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Full-Text Articles in Chemistry

Metal Coordination And Cis-Trans Isomerisation Of Benzene Dihydrodiols, Catriona O'Meara Apr 2008

Metal Coordination And Cis-Trans Isomerisation Of Benzene Dihydrodiols, Catriona O'Meara

Masters

Abstract In this thesis, a viable route for conversion of arene cis-dihydrodiols to their trans isomers was investigated. The cis-dihydrodiols can be produced by large scale fermentation but their trans analogues are not accessible using this approach. The trans dihydrodiols are potentially important chiral building blocks in synthetic chemistry particularly because they have the advantage that they are more stable than the cis-isomers. The principal aim of this work was to carry out parallel studies to inform the development of the synthetic pathway under study by; (a) synthesis of organometallic and organic intermediates and products and, (b) investigation of the …


Matrix Effects, Development Of Clean-Up And Lc-Techniques Contributing Towards A Reference Lcms Method For The Analysis Of Lipophilic Marine Toxins, Mairead Anne Mcelhinney Jan 2007

Matrix Effects, Development Of Clean-Up And Lc-Techniques Contributing Towards A Reference Lcms Method For The Analysis Of Lipophilic Marine Toxins, Mairead Anne Mcelhinney

Masters

The most widely used reference method in Europe for the detection and monitoring of lipophilic marine toxins is the Mouse Bioassay (MBA) as first described by Yasumoto et al., (1978). The MBA offers a good level of protection to human health and is capable of detecting the overall toxicity of previously known toxins. However, there are drawbacks associated with the use of the MBA as it is both expensive and time consuming and can give false positives due to interferences (Suzuki et al, 1976). The problems associated with the original mouse bioassay have led to several modifications (Yasumoto et al, …


The Synthesis Of Zinc Oxide By Direct And Indirect Methods, Grainne Duffy Jul 2006

The Synthesis Of Zinc Oxide By Direct And Indirect Methods, Grainne Duffy

Masters

The synthesis of zinc oxide through three routes was investigated; carboxylic acid chelation, polymer assisted synthesis in an alcoholic medium and slow thermolysis of precursor. In the case of carboxylic acid chelation, it was determined that the rate at which the precursor is formed has a significant effect on the quality of zinc oxide particles produced. Investigation of the effect of concentration, pH and species of chelating agent used on the purity and structure of product was undertaken. Examination of the composition and morphology of materials produced revealed the presence of single-crystalline spheres, the packing density and aggregation morphology of …


The Determination Of Environmentally Important Metals In Marine Sediments, Linda Tyrrell Jan 2005

The Determination Of Environmentally Important Metals In Marine Sediments, Linda Tyrrell

Masters

Surface sediment samples were collected at sites within the Rockall Through at water depth ranges from 700 – 2774 metres. The study area was predefined by the availability of samples. Samples were collected by the British Geological Survey during their gravity core survey undertaken in 1998. Methods were optimised and validated for lead, cadmium, chromium, copper, nickel, zinc, lithium and aluminium using atomic absorption spectroscopy following total digestion, and for mercury, using cold vapour atomic fluorescence spectroscopy following partial digestion. The measured metal concentration were normalised to Li to compensate for the influence of natural variability in the concentration of …


Atmospheric Chemistry Of Aromatic Compounds, Bernadette Duffy May 2002

Atmospheric Chemistry Of Aromatic Compounds, Bernadette Duffy

Masters

Rate constants (in units of 10-11 cm3 molecule-1s-1) were measured for the following reactions at 298+-2K and 1 atmosphere pressure using a relative rate technique. k(OH+Benzene)= 1.42+-0.1; k(OH+p-Xylene)= 15.9 +-2.5 k(OH+Toluene)=6.30+-0.15; k(OH+o-Ethyltoluene)=14.1+-1.1; k(OH+Ethylbenzene)=7.50+-0.72:k(OH+m-Ethyltoluene)=23.0+-1.5; k(OH+o-Xylene)=14.5+-3.1; k(OH+p-Ethyltoluene)=14.2+-1.0; k(OH+m-Xylene=23.1+-2.2: k(OH+1,3,5-Rimethylbenzene= 69.7+-4.3 The increase in reactivity with increasing degree of alkyl substitution on the aromatic ring supports the conclusions of previous studies that the dominant reaction pathway at room temperature for reaction of hydroxyl radicals with aromatic compounds is addition to the benzene rig. The rate data are compared with previous measurements and discusses in terms of structure-activity relationships The Photochemical Ozone Creation Potentials …


Kinetic Studies On The Reaction Of Hydroxyl Radicals With Aromatic Compounds, Paul Chadwick Aug 2000

Kinetic Studies On The Reaction Of Hydroxyl Radicals With Aromatic Compounds, Paul Chadwick

Masters

No abstract provided


Synthesis Of Fluroxypyr For The Use On Broad Leaf Plants, Shena Ruane May 2000

Synthesis Of Fluroxypyr For The Use On Broad Leaf Plants, Shena Ruane

Masters

Fluroxypyr, 1-methylheptyl (4-amino-3,5-dichloro-6-fluoro-2-pyridinyloxy) acetate is used for the control of annual broad leaf weeds in cereals and perennial rye grass. The objective of this work was to develop an economically viable process for the bench synthesis of an organic herbicide fluroxypyr and to scale up the reaction to two litres. This was carried out according to a technical bulletin received from Agriguard Ltd. In addition an investigation into the synthesis and characterisation of impurities formed and reported to be formed, in the reaction process was carried out. The process developed began with pentachloropyridine which on reaction with potassium fluoride in …


Synthesis Of The Fungicide Propiconazole A Systemic Foliar Fungicide., Hazel Delaney Mar 2000

Synthesis Of The Fungicide Propiconazole A Systemic Foliar Fungicide., Hazel Delaney

Masters

Propiconazole, 1-[[2-(2,4-dichlorophenyl)-4-propyl-1, 3-dioxol-2-yl[methyl]-1H-1,2,4-triazole, commercially know as “Tilt” is a systemic foliar fungicide for cereals and is widely used in agriculture. The aim of this project was to develop an economically feasible process for the production of propiconazole and to maximise the yields of the intermediates in the developed process. Processes investigated included the original Ciba-Geigy process. In addition an investigation into the synthesis and characterisation of the impurities formed, and reported to be formed in each step of the reaction process was carried out and seven of the reported impurities were synthesised. One impurity was shown not to be present …


Electroanalysis Using Differential Pulse Methods And Stripping Techniques., Enda Howard Jan 2000

Electroanalysis Using Differential Pulse Methods And Stripping Techniques., Enda Howard

Masters

Application of a differential pulse waveform to a microelectrode or a rotating disk electrode results in a peaked response for amperometric redox reactions. Based on these observations models were proposed and tested for these methods. Simulations of the models were carried out by inputting the relevant equations into Microsoft Excel. The microelectrode study revealed a good correlation between one model and the numerical derivative of the current following a linear sweep potential waveform. Experimentally the derivative can be obtained numerically following a linear sweep. The alternative differential pulse waveform requires more sophisticated equipment and the response can be affected by …


The Development And Validation Of A Methodology For The Analysis Of Polyaromatic Hydrocarbons In Air Particulates (Indoor And Outdoor), Kathryn O'Malley Jan 1999

The Development And Validation Of A Methodology For The Analysis Of Polyaromatic Hydrocarbons In Air Particulates (Indoor And Outdoor), Kathryn O'Malley

Masters

PAH form a large class of ubiquitous pollutants mainly of anthropogenic origin. Several PAH found in air particulates have been identified as carcinogens and mutagens. Sixteen of these PAH have been listed by the USEPA as priority pollutants. This research is concerned with the development and optimisation of a method for the analysis of these sixteen PAH in air particulates. Soxhlet and ultrasonic extraction procedures were investigated to optimise the recoveries from spiked glass fibre filters with a standard 1ppm mixture of the 16PAH. Standard mixtures of the 16 PAH were analysed by HPLC with fluorescence detection with approx. linearity …


Studies On The Amylolytic Breakdown Of Damaged Starch In Cereal And Non-Cereal Flours, Karen Bailey Jan 1999

Studies On The Amylolytic Breakdown Of Damaged Starch In Cereal And Non-Cereal Flours, Karen Bailey

Masters

The term starch damage refers to a number of changes to the starch granule structure, which are detectable by different analytical techniques. Damaged starch is the substrate for amylases, which in turn provides carbohydrates that are used in the production of certain foods and food ingredients; as a result, therefore, determination of levels in flours is a procedure carried out routinely by many manufacturers of starch based products. Enzymatic assay methods emulate the susceptibility of damaged starch granules to enzymatic attack. The first aim of this study was to evaluate enzymatic methods(1,2) to determine damaged starch in wheat flours and …


Reactions Of Chlorine Atoms With Aromatic Compounds, Barbara O'Leary Oct 1998

Reactions Of Chlorine Atoms With Aromatic Compounds, Barbara O'Leary

Masters

This thesis presents the results of kinetic studies on the reactions of chlorine atoms with a series of aromatic compounds. (please see full text for complete abstract)


Solvent Impregnated Resins For The Recovery Of Gold From Gold(I)Thiourea Solutions, Fiona Fitzpatrick Jan 1997

Solvent Impregnated Resins For The Recovery Of Gold From Gold(I)Thiourea Solutions, Fiona Fitzpatrick

Masters

Solvent Impregnated Resins (SIRs) are high surface area, macroporous, polymeric resins which have been physically impregnated with an organic solvent. In this research, three resins have been impregnated with Di-2-ethylhexyl phosphoric acid, a solvent which has shown selectivity to gold. The ability of the resins to recover gold (1) thiourea perchlorate from solution has been investigated. The resins have been studied both bare and when impregnated with the solvent and their efficiency was seen to increase upon impregnation. The overall efficiency of the resins was found to be pH dependent. It is also related to the level of impregnation of …


Synthesis And Characterisation Of New Dimolybdenum (Ii,Ii) Dicarboxylates And Their Use As Polymerization Catalysts, Elizabeth Whelan Aug 1996

Synthesis And Characterisation Of New Dimolybdenum (Ii,Ii) Dicarboxylates And Their Use As Polymerization Catalysts, Elizabeth Whelan

Masters

The purpose of this work was to prepare a series of new dimolybdenum(II,II) dicarboxylate complexes, to characterize the complexes and to investigate their use as potential catalysts for the ring-opening metathesis polymerization (ROMP) of the bicyclic monomer norbornene.


Aspects Of Gold Recovery From An Indigenous Ore, Cormac Patrick Mcnamee Jan 1993

Aspects Of Gold Recovery From An Indigenous Ore, Cormac Patrick Mcnamee

Masters

This project involved the investigation into the basic electrochemistry of the thiourea-formamidine disulphide redox couple and an estimation of the formal potential, Eo1 for the couple. By carrying out optimisation experiments on the leaching of gold from an ore sample from the Avoca mine in Co. Wicklow, the optimum leaching conditions were determined for maximum gold extraction. The effects of various organic and inorganic species on the adsorption of gold onto activated carbon and modified peat were investigated with the use of factorial designed experiments. The Langmuir Isotherm model was applied to estimate the capacity of the carbon for these …