Thesis (Ph. D.)--University of Wisconsin--Madison, 1955. / Typescript. Abstracted in Dissertation abstracts, v. 15 (1955) no. 12, p. 2417. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 157-161).

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Thesis (Ph. D.)--Catholic University of America, 1942. / Reproduced from type-written copy. "Literature cited": p. 41-43.

Thesis (Ph. D.)--University of Chicago, 1938. / Reproduced from type-written copy. "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois." eContent provider-neutral record in process. Description based on print version record. Bibliographical foot-notes.

Thesis (Ph. D.)--University of Chicago, 1938. / Reproduced from type-written copy. "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois." eContent provider-neutral record in process. Description based on print version record. Bibliographical foot-notes.

Orientador: Ulf Friedrich Schuchardt / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-06T15:18:09Z (GMT). No. of bitstreams: 1 Lima_LilianeSchierde_M.pdf: 699085 bytes, checksum: 864f8f983b1935cceb9fe8d839e3fcf4 (MD5) Previous issue date: 2006 / Resumo: O interesse nas reações de oxidação do cicloexano e cicloexeno tem sido foco de muitas pesquisas nos últimos anos, objetivando a busca de reações com maiores rendimentos e seletividades. A rota sintética comercialmente utilizada oxida o cicloexano a cicloexanol e cicloexanona com rendimentos muito baixos (em torno de 4 %), fomentando ainda mais a busca por rotas alternativas de oxidação. O presente trabalho estudou a oxidação direta de cicloexano e cicloexeno a 140ºC e pressões de até 50 bar usando carvões ativados de origem mineral e vegetal como catalisadores. O carvão ativado, por se tratar de um material com uma alta área superficial e de característica hidrofóbica, é compatível com reações de hidrocarbonetos e, então, foi utilizado como catalisador para estas oxidações. As oxidações diretas do cicloexano, nas condições em que foram realizadas, apresentaram resultados de conversão abaixo de 1% e, em alguns casos, com resultados irreprodutíveis. Para as reações de oxidação do cicloexeno, além de algumas mudanças nas condições das reações, foram utilizados como catalisadores carvão ativado impregnados com Pd. As reações apresentaram boas conversões, que variaram de 5 a 90%. Os carvões minerais previamente tratados com ácido clorídrico conduziram a melhores resultados nas oxidações catalíticas do cicloexeno, porém um comportamento inverso foi observado para os carvões vegetais. O Pd impregnado favoreceu a formação da bifenila, alcançando 100% de seletividade para este produto quando usou-se um carvão comercial contendo 5% de Pd. / Abstract: The concerning about cyclohexane and cyclohexene oxidation reactions has been subject of many researches lately, in order to find yielder and more selective reactions. The more common synthetic path at the industry, oxidate the cyclohexane to cyclohexanol and cyclohexanone with very low yield (almost 4%), what stimulates the researches looking for alternatives oxidations paths. The present work has studied the straight oxidation from the cyclohexane and cyclohexene in a temperature of 140°C and pressures until 50 bars using activated carbon, mineral and vegetal origins, as a catalyser. Due the activated carbon is a material with very high surface area and it has also hydrophobic characteristics, it is compatible with hydrocarbons reactions, and then it has been used here as catalyser to this oxidations. The straight cyclohexane oxidations, in that conditions, has showed conversion results lower than 1% and, in some cases, with non reproducible results. To the cyclohexene oxidation reactions, besides some changes in the reactions conditions, it has been used as a catalyser, activated carbon impregnated with Pd. Those reactions showed better conversions, between 5% and 90%. The mineral carbons, previously treated with chloride acid, lead to better results in the catalytic oxidation of the cyclohexene, although an inverse behavior has been observed to the vegetal carbons. The Pd impregnation has helped the biphenyl production, reaching 100% selectivity to this product when using a carbon containing 5% of Pd. / Mestrado / Quimica Organica / Mestre em Química

Orientador: Antonio Jose Gomez Cobo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-15T16:04:26Z (GMT). No. of bitstreams: 1 Suppino_RaphaelSoeiro_M.pdf: 3682407 bytes, checksum: 9e1b8ac86459e6d0a450f3e0aaea6013 (MD5) Previous issue date: 2010 / Resumo: A reação de hidrogenação parcial do benzeno em fase líquida tem sido estudada com vistas à obtenção do cicloexeno. Este produto de alto valor agregado pode ser utilizado para a obtenção de poliamidas, como o nylon, através de uma rota industrialmente simples e ecologicamente correta. Esta reação possui ainda uma importante aplicação na proteção ambiental, face às severas restrições à presença de compostos aromáticos nos combustíveis. O presente trabalho tem por objetivo estudar o desempenho de catalisadores de Ru/Al2O3 e Ru/CeO2 preparados através dos métodos de impregnação incipiente e impregnação úmida. Objetiva-se ainda estudar os efeitos da adição de solventes orgânicos ao meio reacional, e a utilização dos solventes na separação dos produtos da reação. Os catalisadores estudados foram preparados a partir de soluções aquosas de RuCl3.xH2O. No caso da impregnação incipiente, os sólidos foram secos a 358 K por 24 h e reduzidos sob fluxo de H2 a 573 K por 3 h. No caso da impregnação úmida, os catalisadores foram reduzidos com formaldeído a 353 K, durante a impregnação. Os suportes Al2O3 e CeO2 foram caracterizados através de titulação potenciométrica e a adsorção de N2 (método de B.E.T.) foi empregada para determinar a área específica dos sólidos. As técnicas de MEV+EDX e XPS permitiram avaliar a composição dos sólidos, enquanto que a formação da fase ativa dos catalisadores foi estudada através de TPR. O desempenho dos catalisadores foi avaliado na reação de hidrogenação parcial do benzeno em fase líquida, conduzida à pressão constante de 5 MPa de H2 e a 373 K num reator Parr do tipo slurry. A destilação extrativa dos produtos de reação foi estudada com o software Aspen Plus®. Os resultados obtidos indicam que os catalisadores de Ru/Al2O3, preparados por impregnação úmida, apresentam os melhores desempenhos catalíticos nesta reação. O rendimento de cicloexeno aumenta com a adição de solvente ao meio reacional, segundo a ordem: monoetanolamina > monoetilenoglicol > n-metil-2-pirrolidona > acetato de etila. Nas condições deste estudo o monoetilenoglicol foi o único solvente capaz de separar todos os produtos de reação com eficiência suficiente para um processo industrial / Abstract: The reaction of partial hydrogenation of benzene in liquid phase has been studied with the purpose of obtaining cyclohexene. This product of high aggregated value can be used to obtain polyamides such as nylon, through a route industrially simple and environmentally friendly. This reaction also has an important application in environmental protection, given the severe restrictions on the presence of aromatics in fuels. In this context, this work aims to study the performance of Ru/Al2O3 and Ru/CeO2 catalysts prepared by the methods of incipient impregnation and wet impregnation. Another object of the present work is to study the effects of adding organic solvents to the reaction medium, and the use of these solvents for the separation of reaction products. The catalysts were prepared from aqueous solutions of RuCl3. xH2O. In the case of incipient impregnation, the solids were dried at 358 K for 24 h and reduced under H2 flow at 573 K for 3 h. In the case of wet impregnation, the catalysts were reduced with formaldehyde at 353 K during the impregnation step. The supports Al2O3 and CeO2 were characterized by potentiometric titration and N2 adsorption (B.E.T. method) was used to determine the specific area of the solids. The techniques of SEM + EDX and XPS allowed the evaluation of the composition of solids, whereas the formation of the active phase of catalysts was studied by TPR. The performance of the catalysts was evaluated in the liquidphase partial hydrogenation of benzene carried out at H2 constant pressure of 5 MPa and 373 K in a slurry Parr reactor. The extractive distillation of the reaction products was studied with the software Aspen Plus ®. The results indicate that the catalysts Ru/Al2O3, prepared by wet impregnation, led to the best performances observed for this reaction. The yield of cyclohexene increases with the addition of solvent to the reaction medium, following the order: monoethanolamine > monoethylene glycol > n-methyl-2-pyrrolidone > ethyl acetate. In this study, monoethylene glycol was the only solvent able to efficiently separate all reaction products to obtain cyclohexene in an industrial process / Mestrado / Sistemas de Processos Quimicos e Informatica / Mestre em Engenharia Química

Este trabalho compreende a síntese e caracterização de um novo catalisador magneticamente recuperável de CoO para oxidação alílica de alcenos. O catalisador foi preparado através da deposição de nanopartículas (de tamanho entre 2-3 nm) do metal cataliticamente ativo em nanopartículas de magnetita revestidas por sílica. A natureza magnética do suporte permitiu a fácil separação do catalisador do meio reacional após o termino das reações pela simples aproximação de um ímã na parede do reator. O catalisador pôde ser completamente separado da fase líquida, fazendo com que a utilização de outros métodos de separação como filtração e centrifugação, comumente utilizados em sistemas heterogêneos líquidos, fossem completamente dispensados. O catalisador foi inicialmente testado em reações de oxidação do substrato modelo cicloexeno e mostrou seletividade para a produção do produto alílico, cicloex-2-en-1-ona, que é reagente de partida de grande interesse para a síntese de diversos materiais na indústria química. As reações de oxidação foram realizadas utilizando-se apenas O2 como oxidante primário, dispensando o uso de oxidantes tóxicos como cromatos ou permanganatos, que não são recomendados do ponto de vista ambiental. O catalisador sintetizado mostrou ser reutilizável em sucessivos ciclos de oxidação, destacando-se o aumento da seletividade para a formação da cetona alílica conforme o catalisador perde atividade. A lixiviação da espécie ativa para o meio reacional, problema comum na catálise heterogênea, não foi observada. Um estudo cinético mostrou que mesmo no inicio da reação o catalisador tem seletividade para a ocorrência de oxidação alílica em detrimento da reação de oxidação direta que dá origem ao produto epóxido. Em todos os tempos estudados o produto principal da reação foi sempre a cicloexenona. Os estudos também revelaram que CoO é a espécie mais ativa quando comparado com Co2+, Co3O4 e Fe3O4 nas mesmas condições reacionais. O catalisador de CoO foi empregado na oxidação de monoterpenos mostrando alta seletividade para a formação dos produtos alílicos, resultando em derivados oxigenados altamente valiosos para a indústria de fragrâncias. / This master thesis describes the synthesis and characterization of a magnetically recoverable CoO catalyst for allylic oxidation of alkenes. The catalyst was prepared through the deposition of the catalytic active metal nanoparticles of 2-3 nm on silica-coated magnetite nanoparticles. The magnetic nature of the support allowed the easy separation of catalyst from the reaction medium after the completion of the reaction by simply placing a magnet on the reactor wall.The magnetic separation technique used was able to completely isolate the solid from the liquid phase, making the use of other separation methods such as filtration and centrifugation, commonly used in liquid heterogeneous systems, unnecessary.The catalyst was initially tested in the oxidation of cyclohexene, as a model substrate, and showed high selectivity to the formation of the allylic product, cyclohex-2-en-1-one, an interesting starting reactant for many reactions in the chemical industry. The oxidation reactions were performed using O2 as primary oxidant, eliminating the use of toxic oxidants such as chromate or permanganate, which are not environmentally friendly. The synthesized catalyst was found to be reusable in successive runs, with the increasing selectivity to the allylic ketone as the catalyst lost its activity. The leaching of active species to the reaction medium, a common problem in heterogeneous catalysis, was not observed. A kinetic study showed that even at initial times the catalyst is selective for the allylic oxidation despite the direct oxidation, which leads to the formation of the epoxy product. For all reactions studied in different times, the product was always cyclohexenone. The studies also revealed that CoO is the most active species when compared to Co2+, Co3O4 and Fe3O4 in the catalytic conditions studied. The CoO catalyst was used in the oxidation of monoterpenes and showed high selectivity for the allylic products, giving oxygenate derivatives of highly value for flagrance industry.

Este trabalho compreende a síntese e caracterização de um novo catalisador magneticamente recuperável de CoO para oxidação alílica de alcenos. O catalisador foi preparado através da deposição de nanopartículas (de tamanho entre 2-3 nm) do metal cataliticamente ativo em nanopartículas de magnetita revestidas por sílica. A natureza magnética do suporte permitiu a fácil separação do catalisador do meio reacional após o termino das reações pela simples aproximação de um ímã na parede do reator. O catalisador pôde ser completamente separado da fase líquida, fazendo com que a utilização de outros métodos de separação como filtração e centrifugação, comumente utilizados em sistemas heterogêneos líquidos, fossem completamente dispensados. O catalisador foi inicialmente testado em reações de oxidação do substrato modelo cicloexeno e mostrou seletividade para a produção do produto alílico, cicloex-2-en-1-ona, que é reagente de partida de grande interesse para a síntese de diversos materiais na indústria química. As reações de oxidação foram realizadas utilizando-se apenas O2 como oxidante primário, dispensando o uso de oxidantes tóxicos como cromatos ou permanganatos, que não são recomendados do ponto de vista ambiental. O catalisador sintetizado mostrou ser reutilizável em sucessivos ciclos de oxidação, destacando-se o aumento da seletividade para a formação da cetona alílica conforme o catalisador perde atividade. A lixiviação da espécie ativa para o meio reacional, problema comum na catálise heterogênea, não foi observada. Um estudo cinético mostrou que mesmo no inicio da reação o catalisador tem seletividade para a ocorrência de oxidação alílica em detrimento da reação de oxidação direta que dá origem ao produto epóxido. Em todos os tempos estudados o produto principal da reação foi sempre a cicloexenona. Os estudos também revelaram que CoO é a espécie mais ativa quando comparado com Co2+, Co3O4 e Fe3O4 nas mesmas condições reacionais. O catalisador de CoO foi empregado na oxidação de monoterpenos mostrando alta seletividade para a formação dos produtos alílicos, resultando em derivados oxigenados altamente valiosos para a indústria de fragrâncias. / This master thesis describes the synthesis and characterization of a magnetically recoverable CoO catalyst for allylic oxidation of alkenes. The catalyst was prepared through the deposition of the catalytic active metal nanoparticles of 2-3 nm on silica-coated magnetite nanoparticles. The magnetic nature of the support allowed the easy separation of catalyst from the reaction medium after the completion of the reaction by simply placing a magnet on the reactor wall.The magnetic separation technique used was able to completely isolate the solid from the liquid phase, making the use of other separation methods such as filtration and centrifugation, commonly used in liquid heterogeneous systems, unnecessary.The catalyst was initially tested in the oxidation of cyclohexene, as a model substrate, and showed high selectivity to the formation of the allylic product, cyclohex-2-en-1-one, an interesting starting reactant for many reactions in the chemical industry. The oxidation reactions were performed using O2 as primary oxidant, eliminating the use of toxic oxidants such as chromate or permanganate, which are not environmentally friendly. The synthesized catalyst was found to be reusable in successive runs, with the increasing selectivity to the allylic ketone as the catalyst lost its activity. The leaching of active species to the reaction medium, a common problem in heterogeneous catalysis, was not observed. A kinetic study showed that even at initial times the catalyst is selective for the allylic oxidation despite the direct oxidation, which leads to the formation of the epoxy product. For all reactions studied in different times, the product was always cyclohexenone. The studies also revealed that CoO is the most active species when compared to Co2+, Co3O4 and Fe3O4 in the catalytic conditions studied. The CoO catalyst was used in the oxidation of monoterpenes and showed high selectivity for the allylic products, giving oxygenate derivatives of highly value for flagrance industry.

Abstract: A brief overview of this PhD thesis, The emergence of nanotechnology has stimulated both fundamental and industrially relevant studies of the catalytic activity of noble metal nanoparticles. Palladium, ruthenium and gold are well known catalysts when used in nanoparticle- based systems. This body of work endeavoured to investigate the catalytic activity of these noble metal nanoparticles through three studies as a briefly overviewed below. Study 1: Palladium is a well-known catalyst, even in bulk phases, but its high cost had driven industry towards its use in nanoparticle- based systems well before nanotechnology had attracted the attention of the media. Palladium nanoparticles often show remarkable catalytic activity and selectivity, particularly for the hydrogenation of some unsaturated hydrocarbons, such as alkenes, alkynes and unsaturated carbonyl compounds. The nature of supports can affect the catalytic activity and selectivity of metal-support interaction. Natural polymeric supports, such as wool, can be suitable for new generation of composite materials incorporating nanosized metal nanoparticles and have the added advantage of being “environmentally friendly”. Catalytic hydrogenation of cyclohexene to cyclohexane by palladium nanoparticles immobilized on wool was demonstrated by using a Parr high pressure hydrogenation set-up. The efficiency of the process was explored over loading rates from 1.6% to 2.6% of palladium nanoparticles (by weight) with a variety of particle sizes. Optimization of the reaction conditions including, stirring rate, amounts of reactants, gas pressure and target temperature, led to series of catalytic activity tests carried out for 5 or 24 hours (each) at 400psi H2 and 40 oC using a stirring rate 750 rpm. Product mixtures were analysed using gas chromatography (GC-FID) to determine conversions. Samples S1 and S2 proved to be the most active catalysts because the average Pd particle size was around ~5 nm and the particles were more accessible for the reactant (i.e., Pd particles were on the surface of wool). However, under the catalytic testing conditions studied, wool (Pd/wool) did not show advantages over commercially used palladium nanoparticles on activated carbon (Pd/C). Study 2: Ruthenium fabricated as noble metal nanoparticles can be catalytically active for hydrogenation of organic compounds. However, a challenging issue for researchers is that Ru nanocatalysts can be spontaneously deactivated due to effects, such as sintering or leaching of active components, oxidation of noble metal nanoparticles, inactive metal or metal oxide deposition and impurities in solvents and reagents. Calcination of noble metal nanoparticles is one option for reactivation of Ru nanoparticles immobilized on SiO2 (Ru/SiO2) utilized as nanocatalysts in chemical reactions. In fact, the catalytic activity of noble metal nanoparticles is known to be proportional to the active part of the surface area. The effects of calcinations on catalytic activity of “shape- specific” 0.1 wt% Ru/SiO2 for hydrogenation of cyclohexene to cyclohexane were investigated. Optimization of calcinations by varying temperature and time proved to be effective on the activity of nanocatalysts retaining the Ru nanocatalysts shapes for the hydrogenation of cyclohexene. Product mixtures were analysed using gas chromatography (GC-FID) to determine conversions. The Ru catalysts showed the highest activity (100%) when they were activated by calcination following protocol No.1 in a furnace under the mildest reductive conditions studied (temperature = 200 oC for 1 hour, which was the shortest calcination time). HRTEM study showed only minor deformation of the Ru nanoparticles and minimal aggregation for this type of activation. Study 3: Supported gold nanoparticles have excited much interest owing to their unusual and somewhat unexpected catalytic activity particularly with the selective oxidation of organic compounds. Gold nanoparticles immobilized on Norit activated carbon (Au101/C) via colloidal deposition gave high selectivity of benzyl alcohol oxidation. The presence of a base (K2CO3) increased the catalytic activity of gold nanocatalysts (which was negligible in the absence of base) through dehydrogenation of the alcohol via deprotonation of a primary OH groups, and helped overcome the rate-limitation step of the oxidation process. The interaction between the gold species and the support was investigated by measuring change in catalytic activity with different activation methods (i.e., washing with a solvent at elevated temperature, and/or followed by calcinations). A mixture of benzyl alcohol as a reactant, methanol as a solvent, K2CO3 as a base and oxygen gas was studied by the activated gold nanocatalysts using a mini reactor set-up. The efficiency of the process was explored by varying the amounts of benzyl alcohol and the base, target temperature, metal loading of the gold catalysts rate and the solvent, between 3 and 24 hours at 73 psi O2 and a stirring rate (750 rpm). The samples of the reaction mixture were centrifuged and analysed by highperformance liquid chromatography (HPLC) to determine conversions. The effect of size on the catalytic activity was studied for different types of gold particles (Au101, Aunaked and Aucitrate) and clusters (Au8 and Au9) immobilized on powder Norit activated carbon. The highest activity of benzyl alcohol oxidation was observed for activated 1.0 wt% Au101/C catalysts (washed with toluene and followed by calcination under vacuum at 100 oC for 3 h) for ~3.5 nm gold particles. Additionally, the support effect was studied for gold particles immobilized on different types of carbons, such as Norit activated carbon (powder, granular and powdered) and mesoporous carbons (CMK-3, CMK-8 and NCCR-41), granular modified carbon (–SH and –SO3H groups) and Vulcan carbon. The highest activity was observed by activated 1.0 wt% Au101/C8 catalysts (washed with toluene and followed by calcination under vacuum at 100 oC for 3 h). Activated 1% Au101/C41 (washed with toluene followed by calcination under vacuum at 100 oC for 3 hours) with 2.6 ± 0.1 nm gold particle size showed the highest selectivity towards methyl benzoate as a main product (S%: 88%) after 3 hours reaction time. However, activated 1% Au101/C (calcination in O2 -H2 at 100 oC for 3 hours) with 6.6 ± 0.3 nm gold particle size exhibited the highest selectivity towards benzoic acid as a main product (S: 86%) after 24 hours reaction time.Therefore, particle size and type of carbon support can be considered as playing crucial roles in defining the catalytic activity of gold nanocatalysts which were used for benzyl alcohol oxidation.