No description available.

Graduation date: 1995

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

Thesis (Ph. D.)--Institute of Paper Chemistry, 1963. / Bibliography: leaves 114-117.

Orientador: Jose Augusto Rosário Rodrigues / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-24T08:17:01Z (GMT). No. of bitstreams: 1 Carvalho_PauloSergiode_D.pdf: 14146737 bytes, checksum: cce704fa63bb067ebc25618dac57ceb6 (MD5) Previous issue date: 2013 / Resumo: Este trabalho descreve uma metodologia para a síntese de 1,2- e 1,4-benzoquinona-monocetais através da oxidação de fenóis contendo uma cadeia hidróxi-alquílica lateral promovida por reagentes de iodo(III) hipervalente. 3-Hidróxi-?-metil-benzenopropanol e três derivados metoxilados foram preparados a partir dos respectivos benzaldeídos. Oxidações do 3-hidróxi-?-metil-benzenopropanol com um equivalente de diacetato de iodobenzeno (IBDA) ou [bis(trifluoroacetóxi)iodobenzeno] (BTIB) em diversos solventes não renderam o croman-6-ol esperado, mas apenas materiais poliméricos marrons. Entretanto, resultados interessantes foram obtidos das oxidações dos benzenopropanóis com dois equivalentes de IBDA em metanol ou 2,2,2-trifluoroetanol (TFE). Em metanol, 4,4-dimetóxi-cicloexa-2,5-dienonas e 6,6-dimetóxi-cicloexa-2,4-dienonas foram os produtos principais, enquanto que, em TFE, ciclizações da cadeia hidróxi-alquílica lateral não-rígida originaram monocetais semicíclicos de 1,2- e 1,4-benzoquinonas como produtos principais. A oxidação do 3-hidróxi-?-metil-4-metóxi-benzenopropanol em metanol rendeu um dímero de Diels-Alder mediante a cicloadição da respectiva cicloexa-2,4-dienona. As sínteses desses monocetais semicíclicos são importantes por se tratarem dos primeiros exemplos de cetais derivados de cromanóis obtidos por oxidações de fenóis contendo uma cadeia lateral não-rígida. A parte final do trabalho descreve as primeiras etapas de uma síntese do (S)-6-benzilóxi-2,5,7,8-tetrametil-croman-2-carbaldeído, proposta com base na metodologia desenvolvida. A síntese desse heterociclo representaria uma nova síntese formal da vitamina E (?-tocoferol). / Abstract: A methodology to the synthesis of 1,2- and 1,4-benzoquinone semicyclic monoketals through the oxidation of phenols bearing a hydroxy-alkyl side chain promoted by hypervalent iodine(III) reagents is described. 3-Hydroxy-?-methyl-benzenepropanol and three of its methoxy derivatives were prepared from the respective benzaldehydes. Oxidations of 3-hydroxy-?-methyl-benzenepropanol with one equivalent of iodobenzene diacetate (IBDA) or [bis(trifluoroacetoxy)iodobenzene] (BTIB) in a variety of solvents did not furnish the expected chroman-6-ol; instead, only red-brownish polymeric materials were produced. However, better results were achieved from the oxidations of the benzenepropanols by two equivalents of IBDA in methanol or 2,2,2-trifluoroethanol (TFE) as solvent. In methanol, 4,4-dimethoxy-cyclohexa-2,5-dienones and 6,6-dimethoxy-cyclohexa-2,4-dienones were the major products, whereas in TFE, cyclizations of the nonrigid hydroxy-alkyl side chain took place to furnish 1,2- and 1,4-benzoquinone semicyclic monoketals as main products. The oxidation of the 3-hydroxy-4-methoxy derivative in methanol yielded only a Diels-Alder dimer by the cycloaddition of the unstable intermediate cyclohexa-2,4-dienone. The syntheses of the semicyclic monoketals described here represent an important achievement since these are the first examples of semicyclic ketals related to chromanols obtained by the oxidation of phenols having a nonrigid hydroxy-alkyl side chain. The final part of this work describes the initial efforts towards the synthesis of (S)-6-benzyloxy-2,5,7,8-tetramethyl-chroman-2-carbaldehyde, proposed on the basis of the developed methodology. The synthesis of this heterocyclic compound would represent a new formal synthesis of vitamin E (?-tocopherol). / Doutorado / Quimica Organica / Doutor em Ciências