In this thesis, research on kinetic and equilibrium state properties of some new adsorption pairs and non-equilibrium models are investigated. In the first part, the equlilibrium characteristics of adsorption pairs using carbon dioxide as adsorbate are studied. The results showed that the performance of this kind of adsorption system is poor due to the low latent heat of carbon dioxide. New composite ammonia adsorbents, 12.3 wt. % CaCl2/C (3C), 17 wt. % CaCl2/Aluminia (SWS), and 59 wt. % BaCl2/vermiculite, were synthesized and studied. It was found that the modification of host matrices by the salt dramatically increases the ammonia uptake. Hysteresis between the synthesis and decomposition reaction was found and the van't Hoff equation was applied to describe the hysteresis. In the second part, kinetic experiments of the composite ammonia adsorbent, 59 wt. % BaCl2/vermiculite, were performed under isothermal conditions and conditions that would be experienced in a real system. Based on the experimental data, a modified linear driving force (LDF) model is used to simulate the dynamics of adsorption pair. In the model, two resistant constants were obtained empirically from the experimental data. In the third part, the dynamic model of concentration change with heat and mass transfer equation were used to simulate the performance of adsorption system. The results were very encouraging with a maximum COP of around 0.8 and a maximum SCP of around 600W kg-1 in an air conditioning application with one-bed basic cycle. Further studies could focus on the commercial analysis of this promising material in air conditioning. A real lab-scale compact bed could be set up and tested for the performance of adsorption pairs.

The work presented herein focused on the automation of coordination-driven self assembly, exploring methods that allow syntheses to be followed more closely while forming new ligands, as part of the fundamental study of the digitization of chemical synthesis and discovery. Whilst the control and understanding of the principle of pre-organization and self-sorting under non-equilibrium conditions remains a key goal, a clear gap has been identified in the absence of approaches that can permit fast screening and real-time observation of the reaction process under different conditions. A firm emphasis was thus placed on the realization of an autonomous chemical robot, which can not only monitor and manipulate coordination chemistry in real-time, but can also allow the exploration of a large chemical parameter space defined by the ligand building blocks and the metal to coordinate. The self-assembly of imine ligands with copper and nickel cations has been studied in a multi-step approach using a self-built flow system capable of automatically controlling the liquid-handling and collecting data in real-time using a benchtop MS and NMR spectrometer. This study led to the identification of a transient Cu(I) species in situ which allows for the formation of dimeric and trimeric carbonato bridged Cu(II) assemblies. Furthermore, new Ni(II) complexes and more remarkably also a new binuclear Cu(I) complex, which usually requires long and laborious inert conditions, could be isolated. The study was then expanded to the autonomous optimization of the ligand synthesis by enabling feedback control on the chemical system via benchtop NMR. The synthesis of new polydentate ligands has emerged as a result of the study aiming to enhance the complexity of the chemical system to accelerate the discovery of new complexes. This type of ligand consists of 1-pyridinyl-4-imino-1,2,3-triazole units, which can coordinate with different metal salts. The studies to test for the CuAAC synthesis via microwave lead to the discovery of four new Cu complexes, one of them being a coordination polymer obtained from a solvent dependent crystallization technique. With the goal of easier integration into an automated system, copper tubing has been exploited as the chemical reactor for the synthesis of this ligand, as it efficiently enhances the rate of the triazole formation and consequently promotes the formation of the full ligand in high yields within two hours. Lastly, the digitization of coordination-driven self-assembly has been realized for the first time using an in-house autonomous chemical robot, herein named the ‘Finder’. The chemical parameter space to explore was defined by the selection of six variables, which consist of the ligand precursors necessary to form complex ligands (aldehydes, alkineamines and azides), of the metal salt solutions and of other reaction parameters – duration, temperature and reagent volumes. The platform was assembled using rounded bottom flasks, flow syringe pumps, copper tubing, as an active reactor, and in-line analytics – a pH meter probe, a UV-vis flow cell and a benchtop MS. The control over the system was then obtained with an algorithm capable of autonomously focusing the experiments on the most reactive region (by avoiding areas of low interest) of the chemical parameter space to explore. This study led to interesting observations, such as metal exchange phenomena, and also to the autonomous discovery of self assembled structures in solution and solid state – such as 1-pyridinyl-4-imino-1,2,3-triazole based Fe complexes and two helicates based on the same ligand coordination motif.

The aims of this project were to synthesise and characterise a range of inorganic/organic hybrid polymers containing pendant vinyl groups and to study their uses as possible fire retardants. The work consisted of several parallel strands: the synthesis of organically modified silicas; the preparation of vinyl containing silsesquioxanes based on the hydrolysis of cyclohexyltrichlorosilane or propylmethacrylatepolysiloxane; the synthesis of latexes by co-polymerisation of either N-Isopropylacrylamide (NIPAM) or styrene with vinyltrimethoxysilane and the intercalation of styrene or NIPAM into montmorillonite. All samples were characterised using a range of instrumental techniques including infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR), X-ray diffraction (XRD), elemental analysis, thermal analysis, surface area analysis and electrokinetic analysis. Vinyl modified silicas having large surface areas (about 400m2g-1) were successfully obtained. On calcining at 540°C silicas having surface area in excess of 1000m2g-1 were formed. Both the original organically modified silica and a sample after calcining were incorporated into poly(methylmethacrylate) and these samples were compared with pure poly(methymethacrylate) in a cone calorimeter to study their thermal properties. No significant enhancement to the thermal stability of the polymers was observed when the silica was incorporated. Analysis of the co-polymer latexes were inconclusive, in the case of the products obtained from NIPAM but particles having a narrow size distribution were obtained using styrene. There was no apparent trend in the value of the zeta potential with composition. Analysis of the intercalation of monomers into clays and the synthesis of silsesquioxanes were inconclusive.

This thesis describes the preparation and characterisation of environmentally friendly and low-cost nanocrystalline Ni-Co coatings and Co-Ni-P coatings to replace hard chromium coatings for anti-wear and anti-corrosion applications. nanocrystalline Ni–Co coatings with different cobalt contents were electrodeposited.The investigation on the role of tribofilms and wear debris in the tribological behavior sliding against AISI-52100 stainless steel under unlubricated conditions shows that the tribofilms containing iron from the counterparts were formed on the worn surface of the coatings (less than 60 at.% Co), which exhibited high coefficients of friction and wear rates. In contrast, no tribofilm or iron transfer from the pin was found on the Co-rich coatings (more than 70 at.% Co), which exhibited a dramatic friction reduction of 50 % and improved wear resistance. The wear debris contains a mixture of face-centred cubic (fcc) metallic phase and fcc oxidised phase, irrespective of the coating composition. The oxidised debris cannot form an efficient lubricative film to promote separation of the sliding surfaces. Ni-Co coatings exhibited the active-passive polarisation behaviour in 3.5 % NaCl solution. The corrosion resistance of Ni-Co coatings needs to be further improved in order to replace hard chromium for anti-corrosion applications. A new approach to fabricate single-layer Ni-Co coatings with high cobalt content onto mild steel substrates has been developed by optimising of additives (saccharin and 2- butin-1,4-diol (BD)). The present method is more feasible in industry with a competitive cost compared to other techniques, e.g. developing graded coatings and applying pulse current waveforms. The effect of saccharin and BD on the properties of the coatings were investigated, including surface morphology, grain size, crystalline texture, hardness and tribological performance against a steel counterpart. The coating microstrain could be manipulated from tensile to compressive and the fibre texture could be modified from the (10¯10) for hexagonal close-packed (hcp) structure to (0002)hcp / (111)fcc. The inhibition effect of absorbed species on electrodeposited nanocrystalline coatings is explained via grain size and texture analyses. The coating from the bath with an optimised additive content had high hardness (500 HV) due to its reduced grain size (11±2 nm) and improved tribological properties due to the high proportion of hcp structure. The Hall-Petch relationship can fail when the grain size is below a critical value of tens of nanometres. This occurs particularly for coatings having porous surfaces. In this study, electrodeposited nanostructured Ni-Co coatings with different porosities were obtained by controlling the concentration of nickel sulphate and nickel chloride within electroplating baths. The coatings with the grain size in the range of 11-23 nm had varying surface morphologies and different porosities. A cluster-pore mixture model has been proposed by considering no contribution from pores to the hardness. As the porosity effect is taken into consideration, the calculated pore-free hardness is in agreement with the ordinary Hall-Petch relationship even when the grain size is reduced to 11 nm for the Ni-Co coatings with 77±2 at% cobalt. The present model has been applied to other porous nanocrystalline coatings, and the Hall-Petch relationship is maintained. In order to further improve the microhardness, wear resistance and corrosion resistance of Ni-Co coatings to match the properties of hard chromium, a new Co-Ni-P coating has been developed by combining the precipitation hardening of Ni-P alloys with the lubricity of cobalt-rich Ni-Co coatings. The evolution of composition and microstructure, hardness, thermal stability and tribological properties have been investigated. The local pH near the cathode played an important role in the change of the microstructure from nanocrystalline to amorphous along the growth direction as the phosphorus content increased from 7 at.% to 26 at.%. The highest microhardness (980 HV) and the lowest wear rate (an order of magnitude lower than that of hard chrome coatings under the same dry sliding conditions) were achieved by annealing the coatings at 400 °C facilitating precipitation hardening. Furthermore, the coefficients of friction of both the as-deposited Co-Ni-P coating and the heat-treated samples were approximately 0.3, only half of that of hard chrome coatings. The roll-like debris found on the worn surfaces of the coating annealed at 500 °C were oriented perpendicularly to the sliding direction. The Co-Ni-P coating annealed at 400 °C exhibited improved anti-corrosion properties, which can be attributed to the formation of a protective oxide layer.

The major aim of this project was development of novel covalently modified glassy carbon electrodes for application in NADH-dependent biosensors using combinatorial and high-throughput methods. Studies on transition metal complexes containing redox active 1,1-phenanthroline-5,6-dione (phendione) ligand(s) showed they are effective electrocatalysts for oxidation of NADH. In order to covalently tether the metal complexes at the GC surface, the design of GC electrodes modified with novel metal complexes bearing phendione ligand(s) was proposed based on sequential electrochemical and solid-phase synthesis methods. Initial work involved optimisation of the process for modification of individual GC electrodes. Firstly, following earlier work, the GC electrodes were electrochemically functionalised by primary amines or a diazonium salt bearing Boc-protected amine groups, which allowed introduction of chelating ligands at the GC surface under solid-phase coupling conditions. The final step involved coordination of the bidentate ligand at the GC surface to the metal centre and formation of novel metal complexes under solid-phase coupling conditions. The successfully modified individual electrodes were applied in the design of a library of GC electrodes modified with different linkers, ligands and metal complexes and prepared in a combinatorial and parallel way. The library was electrochemically screened in a high-throughput way using a multichannel potentiostat, which allowed instant comparison of electrochemical and electrocatalytic properties between different members of the library. The experimental data extracted from HTP screening of the library were used for evaluation of a) the surface coverage obtained for different library members; b) the catalytic activity towards NADH oxidation and c) the kinetics parameters kcat and KM for the electrocatalytic oxidation of NADH for all members of the library.

Current questions concerning the safety of industrial chemicals requires that many substances be re-evaluated to quantify the significance of their environmental and occupational hazards. A large number of epoxides have been found mutagenic and carcinogenic. However, for many of these epoxides the stereochemical requirements are still undefined. After a general introduction into the toxicology of epoxides (Chapter 1), Chapter 2 reviews the general methods developed, and adopted in the syntheses of chiral epoxides and their precursors. In Chapter 3, the materials, methods and instruments used in this project are outlined. A new synthetic route to optically active epoxides is described in Chapter 4. The acid catalysed ketalisation of D-camphorquinone with racemic 1,2-diols is shown to afford a kinetic resolution from which one diastereoisomer is formed predominantly. This dioxolane was hydrolysed to yield an optically active diol or converted into an epoxide. A general route to chiral 1,2-diols is described. The reaction of the enantiomers of methyloxirane with biological nucleophiles (protected N-acetyl esters of amino-acids containing reactive nitrogens [ histidine imidazole nitrogens ] or sulphur [ cysteine ] and the amino ester of valine) is described in Chapter 5. This chapter determines the structure and stereochemistry of the products, along with enantio- selectivities and kinetic data. This data was used to ascertain the relative rates of nucleophilic attack upon the enantiomeric pairs. For ambifunctional nucleophiles identification of the preferred site of alkylation and the regioselectivity of nucleophilic attack was deduced. A method for deducing the enantioselectivity of nucleophilic groups in peptides using specifically deuterated epoxide racemates is described (Chapter 6). Product mixtures are determined by m.s. The use of this method to deduce enantioselectivities in peptides and proteins is outlined.

Poly(3-nitratomethyl-3-methyloxetane) (PNMMO) is a nitrate ester pre-polymer which can be cured with an isocyanate and utilised as a binder in solid rocket propellants; CH3 X[-H2C-C-CH2-0-]nY CH2ONO2 where X and Y are the end groups. Electrospray ionisation (ESI) mass spectra of untreated PNMMO show that it contains a series of low-mass cyclic and linear oligomers incorporating up to 22 monomer units. Oligomers of higher mass appear not to be detectable by ESI mass spectrometry. The relative abundances of the cyclic oligomer ions in the spectra are affected by various factors but the governing influence is the size of the alkali metal cation used to promote ionisation. The cyclic and linear oligomers can be separated from each other using column chromatography and the cyclic species can be individually characterised by ESI, size- exclusion chromatography (SEC) and 13C nuclear magnetic resonance (NMR) spectroscopy. Thermal degradation results in the gradual increase in intensity of two main new absorptions around 1729 and 1550 cm'1 in the solution infrared (IR) spectrum of PNMMO. The band at 1729 cm 1 is attributed to the carbonyl group in a formate ester and the formate proton and carbonyl carbon associated with this compound are clearly visible in the ‘H and l3C NMR spectrum at 8.1 and 162 ppm respectively and can be cross-correlated by 2-D NMR. The absorption at 1550 cm 1 is attributed to the asymmetric stretch of a nitro group attached to a tertiary carbon. We propose that this nitro species is formed by the recombination of NO2 following the loss of N02 and subsequent elimination of CH20 from the PNMMO side-chains. The assignment of this nitroalkane was confirmed by ESI and spectroscopic characterisation of a nearly pure sample of the tetrameric nitro species isolated from pyrolysed PNMMO using column chromatography. The thermal degradation pathways and products of polypropylene oxide) (PPO) were found to bear some similarities to those of PNMMO. ESI and matrix-assisted laser desorption ionisation (MALDI) mass spectra of thermally and photolytically degraded PPO show that oxidation occurs predominantly at the secondary carbon as opposed to the tertiary carbon.

This thesis describes various applications of high field n.m.r. for the elucidation of coal structure, and concentrates on discovering the chemical environments of the heteroatoms in coal i.e. those elements other than carbon and hydrogen. Chapter 2 describes how hydroxyl groups may be converted to trimethyl siloxyl groups, observation of which by 29si n.m.r. allows one to determine the types of hydroxyl functionalities present in the original material. Such derivatization methods are well known. However trimethyl siloxyl groups give 29si resonances that have predictable chemical shifts and so the derivative spectra of complex coal tars and extracts are easy to interpret. Using this technique we have investigated the nature of hydroxyl groups in a rank series of coal tars. This has given us some insight into the way the hydroxyls are affected by coalification. Chapter 3 is a demonstration of the use of n.m.r. as a detector for H.P.L.C. This has two principle novelties over previous work. Firstly it does not involve building a special probe and secondly, the data is presented as a contour plot of intensity vs. retention time and chemical shift. This method has been used to investigate the nature of several tar fractions and complements the derivatization technique of chapter 2. The final chapter shows how the nature of sodium in coal was determined by 23Na MAS-NMR. By using the information contained in the chemical shift and linewidths of raw and dried coal it was concluded that sodium exists bound to the surface of coal pores by oxygen functions such as carboxylates and phenoxides. It does not exist as sodium chloride microcrystals as once thought.

No description available.

The work presented in this thesis reports the development of a non-stick coating for bakeware from renewable materials. Also investigated is the use of epoxidised vegetable oils for renewable polyesters and nanocomposites. Chapter 1 provides a brief introduction to materials from renewable sources leading to a more detailed overview of triglyceride chemistry and finishes with a brief background of non-stick coatings. Chapter 2 presents the development of the non-stick coating. Current commercial coatings were analysed identifying the key components that could be replaced with more environmentally friendly alternatives. Thermal and photo-initiated curing regimes were studied on a range of epoxidised vegetable oil monomers for use as a polymer binder. Thermally cured epoxy soybean oil using a sulfonic acid catalyst was deemed superior. Additives to this resin such as silica, pigments and solvents were investigated to produce a coating formulation which was analysed by TGA and industry standard surface tests including pencil hardness, flexibility and cross-hatching. Chapter 3 reports the hydrosilylation reaction on vegetable oils. A model system with fatty acids and triethylsilane was proposed which lead to the formation of crosslinked silicone rubbers using di- and polyfunctional silanes and vegetable triglycerides. Epoxy fatty acid – silicone hybrids were used as release agents in the non-stick coating formulation described above. Chapter 4 focuses on the ring opening polymerisation of epoxidised vegetable oils with cyclic anhydrides forming crosslinked polyesters. Mechanical properties such as tensile strength, elasticity and Young’s modulus were measured as well as thermal analysis (TGA, DSC and DMTA). It was found that the physical properties were related to the crosslinking density with a higher density lead to strong but brittle polymers whereas lower crosslinking density samples were soft and elastic. The crosslinking density could be controlled by the choice of the vegetable oil type, anhydride type and the epoxide : anhydride ratio. Chapter 5 uses these polyester resins in the formation of nanocomposites. Nanocomposites were created using hollow silica shells and polyaromatic hydrocarbons and the mechanical properties measured and compared to the vegetable oils resins alone and other work in this area. This was followed by the copolymerisation of epoxy vegetable oils and styrene oxide and blends of grapessed and euphorbia oils with different epoxide functionality. It was found that blends could achieve properties of both oils such as high strength and elasticity in the same polymer sample. Chapter 6 describes the experimental procedures and chemical analysis of reactions performed in this thesis.