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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

Catalytic hydrogenation of an aromatic sulfonyl chloride into thiophenol

Rouckout, Nicolas Julien 15 May 2009 (has links)
The catalytic hydrogenation of an aromatic sulfonyl chloride was investigated in continuous and semi-batch mode processes using a Robinson-Mahoney stationary basket reactor. A complete experimental unit was designed and built. The operating and analytical procedures have been developed and the methodologies to gather the kinetic data have been described. Hydrogenation reactions were conducted at a reaction pressure of 364.7 psia, at three different reaction temperatures: 85 °C, 97 °C and 110 °C, at five different residence times: 0.6 (only at 110 °C), 1.0, 1.5, 2.0, 3.1 hr, with the hydrogen to the aromatic sulfonyl chloride molar ratio: 8.0 mol/mol and hydrogen to argon molar ratio: 3.0 mol/mol. Intrinsic reaction rates of the reacting species were obtained on the surface of a commercial 1 wt% palladium on charcoal catalyst. The conversion and molar yield profiles of the reacting species with respect to process time suggest a deactivation of the 1 wt % palladium on charcoal catalyst. Kinetic data collected in a continuous process mode show that the catalyst is deactivated during an experiment when the process time equal to two to three times the residence time of the liquid within the reactor. XRD analysis shows that the active sites are blocked and an amorphous layer was formed on the surface of the palladium catalyst. Semi-Batch mode experimental data were obtained at 110 °C after 8 hours of reaction time for several aromatic sulfonyl chlorides. A kinetic model has been developed, which includes adsorption of individual components and surface reactions as well as rate equations of the Hougen-Watson type. A hyperbolic deactivation function expressed in term of process time is implemented in the Hougen-Watson equation rates. The mathematical model consists of non-linear and simultaneous differential equations with multiple variables. The kinetic parameters were estimated from the minimization of a multi-response objective function by means of a sequential quadratic program, which includes a quasi-Newton algorithm. The statistical analysis was based on the t- and F-tests and the simulated results were compared to the experimental data.
2

Chemical Derivatization in Combination with Liquid Chromatography Tandem Mass Spectrometry for Detection and Structural Investigation of Glucuronides

Lampinen Salomonsson, Matilda January 2008 (has links)
<p>This thesis presents novel approaches for structural investigation of glucuronides using chemical derivatization in combination with liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS<sup>n</sup>).</p><p>Today, LC-ESI-MS<sup>n</sup> is the dominant technique for quantitative as well as qualitative analyses of metabolites, due to its high sensitivity and selectivity. However, for compounds without an easily ionizable group, e.g., steroids, the sensitivity is limited. In the work presented in this thesis, a derivatization procedure forming a basic oxime significantly increased the detection sensitivity for the altrenogest glucuronide. </p><p>Furthermore, in structural evaluations of glucuronides, the limitation of LC-MS<sup>n</sup> becomes evident due to the initial neutral loss of 176 u, i.e. monodehydrated glucuronic acid, which often makes it impossible to elucidate the structures of the conjugates. To solve this problem, the main part of the work described in this thesis was devoted to chemical derivatization as a means of facilitating the determination of the site of conjugation. </p><p>For the first time, the isomeric estriol glucuronides were evaluated using a combination of three reagents 2-chloro-1-methylpyridinium iodide (CMPI), 1-ethyl-3-(3-dimethyl- aminopropyl)-carbodiimide (EDC), and 2-picolylamine (PA). Interestingly, the derivatization gave a selective fragmentation pattern leading to differentiation of the isomers. </p><p>Another derivatization reagent, 1,2-dimethylimidazole-4-sulfonyl chloride (DMISC), was also tested for the first time in structural investigations. The isomeric glucuronides of morphine, formoterol, and hydroxypropranolol were evaluated. They can all be conjugated in aliphatic as well as aromatic positions. DMISC was proven to be useful in two ways. Firstly, the morphine and formoterol glucuronides that contained a free phenol could be differentiated from those that were conjugated in the aromatic position based on different reactivity. Secondly, for the aromatic <i>O</i>-glucuronide of 4’-hydroxypropranolol, DMISC was proven to react with the amine. This product gave a different fragmentation pattern compared to the corresponding derivative of the aliphatic glucuronide. </p>
3

Chemical Derivatization in Combination with Liquid Chromatography Tandem Mass Spectrometry for Detection and Structural Investigation of Glucuronides

Lampinen Salomonsson, Matilda January 2008 (has links)
This thesis presents novel approaches for structural investigation of glucuronides using chemical derivatization in combination with liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MSn). Today, LC-ESI-MSn is the dominant technique for quantitative as well as qualitative analyses of metabolites, due to its high sensitivity and selectivity. However, for compounds without an easily ionizable group, e.g., steroids, the sensitivity is limited. In the work presented in this thesis, a derivatization procedure forming a basic oxime significantly increased the detection sensitivity for the altrenogest glucuronide. Furthermore, in structural evaluations of glucuronides, the limitation of LC-MSn becomes evident due to the initial neutral loss of 176 u, i.e. monodehydrated glucuronic acid, which often makes it impossible to elucidate the structures of the conjugates. To solve this problem, the main part of the work described in this thesis was devoted to chemical derivatization as a means of facilitating the determination of the site of conjugation. For the first time, the isomeric estriol glucuronides were evaluated using a combination of three reagents 2-chloro-1-methylpyridinium iodide (CMPI), 1-ethyl-3-(3-dimethyl- aminopropyl)-carbodiimide (EDC), and 2-picolylamine (PA). Interestingly, the derivatization gave a selective fragmentation pattern leading to differentiation of the isomers. Another derivatization reagent, 1,2-dimethylimidazole-4-sulfonyl chloride (DMISC), was also tested for the first time in structural investigations. The isomeric glucuronides of morphine, formoterol, and hydroxypropranolol were evaluated. They can all be conjugated in aliphatic as well as aromatic positions. DMISC was proven to be useful in two ways. Firstly, the morphine and formoterol glucuronides that contained a free phenol could be differentiated from those that were conjugated in the aromatic position based on different reactivity. Secondly, for the aromatic O-glucuronide of 4’-hydroxypropranolol, DMISC was proven to react with the amine. This product gave a different fragmentation pattern compared to the corresponding derivative of the aliphatic glucuronide.

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