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1
Waller, A. G. "Ipso-nitration studies." Thesis, University of Canterbury. Chemistry, 1989. http://hdl.handle.net/10092/8002.
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Reaction of 2,4,6-trialkyl phenols with nitrogen dioxide in organic solvents is known to yield trinitro and dinitro hydroxy cyclohexenones as major products of reaction. These compounds have been postulated as forming via the transient intermediacy of 6-nitrocyclohexa-2,4-dienones. In the first part of the thesis the reactions of the C6-benzyl analogues of 4-t-butyl-2,6- dimethylphenol (206) and 2-t-butyl-4,6-dimethylphenol (216), compounds (229) and (230) respectively, with nitrogen dioxide are shown to give products analogous to those observed in the reactions of the parent phenols. Reaction of 6-benzyl-4-t-butyl-2,6-dimethylcyclohexa-2,4-dienone (229) with nitrogen dioxide in benzene solution is shown to give all four stereoisomeric 2,5-dinitrocyclohex-3-enones (240)-(243), and three of the four possible stereoisomeric 2-hydrox:y-5-nitrocyclohex-3-enones (244)(246). In contrast, reaction of 6-benzyl-2-t-butyl-4,6-dimethylcyclohexa- 2,4-dienone (230) with nitrogen dioxide in dichloromethane solution is shown to yield cyclohex-2-enones as the major products of reaction - namely, the four stereoisomeric 4,5-dinitrocyclohex-2-enones (231)-(234). The cyclohex-3-enones (235)-(238) are isolated as minor products of reaction.
In the second part of the thesis, the reactions of p-cymene (401) with nitrogen dioxide in acetic anhydride and dichloromethane solutions are explored. In dichloromethane solution, all the products of reaction, with the exception of 2-nitro-p-cymene (403) and p-nitrotoluene (405), can be accounted for in terms of a mechanism involving initial hydrogen atom abstraction from the iso-propyl group of the p-cymene molecule. In contrast, the reaction of p-cymene in acetic anhydride solution is shown to yield a multitude of products, including 2-nitro-p-cymene (403) and p-nitrotoluene (405), the two substituted aromatic compounds (414) and (415), and the eleven substituted cyclohexenes (410)-(413), (416)-(421) and (434). The mode of formation of these cyclohexenes in particular, is discussed in terms of an overall mechanistic scheme for the reaction of p-cymene in acetic anhydride solution.
Throughout the thesis, extensive use is made of single crystal X-ray structure analysis, and high field Fourier transform n.m.r. techniques, in determining molecular structure. The structures of fifteen compounds have been determined by single crystal X-ray structure analyses.
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Readman, J. M. "Ipso-nitration studies." Thesis, University of Canterbury. Chemistry, 1985. http://hdl.handle.net/10092/8784.
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Nitration of 2,6-dimethyl-4-nitrophenol (40a) with fuming nitric acid gives the pair of C2-epimeric cyclohex-3-enones, (41) and (42), the dihydroxy cyclohex-3-enone and the 2,6-dimethyl-3,4-dinitrophenol (43). Reaction of the nitro phenol (40a) with nitrogen dioxide also gives compounds (41), (42), (43) and (44). The nitration of 2,6-dimethyl-4-bromophenol (40c) with fuming nitric acid (addition of the phenol to the acid) yields both possible C2-epimeric cyclohex-3-enones, (53) and (54), the trinitro cyclohex-3-enone (55) which decomposes to give the dinitro phenol (43), nitro phenol (58) and the 1,4-benzoquinone derivative (59). Nitration of the bromo phenol (40c) in fuming nitric acid (addition of the acid to the phenol) and reaction of the bromo phenol (40c) with nitrogen dioxide both lead to extensive nitrodebromination. The possible reaction pathways for phenols (40a) and (40c) are discussed.
Nitration of 1,2,3,5-tetramethylbenzene (66a) with fuming nitric acid gives the tetramethylnitrobenzene (85), products of side-chain modification (86)-(90), the rearranged 6,6-dimethylcyclohexenones (91), (92), (93) and (94), and 2,3,4,6-tetramethyl ketone derivatives (73)-(76), (95) and (96). Reaction of 2,3,4,6-tetramethylphenol (71) with nitrogen dioxide gives the hydroxy dinitro ketone (72) in addition to the trinitrocyclohexenones (74)-(77) and (82). The possible modes of formation of these compounds are discussed.
Nitration of 1,2,3-trimethyl-4,6-dinitrobenzene (103) with fuming nitric acid gives dimethylpropanedioic acid (108) (72%), hydroxy dienone (110) (8%) and the substituted benzoic acid (109) (9%). Corresponding nitration of 1,2,4,5-tetramethyl-
3,6-dinitrobenzene (117) gives the nitro dicarboxylic acid (119) (33%), dimethylpropanedioic acid (108) (11%) and the substituted benzoic acid (118) (49%). Compounds (108) and (119) are products of reaction pathways involving ipsosubstitution, followed by methyl migration.
Nitration of 2,4-dimethyl-6-nitrophenol (128) with fuming nitric acid gives two 1,4-benzoquinone derivatives (129) and (130), in addition to the two C4-epimeric cyclohex-2-enones (131) and (132), and a single cyclohex-3-enone (133). In addition, reaction of 2,4-dimethyl-6-nitrophenol (128) with nitrogen dioxide also gives (129), (130), (131), (132) and (133). Comment is made on the reaction mechanism and on the probable mode of conversion of the cyclohex-3-enone (133) to give the C4-epimeric cyclohex-2-enones (131) and (132).
The structures of nine compounds (42), (44), (54), (74), (82), (92), (93), (94) and (96), have been determined unambiguously by single crystal X-ray structure analyses.
3
Thompson, Claire. "Aromatic nucleophilic nitration." Thesis, University of Exeter, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390199.
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Gibbons, Linda Maria. "Nitration in inert fluids." Thesis, Durham University, 2000. http://etheses.dur.ac.uk/4534/.
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Nitration in Inert Fluids Traditional methods of nitration have several disadvantages including the environmental problem of disposal of the spent acid. A main aim of this work was to investigate alternative methods for nitration while minimising the amount of acid required. Perfluorocompounds have been used as bulking agents to replace partially the acid solvent. They are chemically inert and may be reused without the need for purification. Mechanistic and synthetic studies of nitration reactions have been made. Toluene was successfully nitrated to trinitrotoluene using less sulfuric acid than in traditional methods. Benzene, styrene and trans-stilbene have been nitrated using nitric acid or dinitrogen pentoxide in perfluorocompounds. Kinetic results have been obtained for the homogeneous nitrations by N(_2)O(_5) in perfluorodecalin of substrates including 4-chloroanisole, 4-bromophenetole, 4- bromophenol and various chlorophenols. The rate constants have been determined and some mechanistic conclusions have been made. The nitration of various amines using dinitrogen pentoxide or nitric acid in perfluorocarbons has been studied. Nitrated derivatives of morpholine, pyrrolidine, piperidine, oxazolidinone and pyrimidine were successfully obtained using N-(^t)butoxycarbonyl, acetyl or silyl amines.
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Noble, Darren Robert. "Regiospecific aromatic nitration via nitrosation." Thesis, University of Exeter, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263236.
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Van, Niekerk Rudolf Jacob Francois. "Evaluation of Lewis acid catalysed and other nitration strategies for the selective nitration of cresols." Thesis, Port Elizabeth Technikon, 2001. http://hdl.handle.net/10948/60.
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The nitration of m- and p-cresol was investigated under mild reaction conditions in a number of solvents; the effects of certain nitration catalysts were also evaluated. These different reaction parameters were evaluated in terms of their effect on a number of important reaction responses. Other important factors that were investigated were the manipulation of the isomer ratios by changing reaction parameters, as well as important process chemistry information, such as product distribution, isolation and purification, identification of side products formed, and evaluation of the heat of reaction. Use was made of an experimental design system to evaluate the effect of reaction parameters on the chosen design responses. It was found that the ratio of para to ortho nitrocresol products could be influenced slightly by using low concentrations of nitric acid and low reaction temperatures. A different mechanism for the formation of 2-methyl-1,4-benzoquinone (from mcresol nitration) was proposed (compared with that previously reported), which could explain a “one mole nitric acid” pathway and the fact that only the pbenzoquinone isomer was observed. Reaction side products were identified and found to consist of dimers of cresol and nitrocresol, which were probably the result of oxidation of the cresol, subsequent formation of a quinomethide intermediate and reaction with either the product or the substrate. The heat of nitration was determined for various reaction systems and found to be governed by two factors, namely the actual nitration process and also an oxidation process, which is responsible for the formation of side products.
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Ruhweza, Moses. "Computer simulation of Dinitrotoluene Nitration Process." Thesis, Karlstads universitet, Avdelningen för kemiteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-66259.
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p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.5px Garamond} This paper presents an approach for modelling a commercial dinitrotoluene (DNT) production process using the CHEMCAD simulation software. A validation of the model was performed based on results of an experimental study carried out at Chematur Engineering AB, Sweden. Important parameters such as fluid properties, temperature profile and other operating conditions for CHEMCAD steady state model were selected so as to obtain the crude DNT yield as well as the acid –and organic phase compositions within the same range as the reference values from the experimental study. The results showed that the assumption of the steady state model was correct, and that acid –and organic phase compositions were in good agreement, although with a slightly lower sulphuric acid concentration than that observed in the experimental study. Also, a detailed study was carried out to analyse the effects of physicochemical conditions on the desired product yield. Both the results from the experimental study and the simulated model agree that the effects of mixed acids or heats of mixing acids contribute significantly to the energy balance. For the appropriateness of the thermodynamics, a NRTL model was chosen and the reactor system was optimized by an equilibrium based approach, producing MNT in 99.8% yield and crude DNT in 99.9% yield. An 80.1/19.9 DNT isomer ratio of the main isomers was achieved and a reduction of by-products in the crude DNT shows a good agreement between the model and the experimental study.<br>p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.5px Garamond} I denna rapport presenteras en metod för att modellera en kommersiell nitreringsprocess för tillverkning av dinitrotoluen (DNT) med simuleringsprogrammet CHEMCAD. En validering av modellen gjordes baserat på resultat från en experimentell studie utförd hos Chimärer Engineering AB, Sverige. CHEMCAD-modellen utgår från ”steady-state” drift av anläggningen. Viktiga parametrar såsom fluidegenskaper, temperaturprofil och andra driftsbetingelser i CHEMCAD-modellen valdes för att erhålla ett utbyte av DNT samt sammansättningar av såväl syrafas som organisk fas i god överensstämmelse med referensvärdena från den experimentella studien. Resultaten visade att antagandena i modellen var korrekta och sammansättningarna för syrafasen och den organiska fasen överensstämde med data från den experimentella studien. Det genomfördes också en detaljerad studie för att analysera effekterna av fysikalisk-kemiska betingelser på det önskade produktutbytet. Både resultaten från den experimentella studien och data från anläggning i drift överensstämde med den simulerade modellen avseende utspädningsvärmens bidrag till energibalansen. För att erhålla en lämplig beskrivning av reaktionssystemets termodynamik valdes en NRTL-modell och reaktorsystemet optimerades, vilket gav 99,8 % utbyte av MNT och 99,9 % DNT utbyte. Ett förhållande på 80,1 / 19,9 mellan de två huvudisomererna av DNT uppnåddes och en minskning av biprodukter i DNT produktblandningen. Detta är två exempel på en bra överensstämmelse mellan modellen och experimentstudien.
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Belson, D. J. "Aromatic nitration using aqueous nitric acid." Thesis, Loughborough University, 1989. https://dspace.lboro.ac.uk/2134/11976.
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The rates of nitration of benzene, toluene, anisole, p-xylene and mesitylene in aqueous nitric acid have been determined for concentratians in the range 24-41 mol % HNO3 and at temperatures between 293 and 333K. Correlation of rate constants with values of acidity function confirms that the mechanism of nitration in aqueous nitric acid is similar to that in aqueous Sulphuric acid.
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Beake, Benjamin David. "Nitration and oxidation with nitrous acid." Thesis, University of Exeter, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240290.
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O'Sullivan, Brian. "Nitration via the nitrosation/oxidation pathway." Thesis, University of Exeter, 1994. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.549310.
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Akouz, Toufiq. "Nitration aromatique sur catalyseurs acides solides." Montpellier 2, 1991. http://www.theses.fr/1991MON20147.
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La nitration des composes aromatiques en phase gazeuse par le peroxyde d'azote est catalysee par les silicoaluminates amorphes (silice-alumine) ou crystallises (zeolithes). Les resultats cinetiques sont en accord avec un mecanisme par transfert monoelectronique conduisant a un radical cation aromatique intermediaire. L'etude comparative de divers catalyseurs montre que l'activite est liee au nombre et a la force des sites acides ainsi qu'a leur accessibilite. L'addition de vapeur d'eau ameliore la stabilite des catalyseurs ainsi que l'activite des zeolithes mais diminue l'activite de la silice alumine. La structure des zeolithes n'a pas d'effet sur la selectivite de position ortho, meta, para
12
Petit, Fabien. "Optimisation de la nitration et de la dépolymérisation de la cellulose." Thesis, Bordeaux 1, 2008. http://www.theses.fr/2008BOR13730.
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Langlet, Abraham. "Nitration of Oxo-pyramidines and Oxo-imidazoles." Doctoral thesis, KTH, Kemi, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-601.
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This thesis is mainly focused on the reactions of oxo-pyrimidines and oxo-imidazoles with nitric acid in sulfuric acid and properties of the gem-dinitro products formed in this process. Low temperature nitrations of 2-methylimidazoles produced – in addition to the known 2-methyl-5(4)-nitroimidazole – 2-(dinitromethylene)-5,5-dinitro-4-imidazolidinone and parabanic acid. This tetranitro compound was also obtained via nitration of 2-methyl-4,4-dihydro-(1H)-5- imidazolone. Thermal decomposition of 2-(dinitromethylene)-5,5-dinitro-4-imidazolidinone yielded 2-(dinitromethylene)-4,5-imidazolidinedione, which also was the product from the nitration of the new compound 2-methoxy-2-methyl-4,5-imidazolidienedione. Treatment of 2- (dinitromethylene)-5,5-dinitro-4-imidazolidinone with aqueous ammonia resulted in the previously unknown 1,1-diamino-2,2-dinitroethylene (Paper I). The nitration of some 2-substituted pyrimidine-4,6-diones in sulfuric acid, which afforded previously unknown 5,5-gem-dinitro-pyrimidine-4,6-diones in high yields, was studied. Alloxane was prepared in a one-step procedure by thermal decomposition of 5,5-dinitrobarbituric acid in hot acetic acid. The gem-dinitro products were found to be easily attacked by nucleophiles with concomitant formation of gem-dinitroacetyl derivatives, which in turn could be further hydrolysed to salts of dinitromethane and triureas (Papers II and III). Nitration of 4,6-dihydroxypyrimidine in sulfuric acid yielded nitroform as the sole product. This behaviour was tentatively explained by the formation of an intermediate, 5,5-dinitro-4,6- dihydroxypyrimidine, which underwent hydrolysis in the nitrating acid into gem-dinitroacetyl formamidine. This compound was further nitrated in the same reaction mixture into trinitroacetylformamidine, which finally underwent hydrolytic cleavage into nitroform. It was also demonstrated that gem-dinitroacetylureas could produce nitroform upon nitration. The structures of the proposed trinitroacetylureas were confirmed by the isolation of one of their derivatives (Paper IV).<br>QC 20100907
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Langlet, Abraham. "Nitration of oxo-pyrimidines and oxo-imidazoles /." Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-601.
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Sanderson, A. J. "Nitration with dinitrogen pentoxide in nitric acid." Thesis, University of Exeter, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.232979.
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Melhuish, M. W. "Nitration and chlorination of deactivated aromatic compounds." Thesis, University of Exeter, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379462.
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Ajarim, Mansour Dahish S. "Nitration of simple aromatics over zeolite catalysts." Thesis, Cardiff University, 2010. http://orca.cf.ac.uk/54963/.
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The aim of this study was to develop new nitration systems using zeolite catalysts for the nitration of a highly activated compound, phenol, and for highly deactivated aromatics. It was hoped that such systems would produce high yields of the nitro products and in high pora-selectivity. Chapter One Chapter one describes the important role of Green Chemistry in the chemical industry. For example, modern synthetic methods should ideally be safe, be atom efficient, generate minimal waste, not involve solvent, have minimal energy requirement, be based on renewable resources, and be environmentally benign. Advances have been made by the use of solid catalysts such as zeolites and employing green solvents such as water, supercritical carbon dioxide and ionic liquids. Chapter Two Chapter Two describes a literature survey for the use of zeolite catalysts in nitration reactions of various aromatic compounds. Zeolite catalysts offer approaches to para-nitro aromatics, with the advantage of easy separation of the catalyst from the reaction mixture by filtration. Zeolites can be recovered and reused several times to give almost the same yields and selectivities as those obtained when fresh zeolite is used, with the avoidance of toxic waste generated by traditional Lewis acids. Chapter Three Chapter Three describes the nitration of phenol over several types of zeolites using wo-propyl nitrate as the nitrating reagent. Zeolite Hp with a Si/Al ratio of 12.5 was the most active of the catalysts tried and also gave the highest proportion of para-nitrophenol, but the paralortho ratio was still only around 1:1. Mono nitrophenols are formed in high yields when reactions are carried out over two days in refluxing dichloroethane as a solvent. A somewhat higher yield of mononitration products and a slightly better paralortho ratio could be achieved with a larger quantity of HZSM-5 under otherwise similar conditions. The reactions also produced small quantities of z'so-propoxybenzene as the main by-product. Chapter Four Chapter Four describes the nitration of deactivated aromatics using a nitric acid/acid anhydride/zeolite system. Various types of zeolites were used including proton-exchanged and passivated Hp. For example, nitration of benzonitrile over Hp produces a quantitative yield of nitrobenzonitriles comprising only 3- and 4-nitrobenzonitriles, with no 2-nitrobenzonitrile produced in most cases under the conditions tried. Trifluoroacetic and chloroacetic anhydrides were found to be the most active of the anhydrides tried. Also, zeolite Hp with a Si/Al ratio of 12.5 was the most active of the catalysts tried and also gave high pora-selectivity. The highest yield of 4-nitrobenzonitrile (33%), with a paralmeta ratio of ca. 0.50, was obtained using passivated Hp. Furthermore, heating easily regenerates the zeolite, which can be reused up to six times to give results similar to those obtained with a fresh sample of the catalyst. The process was found to be general for the nitration of monosubstituted deactivated aromatic compounds and gave significantly increased proportions of para-substituted isomers compared with the results obtained from the traditional mixed acid method.
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FAVRESSE, FABIEN. "Nouvelle methode de nitration des heterocycles aromatiques." Nantes, 2000. http://www.theses.fr/2000NANT2089.
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La chimie des materiaux hautement energetiques (explosifs) fait intervenir le plus souvent des molecules nitrees avec une avancee vers des molecules polycycliques tendues susceptibles de realiser un bon compromis entre performance et securite. Dans ce contexte, notre approche a consiste a tenter des nitrations d'heterocycles aromatiques prealablement silyles ou stannyles dans des conditions aussi neutres que possible (utilisation de tetranitromethane ou de tetraoxyde de diazote). Les precurseurs trimethylstannyles nous ont permis d'atteindre le 2-nitrobenzobfurane, le 2-nitrobenzobthiophene, le 2-nitroindoles et la 2-nitropyridine avec dans les deux derniers cas un effet benefique d'une photoactivation. L'ensemble des resultats (succes et echecs) a pu etre rationalise en considerant les potentiels d'ionisation des heteroaryletains et ces considerations theoriques nous ont permis de predire que la 2,4,6-trinitro-1,3,5-triazine ne serait pas accessible par cette voie.
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Bertea, Leopold E. "Catalytic vapour-phase nitration of benzene over zeolites /." [S.l.], 1993. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10258.
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Voisin, Laurent. "Nitration du mononitrochlorotertiobutylbenzene en reacteurs diphasiques liquide-liquide." Paris, ENMP, 1988. http://www.theses.fr/1988ENMP0102.
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Voisin, Laurent. "Nitration du mononitrochlorotertiobutylbenzène en réacteurs diphasiques liquide-liquide." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb376191768.
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Dagade, S. P. "Nitration of aromatic compounds over solid acid catalysts." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2002. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2855.
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Kendall, Georgina. "Electrochemical modification of proteins for biosensors." Thesis, Coventry University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247679.
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Lennon, Christopher William. "Probing Isoforms of the Prion Protein through Tyrosine Nitration." The University of Montana, 2007. http://etd.lib.umt.edu/theses/available/etd-08282007-194643/.
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The prion protein (PrP) has multiple stable isoforms. When PrP misfolds, it aggregates and causes neurological disease and death in mammals. The structure of the non-pathogenic isoform has been determined while the structures of the disease related isoforms are unknown. The nitration labeling patterns of three PrP isoforms with peroxynitrite and tetranitromethane, as detected by mass spectrometry, are reported. Two conserved tyrosine residues (tyrosines 149 and 150) are not labeled by either reagent in the normal cellular form of the prion protein but these residues become reactive after the protein has been converted to one of two aggregated isoforms. Another difference observed is that two other conserved tyrosine residues, 225 and 226, are much less reactive in both aggregated isoforms, while all other tyrosine residues show virtually no isoform specific-labeling. Thus, two regions been identified in which Tyr residues undergo a change in solvent accessibility, which may be due to a conformational change in that region or to inter-subunit packing.
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Campbell, Colin James. "The electrochemical nitration of proteins and protein model systems." Thesis, Coventry University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361652.
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Mika, Anna. "Evaluation of Nitration/Anammox process by bacterial activity tests." Thesis, KTH, Mark- och vattenteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-173853.
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Partial Nitritation/Anammox process (deammonification process), by which occurs oxidation of ammonium to nitrogen gas by autotrophic bacteria in anaerobic conditions, considered to be cost-effective and environmentally friendly method of nitrogen removal. Present research work focuses on achieving a high nitrogen removal degree, thanks to Anammox bacteria, while providing the best performance of the ongoing process. Integrated fixed-film activated sludge (IFAS) reactor was supplied with the main stream of the wastewater after UASB reactor, characterized by low concentration of nitrogen and organic matter. The bacteria ability to accommodate, were tested in the biofilm and in the activated sludge, depending on the different stages in which the process were being conducted. Batch test, such as Specific Anammox Activity (SAA), Nitrate Uptake Rate (NUR) and Oxygen Uptake Rate (OUR), were used for the evaluation of activity of various groups of bacteria. On the basis of laboratory analysis verified the values obtained from the batch tests. It was determined that a high degree of nitrogen removal (92% of NH4-N) was achieved thanks to the dominant activity of the Anammox bacteria, with low participation of other groups of bacteria. It was also proved, that Anammox bacteria activity were overwhelming in the biofilm. Dominant role of Ammonium Oxidizing Bacteria (AOB) was associated with high activity of Anammox bacteria, which together satisfyingly out-competed Nitrite Oxidizing Bacteria (NOB) and heterotrophic bacteria. It has been shown that Anammox bacteria quickly adapt to the new conditions and they are able to assume a dominant role, even in the case of inoculation of the reactor with the sludge from SBR. This allows conclude, that in the case of operational problems, the reactor can be supplied from another source, in order not to inhibit the process.
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Al-Obaidi, U. "Nitrous acid catalysed nitration of phenols in sulphuric acid." Thesis, University of Exeter, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373818.
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Torres, Rasgado Enrique. "Nitration de la Tyrosine dans l’albumine et les lipoprotéines." Aix-Marseille 3, 2007. http://www.theses.fr/2007AIX30046.
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Nous avons étudié par CG-SM l’effet de l’albumine (Alb) sur la nitration douce de la tyrosine du complexe LDL-Alb (LAC), naturellement présent dans le plasma, par un générateur de peroxynitrite (ONOO-). Dans nos conditions, le taux de nitration de Tyr (3-NO2-Tyr/Tyr) de l’albumine seule est de 4,4 x 10-3 mol/mol en présence de HCO3-. L’albumine non nitrée ajoutée diminue le taux de nitration de LAC de 2,5 x 10-3 à 0,6 x 10-3 mol/mol. Nous avons ensuite posé la question de la réversibilité de la nitration. Nous avons montré l’existence d’une activité de dénitration portée par LAC et HDL vis à vis de l’albumine nitrée. La réaction produit 1 résidu Tyr pour 1 anion NO3–. L’activité est portée par une structure protéique spécifique. Elle est inhibée par le γ-tocophérol des LDL et HDL, par l’acide ellagique (AE), présent dans des baies et certaines boissons, et son métabolite méthylé, le 3,3’OMAE. Ces résultats posent les bases d’une conception nouvelle du rôle de la nitration<br>We studied the albumin (Alb) effect on the mild nitration of the LDL-Alb complex (LAC), naturally present in plasma, by a generator of ONOO- in the presence of HCO3- by means of a GC-MS procedure. In our hand the Tyr-nitration rate (3-NO2-Tyr/Tyr) was 4,4 x 10-3 mol/mol in albumin alone. Added non-nitrated albumin decreased the Tyr-nitration rate of LAC from 2,5 x 10-3 to 0,6 x 10-3 mol/mol. We then addressed the question of the reversibility of the Tyr nitration. We found out that a nitratase activity against nitrated albumin occurs in LAC and HDL. Reaction products were 1 Tyr residue for 1 NO3- anion. The nitratase activity is borne by a specific protein structure. It was inhibited by LDL- and HDL γ-tocopherol, by ellagic acid (EA), present in berries and some drinks, and by its methylated metabolite, 3,3' OMAE. These results put forward a new concept on the role of nitration
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Short, Robert D. "An investigation of the surface and bulk nitration of cellulose." Thesis, Durham University, 1986. http://etheses.dur.ac.uk/7098/.
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Modern analytical techniques have been employed to investigate the nitration reaction of cellulose. The nitronium ion, NO(_2)(^+), is shown to be the important nitrating species of cellulose in the nitrating media employed. In mixes of high nitronium ion concentration, nitration at the cellulose surface is observed, by ESCA, to be extremely rapid, while in mixes of low nitronium ion concentration it is observed to be comparatively slow. It is shown that the degree of substitution (DOS) achieved at the fibre surface is equilibrium controlled. However, it is also shown that cellulose morphology plays an important role in determining the final bulk DOS achieved by nitration. The surface and bulk nitration of cellulose in dichloromethane/nitric acid mixes has been investigated by a variety of techniques. (^13)C solution state nmr has been employed to monitor the partial DOS established at the individual sites of the anhydroglucose residues. The substitution distribution patterns observed for materials in the DOS range 1.8 → 2.4 are very dependent on the nitrating media employed. Further, the differences in the substitution distribution pattern are reflected in the d(l0l) mean interchain spacing. A possible explanation for these differences is forwarded. The plasma etching of cellulose nitrate has been investigated as a function of DOS. The influence of sulphate ester residues on etch rate is also considered.
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Sasaki, Mikio. "Synthetic Studies on Nitro Compounds and Aziridines." 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/49752.
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学位授与大学：京都大学 ; 取得学位: 博士(工学) ; 学位授与年月日: 2007-11-26 ; 学位の種類: 新制・論文博士 ; 学位記番号: 論工博第3971号 ; 請求記号: 新制/工/1422 ; 整理番号: 25647<br>Kyoto University (京都大学)<br>0048<br>新制・論文博士<br>博士(工学)<br>乙第12135号<br>論工博第3971号<br>新制||工||1422(附属図書館)<br>25647<br>UT51-2007-S505<br>(主査)教授 吉田 潤一, 教授 檜山 爲次郎, 教授 杉野目 道紀<br>学位規則第4条第2項該当
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Husaini, Roslina. "Towards the Investigation of the Effects of Nitration on the Activity of the Human p53 Tumour Suppressor Protein. Nitration of the p53 Tumour Suppressor Protein." Thesis, University of Bradford, 2014. http://hdl.handle.net/10454/14788.
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Upon responding to cellular stress, p53 protein becomes stabilised and acts as a transcription factor mainly resulting from phosphorylation and acetylation of the protein. Nitration of p53 protein is poorly characterised by comparison with phosphorylation and acetylation. The main aim of this work was to study the effects of nitration on p53 functional activities and on p53-MDM2 protein-protein interactions. Preliminary work was to characterise the nitration of p53 protein over-expressed in E. coli BL21(DE3) which was then purified by a series of column chromatography. GST-MDM2 protein along with control GST protein were also overexpressed in BL21 which were subsequently purified by a single step batch purification before subjected to nitration. Peroxynitrite, a nitrating agent used in this study, was generated in vitro. Preliminary nitration work was carried out using BSA as a model protein as it is easily nitrated owing to its high number of tyrosine residues (19 residues). The present results showed that p53 and GST-MDM2 proteins were hardly nitrated as no strong nitro-tyrosine signals were obtained. This might be due to these proteins, being overexpressed in E. coli, were not properly folded resulting in hidden/cryptic tyrosine residues of which making nitration difficult to achieve. Peroxynitrite was shown to have a degrading property, reducing protein levels of peroxynitrite-treated p53, GST-MDM2 and GST proteins. Immunoprecipitation studies of cancer cell lysates with different p53 status treated with peroxynitrite showed very weak signals of nitro-p53 protein in mutant p53 cells whereby no nitro-p53 protein signal in wild-type p53 MCF7 cells. In addition, NO donor GSNO-treated MCF7 cells showed weak nitro-p53 protein signals.<br>Ministry of Science, Technology and Innovation (MOSTI) of Malaysia
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Hervé, Grégoire. "Progrès récents dans la chimie des molécules énergétiques : accès à de nouveaux hétérocycles azotés aromatiques très performants." Aix-Marseille 3, 2009. http://www.theses.fr/2009AIX30031.
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L'objectif de cette thèse consiste à mettre au point des molécules explosibles thermiquement stables, hautement énergétiques, à faible sensibilité selon des procédés de synthèse économiques et industriels. Certains composés énergétiques aromatiques bien ciblés, synthétisés dans le cadre de ces travaux, présentent des caractéristiques jamais égalées en terme de performance et de sensibilité (sûreté de fonctionnement). Ces avancées techniques offrent de nouvelles perspectives dans l’exploitation, la fabrication et l’utilisation de nouveaux matériaux énergétiques de défense performants à plus faible vulnérabilité. Ce travail fait également mention à un nouveau composé aromatique hautement nitré, lequel présente un niveau de stabilité sans équivalence en comparaison à tous les systèmes aromatiques analogues (nitroazoles, hexanitrobenzène, dinitrofurazane…)<br>The purpose of this thesis work was to design and to prepare new stable, highly-energetic and insensitive (or low-sensitive at least) explosives by the means of economical and industrial synthetic pathways. The synthesis of certain aromatic energetic compounds prepared in this framework affords significant enhancement in terms of energetic and physical properties ensuring ease of utilization and handling of such new materials in respect with high energetic performance. Several explosives exhibit unprecedented properties and offer a remarkable performance/sensitivity balance. A novel fully C-nitrated aromatic explosive is presented here and has, by far, the most important thermal and chemical stability in these series versus all the known nitrocarbons (i. E. Hexanitrobenzene) and nitroazoles
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Diop, Adji Dieynaba. "Synthèse d'un additif procétane biosourcé par nitration : Modélisation et étude cinétique par calorimétrie réactionnelle." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMR101.
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L’utilisation d’additifs procétanes est indispensable pour respecter la réglementation en matière de lutte contre la pollution liée au moteur diesel. Ces molécules actives sont destinées à augmenter les performances du carburant. Aujourd’hui, l’additif procétane le plus utilisé est le 2-ethylhexyl nitrate (EHN), obtenu par nitration de l’iso-octanol (dérivé du pétrole). L’objectif de ce travail est de synthétiser un substitut biosourcé à l’EHN en réalisant la nitration d’un biodiesel. Cette étude sera complétée par une modélisation et une estimation des paramètres cinétiques et énergétiques associés à la réaction de synthèse. Ces paramètres sont déterminés grâce à une méthode inverse basée sur la reconstruction des profils de puissance mesurés par le RC1 en mode semi-batch. Afin de proposer un modèle fiable capable de reproduire de façon fine le comportement du milieu réactionnel, l’approche adoptée dans ce travail consiste à d’abord caractériser le milieu réactionnel. La caractérisation comporte une étude calorimétrique et une étude chimique qui permettent d’évaluer la stabilité thermique du milieu réactionnel, d’identifier les différentes espèces présentes dans le produit nitré et de déterminer leur sélectivité. Suite à la caractérisation, il a été possible de proposer un modèle chimique pour estimer les paramètres cinétiques de la réaction. La réaction de synthèse a été réalisée avec deux agents de nitration (le mélange sulfonitrique et le nitrate d’acétyle) sur une plage de température allant de 10 °C à 50 °C. Les performances des bioadditifs obtenus ont été évaluées grâce à un moteur CFR. La forte exothermicité de la réaction, combinée à l’instabilité de certains produits, conduit à effectuer une étude de sécurité de la réaction afin d’évaluer sa criticité<br>To fight against pollution related to diesel engines, several techniques are used. Among them, the use of cetane improver is essential to comply with regulations. These active molecules are intended to increase the performance of fuel. Today, the most used cetane improver is the 2-ethylhexyl nitrate (EHN), obtained by nitration of iso-octanol (petroleum based raw material). The aim of this work is to synthesize a bio-based substitute to EHN by nitrating biodiesel. This study will be complemented by a modeling and an estimation of the kinetic and energetic parameters corresponding to the synthesis reaction.These parameters are obtained using an inverse method based on the reconstruction of power profiles measured by the reaction calorimeter (RC1). In order to propose a reliable model capable of reproducing the thermal behavior of the reaction medium, the approach adopted in this work was to begin by characterizing the reaction medium. The characterization involves a calorimetric and a chemical study that help to evaluate the thermal stability of the reaction medium, to identify the different species existing in the nitrated product and their selectivity. Following the characterization, it was possible topropose a chemical model ; which was used to estimate the reaction kinetic parameters. Two nitrating agents (mixing acid and acetyl nitrate) were used to synthesize the cetane improver between 10 °C and 50 °C. The bioadditive performance was evaluated using a CFR engine. The high exothermicity of the reaction, combined the instability of some of the products, lead us to perform a safety assessment of the reaction to evaluate its criticality
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Cheung, Clement. "Studies of the nitration of cellulose - application in new membrane materials." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46048.
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Liu, Shifang. "Nitration of simple aromatics and epoxidation of alkenes in ionic liquids." Thesis, Swansea University, 2003. https://cronfa.swan.ac.uk/Record/cronfa42847.
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Maffioli, E. M. "PROTEIN TYROSINE NITRATION UNDER PHYSIOLOGICAL CONDITIONS IN CELLULAR AND ANIMAL MODELS." Doctoral thesis, Università degli Studi di Milano, 2013. http://hdl.handle.net/2434/217446.
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The significance of NO2Tyr in vivo is highlighted by observations that nitrated proteins are markedly elevated in a broad range of human diseases and clinical disorders. The presence of nitrated tyrosine residues was detected in human fluids and pathological tissues such as atherosclerotic plaques of coronary vessels, amyotrophic lateral sclerosis, and Alzheimer’s lesions, among many others.
Although the accumulation of nitrated proteins correlates well with many disease states and is considered a marker of oxidative stress under pathological conditions, substantial evidence has accrued that protein tyrosine nitration is a post-translational modification playing a role in physiological processes, including signal transduction, neuronal differentiation, and embryonic development.
On this regard, the aim of the research presented in this PhD thesis is to better understand the significance of protein nitration under normal physiological conditions focusing on differentiation and developmental processes.
The PhD thesis is divided in four parts. The first introductory part is dedicated to presenting the biological functions of nitric oxide and its cellular effects in biological system. Particular attention has been devoted to protein tyrosine nitration and its pathological and physiological significance. Two different experimental models (cells and organism) have been used to investigate this issue: (a) a cellular model (PC12 cells) to discuss the effects of micro- and nanoscale topography on neuronal proliferation and differentiation and (b) an animal model (Ciona intestinalis) for studying the role of oxidative stress and NO-derived reactive nitrogen species (RNS) during Ciona development and metamorphosis-related events. In particular, as far as the first model is concerned, my studies were directed to the characterization of PC12 cells behavior on nanostructured TiO2 films in the presence and in the absence of the classical inducer of differentiation NGF. In the second part of the thesis I present the experimental procedures used. Proteomics techniques, including mono- and two-dimensional electrophoresis, electroblotting and immunostaining, and mass spectrometry (MALDI-TOF and LTQ-Orbitrap Velos) have been used to study both experimental models. In the third part the results obtained are reported. Our findings suggest that tyrosine nitration is a physiological event not necessary related to pathological processes and that this NO-mediated post-translational modification of proteins may be regarded as a direct way to NO-signaling transduction. Finally, in the last part I resume the main conclusions and present future perspectives.
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Hochstrasser, Patrick. "Procédé continu de nitration du benzène avec distillation azéotropique du mélange réactionnel /." [S.l.] : [s.n.], 1985. http://library.epfl.ch/theses/?nr=571.
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Sharp, Michael W. "Studies of the synthesis and nitration of dibenzotetra-azapentalenes and related systems." Thesis, Brunel University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294500.
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Barden, Joel M. "A study of the regioselectivity in the zeolite-assisted nitration of toluene /." Electronic version (PDF), 2003. http://dl.uncw.edu/etd/2003/bardenj/joelbarden.html.
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From, Malin, Johanna Ejerhed, Artin Fattah, Markus Lindén, and Alex Karlstens. "Heat Resistant Steel Alloys : Atlas Copco." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-256662.
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Atlas Copco is interested in investigating the friction in the top-hammer drilling tool threads thatcauses the steel to heat up, leading to a phase transformation and a softer steel in the threads. Theaim of this project is to find a steel alloy or surface finishing that will retain its hardness atelevated temperatures better than the presently used threads material. The solution is intended tobe used as a replacement material for the threads. The potential material is meant to combat thepremature breakdowns of the threads and thus minimizing the economical losses. To achieve ourproject goal, literature studies and an experimental parts were employed.Hardening methods are discussed thoroughly in the thesis, such as carbides/nitrides,precipitation, solid solution, grain size, and martensitic transformation. Alloying elements andtheir effects on steels properties were also discussed. C, Cr, Co, Mn, Mo, Ni, W, and V werefound to increase the steel's hardness at elevated temperature, high temperature strength andabrasion wear resistance.Nitration can be applied to most of the steels that Atlas Copco uses today, and will give a harder,and more wear resistant surface at elevated temperatures. A problem with nitration is that thenitrided layer is generally thinner than the martensitic hardening used today.Three tool steels samples (ASP 2030, ASP 2053 and ASP 2060) were acquired from Erasteel.These were used in the experimental part and compared to reference steels that Atlas Copcocurrently are using (R1-R6). The experiments were conducted in 400 and 600°C and the sampleswere tempered for 1, 10 and 100 hours before the hardness were measured with a Vickershardness test. The conclusion from the experiments was that ASP 2060 and ASP 2053 fromErasteel are the steels that have a much higher hardness at elevated temperature than the othersteels tested in the experiment. The results indicate that the tool steels will probably notexperience the same premature breakdown as the threads used today. R1 and ASP 2053 have thegreatest heat resistance.The suggested tool steels are all quite expensive, and to minimize the material needed only thethreads and not the rod can be in the new alloy. Lowering the cost could also be achieved byhardfacing where a layer of the new expensive alloy is welded onto a cheaper steel.
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Mori, Tadashi. "Mechanistic Aspects of the Ozone-mediated Nitration of Aromatic Compounds with Nitrogen Dioxide." 京都大学 (Kyoto University), 1997. http://hdl.handle.net/2433/202479.
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Guo, Xinxin. "Laboratory studies of the Henry's Law constants and nitration of phenol and nitrophenols." Thesis, University of East Anglia, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.518353.
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Seeley, Kent W. "Mass Spectrometry-based Methods for the Detection and Characterization of Protein-Tyrosine Nitration." Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4766.
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Protein tyrosine nitration (PTN) is a posttranslational modification resulting from oxidative/nitrosative stress that has been implicated in a wide variety of disease states. Characterization of PTN is challenging due to several factors including its low abundance in a given proteome, preferential site modification, multiple target site proximity within unique peptide sequences, and analytical method and instrument limitations. Current analytical techniques are insufficiently sensitive to identify endogenous nitration sites without incorporation of either nitrotyrosine or target protein enrichment. However, enrichment proficiency can also be inadequate. Chemical derivatization of the nitro- moiety can be incomplete or result in undesirable byproduct formation, while immunoaffinity proficiency is contingent upon antibody specificity. To overcome analytical method and enrichment deficiencies, we aimed to develop a comprehensive nitroproteome-specific workflow using molecular methods combined with mass spectrometry. Our approach was to systematically address all relevant factors contributing to PTN such as primary sequence, protein conformation, solvent accessibility, and nitrating agent concentration. Our ultimate goal was to increase mass spectrometric sensitivity for PTN identification. All putative nitroprotein/nitropeptide identifications were then subjected to rigorous validation by either manual spectrum analyses or peptide synthesis. We further developed MS methods for quantitation of nitropeptides from complex mixtures with minimal sample processing. Successful application of our nitroproteome-specific mass spectrometric workflow is expected to provide powerful tools for comprehensive PTN investigation that will elucidate its role in the onset and progression of a variety of disease states as well as facilitate discovery of therapeutic targets.
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Rodriguez, Medina Inmaculada Concepcion. "Studies on oxidative aromatic substitution." Thesis, University of Sussex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390923.
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Lugadet-Pe, Françoise. "Modification chimique de polymères polyinsaturés : étude de la nitration et de l'azidation de polybutadiennes hydroxytéléchéliques." Bordeaux 1, 1988. http://www.theses.fr/1988BOR10599.
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La nitration des polybutadienedihydroxy a ete effectuee par nitromercuration, l'azidation par iodoazidation deioduration. Les polymeres modifies sont caracterises au plan de leur structure et de leurs proprietes physiques
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Benamar, Ahmad. "Nitruration des couches minces d'oxyde de silicium par activation thermique et par simulation electronique." Lyon, INSA, 1989. http://www.theses.fr/1989ISAL0067.
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La nitration superficielle des couches très minces (130 À) de Si02 est réalisée par différentes techniques : à basse pression et à basse température (BT) ou à haute température (HT) et par recuit thermique rapide ( RTN) à la pression atmosphérique. Le procédé basse pression ( BT ou HT) permet de stimuler la réaction de nitruration à la surface de la silice, empêchant ainsi la diffusion, vers l'interface , des espèces nitrurantes. De même, la RTN évite la migration des espèces azotées et hydrogénées dans la masse de la silice et la redistribution des dopants. L'analyse physico-chimique (SIMS, AES, IRS, RS) a permis de mettre en évidence la nitruration de la surface de la silice, de contrôler les phénomènes de migration d'azote à l'interface Si-Si02 et a révélé les différentes liaisons chimiques (Si-N, Si-H, 0-H, N-H,. . ) susceptibles· d'être à l'origine d'un piégeage-dépiégeage des porteurs. L'analyse électrique des structures de test Al/Oxyde nitruré/ Si-p (mesures capacitives C-V et de conduction I-V) a permis de suivre l'évolution de la tension de bandes plates, de La rigidité diélectrique du matériau et des hauteurs de barrière interfaciales en fonction des conditions de nitruration. Différents types de pièges créés lors de la nitruration ont été détectés et caractérisés (concentration, section efficace de capture et barycentre). La qualité de l'interface (densité d'états Nit) dépend fortement des conditions et paramètres de la nitruration, de la qualité de l'oxyde initial: si 1e désordre interfacial est initialement élevé, il est généralement augmenté après nitruration, l'amplitude de cette variation dépend du mode de nitruration (continu ou séquentiel). En R1N la densité Nit diminue quand le temps de nitruration augmente. Globalement. La nitruration permet d'avoir des isolants de bonne qualité et peut être un procédé de passivation efficace. Si les conditions de nitruration sont optimisées les isolants (oxydes nitrurés) peuvent devenir meilleurs que les oxydes de silicium.
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Anantharaman, Muthuswamy. "NITRATION AND INACTIVATION OF MANGANESE SUPEROXIDE DISMUTASE PLAYS A CRITICAL ROLE IN METABOLIC SWITCH." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_diss/665.
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Alzheimer’s disease (AD) is a multifactorial, progressive, age-related neurodegenerative disease. Oxidative stress hypothesis is most prevalent and is gaining significant support. Inspite of the progress achieved on oxidative stress related damages in AD brain; the modification occurring on the various cellular antioxidant enzymes antioxidant has not been identified. Tyrosine nitration, a marker for peroxynitrite induced oxidative damage to protein is widespread in AD brain and Manganese superoxide dismutase (MnSOD), primary mitochondrial antioxidant enzyme is prone to peroxynitrite induced nitration and inactivation. Nitration of proteins involved in energy metabolism has been demonstrated in AD brain, which may explain the altered glucose metabolic status existing in AD brain. In the present study, we investigated the effect of tyrosine nitration of MnSOD on energy metabolism by the use of AD mouse model and cultured neuronal cells. The AD mouse model was generated from a double homozygous knock-in mouse, designated as APP/PS-1 mice, by incorporating the Swedish familial AD mutations in APP and P264L familial AD mutation in PS – 1. These animals develop age dependent increase in Aβ deposition beginning at 6 months along with an increase in insoluble Aβ1-40/Aβ1-42 levels. Genotype and age associated increase in nitration of MnSOD without any change in protein levels was also observed. MnSOD activity and mitochondrial respiration was decreased in APP/PS-1 mice. There was also concomitant increase in levels of lactate, an index of glycolytic activity in APP/PS-1 mice. To directly investigate the role of MnSOD inactivation in mitochondrial function and subsequent alteration in glycolytic activity, SH-SY5Y neuroblastoma cells line was used and treated with peroxynitrite. Enhanced nitration and reduction in the activity of MnSOD was observed upon peroxynitrite treatment. Peroxynitrite treatment also induced mitochondrial dysfunction, but MnSOD was inactivated at a concentration of peroxynitrite 10 times lower than that required to inhibit mitochondrial respiration. Mitochondrial dysfunction was alleviated by SOD mimetic and reproduced by MnSOD siRNA. The decline in mitochondrial function did not result in decreased ATP levels but was accompanied by an up-regulated glycolysis signified by high levels of lactate and lactate dehydrogenase activity but decreased activity of pyruvate dehydrogenase. These changes were prevented by SOD mimetic and were promoted by MnSOD siRNA. Specific reduction of MnSOD in MnSOD heterozygous knock-out mice resulted in decreased RCR and complex I activity with increased lactate levels. Taken together, these data demonstrate a critical role of MnSOD in influencing the mitochondrial function and thereby the switch in the energy metabolism switch that might occur under the pathological condition of MnSOD deficiency.
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Sultana, Razia. "Partial Nitration/anammox process in the moving bed biofilm reactor operated at low temperatures." Licentiate thesis, KTH, Mark- och vattenteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-145324.
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Jean-Gilles, Riffard P. "Acetyl-nitrate nitration of toluene by zeolite catalysts and methods of oxidation of graphite nanofibers." Click here for download, 2007. http://proquest.umi.com/pqdweb?did=1375524701&sid=1&Fmt=2&clientId=3260&RQT=309&VName=PQD.
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Philbin, Simon Patrick. "Studies of novel nitro-substituted nitrogen heterocyclic compounds." Thesis, Brunel University, 2001. http://bura.brunel.ac.uk/handle/2438/2165.
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The novel candidate high energy insensitive explosive; 2,5-diamino-3,6-dinitropyrazine (ANPZ-i) has been prepared in acceptable overall yield. ANPZ-i was synthesised by the nitration of 2,5-diethoxypyrazine using nitronium tetrafluoroborate (NO2+BF4-) in sulfolane and the subsequent amination of 2,5-diethoxy-3,6-dinitropyrazine, under autoclave conditions. Oxidation studies towards the dioxide derivative of ANPZ-i, 2,5-diamino-3,6-dinitropyrazine-1,4-dioxide (PZDO), were unsuccessful. The synthesis of existing high explosives; 2,6-diamino-3,5-dintropyrazine (ANPZ) and 2,6-diamino-3,5-dinitropyrazine-1-oxide (PZO) has been scaled up to produce approximately 25 g batches of material. A number of novel nitrations using NO2+BF4- have been carried out on a range of chloro-, methyl- and hydroxy-functionalised quinoxalines and quinazolines. A range of novel functionalisations have also been carried out on the platform molecule; 2,4-diamino-6,8-dinitroquinazoline giving rise to 2,4-diamino-6,8-dinitroquinazoline-1,3-dioxide (di-N-oxidation product), 2,4,7-triamino-6,8-dinitroquinazoline (monoamination product) and 2,4,6,8-tetra-aminoquinazoline (dihydrogenation product). Detonics molecular modelling was carried out on the following target molecules: 2,5-diamino-3,6-dinitropyrazine-1,4-dioxide (PZDO), 2,5,8-triamino-3,6,7-trinitroquinoxaline-1-oxide and 2,5,7-triamino-4,6,8-trinitroquinazoline-1-oxide. The detonation velocity of the new explosive molecule; 2,5-diamino-3,6-dinitropyrazine (ANPZ-i) was calculated and it was found to be a similar value to that obtained experimentally for the existing high explosive RDX. Calculation by molecular modelling of the steric energies of ANPZ, PZO, ANPZ-i and PZDO gave a quantitative assessment of the difficulty in oxidising ANPZ-i to give PZDO. Extensive analysis of carbon-13 NMR spectroscopy shift values was carried out for approximately twenty nitrogen heterocyclic compounds. Comparison of shift values indicated consistency in the interpretations. On-line literature searches have shown that the following compounds prepared in this project are new: 2,3,6-trichloro-5-nitroquinoxaline, 2,3-dimethoxy-6,7-dinitroquinoxaline, 2,3,6-trichloroquinoxaline-1-oxide, 2,4-diamino-6,8-dinitroquinazoline-1,3-dioxide, 2,4,7-triamino-6,8-dinitroquinazoline and 2,5-diamino-3,6-dinitropyrazine (ANPZ-i). Furthermore, new synthetic routes have been used in the preparation of the following compounds: 2,3-dichloro-5-nitroquinoxaline, 2,3,6,7-tetrachloro-5-nitroquinoxaline, 2-hydroxy-6-nitroquinoxaline, 2-hydroxy-3-methyl-6-nitroquinoxaline and 2,5-diethoxy-3,6-dinitropyrazine.