Scrutiny over solvent selection in the chemical industry has risen in recent decades, popularising research into neoteric solvent systems such as ionic liquids and supercritical fluids. More recently bio-based solvent products have been considered as replacements for conventional petroleum derived solvents. Because they bear a close resemblance to existing solvent products, bio-based solvents can be readily absorbed into the fine chemical industries. This work develops a methodology for identifying reactions of concern with respect to current solvent selection practice, and then implementing a high performance bio-based solvent substitute. In this thesis, kinetic studies of heteroatom alkylation, amidation, and esterification are documented, and the solvent effect dictating the rate of each reaction ascertained. With the ideal properties for the solvent known, bio-based solvent candidates were screened for suitability in each case study. This process, which employs computational tools, was also applied to model the productivity of the Biginelli reaction as a representative multi-component heterocycle synthesis. A strong case is made for limonene and p-cymene as bio-based solvents for all but heteroatom alkylation from the case studies listed above. Alkylations with nitrogen nucleophiles are instead suited to high polarity solvents, and to this end some bio-based amides were investigated.

Green Chemistry aims to modify chemical processes so that they are more friendly to the environment. The 9th principle of Green Chemistry emphasises the use of catalytic reagents in chemical processes. One way in which ionic liquids can implement this principle is in two-phase catalytic processes. A major drawback of homogenous catalysis processes is associated with the separation of the catalyst from the products. This can be solved by the use of biphasic catalysis, in which the catalyst can be reused several times without any significant changes in its catalytic performance. However, it is vital to understand how catalysts interact with the solvents in a biphasic solvent system. On one hand, it is advantageous to use an ionic form of catalyst (e.g Cu2+) because this improves the retention of the catalyst in the ionic liquid. However, using charged ions affects their catalytic performance, because their coordination characteristics are changed. Many catalysts are transition metal complexes. Therefore, a solvatochromic transition metal is an ideal probe to study the behaviour of ionic liquid, specifically how do the non-coordinating anions in ionic liquids coordinate to metal centres? In this thesis, a set of solvatochromic copper complexes with different charges were synthesised and characterised. The monocationic complexes had the form [Cu(acac)(tmen)]X (acac = acetylacetonate, tmen = tetramethylethylenediamine) where X were Cl⁻, [NO3]⁻, [SCN]⁻, [OTf]⁻, [NTf2]⁻ and [PF6]⁻. The neutral complex was Cu(hfac)2 (hfac = hexafluoroacetonate). A set of non-functionalised ionic liquids and functionalised ionic liquids (FIL) containing hydroxyl, nitrile and ketone groups were also synthesised and characterised. The Kamlet-Taft multi parameter polarity scales were used to study the solvent-solute interactions of the ionic liquids by means of dipolarity/polarizability (π*), hydrogen bond donating ability (α) and hydrogen bond accepting ability (β). The UV-Vis absorption spectra of the complexes were measured in solid state, dichloroethane and ionic liquid solutions. Analysis of these spectra suggested all these weakly coordinating anions coordinate with the copper centre in a different manner depending on the How do Non-coordinating Anions in Ionic Liquids coordinate to Metal Centres coordinating ability of the anion and also the charge of the copper centre. The coordination mode and the order of binding strength for the individual anions were fully studied and analysed. The correlation between νmax and solvent donor number was investigated by measuring UV-vis spectra in a range of molecular solvents, and was used to predict the donor numbers of the ionic liquid solvents. The apparent donor number of ionic liquids was also predicted using the value from the spectra measured in ionic liquids. The effect of functionalised groups in ionic liquids on donor ability has also been investigated by comparing the results from non-functionalied and functionalised ionic liquids.

The selective oxidation of alcohols to the corresponding carbonyl product is an important transformation. Traditionally this reaction has been carried out using stoichiometric oxidants, but such methods are highly undesirable from an environmental viewpoint. In the fine chemical and pharmaceutical industries, oxidative transformations prove problematic, and are often avoided, due to a limited number of existing chemoselective and sustainable oxidation methods. The demand for new, environmentally sustainable and efficient alcohol oxidation methods has driven academic research, and a number of systems have emerged which employ catalytic metal loadings with oxygen as the terminal oxidant. In terms of sustainability, oxygen is the ideal oxidant as it is abundant, and water is the only byproduct formed during aerobic alcohol oxidation catalysis. In spite of the progress made in recent years, the introduction of such systems into industrial processes has not occurred. The aim of this thesis is the development of sustainable and industrially viable catalyst systems for aerobic alcohol oxidation. The research reported in this thesis studies two different catalytic systems. Firstly, the combination of nitroxyl radicals with copper complexes was explored (Chapter 2). The substrate scope was studied, using different nitroxyl radicals, exploring the effect of steric hindrance. The influence of mass transfer and gas pressure was also examined, in order to more efficiently utilise these expensive nitroxyl radicals. In Chapters 3 and 4, research was focused on a zeolite encaged 1,10-phenanthroline-Pd(NO3)2 catalyst system. The aim of these studies was to develop a stable Pd(ll) catalyst which would exhibit longer lifetimes compared to homogeneous systems.

The effects of hydrogen bond formation have been probed in four series of alkylammonium nitrates by increasing the alkyl chain length and by increasing the number of alkyl chains attached with a series of powerful spectroscopic and thermal techniques. Thermal analyses have been used to assess the decomposition temperatures. From thermal analyses it was determined that the majority of alkylammonium nitrates decompose before melting and formed plastic phases, a very important characteristic for fuel cell applications. By using inelastic neutron scattering technique, the entire frequency range from 0 to 4000 cm-1 has been resolved as a result of the absence of the optic selection rules. Hydrogen bonding networks have been studied in the frequency range below 300 cm-1 with inelastic scattering technique accompanied by ab initio and molecular dynamic calculations. The intra-molecular interactions have been asses in the high frequency range by infrared and Raman spectroscopy. By solid-state nuclear magnetic spectroscopy both types of nitrogen moieties have been identified by more than one signal per nucleus which indicates the high complexity of the chemical environment. Crystal structures showed significant strong hydrogen bonds formed between the two ions and a typical layering configuration as in micelle formations. The layered configuration is the consequence of electrostatic, van der Waals and the presence of the extensive hydrogen bond networks. The symmetry of the anion has been lowered and has been assessed through the N-0 in plane bend vibration. Increasing the alkyl chain length above four does not bring any significant differences in the chemical and physical properties. The most significant differences have been observed for the series where there is only one alkyl chain attached leaving three hydrogens available for bonding.

This thesis is about the study of developing novel catalysts and catalytic processes and applying them to convert renewable alcohols produced from biomass into value-added chemicals. It focuses on developing iridium catalysts for hydrogen transfer initiated dehydration of 1,3- propanediol in ionic liquids as solvent and applying functionalized ionic liquids as homo- and heterogeneous catalysts for dehydration of D-sorbitol and rac-1-phenylethanol respectively.

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An emulsion liquid membrane (ELM) containing Cyanex 302 has been successfully used for the recovery of cadmium from synthetic phosphoric acid solutions containing 30% wt. P205. The ELM formulation was optimised for high extraction rate and stability. Cyanex 302, and a mixture of NaC1 (3M) and HC1 (1M), were selected from a set of possible reagents and stripping phases, following equilibrium and kinetic experiments in two-phase systems. Under chemical control the rate of Cd2 extraction was pseudo first order with respect to Cd2 and Cyanex 302 concentration. Arlacel C was found to be the most suitable surfactant for emulsion stability. The dependence of the ELM rate of Cd 2 extraction on the concentrations of cadmium, Cyanex 302, and surfactant, as well as on phase and treat ratio, and homogeniser and stirrer speed, was investigated. Cadmium extraction levels were found to be above 90% for most conditions. The influence of operating variables on emulsion swelling and rupture was also evaluated as a function of time. Swelling of the internal phase of the emulsion reached values greater than 50%, whilst emulsion rupture was below 2%. Emulsion globule size distributions in the stirred tank were measured for different impeller speeds and diameters, reagent concentrations, and emulsion hold-up, using an endoscope attached to a high-speed video camera. A correlation for globule size, accounting for swelling and rupture phenomena, changes in viscosity and hold-up, was proposed and found to be in good agreement with experimental results. This allowed the effect of the stirring speed on the specific interfacial area and the mass transfer coefficient to be decoupled, and led to the conclusion that the overall rate of Cd 2 recovery was controlled by diffusional resistances in the continuous phase. A time- dependent model, and a quasi-steady state model were proposed for the extraction of cadmium with the ELM. Simulations with both models were found to be in good agreement with experimental results.

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