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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The isomer distribution in the sulfonation of iodobenzene

Knight, Joseph A. 01 July 1957 (has links)
Using the isotope dilution technique, the distribution of isomers was determined when iodobenzene was sulfonated with sulfur trioxide in liquid sulfur dioxide. The active isotope was S^35. Before this distribution could be established, it was necessary to prepare the pure isomers of iodobenzenesulfonic acid. These were prepared by diazotization of the corresponding aminobenzenesulfonic acids. Since o-aminobenzenesulfonic acid was not readily available, it was necessary that it be synthesized before the diazo reactions could be carried out. Considerable work has been done on the development of a method whereby the bromobenzenesulfonic acids could be synthesized and obtained in pure form. Some work has been done in preparing the isomers of chloro-benzenesulfonic acid. The S-benzylisothiuronium derivatives of the iodo-, and amino-, and bromobenzenesulfonic acids have been prepared, purified and their melting points determined. It has been established, that when iodobenzene is sulfonated there is considerable replacement of the iodine by sulfure trioxide to form benzenesulfonic acid. When p-iodobenzenesulfonic acid was subjected to sulfonation conditions, there was essentially no exchange between the sulfonic acid group and the sulfonation agent, from which we concluded that under these conditions, there was negligible reversibility.
2

Synthetic Investigation on the Biomimetic Metal-Catalyzed Sulfoxidations and Photochemical Generation of a Highly Reactive Ruthenium(V)-Oxo Porphyrin

Luo, WeiLong 01 July 2016 (has links)
Catalytic oxidation plays a crucial role in current chemical and pharmaceutical industries which is also a leading technology for green chemical processes. In Nature, the ubiquitous cytochrome P450 enzymes can catalyze a wide variety of oxidation reactions with high efficiency and selectivity. Many transition metal catalysts are designed as the biomimetic model of cytochrome P450 enzymes. In this work, series of metalloporphyrins and metallocorroles have been successfully synthesized to investigate and develop catalytic selective oxidation of sulfides to sulfoxides. Manganese(III) porphyrin complexes (2) and manganese(III) corrole complexes (6) with iodobenzene diacetate [PhI(OAc)2] as a mild oxygen source exhibited remarkable catalytic activity toward selective oxidation of sulfides to sulfoxides under mild conditions. Conspicuous is the fact that readily soluble PhI(OAc)2 in the presence of a small amount of water is more efficient than the commonly used PhIO and other oxygen sources under identical conditions. It was found that the reactivity of manganese(III) porphyrin catalysts was greatly affected by axial ligand and the weakly binding chlorate gave the highest catalytic activity in the oxidation of sulfide. Both porphyrin-manganese and corrole-manganese catalysts catalyzed the highly selective oxidation of para-substituted thioanisoles with PhI(OAc)2 in the presence of a small amount of water. Complete conversion and of sulfide and excellent selectivities for sulfoxide were achieved within 120 min. We discovered that photo-disproportionation of a bis-porphyrin-diruthenium(IV)- μ-oxo dimer gave a porphyrin-ruthenium(III) species and a putative poprhyrinruthenium( V)-oxo species that can be detected and studied in real time using laser flash photolysis methods. As determined by its spectral and kinetic behavior, the same oxo transient was also formed by photolysis of a porphyrin-ruthenium(III) N-oxide adduct. Second-order rate constants for reactions with several substrates at 22 °C were determined; representative values of rate constants were kox = 6.6 × 103 M-1 s-1 for diphenylmethanol, kox = 2.5 × 103 M-1 s-1 for styrene, and kox = 1.8 × 103 M-1 s-1 for cyclohexene.
3

The Pure Rotational Spectra of Diatomics and Halogen-Addition Benzene Measured by Microwave and Radio Frequency Spectrometers

Etchison, Kerry C. 08 1900 (has links)
Two aluminum spherical mirrors with radii of 203.2 mm and radii of curvature also of 203.2 mm have been used to construct a tunable Fabry-Perót type resonator operational at frequencies as low as 500 MHz. The resonator has been incorporated into a pulsed nozzle, Fourier transform, Balle-Flygare spectrometer. The spectrometer is of use in recording low J transitions of large asymmetric molecules where the spectra are often greatly simplified compared to higher frequency regions. The resonators use is illustrated by recording the rotational spectra of bromobenzene and iodobenzene. In related experiments, using similar equipment, the pure rotational spectra of four isotopomers of SrS and all three naturally occurring isotopomers of the actinide-containing compound thorium monoxide have been recorded between 6 and 26 GHz. The data have been thoroughly analyzed to produce information pertaining to bond lengths and electronic structures.
4

Reações de ésteres ß,Y-insaturados com tálio(III) e de 1,2-di-hidronaftalenos com iodo(III) / Reactions of ß,Y-unsaturated esters with thallium(III) and 1,2-dihydronaphthalenes with iodine(III)

Pedrozo, Eliane Corrêa 30 August 2006 (has links)
Esta dissertação apresenta um estudo sobre a contração de anel de ésteres ß,y-insaturados promovida por trinitrato de tálio (TTN) e de 1,2-di-hidronaftalenos promovida por hidroxi(tosiloxi)iodobenzeno (HTIB), também conhecido como reagente de Koser. Ambos estudos visaram à síntese de indanos funcionalizados. A reação de uma série de ésteres ß,y-insaturados (por exemplo 2-(3,4-di-hidronaftalen-1-il)-proprionato de etila) com TTN em ácido acético forneceu os correspondentes produtos de contração, formando indanos em bons rendimentos. A presença de grupos doadores de elétrons na posição 6 no anel aromático resultou no aumento do rendimento do produto de contração, enquanto que grupos atraentes de elétrons na posição 7 do anel aromático acarretou o decréscimo do rendimento do indano quando comparado a substratos que não são substituídos nesta posição. O aumento da cadeia alquílica na posição alfa-carbonila não interferiu no rendimento do produto desejado. O éster substituído por uma metila na posição 4 do anel ciclo-hexênico levou preferencialmente ao indano trans-1,3-dissubstituído. A reação do 1,2-di-hidronaftaleno com HTIB em metanol levou ao produto de contração de anel 1-dimetoximetil-indano com rendimento moderado, além dos produtos de adição cis e trans-1,2-dimetoxi-1,2,3,4-tetra-hidronaftaleno. No entanto, a reação desse substrato com HTIB em acetonitrila, diclorometano ou trimetil-ortoformiato forneceu o produto de aromatização (naftaleno). Contudo, os produtos de contração, 1-indano-1-il-etanona e 1-(3-metil-indan-1-il)-etanona foram formados em bons rendimentos quando o 4-metil-1,2-di-hidronaftaleno e o 1,4-dimetil-1,2-di-hidronaftaleno, respectivamente, foram tratados com HTIB em acetonitrila. No caso do 1,4-dimetil-1,2-di-hidronaftaleno há uma predominância na formação do isômero trans. Finalmente, para a reação de 4-metil-1,2-di-hidronaftaleno com HTIB em metanol foram formados os produtos de adição (cis e trans-1,2-dimetoxi-1,2,3,4-tetrahidro-1-metil-naftaleno) em ótimos rendimentos. / This dissertation presents a study about the ring contraction of ß,y-unsaturated esters promoted by thallium trinitrate (TTN) and 1,2-dihydronaphthalenes promoted by hydroxy(tosyloxy)iodobenzene (HTIB). Both studies aimed the synthesis of functionalizated indans. The reaction of a series of ß,y-unsaturad esters with TTN in acetic acid led to the corresponding ring contraction products, giving indans in good yields. The presence of electron donating groups in the 6-position of the aromatic ring increases the yield of the ring contraction product. On the other hand, electron withdrawing groups in the 7-position of the aromatic ring leds to a decrease of the yield of the desired product, when compared to substrates which are not substituted in this position. The increasement of the alkane chain at the alpha-carbonyl position did not interfere in the yield of the ring contraction product. The esters substituted by an alkyl group at 4-position of the ciclohexene ring leads to the ring contraction product, where the trans-1,3-disubstituted indan is the major product. The reaction of 1,2-dihydronaphthalene with HTIB in methanol gave the ring contraction product 1-dimetoxymethyl-indan with moderate yield, together with the addition products cis- and trans-1,2-dimetoxy-1,2,3,4-tetrahydronaphthalene. On the other hand, the reaction of 1,2-dihydronaphthalene with HTIB in acetonitrile, dichloro-methane or trimethyl orthoformate gave the aromatization product (naphthalene). The reaction of 4-methyl-1,2-dihydronaphthalene and 1,4-dimethyl-1,2-dihydronaphthalene with HTIB in acetonitrile leads to ring contraction products 1-indan-1-yl-ethanone and 1-(trans-3-methyl-indan-1-yl)-ethanone, respectively, in good yieds. The reaction of 4-methyl-1,2-dihydronaphthalene with HTIB in methanol gave the addition products cis- and trans-1,2-dimetoxy-1,2,3,4-tetrahydro-1-methyl-naphthalene) with very good yield.
5

Reações de ésteres ß,Y-insaturados com tálio(III) e de 1,2-di-hidronaftalenos com iodo(III) / Reactions of ß,Y-unsaturated esters with thallium(III) and 1,2-dihydronaphthalenes with iodine(III)

Eliane Corrêa Pedrozo 30 August 2006 (has links)
Esta dissertação apresenta um estudo sobre a contração de anel de ésteres ß,y-insaturados promovida por trinitrato de tálio (TTN) e de 1,2-di-hidronaftalenos promovida por hidroxi(tosiloxi)iodobenzeno (HTIB), também conhecido como reagente de Koser. Ambos estudos visaram à síntese de indanos funcionalizados. A reação de uma série de ésteres ß,y-insaturados (por exemplo 2-(3,4-di-hidronaftalen-1-il)-proprionato de etila) com TTN em ácido acético forneceu os correspondentes produtos de contração, formando indanos em bons rendimentos. A presença de grupos doadores de elétrons na posição 6 no anel aromático resultou no aumento do rendimento do produto de contração, enquanto que grupos atraentes de elétrons na posição 7 do anel aromático acarretou o decréscimo do rendimento do indano quando comparado a substratos que não são substituídos nesta posição. O aumento da cadeia alquílica na posição alfa-carbonila não interferiu no rendimento do produto desejado. O éster substituído por uma metila na posição 4 do anel ciclo-hexênico levou preferencialmente ao indano trans-1,3-dissubstituído. A reação do 1,2-di-hidronaftaleno com HTIB em metanol levou ao produto de contração de anel 1-dimetoximetil-indano com rendimento moderado, além dos produtos de adição cis e trans-1,2-dimetoxi-1,2,3,4-tetra-hidronaftaleno. No entanto, a reação desse substrato com HTIB em acetonitrila, diclorometano ou trimetil-ortoformiato forneceu o produto de aromatização (naftaleno). Contudo, os produtos de contração, 1-indano-1-il-etanona e 1-(3-metil-indan-1-il)-etanona foram formados em bons rendimentos quando o 4-metil-1,2-di-hidronaftaleno e o 1,4-dimetil-1,2-di-hidronaftaleno, respectivamente, foram tratados com HTIB em acetonitrila. No caso do 1,4-dimetil-1,2-di-hidronaftaleno há uma predominância na formação do isômero trans. Finalmente, para a reação de 4-metil-1,2-di-hidronaftaleno com HTIB em metanol foram formados os produtos de adição (cis e trans-1,2-dimetoxi-1,2,3,4-tetrahidro-1-metil-naftaleno) em ótimos rendimentos. / This dissertation presents a study about the ring contraction of ß,y-unsaturated esters promoted by thallium trinitrate (TTN) and 1,2-dihydronaphthalenes promoted by hydroxy(tosyloxy)iodobenzene (HTIB). Both studies aimed the synthesis of functionalizated indans. The reaction of a series of ß,y-unsaturad esters with TTN in acetic acid led to the corresponding ring contraction products, giving indans in good yields. The presence of electron donating groups in the 6-position of the aromatic ring increases the yield of the ring contraction product. On the other hand, electron withdrawing groups in the 7-position of the aromatic ring leds to a decrease of the yield of the desired product, when compared to substrates which are not substituted in this position. The increasement of the alkane chain at the alpha-carbonyl position did not interfere in the yield of the ring contraction product. The esters substituted by an alkyl group at 4-position of the ciclohexene ring leads to the ring contraction product, where the trans-1,3-disubstituted indan is the major product. The reaction of 1,2-dihydronaphthalene with HTIB in methanol gave the ring contraction product 1-dimetoxymethyl-indan with moderate yield, together with the addition products cis- and trans-1,2-dimetoxy-1,2,3,4-tetrahydronaphthalene. On the other hand, the reaction of 1,2-dihydronaphthalene with HTIB in acetonitrile, dichloro-methane or trimethyl orthoformate gave the aromatization product (naphthalene). The reaction of 4-methyl-1,2-dihydronaphthalene and 1,4-dimethyl-1,2-dihydronaphthalene with HTIB in acetonitrile leads to ring contraction products 1-indan-1-yl-ethanone and 1-(trans-3-methyl-indan-1-yl)-ethanone, respectively, in good yieds. The reaction of 4-methyl-1,2-dihydronaphthalene with HTIB in methanol gave the addition products cis- and trans-1,2-dimetoxy-1,2,3,4-tetrahydro-1-methyl-naphthalene) with very good yield.

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