THE DEVELOPMENT OF CO -SWITCHABLE TECHNOLOGIES 2 FOR SEPARATION OF ORGANIC COMPOUNDS by Sean M. Mercer 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 December, 2012 Copyright © Sean M. Mercer, 2012 Abstract The increasing environmental impact of society has created the need for the modification of current and the implementation of new industrial processes which are less environmentally harmful. However, these new or modified processes must be less material-, time-, and cost-intensive such that they are more economically beneficial than the processes they are to supplant. The described research was inspired by these two ideas and is comprised of two projects, both focused on the creation of recyclable, CO - 2 switchable methods of separating organic compounds. The development and optimization of switchable water, a CO -switchable ionic 2 strength aqueous solvent is described. The solvent system, an amine/aqueous mixture, had the ability to switch from low to high ionic strength via the application and removal of CO . This solvent system was able to achieve salting-out of water-miscible organics in 2 comparable amounts to several inorganic salts typically used for salting-out. The switchable water system was explored for use in several industrial applications. A homogeneous catalysis recycling system was developed for the hydroformylation of styrene. A catalyst was able to be recovered and recycled five times with minimal loss of activity. The use of switchable water to expedite the settling of clay suspensions was also explored. Switchable water, when used as process water did not settle bulk clay solids as quickly as a CO -only treatment, but did however increase the 2 settling rate of small clay fines resulting in lower turbidities of the supernatant. The solvent could be recovered from settled clay suspensions and recycled up to three times. Finally, efforts towards the realization of CO -switchable chiral resolving agents 2 are presented. It is hypothesized that chiral nitrogenous bases could be used as switchable ii resolving agents by forming diastereomeric salt pairs with racemic alcohols via the application of CO . After separation of the diastereomers, removal of CO would afford 2 2 the resolved alcohol enantiomers and the chiral base. Efforts towards the synthesis of a library of chiral nitrogenous bases and the screening of their reactivity with CO -treated 2 alcohols are described. Several bases were generated, but the necessary reactivity between the bases and the racemic alcohols in the presence of CO was not observed. 2 iii Acknowledgements During the past four years at Queen's I've been extremely fortunate to make many new friends and to truly grow as a scientist and as a person. I would first like to thank Professor Jessop for his guidance and mentorship. Your knowledge, enthusiasm, and eagerness to teach (or to let me figure it out for myself) has instilled me with an even greater passion for research, science, and the environment. I would be remiss to not extend gratitude to the many academic and industrial collaborators that I had the opportunity to work with. I am also very thankful for the generous support of many government and industrial agencies that supported my work as well as the Department of Chemistry at Queen's, particularly the faculty and support staff that served as mentors, readers, and supervisory committee members. My colleagues in the Jessop group have been an absolute pleasure to work, play, and commiserate with. I'd specifically like to thank Trisha Ang, Alaina Boyd, Vanessa Little, and Darrell Dean whom I had the great privilege to have as friends for the entirety of my time in Kingston. I would also like to specifically thank the people that greatly influenced me during my time at Queen's. Drs. Tobias Robert, Dominik Wechsler, Keith Huynh, and Jitendra Harjani, you have all provided with so much help for the future by showing me how excellent scientists conduct themselves. I'd like to thank my friends and family whom have been constantly supportive of me despite my 8+ year (and growing) reluctance to get a real job. I would especially like to thank my Mom and Dad whom instilled me with a love of science and learning at a very young age. I love you both! iv Finally, I would like to thank my beautiful and inspiring wife, Victoria. You have been my biggest supporter and I will never be able to thank you enough for the sacrifices that you've made so that I could pursue my dreams. I am the luckiest man in the world to have you in my life and I hope that our lives together will continue to be full of fun, love, laughter, and highly-cited journal publications. I hope that in the future that I will be able pay forward the mentorship, friendship, and love that I have been fortunate enough to receive during these past several years. Slainte Mhath! v 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. Any and all contributions from collaborators are clearly noted below. In Chapter 3, Mr. Daniel Dixon and Mr. Chien-Shun Chen participated in the data collection of organic compound salting out. Dr. Jitendra Harjani and Ms. Zahra Ghoshouni developed a preliminary procedure for the synthesis of compound 3.11, which was later modified. Dr. Tobias Robert synthesized and studied compounds 3.1 and 3.10. Prof. Natalie Cann assisted with computational calculations. Prof. Gilles Peslherbe and Mr. Soran Jahangiri of Concordia University participated in the formulation of hypotheses and development of the final conclusions as to what factors dictate the salting out behaviour of diammonium salts in aqueous solution. In Chapter 4, Dr. Tobias Robert and Mr. Daniel Dixon participated in method development and screening of pre-catalysts. Dr. Alemayehu Asfaw and Prof. Diane Beauchemin performed the ICP-MS measurements. In Chapter 5, Dr. Tobias Robert and Mr. Chien-Shun Chen participated in data collection of clay settling. Ms. Ying Lau contributed to the initial method development and zeta potential measurements. The results of her initial study are presented in their entirety in her M.Sc. thesis (Queen’s University, Sept. 2010). Mr. Ian Rupar assisted with light microscopy. vi In addition, all X-ray structures described were solved by Dr. Ruiyao Wang and all high-res mass spectra were collected by Dr. Jiaxi Wang and Mr. James Lei at Queen’s University. Portions of the dissertation have been published previously: Chapter 2: i) S. M. Mercer, P.G. Jessop, ChemSusChem 2010, 3, 467-470. Reproduced with permission of John Wiley & Sons, 2012. Chapter 3: i) S.M. Mercer, T. Robert, D.V. Dixon, C-S. Chen, Z Ghoshouni, J.R. Harjani, S. Jahangiri, G.H. Peslherbe, P.G. Jessop, Green Chemistry 2012, 14, 832-839. Reproduced with permission of the Royal Society of Chemistry, 2012. Chapter 4: i) S.M. Mercer, T. Robert, D.V. Dixon, P.G. Jessop, Catalysis Science & Technology 2012, 2, 1315-1318. Reproduced with permission of the Royal Society of Chemistry, 2012. Chapter 5: i) C-S Chen, Y-Y. Lau, S.M. Mercer, T. Robert, J.H. Horton, P.G. Jessop, ChemSusChem 2012, DOI: 10.1002/cssc.201200465. Reproduced with permission of John Wiley & Sons, 2012. Sean M. Mercer December, 2012 vii Table of Contents Abstract ii Acknowledgements iv Statement of Originality vi Table of Contents viii List of Figures xii List of Tables xiv List of Abbreviations xvi List of Symbols xviii List of Numbered Compounds xx Chapter 1 • Introduction 1.1 • Green Chemistry 1.1.1 • Ideals & Principles 1 1.1.2 • Metrics 3 1.1.3 • Practice in Industry 6 1.2 • Carbon Dioxide 1.2.1 • Background, Structure & Bonding 8 1.2.2 • Reactivity 10 1.3 • CO -Switchable Technologies 2 1.3.1 • Switchable Materials 15 1.3.2 • CO -Switchable Solvents 15 2 1.3.3 • CO -Switchable Surfactants 19 2 1.3.4 • CO -Switchable Polymers 20 2 1.3.5 • CO -Switchable Particles 21 2 1.3.6 • CO -Switchable Catalysts & Solutes 23 2 1.3.7 • Future Technologies 24 1.4 • Electrolyte Solutions 1.4.1 • Ideal, Non-ideal Solutions & Activity 24 1.4.2 • Formulation of the Ionic Strength Term 27 viii 1.4.3 • Effects of Ionic Strength 29 1.5 • Separation of Chiral Compounds 1.5.1 • Methods of Obtaining Enantio-enriched Compounds 33 1.5.2 • Chiral Resolution by Crystallization 35 1.6 • Research Objectives 37 1.7 • References 37 Chapter 2 • The Development of Switchable Water 2.1 • Introduction 47 2.2 • Results and Discussion 2.2.1 • Confirmation of Additive Reversibility 51 2.2.2 • Polybasic Amines 56 2.2.3 • Salting Out Studies 58 2.3 • Conclusions 61 2.4 • Experimental 62 2.5 • References 65 Chapter 3 • Design, Synthesis and Solution Behaviour of Switchable Water Additives 3.1 • Introduction 67 3.2 • Results and Discussion 3.2.1 • Comparison of Salting Out Efficiencies 69 3.2.2 • Basicity Considerations 71 3.2.3 • Long-Linker Bolaform Electrolytes 74 3.2.4 • Accounting for the Diminishing Salting Out Effect 76 3.2.5 • New Switchable Water Additives 86 3.2.6 • Primary and Secondary Amines as Switchable Water Additives 90 3.3 • Conclusions 95 3.4 • Experimental 97 3.5 • References 107 ix Chapter 4 • Recycling of Homogeneous Catalysts Using Switchable Water 4.1 • Introduction 112 4.2 • Results and Discussion 4.2.1 • General Concept 114 4.2.2 • Initial Hydroformylation Studies 117 4.2.3 • Optimization of the Hydroformylation Reaction 118 4.2.4 • Regioselectivity Issues 126 4.2.5 • Additional Catalytic Reactions 130 4.3 • Conclusions 131 4.4 • Experimental 132 4.5 • References 134 Chapter 5 • The Effect of Switchable Water on Clay Suspensions 5.1 • Introduction 137 5.2 • Results and Discussion 5.2.1 • The Effect of TMDAB on Kaolinite Suspensions 139 5.2.2 • The Effect of Clay Loading on Kaolinite Suspensions 147 5.2.3 • The Effect of pH and Ionic Strength on Kaolinite Suspensions 150 5.2.4 • Recycling Studies 158 5.2.5 • The Effect of TMDAB on Montmorillonite Suspensions 162 5.3 • Conclusions 164 5.4 • Experimental 166 5.5 • References 171 Chapter 6 • Towards the Development of CO -Switchable Chiral Resolving 2 Agents 6.1 • Introduction 173 6.2 • Results and Discussion 6.2.1 • Chiral Imidazoline Frameworks 177 6.2.2 • Cinchona Alkaloid-Based Amidines 180 6.2.3 • Other Amidine and Guanidine Frameworks 184 x