Large-scale petrochemicals are typically produced using petroleum olefins as a feedstock. The desire to move toward a sustainable and environmentally friendly chemical industry has lead to interest in the use of bio-derived feedstocks such as alcohols which are currently being produced on an increasingly large scale by fermentation or from synthesis gas. The research investigated the direct catalytic production of ethylene, acetaldehyde, ethylene dichloride (EDC), and ethylene oxide (EO) from ethanol. Two approaches were considered: a) the use of a bi-functional catalyst that combines the dehydration capability with ethylene conversion and b) the use of a double catalytic bed system where ethanol was dehydrated over the 1st bed and the product ethylene was converted over the 2nd bed to yield the desired petrochemical product. The dehydration of ethanol was carried out over several zeolites at different operating temperatures, producing mainly ethylene and diethyl ether. The catalytic selective oxidation of ethanol was tested over silver and/or copper compounds supported on several zeolites. The effects of operating conditions, metal loading, and zeolite acidity were determined. High selectivity to acetaldehyde was achieved. Unfortunately, the direct production of EO from ethanol could not be achieved. The catalytic oxychlorination of ethanol was investigated using CuCl2 as the active compound and zeolites were used as either a support or as a pre-bed. EDC was produced via ethylene oxychlorination as well as the oxychlorination and disproportionation of ethyl chloride. The effects of operating conditions and CuCl2 loading were determined. Higher EDC yield was achieved over the dual-bed system compared to the bi-functional catalyst.

Colloidal nanocrystals exhibit interesting and useful size-dependent nanoscale phenomena (e.g. tunable fluorescence in quantum dots and optical absorptions in gold and silver nanoparticles), large surface areas and can be used for a variety of high-tech applications. Care must be taken to produce nanocrystals with well defined size, shape and composition, however, as these parameters directly affect the properties of the colloidal ensemble. Microreactors offer superior control over reaction conditions relative to traditional bulk batch methods and as such offer an attractive route to nanoparticle production. Hence there have been over a hundred papers reporting microfluidic synthesis of nanocrystalline colloids since the first reports in 2002. The work described in this thesis focussed on extending and improving the microfluidic method. Continuous-flow reactors were used initially, however, deposition was found to be a pervading problem with its severity varying with the material being synthesised. To address this problem a new capillary-based droplet-flow reactor was developed in which droplets are generated by the direct injection of confluent reagent streams within a stream of immiscible carrier fluid and, subsequently, can be heated and optically characterised further downstream. The reactor produced stable, controllable droplet flow over a wide range of flow rates, with droplet volumes down to 30 nL, and proved to be highly effective: CdSe quantum dots were synthesised via a high-temperature pyrolytic synthesis with strong control over particle size and size distribution. Crucially, unlike previously reported high temperature droplet reactors, the reactor could be operated indefinitely, without any degradation of the device and minimal variation in the product seen during 24 hours continuous production. To emphasise the versatility and applicability of the droplet reactor, Ag, TiO2 and InP nanocrystals were synthesised (using both organic and aqueous syntheses) and an automatic optimisation routine to reduce size distribution was applied to CdSe quantum dot synthesis.

A new iterative hybrid methodology, incorporating quantum mechanics (QM) calculations and a computationally inexpensive computer-aided molecular design (CAMD) methodology, QM-CAMD, for identification of optimal solvents for reactions is presented. The methodology has been applied to a Menschutkin reaction, where pyridine and phenacyl bromide are the reactants. The QM calculations take on the form of density functional theory calculations with a given solvent treated using continuum solvation models. The accuracy of the solvent QM calculations is assessed by computing free energies of solvation for different solvation models; the IEF-PCM, SM8 and SMD models are studied and SMD is identified as the best model. Rate constants kQM, determined from QM calculations, are calculated based on conventional transition state theory (Eyring 1935, Evans & Polanyi 1935). By using the SMD solvation model and a statistical mechanics derivation of kQM, rate constant predictions within an order of magnitude are achieved. For a small set of solvents investigated by QM, selected solvent properties are predicted using group contribution (GC) methods. 38 structural groups are considered in this approach. The QM-computed rate constants and solvent properties determined by GC are used to obtain a computationally inexpensive reaction model, based on an empirical linear free energy relationship, which is used to predict reaction rate constants. This predictive reaction model is incorporated into an optimisation-based CAMD methodology. With an objective function of maximising the reaction rate constant subject to molecular and reaction condition constraints, optimal solvent candidates are identified. By considering a design space of over 1000 solvent molecules, solvent candidates containing nitro-groups are predicted to be optimal for the Menschutkin reaction. This outcome supports experimental results for a related reaction available in the literature (Lassau & Jungers 1968). For verification purposes, Ganase et al. (2011) have measured (based on 1H NMR data and kinetic analysis) the rate constant for the reaction of interest in a number of solvents and report a significant increase in the rate constant with nitromethane as the solvent.

This Ph.D. study investigates the adsorption of monomeric (isostearic acid, ISA) and oligomeric fatty acids (poly(hydroxystearic acid), PHS 1400 and PHS 3500) to nanoparticles of industrial interest in carriers with different solvent properties. It was found that it was necessary to apply a number of methods to study the adsorption and subsequent stabilisation of the particles by the dispersing molecules, namely adsorption isotherm methods, rheological techniques, atomic force microscopy and UV/vis spectroscopy. The particles (surface) studied consist of uncoated titania and a commercially available titania coated with a combination of alumina and silica. The use of gel permeation chromatography (GPC) to study the adsorption behaviour of polydisperse dispersants provided information not only about the amount of the dispersant adsorbed to the surface, but also the preferential adsorption of low molecular weight components. The displacement of large molecules by smaller ones could be monitored in order to gain insight into the types of adsorption mechanisms at work. It was found that small molecules were unable to fully displace their larger counterparts, suggesting that there was more than one adsorption mechanism in effect. This was supported by the adsorption study of one of the fatty acid dispersants which was esterified with methanol to remove the acid functionality. Adsorption at the particle surface still occurred, but at a much reduced rate. The preferential adsorption of the smaller molecules was also found to be largely eliminated. Adsorption isotherms showed Langmuir-like adsorption behaviour of the molecules to the surface, probably through a combination of acid-base interaction and other specific interactions between surfactant molecule and surface. Adsorption of the dispersant molecules at the particle surface was found to vary with solvent properties reflecting the equilibrium which is established between solubility of the dispersant in solution (χ) and that adsorbed on the surface (г) as a result of adsorption affinity (χs). Steric layer thickness δ could be varied by altering dispersion medium (and hence solvency of the stabilising chain) and by altering molecular weight of the surfactant. This had a significant effect upon the bulk properties of the suspended particles measured by rheological methods. For optimised dispersion performance with high solids load at low viscosity whilst maintaining descrete dispersed particles, as determined by assessing the optical properties of the suspension, the stabilising layer required is dependent upon the particle type and size: small particles require small steric layers. It was found that some degree of polydispersity was important for the oligomeric fatty acid dispersants. Although good adsorption characteristics were observed for the monodisperse monomeric dispersant, adsorption appeared to be optimum for the 1400 Mw oligomeric which had a high proportion of low molecular weight components as well as larger molecules present. Removal of the low molecular weight components from PHS 3500 resulted in interactions measured by AFM that appeared to indicate bridging behaviour due to reduced packing efficiency.

Steam electrolysis using a solid oxide electrolysis cell at elevated temperatures might offer a solution to high electrical energy consumption associated with conventional water electrolysers through a combination of favourable thermodynamics and kinetics. Although the solid oxide electrolysis cell has not. received significant attention over the past several decades and is yet to be commercialised, there has been an increased interest towards such a technology in recent years, aimed at reducing the cost of electrolytic hydrogen. Here, a one-dimensional dynamic model of a planar cathode-supported intermediate temperature solid oxide electrolysis cell stack has' been developed to investigate the potential for hydrogen production using such an electrolyser. Steady state simulations have indicated that the electrical energy consumption of the modelled stack is significantly lower than those of water electrolysers commercially available today. However, the dependence of stack temperature on the operating point has suggested that there is a need for temperature control. Analysis of a possible temperature control strategy by variation of the air flow rate through the stack has shown that the resulting changes in the convective heat transfer between the air flow and stack can alter the stack temperature. Furthermore, simulated transient responses indicated that manipulation of such an air flow rate can reduce stack temperature excursions during dynamic operation, suggesting that the p,oposed control strategy. has a good potential to prevent issues related to the stack temperature fluctuations.

The availability of inorganic membranes which can withstand high temperatures and harsh chemical environments has resulted in a wide range of opportunities for the application of membranes in chemical reactions and separations. In particular, the combination of membrane separation and catalytic reaction into a single operating unit is an attractive way to increase conversions, improve yields and more efficient use of natural resources in many reactions. In this study, asymmetric alumina hollow fibres with different macrostructures consisting of finger-like macrovoids and a sponge-like packed pore structure in varying ratios have been prepared by a combined phase inversion/sintering technique. The asymmetric membranes in hollow fibre geometry possess superior surface area to volume ratios with less gas permeation resistance in comparison to commercial symmetric membranes in tubular and disk configurations. Such asymmetric hollow fibres are used as substrates onto which a Pd membrane is directly deposited by an electroless plating (ELP) technique without any pre-treatment of the substrate surface. A systematic study of the electroless plating of Pd and Ag onto an asymmetric alumina hollow fibre substrate has been carried out by direct measurement of one of the gaseous products, i.e. N2, using gas chromatography (GC). In addition, the influences of the substrate macrostructure on hydrogen permeation through the Pd/Al2O3 composite membranes have been investigated both experimentally and theoretically. Furthermore, a multifunctional Pd/alumina hollow fibre membrane reactor (HFMR) has been developed and employed for the catalytic dehydrogenation of methylcyclohexane (MCH) to toluene (TOL). The developed HFMR consists of a thin and defect-free Pd membrane coated directly onto the outer surface of an asymmetric alumina hollow fibre substrate. 50 wt% Ni/Al2O3 nano-sized catalysts were directly impregnated into the substrate. The performance of HFMR has also been compared with several different reactor configurations.

Propene oxide is an important chemical intermediate in the chemical industry. The propene oxide industry has employed two different types of commercial processes for several decades: the chlorohydrin process and the hydroperoxidation process. However, direct epoxidation of propene with hydrogen peroxide has recently attracted much attention as a more environmentally benign and profitable process. This thesis presents the catalytic reaction engineering of the epoxidation of propene to propene oxide using hydrogen peroxide as the oxidant and titanium silicalite (TS-1) as the catalyst under mild conditions. The kinetics of the heterogeneous catalytic epoxidation was studied in an autoclave reactor using methanol/water mixtures as the solvent. The effects of stirring speed, catalyst loading, reactant concentration, reaction temperature, solvent composition and solvent variation on the propene oxidation are presented and discussed. The catalytic performance of TS-1 impregnated with precious metal nanoparticles such as gold and palladium for the propene epoxidation was also investigated. The influences of the kind of precious metal and treatment process adopted in the catalyst preparation on the propene epoxidation and the hydrogen peroxide decomposition were explored. One of the key objectives of this research was to evaluate a new continuous reactor concept for propene epoxidation and other liquid-phase selective oxidation reactions. A conventional monolith and a confined Taylor flow (CTF) reactor were studied for the propene epoxidation. The influences of gas and liquid flow rates on the hydrodynamics of the structured reactors were investigated under Taylor flow regime at atmospheric pressure. It was found that the variation of hydrodynamics had a significant impact on the production of propene oxide. The effect of operating pressure on the propene oxide production was studied in a pressurised system. In addition, the performances of various structures of reactor column were examined to compare.

Droplet-based microfluidic systems have recently been developed to overcome the problems of slow mixing and dispersion associated with traditional microfluidic systems. By utilising flow instabilities between two immiscible phases, droplets can be generated using normal microfluidic formats. Further, aqueous solutions can be confined and mixed within droplets, resulting in rapid homogenisation and no dispersion. Accordingly, droplet-based microfluidic systems have been utilised in various applications in a high-throughput manner. However, the techniques and methods for droplet formation, manipulation and detection have been continuously studied and improved upon to develop, prepare, manipulate and implement droplet systems for real-world applications. Since droplets can be controllably produced with variable reagent compositions at high generation frequencies (1 kHz or above), on-line detection and characterisation of every high-speed droplet is one of the most important challenges associated with droplet analysis. The ability to extract information from each droplet microreactor is crucial for applications in high-throughput analysis and screening. An appropriate detection technique able to extract the vast amount of information produced in such systems is key in unlocking the full capabilities of droplet-based. In this work, a custom built confocal spectroscopic system was coupled with a droplet-based microfluidic system to conduct high-sensitivity and high-throughput biological experiments. The integration of a confocal system allows for online characterisation of individual droplets in terms of their size, formation frequency, fluorescence intensity and population. The combination of a droplet-based microfluidic system and the confocal detection setup has been successfully used to demonstrate a few high-throughput chemical and biological applications. For example, the droplet system was utilised to demonstrate high-throughput single cell encapsulation, characterisation and quantification for the first time. In addition, highthroughput binding assays and kinetic measurements using a well-known streptavidin-biotin binding model and a protein-protein interaction were performed. Furthermore, a novel approach for fluorescence lifetime imaging (FLIM) was developed and used to analyse mixing patterns within droplets. Specifically, data from FLIM measurements were extracted to determine spatially localised fluorescence lifetimes within droplets and thus a twodimensional map of droplet mixing. Finally, the droplet-based microfluidic approach was exploited to perform biological analysis at the single molecule level.

In recent years ceramic membrane technology has advanced considerably and ceramic membranes are now being applied to a number of high temperature applications, in particular in the energy industry as membrane reactors. Due to the thermal stability of ceramic materials, development in this area is extremely promising as these applications cannot be realized using polymeric membrane technology. Although a wide range of ceramic materials have been developed and processing techniques have improved considerably, the high production cost and lack of control over membrane properties when fabrication processes are scaled up are prohibitive in the commercial application of ceramic membrane technology. However, by using a dry-wet spinning process and the combined phase inversion and sintering technique, novel asymmetric hollow fibre morphologies consisting of a porous sponge-like structure and finger-like macrovoids in which catalyst may be deposited can be prepared in a cost effective way. These asymmetric hollow fibres are prepared from raw materials and are suitable for use in catalytic membrane reactors. Fibre morphology is determined by the rheological properties of the ceramic spinning suspension as well as the parameters used during fibre spinning and the effect of sintering during heat treatment. A generic mechanism has been suggested for the formation of asymmetric structures and the parameters at each of these three stages have been varied systematically in order to predict and control hollow fibre structure. Hollow fibres prepared in this way have been characterized in terms of morphology, pore size distribution, porosity and mechanical strength in terms of their applicability to membrane reactor applications. The versatility of this preparation technique is demonstrated by the inclusion of a chapter describing a catalytic membrane reactor for hydrogen production by water-gas-shift as well as a reactor for the dehydrogenation of propane. It should also be noted that this reactor design could be applied to a number of other catalytic gas phase reactions.

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