Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 198-215). Also available on the Internet.

The catalytic effects of selected iron phases (metal, oxides, sulfides, and carbides) on the Boudouard reaction (2 CO = CO₂ + C) were studied, in an effort to more fully understand the disintegration of refractories when exposed to CO for long periods of time. Based on computer generated equilibrium phase maps (SOLGASMIX program), experimental kinetic data including activation energies and x-ray diffraction data of iron phases, the following conclusions were reached: (1) Ferric oxide (Fe₂O₃ ) is most catalytic; (2) Active iron atom generated by the reduction of Fe₂O₃ is a catalyst for carbon monoxide disintegration; (3) The catalytic process consists of the adsorption of CO, the formation of intermediates FeC, Fe₂C , and Fe₃C , and the decomposition of these intermediates. / Ph. D.

Triaryl phosphates were synthesized from white phosphorus and phenols in aerobic conditions and in the presence of iron catalysts and iodine. Full conversion to phosphates was achieved without the use of chlorine or chlorinated solvents, and the reactions do not produce acid waste. Triphenyl phosphate, tritolyl phosphate and tris(2,4-di-tert-butyl)phenyl phosphate were synthesized by this method with 100% conversion from P₄. Various iron(III) diketonates were used to catalyse the conversion. Mechanistic studies showed the reaction to proceed via the formation of phosphorus triiodide (PI₃), then diphenyl phosphoroiodidate (O=PI(OPh)₂) before the final formation of triphenyl phosphate (O=P(OPh)₃). The nucleophilic substitution of O=PI(OPh)₂ with phenol to form O=P(OPh)₃ was found to be the rate determining step. It was found that by modifying the reaction conditions the same catalytic systems could be used to synthesize triphenyl phosphite directly from P₄. Triphenyl phosphite was synthesized in selectivities of up to 60 %. The mechanism of these transformations was also elucidated. Independent syntheses of the intermediate in the reaction mechanism, O=P(OPh)₂I and its hydrolysis products diphenyl phosphate (O=P(OPh)₂OH) and tetraphenyl pyrophosphate ((O)P(OPh)₂-O-P(O)(OPh)₂) were developed from PI₃. The 2,4-di-tert-butyl phenol analogues of these compounds were also prepared. Bis-(2,4-di-tert-butylphenyl) phosphoroiodidate was then reacted with various alcohols to produce a series of mixed triorgano phosphates.

M.Sc. / 2-(Pyrazol-1-ylmethyl)pyridine ligands were synthesised by phase transfer alkylation of 2-picolyl hydrochloride with the appropriate pyrazole. These ligands were subsequently reacted with NiCl2, NiBr2, FeCl2 or CoCl2 to form the respective complexes. The substituents on the pyrazole included phenyl and tert-butyl groups as well as electron withdrawing CF3 groups. The substituents played an important role in the steric and electrophilic nature of the metals. A second ligand design is 2,6-bis(pyrazol-1-ylmethyl)pyridine and were prepared by phase transfer alkylation of 2,6-bis(chloromethyl)pyridine with two mole equivalents of the appropriate pyrazole. These ligands were reacted with NiCl2, NiBr2, FeCl2 or CoCl2 to form the respective complexes. A third ligand design is 2-(chloromethyl)- or 2-(bromomethyl)-6-(pyrazol-1-ylmethyl)pyridine and were prepared by the selective alkylation of 2,6-bis(chloromethyl)pyridine with one mole equivalent of the appropriate pyrazole. These ligands were also reacted with NiCl2, NiBr2, FeCl2 or CoCl2 to form the respective complexes. Characterisation of all compounds was done by a range of spectroscopic techniques as well as X-ray crystallography and elemental analysis. The data showed good fit to the proposed structures and in a few cases were confirmed by X-Ray crystallography. All complexes were tested as catalysts for ethylene and higher olefin oligomerisation and showed good activity. The production of alkenes were confirmed in toluene and hexane, however, due to the use of EtAlCl2 and toluene the oligomers were alkylated to form the Friedel-Crafts alkylation products. Similar alkylation was observed for the higher olefin reactions. In comparison, the same reactions in hexane resulted in only C4, C6 and C8 oligomers. When higher olefin reactions were also conducted in hexane, polymeric solids were observed.

Thesis. 1977. Ph.D.--Massachusetts Institute of Technology. Dept. of Chemical Engineering. / M̲i̲c̲ṟo̲f̲i̲c̲ẖe̲ c̲o̲p̲y̲ a̲v̲a̲i̲ḻa̲ḇḻe̲ i̲ṉ A̲ṟc̲ẖi̲v̲e̲s̲ a̲ṉḏ S̲c̲i̲e̲ṉc̲e̲.̲ / Bibliography : leaves 286-295. / by Albert Sacco, Jr. / Ph.D.

Neste trabalho, foram investigados diferentes catalisadores à base de ferro, desde aspectos relacionados à sua preparação e caracterização até o seu desempenho na Síntese de Fischer-Tropsch. A abordagem incluiu a preparação de diferentes grupos de catalisadores e o estudo do efeito da temperatura de reação, da influência de parâmetros de síntese e do efeito da adição de cobalto e cobre às amostras sobre o seu desempenho catalítico. Os testes foram conduzidos por 6 h em reator tubular de leito fixo, sob pressão de 0,18 MPa, em temperaturas entre 280 e 320°C, carga de 500 mg e vazão de alimentação de 10 mL.min-1 da mistura H2/CO (razão molar 2:1) diluída em 40 mL.min-1 de N2. Além de aumentar a atividade do catalisador, o aumento da temperatura da reação resultou em maior seletividade para CO2, maior razão olefina/parafina, maior formação de coque e menor tendência à formação de produtos mais pesados. Nas condições empregadas, observou-se que a adição de cobre a catalisadores Fe-Si aumenta a área específica e a atividade da reação, mas a tendência à desativação por deposição de coque é elevada e a distribuição dos produtos é prejudicada. Quanto aos parâmetros de síntese, o tempo de cristalização e o agente precipitante pouco influenciaram a performance dos catalisadores, mas esta foi comprometida pelo tratamento térmico em atmosfera estagnada. O estudo dos catalisadores Fe-Al e Mg-Fe mostrou que há uma elevação significativa da área específica e de sua atividade quando há adição de um terceiro metal (cobre e cobalto). Também se verificou um sensível deslocamento para formação de produtos com cadeias carbônicas mais longas e uma diminuição da seletividade a CO2. A ativação com H2 das amostras contendo Co e Cu resultou na sinterização destes metais, sendo o último o mais afetado devido à redução do cobre ocorrer em menor faixa de temperatura, conforme mostrado pelos perfis de TPR. Maiores teores de cobre prejudicaram tanto a seletividade como a atividade dos dois grupos de catalisadores. As amostras do grupo Fe-Al apresentaram distribuição de produtos mais interessante do que as do grupo Mg-Fe e maiores conversões de CO para as amostras auto-ativadas contendo Cu. No entanto, os catalisadores do grupo Fe-Al, por possuírem maior acidez, apresentaram maior tendência à desativação por deposição de coque. O catalisador do tipo Cu-Fe-Al submetido a ciclos de reação-regeneração consecutivos apresentou contínua perda de atividade, associada à sinterização e à oxidação incompleta do coque. O acompanhamento do sinal de O2 durante os ensaios de regeneração sugeriu uma deposição de coque mais pesado para regenerações mais recentes. / Aspects related to preparation, characterization and performance for Fischer- Tropsch synthesis of iron-based catalysts were investigated in this work. The approach included the preparation of different groups of catalysts and the study of the effect of reaction temperature, the influence of synthesis parameters and the effect of adding cobalt and copper to samples over its catalytic performance. Tests were performed for 6 h in a tubular fixed bed reactor on 0.18 MPa, temperature between 280 and 320°C, 500 mg of catalyst and H2/CO (2:1 molar ratio) with a flow rate of 10 mL.min-1 diluted to 40 mL.min-1 N2 stream. In addition to improving catalyst activity, the increase in reaction temperatures resulted in higher selectivity to CO2, higher olefin-to-paraffin ratio, higher coke formation and lower tendency to form heavier products. Under these reaction conditions, the addition of copper to Fe-Si catalysts increased the specific surface area and reaction activity, but enhanced the deactivation tendency due to coke formation and affected the products distribution. Evaluating the synthesis parameters, the crystallization time and the precipitating agent had little influence over catalyst performance, but it was affected by the agent had little influence over catalyst performance, but it was affected by the thermal treatment on stagnant atmosphere. The study of Fe-Al and Mg-Fe catalysts showed a significant increase in specific surface area and in activity when a third metal (copper and cobalt) is added. A significant shift in selectivity towards higher chain length products and a lower selectivity to CO2 were also verified. H2 activation step of Co and Cu-containing samples resulted in sintering of these metals. The effect of sintering appeared to be more severe for Cu-containing catalyst once copper reduces in lower temperature range, as shown in TPR profiles. The increase of copper content had a detrimental effect over selectivity and activity of both catalyst groups. The Fe-Al catalysts showed more interesting product spectra distribution compared to Mg-Fe ones, and showed higher CO conversion for self-activated Cucontaining catalysts. Nevertheless, the Fe-Al group catalysts showed higher deactivation tendency due to coke deposition as they presented stronger acidity. The Cu-Fe-Al type catalyst submitted to consecutive reaction-regeneration cycles showed a continuous loss of activity associated to sintering and incomplete coke oxidation. The monitoring of O2 signal during regeneration tests suggested the formation of a heavier coke for earlier regeneration.

Thesis (M.S.)--Brigham Young University. Dept. of Chemical Engineering, 2006. / Includes bibliographical references (p. 89-95).

Neste trabalho, foram investigados diferentes catalisadores à base de ferro, desde aspectos relacionados à sua preparação e caracterização até o seu desempenho na Síntese de Fischer-Tropsch. A abordagem incluiu a preparação de diferentes grupos de catalisadores e o estudo do efeito da temperatura de reação, da influência de parâmetros de síntese e do efeito da adição de cobalto e cobre às amostras sobre o seu desempenho catalítico. Os testes foram conduzidos por 6 h em reator tubular de leito fixo, sob pressão de 0,18 MPa, em temperaturas entre 280 e 320°C, carga de 500 mg e vazão de alimentação de 10 mL.min-1 da mistura H2/CO (razão molar 2:1) diluída em 40 mL.min-1 de N2. Além de aumentar a atividade do catalisador, o aumento da temperatura da reação resultou em maior seletividade para CO2, maior razão olefina/parafina, maior formação de coque e menor tendência à formação de produtos mais pesados. Nas condições empregadas, observou-se que a adição de cobre a catalisadores Fe-Si aumenta a área específica e a atividade da reação, mas a tendência à desativação por deposição de coque é elevada e a distribuição dos produtos é prejudicada. Quanto aos parâmetros de síntese, o tempo de cristalização e o agente precipitante pouco influenciaram a performance dos catalisadores, mas esta foi comprometida pelo tratamento térmico em atmosfera estagnada. O estudo dos catalisadores Fe-Al e Mg-Fe mostrou que há uma elevação significativa da área específica e de sua atividade quando há adição de um terceiro metal (cobre e cobalto). Também se verificou um sensível deslocamento para formação de produtos com cadeias carbônicas mais longas e uma diminuição da seletividade a CO2. A ativação com H2 das amostras contendo Co e Cu resultou na sinterização destes metais, sendo o último o mais afetado devido à redução do cobre ocorrer em menor faixa de temperatura, conforme mostrado pelos perfis de TPR. Maiores teores de cobre prejudicaram tanto a seletividade como a atividade dos dois grupos de catalisadores. As amostras do grupo Fe-Al apresentaram distribuição de produtos mais interessante do que as do grupo Mg-Fe e maiores conversões de CO para as amostras auto-ativadas contendo Cu. No entanto, os catalisadores do grupo Fe-Al, por possuírem maior acidez, apresentaram maior tendência à desativação por deposição de coque. O catalisador do tipo Cu-Fe-Al submetido a ciclos de reação-regeneração consecutivos apresentou contínua perda de atividade, associada à sinterização e à oxidação incompleta do coque. O acompanhamento do sinal de O2 durante os ensaios de regeneração sugeriu uma deposição de coque mais pesado para regenerações mais recentes. / Aspects related to preparation, characterization and performance for Fischer- Tropsch synthesis of iron-based catalysts were investigated in this work. The approach included the preparation of different groups of catalysts and the study of the effect of reaction temperature, the influence of synthesis parameters and the effect of adding cobalt and copper to samples over its catalytic performance. Tests were performed for 6 h in a tubular fixed bed reactor on 0.18 MPa, temperature between 280 and 320°C, 500 mg of catalyst and H2/CO (2:1 molar ratio) with a flow rate of 10 mL.min-1 diluted to 40 mL.min-1 N2 stream. In addition to improving catalyst activity, the increase in reaction temperatures resulted in higher selectivity to CO2, higher olefin-to-paraffin ratio, higher coke formation and lower tendency to form heavier products. Under these reaction conditions, the addition of copper to Fe-Si catalysts increased the specific surface area and reaction activity, but enhanced the deactivation tendency due to coke formation and affected the products distribution. Evaluating the synthesis parameters, the crystallization time and the precipitating agent had little influence over catalyst performance, but it was affected by the agent had little influence over catalyst performance, but it was affected by the thermal treatment on stagnant atmosphere. The study of Fe-Al and Mg-Fe catalysts showed a significant increase in specific surface area and in activity when a third metal (copper and cobalt) is added. A significant shift in selectivity towards higher chain length products and a lower selectivity to CO2 were also verified. H2 activation step of Co and Cu-containing samples resulted in sintering of these metals. The effect of sintering appeared to be more severe for Cu-containing catalyst once copper reduces in lower temperature range, as shown in TPR profiles. The increase of copper content had a detrimental effect over selectivity and activity of both catalyst groups. The Fe-Al catalysts showed more interesting product spectra distribution compared to Mg-Fe ones, and showed higher CO conversion for self-activated Cucontaining catalysts. Nevertheless, the Fe-Al group catalysts showed higher deactivation tendency due to coke deposition as they presented stronger acidity. The Cu-Fe-Al type catalyst submitted to consecutive reaction-regeneration cycles showed a continuous loss of activity associated to sintering and incomplete coke oxidation. The monitoring of O2 signal during regeneration tests suggested the formation of a heavier coke for earlier regeneration.

Neste trabalho, foram investigados diferentes catalisadores à base de ferro, desde aspectos relacionados à sua preparação e caracterização até o seu desempenho na Síntese de Fischer-Tropsch. A abordagem incluiu a preparação de diferentes grupos de catalisadores e o estudo do efeito da temperatura de reação, da influência de parâmetros de síntese e do efeito da adição de cobalto e cobre às amostras sobre o seu desempenho catalítico. Os testes foram conduzidos por 6 h em reator tubular de leito fixo, sob pressão de 0,18 MPa, em temperaturas entre 280 e 320°C, carga de 500 mg e vazão de alimentação de 10 mL.min-1 da mistura H2/CO (razão molar 2:1) diluída em 40 mL.min-1 de N2. Além de aumentar a atividade do catalisador, o aumento da temperatura da reação resultou em maior seletividade para CO2, maior razão olefina/parafina, maior formação de coque e menor tendência à formação de produtos mais pesados. Nas condições empregadas, observou-se que a adição de cobre a catalisadores Fe-Si aumenta a área específica e a atividade da reação, mas a tendência à desativação por deposição de coque é elevada e a distribuição dos produtos é prejudicada. Quanto aos parâmetros de síntese, o tempo de cristalização e o agente precipitante pouco influenciaram a performance dos catalisadores, mas esta foi comprometida pelo tratamento térmico em atmosfera estagnada. O estudo dos catalisadores Fe-Al e Mg-Fe mostrou que há uma elevação significativa da área específica e de sua atividade quando há adição de um terceiro metal (cobre e cobalto). Também se verificou um sensível deslocamento para formação de produtos com cadeias carbônicas mais longas e uma diminuição da seletividade a CO2. A ativação com H2 das amostras contendo Co e Cu resultou na sinterização destes metais, sendo o último o mais afetado devido à redução do cobre ocorrer em menor faixa de temperatura, conforme mostrado pelos perfis de TPR. Maiores teores de cobre prejudicaram tanto a seletividade como a atividade dos dois grupos de catalisadores. As amostras do grupo Fe-Al apresentaram distribuição de produtos mais interessante do que as do grupo Mg-Fe e maiores conversões de CO para as amostras auto-ativadas contendo Cu. No entanto, os catalisadores do grupo Fe-Al, por possuírem maior acidez, apresentaram maior tendência à desativação por deposição de coque. O catalisador do tipo Cu-Fe-Al submetido a ciclos de reação-regeneração consecutivos apresentou contínua perda de atividade, associada à sinterização e à oxidação incompleta do coque. O acompanhamento do sinal de O2 durante os ensaios de regeneração sugeriu uma deposição de coque mais pesado para regenerações mais recentes. / Aspects related to preparation, characterization and performance for Fischer- Tropsch synthesis of iron-based catalysts were investigated in this work. The approach included the preparation of different groups of catalysts and the study of the effect of reaction temperature, the influence of synthesis parameters and the effect of adding cobalt and copper to samples over its catalytic performance. Tests were performed for 6 h in a tubular fixed bed reactor on 0.18 MPa, temperature between 280 and 320°C, 500 mg of catalyst and H2/CO (2:1 molar ratio) with a flow rate of 10 mL.min-1 diluted to 40 mL.min-1 N2 stream. In addition to improving catalyst activity, the increase in reaction temperatures resulted in higher selectivity to CO2, higher olefin-to-paraffin ratio, higher coke formation and lower tendency to form heavier products. Under these reaction conditions, the addition of copper to Fe-Si catalysts increased the specific surface area and reaction activity, but enhanced the deactivation tendency due to coke formation and affected the products distribution. Evaluating the synthesis parameters, the crystallization time and the precipitating agent had little influence over catalyst performance, but it was affected by the agent had little influence over catalyst performance, but it was affected by the thermal treatment on stagnant atmosphere. The study of Fe-Al and Mg-Fe catalysts showed a significant increase in specific surface area and in activity when a third metal (copper and cobalt) is added. A significant shift in selectivity towards higher chain length products and a lower selectivity to CO2 were also verified. H2 activation step of Co and Cu-containing samples resulted in sintering of these metals. The effect of sintering appeared to be more severe for Cu-containing catalyst once copper reduces in lower temperature range, as shown in TPR profiles. The increase of copper content had a detrimental effect over selectivity and activity of both catalyst groups. The Fe-Al catalysts showed more interesting product spectra distribution compared to Mg-Fe ones, and showed higher CO conversion for self-activated Cucontaining catalysts. Nevertheless, the Fe-Al group catalysts showed higher deactivation tendency due to coke deposition as they presented stronger acidity. The Cu-Fe-Al type catalyst submitted to consecutive reaction-regeneration cycles showed a continuous loss of activity associated to sintering and incomplete coke oxidation. The monitoring of O2 signal during regeneration tests suggested the formation of a heavier coke for earlier regeneration.

The structural and functional roles of lanthana in unsupported iron-based catalysts for the high-temperature water-gas shift reaction and Fischer-Tropsch synthesis were investigated. The performance of the catalysts with varying lanthana contents was based on their activity, selectivity, and stability. With regard to the former reaction, extent of reduction of the iron in Fe2O3/Cr2O3/CuO/La2O3 water-gas shift catalysts is a key parameter that was characterized using UV-visible spectroscopy. Minor addition of lanthana (<0.5 wt%) produces more active and stable catalysts apparently because it stabilizes the iron-chromium spinel, increases the surface area of the reduced catalysts, enhances the reduction of hematite to the magnetite active phase, and facilitates the adsorption of CO on the surface of the catalyst modeled by an adsorptive Langmuir-Hinshelwood mechanism. Statistical 95% confidence contour plots of the adsorption equilibrium constants show that water adsorbs more strongly than CO, which inhibits the reaction rate. A calibration curve that correlates the oxidation state of surface iron domains to normalized absorbance of visible light was successfully generated and applied to the water-gas shift catalysts. UV-visible studies indicated higher extent of reduction for surface Fe domains for the catalysts promoted with 1 wt% of lanthana and showed potential to be a more convenient technique for surface chemistry studies than X-ray absorption near edge spectroscopy (XANES). Lanthana addition to iron-based Fischer-Tropsch catalysts enhances the olefin-to-paraffin ratio, but decreases their activity, stability, and selectivity to liquid hydrocarbons. Adding lanthana at the expense of potassium reduces the water-gas shift selectivity and enhances the activity and stability of the catalysts. Finally, a model that simulates heat and mass transfer limitations on the particle scale for the Fischer-Tropsch reaction applicable at lab-scale suggests optimal operating and design conditions of 256°C, 30 bar, and 80 mirons are recommended for higher selectivity to liquid hydrocarbons. The model considers pressure drop, deactivation, pore diffusion, film heat transfer, and internal heat transfer when solving for the optimal conditions, and maps them as functions of design variables. This model can be up-scaled to provide guidance for optimal design of commercial-size reactors.