A method based on headspace solvent microextraction (HSME) technique followed by gas chromatography with flame ionization detector (FID) was developed for the determination of four polycycHc aromatic hydrocarbons (PAHs) in water samples. The extraction capacity of two extraction solvents, l-butanol and octane have been studied and compared. The method was developed usmg spiked water samples in the concentration range 17.8 to 0.16 mg/L. l-butanol showed good extraction efficiency for the target compounds. An increase in the extraction efficiency of the PAHs was observec. when the parameters affecting the HSME process such as temperature, extraction time. salt additives and sample volume were optimized.

Following release to the environment, crude oil becomes subject to weathering processes which remove the simple, volatile hydrocarbons leaving an unresolved complex mixture (UCM) comprising the more environmentally persistent components. Aromatic UCMs have been reported in a wide variety of environmental matrices. Recent studies indicate such material, particularly monoaromatic hydrocarbons, is sufficiently bioavailable to marine organisms (e. g. mussels) to elicit toxicological responses. However, little else is known about the environmental fate and composition of petroleum-derived aromatic UCMs. The overall aim of this work was to investigate aromatic UCMs with particular emphasis on their biodegradability, water solubility and composition. To assess persistence in the environment, an 'aromatic' UCM was isolated from Tia Juana Pesado crude oil (Venezuela) and this UCM exposed to the hydrocarbon degrading bacterium Pseudomonas fluorescens (Texaco). Five synthesised alkylcyclohexyltetralins and an alkylcyclohexylnaphthalene, proposed previously as 'average' structures for some aromatic UCM components, were also exposed under the same conditions. After 50 days, biodegradation of the compounds had not exceeded 20%, the most resistant (-2% biodegradation) being those with C3-C5 alkyl chains. These latter results were comparable to those observed for the 'aromatic' UCM (-2%). Using North Sea oil or n-hexadecane as co-substrates, the synthetic compounds were also exposed to a natural consortium of bacteria to provide more environmentally realistic conditions. After 119 days the branched chain C5 homologue (-60%) and the naphthalene (-12%) still remained, yet under these severe conditions the components of the North Sea crude oil co-substrate were extensively degraded with even the highly bioresistant pentacyclic hopanes exhibiting biodegradation. Aqueous solutions of an 'aromatic' and 'monoaromatic' UCM were produced (at 25 'C) using a generator column technique. These 'solubilised' UCM fractions may represent UCM hydrocarbons which are bioavailable, and which are most toxic to aquatic organisms. An altered UCM was clearly evident in the aqueous phase extracts, suggesting that many of the compounds in the original aromatic and monoaromatic UCMs exhibited similar physicochemical properties and mole fractions. However, higher molecular weight hydrocarbons were absent from the generated 'solutions', indicating a solubility cut-off point based predominantly on molecular weight. The molecular weight distribution differed significantly for the 'solubilised' aromatic and monoaromatic UCMs, indicating that Raoult's Law may describe a critical control in the dissolution of complex mixtures. Comprehensive two-dimensional gas chromatography-time of flight-mass spectrometry (GCxGC-ToF-MS) analysis was used to provide vastly increased separation power and characterisation of a water 'soluble' monoaromatic UCM. Over 1200 compounds were separated by the chromatography, of which about 500 had distinct mass spectra from the ToF-MS analysis. A detailed characterisation of some of these monoaromatic UCM hydrocarbons via comparison to mass spectra registered in the NIST library permitted the identities of over 100 monoaromatic UCM components to be inferred. Compounds identified include novel alkylated homologues of benzene, indene, indan, tetralin, biphenyl, diphenylmethane and tetrahydrophenanthrene. This study has shown that a UCM appeared to be comprised of the geochernically minor isomers and analogues of known major crude oil constituents. This finding is extremely important given that the narcotic toxicity of petroleum hydrocarbons is additive. As UCMs often account for a large proportion of crude oil mass, these persistent residues may also contribute significantly to the observed narcotic toxicity of crude oil.

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Flavan-3-ols such as (—)-epicatechin and (+)-catechin are found in significant concentrations in red wine, green and black teas and cocoa. The radiolabelling of flavan-3-ols for feeding studies would require a short high-yielding route from the point of introduction of the label. (E)-1,3-Diarylpropenes had been key intermediates in previous syntheses of flavan-3-ols and so the modified Julia alkenation reaction between a labelled aryl aldehyde and a 2-(2'-arylethylsulfonyl)benzothiazole was proposed as the key step in the preparation of radiolabelled (E)-1,3-diarylpropene. A low molecular weight poly(ethyleneglycol)-monomethyl ether (MPEG, average MW 550) support would be used to improve the efficiency of isolating radiolabelled product after each reaction. The light MPEG support was attached to the starting aryl bromide by protecting the phenolic hydroxyl group with a new light MPEG α,α’-dioxyxylyl protecting group, introduced by reaction with light MPEG-supported benzylic bromide, to give supported aryl bromide. The aryl bromide was reacted with copper (I) cyanide to give MPEG-supported nitrile. In theory, 14C-labelled cyanide could be used in this step. Reduction and hydrolysis gave the aldehyde. Throughout the sequence MPEG solid-phase extraction (M-SPE) was used to assist purification. Several approaches to the synthesis of 2-(2'-arylethylsufonyl)benzothiazole were then investigated using a variety of model 2-arylethyl sulfones. The novel addition of phenylcopper to phenyl vinyl sulfone gave 2-phenethyl phenyl sulfone in good yield, but the reaction was less effective for sterically hindered arylcoppers and unsuccessful for the preparation of 2-(2'-arylethylsufonyl)benzothiazoles. Alkylcopper reagents were also suitable substrates for this novel coupling. Heck reaction between aryl iodide and phenyl vinyl sulfone, and reduction of the resulting alkene gave 2-arylethyl phenyl sulfone but the Heck reaction failed with benzothiazolyl analogues. Lithiated 2-(methylthio)benzothiazole reacted with aryl aldehydes to give β-hydroxy sulfides, but reduction to 2-arylethyl derivatives failed, even after oxidation of the sulfide to the sulfone or elimination to give a vinyl sulfide or sulfone. The same problem was encountered when lithiated 2-(trimethylsilylmethylthio)benzothiazole was use to make vinyl sulfides directly. However, alkylation of lithiated 2-(methylthio)benzothiazole with benzyl bromide gave 2-(2'-phenylethylsufonyl)benzothiazole in good yield. Unfortunately, the reaction could not be used to prepare phloroglucinol-derived benzothiazole. Finally, the benzothiazoles underwent modified-Julia alkenation reaction with electron-rich benzaldehydes to give (E)-1,3-diarylpropenes in high yield.

Ο στόχος την παρούσας εργασίας είναι η αποδόμηση των PAHs με χρήση όζοντος.Για το σκοπό αυτό επιλέξαμε το φαινανθρένιο ως ένωση-μοντέλο σε οργανικό διαλύτη, με απώτερο στόχο την επεξεργασία επικίνδυνων αποβλήτων. / The perpose of this study is the degradation of polycyclic aromatic hydrocarbons with ozon. For this reason we use phenanthrene like model-compound in organic solution.