Дисертації з теми "Olefin oxidation"
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Javadekar, Ashay Dileep. "Surface science studies of olefin oxidation on the silver surface." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 131 p, 2009. http://proquest.umi.com/pqdweb?did=1889838931&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Повний текст джерелаHamidi, A. "Interaction between hindered piperidine light stabilisers and antioxidants in the thermal and photochemical oxidation of polyolefins." Thesis, Manchester Metropolitan University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378064.
Повний текст джерелаTownsend, Erik Matthew. "High-oxidation-state molybdenum and tungsten monoalkoxide pyrrolide alkylidenes as catalysts for olefin metathesis." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/91116.
Повний текст джерелаCataloged from PDF version of thesis. Vita.
Includes bibliographical references.
Chapter 1 describes work toward solid-supported W olefin metathesis catalysts. Attempts to tether derivatives of the known Z-selective catalyst W(NAr)(C₃H₆)(pyr)(OHIPT) (Ar = 2,6- diisopropylphenyl, pyr = pyrrolide; HIPT = 2,6-bis-(2,4,6-triisopropylphenyl)phenyl) to a modified silica surface by covalent linkages are unsuccessful due to destructive interactions between W precursors and silica. W(NAr)(C₃H₆)(pyr)(OHIPT) and W(NAr)(CHCMe₂Ph)(pyr)(OHIPT-NMe₂) (HIPT-NMe 2 = 2,6-bis-(2,4,6-triisopropylphenyl)-4- dimethylaminophenyl) are adsorbed onto calcined alumina. W(NAr)(C 3H6 )(pyr)(OHIPT) is destroyed upon binding to alumina, while W(NAr)(CHCMe 2Ph)(pyr)(OHIPT-NMe 2) appears to bind through a non-destructive interaction between the dimethylamino group and an acidic surface site. The heterogeneous catalysts perform non-stereoselective metathesis of terminal olefins, and W(NAr)(CHCMe₂Ph)(pyr)(OHIPT-NMe₂) can be washed off the surface with polar solvent and perform solution-phase Z-selective metathesis. Chapter 2 details selective metathesis homocoupling of 1,3-dienes with Mo and W monoalkoxide pyrrolide (MAP) catalysts. A catalytically relevant vinylalkylidene complex, Mo(NAr)(CHCHCH(CH₃)₂)(Me₂pyr)(OHMT) (HMT = 2,6-bis(2,4,6-trimethylphenyl)phenyl; Me₂pyr = 2,5-dimethylpyrrolide), is isolated. A series of Mo and W MAP catalysts is synthesized and tested for activity, stereoselectivity, and chemoselectivity in 1,3-diene metathesis homocoupling. Catalysts containing the OHIPT ligand display excellent selectivity in general, and W catalysts are less active but more selective than their Mo counterparts. Chapter 3 recounts the synthesis and characterization of several heteroatom-substituted alkylidene complexes with the formula Mo(NAr)(CHER)(Me₂pyr)(OTPP) (TPP = 2,3,5,6- tetraphenylphenyl; ER = OPr, N-pyrrolidinonyl, N-carbazolyl, pinacolborato, trimethylsilyl, SPh, or PPh2). Synthesis proceeds via alkylidene exchange between Mo(NAr)(CHR)(Me₂pyr)(OTPP) (R = H, CMe₂Ph) and a CH₂CHER precursor. Each complex behaves similarly to known MAP complexes in olefin metathesis processes; the electronic identity of ER has little effect on catalytic properties. Distinctive features of alkylidene isomerism and catalyst resting state are examined. Chapter 4 contains synthetic and catalytic studies of thiolate-containing Mo and W imido alkylidene complexes. The species M(NAr)(CHCMe 2Ph)(pyr)(SHMT) (M = Mo or W), Mo(NAr)(CHCMe₂Ph)(Me₂pyr)(STPP), and Mo(NAr)(CHCMe₂Ph)(STPP)₂ are synthesized by substitution of the appropriate thiol or thiolate ligands for pyrrolide or triflate ligands in metal precursors. These complexes show similar structural and spectral characteristics to alkoxidecontaining species. The thiolate complexes and their alkoxide analogues are compared for activity and selectivity in metathesis homocoupling and ring-opening metathesis polymerization processes. In general, thiolate catalysts are slower and less selective than alkoxide catalysts.
by Erik Matthew Townsend.
Ph. D.
Flook, Margaret McGuigan. "Z-selective olefin metathesis processes and Cis/syndioselective ROMP with high oxidation state molybdenum alkylidenes." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/73354.
Повний текст джерелаVita. Cataloged from PDF version of thesis.
Includes bibliographical references.
Chapter 1: Reaction of W(CCMe3)Cl 3(dme) with one equivalent of (3,5-Me 2C6H3NCH2CH 2)3N)Li3 affords yellow, crystalline W(CCMe3)(N3N) in good yield. The reactivity of this new alkylidyne complex towards terminal alkynes was investigated. Two other new tungsten alkylidynes, W(CCMe3)(pyr) 3 (pyr = 2,5-dimethylpyrrolide) and W(CCMe3)(Ph 2N)3 were prepared by the addition of three equivalents of lithium dimethylpyrrolide or lithium diphenylamide, respectively, to W(CCMe3)Cl 3(dme). The reactivity of these new alkylidynes with various alcohols is reported. The reactivity of several tungsten alkylidyne compounds towards ligand displacement by surface silanols is reported, resulting in the synthesis of several new silicasupported tungsten alkylidynes. The alkyne metathesis activity of all new homogeneous and heterogeneous alkylidyne complexes is reported. Chapter 2: Addition of one equivalent of 2,4,6,2',4',6'-hexaisopropylterphenol to Mo(NAd)(CHCMe 2Ph)(pyr)2 results in the formation of Mo(NAd)(CHCMe 2Ph)(pyr)(HIPTO) (HIPTO = hexaisopropylterphenoxide). This new alkylidene compound was found to catalyze the metathesis of 1-hexene in 20% yield to 95% cis 5-decene, which represents the first report of highly Z-selective metathesis homocoupling of a terminal olefin. The decomposition of the catalyst in the presence of ethylene is explored. The syntheses of several new bulky achiral phenoxide ligands are presented, along with the syntheses of the corresponding MAP (monoalkoxide monopyrrolide) molybdenum imido alkylidene compounds. The reactivity of new MAP compounds containing bulky phenoxide ligands towards the Z-selective metathesis of terminal and internal olefins is presented. The cis-selectivity of this system is proposed to arise from the combination of a relatively small imido ligand in conjunction with a very bulky alkoxide forcing the substituents of the substrate to point in this same direction with each insertion. Photolysis of MAP compounds with 366 nm radiation was found to produce significant amounts of anti alkylidenes, and the kinetics of decay of unstable anti alkylidenes are investigated. Chapter 3: The reaction of 2,3-dicarbomethoxynorbomadiene (DCMNBD) with Mo(NAd)(CHCMe 2Ph)(pyr)(HIPTO) (Ad = 1-adamantyl, HIPTO = hexaisopropylterphenoxide) affords >98% cis, >98% tactic polyDCMNBD. The tacticity of this polymer is proved to be syndiotactic through polymerization of DCMenthNBD (2,3-dicarbomenthoxynorbomadiene) and IH- H COSY. A variety of related MAP alkylidene compounds are also investigated towards the ROMP of DCMNBD and found to produce polyDCMNBD in a range of tacticities and cis contents. Highly cis polyNBDF6 (poly-bis(CF 3)-norbomadiene) was also prepared using molybdenum MAP compounds, and the resulting polymer was found to be essentially insoluble in common organic solvents. Solid state CPMAS 13C NMR spectroscopy revealed insoluble polyNBDF6 to be highly tactic, and the tacticity is proposed to be syndiotactic. Cis, tactic polymer was prepared through the addition of 3,3-methylphenylcyclopropene (MPCP) to molybdenum MAP compounds. Attempts towards determination of the tacticity of cispolyMPCP are presented, including the synthesis of three 3,3-disubstituted cyclopropene monomers containing chiral tags. The cis-selective ROMP of cyclooctene and 1,5- cyclooctadiene are reported. The syndioselectivity of the catalysts is proposed to be controlled by the configuration of the 4-coordinate metal center, which alternates with each insertion of monomer. Chapter 4: Racemic 2,3-dicarbomethoxynorbornene (rac-DCMNBE) is polymerized by Mo(NAd)(CHCMe 2Ph)(pyr)(HMTO) (Ad = 1-adamantyl, pyr = pyrrolide, HMTO = hexamethylterphenoxide) to afford an all-cis polymer that is syndiotactic and composed of alternating enantiomers. The cis, syndiotactic ROMP of several other racemic chiral monomers are reported, also affording structures containing a high degree of enantiomer alteration. Attempts towards the alternating copolymerization of two different monomers are reported. The ROMP of enantiomerically pure (+)-dicarbomethoxynorbornene with Mo(NAd)(CHCMe 2Ph)(pyr)(HIPTO) leads to the production of 92% trans-isotactic polyDCMNBE. The structure of trans-isotactic polyDCMNBD is proved through hydrogenation and comparison of its 3C NMR spectrum with that of known cis-isotactic polyDCMNBE. Both cis/syndiotactic/alternating poly-rac-DCMNBE and trans/isotactic poly-(+)-DCMNBE are polymer structures that have not been previously reported. The thermal properties of all new polymers and their hydrogenated counterparts are reported and are found to correlate closely with polymer structure.
by Margaret McGuigan Flook.
Ph.D.
Ackerman, Lily Joy Grubbs Robert H. Bercaw John E. "Ancillary ligand effects in niobocene olefin hydride complexes and hydrocarbon oxidation by palladium(II) complexes /." Diss., Pasadena, Calif. : California Institute of Technology, 2003. http://resolver.caltech.edu/CaltechETD:etd-05212003-130334.
Повний текст джерелаGardan, Martino. "Innovative catalytic processes for oxidation reactions." Doctoral thesis, Università degli studi di Padova, 2009. http://hdl.handle.net/11577/3426141.
Повний текст джерелаLo studio e lo sviluppo di sistemi metallo-catalizzati innovativi per l’ossidazione di molecole organiche con ossidanti sostenibili, specialmente ossigeno molecolare, O2, o acqua ossigenata, H2O2, è una prospettiva di grande attrazione per l’Industria Chimica. Nel progetto di Tesi di Dottorato, sono state sviluppate diverse strategie allo scopo di effettuare trasformazioni ossidative di riferimento quali l’autoossidazione di derivati benzilici, l’idrossilazione di idrocarburi aromatici e l’epossidazione di olefine. In tutti i casi, l’approccio alla ricerca si è basato su alcuni aspetti chiave che prevedono l’utilizzo integrato di: i) ossidanti a basso impatto ambientale quali O2 e H2O2; ii) catalizzatori multi-metallici ad elevata resistenza termica, idrolitica ed ossidativa; iii) tecniche di catalisi eterogenea per mezzo di materiali funzionali ibridi organici-inorganici costituiti da membrane catalitiche a matrice polimerica e protocolli che non prevedano l’impiego di solventi organici; iv) microonde o radiazioni fotochimiche quali tecniche di attivazione non convenzionali; v) tecniche di catalisi multipla con processi sequenziali e/o paralleli (Tandem Catalisi). I catalizzatori impiegati appartengono alla classe degli ossidi polianionici metallici, detti poliossometallati (POMs), aventi formula generale [XxMmOy]q-, dove M è il componente metallico principale (Mo, V, W) e X è un eventuale eteroatomo (P o Si). Questi complessi sono molto vantaggiosi come catalizzatori perché di natura inorganica, resistenti e sono modulabili in termini di struttura, composizione chimica, densità elettronica e carica polianionica. Particolarmente interessante è la possibilità di funzionalizzare la porzione inorganica con domìni di natura organica, potendo così ottenere catalizzatori ibridi organici-inorganici dalle prestazioni catalitiche migliori. Poiché le fasi fluorurate sono di particolare interesse per ciò che concerne le trasformazioni ossidative, l’attività di ricerca si è focalizzata sulla sintesi, caratterizzazione e attività catalitica di nuovi poliossometallati fluorurati. Sono state seguite due strategie di sintesi differenti basate sulla metatesi di controcatione e sulla funzionalizzazione covalente di superfici di POM inorganici. Con la prima strategia è stato isolato il polianione decatungstato (W10O32)4- con un controcatione tetraalchilammonio fluorurato ottenedo il sale fluorofilico ?[CF3(CF2)7(CH2)3]3CH3N}4W10O32 , (RfN4W10). Il decatungstato è noto per la sua capacità di essere iniziatore di processi radicalici se fotoirradiato in atmosfera di ossigeno. L’ossidazione fotocatalitica di etilbenzene ed altri idrocarburi benzilici tramite RfN4W10 e O2 è stata condotta in 1,1,1,3,3,3-hexafluoroisopropanolo (HFIP), sia in omogeneo che in fase eterogenea. L’applicazione della tecnologia delle membrane per la catalisi eterogenea offre, in particolare, numerosi vantaggi in termini di combinazioni di avanzati processi di separazione molecolare con proprietà di trasporto selettive, insieme alla reattività su supporti solidi. L’eterogeneizzazione del fotocatalizzatore è stata così ottenuta per incorporazione di RfN4W10 in film polimerici perfluorurati di HYFLON AD 60X, ottenendo così nuovi materiali ibridi da impiegare e reciclare in processi “multi-turnover” ed in assenza di solventi. Immagini di microscopia elettronica a scansione (SEM) della superficie e della sezione del film evidenziano una distribuzione omogenea ed altamente dispersa dei domini catalitici che appaiono come particelle sferiche a dimensioni uniformi e di diametro pari a circa 2-3 ?m. Inoltre, in condizioni controllate, è stato possibile ottenere una membrana porosa da poter utilizzare in un reattore a flusso continuo. Nelle condizioni testate, la fotoossigenazione con (RfN)4W10O32 dà benzilidroperossido ed il corrispondente alcool e chetone. E’importante evidenziare come la fotoossigenazione di tetralina ed indano proceda con TON>6000 e con una elevata selettività in alcool, fornendo così un’ importante alternativa ad altri sistemi di ossigenazione basati su meccanismi di tipo radicalico. Poliossometallati fluorurati sono stati sintetizzati anche tramite l’approccio di funzionalizzazione covalente. Questa strategia prevede l’impiego di poliossotungstati lacunari e organosilil cloruri CF3(CF2)7CH2CH2SiCl3 (RfSiCl3) a dare derivati ibridi per mezzo dell’attacco covalente dei gruppi organici sulla superficie del POM. I complessi finali risultanti, con formula generale Q4[(RfSi)xOySiWwOz], isolati come sali di tetrabutilammonio (Q+) sono stati caratterizzati ed impiegati come catalizzatori per l’epossidazione di diverse olefine in presenza di H2O2. Studi cinetici e meccanicistici hanno fornito diverse indicazioni circa l’esistenza di un effetto sinergico fra i catalizzatori e il solvente per fluorurato utilizzato (HFIP). E’importante sottolineare come questa reazione attivata da microonde produca epossido in rese quantitative dopo soli 20 minuti anche per le olefine terminali. Ulteriori aspetti trattati riguardano le caratteristiche auto-assemblanti di questi complessi fluorurati anfifilici. Fenomeni di aggregazione in soluzione di HFIP sono stati studiati tramite DLS e tramite microscopia elettronica allo stato solido. Anche l’eterogeneizzazione di questo sistema è stata ottenuta tramite l’approccio di funzionalizzazione covalente. In questo caso, il poliossotungstato lacunare è stato fatto reagire con un silano che porta una catena alchilica insatura terminale: CH2=CH(CH2)6SiCl3 (RSiCl3). La morfologia e la struttura del materiale ibrido risultante sono state modulate attraverso la variazione del rapporto dei solventi porogenici e dei comonomeri impiegati nella miscela di polimerizzazione. Il polimero ibrido finale presenta l’interessante proprietà di rigonfiare in alcool fluorurati, dove l’epossidazione di cis-cicloottene avviene con rese quantitative in 15 minuti. Infine, è stato studiato il processo POM-catalizzato per la sintesi di fenolo: uno degli intermedi e commodity a più alto valore di mercato. A questo scopo l’attività di ricerca è stata incentrata sullo studio sia del processo autoossidativo, sia della mono-idrossilazione diretta del benzene. (i) L’applicazione di tecniche di Tandem Catalisi, allo scopo di sfruttare la produzione con sistema a membrana foto catalitica del cumilidroperossido da cumene, e promuoverne la sua decomposizione a fenolo in un secondo stadio con un catalizzatore POM-acido, (ii) lo screening di diversi molibdovanadati come catalizzatori da usare con H2O2 per l’idrossilazione di benzene. Nel primo caso, la Tandem Catalisi permette di ottenere una resa in fenolo pari a 63% rispetto alle moli iniziali di cumilidroperossido, nel secondo caso, con H4Mo11VO40 si ha un miglioramento dei dati di letteratura per ottimizzazione della reazione con 17% di conversione, selettività = 90% e TOF = 22.5 h-1.
Shrestha, Sweta. "Application of Transition Metal Coordination for Energy Efficient Processes: Catalysis and Separation." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1502975499629018.
Повний текст джерелаAxtell, Jonathan Clayton. "Synthesis and reactivity of high oxidation state tungsten and molybdenum olefin metathesis catalysts bearing new imido ligands." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98598.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references.
Chapter 1 details the synthesis of tungsten imidoalkylidene compounds bearing strongly electron-withdrawing imido ligands. An alternative synthesis involving the treatment of WCl6 with 4 equivalents of N-trimethylsilyl-substituted anilines and subsequent workup with 1,2-dimethoxyethane (DME) has been employed to form complexes of the type W(NAr)2C12(dme); syntheses employing WO2C 2(dme) as the tungsten precursor were unsuccessful. Alkylation with neopentylmagnesium chloride (ClMgNp) and subsequent treatment with trifluoromethanesulfonic acid (HOTf) affords imidoalkylidene species W(NAr)(CHCMe 3)(OTf)2(dme) (OTf = trifluoromethanesulfonate); analogous neophylidene ([W]CHCMe 2Ph) species could not be made under these conditions. Treatment of these compounds with two equivalents of LiO(2,6-(CHCPh 2)C6H3)-Et2O affords the bisaryloxide complexes of the type W(NAr)(CHCMe3)(OR)2. Ring-Opening Metathesis Polymerization (ROMP) studies using a series of these bisaryloxides show that rates of ROMP increase as the electron-withdrawing power of the substituents on the imido ligand increase if steric bulk about the metal center is held constant. A similar trend between two bisaryloxides is observed for anti-to-syn alkylidene rotation rates at 50*C in toluene-d8 . Difficulties synthesizing bis-pyrrolide complexes of the type W(NAr)(CHCMe3)(pyr)2 precluded their use as catalyst precursors; some MAP species containing the more sterically encumbering 2,5-dimethylpyrrolide ligand are presented and the metathesis activity of MAP species bearing the 2,5-dimethylpyrrolide ligand is discussed. Chapter 2 introduces Mo and W complexes bearing the current extreme in sterically bulky imido ligands, the NHIPT (HIPT = 2,6-(2,4,6-iPr 3CH2)CH3) ligand, in an effort to generate all anti alkylidene species. A non-traditional synthetic route is employed in order to install this ligand first as an anilide, and after subsequent proton transfer, as an imido ligand to form a mixed imido species of the type M(NHIPT)(N'Bu)(NH'Bu)Cl. Addition of one equivalent of 2,6-lutidinium chloride, followed by alkylation affords dialkyl species M(NHIPT)(N'Bu)Np 2, and treatment with three equivalents of pyridinium chloride yields all anti imidoalkylidene dichloride species as mono-pyridine adducts, M(NHIPT)(CHCMe 3)C 2(py) (M = Mo, W). General reactivity, including strategies for removal of the pyridine adduct as well as substitution and metathesis chemistry, are discussed. ROMP of MPCP (MPCP = 3-methyl-3-phenylcyclopropene) by a Mo-based MAP species bearing the NHIPT ligand yields predominantly cis,syndiotactic poly(MPCP) and in the homo-metathesis of 1 -octene yields ~81% cis-7-tetradecene. The possible source of trans olefinic product is addressed. Chapter 3 presents the synthesis of the first (1-adamantyl)imido species of tungsten. The functional equivalent of common bisimido precursors for other Mo/W alkylidene species, [W(NAd) 2C 2(AdNH2)1 2, is shown to be a dimer stabilized by hydrogen-bonding interactions between adamantylamine protons and adjacent chlorides bound to the second metal of the dimer. Subsequent alkylation with ClMgNp affords the expected dialkyl species, and treatment with three equivalents of 3,5-lutidinium chloride affords imidoalkylidene complex W(NAd)(CHCMe 3)(C) 2(lut)2 (lut = 3,5-dimethylpyridine). The most desirable synthetic route toward monoalkoxide pyrrolide (MAP) species proceeds through a monoaryloxide monochloride intermediate W(NAd)(CHCMe 3)(Cl)(OAr)(lut) (Ar = 2,6-(2,4,6-Me 3)C6H3, 2,6-(2,4,6-'Pr 3)C6H3). Removal of lutidine with B(C6 F5 )3 and subsequent treatment with lithium pyrrolide affords W(NAd)(CHCMe3)(pyr)(OAr) (pyr = pyrrolide); 2,5-dimethylpyrrolide analogues (W(NAd)(CHCMe3)(Me2pyr)(OAr) can be accessed via protonolysis by HOAr from W(NAd)(CHCMe3)(Me2pyr)2(lut).
by Jonathan Clayton Axtell.
Ph. D.
Tsang, W. C. Peter 1975. "High oxidation state molybdenum and tungsten imido alkylidene and metallacycle chemistry : catalytic asymmetric olefin metathesis and mechanistic investigation." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/30064.
Повний текст джерелаVita.
Includes bibliographical references.
Enantiomerically pure molybdenum imido alkylidene complexes of the type Mo(NAr)(CHCMe₂Ph)[Ar'](THF), which contained 3,3'-diaryl (Ar' = Mes (21), Ph (22)) substituted binaphtholate ligands, were prepared and structurally characterized. Complex 21 was a trigonal bipyramidal anti alkylidene complex; both 21 and 22 were anti-THF adducts. Temperature and concentration dependent enantioselective desymmetrization of prochiral trienes by catalyst 21 afforded five- and six-membered heterocycles in >90% conversion and >90% ee. Consumption of the six-membered substrate followed pseudo first-order kinetics. The new catalyst was compatible with a variety of common functional groups. The longevity of the catalysts depended on the concentration of ethylene in solution. The resting state of the catalytic cycle, unsubstituted molybdacyclobutane 70, slowly decomposed to yield propylene. This observation suggests that β-hydride elimination can compete with bimolecular coupling of methylene complexes under some conditions. Chapter 2: Racemic and enantiomerically pure tungsten imido alkylidene complexes, W(NAr)-(CHCMe₂Ph)(Biphen) (23a, Ar = 2,6-i-Pr₂C₆H₃) and W(NAr')(CHCMe₂Ph)(Biphen) (23b, Ar' = 2,6-Me₂C₆H₃) were prepared and shown to be viable catalysts for representative asymmetric ring- closing metathesis reactions. Both catalysts were compatible with a variety of common functional groups. Intermediate tungstacyclobutane complexes were observed when a stoichiometric amount of desymmetrization substrate 62 was added to 23a. The final stable complex 78, formed between the ring-closed product and a tungsten methylene complex, was structurally characterized. Isotopic labeling experiments with ¹³C₂H₄ allowed the observation of
(cont.) unsubstituted tungstacyclobutane complexes (82), ethylene complexes (84), tungstacyclopentane complexes (86), and a heterochiral methylene dimer (85a). The tungstacyclopentane complexes catalyzed slow dimerization of ethylene to 1-butene. The observation of the methylene dimer provides the first direct evidence of a bimolecular decomposition pathway for methylene complexes. Chapter 3 Racemic and enantiomerically pure molybdenum alkylimido alkylidene complexes, Mo(NAd)(CHCMe₂Ph)(Biphen) (19d, Ad = 1-adamantyl) and Mo(NAd)(CHCMe₂Ph)[Trip]-(THF) (20d) were prepared and structurally characterized. Complex 19d was observed almost exclusively as a syn alkylidene isomer, in contrast with 20d which was observed almost exclusively as an anti-THF adduct. Complexes 19d and 20d are the only reported chiral alkylimido alkylidene complexes for enantioselective olefin metathesis reactions. Complex 19d is the first crystallographically characterized four-coordinate adamantylimido alkylidene complex in its base-free form. It offers unique reactivity and selectivity profiles in tandem AROM/RCM and AROM/CM reactions. Complex 19d is compatible with a variety of common functional groups, including boron-containing reagents. Van't Hoff analyses suggest that the bias toward syn-19d isomer is entropy-driven. Chapter 4: Solvent- and base-free molybdenum methylene complexes, Mo(NAr)(Biphen)(CH₂) (114a, Ar = 2,6-i-Pr₂C₆H₃) and Mo(NAd)(Biphen)(CH₂) (114d, Ad = 1-adamantyl) ...
by W.C. Peter Tsang.
Ph.D.
Sen, Suman [Verfasser], and Michael R. [Akademischer Betreuer] Buchmeiser. "High oxidation state N-heterocyclic carbene molybdenum alkylidene complexes : functional-group tolerant olefin metathesis catalysts / Suman Sen ; Betreuer: Michael R. Buchmeiser." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2016. http://d-nb.info/1118371305/34.
Повний текст джерелаAnsaloni, Simone. "Oxidative properties of the Iron - Thymine-1-acetic acid - Hydrogen peroxide catalytic system." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/4937/.
Повний текст джерелаMeng, Xiangtao. "Chemical Modification of Cellulose Esters for Oral Drug Delivery." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/71383.
Повний текст джерелаPh. D.
Borrell, Recasens Margarida. "Small-molecule mimics of rieske oxygenases. Application to selective aliphatic C-H hydroxylation and olefin syn-dihydroxylation." Doctoral thesis, Universitat de Girona, 2021. http://hdl.handle.net/10803/673107.
Повний текст джерелаLes reaccions d’oxidació tradicionalment es realitzen utilitzant oxidants estequiomètrics que generen una gran quantitat de residus. La sin-dihidroxilació d’alquens n’és un exemple paradigmàtic perquè és una reacció que es pot considerar pedra angular en síntesi orgànica, i actualment encara es porta a terme amb oxidants basats en metalls pesats, especialment òxids d’Os i Ru en quantitats catalítiques, però també KMnO4, en quantitats estequiomètriques. L’acetonitril i els dissolvents halogenats són dissolvents àmpliament utilitzats en aquestes reaccions per la seva naturalesa robusta en vers les oxidacions. No obstant això, les oxidacions catalitzades per metalls en dissolvents menys tòxics són bàsicament desconegudes. Les oxigenases de Rieske, són enzims de ferro no hemo que catalitzen la sin-dihidroxilació d’olefines entre altres reaccions. És ben sabut que les espècies de FeV(O)(OH) tenen un paper clau com a intermediaris en la di hidroxilació d’arens catalitzada per les oxigenases de Rieske. No obstant això, la incapacitat per acumular aquests intermedis en solució a impedit, fins ara, la seva caracterització espectroscòpica i química. En aquesta tesi, vam ser capaços de sintetitzar un catalitzador de ferro amb un lligand tetradentat estèticament impedit. La demanda estèrica del lligand es va concebre com un element clau per donar suport a una alta activitat catalítica evitant camins de descomposició bimoleculars i facilitant l’alliberament del producte, proporcionant rendiments entre bons i excel·lents del producte sin-diol (fins a un 97% de rendiment aïllat) per una àmplia gamma d’olefines
Programa de Doctorat en Química
Klauber, David J. "Development of novel olefin oxidations." Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491271.
Повний текст джерелаS, Suresh. "Studies On Oxidation Of Benzylidene Derivatives." Thesis, Indian Institute of Science, 1994. http://hdl.handle.net/2005/151.
Повний текст джерелаJunior, Luiz Fernando da Silva. "Reações de contração de anel promovidas por sais de tálio (III)." Universidade de São Paulo, 1999. http://www.teses.usp.br/teses/disponiveis/46/46135/tde-25052007-151439/.
Повний текст джерелаThis thesis presents studies toward the ring contraction of ketones and olefins promoted by thallium(III) The reaction of alkylcyclohexanones and cis and trans-2-decalones with TTN in CH2Cl2 led to the corresponding ring contraction products in very good yields, providing there is no methyl group at α-carbonyl position. The reaction of 3- and 4-alkylcyclohexanones, as well as trans-2-decalones, occurred with high degree of selectivity. The observed diastereoselectivities agree with the McKillop\'s mechanism. The indan ring system was constructed by three different protocols. The reaction of 1-tetralones with TTN/K-10 in pentane afforded methyl 1-indanecarboxylates in reasonable yields, while treatment of 1,2-dihydronaphathlenes with TTN in MeOH furnished the corresponding ring contraction products in good yields, as long as there is no alkyl group at the double bond. Finally, the reaction of two homoallylic alcohols, bearing an endocyclic double bond, with TTN in a 1:1 mixture of AcOH and H2O, led to 1-(2,3-dihydro-1H-1-indenyl)-3-hydroxypropan-1-ones in excellent yields.
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.
Повний текст джерела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.
Повний текст джерелаZhang, Chi. "Studies on epoxidation of olefins by IN SITU generated N-sulfonyloxaziridine and ruthenium catalyzed oxidative cleavage of olefins." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22718667.
Повний текст джерелаAbada, Zahra. "Synthèse de porphyrines chirales : application en oxydation asymétrique et application antiparasitaire et anticancéreuse." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA114806.
Повний текст джерелаChiral molecules represent about 60% of drugs in pharmaceutical market and over 80% of drugs in development with more than 150 billion dollars in 2002. Chiral intermediates are in high demand in the pharmaceutical industry producing a turnover of 15 billion dollars in 2009. Other areas are seekers of chiral molecules with a distribution of about 15% in agrochemicals and 5% for the perfume. Asymmetrically production of compounds of pharmaceutical interest is a real challenge. These molecules have a spatial architecture that results in specific interactions and affinity with the enzymes or biological chiral receptors. The use of catalysts to synthesis chiral organic compounds, and more specifically to oxidize alkenes and alkanes having prochiral positions, is a very important area extensively studied in recent decades with few positive results. To achieve the synthesis of chiral molecules, the pharmaceutical industry has turned to the use of biocatalysts, in part, to perform various stereo-controlled reactions with systematically followed by separation of the different isomers by different methodes. However, biocatalysts have a major disadvantage relative to low yields of chiral compound and requires expertise for handling these enzymes. Metalloporphyrins are tetrapyrrolic macrocyle substituted in meso position with various functional groups and incorporating metals (Fe, Mn, Co, Ru). These molecules have been extensively studied and led to the synthesis of many complex chiral metalloporphyrins. Unfortunately, their synthesis is often long with low yields and their application to a limited number of substrates is a major drawback. The first objective of this work is the synthesis of original chiral porphyrins. The targeted structure contains chiral heterocyclic nitrogen groups in two meso positions, connected by a carbon-heteoatom bond (C-N). We were able to reach 4 porphyrins-series that have been evaluated as catalyst in oxidation reactions (epoxidation, hydroxylation). The second objective is to take advantage of specific electronic properties of porphyrins for applications as photosensitizer after photoactivation for cancer by photodynamic therapy. The use of this therapy increased during last decades but poor specificity and solubility of the different porphyrins used in clinic against many cancers prompt us to investigate this area. The study of the physical parameters is essential to determine wavelength activation and quantum yield of a photosensitizer. We wanted to use our porphyrins and their precursors as antiparasitic agents, with and without photoactivation against L. donovani, L. major, T. brucei brucei. Malaria is caused by a protist of the genus of Plasmodium. This parasite has an iron deficiency on one hand and cannot biosynthesize certain amino acids. Strucure analogy of porphyrins with heme led us to evaluate antimalarial activity of several porphyrins against P. falciparum
McNamara, John Martin. "An evaluation of alumina suppoted platinum catalysts for the oxidative dehydrogenation of n butane." Thesis, University of Glasgow, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289903.
Повний текст джерелаCheck, Christopher. "Palladium-Catalyzed Inter- and Intramolecular Allylic Oxidation Reactions of Olefins." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1348618169.
Повний текст джерелаSchnobel, Michael. "Partial oxidation of α-olefins over iron antimony oxide catalysts". Doctoral thesis, University of Cape Town, 1997. http://hdl.handle.net/11427/22449.
Повний текст джерелаIron antimony oxide has been known to be an active and selective catalyst for the partial oxidation of propene to acrolein and the oxidative dehydrogenation of 1-butene to 1,3- butadiene. It has become the preferred catalyst for the industrial acrolein formation from propene. The main purpose of this work was to investigate the influence of catalyst parameters such as calcination temperature, Sb:Fe ratio, type of pre-treatment, absence or presence of gaseous oxygen on the activity and selectivity in the partial oxidation of propene. Furthermore the influence of the reaction parameters temperature, space time, partial pressure, time on stream and the carbon chain length of the olefin have been studied in partial oxidation reactions using a fixed bed U-tube glass reactor. Various models have been tested for the rate of formation of products in the range of C₂ to C₆ α-olefins. Increasing the calcination temperature from 500°C to 900°C resulted in an increase of the crystallite diameter and a simultaneous decrease of the surface area which might be ascribed to high temperature sintering of the catalyst. The activity decreased proportional to the decrease of surface area. At the same time the selectivity to acrolein increased with increasing calcination temperature.
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.
Повний текст джерелаChacon, J. N. "Dye photosensitised oxidation of oleic and linoleic esters." Thesis, University of the West of Scotland, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370167.
Повний текст джерела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.
Повний текст джерелаHo, Chun-yu, and 何振宇. "Asymmetric epoxidation of olefins and cyclization reactions catalyzed by amines." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B45014814.
Повний текст джерелаEndinkeau, K. "Oxidative and nonoxidative effects of ionising radiation on palm olein." Thesis, University of Salford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381823.
Повний текст джерелаZhang, Chi, and 張弛. "Studies on epoxidation of olefins by IN SITU generated N-sulfonyloxaziridine and ruthenium catalyzed oxidative cleavage ofolefins." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31242650.
Повний текст джерелаBELTRANI, MICHELA. "Oxidative Carbonylation of Unsaturated Substrates Promoted by Aryl [Alfa]-Diimine Pd(II) Complexes." Doctoral thesis, Urbino, 2015. http://hdl.handle.net/11576/2628805.
Повний текст джерелаAltun, Yasemin. "Addition Of Carbonyl Compounds To The Cyclic Olefins: Synthesis Of Cyclitols." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12610117/index.pdf.
Повний текст джерела#8211
CH2OH group in their structure. In this study, novel synthetic strategies leading to cyclitol derivatives were investigated and the synthesis of tetraol (72) and pentaol (73) derivatives containing &
#8211
CH2OH group were achieved successfully. Moreover, by the use of manganese(III) acetate oxidation reactions having considerable synthetic utilities in organic chemistry we developed new synthetic methodologies for the cyclitol derivatives. 1,3- and 1,4-Cyclohexadiene (71 and 10) were synthesized from easily available starting materials in order to be used as key compounds. The use of manganese(III) acetate oxidation reaction provides the creation of &
#8211
CH2OH group and one of the hydroxyl groups and the remaining hydroxyl groups were introduced into the key compounds by the use of singlet oxygen reaction. As a result of this, we had considerable advance in the synthesis of cyclitol derivatives.
Bazan, Guillermo C. (Guillermo Carlos). "Synthesis and reactivity of high oxidation state molybdenum catalysts for ring opening metathesis polymerization of olefins." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/13743.
Повний текст джерелаEl, Kadiri Moulay Youness. "Développement et évaluation de nouveaux systèmes catalytiques pour une chimie plus respectueuse de l'environnement." Phd thesis, Université Claude Bernard - Lyon I, 2012. http://tel.archives-ouvertes.fr/tel-00978594.
Повний текст джерелаBurcher, Benjamin. "Novel low-oxidation state iron complexes : reactivity towards unsaturated substrates." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAF022.
Повний текст джерелаIn this thesis our aim was to study the reactivity of phosphine-based low-valent iron complexes towards unsaturated substrates. This goal is part of a wider approach of access to an iron catalytic system able to transform ethylene in a selective manner, by the reaction of oligomerization, towards short linear alpha-olefins (1-butene, 1-hexene, 1-octene), which is unreported in the literature. To achieve this, going through the metallacyclic mechanism of ethylene transformation is the most likely way. However, the electronic and geometrical features of the ligand required to follow this mechanism, and in particular the key step of the oxidative coupling of two molecules of ethylene to the metal center, are ill-defined. We thus report here in a first part the synthesis of a library of P-based iron(II) and iron(III) complexes bearing varied electronic and geometrical features. These novel complexes are opportunistically screened as catalysts for ethylene oligomerization on one hand, and as in situ reduced species in association with dienes (isoprene, butadiene) leading to the polymerization of the latter substrates, on the other hand. In order to get closer to our goal of access to low-valent iron complexes, the use of a one-pot reduction methodology under mild conditions is reported, leading to the isolation and characterization of nine 18- and 16-electron iron(0) complexes. Even though they do not show reactivity towards ethylene or longer olefins, we demonstrate the ability of these complexes to promote reactions involving the oxidative coupling elementary step of unsaturated substrates (alkynes), the catalytic coupling of ethylene and butadiene and the activation of various compounds such as silanes and organic halides, representing a first milestone towards their optimization and application as catalysts for other reactions, including potentially in the near future, for ethylene transformation
Sparks, Darrell Lynn. "Oxidation of lipids in a supercritical-fluid medium." Diss., Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-03252008-162949.
Повний текст джерелаGonzalez, Sonia. "Oxidation and Textural Characteristics of Butter and Ice Cream with Modified Fatty Acid Profiles." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/34076.
Повний текст джерелаMaster of Science
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.
Повний текст джерелаRode, Katharina [Verfasser]. "Studies Toward Selenium-pi-Acid Catalyzed Oxidative Functionalizations of Olefinic and Acetylenic Multiple Bonds / Katharina Rode." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2020. http://d-nb.info/1218299258/34.
Повний текст джерелаChintalapudi, Kavyasree. "Development of Real-Time Electro-Organic Reaction Screening Platform Based on Nano-Electrospray Ionization Mass Spectrometry." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1523881317339198.
Повний текст джерелаWilhelm, Michael [Verfasser], Wolfgang A. [Akademischer Betreuer] Herrmann, and Janos [Akademischer Betreuer] Mink. "Ionic Catalysts for the Cycloaddition of Carbon Dioxide with Epoxides and the Oxidation of Olefins / Michael Wilhelm. Gutachter: Wolfgang A. Herrmann ; János Mink. Betreuer: Wolfgang A. Herrmann." München : Universitätsbibliothek der TU München, 2015. http://d-nb.info/1075858240/34.
Повний текст джерелаWilkerson, Troy A. "A comparative study of the thermal oxidative stability of high oleic acid sunflower and polyunsaturated soybean oil blends." Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-08222008-063712/.
Повний текст джерелаMachado, Yguatyara de Luna. "Avalia??o da estabilidade oxidativa e determina??o da cin?tica de oxida??o de ?leos vegetais, ?cido oleico e biodiesel utilizando o m?todo PetroOXY (ASTM D7545)." PROGRAMA DE P?S-GRADUA??O EM ENGENHARIA QU?MICA, 2014. https://repositorio.ufrn.br/jspui/handle/123456789/21671.
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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)
A Ag?ncia Nacional de Petr?leo, G?s Natural e Biocombust?veis tem como principal miss?o regulamentar e especificar toda a produ??o e comercializa??o do biodiesel produzido em territ?rio nacional. Para a sua comercializa??o ? necess?rio que o biodiesel passe por um controle r?gido de qualidade, bem como esteja devidamente especificado pelas principais normas. A estabilidade oxidativa que ? um dos par?metros incluso pela norma europ?ia EN 14214 vem adquirindo cada vez mais espa?o em pesquisas por estar intrinsecamente relacionada ? qualidade do biodiesel. Biodiesel ? uma mistura de ?steres alqu?licos de ?cidos graxos obtido, convencionalmente, atrav?s da rea??o de transesterifica??o de um ?leo vegetal ou gordura animal. No entanto, a natureza da mat?ria-prima a qual lhe dar? origem ? um dos fatores determinantes em seu grau de estabilidade, visto que por apresentarem insatura??es em n?mero e em distintas posi??es os tornam suscept?veis ao ataque do oxig?nio atmosf?rico e a condi??es de elevadas temperaturas proporcionando, assim, a sua degrada??o. Uma das principais problem?ticas enfrentadas, atualmente, pela ind?stria de biodiesel prov?m da sua baixa estabilidade levando a uma diminui??o de sua qualidade por longos per?odos de armazenamento sendo necess?ria a aplica??o de antioxidantes. Nesta tese, um estudo cin?tico experimental baseado no consumo de diferentes antioxidantes sint?ticos adicionados em distintas concentra??es foi realizado com amostras de ?leos vegetais de moringa (Moringa oleifera) e de maracuj? (Passiflora edulis), ?cido ol?ico estocado (AO) durante seis e dezoito meses e biodiesel de soja (Glycine max L.) e girassol (Helianthus annuus) em diferentes temperaturas, a uma press?o de oxig?nio puro a 700 kPa, utilizando a metodologia ASTM D7545 (PetroOXY). O modelo de primeira ordem obtido para o ?leo de moringa, amostras de ?cido ol?ico estocado (AO) e biodiesel de soja permitiu obter informa??es a respeito de par?metros, tais como: concentra??o cr?tica e concentra??o de antioxidante natural inerente ? amostra avaliada , informando que o ?ltimo n?o exerceu influ?ncia, a n?o ser inicialmente, no processo oxidativo das mesmas. Enquanto, o par?metro determinado para o modelo de ordem zero para as amostras de ?leo de maracuj? e girassol relacionou-se a diferentes reatividades da mat?ria-prima. A estabilidade das amostras determinadas pela entalpia de ativa??o (?HA) deu-se na seguinte ordem: ?HA (?leo de moringa) > ?HA (?leo de maracuj?); ?HA (AO 6 meses) ?HA (AO 18 meses) e ?HA (biodiesel de soja) > ?HA (biodiesel de girassol). Fatores de estabiliza??o desempenharam diferentes pap?is na estabiliza??o dos sistemas estudados. Concentra??o de antioxidante e temperatura mostraram distintas influ?ncias, no processo oxidativo, para as amostras de ?leos vegetais e ?cido ol?ico estocadas (AO) acompanhadas pelos seus ?ndices de acidez.
Oxidative stability is a parameter included in the European standard EN 14214 and is closely associated with the quality of biodiesel. The biodiesel is usually obtained in a transterification reaction vegetable oil or animal fat. However, the composition of the raw resources biodiesel is obtained from influences the stability degree of the latter, particularly when biodiesel is stored for long periods of time, causing its degradation, thereby reducing biodiesel quality and making it inadequate for trade. In this thesis, an experimental kinetic study based on the consumption of several synthetic antioxidants added in various concentrations to vegetable oils of moringa (Moringa oleifera), passion fruit (Passiflora edulis) and oleic acid (AO) stored for six and eighteen months at the temperatures 110 ?C, 120 ?C, 130 ?C and 140 ?C, as well as biodiesel from soybean (Glycine max L.) and sunflower (Helianthus annuus) oils at the temperatures 130 ?C, 135 ?C, 140 ?C and 145 ?C at a 700 kPa pure oxygen pressure, using the ASTM D7545 Method (PetroOXY). It has been obtained a first order reaction kinetic model for oleic acid, soybean biodiesel and moringa oil samples, while for passion fruit oil and sunflower biodiesel samples a zero order reaction kinetic model has been obtained. Parameter 0,CICCCC??? determined for the zero order model was related to distinct composition variations of the raw resources. The stability order of samples established using activation enthalpy (?HA) was the following: ?HA (moringa oil) > ?HA (Passion fruit oil); ?HA (oleic acid stored for six months) ? ?HA (oleic acid stored for eighteen months) and ?HA (soybean biodiesel) > ?HA (sunflower biodiesel). In all evaluated temperatures except for 140?C, acid numbers for passion fruit oil with antioxidants added have increased after storage, while for the moringa oil a random behavior has been observed.
Ferrari, I. "MODELLING THE PERFORMANCES OF TRADITIONAL AND INNOVATIVE FATS IN A PLUM CAKE FORMULATION." Doctoral thesis, Università degli Studi di Milano, 2012. http://hdl.handle.net/2434/169033.
Повний текст джерелаAl-Shudiefat, Abd Al-Rahman. "Protective role of olive oil and its major component oleic acid in TNF-α induced remodeling subsequent to myocardial infarction in rats". Springer, 2013. http://hdl.handle.net/1993/20074.
Повний текст джерелаBrechot, Philippe. "Oxycarbonylation des olefines en presence de nitrites d'alkyle catalysee par les complexes du palladium." Paris 6, 1988. http://www.theses.fr/1988PA066107.
Повний текст джерелаSavova, Bistra. "Étude du dopage de catalyseurs de déshydrogénation oxydante de l’éthane et du propane." Thesis, Lyon 1, 2009. http://www.theses.fr/2009LYO10341/document.
Повний текст джерелаThe oxidative dehydrogenations of propane and ethane have been studied on alkaline earth oxides doped with neodymium oxide (AEO) and nickel oxide doped with different metal oxides. Two types of synthesis have been compared for the preparation of AEO+Nd samples. The characterization by XRD showed the formation of solid solutions with different defects (cationic vacancies, dislocations). The formation of agglomerates of neodymium has also been observed. The catalytic testing showed that the presence of neodymium oxide increases both the conversion of propane and the selectivity to propylene. The addition of neodymium oxide increases the basicity of the catalysts, which seems to be beneficial to the selectivity. The nickel oxide based catalysts are very efficient in the oxidative dehydrogenation of ethane. The study shows that there is no formation of extended solid solution. The addition of niobium and oxalates anions leads to the isolation of the active O- sites at the surface of the nickel oxide, which decreases the activity but strongly increases the selectivity to ethylene. Furthermore, it modifies textural properties of nickel oxide increasing its specific surface area leading to better conversions. However, the applicability of this type of catalysts stays under question because of a deactivation that has been evidenced with time on stream. The characterization of the fresh and deactivated catalysts by XRD, Raman, XPS, TEM, EDX and TPD of O2 showed that this deactivation is due to the slow and irreversible reduction of Ni3+ cations leading to a further decrease in number of the O- species. The formation of NiNb2O6 phase during the deactivation has been evidenced
Duval, Maryne. "Ligands bidentes pour la synthèse de complexes de cuivre et d'or : étude de leur réactivité." Thesis, Toulouse 3, 2021. http://www.theses.fr/2021TOU30018.
Повний текст джерелаThis thesis focused on the synthesis of copper(III) complexes and the study of their reactivity toward the elementary steps induce in catalytic cycles of olefin oligomerization processes (migratory insertion, β-H elimination/transfer, isomerization, oxidative coupling). For this purpose, a methodology combining theoretical calculations and experimental tests was used.The first chapter of this thesis presents in general oligomerization of ethylene for the obtaining of linear α-olefin and explains the interest of using a copper catalyst from an industrial and fundamental point of view. According to the predictive theoretical calculations performed, the migratory insertion process in a Cu(III)–C bond seems more accessible than in a Cu(I)–C bond. The first lock of this thesis is therefore access to these copper(III) complexes.The second chapter gives a general overview of copper chemistry and its use in catalysis. In more depth, a bibliographic report on stable copper(III) complexes is reported in order to understand which criteria help stabilize this complexes. Copper(III) species being known to be very unstable, the experimental techniques used for the detection of these highly reactive species are also described. On the other hand, the known and stable organometallic copper(III) complexes are not suitable for the reactivity envisaged. Based on theoretical calculations as well as on the results previously obtained in the group on gold chemistry, two strategies described in chapters three and four, were considered to obtain a stable copper(III) complexes.The third chapter of this thesis deals with the first strategy for access to copper(III) complexes based on intramolecular C–I oxidative addition assisted by a chelate effect. Theoretical studies were carried out and the naphthylphosphine and naphthylamine peri-iodide ligands were chosen. C–Br, C–C and C–P couplings have been observed and allow to suppose a copper(III) intermediate. The original and unprecedented formation of a cyclic peri-bridged phosphonium is observed. Catalytic conditions have been developed as well as the activation of less reactive bonds (C–Br and C–Cl) were developed. The reopening of the ring by oxidative addition to gold is also observed.The fourth chapter deals with the second access strategy for the copper(III) complex, intermolecular oxidative addition from a bent copper(I) complex, carrying an LX bidente ligand. The choice of β-diketiminate ligands was performed in accordance with the predictive theoretical calculations. The non-innocence of these ligands led to their functionalization. Anilido-imines have constituted an interesting alternative allowing the formation of copper(I) π-complexes with alkenes and 1,3-dienes.The fifth chapter is about the synthesis of gold(I) anilido-imines complexes and the study of their reactivity toward oxidative addition. Gold(III) complexes are more stable than copper(III) complexes, the formation of new gold(III) complexes can help better understand the stabilization of copper(III) complexes
Paquit, Bénédicte. "Nouvelles méthodologies pour le clivage oxydant de doubles liaisons d'acides gras." Thesis, Lyon 1, 2009. http://www.theses.fr/2009LYO10291/document.
Повний текст джерелаIndustrial production of two high added value compounds called pelargonic acid and azelaic acid is made possible by the ozonolysis reaction of oleic acid. However, this method has numerous disadvantages in term of ecological impact. In this dissertation, we present an alternative to the current industrial process in order to lower direct or indirect negative environmental impacts when synthetizing azelaic and pelargonic acids. At first we demonstrate that a two-step oxidative cleavage may be preferable to a one-step cleavage. Then we present in details a novel synthesis method which starts with the dihydroxylation of the fatty acids double bond using a well known method, followed by the oxidative cleavage in presence of sodium hypochlorite. One notes that this original fabrication process developed in our laboratory does not require to use transition metals nor organic solvents. As a complement to this work, we have subsequently studied the sodium hypochlorite to determine its role and operating mode in the vicinal diols cleavage reaction
Ranko, Romanić. "HEMOMETRIJSKI PRISTUP OPTIMIZACIJI TEHNOLOŠKIH PARAMETARA PROIZVODNJE HLADNO PRESOVANOG ULJA SEMENA VISOKOOLEINSKOG SUNCOKRETA." Phd thesis, Univerzitet u Novom Sadu, Tehnološki fakultet Novi Sad, 2015. http://www.cris.uns.ac.rs/record.jsf?recordId=95781&source=NDLTD&language=en.
Повний текст джерелаIn this dissertation the optimal conditions for the dehulling process of high-oleic sunflower seeds, as raw material for oil production, were tested and determined. The conducted studies provided data for the optimal values of moisture content in the seed and the air pressure in the seed dehulling machine, what presented the base for determination of the dehulling model. Also, conducted studies examine the effect of variable technological parameters, such as content of hull (ranging from 0 to 20%) and the impurities content (ranging from 0 to 10%) on the composition and quality of oil and cake, oil yield, oxidative stability, sensory quality and colour of cold pressed high-oleic sunflower oil.The obtained results were analyzed by modern classification (cluster analysis and principal component analysis) and regression chemometrics methods, and chemometric models whose implementation could contribute to the production of cold pressed oil of high quality and high oxidative stability were set. It was found that the defined mathematical models are statistically valid and that they could be used to optimize the technological parameters of production of cold pressed high-oleic sunflower oil. The validity of the set models, that is the quality of obtained correlations, were estimated based on the parameters of cross-validation.The maximum effectiveness of high-oleic sunflower seeds dehulling can be achieved under optimal conditions, i.e. when the moisture content in seed is 6,0% and when the air pressure in seed dehulling machine is 800 kPa. Regarding composition and quality of the oil and cake, oil yield, oxidative stability, sensory quality and color, cold pressed high-oleic sunflower oil could be produced from seed containing 10-20% hull and 0-5% impurities.
Godard, Anaïs. "Nouveaux procédés verts d'oxydation de l'acide oléique." Thesis, Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0155/document.
Повний текст джерелаIn a context of scarce oil resources and environmental pressures, the chemical industry needs to innovate by developing new production chains aiming the design of bioproducts from biobased raw materials. Unsaturated fatty acids derived from vegetable oils, thus represents renewable resources with a great potential, allowing to diversify petroleum based supplies. Our interest is focused on the oxidative cleavage reaction of unsaturated fatty acids to yield mono-acids and di-acids with shorter and odd hydrocarbon chains, which are not available at a natural state. Such hydrocarbon chains are attractive for industry because they meet specific properties. But, they are currently only produced from fossil resources. Therefore, the objective was to develop an efficient method for oxidative cleavage, less expensive and less polluting than ozonolysis, the only operational industrial process. The selected oxidizing conditions employs hydrogen peroxide as oxidant, together with a phase transfer catalyst, without using an organic solvent. Several phase transfer catalysts Q3{PO4[WO(O2)2]4} were prepared from tungstophosphoric acid, hydrogen peroxide and a quaternary ammonium salt (Q+,Cl-), in order to compare their effectiveness in transferring oxygen to the substrate in the organic phase. An optimization of reaction parameters was carried out with the most performing catalyst. In addition, two protocols have been developed for the in-situ preparation of the catalyst and its recovery after reaction. The method was extended to fatty acids derivatives, in order to obtain other short chain acids, having a wide range of applications. The environmental benefits associated with this new method were evaluated by calculating green indicators. To consider an easier recycling of the catalyst, the oxodiperoxotungstate anion {PO4[WO(O2)2]4}3-, the active species of the catalyst was supported on anion-exchange resins. Two types of macroporous resins were tested: commercial resins (Amberlite IRA 900 and Lewatit K7367) and modified resins (type Merrifield). We showed that the modified resins, lead to the oxidative cleavage of oleic acid with higher yields than commercial ones, despite the presence of solvent. However, the immobilisation of the oxodiperoxtungstate anion on commercial resins allows the one-step synthesis of acetals, compounds of great interest for the synthesis of derivatives with a high added value. Using acetone as both reagent and solvent, we obtained good yields in ketal. Furthermore, the "one-pot" acetalization reaction of oleic acid was extended to other solvents (alcohols) as an opportunity to synthesize a wide range of acetals. The developed process is particularly interesting as it leads to the direct synthesis of ketal or acetals from an unsaturated fatty acid, avoiding the intermediate reaction steps