University of Colorado, Boulder CU Scholar Chemical & Biological Engineering Graduate Chemical & Biological Engineering Theses & Dissertations Spring 1-1-2015 Design and Development of Room Temperature Ionic Liquid-Based Epoxy-Amine Resins and Ion Gels for Membrane-Based CO2 Separations William Michael McDanel University of Colorado Boulder, [email protected] Follow this and additional works at:https://scholar.colorado.edu/chbe_gradetds Part of thePolymer Chemistry Commons, and thePolymer Science Commons Recommended Citation McDanel, William Michael, "Design and Development of Room Temperature Ionic Liquid-Based Epoxy-Amine Resins and Ion Gels for Membrane-Based CO2 Separations" (2015).Chemical & Biological Engineering Graduate Theses & Dissertations. 76. https://scholar.colorado.edu/chbe_gradetds/76 This Dissertation is brought to you for free and open access by Chemical & Biological Engineering at CU Scholar. It has been accepted for inclusion in Chemical & Biological Engineering Graduate Theses & Dissertations by an authorized administrator of CU Scholar. For more information, please [email protected]. Design and Development of Room Temperature Ionic Liquid-Based Epoxy-Amine Resins and Ion Gels for Membrane-Based CO Separations 2 by William Michael McDanel B.S., North Carolina State University, 2010 A thesis submitted to the Faculty of the Graduate School of the University of Colorado in partial fulfillment of the requirement for the degree of Doctor of Philosophy Department of Chemical and Biological Engineering 2015 This thesis entitled: Design and Development of Room Temperature Ionic Liquid-Based Epoxy-Amine Resins and Ion Gels for Membrane-Based CO Separations 2 written by William Michael McDanel has been approved for the Department of Chemical and Biological Engineering Professor Douglas L. Gin Professor Richard D. Noble Date The final copy of this thesis has been examined by the signatories, and we Find that both the content and the form meet acceptable presentation standards Of scholarly work in the above mentioned discipline. ABSTRACT McDanel, William Michael (Ph.D., Chemical Engineering, Department of Chemical and Biological Engineering) Design and Development of Room Temperature Ionic Liquid-Based Epoxy-Amine Resins and Ion Gels for Membrane-Based CO Separations 2 Thesis directed by Professors Douglas L. Gin and Richard D. Noble Room temperature ionic liquids (RTILs) have very attractive CO permeabilities and 2 CO /light gas permeability selectivities as supported membranes. However, RTILs are displaced 2 as supported membranes by a pressure differential, rendering them useless. Polymerized RTILs (poly(RTIL)s) can be blended with unbound RTILs to form composite structures with good CO 2 permeabilities and CO /light gas permeability selectivities. High weight loadings of free RTILs 2 can be achieved with epoxy-amine chemistry to form ion gel membranes that have residual and formed amine groups that interact specifically with CO to provide enhanced CO transport. 2 2 Novel bis(epoxide)-functionalized RTIL monomers were synthesized and reacted with commercially available amine monomers to produce cross-linked, epoxy-amine-based poly(RTIL) resins and ion-gel membranes via step-growth (S-G) polymerization. The amine functionality was controlled by manipulating the S-G monomer stoichiometric ratios. Analysis of the gas permeation data revealed that these materials exhibit a rare case of inverse CO /CH 2 4 diffusion selectivity (D /D < 1) for ideal gas permeation testing. This phenomenon was CO2 CH4 attributed to the interaction of CO with residual and formed amine groups in the S-G PIL. 2 Structural changes to the length and chemical nature (i.e., alkyl vs. ether) between the imidazolium group and epoxide groups were studied to determine their effects on CO affinity. 2 The effect of using a primary vs. a secondary amine-containing multifunctional monomer was iii also investigated. Secondary amine monomers can increase CO permeability but also increase 2 the reaction time. By changing either epoxide or amine monomer structure, the CO solubility 2 and permeability of the resulting PIL resins and ion-gel membranes can be improved. The residual and formed amine functional groups in epoxy-amine ion gel membranes allow for the fixed-site-carrier facilitated transport of CO . As expected for materials operating 2 via the fixed-site facilitated transport mechanism, increased CO permeability and CO /N 2 2 2 selectivity was observed with decreasing CO partial pressure. The hydrophilicity of the free 2 RTIL was determined to play an important role, with more hydrophilic RTILs enhancing the effects of facilitated transport. Several of the membranes reported have CO /N separation 2 2 performance that exceeds the 2008 Robeson upper bound. Therefore, these represent promising materials and industrially attractive materials for membrane-based CO separations. 2 iv DEDICATION I would like to dedicate this thesis work to my wife and best friend, Katherine, for her love and support during my thesis work. As well as my parents, Greg and Tracey, I am lucky beyond words to be your son. ACKNOWLEDGEMENTS My financial support was provided by either the Department of Energy Advanced Research Projects Agency-Energy program (Grant DE-AR0000098) or Total (S.A) and is gratefully acknowledged. Without funding, research does not exist. I would like to acknowledge and thank my two thesis advisors, Douglas Gin and Richard Noble for their guidance, patience, and generosity over the course of my thesis work. The creative freedom and support offered was much appreciated. There were a number of opportunities I experienced that would have not been possible without such great advisors. There are a number of Gin and Noble group members who were essential to my thesis work. I would like to acknowledge Trevor Carlisle, who was my mentor during my first year. He truly “put me under his wing” and taught me many of the things I know about being successful. I would like to thank two undergraduate researchers, Anna Swanson and Jason Barton, who were the workhorses that helped me collect experimental data and explore new synthesis procedures. The comradery I was lucky to share during my graduate studies with Blaine Carter, Garret Nicodemus, Lee Miller, and Matt Cowan was much appreciated whenever I needed help and/or a beer when I was struggling in lab. It is impossible to not acknowledge and thank my family for their love and support throughout my graduate work. They have helped me step out of the academic bubble and see the other important parts of the world. Lastly, I would like to thank my loving and supportive wife, Katherine. Honestly, I wouldn’t have been able to do this without you. Thank you for your endless patience and support. vi Table of Contents List of Tables ..................................................................................................................... xi List of Figures .................................................................................................................. xii Chapter 1: Introduction ................................................................................................... 1 1.1 Background and overview .................................................................................................... 1 1.2 Room temperature ionic liquids for CO separations ........................................................... 4 2 1.3 Polymerized room temperature ionic liquids ....................................................................... 5 1.4 Epoxy resins ......................................................................................................................... 7 1.5 Overview of thesis research ................................................................................................. 8 1.6 References .......................................................................................................................... 10 Chapter 2: Cross-linked Ionic Resins and Gels from Epoxide-functionalized Imidazolium Ionic Liquid Monomers ............................................................................ 15 2.1 Introduction ........................................................................................................................ 16 2.2 Experimental ...................................................................................................................... 20 2.2.1 Materials and instrumentation .................................................................................... 20 2.2.2 Synthesis of bis(epoxide) IL monomer A and IL B ................................................... 21 2.2.2.1 Synthesis of 1,3-di(3-butenyl)imidazolium trifluoromethanesulfonimide (i) .......... 21 2.2.2.2 Synthesis of 1,3-bis(2-oxiranyl-ethyl)imidazolium trifluoromethanesulfonimide (A) ............................................................................................................................................... 22 2.2.3 Epoxide curing experiments ....................................................................................... 23 2.2.4 Carbon dioxide gas sorption measurements ............................................................... 23 2.2.5 Fabrication of cross-linked epoxy-amine PIL/IL ion-gel membranes ........................ 24 2.2.6 Ideal single-gas permeability, diffusivity, and solubility measurements and theory ..... .................................................................................................................................... 24 2.3 Results and discussion ........................................................................................................ 26 2.3.1 Discussion of monomer A synthesis .......................................................................... 26 2.3.2 Epoxy-amine PIL resin preparation ............................................................................ 27 2.3.3 Curing of neat epoxy-amine PIL resins and PIL/IL ion-gels ..................................... 29 2.3.4 Ideal carbon dioxide sorption testing .......................................................................... 32 2.3.5 Ideal CO /N and CO /CH permeation testing of prepared ion-gel membranes ........... 2 2 2 4 .................................................................................................................................... 34 2.3.6 CO /CH solubility and diffusivity selectivity ........................................................... 37 2 4 2.4 Summary ............................................................................................................................ 39 2.5 Acknowledgments .............................................................................................................. 40 2.6 References .......................................................................................................................... 40 2.7 Supplementary information ................................................................................................ 43 2.7.1 Calculated gel point conversion values (p ) using statistical theory and Carothers c gelation theory for S-G polymerizations ............................................................................ 44 2.7.2 Example FT-IR spectra of pre- and post-cured epoxy resins ..................................... 46 2.7.3 Carbon dioxide solubility measurements and method ................................................ 46 vii 2.7.4 Attempts to characterize composition of the amine groups present in the formed S-G epoxy-amine PIL networks ................................................................................................ 48 2.7.5 Comparison with previous PIL/IL ion gel systems..................................................... 50 2.7.6 Comprehensive transport data for the ion gel membranes reported herein ................ 52 Chapter 3: Effect of Monomer Structure on Curing Behavior, CO Solubility, and 2 Gas Permeability of Ionic Liquid-based Epoxy-amine Resins and Ion-gels .............. 53 3.1 Introduction ........................................................................................................................ 54 3.2 Experimental ...................................................................................................................... 56 3.2.1 Materials and instrumentation .................................................................................... 56 3.2.2 Synthesis of bis(epoxide) IL monomers A–D ............................................................ 57 3.2.2.1 Synthesis of 1,3-bis(2-oxiranyl-ethyl)imidazolium trifluoromethanesulfonimide (A) ............................................................................................................................................... 57 3.2.2.2 Synthesis of 1,3-bis-(2-oxiranylmethoxy-ethyl)-imidazolium trifluoromethanesulfonimide (B) .......................................................................................... 57 3.2.2.3 Synthesis of 1,1-[oxybis(2,1-ethanediyloxy-2,1-ethanediyl]bis[2-oxiranyl- ethyl]imidazolium trifluoromethanesulfonimide (C) ............................................................ 60 3.2.2.4 Synthesis of 1,1-bis-(2-oxiranyl-ethyl)-pyrrolidinium trifluoromethanesulfonimide (D) ......................................................................................................................................... 63 3.2.3 Epoxy-amine resin curing experiments ...................................................................... 64 3.2.4 CO gas solubility measurements ............................................................................... 65 2 3.2.5 Fabrication of epoxy-amine ion-gel membranes ........................................................ 65 3.2.6 Ideal single-gas permeability, diffusivity, and solubility measurements and theory . 66 3.3 Results and discussion ........................................................................................................ 67 3.3.1 Rationale for monomer selection ................................................................................ 67 3.3.2 Effect of bis(epoxide) IL monomer on curing rate and CO affinity of ionic epoxy- 2 amine resins and ion-gels .......................................................................................................... 68 3.3.2.1 Curing of epoxy-amine resins and ion-gels......................................................... 69 3.3.2.2 CO sorption of epoxy-amine resins ................................................................... 70 2 3.3.2.3 Gas permeability, solubility, and diffusivity of ion-gels with monomer B ........ 72 3.3.3 Effect of amine monomer (TAEA vs. TMAEA) on curing rate, CO solubility, and 2 gas permeability of epoxy-amine resins and ion-gels ............................................................... 74 3.3.3.1 Curing rate of epoxy-amine resins with TAEA vs. TMAEA .............................. 74 3.3.3.2 CO uptake capacities and resin properties for TAEA vs TMAEA resins ......... 76 2 3.3.3.3 Gas permeability, diffusivity, and solubility selectivity for TMAEA containing ion-gel membranes ................................................................................................................ 77 3.4 Summary ............................................................................................................................ 78 3.5 Acknowledgments .............................................................................................................. 79 3.6 References .......................................................................................................................... 79 3.7 Supplementary information ................................................................................................ 82 Chapter 4: Fixed-site-carrier Facilitated Transport of Carbon Dioxide Through Ionic-liquid-based Epoxy-amine Ion Gel Membranes ..................................................... 88 4.1 Introduction ........................................................................................................................ 89 4.2 Experimental ...................................................................................................................... 93 viii 4.2.1 Materials and Instrumentation .................................................................................... 93 4.2.2 Mixed-gas permeation tests ........................................................................................ 94 4.2.3 Fabrication of epoxy-amine ion-gel membranes ........................................................ 94 4.3 Results and Discussion ....................................................................................................... 96 4.3.1 Selection and preparation of epoxy-amine ion gels .................................................... 96 4.3.2 Mixed-gas permeation results ..................................................................................... 97 4.3.2.1 Effect of % RH on CO /N permeability and selectivity .................................... 97 2 2 4.3.2.2 Effect of CO partial pressure at either 40% or 95% RH .................................. 100 2 4.3.2.2.1 Permeation studies at 40% RH ......................................................................... 100 4.3.2.2.2 Permeation studies at 95% RH ......................................................................... 102 4.3.2.2.3 Effect of CO partial pressure on dry mixed-gas permeation studies ............... 105 2 4.3.3 Discussion of the effect of free RTIL on permeation data ....................................... 105 4.3.4 Discussion of the effect of epoxy-amine stoichiometry ........................................... 107 4.3.5 Comparison to ideal data and Robeson plot ............................................................. 107 4.4 Conclusions ...................................................................................................................... 108 4.5 Acknowledgements .......................................................................................................... 109 4.6 References ........................................................................................................................ 109 4.7 Supplementary information .............................................................................................. 112 4.7.1 Control ion gel membranes ....................................................................................... 113 4.7.2 Brief discussion regarding differences in observed CO permeability for the mixed- 2 gas permeation measurements to the ideal measurements ...................................................... 114 Chapter 5: Conclusion and Recommendations .............................................................. 116 5.1 Summary of thesis work ................................................................................................... 116 5.2 Recommendations ............................................................................................................ 118 5.2.1 Thin-film membrane formation ................................................................................ 118 5.2.2 RTIL-based epoxide-containing reactive polymers ................................................. 119 5.2.3 The dependence of permeability and selectivity with increasing temperature ......... 120 5.3 References ......................................................................................................................... 121 Chapter 6: Bibliography ...................................................................................................... 122 Appendix A: Vinyl-functionalized Poly(imidazolium)s: A Curable Polymer Platform for Cross-linked Ionic Liquid Gel Synthesis .................................................. 133 A.1 Introduction ...................................................................................................................... 133 A.2 Approach .......................................................................................................................... 135 A.3 Summary .......................................................................................................................... 140 A.4 Acknowledgements .......................................................................................................... 141 A.5 References ........................................................................................................................ 141 A.6 Supplementary information .............................................................................................. 142 A.6.1 Materials ................................................................................................................... 142 A.6.2 Instrumentation ......................................................................................................... 143 A.6.3 Synthesis of poly(chloromethylstyrene) (1) .............................................................. 144 A.6.4 Synthesis of 100% N-vinylimidazolium-functionalized curable poly(RTIL) 4 ....... 146 ix