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A general approach to the synthesis of densely functionalised cyclopentenols was developed to circumvent selectivity and functionalization issues often encountered when attempting to access these synthetic intermediates using the methods currently in use. A range existing reactions were expanded upon, culminating in the formation of allyl silane starting materials for an intramolecular Sakurai reaction. The protocol was adapted to grant access to 'three of the four possible diastereoisomers of the cyclopentenol product. Conditions for a combined Claisen-Sakurai reaction were established. Treatment of diaryl ethers under basic conditions was found to lead to selective formation of either the 2- or 3- allylated ketone. Exhaustive mechanistic studies led to the proposal of base mediated isomerisation-Claisen and [2,3]-Wittig-anionic oxy-Cope rearrang~ment cascade sequences

Observations of atmospheric gas concentrations are very useful in the study of globally important ecosystems. Past observational efforts, however, have been focused on atmospheric measurements of ‘background air’, leaving the continental interiors under-represented. I present results from pilot, multi-species, atmospheric measurement campaigns in the Hainich Forest, Germany in 2005, and I describe the development, deployment, and results from high-precision continuous atmospheric measurements of CO2, O2, CH4, CO and N2O at the Zotino Tall Tower Observatory (ZOTTO) in the boreal forest of central Siberia from November 2005 to June 2007. Atmospheric variations were studied on seasonal, synoptic and diurnal time scales. Among the interesting features of the ZOTTO record are: 1) CO2 and O2 seasonal amplitudes of 26.6 ppm and 190 per meg (equivalent to 39.8 ppm in CO2); 2) a west-east gradient of –7 ppm of CO2 (in July 2006) between Shetland Islands (Scotland) and ZOTTO that reflects summertime continental CO2 uptake; 3) attenuation of the oceanic component of the O2 seasonal amplitude (Atmospheric Potential Oxygen; APO) at ZOTTO resulting in an amplitude of 45 per meg compared to 56 per meg observed at Shetlands; 4) high fire emissions of CH4 and CO in summertime with the minima of their monthly averages similar to seasonal cycles of these gases in the marine boundary layer; 5) large vertical gradients in CO2, CH4 and CO during ‘cold events’ (air temperatures below -30°C), suggesting separated layers of air and local sources possibly combined with other effects; 6) lower CO/CO2 ratios (1-4 ppb/ppm) from fossil fuel burning compared to those measured in Europe, with large CH4 contributions; 7) diurnal vertical CO2 gradients in spring 2007 giving estimates of night-time respiration fluxes of 0.04±0.02 mol C m-2 d-1. A comparison with REgional MOdel (REMO) simulations showed discrepancies in daily averages of CO2 attributed to errors in the model’s vertical mixing and prescribed terrestrial fluxes. Nevertheless, REMO exhibited good agreement in meteorological variables (compared to weather stations close to ZOTTO) and seasonal cycles of CO2, APO and CO. Studies of fire events showed high emission ratios of CO/CO2 and CH4/CO2, comparable with those reported for similar ecosystems, and in relatively good agreement with the model estimates.

As with many bioprocesses, the acetone-butanol-ethanol (ABE) fermentation faces a number of economic drawbacks when compared to the petrochemical route for butanol production. In the 1920s biobutanol was the second largest biotechnology industry, after bioethanol production. However it became difficult to compete against the petrochemical route for reasons including the low product butanol concentration, because of product inhibition resulted in low butanol productivity and due to slow fermentation and low ABE yields. These lead to uneconomical butanol recovery by the conventional method, distillation, due to the high degree of dilution. Recent interest in biobutanol as a biofuel has led to re-examination of ABE fermentation with the aim of improving solvent yield, volumetric productivity and final solvent concentration to reduce the cost of production and thereby produce biobutanol that is cost-competitive with the chemical synthesis butanol. ABE fermentations were carried out in an intensified plug flow reactor known as the batch oscillatory baffled bioreactor (BOBB). The “BOBB”s were designed and built for this project. The effect of oscillatory flow mixing on ABE fermentation was compared to that of conventional stirred tank reactors (STRs) at power densities in the range 0 to 1.14 Wm⁻³. The maximum butanol concentration in this range in a BOBB was 34% higher than the STR. Some increase in butanol productivity was also observed: 0.13 gL⁻¹h⁻¹ in BOBBs, compared to 0.11 gL⁻¹h⁻¹ in the STRs. It can be concluded that at similar power densities, BOBB fermentation shifts to solventogenesis earlier than in STRs, resulting in higher solvent productivity. It is hypothesised that the reason for early solventogenesis in the BOBB was the higher solvent-producing cell concentration, due to the more uniform shear field in the BOBB, so the cell would be less exposed to high shear thereby reducing the risk of cell lysis. Two-stage ABE fermentations in BOBB increased the butanol productivity by up to 37.5% over the one-stage fermentation. Butanol productivity was further increased by 97% when gas stripping was integrated to the two-stage ABE fermentation. While the one-stage fermentation integrated with gas stripping increased the butanol productivity by 69% to 0.12 gL⁻¹h⁻¹ (as opposed to 0.071 gL⁻¹h⁻¹ in a similar fermentation without gas stripping). A simple model to describe the one-stage at oscillatory Reynolds number (Re₀) 0 and 938, and the two-stage ABE fermentation in BOBB II was developed. The model summarizes the physiological aspects of growth and metabolite synthesis by Clostridium GBL1082. The prediction of the models were in good agreement with experimental results incorporating mixing (Re₀938) and moderately agreed with results from Re₀0 and the two-stage fermentation.

Whilst substantial empirical experimental investigation is available in the literature on amorphous Boron phosphide (BP) coatings, there is not much information about the scienti¯c properties exhibited by this material in var- ious applications such as in infra-red imaging systems. Also a great deal of the industrial application of amorphous BP coatings is in the area of infra- red imaging systems. This thesis is based on an attempt to understand the underpinning scienti¯c basis for the properties of amorphous Boron phos- phide coatings, using a range of surface, chemical, physical, electrochemical, computational (quantum mechanics) and mechanical characterisation tools. The results of this investigation has not only helped in unveiling the scien- ti¯c basis of some of the current empirically derived properties of amorphous BP coatings, used in the infra-red imaging industry, but has con¯rmed that amorphous BP is a potential coating for engineering substrates used in var- ious industries if the PECVD deposition process is optimised. This inves- tigation also establishes the link between the properties of amorphous BP coatings and the bonds in the different stoichiometric composition of the coatings.

This thesis presents a systematic approach for the synthesis of reaction-separation-recycle flowsheets including ternary heterogeneous azeotropic mixtures. The methodology incorporates three main components. Firstly, a shortcut distillation model for heterogeneous azeotropic distillation columns is developed. Secondly, a synthesis methodology is proposed for generating, evaluating and screening separation flowsheet alternatives. Finally, the separation flowsheet synthesis methodology is systematically integrated with an existing reactor network design methodology to generate feasible and cost-effective reaction-separation-recycle flowsheets. Heterogeneous azeotropic distillation systems include distillation and decanting operations. Columns with stand-alone decanters and with integrated decanters are considered for separation. A shortcut distillation model is proposed, based on Underwood's method, which is modified to calculate the minimum reflux ratio in ternary heterogeneous distillation columns for direct and indirect splits. The new model requires determination of the controlling fixed point for a given type of split. Case studies demonstrate the applicability of the model for various ternary heterogeneous azeotropic systems. The minimum reflux requirements predicted by the model are in good agreement with those of the more rigorous boundary value method results using commercial software DISTIL and rigorous simulation results using HYSYS. A systematic procedure for synthesising and screening economically promising distillation sequences separating ternary heterogeneous azeotropic mixtures is proposed. The algorithm of Tao et al. (2003) to generate high-purity separation alternatives using distillation and stand-alone decanters is extended to include integrated distillation-decanting configurations. High recoveries of these high-purity products are obtained by recycling non-product streams to suitable destinations within the flowsheet. The recycle destination selection heuristics proposed by Tao et al. (2003) are extended to eliminate uneconomical alternatives. The minimum vapour load of the sequence calculated using the new shortcut model is used as a cost indicator to evaluate and screen separation alternatives. Case studies illustrate the applicability of the synthesis approach and show advantages to integrating distillation and decanting within the separation sequence. A systematic methodology is proposed for synthesising feasible and economically attractive reaction-separation-recycle flowsheets including ternary heterogeneous azeotropic mixtures. Using the separation flowsheet synthesis procedure, flowsheet alternatives are generated and evaluated for separation feed compositions lying in various regions of the ternary composition space. These separation flowsheets are used to construct cost functions in terms of the feed conditions, such as flow rates and compositions. The cost functions are applied within an optimisation framework to explore reaction-separation trade-offs. The reaction-separation-recycle synthesis problem is formulated mathematically with continuous and discrete variables. Economically attractive flowsheets are synthesised by optimisation, using the stochastic optimisation technique of simulated annealing. Two industrially important case studies, vinyl acetate and di-isopropyl ether production, demonstrate the applicability of the proposed approach.

This thesis investigates and conveys the versatility and range of applications for Task-Specific Ionic Liquids (TSILs). A number of iron-based TSILs were prepared and their applications in the field of electrochemistry were studied using Cyclic Voltammetry (CV). Trihexyl(tetradecyl)phosphonium ferricyanide and trihexyl(tetradecyl)phosphonium ferrocyanide were prepared and characterised. Their rheological and electrochemical properties were investigated before the effectiveness of these TSILs in the phase separation of mixed aqueous-organic solvent solutions was briefly assessed. Given that ferro/ferricyanides are widely known to be effective in bioelectrochemistry as mediators for the oxidation of glucose by glucdse oxidase, the mediation ability of these . iron-based/phosphonium TSILs in this enzymatic reaction was stud)ed. The bioelectrochemical application of a ferrocene TSIL, 1-(ferrocenylhexyl)-3-methylimidazolium bis (trifluoromethanesulfonyl)imide, was also investigated. Successful mediation was confirmed and therefore, 1-(ferrocenylhexyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)imide was studied further as a mediator in Dye Sensitised Solar Cells (DSSCs).

No description available.

The main objective of this work was to study the sensitivity of the Heterogeneity Analysis surface characterisation methods in the detection of the surface modification of barium sulphate due to the presence of various amounts of preadsorbed sodium tripolyphosphate (STPP). The main method considered was HILDA (1974) and three isotherms were also analysed using CAEDKON (1975). A series of adsorbates: krypton, argon, nitrogen and carbon monoxide were used to probe the surface of barium sulphate. Precipitated barium sulphate was prepared and solution adsorption isotherms of STPP were determined at pH 7.6 and pH 9.0. The barium sulphate samples were characterised by the following techniques: x-ray diffraction, electron spectroscopy for chemical analysis and scanning electron microscopy. A grease and mercury-free volumetric adsorption apparatus was employed which consisted of four pressure gauges ranging from 10-5 to 103 mmHg. All the adsorption measurements were determined with great accuracy and detail at 77.SK. Isosteric heats were estimated from nitrogen adsorption isotherms at 77.S, SO.S and Sl.6K on barium sulphate. The Heterogeneity Analysis was used to analyse the nitrogen and carbon monoxide data for the preadsorbed samples, which showed the high energy sites present on the surface of barium sulphate were reduced considerably by adsorbing STPP. Furthermore, within the HILDA method, the Langmuir, Hill-de Boer and Fowler-Guggenheim models were compared, methods of termination of the data was investigated, and the stability of results was studied. A normalisation procedure for submonolayer data was applied. The specific surface area of the samples used were estimated and compared with various adsorbates, different batches of barium sulphate and increasing coverage of STPP.

Chapter 1 reviews the literature on the structures and properties of inorganic framework materials that are of relevance to this thesis. In particular the phenomenon of negative thermal expansion and the AM(_2)O(_8)/AM(_2)O(_7) families of materials are discussed. Chapter 2 describes the methods of synthesis and characterisation of the materials investigated in this thesis. Chapter 3 discusses the dehydration reaction of M(_o)O(_2).H(_2)O.PO(_3)OH. The study involved the introduction of a new methodology for whole pattern powder fitting; this method was later verified by full Rietveld analysis. This investigation led to the discovery and structure solution of two new molybdenum phosphates using powder XRD. These materials have been named β-(MoO(_2))(_2)P(_2)0(_7) and β -(Mo0(_2))(_2)P(_2)0(_7). A structural pathway for the dehydration reactions has been proposed which is consistent with all of these structures and other analytical data obtained. Chapter 4 describes investigations into the structures of a-(Mo02)2P207 by powder diffraction and NMR methods. The high temperature structure was confirmed to be related to a literature model. The low temperature structure was further studied by electron diffraction, second harmonic generation and solid state NMR. The use of these complementary techniques with powder X-ray and neutron diffraction data, led to the solution of the complex superstructure. Chapter 5 describes a study into the structures of (MoO)(_2)P(_4)0(_13). The material undergoes a phase transition at 523 K. The low temperature structure contains 441 unique atoms and as such is the most crystallographically complex oxide solved to date. The high temperature structure contains 253 unique atoms and is the second most complex oxide in the ICSD. Chapter 6 describes the in-situ X-ray studies on the synthesis of M0P(_2)O(_7) from precursors Mo0(_2)(P0(_3))(_2) and (MoO)(_2)P(_4)0(_13) in an H(_2) environment. (Mo0(_2))(_2)P(_2)0(_7) was studied under similar conditions and found to decompose to an unidentifiable poorly crystalline phase. Chapter 7 describes the discovery of a new high temperature synthetic route to cubic ZrMo(_2)0(_8) using extremely rapid time-resolved XRD data recorded at the ESRF. The cubic material forms from its constituent oxides at 1350 K and can be isolated back at room temperature using a quench cooling method. A pure phase sample can be prepared using a Zr0(_2):Mo0(_3) ratio of 1:3. The entire synthesis occurs within seconds and precise control of temperature and time is crucial for this synthesis.