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Selective Oxidation of Polynuclear Aromatic Hydrocarbons

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Selective Oxidation of Polynuclear Aromatic Hydrocarbons SELECTIVE OXIDATION OF POLYNUCLEAR AROMATIC HYDROCARBONS Thesis submitted in accordance with the requirements of Cardiff University for the degree of Doctor of Philosophy EWA NOWICKA July 2012 DECLARATION This work has not been submitted in substance for any other degree or award at this or any other university or place of learning, nor is being submitted concurrently in candidature for any degree or other award. Signed ………………………………………… (candidate) Date ................................. STATEMENT 1 This thesis is being submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Signed ………………………………………… (candidate) Date ………………………… STATEMENT 2 This thesis is the result of my own independent work/investigation, except where otherwise stated. Other sources are acknowledged by explicit references.The views expressed are my own. Signed ………………………………………… (candidate) Date ………………………… STATEMENT 3 I hereby give consent for my thesis, if accepted, to be available for photocopying and for inter-library loan, and for the title and summary to be made available to outside organisations. Signed ………………………………………… (candidate) Date ………………………… STATEMENT 4: PREVIOUSLY APPROVED BAR ON ACCESS I hereby give consent for my thesis, if accepted, to be available for photocopying and for inter-library loans after expiry of a bar on access previously approved by the Academic Standards & Quality Committee. Signed ………………………………………… (candidate) Date ………………………… “You never fail until you stop trying.” Albert Einstein Abstract This thesis targets the selective oxidation of polynuclear aromatic compounds, which is considered as a preliminary step of upgrading of heavy oils, resids and bitumens to higher value materials in the liquid phase using different catalytic systems. Oxidation studies concentrated on simple model polyaromatic compounds and their alkylated derivatives. Ruthenium ion catalyzed oxidation chemistry has the potential to selectively oxidize PAHs and this system was studied in great detail with particular attention made to the reaction solvent system. Through careful studies it was found that the use of a monophasic solvent system led to the selective oxidative opening of an aromatic ring to produce the dialdehyde derivative. It was demonstrated that under standard conditions the rate of oxidation increased with the size of the fused ring system. 1H NMR methodology was developed to quantify the percentage of alkyl chain hydrogens preserved after reaction. It was found that the ruthenium based system demonstrated a high affinity for the oxidation of aromatic carbon with a low tendency to oxidise aliphatic carbon. These studies formed the basis of a detailed investigation into the mechanism of ruthenium ion catalyzed oxidation of PAHs. Investigation into another catalytic system which uses a homogeneous tungsten catalyst with hydrogen peroxide as the oxidant was also performed. Early studies showed that the H2WO4/H2O2 catalytic system exhibits high solvent dependant selectivity towards preferential oxidation of aromatic carbon. What is more, studies using alkylated aromatics with a alkyl chain greater than C8 showed that even in a non polar solvent the selectivity of oxidation is directed towards the aromatic carbon. A range of catalytic systems containing tungsten, ruthenium, heteropolyacids and their heterogenised equivalents were also applied to the oxidation of PAHs. Au-Pd supported catalysts in combination with molecular oxygen and H2WO4 were also used for the oxidation of PAHs and the results obtained opened a new path in the research of PAHs. Studies on the oxidative desulfurization, denitrogenation of heteroaromatics and the demetallation of nickel and vanadium porphyrines was also performed and are reported in this thesis. i Acknowledgement First of all I would like to express my heartfelt gratitude to my first research supervisor, Dr Stuart H. Taylor, for his support, valuable guidance throughout the period of my research and all suggestions and corrections related to my thesis. A special thank you goes to my co-supervisor, Prof. Graham J. Hutchings, whose knowledge and positive attitude towards life always put me in a better mood. I sincerely thank both of them for offering me the opportunity to study in Cardiff. I also would like to say thank you to my industrial sponsor, Dr Manuel A. Francisco, who turned out to be not only a good partner in collaboration but also a great friend of Polish culture. I am grateful for all the support and help given to me during the last 3 years. I also would like to acknowledge ExxonMobil for Ph.D. funding. Thanks must be given to Dr David Willock, and Prof. David Knight for their valuable advice. I am very happy to acknowledge my post doc, Dr Sankar M. Sundaram, amazing personality, brilliant researcher and my friend, who always encouraged me to do more work, gave me positive energy and made my life in Cardiff more colourful. Special thank you goes to Dr Robert L. Jenkins, who always believes that everything is possible, especially in the field of analysis. I am not able to express my gratitude toward him for all the long hours spent on my thesis corrections. Many thanks go to the boys from the GC-MS room, Robin and Dave. It gives me great pleasure to thank my labmates and friends, who made Cardiff a memorable place, especially: Ragini, Benoit, Jean-Philipe, Julie and Polina. Several people I would like to mention because they deserve a special thank you: Tomos Clarke for help during summer 2010, Scott Davies for support while printing the thesis, Dr Julia Rogan and Dr Barry Dean for being the most helpful couple in the world, Dr Tatyana Kotionova for 'laugh and cry' times, Piotr Rutkowski for chasing me with the mechanism of SN1 and SN2, Dr James Wixey for showing me the real face of British life and Niamh Hickey for introducing me to theoretical chemistry, bell ringing and knitting. Words are not enough to express my love and gratitude to my fiancée, Jakub for his passion, support and perseverance in loving me. Finally I would like to thank my parents for the help and love they have given me over my stay in the UK. Dziękuję. ii Glossary AAS Atomic Absorption Spectroscopy BET (Brunauer, Emmett, Teller) Surface Area Analysis COSY Correlation NMR Spectroscopy DMSO Dimethyl Sulfoxide GC Gas Chromatography HMBC Heteronuclear Multiple Bond Correlation HPLC High Performance Liquid Chromatography HR-MS High Resolution Mass Spectrometry LR-MS Low Resolution Mass Spectrometry HSQC Heteronuclear Single-Quantum Correlation Spectroscopy ICP-MS Inductively Coupled Plasma Mass Spectrometry IR Infrared Electromagnetic Radiation MS Mass Spectroscopy NiTPP Nickel (II) tetraphenylporphyrin NMR Nuclear Magnetic Resonance RICO Ruthenium Ion Catalyzed Oxidation SEM Scanning Electron Microscopy TBAB Tetra-n-butylammonium Bromide TBAF Tetra-n-butylammonium Fluoride TBHP Tert-butyl Hydrogen Peroxide TEM Transmission Electron Microscopy TPP 5,10,15,20-Tetraphenyl 21H,23H-porphine UV-Vis Ultraviolet-Visible Electromagnetic Radiation Spectroscopy VOTPP Vanadyl tetraphenylporphyrin XPS X-Ray Photoelectron Spectroscopy XRD X-Ray Diffraction iii Nomenclature IUPAC Name in THESIS Structure 9,10-Dioxo-9,10- Pyrene-4,5-Dialdehyde- dihydrophenanthrene-4,5- 9,10-Dione dialdehyde Biphenyl-2,2’,6,6’- Pyrene-4,5,9,10- tetraaldehyde Tetraaldehyde 2’,6,6-Triformyl-2- Pyrene-4,5,9-Trialdehyde- carboxylic acid 10-Monoacid 6,6’-Diformylbiphenyl-2,2’- Pyrene-4,5-Dialdehyde- diacarboxylic acid 9,10-Diacid 6’-Formylbiphenyl-2,2’,6- Pyrene-4-Monoaldehyde- tricarboxylic acid 5,9,10-Triacid Biphenyl-2,2’,6,6’- Pyrene-4,5,9,10-Tetraacid tetracarboxylic acid iv Nomenclature IUPAC Name in THESIS Structure 5-Formyl-9,10-dioxo-9,10- Pyrene-4-Monoacid-5- dihydrophenanthrene-4- Monoaldehyde carboxylic acid -9,10-Dione 9,10-Dioxo-9,10- Pyrene-4,5-Diacid-9,10- dihydrophenanthrene-4,5- Dione dicarboxylic acid v Contest 1. Introduction 1 1.1. General information about Polynuclear Aromatic Hydrocarbons (PAHs) 1 1.2. Heavy oils, resids, bitumens upgrading 3 1.2.1. General Information 3 1.2.2. Common methods of heavy crudes upgrading 5 1.2.3. Oxidation as a possible pathway in upgrading of “bottom of the barrel” compounds 6 1.3. Chemistry of selective oxidation 8 1.3.1. General Information 8 1.3.2. Ruthenium Ion Catalyzed Oxidation 8 1.3.2.1. RICO in petroleum industry 11 1.3.3. H2O2 used as oxidant 13 1.3.3.1. H2O2 for PAHs degradation 13 1.3.3.2. H2O2 in the combination with H2WO4 17 1.3.4. Molecular oxygen as an oxidant 19 1.3.5. Other oxidation systems 20 1.4. Oxidation of heteroaromatics and metalloporphyrins 21 1.4.1. Sulphur and Nitrogen removal from crude oil 21 1.4.2. Removal of metals from metalloporhyrins 22 1.5. Thesis aims 23 1.6. Thesis overview 24 1.7. References 25 2. Experimental 31 2.1. Introduction 31 2.2. Chemicals used 31 2.3. Preparation of compounds 32 2.3.1. Pyrene-4,5-dione 32 2.3.2. Pyrene-4,5,9,10-tetraone 33 2.4. Preparation of catalyst 33 2.4.1. 1%, 20%WO3/TiO2 33 2.4.2. Ion exchange of polyoxometalates 34 2.4.3. Supported metal catalysts 35 2.4.3.1. Preparation of 5%Ru/TiO2 35 2.4.3.2. Preparation of 2.5% Ru/Co3O4 35 2.4.3.3. Preparation of nano-Ru on hydroxyapatite 36 2.4.3.4. Preparation of Au-Pd catalysts: Sol Immobilisation 36 2.4.3.5. Preparation of Au-Pd catalysts: Modified Impregnation 36 2.5. Reactors and equipment 37 2.5.1. Jacketed reactor 37 2.5.2. Parr autoclave reactor 38 2.5.3. Glass reactor 39 2.6. Description of oxidation procedures 39 2.6.1. Ruthenium Ion Catalyzed Oxidation 39 2.6.1.1. Monophasic solvent system 39 vi 2.6.1.2. Biphasic solvent system 40 2.6.1.3. Porphyrins oxidation using RICO 41 2.6.2. Oxidation using H2WO4 and H2O2 41 2.6.2.1.
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