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Base Stable and Basic Ionic Liquids for Catalysis

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Base Stable and Basic Ionic Liquids for Catalysis DOCTOR OF PHILOSOPHY Base stable and basic ionic liquids for catalysis McNeice, Peter Award date: 2020 Awarding institution: Queen's University Belfast Link to publication Terms of use All those accessing thesis content in Queen’s University Belfast Research Portal are subject to the following terms and conditions of use • Copyright is subject to the Copyright, Designs and Patent Act 1988, or as modified by any successor legislation • Copyright and moral rights for thesis content are retained by the author and/or other copyright owners • A copy of a thesis may be downloaded for personal non-commercial research/study without the need for permission or charge • Distribution or reproduction of thesis content in any format is not permitted without the permission of the copyright holder • When citing this work, full bibliographic details should be supplied, including the author, title, awarding institution and date of thesis Take down policy A thesis can be removed from the Research Portal if there has been a breach of copyright, or a similarly robust reason. If you believe this document breaches copyright, or there is sufficient cause to take down, please contact us, citing details. Email: [email protected] Supplementary materials Where possible, we endeavour to provide supplementary materials to theses. This may include video, audio and other types of files. We endeavour to capture all content and upload as part of the Pure record for each thesis. Note, it may not be possible in all instances to convert analogue formats to usable digital formats for some supplementary materials. We exercise best efforts on our behalf and, in such instances, encourage the individual to consult the physical thesis for further information. Download date: 25. Sep. 2021 Title: Base stable and basic ionic liquids for catalysis December 2019 Peter McNeice Supervisors: Dr. Andrew C. Marr Prof. Kenneth R. Seddon Dr. Patricia C. Marr School of Chemistry and Chemical Engineering Thesis for Doctor of Philosophy Abstract The use of ionic liquids for catalysis is widespread, including in industrial processes which are run on hundreds of tonnes scale. However the use of ionic liquids for basic catalysis is limited by the instability of many ionic liquids under basic conditions. We address the dual problems of ionic liquid instability under basic conditions and the lacuna of basic ionic liquids. New quinine based ionic liquids were synthesised, including what I believe to be the first reported example of a room temperature quinine based ionic liquid. The thermal stability of all the prepared quinine ionic liquids was greater than 200 °C. Hammett basicity was relatively high for the quinine ionic liquids and the trends in thermal stability, melting point and basicity were determined to depend on the hydrogen bonding within the ionic liquid network. These ionic liquids catalysed the Knoevenagel condensation between malononitrile and benzaldehyde and were able to be recovered and reused without a decrease in activity. More strongly basic ionic liquids were synthesised by developing a new class of binary basic i ionic liquids; [Pyrr1,4][NTf2]x[O Pr]1-x. These ionic liquids were found to be stable for at least 8 months which was attributed to small concentrations of [OiPr]-, along with interion attractions and slow ion diffusion, which prevented the self-attack of [OiPr]- on the cation. i [Pyrr1,4][NTf2]x[OH]1-x and [P6,6,6,6][C8SO3]x[O Pr]1-x ionic liquids were determined to be unstable. i The [Pyrr1,4][NTf2]x[O Pr]1-x ionic liquids catalysed the Knoevenagel condensation between benzaldehyde and malononitrile and also a range of aldol condensations. The ionic liquids were recovered but were unable to catalyse subsequent reactions. i Heterogenisation of [Pyrr1,4][NTf2]x[O Pr]1-x and [Pyrr1,4][NTf2]x[OH]1-x ionic liquids was achieved through the preparation of SILPS, gels, silica spheres. Heterogenisation of i [P6,6,6,6][C8SO3]x[O Pr]1-x ionic liquids was achieved through the synthesis of hydrotalcite composites. The heterogeneous catalysts were used to promote Knoevenagel, aldol and dehydration reactions. The gels, silica spheres and hydrotalcite composites were recovered by filtration and re-used without a decrease in activity. Silica sphere formation was autocatalytic and I believe this to be the first reported example of this process. 2 Heterogeneous water purification catalysts were synthesised through the entrapment of Fe-TAML® in ionic liquid gels and ionic liquid silica spheres. These materials catalysed the decomposition of dyes in water to a similar or greater extent than homogeneous Fe- TAML®. The gels were reused at least 5 times without a decrease in activity which combined with their flexible preparation could possibly allow their incorporated into existing water purification infrastructure. 3 Acknowledgements I would like to thank my supervisors Dr Andrew C. Marr and Dr Patricia C Marr for all their guidance and support throughout this project and for the good times we have had in and out of the lab. A special mention must be given to my supervisor Professor Kenneth R. Seddon for developing the concept of this project and for giving advice in the early stages. I would also like to thank the whole Marr group for their help in the lab over the past 4 years and for their friendship and encouragement. My family and in particular my parents are always there for me and I am especially grateful for their love and support. 4 Declaration All the work in this thesis was composed by and carried out by myself, in the laboratories of Queen’s University Belfast, between October 2016 and September 2019, except where acknowledged as collaborations with those named. 5 Abbreviations, acronyms and initialisations APTMOS (Aminopropyl)trimethoxysilane BET Brunauer–Emmett–Teller BJH Barrett-Joyner-Halenda CDCl3 Deuterated chloroform CHNS Elemental analysis COSY Correlation spectroscopy D2O Deuterium oxide d6-DMSO Deuterated dimethyl sulfoxane DABCO 1,4-diazabicyclo[2.2.2]octane DBU 1,8-diazabicyclo[5.4.0]undec-7-ene DCM Dichloromethane DMAP 4-dimethylaminopyridine DMSO Dimethyl sulfoxane DSC Differential scanning calorimetry ee Enantiomeric excess eq Equivalent Et3N Triethylamine EtOH Ethanol FTIR Fourier transform infrared GC Gas chromatography h Hours H_ Hammett basicity HMTA Hexamethylenetetramine 6 HSQC Heteronuclear single quantum coherence spectroscopy IL Ionic liquid IR Infrared K2CO3 Potassium hydroxide KH Potassium Hydride KOH Potassium hydroxide KOtBu Potassium tert-butoxide [Li(NTf2)] Lithium bistriflimide M Molar MeCN Acetonitrile MeMgCl Methylmagnesium chloride MeOH Methanol Me-THF 2-methyltetrahydrofuran min Minutes Mol Mole MS Mass spectroscopy n Moles NaOCD3 Deuterated sodium methoxide NaOD Sodium deuteroxide NaOH Sodium hydroxide NaOiPr Sodium iso-propoxide NaOMe Sodium methoxide nBuLi n-butyl lithium NHC N-heterocyclic carbene 7 NMR Nuclear magnetic resonance PhMgBr Phenylmagnesium bromide PPh3 Triphenyl phosphine ppm Parts per million RFM Relative formula mass RPM Revolutions per minute RT Room temperature SD Standard deviation SILP Supported ionic liquid phase TEMS Triethoxymethylsilane TEOS Tetraethylorthosilicate TGA Thermogravimetric analysis THF Tetrahydrofuran TMS Tetramethylsilane TsDPEN 1,2-diphenyl-1,2-ethylenediamine UV Ultraviolet XRD X-ray diffraction Anions and cations - [BF4] Tetrafluoroborate [BMIM]+ 1-butyl-3-methylimidazolium [BMMIM]+ 1-butyl-2,3-dimethylimidazolium [Br]- Bromide + [C4Py] Butylpyridinium - [C8SO3] Octanesulfonate 8 [Cl]- Chloride [DCA]- Dicyanamide [EMIM]+ 1-ethyl-3-methylimidazolium [EMMIM]+ 1,2-dimethyl-3-ethylimidazolium [EtPy]+ Ethylpyridinium - [H2PO4] Dihydrogen phosphate [Im]- Imidazolate + [N1,8,8,8] Methyltrioctylammonium + [N2,2,2,PS] Triethylammonium propanesulfone + [N3,3,3,3] Tetrapropylammonium + [N4,4,4,4] Tetrabutylammonium - [NTf2] Bistriflimide [Bis(trifluoromethane)sulfonimide] [OAc]- Acetate [OEt]- Ethoxide [OH]- Hydroxide [OiPr] iso-propoxide [OTf]- Trifluoroacetate (triflate) + [P6,6,6,14] Trihexyl tetradecylphosphonium - [PF6] Hexafluorophosphate + [Pyrr1,4] N,N-butylmethylpyrrolidinium Numbered compounds 1a 1-N-methyl quininium iodide ([MeQn][I] 1c 1-N-methyl quininium bistriflimide ([MeQn][NTf2] 2a 1-N-butyl quininium iodide ([C4Qn][I]) 9 2c 1-N-butyl quininium bistriflimide ([C4Qn][NTf2]) 3a 1-N-hexyl quininium iodide ([C6Qn][I]) 3c 1-N-hexyl quininium bistriflimide ([C6Qn][NTf2]) 4b 1-N-octyl quininium bromide ([C8Qn][Br]) 4c 1-N-octyl quininium bistriflimide ([C8Qn][NTf2]) 5b 1-N-ethyl methylether quininium bromide ([C1OC2Qn][Br]) 5c 1-N-ethyl methylether quininium bistriflimide ([C1OC2Qn][NTf2]) 6b 1-N-2-(2-methoxyethoxy)ethane quininium bromide ([C1OC2OC2Qn][Br]) 6c 1-N-2-(2-methoxyethoxy)ethane quininium bistriflimide ([C1OC2OC2Qn][NTf2]) 10 Contents† Abstract ................................................................................................................................... 2 Acknowledgements ................................................................................................................. 4 Declaration .............................................................................................................................. 5 Abbreviations, acronyms and initialisations .......................................................................... 6 1 Literature review ............................................................................................................ 19 1.1 Introduction to ionic liquids ..................................................................................
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