A novel crown ether precursor was developed in which a rigid 4-oxahexacyclo (5.4.1.26.3,10.05,9.08,11) dodecyl cage moiety ("cage functionality") was incorporated.

This thesis involves a study of the thermodynamics of liquid mixtures containing N-methyl-2pyrrolidone (NMP) and hydrocarbons or ethers. NMP is a polar liquid which is used in liquid extraction procedures for the separation of polar and nonpolar hydrocarbons. It was considered important enough to devote an entire thesis to the properties of NMP related to its interactions with simple hydrocarbons and ethers. The thesis consists of four parts: Part one is devoted to liquid-liquid equilibria. Experimental results at 298.2 K, are presented for the mixtures: NMP + an aromatic hydrocarbon + an n-alkane. Firstly, the effect increasing the chain length of the alkane has on the liquid-liquid equilibria was investigated, by studying mixtures of the type: an n-alkane + toluene + NMP; where the n-alkane refers to n-hexane or n-nonane or n-tetradecane or n-hexadecane. Secondly, the effect of substitution on the benzene ring on the equilibria was studied by measuring the liquid-liquid equilibria for the mixtures: n-hexadecane + an aromatic hydrocarbon + NMP; where the aromatic hydrocarbon refers to toluene or o-xylene or m-xylene or p-xylene or mesitylene or ethyl benzene. The chain length of the n-alkane had a significant effect on the liquid-liquid equilibria. Methyl substitution on the benzene ring had a small effect on the liquid-liquid equilibria. Part two is devoted to activity coefficients at infinite dilution. Experimental results at 298,15 K, determined using gas-liquid chromatography, are presented for the mixtures: NMP (solvent) + n-pentane or n-hexane or n-heptane or n-octane or cyclopentane or cyclohexane or cycloheptane or I-hexene or 1-heptene or l-octene or diethyl ether or diisopropyl ether. The magnitudes of the infinite dilution activity coefficients had the following order: n-alkanes > cycloalkanes > l-alkenes > ethers. Part three is devoted to excess molar enthalpies. Experimental results at 298.15 K are presented for the mixtures: NMP + an aromatic hydrocarbon. Here, an aromatic hydrocarbon refers to one of benzene or toluene or o-xylene or m-xylene or p-xylene or mesitylene or ethyl benzene. Isothermal flow microcalorimetry was used to determine the excess molar enthalpies. Increased methyl substitution on the' benzene ring manifests itself as a reduction in the association between NMP and the aromatic hydrocarbon. Part four is devoted to excess molar volumes. Experimental results at 298.15 K are presented for the mixtures: NMP + an aromatic hydrocarbon. Here, an aromatic hydrocarbon refers to one of benzene or toluene or o-xylene or m-xylene or p-xylene or mesitylene or ethyl benzene. Densitometry was used to determine the excess molar volumes. The excess molar volumes were negative for all the mixtures. / Thesis (M.Sc.)-University of Natal, 1997.

Os éteres de bifenilas polibromados (PBDEs) são largamente usados como retardadores de chama e têm sido detectados no sangue humano, tecido adiposo e leite materno devido às suas propriedades físico-químicas e bioacumuladoras e à sua elevada persistência no meio ambiente. Muitos estudos têm relatado toxicidade hepática relacionada à exposição aos PBDEs. Como efeitos citotóxicos são frequentemente associados à disfunção mitocondrial,no presente estudo, investigamos a toxicidade do BDE-47 em mitocôndrias isoladas de fígado de rato. Nos seguintes parâmetros: potencial de membrana mitocondrial, consumo de oxigênio, interação com a membrana mitocondrial, liberação de cálcio, inchamento mitocondrial e os níveis de ATP da suspensão mitocondrial com a finalidade de observar a capacidade do composto em interferir com a bioenergética da organela. Avaliou-se ainda a formação de espécies reativas de oxigênio (ROS), dos níveis de GSH/GSSG, níveis mitocondriais de grupos sulfidrila de proteínas e níveis mitocondriais de NAD(P)H com o intuito de analisar o estado redox mitocondrial. Os congêneres BDE-47 e BDE-99 foram avaliados em concentrações que variaram entre 0,1 e 50 ?mol/L. Os dois congêneres de PBDEsapresentaram toxicidade mitocondrial afetando todos os parâmetros que avaliam a bioenergética mitocondrial culminandoum uma depleção do ATP. Por outro lado, nos ensaios de avaliação do estresse oxidativo os PBDEs estudados não demonstraram qualquer efeito, no entanto, afetaram a cadeia respiratória mitocondrial, o que normalmente reflete em um acúmulo de espécies reativas de oxigênio. Estes resultados são explicados pelo mecanismo de ação destes compostos como retardante de chama, pois durante a combustão os retardantes de chama bromados realizam a neutralização de radicais livres (OHo e Ho). Conclui-se assim que os PBDEs podem levar à disfunção bioenergética e assim induzir a morte celular pela diminuição do ATP. Observou-se ainda que BDE-47 apresentou maior toxicidade do que o BDE-99 sobre os parâmetros estudados. / Polybrominated biphenyls ethers (PBDE) , widely used as flame retardants, have been detected in human blood, adipose tissue and breast milk due to their physicochemical and high bioaccumulative properties and environmental persistence. Many studies have reported liver toxicity related to exposure to PBDEs. As cytotoxic effects are often associated with mitochondrial dysfunction,in the present study, we investigated the toxicity of the BDE-47 and BDE-99 on isolated rat liver mitochondria. Assessing mitochondrial membrane potential, oxygen consumption, interaction with the mitochondrial membrane, calcium release, mitochondrial swelling and ATP levels of the mitochondrial suspension in order to observe the ability of the compounds to interfere with the bioenergetic organelle, and the formation of reactive oxygen species (ROS), GSH/GSSG levels, mitochondrial sulfhydryl groups and levels of mitochondrial NAD(P)H in order to analyze mitochondrial redox state. The congeners BDE-47 and BDE -99 were evaluated at concentrations ranging between 0.1 and 50 ?mol/L. Both PBDEs congeners showed mitochondrial toxicity affecting all parameters that assess mitochondrial bioenergetics and culminating with ATP depletion. On the other hand, no effect was observed in tests assessing oxidative stress, although they were able to inhibit the mitochondrial respiratory chain, which is usually reflected in an accumulation of reactive oxygen species. These results are explained by the mechanism of action of this compounds as flame retardants, because during the combustion brominated flame retardants perform the neutralization of free radicals (OHo and Ho). It follows that PBDEs can lead to mitochondrial dysfunction and thus induce bioenergetic cell death. It was also observed that The BDE-47 showed higher toxicity than BDE-99 in the studied model

Kwong Tsz Yan Alex. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 77-84). / Abstracts in English and Chinese. / Abstract --- p.i / Declaration --- p.iii / Acknowledgement --- p.iv / Table of contents --- p.v / List of tables --- p.ix / List of figures --- p.x / Chapter Chapter One : --- Introduction --- p.1 / Chapter 1.1 --- The outbreak of SARS --- p.1 / Chapter 1.2 --- Characteristics of triclosan --- p.2 / Chapter 1.3 --- Environmental fate of triclosan --- p.3 / Chapter 1.4 --- Treatment methods for triclosan --- p.5 / Chapter 1.5 --- Ti02 photocatalysis --- p.6 / Chapter 1.6 --- Addition of hydrogen peroxide to the photocatalytic system --- p.9 / Chapter 1.7 --- Gas chromatography/ ion trap mass spectrometry analysis --- p.10 / Chapter 1.8 --- Scope of work --- p.11 / Chapter Chapter Two : --- Experimental --- p.13 / Chapter 2.1 --- Chemical reagents --- p.13 / Chapter 2.2 --- Photocatalytic experiments --- p.14 / Chapter 2.3 --- "Analysis of 2,8-DCDD and triclosan by GC/ITMS" --- p.15 / Chapter 2.4 --- Optimization of GC/ITMS conditions --- p.17 / Chapter 2.5 --- Analysis of other reaction intermediates by GC/MS (full scan mode) --- p.18 / Chapter 2.6 --- "Analysis of 2,4-dichlorophenol and triclosan by GC/MS (SIM mode)" --- p.20 / Chapter 2.7 --- Effect of hydrogen peroxide concentration on triclosan degradation --- p.20 / Chapter 2.8 --- Determination of total organic carbon (TOC) removal --- p.21 / Chapter 2.9 --- UV-Visible spectrometry --- p.21 / Chapter Chapter Three : --- Results --- p.22 / Chapter 3.1 --- Selection of precursor ions for GC/ITMS analysis --- p.22 / Chapter 3.2 --- Optimization of GC/ITMS conditions --- p.25 / Chapter 3.3 --- "Analysis of 2,8-DCDD and triclosan by GC/ITMS" --- p.27 / Chapter 3.4 --- "Analysis of 2,4-dichlorophenol and triclosan by GC/MS (SIM mode)" --- p.29 / Chapter 3.5 --- "Quantitative measurement of 2,8-DCDD in UV irradiated samples" --- p.31 / Chapter 3.6 --- Photocatalytic oxidation of triclosan by UV at 365nm --- p.33 / Chapter 3.7 --- TOC removal in triclosan degradation --- p.35 / Chapter 3.8 --- Identification of intermediates in photocatalytic oxidation of triclosan --- p.36 / Chapter 3.9 --- Quantitative measurement of the intermediates in photocatalytic oxidation of triclosan --- p.41 / Chapter 3.10 --- Effect of hydrogen peroxide concentration on triclosan degradation --- p.43 / Chapter 3.11 --- Effect of hydrogen peroxide concentration on TOC removal --- p.46 / Chapter 3.12 --- "Effect of hydrogen peroxide concentration on 2,4-dichlorophenol generation during triclosan degradation" --- p.47 / Chapter 3.13 --- "Photocatalytic degradation of 2,4-dichlorophenol" --- p.49 / Chapter 3.14 --- "Identification of intermediates in photocatalytic oxidation of 2,4-dichlorophenol" --- p.50 / Chapter 3.15 --- "Quantitative measurement of the intermediates in photocatalytic oxidation of 2,4-dichlorophenol" --- p.54 / Chapter Chapter Four : --- Discussions --- p.56 / Chapter 4.1 --- "Photochemical conversion of triclosan to 2,8-DCDD" --- p.56 / Chapter 4.2 --- Proposed mechanism of triclosan degradation --- p.57 / Chapter 4.3 --- "Proposed mechanism of 2,4-dichlorophenol degradation" --- p.63 / Chapter 4.4 --- TOC removal in triclosan degradation --- p.65 / Chapter 4.5 --- Effect of hydrogen peroxide concentration on photocatalytic oxidation of triclosan --- p.65 / Chapter 4.6 --- "Adverse environmental and human health effects of 2,8-DCDD" --- p.69 / Chapter 4.7 --- "Adverse environmental and human health effects of 2,4-dichlorophenol" --- p.71 / Chapter 4.8 --- "Discharge limitations for 2,4-dichlorophenol" --- p.73 / Chapter Chapter Five : --- Conclusions --- p.75 / References --- p.77

The alkoxytriphenylphosphonium ion intermediate of the Mitsunobu reaction for the esterification and inversion of configuration of an alcohol can be generated using the Hendrickson reagent, triphenylphosphonium anhydride trifluoromethanesulfonate, 27. While 27 was used in place of the Mitsunobu reagents (triphenylphosphine and a dialkyl azodicarboxylate) for the esterification of primary alcohols, the reaction failed with secondary alcohols such as (-)-menthol giving predominately elimination rather than the desired SN2 displacement. The difference between the two reactions was shown to be related to the more 'ionic' conditions generated when the Hendrickson reagent 27 was employed. An extreme sensitivity of the Mitsunobu reaction to the presence of salts was discussed and may indicate a mechanism involving ion pair clustering. Five-, six- and seven-membered cyclic analogues of the Hendrickson reagent 90-92 were prepared. A kinetic comparison of the cyclic analogues 90-92 revealed that a considerable increase in the rate of esterification could be achieved when the five-membered ring analogue 90 was used in a non-polar solvent such as toluene. Selected acyclic analogues of the Hendrickson reagent 27 possessing tributyl 118, tricyclohexyl 130 and diphenyl-2-pyridyl 137 functionalities were synthesised. However when 118, 130 and 137 were used for the attempted esterification of (-)-menthol, elimination was the major reaction pathway. Diphenyl-2-pyridylphosphonium anhydride triflate 137 was found to be a useful reagent for the synthesis of acyclic dialkyl ethers from primary alcohols. A polymeric version of the five-membered ring analogue 56, prepared by reaction of the polymer-supported 1,2-bis(diphenylphosphinyl)ethane 57 with triflic anhydride, was used for the preparation of simple esters and amides. A new dehydrating agent, polymer-supported triphenylphosphine ditriflate 157, was readily prepared from the oxidised form of commercially available polymer-supported triphenylphosphine and triflic anhydride. A wide range of dehydration-type reactions, such as ester, amide, anhydride, peptide, ether and nitrile formation, were performed in high yield using polymer-supported triphenylphosphine ditriflate 157. The reagent 157 was easily recovered and re-used several times without loss of efficiency. The use of 4-dimethylaminopyridine allowed the esterification of secondary alcohols with 157 to proceed without elimination and gave esters in high yield but with retention of configuration. Both reagents 56 and 157 provide an alternative to the Mitsunobu reaction, where the use of azodicarboxylates and chromatography to remove the phosphine oxide by-product can be avoided. However, the Mitsunobu reaction retains its supremacy for the inversion of configuration of a secondary alcohol. Preliminary investigations on the phosphityation of alcohols via the Hendrickson reagent 27, 1,3-benzodioxole formation using the Mitsunobu reaction and azodicarboxylate alternatives in the Mitsunobu reaction are described.

The purpose of this study was to optimize and investigate crown ether analysis by using a mass spectrometer equipped with a direct insertion solids probe. The typical aliphatic and aromatic crowm ethers, 18-crown-6 and dibenzo-18-crown-6 were chosen for the study. The crown ether samples were prepared by miximg with the reagents (some inorganic and organic salts and glycine) or being supported on the support materials (diatomite and glass supports) in a 1:10 ratio by weight as the samples for testing. The pure crown ethers and their mixtures were tested by the programmed temperature direct insertion probe mass spectrometer. The effects of the reagents and support materials on the peak maximum temperature (Tm) and the spectra of the crown ethers were studied. The results Tm of the crown ethers to increase significantly, and glycine and ammonium salts interfered the spectra of the crown ethers. The effect of sample size and "concentration" on Tm of the crowns also was investigated. The bigger sample size caused the Tm to be higher. No significant effect of the "concentration" on Tm was observed. It was concluded that tha smaller sample size provided better spectra with less interfererences and that some thermally stable reagents or support materials could be used to facilitate the sampling of crown ethers. More detailed study of the effects of iodides on Tm was recommended. In addition, more detailed investigation of the approach of using a CI source without reagent gases is needed. Switching to the CI configuration appears to be a simple and effective method for providing complementary information about the molecules.Ball State UniversityMuncie, IN 47306

Thesis (Ph. D.)--Institute of Paper Chemistry, 1940. / Includes bibliographical references (p. 96-97).

Thesis (Ph. D.)--Institute of Paper Chemistry, 1950. / Bibliography: leaves 143-146.

Not available / text

No description available.