Brominated flame retardants (BFRs) are chemicals used in e.g. electronic equipment, textiles and plastics for the prevention of fire. Over recent decades, concern has been raised regarding some heavily used BFRs, since the levels in the environment have been increasing. In the present thesis, persistent, bioaccumulative, and toxic (PBT) properties were studied for a structurally varied set of BFRs selected to represent more than 60 organic BFRs. The studied BFRs include: 2,4,4'-tribromodiphenyl ether (BDE 28), 2,2',3,4,4',5',6-heptabromodiphenyl ether (BDE  183), decabromodiphenyl ether (BDE 209), hexabromocyclododecane (HBCD), tetrabromobisphenol A (TBBPA), tetrabromobisphenol A 2-hydroxyethyl ether (TBBPA OHEE), 2,4,6-tribromophenol (246BrPh), 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (TBECH), and hexabromobenzene (HxBrBz). It is likely that soil will act as a sink for BFRs. Therefore, studies of BFRs were performed on persistence in soil, and on bioaccumulation from soil in the earthworm Eisenia fetida. Large variation in the biodegradability in soil among the tested BFRs was observed. The studied brominated diphenyl ethers (BDE 28 and BDE 209) were very persistent under both aerobic and anaerobic conditions, while 246BrPh and TBECH degraded quickly in both aerobic and anaerobic soil. The bioaccumulation in earthworm from soil was high for HxBrBz, TBECH and for tested brominated diphenyl ethers with 4-6 bromine atoms (BDE 47, BDE 99, and BDE 153). Bioaccumulation was also studied in zebrafish after dietary exposure to a mixture of BFRs. It was shown that several metabolites were formed and retained in zebrafish, which highlights the importance of also searching for and identifying persistent degradation products. Maternal transfer was shown for all BFRs present in the female zebrafish. This shows that zebrafish young (fry) are exposed to these BFRs at approximately the same concentrations as female zebrafish during the early-life stages, when fish are usually most sensitive to organic contaminants. Toxicity of individual BFRs and a BFR mixture was studied in Nitocra spinipes using a silica gel-based system. Highest toxicities were observed for BDE 28, TBBPA, and TBBPA OHEE. In the mixture toxicity study, simultaneous exposure to low concentrations (individually causing no significant effect) of six BFRs significantly affected the survival of Nitocra spinipes. The results from the PBT studies presented in the thesis and literature data were compared with the criteria for PBT classification, as set in the European REACH legislation. Further, some BFRs with physico-chemical properties similar to those of identified PBTs were suggested to be prioritized for future PBT testing.

Thesis (M.A.)--University of South Florida, 2006. / Title from PDF of title page. Document formatted into pages; contains 52 pages. Includes bibliographical references.

Les ligands multidentes montrent généralement de très bonnes activités dans la catalyse organométallique au palladium à faibles charges. Parmi ces ligands, l'utilisation des ligands polyphosphines ferrocéniques mènent à des résultats intéressants. Des systèmes catalytiques palladium/triphosphine ferrocénique robustes ont permis d'obtenir d'une part des diarylamines et d'autre part des éthers d'aryle et d'hétéroaryle avec de faibles charges catalytiques. Des calculs théoriques de DFT sur le cycle catalytique lors de la formation d'éthers d'aryle et d'hétéroaryle ont été réalisés. La présence d’un troisième groupement phosphino permettrait de stabiliser les états de transition et accélèrerait l’élimination réductrice. Les triarylamines ont pu être obtenues à l'aide d'une diphosphine ferrocénique avec une charge de 2 mol% de palladium. Des résultats modérés à excellents ont été obtenus. Enfin, les thioéthers d'aryle et d'hétéroaryle ont été obtenus avec d'excellents résultats à l'aide d'une tétraphosphine ferrocénique en présence de 0,2 mol% de palladium / Multidentate ligands usually show great activities in low loading organometallic catalysis in palladium. Among these ligands, the use of ferrocenyl polyphosphane ligands give interesting results. Robust palladium-ferrocenyl triphosphane catalytic systems have permitted to obtain biarylamines and aryl-heteroaryl ethers in the presence of low catalytic loadings. DFT studies on catalytic cycle during formation of aryl-heteroaryl ethers were carried out. The presence of third phosphino group stabilizes a transition state which enhances the rate of the reductive elimination. Triarylamines were obtained with ferrocenyl diphosphane in the presence of 2 mol% of palladium loading. Moderate to excellent results were obtained. Finally, aryl-heteroaryl sulfides were obtained with excellent results with ferrocenyl tetraphosphane ligand in the presence of 0.2 mol% of palladium.

Polybrominated dibenzo-p-dioxins (PBDD) and dibenzofurans (PBDF) are a group of compounds of emerging interest as potential environmental stressors. Their structures as well as toxic responses are similar to the highly characterized toxicants polychlorinated dibenzo-p-dioxins. High levels of PBDDs have been found in algae, shellfish, and fish, also from remote areas in theBaltic Sea. This thesis presents studies on PBDD behavior in fish and offspring, and natural formation of PBDDs from naturally abundant phenolic precursors. The uptake, elimination, and maternal transfer of mono- to tetraBDD/Fs were investigated in an exposure study reported in Paper I. The effects of PBDDs in fish were examined in a dose-response study (Paper II). It was shown that fish can assimilate PBDD/Fs from their feed, although non-laterally substituted congeners were rapidly eliminated. Laterally substituted congeners were retained as was congeners without vicinal hydrogens to some extent. PBDD/Fs were transferred to eggs, and congeners that were rapidly eliminated in fish showed a higher transfer ratio to eggs. Exposure to the laterally substituted 2,3,7,8-TeBDD had significant effects on the health, gene expression and several reproduction end-points of zebrafish, even at the lowest dose applied. The geographical and temporal variations of PBDD in biota samples from the Baltic Seasuggest biogenic rather than anthropogenic origin. In Paper III, bromoperoxidase-mediated coupling of 2,4,6-tribromophenol yielded several PBDD congeners, some formed after rearrangement. The overall yield was low, but significantly higher at low temperature, and the product profile obtained was similar to congener profiles found in biota from the Swedish West Coast. In Paper IV, photo­chemi­cally induced cyclization of hydroxylated polybrominated diphenyl ethers under natural conditions produced PBDDs at percentage yield. Rearranged products were not detected, and some abundant congeners do not seem to be formed this way. However, the product profile obtained was similar to congener profiles found in biota from the Baltic Proper. Since the PBDD congeners found in biota have a high turn-over in fish, the exposure must be high and continuous to yield the PBDD levels measured in wild fish. Thus, PBDDs must presumably be formed by common precursors in general processes, such as via enzymatic oxidations, UV-initiated reactions or a combination of both. The presented pathways for formation of PBDDs are both likely sensitive to changes in climatic conditions.

Le méconium constitue les premières selles du nourrisson. Cette matrice complexe est analysée dans le cadre du projet « PENEW » (Pregnancy Environment and NEWborn malformations) afin de déterminer si le degré d'exposition fœtale aux xénobiotiques joue un rôle dans la survenue de malformations congénitales. Le but de cette étude était le développement analytique pour la détection et la quantification dans le méconium d’une quarantaine de composés de familles différentes (composés organiques volatils, pesticides, éthers de glycol et les métabolites associés). Trois techniques analytiques différentes et une préparation d’échantillon spécifiques ont été développées pour la détection et la quantification de ces composés dans le méconium. L’application des ces méthodes à 246 échantillons de méconium a montré une exposition fœtale à plusieurs des substances recherchées. / Meconium is the earliest stool of newborns. This complex matrix was analyzed through the "PENEW" project (Pregnancy and Newborn malformations Environment) to determine if the degree of fetal exposure to xenobiotics has an influence in the occurrence of birth defects. The objective of this thesis was developed analytical methods for the detection and quantification of several different families of compounds (volatile organic compounds, pesticides, glycol ethers and their metabolites) in meconium. Three different analytical methods and a specific sample preparation have been developed for the detection and quantification of these compounds in the meconium. The application of these methods to 246 meconium samples showed a fetal exposure to several target compounds.

L'épuisement des réserves pétrolières et l'augmentation de la concentration du gaz à effet de serre CO2 sont les deux principaux problèmes connus liés à l'utilisation des carburants fossiles. Les biocarburants apparaissent comme un des moyens permettant à la fois une diminution de la dépendance au pétrole et une réduction de l'impact néfaste des moteurs automobiles sur l'environnement. Les biocarburants sont en effet considérés comme une source d'énergie renouvelable. L'objectif de cette thèse était de développer et valider les modèles cinétiques de combustion des composés oxygénés de biocarburants : l'éthanol, les biocarburants de deuxième-génération des familles du furane (furane, 2-méthylfurane, 2,5-diméthylfurane), du tétrahydrofurane (tétrahydrofurane, 2-méthyltétrahydrofurane) et le tétrahydropyrane, en utilisant les nouvelles données obtenues en flamme laminaire pré-mélangée à basse pression. De 20 à 60 produits ont été quantifiés par chromatographie en phase gazeuse et identifiés par couplage avec la spectrométrie de masse. Les résultats obtenus ont ensuite été utilisés pour analyser les voies de consommation des réactifs et de formation des produits, surtout pour les polluants, dans le but de mieux comprendre la chimie de la combustion de ces biocarburants. Ce rapport comprend 5 chapitres et une conclusion. Le premier chapitre présente une revue bibliographique des travaux antérieurs sur l'oxydation de l'éthanol et des éthers cycliques. Dans le second chapitre, le dispositif expérimental est décrit, en détaillant en particulier les nouveaux développements. Enfin les chapitres 3, 4, 5 présentent les résultats de l'étude de la combustion des composés étudiés / The decrease of petroleum reserves and the increase of concentration of greenhouse gas CO2 are the two major known problems related to the use of fossil fuels. Bio-fuels appear as a means allowing a decrease of the dependence on fossil fuels and a reduction of the harmful impact of engine on the environment. Bio fuels are considered as a source of renewable energy. The aim of this thesis was to develop and validate experimentally the high temperature kinetic models for the combustion of oxygenated compounds of bio-fuels: ethanol, second-generation bio-fuels of families of furan (furan, 2-methylfuran, 2,5-dimethylfuran), of tetrahydrofuran (tetrahydrofuran, 2 methyltetrahydrofuran), and tetrahydropyran, using new data obtained in laminar premixed low-pressure flame. About 20-60 products were quantified by gas chromatography and identified using mass spectrometry. The results obtained were then used to analyze the consumption pathways of fuels and the formation pathways of products, especially for pollutants, in order to better understand the combustion chemistry of these bio-fuels. This thesis report includes 5 chapters and a conclusion. The first chapter presents a review of the major works already published in the literature for the oxidation of ethanol and cyclic ethers. In the second chapter, the experimental setup of laminar premixed flame with the analytical techniques is described, detailing in particular new developments. Eventually, chapters 3, 4, 5 present the experimental and modeling results of the study of the combustion chemistry of the compounds studied

This diploma thesis deals with the study of the influence of cellulose ethers on the properties of hydraulic lime mortars. The availability and price of cellulose ethers in the industrial market is very favorable, but we can´t meet with studies using cellulose ethers in building materials, where lime is used as a binder. Cellulose ethers are commonly used as thickening agents in cement-based materials. The purpose of this diploma thesis is to review if cellulose ethers are appropriate for use in hydraulic lime mortars, either as water retention agents that contribute by water retention to better hydration of hydraulic binder components or to affect the properties of mortar in the fresh state. The theoretical part is dedicated to cellulose ethers, especially their production and how they influence the properties of building materials. In the practical part, the thesis deals with the influence of the dose of five different types of cellulose ethers on the properties of hydraulic lime. The properties in the fresh state and the physical-mechanical properties of mortars were monitored over time.

Our research involved two projects: Crown Aza and Crown ether. Crown Aza are compounds that have nitrogens as the hetero-atoms in the macrocycle. In the first aim, the 1 H NMR spectrum of strongly-coupled di-iron complexes shows 5 different conformations, but is unable to identify these conformers. Calculation using Density Functional Theory (DFT) were performed to attempt to quantify these conformers to correlate with the experimental NMR data. The second aim of this study was to utilize the carbonyl functional group of the macrocycles to couple the iron complexes to obtain tetramers or higher oligomers. Visible spectra of the selective reduction of iron mono-keto-macrocycles with boron trifluoride and triethylsilane showed a coupling reaction to form a di-iron complex. A mixture of iron mono-keto-macrocycic with iron diketo-dimacrocycle showed a new species with an intense NIR absorption at 1010 nm. This intense band at 1010 nm is extremely rare in transition metal compounds and is of potential interest in photodynamic therapy. This indicates a new species is formed with a very low energy gap between the ground and excited states. Our second interest is in ionizable crown ethers that have many potential applications from environmental to medical. These macrocyclic poly-ethers contain phosphorous and oxygen atoms which produce a charged moiety in the ring to form a neutral complex with our targeted ions. They are significantly different from all ionizable cyclic poly-ethers in the literature. They vary in ring size from 16-crown-6 to 22-crown-8 using ethylene or propylene linkages between the oxygen atoms. Theoretical calculations revealed these ionizable crown ethers can accommodate ions from 2.6 angstroms to 4.2 angstroms in diameter. Strontium 90 ( 90 Sr 2+ ) is a radioactive product ion from nuclear fission reactions. The Phosphorous containing macrocyclic poly-ether with 2 charges could form complexes with Strontium and are possible candidates for clean-up agents of radioactive materials. The synthesis of ionizable crown ethers is discussed.

No description available.

Tailored fluoropolymers remain the leading choice for a wide variety of advanced high-performance applications, including electronic/optical and energy conversion, owing to their unique blend of complementary high-performance properties. Amorphous semi-fluorinated polymers exhibit improved solubility and melt processability when compared to traditional perfluoropolymers. A leading class of semi-fluorinated aryl ether polymers includes perfluorocyclobutyl (PFCB), perfluorocycloalkenyl (PFCA), and fluoroarylene vinylene ether (FAVE) polymers. Monomers containing aromatic trifluorovinyl ethers (TFVE) are used to synthesize PFCB polymers via radical-mediated [2+2] cyclodimerization. On the other hand, FAVE and PFCA polymers are polymerized via base-mediated nucleophilic addition/elimination of bisphenols with TFVE monomers and decafluorocyclohexene respectively. The use of different monomer cores (aromatic, aliphatic, contorted, and renewable) should help to develop general structure/property relationships for this versatile and expanding approach to semi-fluorinated aryl ether polymers. The enchainment of polycyclic aromatic hydrocarbon (PAH) cores with functional fluorocarbon groups (or segments) recently afforded a new class of semi- fluorinated polymers in the continuing quest for novel organic materials for potential applications in optoelectronic, gas-separation, and advanced composites. Chapter 2 details the incorporation of commercially available acenaphthenequinone was achieved to afford PFCB aryl ether polymers with excellent solubility, high thermal stability, and film-forming capability. Chapter 3 represents base-promoted nucleophilic addition/elimination of commercial bisphenols with TFVE-triphenylene monomers affording FAVE aryl ether polymers possessing excellent solution processability, high thermal stability and photostability. In addition, triphenylene-enchained FAVE polymers exhibit extreme thermal-oxidative photostability and emit blue light after heating in air at 250 °C for 24 h. Further, time-dependent density functional theory (TD-DFT) computations were performed to understand electronic polymer structures. In one case, post-polymerization Scholl coupling converted the central triphenylene core to afford a hexabenzocoronene containing semi-fluorinated polymer with new optoelectronic properties. Chapter 4 demonstrates synthesis and characterization of renewable semi-fluorinated polymers obtained using aliphatic diol isosorbide. This renewable diol readily polymerizes with bis-TFVE derivatives of bisphenol A and 6F to provide high molecular weight thermoplastics exhibiting excellent solubility and tough, transparent film-forming capability. Finally, Chapter 5 presents synthesis of TFVE enchained corannulene which gave blue-light emission and outstanding processability. Synthesis and characterization, including the new materials' optical, thermal, and electronic properties, is presented.