Dissertations / Theses: 'Alkane Oxidation'

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Kleinschmidt, Olaf. "Photokatalytische Oxidation von Alkenen und Alkanen mit Sauerstoff an belichtetem Titandioxid." [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=962781142.

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Grootboom, Natasha Denise. "Alkane oxidation using metallophthalocyanine as homogeneous catalysts." Thesis, Rhodes University, 2002. http://hdl.handle.net/10962/d1007794.

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Iron polychlorophthalocyanine (FePc(Cl)₁₆) and tetrasulfophthalocyanine ([M¹¹TSPc]⁴) complexes of iron, cobalt and manganese are employed as catalysts for the oxidation of cyclohexane using tert-butyl hydroperoxide (TBHP), chloroperoxybenzoic acid (CPBA) and hydrogen peroxide as oxidants. Catalysis using the FePc(Cl)₁₆ was performed in a dimethylformamide:dichloromethane (3 :7) solvent mixture. For the [Fe¹¹TSPc]⁴⁻, [Co¹¹TSPc]⁻ and [Mn¹¹TSPc]⁴⁻catalysts, a water:methanol (1:9) mixture was employed. The products of the catalysis are cyclohexanone, cyclohexanol and cyclohexanediol. The relative percentage yields, percentage selectivity and overall percentage conversion of the products depended on types of oxidant, or catalyst, concentrations of substrate or catalysts and temperature. TBHP was found to be the best oxidant since minimal destruction of the catalyst and higher selectivity in the products were observed when this oxidant was employed. Of the four catalysts investigated [Fe¹¹TSPc]⁴⁻ yielded the highest overall percentage conversion of 20%.The mechanism of the oxidation of cyclohexane in the presence of the FePc(Cl)₁₆ and [M¹¹TSPc]⁴⁻ involves the oxidation of these catalysts, forming an Fe(IlI) phthalocyanine species as an intermediate. Electrocatalysis using [Co¹¹TSPc]⁴⁻ as catalyst, employed an aqueous pH 7 buffer medium for electro-oxidation of 4-pentenoic acid. An enone is suggested as the only oxidation product of 4-pentenoic acid. No degradation of [Co¹¹TSPc]⁴⁻ was observed during the electrocatalytic process. In this process water was used as a source of oxygen therefore eliminating the production of by products from oxidant as in the case of TBHP and CPBA. This system was studied In an attempt to set up conditions for alkane electrocatalytic oxidation.

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Beilen, Jan Berthold van. "Alkane oxidation by Pseudomonas oleovorans: genes and proteins." [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 1994. http://irs.ub.rug.nl/ppn/292892500.

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4

Shang, Yuan. "Teabag technology in long chain alkane selective oxidation." Thesis, Cardiff University, 2014. http://orca.cf.ac.uk/66336/.

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This thesis describes the searching, preparation, characterization and catalytic evaluation of active catalysts for the terminal selectivity of long chain linear alkanes. The focus of the thesis is the study of shape selective materials, including the organic material cyclodextrins, and the inorganic material, zeolite and zeolitic membranes. Prepared catalysts were performed with n-decane or n-hexane as models to produce the terminal oxidation products 1-decanol, 1-hexanol, decanoic acid and hexanoic acid. Studies with the Andrews glass reactor showed a stable terminal selectivity of 5%-9% in the autoxidation of n-hexane in short time reactions. A comparison between the Andrews glass reactor and Parr stainless steel reactor showed that the autoxidation reactions can get higher conversion but lower terminal selectivity in the stainless steel reactor than the glass reactor. Most of the metal/support catalysts showed very low conversion and very poor terminal selectivity. Increasing the temperature leads to higher conversion but results in more cracked products and less selectivity for oxygenated C10 products. The most active catalyst was 5 w.t.% Au/TiO2. However, these catalysts did not show good terminal alcohol selectivity (<3%); whereas the cracked acid selectivity was high (32.0%). Cyclodextrin covered Au/SiO2 catalysts showed limited changes in terminal selectivities (1-2%). Zeolite 4A, silicalite-1, ZSM-5, zeolite X/Y coated catalysts were successfully synthesized with alumina and silica sphere supports. The most attractive oxidation results were performed by zeolite X/Y and zeolite 4A coated silica catalysts in n-hexane liquid phase oxidation, iv especially for with short reaction time. With zeolite X/Y membrane, in a 30 min reaction, the terminal selectivity was 16%, while the terminal selectivity for the blank reactions was 0-9%. With longer reaction time, the terminal selectivity decreased to 6-7%. Zeolite 4A membrane can produce a terminal selectivity of 13% in 4 h reactions.

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Guo, Chris. "Alkane Oxidation Catalysis by Homogeneous and Heterogeneous Catalyst." Thesis, The University of Sydney, 2005. http://hdl.handle.net/2123/622.

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Abstract Cobalt-based complexes are widely used in industry and organic synthesis as catalysts for the oxidation of hydrocarbons. The Co/Mn/Br (known as "CAB system") catalyst system is effective for the oxidation of toluene. The Co/Mn/Br/Zr catalyst system is powerful for the oxidation of p-xylene, but not for the oxidation of toluene. [Co3O(OAc)5(OH)(py)3][PF6] (Co 3+ trimer 5) is more effective than [Co3O(OAc)6(py)3][PF6] (Co 3+ trimer 6) as a catalyst in the CAB catalyst system. Higher temperatures favour the oxidation of toluene. Zr 4+ does not enhance the oxidation of toluene. Zr 4+ could inhibit the oxidation of toluene in the combination of Co/Br/Zr, Co/Mn/Zr or Co/Zr. NHPI enhances the formation of benzyl alcohol, but the formation of other by-products is a problem for industrial processes. Complex(es) between cobalt, manganese and zirconium might be formed during the catalytic reaction. However, attempts at the preparation of complexes consisting of Co/Zr or Mn/Zr or Co3ZrP or Co8Zr4 clusters failed. The oxidation of cyclohexane to cyclohexanone and cyclohexanol is of great industrial significance. For the homogeneous catalysis at 50 o C and 3 bar N2 pressure, the activity order is: Mn(OAc)3 �2H2O > Mn12O12 cluster > Co 3+ trimer 6 > [Co3O(OAc)3(OH)2(py)5][PF6]2 (Co 3+ trimer 3) > Co 3+ trimer 5 > Co(OAc)2 �4H2O > [Co2(OAc)3(OH)2(py)4][PF6]-asym (Co dimerasym) > [Co2(OAc)3(OH)2(py)4][PF6]-sym (Co dimersym); whereas [Mn2CoO(OAc)6(py)3]�HOAc (Mn2Co complex) and zirconium(IV) acetate hydroxide showed almost no activity under these conditions. But at 120 o C and 3 bar N2 pressure, the activity order is changed to: Co dimerasym > Co(OAc)2 �4H2O > Co trimer 3 and Mn(OAc)3 �2H2O > Co 3+ trimer 6 > Mn2Co complex > Co 3+ trimer 5 > Co dimersym > Mn12O12 cluster. The molar ratio of the products was close to cyclohexanol/cyclohexanone=2/1. Mn(II) acetate and zirconium(IV) acetate hydroxide showed almost no activity under these conditions. Among those cobalt dimers and trimers, only the cobalt dimerasym survived after the stability tests, this means that [Co2(OAc)3(OH)2(py)4][PF6]-asym might be the active form for cobalt(II) acetate in the CAB system. Metal-substituted (silico)aluminophosphate-5 molecular sieves (MeAPO-5 and MeSAPO-5) are important heterogeneous catalysts for the oxidation of cyclohexane. The preparation of MeAPO-5 and MeSAPO-5 and their catalytic activities were studied. Pure MeAPO-5 and MeSAPO-5 are obtained and characterised. Four new pairs of bimetal-substituted MeAPO-5 and MeSAPO-5(CoZr, MnZr, CrZr and MnCo) were prepared successfully. Two novel trimetal-subtituted MeAPO-5 and MeSAPO-5 (MnCoZr) are reported here. Improved methods for the preparation of four monometal-substituted MeAPO-5 (Cr, Co, Mn and Zr) and for CoCe(S)APO-5 and CrCe(S)APO-5 are reported. Novel combinational mixing conditions for the formation of gel mixtures for Me(S)APO-5 syntheses have been developed. For the oxidation of cyclohexane by TBHP catalysed by MeAPO-5 and MeSAPO-5 materials, CrZrSAPO-5 is the only active MeSAPO-5 catalyst among those materials tested under conditions of refluxing in cyclohexane. Of the MeAPO-5 materials tested, whereas CrCeSAPO-5 has very little activity, CrZrAPO-5 and CrCeAPO-5 are very active catalysts under conditions of refluxing in cyclohexane. MnCoAPO-5, MnZrAPO-5 and CrAPO-5 are also active. When Cr is in the catalyst system, the product distribution is always cyclohexanone/cyclohexanol equals 2-3)/1, compared with 1/2 for other catalysts. For MeAPO-5, the activity at 150 o C and 10 bar N2 pressure is: CrZrAPO-5 > CrCeAPO-5 > CoZrAPO-5. For MeAPO-5 and MeSAPO-5, at 150 o C and 13 bar N2 pressure, the selectivity towards cyclohexanone is: CrZrAPO-5 > CrZrSAPO-5 > CrCeAPO-5 > CrAPO-5 > MnCoAPO-5 > MnZrAPO-5; and the selectivity towards cyclohexanol is: MnZrAPO-5 > CrZrAPO-5 > MnCoAPO-5 > CrZrSAPO-5 > CrCeAPO-5 > CrAPO-5. Overall the selectivity towards the oxidation of cyclohexane is: CrZrAPO-5 > CrZrSAPO-5 > CrCeAPO-5 > CrAPO-5 > MnCoAPO-5 > MnZrAPO-5. The amount of water in the system can affect the performance of CrCeAPO-5, but has almost no effect on CrZrAPO-5. Metal leaching is another concern in potential industrial applications of MeAPO-5 and MeSAPO-5 catalysts. The heterogeneous catalysts prepared in the present work showed very little metal leaching. This feature, coupled with the good selectivities and effectivities, makes them potentially very useful.

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Guo, Chris. "Alkane Oxidation Catalysis by Homogeneous and Heterogeneous Catalyst." University of Sydney. Chemistry, 2005. http://hdl.handle.net/2123/622.

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Abstract Cobalt-based complexes are widely used in industry and organic synthesis as catalysts for the oxidation of hydrocarbons. The Co/Mn/Br (known as "CAB system") catalyst system is effective for the oxidation of toluene. The Co/Mn/Br/Zr catalyst system is powerful for the oxidation of p-xylene, but not for the oxidation of toluene. [Co3O(OAc)5(OH)(py)3][PF6] (Co 3+ trimer 5) is more effective than [Co3O(OAc)6(py)3][PF6] (Co 3+ trimer 6) as a catalyst in the CAB catalyst system. Higher temperatures favour the oxidation of toluene. Zr 4+ does not enhance the oxidation of toluene. Zr 4+ could inhibit the oxidation of toluene in the combination of Co/Br/Zr, Co/Mn/Zr or Co/Zr. NHPI enhances the formation of benzyl alcohol, but the formation of other by-products is a problem for industrial processes. Complex(es) between cobalt, manganese and zirconium might be formed during the catalytic reaction. However, attempts at the preparation of complexes consisting of Co/Zr or Mn/Zr or Co3ZrP or Co8Zr4 clusters failed. The oxidation of cyclohexane to cyclohexanone and cyclohexanol is of great industrial significance. For the homogeneous catalysis at 50 o C and 3 bar N2 pressure, the activity order is: Mn(OAc)3 �2H2O > Mn12O12 cluster > Co 3+ trimer 6 > [Co3O(OAc)3(OH)2(py)5][PF6]2 (Co 3+ trimer 3) > Co 3+ trimer 5 > Co(OAc)2 �4H2O > [Co2(OAc)3(OH)2(py)4][PF6]-asym (Co dimerasym) > [Co2(OAc)3(OH)2(py)4][PF6]-sym (Co dimersym); whereas [Mn2CoO(OAc)6(py)3]�HOAc (Mn2Co complex) and zirconium(IV) acetate hydroxide showed almost no activity under these conditions. But at 120 o C and 3 bar N2 pressure, the activity order is changed to: Co dimerasym > Co(OAc)2 �4H2O > Co trimer 3 and Mn(OAc)3 �2H2O > Co 3+ trimer 6 > Mn2Co complex > Co 3+ trimer 5 > Co dimersym > Mn12O12 cluster. The molar ratio of the products was close to cyclohexanol/cyclohexanone=2/1. Mn(II) acetate and zirconium(IV) acetate hydroxide showed almost no activity under these conditions. Among those cobalt dimers and trimers, only the cobalt dimerasym survived after the stability tests, this means that [Co2(OAc)3(OH)2(py)4][PF6]-asym might be the active form for cobalt(II) acetate in the CAB system. Metal-substituted (silico)aluminophosphate-5 molecular sieves (MeAPO-5 and MeSAPO-5) are important heterogeneous catalysts for the oxidation of cyclohexane. The preparation of MeAPO-5 and MeSAPO-5 and their catalytic activities were studied. Pure MeAPO-5 and MeSAPO-5 are obtained and characterised. Four new pairs of bimetal-substituted MeAPO-5 and MeSAPO-5(CoZr, MnZr, CrZr and MnCo) were prepared successfully. Two novel trimetal-subtituted MeAPO-5 and MeSAPO-5 (MnCoZr) are reported here. Improved methods for the preparation of four monometal-substituted MeAPO-5 (Cr, Co, Mn and Zr) and for CoCe(S)APO-5 and CrCe(S)APO-5 are reported. Novel combinational mixing conditions for the formation of gel mixtures for Me(S)APO-5 syntheses have been developed. For the oxidation of cyclohexane by TBHP catalysed by MeAPO-5 and MeSAPO-5 materials, CrZrSAPO-5 is the only active MeSAPO-5 catalyst among those materials tested under conditions of refluxing in cyclohexane. Of the MeAPO-5 materials tested, whereas CrCeSAPO-5 has very little activity, CrZrAPO-5 and CrCeAPO-5 are very active catalysts under conditions of refluxing in cyclohexane. MnCoAPO-5, MnZrAPO-5 and CrAPO-5 are also active. When Cr is in the catalyst system, the product distribution is always cyclohexanone/cyclohexanol equals 2-3)/1, compared with 1/2 for other catalysts. For MeAPO-5, the activity at 150 o C and 10 bar N2 pressure is: CrZrAPO-5 > CrCeAPO-5 > CoZrAPO-5. For MeAPO-5 and MeSAPO-5, at 150 o C and 13 bar N2 pressure, the selectivity towards cyclohexanone is: CrZrAPO-5 > CrZrSAPO-5 > CrCeAPO-5 > CrAPO-5 > MnCoAPO-5 > MnZrAPO-5; and the selectivity towards cyclohexanol is: MnZrAPO-5 > CrZrAPO-5 > MnCoAPO-5 > CrZrSAPO-5 > CrCeAPO-5 > CrAPO-5. Overall the selectivity towards the oxidation of cyclohexane is: CrZrAPO-5 > CrZrSAPO-5 > CrCeAPO-5 > CrAPO-5 > MnCoAPO-5 > MnZrAPO-5. The amount of water in the system can affect the performance of CrCeAPO-5, but has almost no effect on CrZrAPO-5. Metal leaching is another concern in potential industrial applications of MeAPO-5 and MeSAPO-5 catalysts. The heterogeneous catalysts prepared in the present work showed very little metal leaching. This feature, coupled with the good selectivities and effectivities, makes them potentially very useful.

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Sheppard, T. L. "Development of copper zeolite catalysts for selective alkane oxidation." Thesis, Queen's University Belfast, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.676734.

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Selective partial oxidation of methane to methanol was investigated over Cu-ZSM-5 with two main objectives: to improve catalytic activity through modification of the catalyst surface; and to work towards a low-temperature, gas phase catalytic process through building an understanding of the catalytic cycle. Na-ZSM-5 was modified by the commercial silylating agent BSTFA, synthesising a range of functionalised catalysts from 0.2-20% silylation by weight. Successful silylation was confirmed by DRIFTS. Following aqueous copper exchange td form functionalised Cu-ZSM-5, analysis by BET and transmission IR revealed selective exchange of catalytically active copper in the zeolite channels at 1-2% silylation, with reduced exchange of inactive copper on the external surface. The latter was also observed during TEM. A large increase in catalytic activity was determined by TPO-MS analysis. Silylation was therefore used to increase the proportion of catalytically active copper present, with potential application in the synthesis of more active catalysts.

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Yip, Wing-ping, and 葉永平. "Alkane C-H bond oxidations and alkene dihydroxylations by oxorutheniumcomplexes of chelating tertiary amine ligands." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B31246254.

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9

England, Jason. "Multidentate N-donor ligands in transition metal catalysed alkane oxidation." Thesis, Imperial College London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424716.

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10

Chung, Elena Yin-Yin. "Investigation of Chemical Looping Oxygen Carriers and Processes for Hydrocarbon Oxidation and Selective Alkane Oxidation to Chemicals." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469182957.

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11

Al-Sayari, Saleh Abdullah. "Synthesis of active supported gold catalysts for CO oxidation and light alkane activation." Thesis, Cardiff University, 2006. http://orca.cf.ac.uk/56051/.

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The preparation of gold catalysts supported on different metal oxides such as ZnO and Fe2O3, using two coprecipitation methods is investigated to determine important factors, such as selection of support material and preparation method, and preparation parameters, such as preparation temperature, pH, and ageing process. These factors control the synthesis of high activity catalysts for the oxidation of carbon monoxide at ambient temperature. The two preparation methods differ in the manner in which the pH is controlled during coprecipitation, either constant pH throughout or variable pH in which the pH is raised from an initial low value to a defined end point. Non- calcined Au/ZnO catalysts prepared using both methods are very sensitive to pH and ageing time. Catalysts prepared at higher pH give lower activity. However, all catalysts require a short indication period during which the oxidation activity increases. In contrast, the calcined catalysts are not sensitive to preparation conditions. Non-calcined Au/Fe203 catalysts exhibit high activity when prepared at pH > 5. Active calcined Au/Fe2O3 catalysts can be prepared when the pH is controlled at pH 6-7, 8, whereas calcined catalysts prepared using the variable pH method are inactive. The study demonstrates the immense sensitivity of catalyst preparation methods on the performance. Catalysts exhibited excellent catalytic activity and stability compared with the pure supports, ZnO and Fe2O3, and the best preparation temperature was 80 C. Use of temperatures > 80 C led to inactive catalysts. The deposition-precipitation (DP) method was also employed using four different supports in this study (ZnO, Fe2O3, MgO, and MnO2). A comparison between these catalysts was taken rather than an investigation of the effect of the preparation parameters on catalysts prepared by DP method because they have been well studied previously. Several characterization techniques including AAS, BET surface area, XRD, TPR, and XPS, were utilised to investigate the physical and chemical properties of the prepared supported gold catalysts. Characterization results were combined with catalytic results for the low temperature CO oxidation reaction of catalysts in order to study the aforementioned factors that can affect either the properties of catalysts or their activities. Subsequently, several experiments at high GHSV were conducted to study the catalytic activities of these catalysts in-depth and to correlate data with alkane activation reactions. CH4 activation reaction using supported gold catalysts at light temperatures and the effect of the preparation parameters, types of supports on catalysts activities were investigated. The Au/Fe2O3 catalyst prepared by coprecipitation method B at pH 8 showed the highest catalytic activity for CO oxidation and CH4 activation reactions. The most active catalysts were also evaluated for C2H6 and C3H8 activation at low temperature. After this, a comparison between CO oxidation and alkane activation over supported gold catalysts was undertaken to investigate the relationship between the behaviour of supported gold catalysts for these two types of reactions. Activation energies and pre-exponential factors of many catalysts were calculated based on the Arrhenius equation either for CO oxidation or for alkane activation. The preparation of gold catalysts supported on different metal oxides such as ZnO and Fe2O3, using two coprecipitation methods is investigated to determine the important factors that control the synthesis of high activity catalysts for the oxidation of carbon monoxide at ambient temperature. (Abstract shortened by UMI.)

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Pollard, Ashleigh J. J. "Silica and boron nitride supported molybdenum and vanadium oxide catalysts for alkane oxidation." Thesis, Cardiff University, 2004. http://orca.cf.ac.uk/55535/.

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A range of silica supported molybdenum catalysts and vanadium catalysts have been prepared and tested for alkane oxidation. Further vanadium catalysts supported on boron nitride have also been prepared and tested for alkane oxidation. The silica supported molybdenum oxide catalysts demonstrated appreciable activity for propane total oxidation to carbon oxides with some trace acrolein. The silica supported vanadium catalysts were also active for propane oxidation, and although the major product was carbon dioxide, higher selectivity to acrolein was observed when compared to the silica supported molybdenum catalysts. The use of boron nitride as a support significantly increased the selectivity towards acrolein and other selective oxidation products like acrylic acid. These results lead to the catalysts being tested for propene oxidation, which produced similar results that showed the boron nitride supported vanadium catalysts were more selective than the silica supported catalysts for acrolein. Further tests were carried out on methane and ethane, which produced mostly carbon oxides as a result. The effect of co-feeding water was also tested when performing propane oxidation with the presence of water effecting the selectivity and activity of the catalysts. Some catalyst's activity was suppressed with increased selectivity to acrolein and other catalysts activity was promoted which led to total oxidation to carbon oxides. This study aim is to compare and contrast the different catalysts produced and give evidence about how the use and development of a hydrophobic support may lead to better catalyst design in the future.

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García, Ojeda José Luis [Verfasser], and Rudolf [Akademischer Betreuer] Müller. "Oxidation of long-chain n-alkanes by mutants of a thermophilic alkane-degrading bacterium: Thermus sp. ATN1 / José Luis García Ojeda. Betreuer: Rudolf Müller." Hamburg-Harburg : Universitätsbibliothek der Technischen Universität Hamburg-Harburg, 2014. http://d-nb.info/1048647358/34.

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Williams, Dara Bridget. "Tridentate, dianionic ligands for alkane functionalization with platinum(II) and oxidation of iridium(III) hydrides with dioxygen /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/8545.

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Prat, Casellas Irene. "Bioinspired non-heme iron catalysts for challenging oxidative transformations: mechanistic studies and catalytic applications on selective alkane hydroxylation and alkene cis-dihydroxilation." Doctoral thesis, Universitat de Girona, 2013. http://hdl.handle.net/10803/117778.

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The functionalization of hydrocarbons in a sustainable manner is one of the main challenges for chemists. Their abundance in nature as natural gas or crude oil makes them the most convenient chemical feedstock. The oxidation of hydrocarbons is one of the most interesting reactions, because the introduction of an oxygen atom introduces functionality in these molecules, increasing their value as reagents for further chemical transformation. However, these reactions are fundamentally difficult due to the low reactivity of alkyl C-H bonds. Current available methodologies involve highly reactive-oxidizing reagents, high temperatures and long-time reactions in order to overcome this lack of reactivity. These harsh conditions introduce drawbacks in terms of chemo- and regioselectivity, essential to produce synthetic valuable products. An important step forward is the development of one-step oxidation methodologies, allowing the oxidation of C-H and C=C with high regio- and stereoselectivity. Natural systems, such as iron enzymes, are capable of perform this chemistry with high selectivity and efficiency. Iron is the most abundant metallic element in the earth and is essential for live. In addition, this lack of toxicity makes it and attractive material to substitute more toxic and expensive metals currently used. One of the main objective of this thesis is design of iron complexes that mimics the structure and function of these natural enzymes with the aim of find new methodologies for the selective C-H and C=C bond oxidation using green conditions. Furthermore, the study of these compounds could give useful information about the oxidation mechanisms operating in oxygenase enzymes. The results obtained in this thesis clarify the mechanism by which the oxidation of the C-H bond with retention of stereochemistry takes place at a mononuclear non-heme iron site, and evidence the formation of a high valent iron (V) capable of perform the cis-dihydroxylation of alkenes. Furthermore, a new complex is described as an efficient and selective catalyst capable of performing this chemistry in a scale amenable for synthetic applications
La funcionalització d'hidrocarburs de manera sostenible i eficaç és un dels principals reptes per la química moderna, degut a que la seva abundància natural els fa una important matèria primera. L'oxidació d'hidrocarburs és una de les reaccions més interessants, ja que la introducció d’un àtom d’oxigen en l’estructura d’un hidrocarburs li confereix funcionalitat química, fa augmentar el seu valor i els converteix en reactius adients per subseqüents transformacions químiques. No obstant això, aquestes reaccions són difícils a causa de la inherent baixa reactivitat dels hidrocarburs. Les metodologies actualment disponibles impliquen la utilització d’espècies altament oxidants i tòxiques, altes temperatures i llargs temps de reacció per tal de superar aquesta manca de reactivitat. Aquestes condicions extremes eviten que la química es pugui dur a terme de manera selectiva, fet essencial per produir productes d’alt valor sintètic. Un avanç important és el desenvolupament de metodologies de reacció suaus que permetin l'oxidació d'enllaços C-H i C=C amb alta regio- i estereoselectivitat. Els sistemes naturals, com ara enzims de ferro, són capaços de realitzar aquesta química. El ferro és l’element metàl•lic més abundant a la terra i és clau per nombrosos processos vitals, a més la seva baixa toxicitat el fa un atractiu material per substituir els elements de segona i tercera seria de transició més cars i tòxics emprats actualment. Un dels principals objectius d’aquesta tesi és dissenyar catalitzadors de ferro que imiten l’estructura i la funció dels enzims naturals per tal de trobar una nova metodologia que permeti l'oxidació selectiva d'enllaços C-H i C=C utilitzant condicions suaus i mediambientalment més benignes que les metodologies tradicionals. A més, l’estudi d’aquests sistemes pot donar informació útil sobre el mecanisme d’oxidació del propi enzim. Els resultats obtinguts en aquesta tesi aclareixen el mecanisme pel qual es duu a terme la hidroxilació de l’enllaç C-H amb retenció de la estereoselectivitat en centres mononuclears de ferro, i evidencien la formació d’una espècie de ferro (V) d’alt estat d’oxidació capaç de catalitzar la cis-dihidroxilació d’alquens. A més a més, es descobreix un catalitzador eficient i selectiu capaç de dur a terme aquesta química en condicions d’escala preparativa

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Wolfram, Till [Verfasser], Robert [Akademischer Betreuer] Schlögl, Reinhard [Akademischer Betreuer] Schomäcker, and Nicola [Akademischer Betreuer] Pinna. "Trägereinfluss bei Vanadiumoxid-Katalysatoren zur selektiven Oxidation kurzkettiger Alkane / Till Wolfram. Gutachter: Robert Schlögl ; Reinhard Schomäcker ; Nicola Pinna. Betreuer: Robert Schlögl." Berlin : Technische Universität Berlin, 2015. http://d-nb.info/1067388680/34.

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17

Chan, Wing-kei, and 陳永基. "Oxidation of alkenes and alkynes catalyzed by a cyclodextrin-modified ketoester and metalloporphyrins." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B36709591.

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Chan, Wing-kei. "Oxidation of alkenes and alkynes catalyzed by a cyclodextrin-modified ketoester and metalloporphyrins." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B36709591.

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19

Malumbazo, Nandi. "Immobilized catalysts for alkene oxidation." Thesis, University of the Western Cape, 2007. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_1206_1257925149.

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Tertiary butyl substituted and unsubstituted Schiff base systems containing N,O donor ligands (Salicylaldimines) with aminotriethoxysilane tail were synthesized and complexed to Copper and Cobalt acetate. In this study, the effect of metal, reaction time, nature of oxidant (hydrogen peroxide tertiary butyl hydroperoxide), substituents on thel igand and substrate concentration, were investigated.

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20

Gómez, Martín Laura. "Bioinspired iron and manganese catalysts for the effective and selective oxidation of alkanes and alkenes." Doctoral thesis, Universitat de Girona, 2010. http://hdl.handle.net/10803/8056.

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La gran eficiència, selectivitat i les condicions suaus exhibides per les reaccions que tenen lloc al centre actiu de les metal·looxigenases són la font d'inspiració per la present dissertació. Amb l'objectiu de dissenyar catalitzadors d'oxidació eficients hem fet ús de dues estratègies: la primera consisteix en el disseny de complexos amb baix pes molecular inspirats en aspectes estructurals de la primera esfera de coordinació del centre metàl·lic d'enzims de ferro i de manganès. Aquests complexos s'han estudiat com a catalitzadors en l'oxidació selectiva d'alcans i d'alquens fent servir oxidants "verds" com ara l'H2O2. La segona estratègia està basada en l'ús de la química supramolecular per tal de desenvolupar estructures moleculars auto-acoblades amb la forma i les propietats químiques desitjades. Concretament, la construcció de nanocontenidors amb un catalitzador d'oxidació incrustat a la seva estructura ens permetria dur a terme reaccions més selectives, tal com passa en les reaccions catalitzades per enzims.
The high efficiency, selectivity and mild conditions exhibited by the reactions that take place in the active site of metallooxygenases are the source of inspiration of the present dissertation. With the aim of designing efficient oxidation catalysts, we make use of two different strategies: the first one is the design of low molecular weight complexes inspired by structural aspects of the first coordination sphere of the metal active site of non-heme iron and manganese enzymes. These complexes are studied as catalysts for the selective oxidation of alkanes and alkenes using green oxidants such as H2O2. The second strategy is based on the use of supramolecular chemistry to develop self-assembled molecular structures with desired shape and chemical properties. Particularly, the construction of cavity-containing 3D nanovessels with an oxidation catalyst embedded in their structures would allow us to perform more selective reactions, analogously to the reactions catalyzed by enzymes.

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Janson, Pär. "Oxidative Trifluoromethylation and other Functionalization Reactions of Alkenes and Alkynes." Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-103064.

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This thesis concerns the use of various potent oxidants in organic synthesis. The main focus is directed at selectively introducing trifluoromethyl groups into compounds containing double or triple bonds. All reactions proceed under mild conditions and can in most cases be performed on the bench-top. We have developed three different procedures for transformations of activated alkenes and alkynes as well as quinones. In paper I the selective introduction of a trifluoromethyl group together with an oxygen functionality to double and triple bonds is demonstrated. Paper II is focused on the related chemoselective cyanotrifluoromethylation in which a cyano group is added instead of the oxygen functionality. Paper III describes a new procedure for C–H trifluoromethylation of quinones. Our studies on the mechanistic aspects of the above reactions are described in Paper IV. In these studies we investigated the ligand and substituent effects in Cu-catalyzed reactions. Paper V is focused on a conceptually new palladium-catalyzed allylic C–H acyloxylation of olefins under oxidative conditions. The procedure uses an inexpensive, safe and environmentally benign oxidant, sodium perborate, which is activated with acetic anhydride.

At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Submitted.

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Dobson, P. "The electrophilic halogenation, prevost oxidation and peroxydisulphate oxidation of alkenes." Thesis, University of York, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377280.

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Rode, Katharina. "Studies Toward Selenium-pi-Acid Catalyzed Oxidative Functionalizations of Olefinic and Acetylenic Multiple Bonds." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2020. http://hdl.handle.net/21.11130/00-1735-0000-0005-1491-0.

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24

Yeo, Benjamin Roy. "Alkanes, alkenes and aromatics : the oxidative dehydrogenation of n-octane using iron molybdate catalysts." Thesis, Cardiff University, 2014. http://orca.cf.ac.uk/76035/.

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The oxidative dehydrogenation (ODH) of n-octane to produce octene at atmospheric pressure has been studied using an industrially supplied iron molybdate catalyst from Johnson Matthey (JM). In situ X-ray diffraction studies revealed at temperatures ≥450 °C the catalyst undergoes a reductive phase transition when reacted with noctane at 450 °C where the phase changes from Fe2(MoO4)3-MoO3 to FeMoO4-MoO2-Mo4O11. As a result, if the temperature is taken back below this point the catalyst does not revert to the original phase and therefore the same activity and selectivity cannot be achieved.

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Su, Yee San 1977. "The heterogeneous partial oxidation of light alkanes." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28306.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2004.
Includes bibliographical references.
(cont.) With this approach, an upper bound on the yield for OCM was computed. Results showed that even with optimal surface chemistry, strict limits existed on the attainable yield. Surface energetics necessary for superior OCM performance were identified and the origins of these requirements elucidated. The resulting upper bound on OCM yield under conventional, packed-bed, continuous-feed operation was found to be 28%. The catalytic properties of LiCl/sulfated ZrO₂-based catalysts were explored for ODHE. LiCl was shown to strongly interact with the acid sites on sulfated ZrO₂ (SZ), influencing its catalytic behavior. Two approaches were taken to modify the nature/strength of the LiCl-support interaction. Firstly, LiCl/Nd₂O₃-impregnated MoO/ZrO₂ and WOx/ZrO₂ were examined. Unlike SZ, these supports allowed for the tailoring of MoO[sub]x and WO[sub]x surface densities, which in turn drastically altered their ODHE performance. The poor stability of these supports, however, rendered them inferior to SZ. Secondly, the effects of dopant incorporation on the catalytic behavior of LiCI/MO,/SZ were studied. Si-doped ZrO₂-based catalysts synthesized via the sol-gel method were found to exhibit superior activity, selectivity and stability for ODHE. Sulfate decomposition experiments related the ODHE activity of these materials to the influence of the Si dopant on the sulfate binding strength. The sol-gel synthesis conditions were optimized with respect to sol pH, water:alkoxide ratio and silicon precursor, achieving improved catalyst homogeneity and enhanced ODHE performance ...
Within the petrochemical industry, a sizeable economic incentive exists for the upgrading of low-value, light alkanes. For instance, the dehydrogenation of ethane to ethene is of considerable interest due to ethene's use as a polymeric and chemical precursor. Partial oxidation provides an attractive alternative to standard pyrolysis methods for alkane-to-alkene conversion. Unlike pyrolysis, partial oxidative routes are largely unaffected by coke formation and have the added benefit of exothermicity. With the inclusion of oxygen as a reactant, however, numerous additional reaction pathways result. Among these, the presence of parallel and consecutive reaction channels to CO[sub]x products is of major concern. For this reason, previous efforts to create selective partial oxidation catalysts with high activity have typically fallen below economic feasibility requirements. This thesis focuses on the following alkane-to-alkene transformation reactions: Oxidative Coupling of Methane (OCM): 2CH₄ + O₂ <--> C₂H₄ + 2 H₂O Oxidative Dehydrogenation of Ethane (ODHE): C₂H₆ + 1/2 O₂ <--> C₂H₄ + H₂O Oxidative Dehydrogenation of Propane (ODHP): C₃H₈ + 1/2 O₂ <--> C₃H₆ + H₂O. Regarding OCM, an approach was presented for determining an upper bound on the yield of a catalytic process, which allowed for variations in the catalytic chemistry. Scaling and thermodynamic arguments were used to set parameters of an elementary step surface mechanism at values resulting in optimal yields, subjected only to physical constraints. Remaining unknowns were treated as independent variables and varied over a broad range. The result was a set of thermodynamically consistent mechanisms with optimal kinetics that could be incorporated into reactor-transport models.
by Yee San Su.
Ph.D.

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26

Grant, C. R. "Evaluation of the bio-oxidation of alkanes." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1367613/.

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This thesis documents the progress made in utilising the alkane hydroxylase complex of P.putida GPo1 expressed in E.coli as a whole-cell biocatalyst for the oxidation of n-dodecane to 1-dodecanol. The process is of considerable interest due to the difficulty in performing the reaction using conventional chemistry and the large global market for fatty alcohols. The first results chapter compares the fermentative bio-oxidations using E.coli pGEc47ΔJ on n-octane and n-dodecane in a stirred tank reactor. The first reported conversion of n-dodecane in-vivo using this enzyme system in a recombinant host is reported. A number of bottlenecks were identified in this chapter; in particular, (i) poor induction of the alkS expression system with ndodecane, which controls the expression of the alk enzymes (ii) a suspected mass transport limitation (iii) substantial over-oxidation of the desired 1- dodecanol product to dodecanoic acid. The second results chapter firstly describes the development of a microwell platform in order to characterise the system more efficiently. Phase mixing limitations and organic phase spillage/evaporation were overcome in order to develop the microwell platform for the fermentative bio-oxidation which is the first reported microwell scale-down which matches the volumetric and specific rates achieved in a bioreactor for a substrate of such low solubility. Secondly, the microwell platform was used with design of experiments (DoE) methodology to rapidly and systematically characterise the overoxidation issue and identify appropriate solutions. Using this approach, substrate solubility was identified as the most critical factor affecting the tendency for overoxidation; the use of cosolvents to improve n-dodecane solubility in the aqueous phase was found to improve the 1-dodecanol yields and reduce dodecanoic acid yields. Oxygen availability and carbon source availability also proved important factors in the extent of overoxidation. Despite the improvements made the problem was only partially overcome and it was decided, based on the results, that biological engineering of the strain was necessary to remove the downstream aldehyde dehydrogenase alkH which was likely to be exacerbating overoxidation. The process of designing and constructing 3 new plasmids is described in results chapters four and five. These plasmids were designed with the aim of identifying the role of various alk proteins and ultimately identifying ways of improving substrate access to the enzyme and reducing overoxidation. It was found as a result of this work that overoxidation was reduced by removal of alkH but that the alkane-1-monooxygenase alkB was still capable of direct overoxidation to the dodecanoic acid even in the absence of alkH. More significantly, the function of an outer membrane protein of unknown function was also confirmed by this work. It was found to be essential for conversion of n-dodecane in-vivo but was also found to be toxic to the host organism when overexpressed. Finally, it was found that the alkane-1-monooxygenase enzyme system was also capable of C14 and C16 alkane oxidation; this has not previously been reported in literature in-vivo.

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Frunzke, Jan. "Quantenchemische Untersuchungen an übergangsmetallkatalysierten Oxidationsreaktionen die Oxidation von Alkenen mit Rutheniumtetraoxid /." [S.l. : s.n.], 2003. http://archiv.ub.uni-marburg.de/diss/z2003/0190/.

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RaviJayaKumar, K., University of Western Sydney, and Faculty of Science and Technology. "Selective oxidation of adamantane by metal complexes." THESIS_FST_XXX_RaviJayaKumar_ K.xml, 1997. http://handle.uws.edu.au:8081/1959.7/369.

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A series of tri-substituted iron and cobalt complexes of the form [M(A)3]n+ were synthesized, and were characterised by UV/Visible absorption and 1H-NMR spectroscopy. The complexes [Co(phen)2(en)]3+ and [Co(bipy)2(en)]3+ have been reported in the literature but 1H-NMR spectroscopy showed that the material produced in both syntheses is [Co(en)3]3+. Spectroscopy further showed that these species cannot be prepared by the literature methods. The complexes were tested in the oxidation of adamantane in the solvents, acetic acid and trifluoroacetic acid and they all oxidised adamantane to a mixture of 1-adamantanol, 1-adamantanol and 2-adamantanone both in the presence and the absence of the oxidant, O2. In all the reactions, however, the yield of conversion was very low. The mechanism for this oxidation was different depending on the presence or absence of O2. In the presence of O2 a catalytic cycle was produced for the oxidation of adamantine. In the oxidation in the presence and absence of O2 there was little variation in activity between the tri-substituted iron and cobalt complexes of 1,10-phenanthroline when compared with the analgous 2,2’-bipyridine complexes. However, the substitution of an ethylenediamine ligand into the co-ordination sphere of cobalt produced significant increase in the activity, although the change was not constant.
Master of Science (Hons)

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29

Stothard, Nigel David. "The oxidation of trans-2-butene and propene between 400 and 520 degree C." Thesis, University of Hull, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333710.

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Stevenson, Julie-Anne. "Selective oxidation of simple alkanes by cytochrome P450cam." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302491.

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31

Clarasó, Petit Carlota. "Rational design of bioinspired iron and manganese catalysts for the effective and selective epoxidation of alkenes and oxidation of alkanes." Doctoral thesis, Universitat de Girona, 2019. http://hdl.handle.net/10803/666958.

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Metalloenzymes are a fundamental source of inspiration for synthetic chemists. Oxidation metalloenzymes catalyze oxidation reactions with high efficiency under very mild experimental conditions exhibiting exquisite regio- and stereoselectivity. The present dissertation aims at designing efficient and selective bioinspired oxidation catalysts. Looking at the literature there’s a very limited number of aliphatic diamines incorporated as ligand backbones in tetradentate aminopyridine based complexes, which have been revealed as one of the most successful catalysts for these transformations with peroxide type of oxidants. Thus, this thesis is focused on the synthesis of chiral iron and manganese complexes based on novel diamine backbones and employ them as catalysts in the stereoselective epoxidation of olefins and oxidation of C-H bonds by using hydrogen peroxide as oxidant
Els metal·loenzims són una font fonamental d'inspiració per als químics sintètics. Els metal·loenzims oxidants catalitzen reaccions d'oxidació amb gran eficiència sota condicions experimentals molt suaus que presenten regio- i estereoselectivitats exquisides. L'objectiu d’aquesta tesi es basa en el disseny de catalitzadors d'oxidació bioinspirats eficients i selectius. Analitzant la literatura, es denota que hi ha una limitació important en el nombre i la naturalesa de la diamina incorporada als lligands en complexos basats en lligands tetradentats amb aminopiridines, que s'han demostrat com uns dels catalitzadors més exitosos per a aquestes transformacions amb oxidants de tipus peròxid. Així doncs, aquesta tesi se centra en la síntesi de complexos quirals de ferro i manganès basats en lligands tetradentats que incorporen noves diamines i el seu ús com a catalitzadors en l'epoxidació estereoselectiva d’olefines i l'oxidació dels enllaços C-H utilitzant el peròxid d'hidrogen com a oxidant

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32

Bawaked, Salem Mohammed. "Solvent free alkene oxidation using supported nano-gold catalysts." Thesis, Cardiff University, 2011. http://orca.cf.ac.uk/55088/.

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Oxidation is an important route for the activation of chemical feedstock for the synthesis of chemical intermediates. Alkene epoxidation by the electrophilic addition of oxygen to a carbon-carbon double bond is a major challenge in oxidation catalysis. In particular it is important to use molecular oxygen as the oxidant to avoid the formation of reagent by products. Although molecular oxygen is the most environmentally benign oxidant in many cases, far more reactive forms of oxygen are required to achieve reaction, and this can lead to by-products with a heavy environmental burden with respect to their disposal. Free solvent selective epoxidation of cw-cyclooctene with air and small catalytic amount of radical initiator using supported nano-gold catalysts has been conducted in the liquid phase. Optimization of reaction conditions has been attempted to improve the selectivity by minimizing the background reactions of the support and radical initiator in the absence of the catalyst. Five different radical initiators were tested namely: di-/-butyl peroxide (DTBP), /-butyl hydroperoxide (TBHP), cumene hydroperoxide (CHP), azobisisobutyronitrile (AIBN) and dibenzoyl peroxide (DBP). TBHP was selected for more detailed study as it combine the best activity and selectivity in the presence of the catalyst and minimum background reactions in the absence of the catalyst. The influence of the metal nano-particle support was also studied using six different supports. Use of graphite as a support was found to give the best combination of selectivity and conversion. In general the selectivity to the epoxide increased with reaction temperature from 60-80 C and was highest at 80 C. Other carbon supports, e.g. activated carbon and silicon carbide were found to be less effective. Au supported on TiO2, SiO2 and AI2O3 catalysts were also selective for the epoxidation reaction and the general order of activity was: graphite > SiC > TiO2 > SiO2 AI2O3 Ac. Extensive studies concerning the reusability of the gold/graphite catalyst was conducted as catalyst reusability is a key feature of green chemistry. The catalyst is found to be inhibited by the epoxide product but we demonstrate the effect of this is negligible for reused catalysts over a long reaction time. The observation of an induction period may in part be due to the adsorption of the radical initiator blocking surface sites as well as the establishment of the reactive species. The use of bimetallic catalyst, to be exact Au-Pd supported on graphite, shows significant effect on c/s-cyclooctene reactivity. The Au-Pd ratio has a major effect on the conversion with very low activities being associated with Au:Pd weight ratios of ca. 4:1 and 1:4 which may be associated with structured alloys that can be formed at these compositions. The molar Pd surface percentage were found to have dramatic effect on the conversion as low Pd surface would produce low activity and contrariwise. The selectivity to the epoxide is not affected by the Au:Pd ratio. Catalyst preparation method was also studied and sol immobilization method was found to be the most effective for gold catalyst, however, DP method was the preferred one in the bimetallic catalysts. The Au-Pd/graphite catalyst series has been further evaluated using crotyl alcohol (trans- but-2-en-l-ol) as starting material and using the same reaction conditions that had adopted for the epoxidation of c/s-cyclooctene. With crotyl alcohol, /-butyl hydroperoxide was not required for activity. In the absence of Pd, crotonaldehyde was formed, but the introduction of Pd leads to an isomerisation pathway to 3-buten-l-ol being favored over epoxidation and crotonaldehyde was a minor product. Dimerisation of crotonaldehyde and carbon carbon bond cleavage was observed with Au catalyst. However, with Pd catalysts Wacker-like oxidation of the isomerisation pathway was the major by-product.

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33

Huguet, Edouard. "Terminal oxidation of long linear alkanes in liquid phase." Thesis, Cardiff University, 2009. http://orca.cf.ac.uk/54952/.

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The aim of this project is to investigate the terminal activation of long chain linear alkanes in the liquid phase using the selective oxidation of w-decane to 1-decanol as a model reaction. Firstly the autoxidation of -decane with oxygen was studied. The product distribution is a mixture of Cio ketones and alcohols with shorter chain carboxylic acids. The radical autoxidation mechanism promotes oxidation in the internal position and a very low terminal selectivity is found in the product profile. A range of VMgO catalysts were tested for the oxidation of w-decane with oxygen. Leached vanadium from VMgO leads to an improvement to the conversion over the autoxidation while the same terminal selectivity was observed. Cobalt substituted zeolites catalysts were also investigated. The porous structure of the different zeolites did not improve the terminal selectivity. No cobalt leaching was observed. The silanation of the external surface of the zeolites before ion exchange with cobalt reduces the conversion compared to the same cobalt zeolites without silanation, but does not improve the terminal selectivity. Finally, a comparison of the best results published in the literature for the oxidation of n-hexane in the liquid phase has been carried out. Higher terminal selectivities for the autoxidation were observed than those reported. Autoxidation terminal selectivities match with the best catalysts reported in the literature.

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34

OÌlason, Gunnar B. "IT : oxidations of alkanes and alkenes by T butyl hydroperoxide or molecular oxygen catalysed by polybenzimidazole supported metal complexes." Thesis, University of Strathclyde, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249843.

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35

Bode, Kirstin S. "OPTIMIZATION OF IRIDIUM AND RUTHENIUM CATALYSTS IN THE C-H OXIDATION OF ALKANES." Kent State University Honors College / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ksuhonors1620909877637546.

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36

Apple, Ian Allan. "The alkaline peroxide oxidation of quinolinium salts." Thesis, University of Sunderland, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288879.

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37

Smith, David Andrew. "Oxidation of alkenes in the gas phase." Thesis, University of York, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341095.

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38

Adams, Melissa Marie. "The anaerobic oxidation of short-chain alkanes in hydrothermal vents." Thesis, Harvard University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3626342.

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Microorganisms are central to the cycling of methane on Earth. The anaerobic oxidation of methane (AOM) is a globally important process in anoxic marine sediments, which is often coupled to the reduction of sulfate by anaerobic methanotroph (ANME) archaea and sulfate reducing bacteria (SRB). However, the environmental and geochemical conditions that constrain these microbial communities remain largely uncharacterized. In this dissertation, I present evidence that methane and C₂-C₄ alkanes are substantial sources of metabolic energy in sedimented hydrothermal vent systems. Furthermore, these studies demonstrate that AOM and C₂-C₄ alkane oxidation linked to sulfate reduction (SR) are governed by temperature and substrate availability.

Using continuous-flow sediment bioreactors and batch incubations, rate measurements revealed a striking uncoupling of AOM from SR across the thermal gradient characteristic of hydrothermal vent sediments, with AOM occurring at the highest temperature (90°C) in the absence of SR. I discovered that ANMEs were present in sediments at all temperatures investigated, including a unique thermophilic ANME clade, while SRB were only detected in cooler regimes. Next, I present data from batch incubations demonstrating for the first time that substantial C₂-C₄ alkane oxidation occurs over a broad temperature range (25 - 75°C) in hydrothermal vent sediments and is coupled to SR up to 75°C with maximum rates at 55°C. Furthermore, there was preferential degradation of C₂-C₄ alkanes at 55°C, indicating that the active alkane oxidizers are thermophilic. At the rate maxima, 16S rRNA pyrotag sequence data revealed that a novel SRB lineage was the likely phylotype mediating the anaerobic oxidation of C₂-C₄ alkanes.

Finally, I present a comparative study of methane- and sulfur-cycling ecotypes in geographically separated hydrothermal vent and hydrocarbon seep sediments. By employing high throughput sequencing of 16S rRNA genes coupled to geochemical data, I was able to establish the environmental constraints that determine ANME and SRB ecotype diversity and distribution in these biogeochemically distinct deep sea habitats. In summary, this dissertation sheds light on the pervasive effects of temperature, substrate availability, and habitat type on these metabolic processes that are critical for the cycling of carbon and sulfur in deep sea hydrothermal vent sediments.

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39

Tcyrulnikov, Nikolai. "Pyridinium Salts: from Photoinduced Through-Space Electron Delocalization to Novel Spontaneous Reactions Causing Thermal DNA Damage." Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1561743270676153.

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40

Feltham, Emma Jane. "A matrix-isolation study of alkene oxidation reactions of atmospheric interest." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314317.

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41

鄧文偉 and Man-wai Simon Tang. "Novel cyclic ketones for catalytic epoxidation of olefins." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B31214654.

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42

葉耀宗 and Yiu-chung Yip. "Asymmetric epoxidation of unfunctionalized olefins catalyzed by chiralketones." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B31236406.

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43

黃文健 and Man-kin Wong. "Design and synthesis of chiral ketones for catalytic asymmetric epoxidation of unfunctionalized olefins." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B31236285.

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44

Leanord, Donald Robert. "A study of the oxidation of alkenes catalysed by polymer supported iron porphyrins." Thesis, University of York, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329654.

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45

余永耀 and Wing-yiu Yu. "Oxidation chemistry of cis-dioxoosmium (VI) and Ruthenium-Oxo complexes bearing a C2 symmetry chelating ligand." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1993. http://hub.hku.hk/bib/B31234008.

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Cavallaro, F. "Micro porous-based catalysts for selective oxidation reactions and isomerisation of alkanes." Thesis, Queen's University Belfast, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426967.

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47

Cooke, Paul Richard. "The oxidation of alkenes catalysed by polymer supported metalloporphyrins." Thesis, University of York, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333743.

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Yu, Eileen Hao. "Development of direct methanol alkaline fuel cells." Thesis, University of Newcastle Upon Tyne, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289171.

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49

何麗薇 and Lai-mei Ho. "Asymmetric epoxidation of olefins catalyzed by chiral iminium salts generated in situ from amines and aldehydes." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31226048.

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Cowell, J. J. "New avenues in alkene epoxidation : selective oxidation on Cu{111} and Cu{110}." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.598086.

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This work investigated the partial oxidation reactions of styrene on Cu{110} and Cu{111} and butadiene on Cu{111}. For the first time it has been shown that it is possible to epoxidise alkenes over single crystal copper surfaces, the reaction is not confined to silver alone. The techniques used included temperature programmed reaction spectroscopy (TPRS), auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), near edge X-ray absorption fine structure (NEXAFS) and scanning tunnelling microscopy (STM). The work described in this dissertation involves the adsorption of styrene onto the Cu{111} and Cu{110} surfaces modified with oxygen and caesium. The styrene adsorbed flat on the surface and reacted with partially oxidised copper to give styrene epoxide at very high selectivity. Fully oxidised surfaces were found to be inactive to styrene epoxidation, the alkene desorbs without reacting and with no change in geometry. The change in reactivity is due to changes in the intrinsic surface properties rather than a change in the styrene bonding. The process does not appear to be desorption rate limited, there is no evidence for the long term residence of styrene epoxide on the copper surface, suggesting that the reaction is reaction rate limited. Caesium reduced the surface oxidation, reducing oxidised copper to give bare copper and caesium oxides. This was accompanied by an increase in the activity of styrene epoxidation without adversely effecting selectivity, this is directly the opposite behaviour to caesium on silver. Studies involving butadiene showed the same basic behaviour. Partially oxidised Cu{111} epoxidises butadiene to epoxybutene at high selectivity. No other side chain products were observed, unlike the case on silver. Caesium was found to increase the activity of this reaction, resulting in almost 100% conversion. Work was conducted to enhance the resistance of the surface to over oxidation, nitroxy species were found to have little effect due to the formation of surface nitrites not nitrates.

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Dissertations / Theses on the topic 'Alkane Oxidation'

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