Pentaerythritol is an important industrial chemical for use in paints and coatings, primarily, but also in fuels, explosives, medicine and polymers. The current process for this material is over 50 years old and is a multi-step process involving 3 homogeneous aldolizations and a crossed Cannizzaro reaction, generating 1.5 tonnes of waste for every 4 tonnes of product. This is also very energy inefficient. We are currently developing a radically different concept, shown below. This will deliver an integrated heterogeneous catalytic process with no waste and a high energy and materials efficiency. Methanol/ Dehydrogenation Base Hydrog Ethanol Catalyst Catalyst Catalyst Pentaerythritol The initial step, CH3OH HCHO + H2, will involve the use of Ag/SiO2 catalysts. This will be in the absence of O2, which differs from the current oxidative dehydrogenation process used to produce HCHO, i.e. a direct dehydrogenation. This step has been optimised by investigation of different surface properties to determine how surface area and dispersion will affect the overall adsorption and consequently the methanol/ethanol conversion and product yields. Deactivation of these catalysts has also been touched on by use of in-situ temperature programmed oxidation’s. Base catalysis involving an aldol type reaction of 2 aldehydes, HCHO and CH3CHO, will give the methylolated aldehyde intermediate. This will then undergo a final hydrogenation to the desired product. Any unreacted aldehydes will, therefore, be hydrogenated back to starting materials and consequently recycled. It will be attempted to couple all three reactions to explore how the catalysts perform when used in succession.

Chapter One reviews the synthesis, properties and reactions of 2-methyleneaziridines, the subject of this thesis. Chapter Two describes the use of these heterocycles in the development of a new four-component synthesis of biologically important α-aminophosphonates. This new chemistry proceeds in moderate to good yield via a “one-pot” process that involves the sequential formation of three new intermolecular bonds and a quaternary carbon centre. This reaction is tolerant to a range of functionalities incorporated in the various components. Deprotection of one of these α-aminophosphonates to the corresponding α-aminophosphonic acid is achieved via a two-step process in very good yield. Chapter Three discusses efforts made towards the development of a multi-component imino Diels-Alder reaction for the generation of 2,3-dihydro-4-pyridones. Initial work suggests acyclic ketimine intermediates are unsuitable for this process. Chapter Four reports unsuccessful attempts made to generate methyleneaziridines bearing electron-withdrawing substituents via in situ N-derivatisation. In Chapter Five, the synthesis of 1,1-disubstituted tetrahydro-β-carbolines from methyleneaziridines is described. The reaction is shown to proceed in moderate to very good yields and a range of β-carbolines were successfully synthesised. High levels of diastereocontrol are demonstrated using a substrate containing a pre-existing stereocentre. Chapter Six details the experimental procedures and characterisation data for the novel compounds produced.

The electronic nose is a device developed to mimic the human olfactory system. Despite raising interest from applications in the field of medicine, quality control, environmental control and security, such devices remain inferior to their biological counterparts. As the biological system is explored further, new discoveries generate new ways of thinking in creating electronic nose devices. This has led to a large variety of sensors and devices, all of which produce data that requires processing. The data are processed to extract information that can be used to classify or quantify the input to the electronic nose. However, as the devices have advanced, the data processing techniques have remained relatively static, refinements of established statistical methods. Recently, investigation into the phenomenon of nasal chromatography has brought about the development of a new class of electronic nose device; the artificial olfactory mucosa. Taking advantage of a retentive effect, inspired by the aqueous mucous layer covering the olfactory epithelium, this new device produces data whose spatio-temporal properties have not been seen in the field of chemical sensing before. Thus there is a need to develop new processing approaches to obtain the information being produced by these new devices. In this thesis, a new processing approach is presented, centred on the use of convolution to produce characteristic signals which contain information arising from a sensor space that is separated both spatially and temporally, realised in the form of multiple sensor arrays separated by retentive columns or channels. This combined signal is then used to extract an information rich feature set that can be passed on to classifiers or quantifiers to make practical use of the data. This method is simulated on data collected during the development of the artificial olfactory mucosa to validate its use, and then applied to several sets of real world data, collected from a variety of devices; from current e-nose technologies to newly developed artificial olfactory mucosa devices. The simulations put the device in very noisy conditions and the processing approach deals well with a high level of noise in most circumstances, its performance only deteriorating in the presence of extremely high levels of sensor drift. However, it is shown that this method not only has validity when dealing with the advanced devices for which it is intended, but also shows an improvement over standard processing approaches when utilised in conjunction with current technologies. Utilising convolution on data collected from current devices, methods are developed where the characteristic signal can be generated internally from a single array, and when applied, produce improvements over standard processing approaches.

Emotion research in sensory and consumer science has gathered significant momentum over recent years and the development of effective emotion measurement methods is a priority in this rapidly growing area. The aim of this research was to advance the use of consumer-led emotion lexicons by using focus groups to increase the efficiency of lexicon generation and by decreasing the number of consumer response categories. In parallel, the ability of the newly generated reduced lexicon to discriminate emotional response across different gender and age groups, and across sensorially distinct beer samples, was evaluated. The new approach was largely effective at discriminating across samples and revealed significant differences in emotional response between genders and between age groups. The reduced lexicon was compared to a full lexicon to ascertain their relative efficacies. Whilst there were differences between the two form lengths, neither was convincingly more effective at sample discrimination than the other, although the full form better differentiated between age groups. The reduced form was also applied to cross-cultural comparisons through the generation of a reduced product-specific consumer-led emotion lexicon in Spain. As in the UK, the approach discriminated well between samples and was able to differentiate between consumer groups. Comparing Spanish and UK responses, ratings of emotions associated with pleasure/pleasantness were similar but there were differences in the use of emotions associated with arousal/engagement/activation. This new methodology was therefore demonstrated to be a valuable tool for investigating cross-cultural emotional response. The approach developed in this thesis provides researchers with an enhanced consumer-led emotion methodology for use with food and beverages. As well as being relatively quick, the approach has been proven to differentiate between products and reveal differences concerning emotional response across different consumer groups and between cultures. These attributes make this emotional measurement approach extremely valuable to this young research area.

With respect to microbiological food safety, beer is thought to be very safe. This is due to the inability of pathogenic organisms to survive in the harsh environment that beer presents, due to low pH, alcohol content and hop acids. However, there are some organisms which have adapted to brewery conditions and can cause off-flavours, hazes or low ethanol yield. The effects of spoilage and subsequent product recall can result in massive economic losses for brewing companies affected. Silver nano particle coatings for pipes and vessels have been suggested as a means of eliminating or reducing contaminants in the brewery. In this study the sensitivity of several brewery contaminants to silver has been investigated. Pichia membranaefaciens, Brettanomyces anomalous, Candida krusei, Hansenula saturnus, Kloeckera apiculata, Rhodotorula mucilaginosa, Saccharomyces ellipsoids var. diastaticus, Lactobacillus brevis, Pediococcus damnosus, were all tested against a range of silver nitrate concentrations (0-1 mM) in YPD, wort and beer. It was found that sensitivity to silver varied between organisms, but no tolerance exceeded 0.55 mM. It was also found that for the majority of organisms, tolerance to silver decreased under simulated brewery conditions i.e. wort, beer and microaerophillic conditions. In the investigation of potential silver tolerance mechanisms, gene microarrays of Saccharomyces ellipsoids var. diastaticus in wort and beer in the presence and absence of silver found that genes most up-regulated during silver stress were those with transmembrane transporter functions. Silver tolerance testing with gene deletion strains of selected potential silver tolerance genes demonstrated reduced silver tolerance for the deletion strains of the HIS1, COX17 and CUP1 genes. All three of these have known functions in copper tolerance. The data collected in this study would suggest that silver (particularily in nanoparticle form) is an effective means of microbial brewery contamination control especially under brewery conditions. However, further study is needed into the effect of silver antimicrobial surfaces on brewery microbial contaminants, silver concentrations needed in antimicrobial surfaces and silver leaching etc.

In this thesis gallic acid-triethylene glycol (GATG) dendrimers were synthesised and efficiently functionalized with hydroxyl groups, phenylboronic acids and primary amines. The interactions of the dendrimers with bacteria and the potential for development of new antimicrobials were evaluated in this study. Specifically, the ability of the dendrimers to induce bacterial clustering and interfere with small molecule autoinducer-2 (AI-2) in the Quorum Sensing (QS) pathway of the marine bacteria V. harveyi was studied with the use of Coulter Counter aggregation assays and detection of QS–controlled luminescence. Novel alkynylated ligands with diol-, tetraol-, glucose- and mannose- moieties were synthesised and successfully functionalized to GATG dendrimers of generation G1 and G3 through catalyst-free azide-alkyne cycloaddition (AAC). The results of luminescence experiments reveled that the dendrimers functionalized with hydroxyl groups decreased AI-2 induced luminescence of V. harveyi MM32 at the at early time points (4 h) while a dose-dependent increase of luminescence and increased bacterial growth was observed at later time points. GATG dendrimers of generation G1 and G3 were decorated with 9 and 81 phenylboronic acid in the periphery. These dendrimers had an inhibitory effect on growth and luminescence as observed by luminescence, aggregation and colony forming unit-counting assays. Although the mechanism is not yet fully understood, these promising results should be further explored. Cationic GATG dendrimers of generation G1, G2 and G3 with 9, 27 and 81 primary amines in the periphery induced formation of clusters in V. harveyi in a generation dependent manner, an improved ability to induce cluster formation when compared with poly(N-[2- (dimethylamino)propyl]methacrylamide), a cationic linear polymer previously shown to cluster bacteria. Viability of the bacteria within the formed clusters and the evaluation of the QS controlled luminescence suggests that the GATG dendrimers may be activating microbial responses by maintaining a high concentration of QS signals inside the clusters while increasing permeability of the microbial outer membrane. Thus, a generation-dependent effect in bacterial luminescence production and membrane permeability was induced by the cationic dendrimers. The inhibition of growth and increased membrane permeability in combination with cell clustering may be promising antibacterial features of these dendrimers. These results highlight the potential of the GATG dendritic platform to develop new antimicrobials aimed to target microbial viability and/or virulence (e.g. adhesion) and encourage further investigations on the importance of polymeric architecture and multivalency in the antimicrobial field.

The large availability of Kraft lignin as an industrial by-product and its polyaromatic characteristic, is ideal to consider the potential for recycling it into fine chemicals. To depolymerise lignin, solvolysis and hydrogenolysis experiments were performed. This research considered whether the low yields of products (fine chemicals) were related to the low content of β-O-4 bonds or if it was also associated to the dissolution of lignin in the solvent solution employed in the reactions. The type of solvents chosen to check the dissolution effect were those with low cost and were more sustainable than traditional solvents. Water, ethanol, isopropanol (IPA) and acetone were used. The water mixtures were applied in the tests in various proportions (25:75, 50:50, 75:25 solvent/water v:v). Due to their ability to break C-C and C-O bonds in lignin model compounds [1][2], the efficiency of platinum and rhodium in these reactions supported on alumina was also studied. It was found that the non-catalysed (solvolysis) and catalysed reactions showed different selectivities but similar overall yields ~ 10 % wt of monomeric phenols. The difficulty in increasing yields was mainly associated with the highly condensed character of Kraft lignin and re-polymerisation issues. To achieve an understanding of Kraft lignin depolymerisation, isotopic labelling reactions were completed in the presence of deuterated solvents as well as deuterium gas. This gave information on how Kraft lignin depolymerises, the influence of solvent to products formation and the involvement of hydrogen in the rate determining steps in the reactions. These results have led to an initial mechanistic understanding on how this complex molecule may yield alky-phenolic compounds. It was revealed that the solvent was directly involved in the products’ formation and that they were not generated by simple thermolysis. In addition, the presence of catalysts and hydrogen influenced product formation. The compounds showed different kinetic isotopic values, suggesting that each of these molecules came from individual mechanisms, highlighting the complexity of their formation. This was a relevant study as most of lignin depolymerisation mechanistic insights are based on model compounds and not on lignin itself. It was of interest to this project to explore not only different catalysts and their relationship to lignin depolymerisation, but also different lignin types. A simple pre-treatment for lignin extraction using sawdust (from oak and birch wood) in a Parr autoclave reactor in the presence of hydrogen, solvent and high temperature was developed. The lignins obtained after the pre-treatment were named parr-lignin and successfully resulted in polyaromatic molecules with less condensed character compared to lignins from Soda or Kraft pulping. Reactions were carried out with these lignins and a sugar-cane lignin. 4 5 Different catalytic systems with these lignins were investigated and how depolymerisation was affected by the metal and support used. The catalysts involved in the reactions included platinum, rhodium, nickel and iron. Various supports such as alumina, zirconia and carbon were tested along with the metals described. It was found that the supports were not inert in these experiments presenting catalytic activity. Materials with low surface area (zirconium catalysts) gave a poor performance compared to the others. In addition, nickel, a non-noble metal, showed as good a catalytic effect in the depolymerisation of these lignins as Pt and Rh. The components in the system influenced the reactions to different extents, especially product distribution. The catalysts had different selectivities and the solvents were not only dissolving lignin but also influencing the results. GPC analysis was performed to give an overview of the condensed level of these lignins and degrees of depolymerisation compared to the original material. GC-MS enabled the identification and quantification of 18 monomeric compounds. The post reaction characterisation of selected alumina catalysts (Pt/Al2O3, Ni/Al2O3 and Al2O3) was performed using XRD, BET, CHN, TPO and Raman Analysis to study the nature of the carbonaceous layer deposited on these materials. The work showed that after reaction the catalysts turned black in colour and the carbon laydown consisted of not only one simple type of carbon, and included graphitic species. The amount of carbon deposited depended on the type of lignin. Oak and birch parr-lignins had the highest and lowest amount of carbon over the catalysts respectively. No obvious trend relating to the type of catalyst, lignin and solvent used to the carbon nature was identified. This work showed that lignins with less condensed nature were less susceptible to solvolysis and more to hydrogenolysis. For example, sugar-cane lignin gave 3.9% of phenolic compounds in the solvolysis while reaction with Rh/Al2O3 gave 12.9% of products. This indicated that more selective cleavage of bonds were promoted by heterogenous catalysts. The results suggested that some compounds were mainly generated via dealkylation and hydrodeoxygenation, allowing a future possibility to generate target molecules. These results were mainly due to the presence of more labile bonds, vulnerable to hydrogenolysis. Highlighting that prior to depolymerisation, the pre-treatment used to extract lignin must be appropriate to avoid depletion of the alkyl-aryl ether bonds (β-O-4 bonds, especially) relevant for fine chemicals generation.

This thesis explores three routes to alleviating the economic barriers to proton exchange membrane fuel cells through reducing, recycling and removing platinum group metals (PGMs). The reduction of PGM content is explored using electrochemistry to assess the novel materials produced when combining fullerene based compounds with electron beam lithography. This technique yields the potential to precisely control the distance between platinum (or other metal) atoms embedded within carbon materials. It is shown that the material alters the onset potential of proton reduction compared to glassy carbon and the methodology for study is developed. The recycling of PGMs is demonstrated by testing the electrochemical behaviour and particle structure of deposited palladium within biomass produced through biohydrometallurgy. Electron microscopy and electrochemistry is used to investigate the biohydrometallurgy process and how the substrate, leachate and reducing agent effect both the particles produced and the electrochemistry observed. Concluding that the un-processed materials may function as future electrocatalysts without further processing steps. The removal of PGM content is investigated, through the electrochemical characterisation of the adsorbed layers and solutions of phosphomolybdic acid, singularly substituted vanadophosphomolybdic acid and doubly substituted vanadophosphomolybdic acid. Describing the complicated multi-electron, multi-step redox chemistry of the potential mediator species, with specific focus on electrode material and the effect of pH.

This PhD thesis presents a modelling and simulation approach for coupling a Solid Oxide Fuel Cell (SOFC) with a Vapour Absorption Refrigeration System (VARS) specifically for refrigerated trucks. Zero dimensional models were developed for the SOFC and VARS and detailed 1D and 3D models were developed for various components of the system. A major challenge in this work was the thermal coupling of two systems working at entirely different temperature levels. The SOFC operates between 700 oC and 800 oC and the VARS between 150 oC and 200 oC. These two systems were successfully coupled to one another using two methods- indirect coupling, using a thermal coupling fluid and direct coupling, using heat pipes. The concept of using heat pipes has been explored for the first time in a desorber and hence that presents the biggest novelty of this work. Design and modelling of all the components in the VARS is a major project in itself hence in this thesis only the desorber of the VARS was designed and modelled. Two different compact desorbers designs were explored. The first one being a plate heat exchanger desorber and the second one a heat pipe integrated desorber. This work is the first one on the combined use of SOFC and VARS for a mobile application. Such a system, if developed, could also have wider implications in areas besides refrigerated transport.

Thermal treatment is the most common method used by industry to ensure food is safe for consumption and to increase its storage life. To ensure safety, food is often overprocessed which can significantly affect its nutritional value as well as taste and flavour attributes. In this study, the heating and mixing efficiency of a bespoke vessel used for heat treatment of complex foodstuffs (250 litre ‘Vesuvio’ vessel manufactured by Giusti Ltd) was investigated. Enzymatic Time Temperature Integrators (TTIs) were used to determine the heat treatment efficiency. TTIs are small unattached measurement devices which contain a thermally labile enzyme: determination of the degree of degradation of the enzyme at the end of the thermal process enables the integrated temperature history to be obtained. TTIs can be used for process validation, particularly when the processing environment is inaccessible for fixed devices such as thermocouples. The reliability and accuracy of the TTIs was determined by exposure to various non isothermal industrially relevant temperature profiles using a Peltier stage and Polymerase Chain Reaction (PCR) device. The integrated temperature histories obtained by the TTIs’ correlated generally well with data obtained from thermocouples installed in parallel, although the error increases with holding time of the heat treatment. The work showed that the TTIs can be used reliably over a range (e.g. Enzymatic TTI made from the α-amylase from the Bacillus Licheniformis can reliably used from 5 to 30 minutes at 85°C) which is relevant for conditions of thermal pasteurisation of interest to this study. The range of time temperature profiles that enzymatic TTIs can monitor depends on the thermal resistance of the enzyme. The heat treatment efficacy of the ‘Vesuvio’ vessel was evaluated using TTIs and two thermocouples fixed onto the vessel wall and impeller shaft at the centre of the vessel. In addition to the plain or ‘free’ TTIs, a new TTI was developed where it was placed at the centre of an open structure to prevent intimate contact between the surface of the TTI and the vessel wall (‘Golf Ball’ and ‘Tie Clip’ TTIs). The food fluid could, however, penetrate the structure. The parameters examined in the study were fluid rheology, fill level (100% and 120% filling level) and the heating options (steam heating via wall jacket or direct injection). The study showed that the thermal process efficiency is lowered as the fluid viscosity increases when the wall jacket was used alone; this was observed by greater differences between the temperatures recorded by the thermocouples between the centre and the vessel wall. This was overcome by using direct steam injection into the vessel contents. Overfilling the vessel was also found to affect performance. The ‘free’ TTIs were found to have a higher thermal treatment than the TTIs which could not directly contact the wall. Under perfect mixing conditions, the ‘free’ TTIs and the TTIs placed inside the open structure should both give close results. However, this is not the case and it can be seen that the discrepancy increases when the mixing conditions worsen (increase of the fluid viscosity, no use of steam injection). The reliability of the TTIs as a validation tool is dependent upon their following the same path as the food fluid, i.e. they should be isokinetic and follow the fluid streamlines. To investigate this issue, the flow of both fluid and TTIs was examined on a reduced scale version of the ‘Vesuvio’ vessel using Particle Image Velocimetry (PIV) and Positron Emission Particle Tracking (PEPT). The effect of changing fluid rheology, agitation speed and filling level were investigated on the basis of a scaling at constant power per unit mass. The PIV experiments showed that the flow was laminar/transitional through bulk of vessel, with significant flow instabilities at the free surface and at the trailing edge of the impeller. Bulk mixing can therefore be expected to occur by laminar mechanisms with some mixing by eddy diffusion present at the free surface. The mixing pattern was not affected by rheology or agitation speed, however, overfilling of the vessel appeared to move the centre of the fluid rotation to above the impeller shaft, as verified using PEPT. PEPT was also applied by inserting either the free tracer into the fluid or placing it within a TTI. Significant differences in the path taken by the TTI and the fluid were observed when the TTI had a significant settling velocity in the fluid. Hence TTIs cannot be assumed to give reliable results in low viscosity fluids (e.g. water).