Stewart J. Tavener

Green chemistry and the biorefinery: a partnership for a sustainable future

Research into renewable bioresources at York and elsewhere is demonstrating that by applying green chemical technologies to the transformation of typically low value and widely available biomass feedstocks, including wastes, we can build up new environmentally compatible and sustainable chemicals and materials industries for the 21st century. Current research includes the benign extraction of valuable secondary metabolites from agricultural co-products and other low value biomass, the conversion of natures primary metabolites into speciality materials and into bioplatform molecules, as well as the green chemical transformations of those platform molecules. Key drivers for the adoption of biorefinery technologies will come from all stages in the chemical product lifecycle (reducing the use of non-renewable fossil resources, cleaner and safer chemical manufacturing, and legislative and consumer requirements for products), but also from the renewable energy industries (adding value to biofuels through the utilisation of the chemical value of by-products) and the food industries (realising the potential chemical value of wastes at all stages in the food product lifecycle).

Chemistry in Alternative Reaction Media

Preface.Abbreviations and Acronyms.1 Chemistry in Alternative Reaction Media.1.1 Economic and Political Considerations.1.2 Why Do Things Dissolve?1.3 Solvent Properties and Solvent Classification.1.3.1 Density.1.3.2 Mass Transport.1.3.3 Boiling Point, Melting Point and Volatility.1.3.4 Solvents as Heat-Transfer Media.1.3.5 Cohesive Pressure, Internal Pressure, and Solubility Parameter.1.4 Solvent Polarity.1.4.1 Dipole Moment and Dispersive Forces.1.4.2 Dielectric Constant.1.4.3 Electron Pair Donor and Acceptor Numbers.1.4.4 Empirical Polarity Scales.1.4.5 ENT and ET(30) Parameters.1.4.6 Kamlet-Taft Parameters.1.4.7 Hydrogen Bond Donor (HBD) and Hydrogen Bond Acceptor (HBA) Solvents.1.5 The Effect of Solvent Polarity on Chemical Systems.1.5.1 The Effect of Solvent Polarity on Chemical Reactions.1.5.2 The Effect of Solvent Polarity on Equilibria.1.6 W hat is Required from Alternative Solvent Strategies?References.2 Multiphasic Solvent Systems.2.1 An Introduction to Multiphasic Chemistry.2.1.1 The Traditional Biphasic Approach.2.1.2 Temperature Dependent Solvent Systems.2.1.3 Single- to Two-Phase Systems.2.1.4 Multiphasic Systems.2.2 Solvent Combinations.2.2.1 Water.2.2.2 Fluorous Solvents.2.2.3 Ionic Liquids.2.2.4 Supercritical Fluids and Other Solvent Combinations.2.3 Benefits and Problems Associated with Multiphasic Systems.2.3.1 Partially Miscible Liquids.2.4 Kinetics of Homogeneous Reactions.2.4.1 Rate is Independent of Stoichiometry.2.4.2 Rate is Determined by the Probability of Reactants Meeting.2.4.3 Rate is Measured by the Concentration of the Reagents.2.4.4 Catalysed Systems.2.5 Kinetics of Biphasic Reactions.2.5.1 The Concentration of Reactants in Each Phase is Affected by Diffusion.2.5.2 The Concentration of the Reactants and Products in the Reacting Phase is Determined by Their Partition Coefficients.2.5.3 The Partition Coefficients of the Reactants and Products May Alter the Position of the Equilibrium.2.5.4 Effect of Diffusion on Rate.2.5.5 Determining the Rate of a Reaction in a Biphasic System.2.6 Conclusions.References.3 Reactions in Fluorous Media.3.1 Introduction.3.2 Properties of Perfluorinated Solvents.3.3 Designing Molecules for Fluorous Compatibility.3.4 Probing the Effect of Perfluoroalkylation on Ligand Properties.3.5 Partition Coefficients.3.6 Liquid-Liquid Extractions.3.7 Solid Separations.3.8 Conclusions.References.4 Ionic Liquids.4.1 Introduction.4.1.1 The Cations and Anions.4.1.2 Synthesis of Ionic Liquids.4.2 Physical Properties of Ionic Liquids.4.3 Benefits and Problems Associated with Using Ionic Liquids in Synthesis.4.4 Catalyst Design.4.5 Conclusions.References.5 Reactions in Water.5.1 The Structure and Properties of Water.5.1.1 The Structure of Water.5.1.2 Near-Critical Water.5.1.3 The Hydrophobic Effect.5.1.4 The Salt Effect.5.2 The Benefits and Problems Associated with Using Water in Chemical Synthesis.5.3 Organometallic Reactions in Water.5.4 Aqueous Biphasic Catalysis.5.4.1 Ligands for Aqueous-Organic Biphasic Catalysis.5.5 Phase Transfer Catalysis.5.5.1 The Transfer of Nucleophiles into Organic Solvents.5.5.2 Mechanisms of Nucleophilic Substitutions Under Phase Transfer Conditions.5.5.3 The Rates of Phase Transfer Reactions.5.5.4 Using Inorganic Reagents in Organic Reactions.5.6 Organometallic Catalysis under Phase Transfer Conditions.5.7 Triphase Catalysis.5.7.1 Mixing Efficiency in Solid-Liquid Reactions.5.8 Conclusions.References.6 Supercritical Fluids.6.1 Introduction.6.2 Physical Properties.6.3 Local Density Augmentation.6.4 Supercritical Fluids as Replacement Solvents.6.5 Reactor Design.6.6 Spectroscopic Analysis of Supercritical Media.6.6.1 Vibrational Spectroscopy.6.6.2 NMR Spectroscopy.6.7 Reactions in Supercritical Media.6.8 Conclusions.References.7 Diels-Alder Reactions in Alternative Media.7.1 Diels-Alder Reactions in Water.7.2 Diels-Alder Reactions in Perfluorinated Solvents.7.3 Diels-Alder Reactions in Ionic Liquids.7.4 Diels-Alder Reactions in Supercritical Carbon Dioxide.7.5 Conclusions.References.8 Hydrogenation and Hydroformylation Reactions in Alternative Solvents.8.1 Introduction.8.2 Hydrogenation of Simple Alkenes and Arenes.8.2.1 Hydrogenation in Water.8.2.2 Hydrogenation in Ionic Liquids.8.2.3 Hydrogenation in Fluorous Solvents.8.2.4 Hydrogenation in Supercritical Fluids.8.3 Hydroformylation Reactions in Alternative Media.8.3.1 Hydroformylation in Water.8.3.2 Hydroformylation in Ionic Liquids.8.3.3 Hydroformylation in Fluorous Solvents.8.3.4 Hydroformylation in Supercritical Fluids.8.4 Conclusions.References.9 FromAlkanestoCO2: Oxidation in Alternative Reaction Media.9.1 Oxidation of Alkanes.9.2 Oxidation of Alkenes.9.3 Oxidation of Alcohols.9.4 Oxidation of Aldehydes and Ketones.9.5 Destructive Oxidation.9.6 Conclusions.References.10 Carbon-Carbon Bond Formation, Metathesis and Polymerization.10.1 Carbon-Carbon Coupling Reactions.10.1.1 Heck Coupling Reactions.10.1.2 Suzuki Coupling Reactions.10.1.3 Reactions Involving the Formation of C=C Double Bonds.10.2 Metathesis Reactions.10.2.1 Ring Opening Metathesis Polymerization.10.2.2 Ring Closing Metathesis.10.3 Polymerization Reactions in Alternative Reaction Media.10.3.1 Polymerization Reactions in Water.10.3.2 Polymerization Reactions in Supercritical Carbon Dioxide.10.3.3 Polymerization in Fluorous Solvents.10.4 Conclusions.References.11 Alternative Reaction Media in Industrial Processes.11.1 Obstacles and Opportunities for Alternative Media.11.2 Reactor Considerations for Alternative Media.11.2.1 Batch Reactors.11.2.2 Flow Reactors.11.2.3 New Technology Suitable for Multiphasic Reactions.11.3 Industrial Applications of Alternative Solvent Systems.11.3.1 The Development of the First Aqueous-Organic Biphasic Hydroformylation Plant.11.3.2 Other Examples of Processes Using Water as a Solvent.11.3.3 Scale-Up of PTC Systems.11.3.4 Thomas Swan Supercritical Fluid Plant.11.3.5 Other Applications of Supercritical Carbon Dioxide.11.4 Outlook for Fluorous Solvents and Ionic Liquids.11.5 Conclusions.References.Index.

Over one hundred solvates of sulfathiazole

The sulfadrug sulfathiazole forms an extensive family of solvates and adducts, the crystal structures of which show a large variety of hydrogen-bonded frameworks.

Zirconium phosphate supported tungsten oxide solid acid catalysts for the esterification of palmitic acid

A series of zirconium phosphate supported WOx solid acid catalysts with W loadings from 1–25 wt% have been prepared on high surface area zirconium phosphate by a surface grafting method. Catalysts were characterized by N2 adsorption, FTIR, Raman, UV-Vis, 31P MAS NMR, pyridine TPD and X-ray methods. Spectroscopic measurements suggest a Keggin-type structure forms on the surface of zirconium phosphate as a ([triple bond, length as m-dash]ZrOH2+)(ZrPW11O405−) species. All catalysts show high activity in palmitic acid esterification with methanol. These materials can be readily separated from the reaction system for re-use, and are resistant to leaching of the active heteropolyacid, suggesting potential industrial applications in biodiesel synthesis.

Trifluoromethylthiolation of aromatic substrates using thiophosgene—fluoride salt reagents, and formation of byproducts with multi-carbon chains

Reaction of potassium fluoride or tetramethylammonium fluoride with thiophosgene leads to the formation of a nucleophilic source of trifluoromethanethiolate, suitable for the preparation of trifluoromethyl aryl sulfides from activated haloaromatics. Analysis of the by-products in the system demonstrates that complex molecules with up to C4 chains may be formed by the reaction of fluoride salts with thiophosgene.

Can fluorine chemistry be green chemistry

The roles of the element fluorine and its compounds in relationship to green chemistry and clean chemical manufacturing are considered.

The use of Reichardt's dye as an indicator of surface polarity

Reichardts dye can be used to determine the surface characteristics of a range of inorganic and organic materials. This simple, rapid technique gives information regarding the polarity of the surface.

Novel synthetic methodologies for fluorination and perfluoroalkylation

Nucleophilic routes to selectively fluorinated aromatic compounds starting from cheap and readily available nitroaromatics are reviewed. Me3SiCF3, in conjunction with a fluoride, can be used as either a fluorinating or trifluoromethylating agent, and is capable of both the trifluoromethyldenitration and trifluoromethyldecyanation of an aromatic molecule. Nucleophilic trifluoromethylthiolation can be achieved using thiophosgene and a fluoride.

Environmentally Friendly Chemistry Using Supported Reagent Catalysts: Chemically‐Modified Mesoporous Solid Catalysts

Chemically-modified mesoporous materials can be prepared as robust catalysts suitable for application in liquid phase processes such as Friedel-Crafts reactions, selective oxidations, nucleophilic substitutions and aromatic brominations.

The preparation of trifluoromethyl aryl sulfides using KF and thiophosgene

Abstract The trifluoromethanethiolate anion may be generated in situ by the reaction of thiophosgene with potassium fluoride in acetonitrile. This system is used to prepare trifluoromethyl aryl sulfides from activated fluoro- and chloroaromatic substrates via nucleophilic substitution.