidly screen thousands of compounds to identify those that are estimated to be SHSs with few environmental, health, and safety risks. The identification of new SHSs increases the options when selecting a solvent for a SHS-based process and provides data to improve the understanding of SHSs. ii Acknowledgements My graduate studies at Queen’s has been a wonderful experience. The people I’ve come to know during my studies have been a major part of this experience and the parts they played in the creation of this thesis must be acknowledged. First, I thank my supervisor Philip Jessop for his support, guidance, and advice over the course of my studies. His input was invaluable to my research. His passion for green chemistry and the responsible use of chemical technologies was and remains an inspiration to me. I also thank the members of the Jessop group, past and present, for creating a positive work environment. Everyone has been open for fruitful scientific discussions and the sharing of ideas with me since the day I joined. I have enjoyed discussing the problems being faced for various projects and enjoyed more the solutions we came up with, whether they were successful, elegant, impractical, or even bizarre. I hope this practice continues long into the future. I thank Jeremy Durelle specifically for sharing the SHS project with me for two years. It was a pleasure working with him and many of my successes stem from his work. I thank all of my collaborators for assisting me with their expertise in fields of study which I am less familiar with. I thank Switchable Solutions, Inc. for its financial support throughout my studies and Lowy Gunnewieck for his inputs to my work and his enthusiasm for my results. I am also grateful for financial support from the government of Ontario and the Natural Sciences and Engineering Research Council of Canada. Finally, I thank my family. I would not be who I am today without you. Your constant love and support is a true blessing. iii Statement of Originality I hereby certify that all of the work described within this thesis is the original work of the author. Any published (or unpublished) ideas and/or techniques from the work of others are fully acknowledged in accordance with the standard referencing practices. The contributions from collaborators are clearly noted below. All of the work was performed under the supervision of Dr. Philip Jessop. In Chapter 2, Jeremy Durelle contributed some data regarding the behaviour of some of the tertiary amines. The X-ray crystallography data was collected and interpreted by Dr. Jai- sheng Lu. In Chapter 3, Jeremy Durelle developed the models describing the two-component and three-component system with my input and assistance. Courtney B. Chalifoux and Julia E. Kostin helped with the optimization of these models. The data used to develop the models was collected by Jeremy Durelle, Yi Quan, and myself. I derived the equations used to calculate the fraction of protonation presented in section 3.4. In Chapter 4, the software used to screen the structures was developed by Dr. Luc Patiny. Courtney B. Chalifoux and Michael J. Jessop helped in the literature search for amines with experimentally determined properties relevant to the article. In Chapter 5, Roberto I. Canales determined the values for the non-random two-liquid model presented in the chapter under the supervision of Dr. Mark A. Stadtherr and Dr. Joan F. Brennecke using experimental data I collected with the assistance of Yi Quan and Courtney B. Chalifoux. In Chapter 6, Jialing Geng and Susanna Zhang tested compounds for switchable hydrophilicity under my supervision. Chemical syntheses were also performed by Jialing Geng and Susanna Zhang when required. iv Portions of this thesis have been published previously: Chapter 2: J. R. Vanderveen, J. Durelle, and P. G. Jessop, Green Chem., 2014, 16, 1187- 1197. Reproduced with the permission of the Royal Society of Chemistry. Chapter 3: i) J. Durelle, J. R. Vanderveen, and P. G. Jessop, Phys. Chem. Chem. Phys., 2014, 16, 5270-5275. Reproduced with the permission of the Royal Society of Chemistry. ii) J. Durelle, J. R. Vanderveen, Y. Quan, C. B. Chalifoux, J. E. Kostin, and P. G. Jessop, Phys. Chem. Chem. Phys., 2015, 17, 5308-5313. Reproduced with the permission of the Royal Society of Chemistry. iii) A. K. Alshamrani, J. R. Vanderveen, and P. G. Jessop, Phys. Chem. Chem. Phys., 2016, 18, 19276-19288. Reproduced with the permission of the Royal Society of Chemistry. Chapter 4: J. R. Vanderveen, L. Patiny, C. B. Chalifoux, M. J. Jessop, and P. G. Jessop, Green Chem., 2015, 17, 5182-5188. Reproduced with the permission of the Royal Society of Chemistry. Chapter 5: J. R. Vanderveen, Roberto I. Canales, Y. Quan, C. B. Chalifoux, M. A. Stadtherr, J. F. Brennecke, P. G. Jessop, Fluid Ph. Equilibria, 2016, 409, 150-156. Reproduced with the permission of the Elsevier. Jesse R. Vanderveen February, 2018 v Table of Contents Abstract ............................................................................................................................................ ii Acknowledgements ......................................................................................................................... iii Statement of Originality .................................................................................................................. iv List of Figures ................................................................................................................................. xi List of Tables ................................................................................................................................ xvi List of Symbols and Abbreviations ............................................................................................. xviii Chapter 1 .......................................................................................................................................... 1 1.1 Green Chemistry .................................................................................................................... 1 1.2 Solvents .................................................................................................................................. 5 1.3 CO2 ......................................................................................................................................... 9 1.4 Switchable hydrophilicity solvents ...................................................................................... 12 1.5 Objectives ............................................................................................................................ 17 1.6 References ............................................................................................................................ 18 Chapter 2 Design and Evaluation of Switchable-Hydrophilicity Solvents .................................... 23 2.1 Introduction .......................................................................................................................... 23 2.2 Results and discussion ......................................................................................................... 28 2.2.1 Refining the acceptable pKaH and log Kow ranges for amine SHSs ..............................