Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 4 uppsatser.

No description available.

A couple of processes for electrosynthetic production of expendable reagents, namely acids, bases, and oxidants, from the native salt content of raw waters and industrial wastes were investigated, and the composition of mixed acids and bases made of sodium sulfate or sodium chloride salts were predicted using a model predicated on conservation principles, mass action relations, and Pitzer equations. Electrodialysis with bipolar membranes (BMED) was used to produce acids and bases in a single pass. Product concentration was limited only by the salt content of the feed water. The current efficiency for acid production was slightly higher than that for base, but neither dropped below 75%. Acid and base current utilization showed the same trends with respect to feed salt content and flow velocity, with higher efficiency at higher feed salt concentrations and flow velocities. Operating the BMED stack near the limiting current density of the bipolar membrane (BLCD) or above the limiting current density of the diluate compartment (LCD) decreased current efficiency and increased electrical power dissipation. Electrodialytic acid and base production was approximately10 times cheaper than the chemicals' f.o.b. unit costs as quoted on Alibaba.com. The mechanism and cost of on site peroxodisulfuric acid production by electrolysis of sulfuric acid solutions with boron doped diamond film anodes was investigated experimentally and with molecular dynamics (MD) and density functional theory (DFT) simulations. The cost of on site peroxodisulfate production was approximately 4 times less expensive than purchasing a 25 lb bag. It was shown that direct discharge of sulfate species produces sulfate radicals, which subsequently combined to form peroxodisulfuric acid. The likely hood of these reactions was dependent on electrode surface condition. Sulfate radicals could also be produced in solution by reaction with hydroxyl radicals generated by water discharge.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Thesis (Ph. D.)--University of Virginia, 2009. / Title from title page. Includes bibliographical references. Also available online through Digital Dissertations.

This dissertation covers the studies of two major topics: the photochemistry of mononuclear and multinuclear gold(I) complexes and synthetic approaches to tailor photophysical properties of cyclic trinuclear d10 complexes. First a detailed photochemical examination into the photoreactivity of neutral mononuclear and multinuclear gold(I) complexes is discussed, with the aim of gold nanoparticle size and shape control for biomedical and catalysis applications. Next is a comprehensive systematic synthetic approach to tailor the photophysical properties of cyclic trinuclear d10 complexes. This synthetic approach includes an investigation of structure-luminescence relationships between cyclic trinuclear complexes, an examination into their π-acid/π-base reactivity with heavy metal cations and an exploration into the photophysical properties of new heterobimetallic cyclic trinuclear complexes. These photophysical properties inspections are used to screen materials for their employment in molecular electronic devices such as organic light-emitting diodes (OLEDs) and thin film transistors (OTFTs).

A reação peroxioxalato é o sistema quimiluminescente não enzimático de maior eficiência, alcançando rendimentos quânticos de até 50%. A quimiluminescência deste sistema vem sendo amplamente utilizada em aplicações analíticas e bioanalíticas visando a detecção de analitos de interesses biológicos e medicinais. O presente trabalho consistiu em se estudar a reação peroxioxalato com diferentes catalisadores e determinação de seu mecanismo em condições experimentais distintas das que vinham sendo estudadas até o momento, visando sua adaptação a meios aquosos para futuras aplicações. Foi estudada a utilização do salicilato de sódio como catalisador deste sistema em meio puramente orgânico, em substituição ao imidazol, e verificou-se a atuação do salicilato como catalisador básico geral e/ou específico. O rendimento quântico máximo desta transformação foi da ordem de 10-3 E mol-1. Ensaios cinéticos de emissão também foram realizados com ésteres oxálicos de diferentes reatividades em um sistema binário composto por 1,2-dimetoxietano/água contendo tampão fosfato como catalisador, em diferentes valores de pH. Nestas condições se observou a ocorrência de catálise ácida geral e catálise básica geral, uma vez que as constantes de velocidade se mostraram dependentes da concentração de tampão no meio reacional. Além disso, também se utilizou salicilato de sódio como catalisador no sistema binário 1,2-dimetoxietano/água, o qual também apresentou um papel catalítico importante no percurso desta transformação com diferentes ésteres oxálicos. Verificou-se nestes estudos a boa reprodutibilidade da reação peroxioxalato com salicilato de sódio como catalisador em meios parcialmente aquosos, que pode ampliar a utilização deste sistema quimiluminescente em aplicações analíticas e bioanalíticas. Quando se realizou os ensaios em um meio majoritariamente aquoso, o salicilato não se mostrou um catalisador eficiente, porém, mesmo sem catalisador, a reação peroxioxalato se mostrou reprodutível nestas condições / The peroxyoxalate reaction is the non-enzymatic chemiluminescence system with the highest efficiency, achieving quantum yields of up to 50%. The chemiluminescence of this system has been widely used in analytical and bionanalytical applications in order to detect analytes of biological and medicinal interests. The present work consisted in a study of the peroxyoxalate reaction with different catalysts and the determination of its mechanism in experimental conditions different from those studied before, aiming its adaptation to aqueous media for future applications. The use of sodium salicylate as base catalyst for this system in pure organic medium, in substitution to imidazole, was studied and shown that salicylate acts as a general and/or specific base catalyst. The maximum quantum yield obtained for the transformation in these conditions was in the order of 10-3 E mol-1. Emission experiments were also performed in a binary solvent system composed of 1,2- dimethoxyethane/aqueous phosphate buffer at different pH values as catalyst, using oxalic esters with different reactivities. In these conditions the occurrence of general acid catalysis and general base catalysis was observed, since the rate constants proved to be dependent on the buffer concentration. In addition, sodium salicylate was also used as catalyst in the binary 1,2-dimethoxyethane/water system with different oxalic esters, indicating its important catalytic role in the transformation. These studies allowed it to establish a reproducible peroxyoxalate system in partially aqueous media using sodium salicylate as base catalyst, which may increase the use of the chemiluminescence of this system in analytical and bioanalytical applications. However, when the experiments were performed in a medium containing mostly water, salicylate did not act as an efficient catalyst in these conditions. Even in the absence of catalyst, the reaction proved to be reproducible in the medium containing mostly water as solvent

A reação peroxioxalato é o sistema quimiluminescente não enzimático de maior eficiência, alcançando rendimentos quânticos de até 50%. A quimiluminescência deste sistema vem sendo amplamente utilizada em aplicações analíticas e bioanalíticas visando a detecção de analitos de interesses biológicos e medicinais. O presente trabalho consistiu em se estudar a reação peroxioxalato com diferentes catalisadores e determinação de seu mecanismo em condições experimentais distintas das que vinham sendo estudadas até o momento, visando sua adaptação a meios aquosos para futuras aplicações. Foi estudada a utilização do salicilato de sódio como catalisador deste sistema em meio puramente orgânico, em substituição ao imidazol, e verificou-se a atuação do salicilato como catalisador básico geral e/ou específico. O rendimento quântico máximo desta transformação foi da ordem de 10-3 E mol-1. Ensaios cinéticos de emissão também foram realizados com ésteres oxálicos de diferentes reatividades em um sistema binário composto por 1,2-dimetoxietano/água contendo tampão fosfato como catalisador, em diferentes valores de pH. Nestas condições se observou a ocorrência de catálise ácida geral e catálise básica geral, uma vez que as constantes de velocidade se mostraram dependentes da concentração de tampão no meio reacional. Além disso, também se utilizou salicilato de sódio como catalisador no sistema binário 1,2-dimetoxietano/água, o qual também apresentou um papel catalítico importante no percurso desta transformação com diferentes ésteres oxálicos. Verificou-se nestes estudos a boa reprodutibilidade da reação peroxioxalato com salicilato de sódio como catalisador em meios parcialmente aquosos, que pode ampliar a utilização deste sistema quimiluminescente em aplicações analíticas e bioanalíticas. Quando se realizou os ensaios em um meio majoritariamente aquoso, o salicilato não se mostrou um catalisador eficiente, porém, mesmo sem catalisador, a reação peroxioxalato se mostrou reprodutível nestas condições / The peroxyoxalate reaction is the non-enzymatic chemiluminescence system with the highest efficiency, achieving quantum yields of up to 50%. The chemiluminescence of this system has been widely used in analytical and bionanalytical applications in order to detect analytes of biological and medicinal interests. The present work consisted in a study of the peroxyoxalate reaction with different catalysts and the determination of its mechanism in experimental conditions different from those studied before, aiming its adaptation to aqueous media for future applications. The use of sodium salicylate as base catalyst for this system in pure organic medium, in substitution to imidazole, was studied and shown that salicylate acts as a general and/or specific base catalyst. The maximum quantum yield obtained for the transformation in these conditions was in the order of 10-3 E mol-1. Emission experiments were also performed in a binary solvent system composed of 1,2- dimethoxyethane/aqueous phosphate buffer at different pH values as catalyst, using oxalic esters with different reactivities. In these conditions the occurrence of general acid catalysis and general base catalysis was observed, since the rate constants proved to be dependent on the buffer concentration. In addition, sodium salicylate was also used as catalyst in the binary 1,2-dimethoxyethane/water system with different oxalic esters, indicating its important catalytic role in the transformation. These studies allowed it to establish a reproducible peroxyoxalate system in partially aqueous media using sodium salicylate as base catalyst, which may increase the use of the chemiluminescence of this system in analytical and bioanalytical applications. However, when the experiments were performed in a medium containing mostly water, salicylate did not act as an efficient catalyst in these conditions. Even in the absence of catalyst, the reaction proved to be reproducible in the medium containing mostly water as solvent

Après avoir pu développer une nouvelle méthode de déracémisation de biphényles iodés permettant, pour la première fois, d’influencer la diastéréosélectivité de la réaction de piégeage du réactif d’Andersen par dédoublement cinétique, nous avons obtenu de nombreuses informations et développé des méthodes permettant de lever différents verrous synthétiques pour accéder à des paires de Lewis frustrées basées sur le squelette biphénylique et portant simultanément ou non un groupement acide de Lewis et une base de Lewis. Par la fonctionnalisation de ces biphényles, nous avons pu accéder à de nouvelles biphénylphosphines énantiopures pouvant jouer le rôle de base de Lewis dans le domaine des paires de Lewis frustrées (FLP) mais aussi d'organocatalyseur nucléophile ou de ligand pour la catalyse organométallique. Différentes méthodes ont ensuite été (re)développées, pour accéder à des acides de Lewis : d'une part la synthèse de boranes par fonctionnalisation de sels d'organotrifluoroborate de potassium comme précurseurs polyvalents d’acides de Lewis chiraux et énantiopurs et d'autre part l’utilisation de silanes électrophiles. L’ensemble des informations et méthodes découlant de ce travail pourront être appliquées à la synthèse de molécules ambiphiles, nouvelles paires de Lewis atropo-frustrées. / After having developed a new method of deracemization of iodinated biphenyls allowing us, for the first time, to influence the diastereoselectivity of the trapping by the Andersen reagent, we have turned our attention to the use of this molecular scaffold in the design of new frustrated Lewis pairs bearing either a Lewis acidic group, a Lewis basic group or simultaneously both groups. We first accessed a new series of enantiopure biphenylphosphines that can find applications as Lewis base (including the field of frustrated Lewis pairs), as nucleophilic organocatalyst or as ligand in organometallic catalysis. Then, various methods were (re)developed to access chiral biphenyl-based Lewis acids: firstly, the functionalization of biphenyltrifluoroborate salts as chiral and enantiopure borane precursors and secondly the use of electrophilic silanes. The whole information and methodologies developed herein may be applied to the synthesis of new ambiphilic compounds as new atropo-frustrated Lewis pairs.

This diploma thesis deals with acid-base and electrolytic behavior of hyaluronan solutions at different ionic strength. Acid-base behavior of hyaluronan was investigated by acid-base titrations which were carried out with two different methods, acid and alkaline acid-base titration. Dissociation constants at different ionic strength at zero degree of dissociation and at 50% degree of dissociation were evaluated from the results of acid-base titrations. Dissociation constants obtained from acid acid-base titrations have values between 3,0 and 3,6. Dissociation constants obtained from alkaline acid-base titrations are not very informative because their values are much higher than the expected values. The study of degradation of hyaluronan during acid-base titration was performed to complete study of acid-base behavior. Electrolytic behavior of hyaluronan solution was performed by conductometric titrations in three different environments.