In-situ spectroscopic studies of the mechanism of solid super-acid catalysed methanol carbonylation Lee D. Dingwall Submitted for the degree of Doctor of Philosophy University of York Department of Chemistry July 2010 Acknowledgements I would like to thank BP Chemicals and the EPSRC for funding this PhD research. For Supervision and helpful discussions throughout the project, thanks go to Professor Adam Lee, Dr Karen Wilson and Dr Jason Lynam at the University of York and Drs Jon Deeley, Glenn Sunley and David Law (and the rest of my colleagues at BP Chemicals) at the BP Chemicals site in Hull. Thank you to Durham Solid State NMR service, the Swansea Mass Spectrometry Service, MEDAC and Dr Nigel Young for providing some analytical data discussed herein. I would also like to thank The University of York Chemistry workshops for support with construction and maintenance of in-house equipment, as well as Drs Luca Olivi and Andrea Cognigni for their support with XAFS measurements at the Sincrotrone in Trieste. Thank you to the University of York for providing a comfortable and dynamic environment for my personal development, and all of my colleagues and friends (of whom there are too many to mention here, but are written in white ink in the background of this thesis – as promised) who made my time so enjoyable. On the academic side, I would particularly like to thank the York Surface Science and Catalysis group who have recently moved to join the Cardiff Catalysis Institute and the SLUG research group, and wish all current members every success for the future. From my ‘extra curricular activities’ I would like to thank all members of the Chemical InterActions society, the York Student Cinema and the York Boxing Club as well as the Science Club volunteers team for enriching my life and helping me to refocus my thoughts after becoming ‘over-immersed’ in my research. Special thanks go to Dr Andrew Newman for invaluable discussions and ‘handing over the torch’ for further development of some of the outcomes of his PhD research. Thanks go to James Naughton, Janine Montero and Christine Welby for editing suggestions throughout the thesis. Returning home after a day in the lab was always a pleasure in York thanks to Halifax College flatmates and Dr Jonny Gammon and Alan Burns who have been like brothers and have always provided a warm, friendly and entertaining place to go back to. As for all of my successes, my parents and brother Paul are always deeply rooted at the heart. For my fiancée Anne-Cécile, you’re with me through all of life’s adventures, and on this long and winding path, through blue skies and stormy clouds - I couldn’t have done it without you. ii Declaration I confirm that all work in this doctoral thesis is the soul work of the author unless otherwise stated. Some research reported in this manuscript has been or is in preparation to be published in peer reviewed journal articles referenced below. 1. A polyoxometallate-tethered Ru complex as a catalyst in solventless terminal alkyne oligomerization L. D. Dingwall, C. M. Corcoran, A. F. Lee, L. Olivi, J. M. Lynam and K. Wilson, Catalysis Communications, 2008, 10, 53-56. 2. Bifunctional organorhodium solid acid catalysts for methanol carbonylation L. D. Dingwall, A. F. Lee, J. M. Lynam, K. Wilson, L. Olivi, J. M. S. Deeley, S. Gaemers, G. J. Sunley – in preparation. iii Table of Contents Acknowledgements ................................................................................................. ii Declaration ............................................................................................................. iii Table of Contents ................................................................................................... iv Table of Figures ................................................................................................... viii Table of Tables ..................................................................................................... xix Table of Equations ............................................................................................... xxi Table of Schemes ................................................................................................ xxii Abstract .............................................................................................................. xxiii Abbreviations ...................................................................................................... xxv Chapter 1 - Introduction .......................................................................................... 1 1.1 - Catalysis .......................................................................................................... 2 1.2 - Heterogeneous Catalysis ................................................................................. 4 1.2.1 - Heterogeneous acid catalysis ....................................................................... 5 1.3 - Deactivation in heterogeneous catalysts ......................................................... 7 1.3.1 - Key causes of deactivation .......................................................................... 8 1.4 - Catalyst lifetime .............................................................................................. 9 1.5 - Acetic Acid ................................................................................................... 10 1.6 - Acetic Acid production from methanol carbonylation ................................. 10 1.7 - Multidentate Phosphine ligands in Catalysis ................................................ 17 1.8 - Polyoxometallates ......................................................................................... 21 1.8.1 - Chemistries involving the use of polyoxometallates (POMs) ................... 22 1.9 - Heteropolyacids ............................................................................................ 25 1.9.1 - Structure and Properties ............................................................................. 25 1.9.2 - Keggin reaction mechanism ...................................................................... 27 1.10 - Supported HPA materials ........................................................................... 28 1.11 - Synthetic challenges of organic-inorganic hybrid polyoxometallates materials ................................................................................................................ 28 1.12 - Project Aims ............................................................................................... 29 1.13 - References ................................................................................................... 30 Chapter 2 - Experimental ...................................................................................... 36 iv 2.1 - Characterisation ............................................................................................ 36 2.1.1 - Thermogravimetric Analysis TGA and Differential thermal analysis ....... 36 2.1.2 - Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) 37 2.1.3 - Raman Spectroscopy.................................................................................. 39 2.1.4 - Powder X-ray Diffraction .......................................................................... 39 2.1.5 - Single Crystal XRD ................................................................................... 40 2.1.6 - X-Ray Photoelectron Spectroscopy (XPS) ................................................ 40 2.1.7 - X-Ray absorption spectroscopy (XAS) ..................................................... 43 2.1.8 - In-situ XANES ........................................................................................... 46 2.1.9 - Porosimetry ................................................................................................ 47 2.1.10 - Solution state NMR ................................................................................. 48 2.1.11 - Structural MS analysis ............................................................................. 49 2.1.12 - Solid state MAS-NMR ............................................................................ 49 2.1.13 - ICP-MS and CHN elemental analysis ..................................................... 49 2.1.14 - Pyridine titrations ..................................................................................... 49 2.1.15 - Methanol carbonylation tests ................................................................... 50 2.1.16 - Dimethyl ether carbonylation tests .......................................................... 53 2.1.17 - Ethanol dehydration tests ......................................................................... 53 2.1.18 - Phenyl acetylene oligomerisation tests .................................................... 53 2.2 - Synthesis of Ru Compounds ......................................................................... 55 2.2.1 - Synthesis of Ru(Cl)(Cp)(PPh3)2 ................................................................ 55 2.2.2 - Synthesis of RuHPW ................................................................................. 56 + 3- 2.2.3 - Synthesis of [NEt3H] 3.[PW12O40] (NEt3HPW) ...................................... 57 2.2.4 - Synthesis of Ru(Cl)(Cp)(dppe) .................................................................. 57 2.2.5 - Synthesis of ‘RudppeHPW’ compound ..................................................... 58 2.3 - Synthesis of Rh compounds .........................................................................