No description available.

No description available.

No description available.

Thesis (Ph. D.)--University of Washington, 1992. / Vita. Includes bibliographical references (leaves [205]-215).

The purpose of this investigation was to obtain definite quantitative data on the optimum conditions for the production of ethylene oxide by the catalytic vapor phase oxidation of ethylene. This data was to cover the effects of temperature, ethylene concentration, and velocity of flow through the catalyst bed. The catalyst chosen was metallic silver, known to be effective in promoting the reaction. The experimental data obtained was to be used in making preliminary engineering studies on the design of a commercial plant for the production of ethylene glycol by first forming ethylene oxide and then hydrolyzing it to the glycol. The reactor used in oxidizing ethylene to the oxide consisted of an iron reactor tube 0.824 inches in diameter and 11.7 inches long, surrounded by a diphenylamine constant temperature bath. The tube was filled to a depth of 10 inches with the metallic silver catalyst. Rates of flow of the air and ethylene streams were controlled by means of needle valves and indicated by water filled manometers. The reactant gas mixture was pre-heated prior to passage through the reactor tube. A series of runs was made to determine the effect of ethylene concentration on the oxidation reaction. The temperature was held at approximately 260°C. and the gas flow rate was set at 25 liters/cm.²/hr. for each run. The ethylene concentration was varied from one per cent to 9.8 per cent. It was found that the highest yield of the oxide was obtained with an ethylene concentration of one per cent. An increase in the ethylene concentration was found to result in lower yields of the oxide. The effect on ethylene oxide production of the rate of gas flow through the catalyst bed was deter:nined by making three series of runs at gas flow rates of 12.5, 25 and 50 liters/cm²/hr. respectively. Temperatures were varied from 200°C. to 265°C., while the ethylene concentration was held at 2.2 per cent. It was found 2 that a rate of flow of 25 liters/cm. /hr. gave uniformly highest yields of ethylene oxide. A rate of flow of 50 liters/cm²/hr. gave the lowest yields, while a gas flow rate of 12.5 liters/cm²/hr. gave yields intermediate between the other two rates. The results of a series of runs made for the purpose of determining the effect of temperature on the yield of ethylene oxide indicated that the yield of oxide increased as the temperature was increased from 200°C. to 240°C. As the temperature was further increased from 240°C. to 265°C., the yield of ethylene oxide decreased with the increasing temperatures. The optimum temperature for the reaction was found to be 240°C. for gas flow rates of 12.5, 25 and 50 liters/cm²/hr. through the catalyst bed. The commercial plant, designed on the basis of the data obtained, is designed to produce 6,451,352 pounds of antifreeze mixture per year. The capital investment required is $3,900,054. The gross annual income would be $967,703 on the basis of a selling price of $0.15 per pound for the antifreeze mixture. The yearly cost of production would be $883,256, giving a net yearly income of $84,447. / M.S.

Thesis (Ph.D.)--University of Delaware, 2008. / Principal faculty advisor: Kristi L. Kiick, Dept. of Materials Science & Engineering. Includes bibliographical references.

An altered small intestinal permeability has been proposed as an important aetiological factor in the pathogenesis of inflammatory bowel disease. The relevant literature was reviewed. Intestinal permeability to Polyethylene glycol 400 in patients with Crohn' s disease, their relatives and healthy controls was examined and the data compared with studies of small bowel permeability to other similar sized probes. A new technique of analysis of urinary Polythylene Glycol 400 by High Performance Liquid Chromatography was described and compared with a previously established HPLC method. No evidence of an altered bowel permeability could be found using Polyethylene glycol 400, but the possibility that this may have been related to probe size and characteristics can not be excluded .

Thesis (Ph. D.)--Institute of Paper Chemistry, 1966. / Includes bibliographical references (p. 101-105).

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 157-172).

Orientador: Antonio José Gomez Cobo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-26T01:50:26Z (GMT). No. of bitstreams: 1 Queiroz_CarlaMoreiraSantos_M.pdf: 3283587 bytes, checksum: e066f63e41c49394fe6b4a9667355aab (MD5) Previous issue date: 2014 / Resumo: Com foco na sustentabilidade alinhada à obtenção de produtos de maior valor agregado, as indústrias químicas vêm investindo em pesquisas que viabilizem o processamento de matérias primas renováveis. Em particular, o sorbitol é um poliálcool proveniente da glicose, que pode ser convertido a etileno glicol e propileno glicol, derivados químicos de forte demanda industrial. Nesse contexto, o presente trabalho tem por objetivo estudar os efeitos dos suportes SiO2 kieselguhr, ?-Al2O3 e carvão ativado, assim como do método de impregnação, sobre o desempenho de catalisadores de Ru, destinados à hidrogenólise do sorbitol. Para tanto, catalisadores com uma fração mássica de 5 % de metal foram preparados através de impregnação incipiente ou úmida, a partir do precursor RuCl3.xH2O. Os sólidos preparados por impregnação incipiente foram submetidos a uma redução direta a 473 K (200 °C), sob fluxo de H2. A impregnação úmida foi realizada a 273 K (0 ºC), utilizando-se formaldeído como agente redutor. Suportes e catalisadores foram caracterizados através de técnicas para determinação da distribuição granulométrica, de titulação potenciométrica, adsorção de N2, porosimetria de Hg, microscopia eletrônica de varredura e redução à temperatura programada. Os desempenhos dos catalisadores foram avaliados na reação de hidrogenólise do sorbitol, conduzida em reatores trifásicos do tipo "slurry" e "trickle-bed". Durante os testes catalíticos, a temperatura e a pressão de H2 nos reatores foram mantidas constantes, entre 473 e 573 K (200 e 300 ºC) e entre 5 e 7 MPa (50 e 70 atm), respectivamente. Os resultados revelam que os catalisadores de Ru suportados em carvão ativado apresentam melhores desempenhos que aqueles suportados em SiO2 ou Al2O3. Maiores rendimentos de etileno glicol e propileno glicol são obtidos quando o catalisador de Ru/C é preparado por impregnação úmida / Abstract: Focusing on sustainability aligned to obtain products with higher added value, the chemical industries are investing in research that enables the processing of renewable raw materials. In particular, sorbitol is a polyalcohol derived from the glucose, which can be converted to ethylene glycol and propylene glycol, commodity chemical of strong industrial demand. In this context, the present work aims to study the supports effects SiO2 kieselguhr, ?-Al2O3 and activated carbon as well as the impregnation method on the performance of Ru catalysts for the hydrogenolysis of sorbitol. For this purpose, catalysts with a total fraction of 5 %wt. of metal were prepared by incipient or wet impregnation from the RuCl3.xH2O precursor. The solids prepared by incipient impregnation underwent direct reduction at 473 K (200 ° C) under flow H2. The wet impregnation was conducted at 273 K (0 ° C) using formaldehyde as reducing agent. Supports and catalysts were characterized by techniques for determination of particle size distribution, potentiometric titration, N2 adsorption, Hg porosimetry, scanning electron microscopy and temperature programmed reduction. The performances of the catalysts were evaluated though the sorbitol hydrogenolysis reaction, conducted in three phase reactors such as "slurry" and "trickle-bed". During the catalytic tests the temperature and H2 pressure in the reactors were kept constant between 473 and 573 K (200 to 300 ° C) and between 5 and 7 MPa (50 to 70 atm), respectively. The results indicate that the Ru catalysts supported on activated carbon have better performance than those supported on SiO2 or Al2O3. Higher yields of ethylene glycol and propylene glycol are obtained when the catalyst Ru/C is prepared by wet impregnation / Mestrado / Sistemas de Processos Quimicos e Informatica / Mestra em Engenharia Química