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Relevant bibliographies by topics / Oxygenation Reactions

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Academic literature on the topic 'Oxygenation Reactions'

Author: Grafiati

Published: 18 May 2024

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Journal articles on the topic "Oxygenation Reactions"

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Das, Ujjwal. "Platinum Group Metals Bonded Thiolato Sulfur Oxygenation: Photoactivity and Bioactivity." Asian Journal of Chemistry 34, no. 12 (2022): 3059–70. http://dx.doi.org/10.14233/ajchem.2022.24007.

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Platinum group metals mediated thiolato compounds are highly susceptible for S-centered reactivity owing to high nucleophilicity and which is enormously significant in the point of its bioactivity and photoactivity. A series of oxygenation reactions of thiolate sulfur attached with platinum metals occurred with molecular O2 in varying conditions. A variety of sulfenates and sulfinates are produced depending on nature of starting substrate thiolato and the oxygenations are facile under harshly oxygen environment. There are numerous mechanistic paths for the oxygenation of platinum metals bonded thiolate S-center unlike the oxygenation reaction of organic sulphides. It is assumed that S-oxygenation occurs via the intramolecular and intermolecular dioxygen addition pathways. A number of mysterious photo-induced sulphur oxygenation and self-sensitization reactions of metal-thiolato to analogous oxygenate are also mentioned. These compounds show enzymatic catalytic activity and remarkable bioactivity also interaction with the biomolecules like DNA, which opens a new area for the researchers for designing novel heavier metals-sulfur-oxygenates compounds as metallodrugs.

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Forchetta, Mattia, Francesca Valentini, Valeria Conte, Pierluca Galloni, and Federica Sabuzi. "Photocatalyzed Oxygenation Reactions with Organic Dyes: State of the Art and Future Perspectives." Catalysts 13, no. 2 (January 18, 2023): 220. http://dx.doi.org/10.3390/catal13020220.

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Oxygen atom incorporation into organic molecules is one of the most powerful strategies to increase their pharmacological activity and to obtain valuable intermediates in organic synthesis. Traditional oxidizing agents perform very well, but their environmental impact and their low selectivity constitute significant limitations. On the contrary, visible-light-promoted oxygenations represent a sustainable method for oxidizing organic compounds, since only molecular oxygen and a photocatalyst are required. Therefore, photocatalytic oxygenation reactions exhibit very high atom-economy and eco-compatibility. This mini-review collects and analyzes the most recent literature on organo-photocatalysis applications to promote the selective oxygenation of organic substrates. In particular, acridinium salts, Eosin Y, Rose Bengal, cyano-arenes, flavinium salts, and quinone-based dyes are widely used as photocatalysts in several organic transformations as the oxygenations of alkanes, alkenes, alkynes, aromatic compounds, amines, phosphines, silanes, and thioethers. In this context, organo-photocatalysts proved to be highly efficient in catalytic terms, showing similar or even superior performances with respect to their metal-based counterparts, while maintaining a low environmental impact. In addition, given the mild reaction conditions, visible-light-promoted photo-oxygenation processes often display remarkable selectivity, which is a striking feature for the late-stage functionalization of complex organic molecules.

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Bopp, Charlotte E., Hans-Peter E. Kohler, and Thomas B. Hofstetter. "Enzyme Kinetics of Organic Contaminant Oxygenations." CHIMIA International Journal for Chemistry 74, no. 3 (March 25, 2020): 108–14. http://dx.doi.org/10.2533/chimia.2020.108.

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Enzymatic oxygenations initiate biodegradation processes of many organic soil and water contaminants. Even though many biochemical aspects of oxygenation reactions are well-known, quantifying rates of oxidative contaminant removal as well as the extent of oxygenation remains a major challenge. Because enzymes use different strategies to activate O2, reactions leading to substrate oxygenation are not necessarily limiting the rate of contaminant removal. Moreover, oxygenases react along unproductive pathways without substrate metabolism leading to O2 uncoupling. Here, we identify the critical features of the catalytic cycles of selected oxygenases that determine rates and extents of biodegradation. We focus most specifically on Rieske dioxygenases, a subfamily of mononuclear non-heme ferrous iron oxygenases, because of their ability to hydroxylate unactivated aromatic structures and thus initiate the transformation of the most persistent organic contaminants. We illustrate that the rate-determining steps in their catalytic cycles range from O2 activation to substrate hydroxylation, depending on the extent of O–O cleavage that is required for generating the reactive Fe-oxygen species. The extent of O2 uncoupling, on the other hand, is highly substrate-specific and potentially modulated by adaptive responses to oxidative stress. Understanding the kinetic mechanisms of oxygenases will be key to assess organic contaminant biotransformation quantitatively.

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Yu, Mohan, and Yajun Liu. "A QM/MM Study on the Initiation Reaction of Firefly Bioluminescence—Enzymatic Oxidation of Luciferin." Molecules 26, no. 14 (July 12, 2021): 4222. http://dx.doi.org/10.3390/molecules26144222.

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Among all bioluminescent organisms, the firefly is the most famous, with a high luminescent efficiency of 41%, which is widely used in the fields of biotechnology, biomedicine and so on. The entire bioluminescence (BL) process involves a series of complicated in-vivo chemical reactions. The BL is initiated by the enzymatic oxidation of luciferin (LH2). However, the mechanism of the efficient spin-forbidden oxygenation is far from being totally understood. Via MD simulation and QM/MM calculations, this article describes the complete process of oxygenation in real protein. The oxygenation of luciferin is initiated by a single electron transfer from the trivalent anionic LH2 (L3−) to O2 to form 1[L•2−…O2•−]; the entire reaction is carried out along the ground-state potential energy surface to produce the dioxetanone (FDO−) via three transition states and two intermediates. The low energy barriers of the oxygenation reaction and biradical annihilation involved in the reaction explain this spin-forbidden reaction with high efficiency. This study is helpful for understanding the BL initiation of fireflies and the other oxygen-dependent bioluminescent organisms.

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Tang, Conghui, Xu Qiu, Zengrui Cheng, and Ning Jiao. "Molecular oxygen-mediated oxygenation reactions involving radicals." Chemical Society Reviews 50, no. 14 (2021): 8067–101. http://dx.doi.org/10.1039/d1cs00242b.

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Molecular oxygen as a green, inexpensive oxidant and oxygen source has displayed lots of advantages compared to other oxidants. This review introduces the recent advances of radical processes in molecular oxygen-mediated oxygenation reactions.

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Cheng, Xiaokai, Xingen Hu, and Zhan Lu. "Visible-Light-Promoted Aerobic Homogenous Oxygenation Reactions." Chinese Journal of Organic Chemistry 37, no. 2 (2017): 251. http://dx.doi.org/10.6023/cjoc201609022.

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Fukuzumi, Shunichi, Yong‐Min Lee, and Wonwoo Nam. "Photocatalytic Oxygenation Reactions Using Water and Dioxygen." ChemSusChem 12, no. 17 (July 25, 2019): 3931–40. http://dx.doi.org/10.1002/cssc.201901276.

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Perez, Daniel I., Maria Mifsud Grau, Isabel W. C. E. Arends, and Frank Hollmann. "Visible light-driven and chloroperoxidase-catalyzed oxygenation reactions." Chemical Communications, no. 44 (2009): 6848. http://dx.doi.org/10.1039/b915078a.

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Mihara, Satoru, and Hideki Tateba. "Photosensitized oxygenation reactions of phytol and its derivatives." Journal of Organic Chemistry 51, no. 7 (April 1986): 1142–44. http://dx.doi.org/10.1021/jo00357a043.

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MONTANARI, F., S. BANFI, G. POZZI, and S. QUICI. "ChemInform Abstract: Oxygenation Reactions under Two-Phase Conditions." ChemInform 26, no. 20 (August 18, 2010): no. http://dx.doi.org/10.1002/chin.199520261.

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Dissertations / Theses on the topic "Oxygenation Reactions"

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Agarwalla, Uday Sankar. "Oxygenation Reactions of Organic and Organometallic Compounds." Thesis, University of North Bengal, 2014. http://hdl.handle.net/123456789/1485.

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Mii, Haruka. "Development of Asymmetric Oxygenation Reactions Using New Chiral Secondary Amine Catalysts." 京都大学 (Kyoto University), 2010. http://hdl.handle.net/2433/120688.

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Deng, Yanpei. "Dioxygen binding properties of the cobalt(II) cyclidene complexes and their catalytic oxygenation reactions /." The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487758680158923.

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Meiners, Jenni [Verfasser], Sven [Akademischer Betreuer] Schneider, and Bernhard [Akademischer Betreuer] Rieger. "Iridium PNP pincer complexes: CH activation, oxygenation and oxidation reactions / Jenni Meiners. Gutachter: Bernhard Rieger ; Sven Schneider. Betreuer: Sven Schneider." München : Universitätsbibliothek der TU München, 2014. http://d-nb.info/1069127736/34.

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Heiden, Marina. "Psychophysiological reactions to experimental stress : relations to pain sensitivity, position sense and stress perception." Doctoral thesis, Umeå : Umeå University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-879.

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SUAREZ, BERTOA RICARDO. "Sustainable procedures in organic synthesis." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2009. http://hdl.handle.net/10281/7474.

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O-acyl-N-benzyllactamides are obtained in good yield by reaction of 4-benzyl-5-methyl-1,3-oxazolidine-2,4-diones with Grignards reagents and with lithium alkyls. Three alkanes and two ethers were oxidised with ozone in dichloromethane solution or in aqueous pH 3 suspension. Cyclodecane and cyclododecane were converted into the corresponding cycloalkanones. n-decane was converted into a mixture of isomeric n-decanones and carboxylic acids. An ester was formed from the ethers. Hence, one of the methylene groups of these substrates is generally converted into a carbonyl group. Some of these reactions have preparative value. The oxidation of naphthalene in dichloromethane or acetonitrile with excess ozone gives phthalic aldehyde, 2-formyl benzoic acid and phthalic anhydride. Small amounts of the (E)- and (Z)-isomer of 3-phenyl-(2-formyl)-propenal and are also observed in some cases. The reaction is faster in acetonitrile than in dichloromethane owing to the higher solubility of ozone in the former solvent. The reaction is faster on lowering the temperature because of the increase of the concentration of ozone in solution at lower temperature. With a 1:1 or a 1:2 naphthalene:ozone ratio high conversion and low selectivity for the anhydride is observed. The ozonation of cyclohexane in dichloromethane or acetonitrile gives cycloxexanone, cyclohexanol and acidic material. The influence of solvent, reactant concentration, amount of ozone, temperature, reaction time is studied. A reaction mechanism is proposed based on the results of a simulation of the reaction energetics. The ozonation of N-phenylmorpholine in dichloromethane or acetonitrile produced a lactame and a diformylderivative. These products derive from the attack of ozone at the heterocyclic ring. The reaction mechanism has been investigated by DFT calculations which show that the reaction occurs through the insertion of ozone at the carbon-hydrogen bond of a methylenic group of the morpholine ring. The regioselectivity is due to the to the significantly lower energy barrier calculated for the attack of ozone in α to nitrogen than in α to oxygen. Also, the energy barrier decreases with increasing the polarity of the solvent, accounting for the higher reaction rate observed for the reaction carried out in acetonitrile than in dichloromethane. The ozonation of trans- and cis-decalin in dichloromethane or acetonitrile gives the corresponding 9-hydroxydecalinns, 2- and 3-decalones and acidic material. The influence of solvent, reactant concentration, amount of ozone, temperature, reaction time is studied. A reaction mechanism is proposed based on the results of a simulation of the reaction energetics. The N,N bis(salicylidene)ethylenediaminocobalt(II) catalysed oxidative carbonylation of para-substituted aromatic primary amines at 100 °C in methanol gives carbamates in high yields. In presence of excess dimethylamine also N-aryl-N’,N’-dimethylureas are formed. In methylene chloride moderate yields in isocyanate are obtained. 1-methylbenzylamine gives the carbamate and the urea in high yield. i-propylamine gives only the urea. An α-aminoalcohol gives a 1,3-oxazolidin-2-one. Aliphatic secondary amines react faster and give carbamates in methanol and ureas in methylene chloride. The turnover frequency is also measured in two cases.

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Golen, Barbara. "Scanning tunneling microscopy of the oxygenation reaction on the silicon (100) surface." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.281968.

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Tosha, Takehiko. "Molecular mechanism of cytochrome p450cam-catalyzed oxygenation reaction regulated by the association with putidaredoxin." 京都大学 (Kyoto University), 2003. http://hdl.handle.net/2433/148546.

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Shakirullah, Mohammad. "Oxygenation et degradation du polymere, decoloration du sensibilisateur lors de la photooxygenation du polybutadiene-1,4 cis sensibilisee par les colorants." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13081.

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Sous l'influence conjuguee de la lumiere et de l'oxygene, une solution de polymere et de bleu de methylene subit plusieurs transformations. La photooxygenation conduit uniquement a des hydroperoxydes allergiques: interaction entre l'etat triplet du bleu de methylene et les groupes hydroperoxydes portes par les chaines macromoleculaires. Cinetique et mecanisme

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Guimard, Alexandre. "Etude des effets de la pratique de l'apnée pendant l'effort en laboratoire et sur le terrain : application en natation." Thesis, Orléans, 2017. http://www.theses.fr/2017ORLE2066.

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Existant en tant que pratique sportive, l’apnée est également de plus en plus utilisée dans d’autres activités sportives dont la natation, à l’entraînement et/ou en compétition. Toutefois, les réponses à l‘apnée dynamique ont été peu explorées lors d’efforts physiques intenses, en particulier en natation. L’objectif de ce travail de thèse est donc d’étudier sur le terrain en situation de nage (étude 1 et 2) et en laboratoire (étude 3) lors d’un exercice intermittent de pédalage, les réponses physiologiques, psychologiques et ergogéniques à l’apnée aiguë apparaissant lors d’efforts intenses. Le métabolisme a été notamment évalué à partir de la mesure de l’oxygénation tissulaire, de paramètres sanguins et de marqueurs hormonaux. Les principaux résultats de ces études montrent qu’en apnée la performance dépendrait de la capacité des sujets à maintenir leur fréquence cardiaque et que l’effort est globalement perçu comme plus dur. L’apnée n’induisait pas d’augmentation de la lactatémie, sans doute en lien avec l’absence de modification de l’extraction musculaire de l’oxygène. Au niveau cérébral, le maintien de l’oxygénation expliquerait la non modification du temps de réaction en apnée. Enfin toutes nos études ont révélé une désaturation artérielle significative en apnée, dès la première apnée de 10 secondes (étude 3) mais sans effet de la capacité d’apnée (étude 1) ou de l’intensité de nage (étude 2) suggérant que la durée compenserait l’intensité. Il serait donc intéressant d’étudier ultérieurement les effets respectifs du couple intensité/durée et les effets chroniques d’un entraînement comportant un exercice intermittent intense lors d’apnées dynamiques
Existing as a sport practice, apnea is also increasingly used in other sports activities including swimming, training and/or competition. However, responses to dynamic apnea have been little explored during intense physical exercise, especially in swimming. The objective of this thesis is to study, in the field in swimming situations (study 1 and 2) and in the laboratory (study 3) during an intermittent cycling exercise, the physiological, psychological and ergogenic responses to acute apnea appearing during intense exercises. Metabolism was especially assessed by measurement of tissue oxygenation, blood parameters and hormonal markers. The main results of these studies show that in apnea the performance would depend on the ability of the subjects to maintain their heart rate and that the exercise is globally perceived as harder. Apnea did not induce an increase in lactatemia, probably related to the lack of modification of the muscle extraction of oxygen. At the cerebral level, the maintenance of the oxygenation would explain that the reaction time is not altered with apnea. Finally, all our studies revealed a significant arterial desaturation in apnea at the first repetition of the 10-second apnea (study 3) but without the effect of apnea capacity (study 1) or swimming intensity (study 2) suggesting that the duration would compensate for the intensity. It would therefore be interesting to study later the respective effects of the intensity/duration pair and the chronic effects of training involving intense intermittent exercise during dynamic apneas

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Book chapters on the topic "Oxygenation Reactions"

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Montanari, Fernando, Stefano Banfi, Gianluca Pozzi, and Silvio Quici. "Oxygenation Reactions under Two-Phase Conditions." In Catalysis by Metal Complexes, 149–73. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-017-2247-6_5.

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Rein, H., and C. Jung. "Metabolic Reactions: Mechanisms of Substrate Oxygenation." In Cytochrome P450, 105–22. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-77763-9_7.

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Meunier, Bernard, and Sandro Campestrini. "Oxygenation Reactions Catalyzed by Supported Sulfonated Metalloporphyrins." In ACS Symposium Series, 58–66. Washington, DC: American Chemical Society, 1993. http://dx.doi.org/10.1021/bk-1993-0523.ch005.

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Perutz, M. F. "Mechanisms Regulating the Reactions of Human Hemoglobin with Oxygen and Carbon Monoxide." In Clinical Aspects of O2 Transport and Tissue Oxygenation, 3–25. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-83872-9_1.

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Gollnick, Klaus, Albert Schnatterer, Gerald Utschick, Uwe Paulmann, and Stephan Held. "Singlet Oxygen and Electron Transfer Induced Oxygenation Pathways in Reactions Photosensitized by Dicyanoanthracene and Hydroxy-Anthraquinones." In Light in Biology and Medicine, 67–76. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4613-0709-9_9.

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Viil, Juta. "Carboxylation and Oxygenation of ribulose-1,5-bisphosphate (Rubp): A Model on the Level of The Partial Reactions." In Photosynthesis: from Light to Biosphere, 4107–10. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-009-0173-5_966.

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Nishinaga, A., T. Yamada, H. Fujisawa, K. Ishizaki, H. Ihara, and T. Matsuura. "Catalysis of Cobalt Schiff Base Complexes for the Oxygenation of Olefins. Mechanisms for the Ketonization Reaction." In Oxygen Complexes and Oxygen Activation by Transition Metals, 316–18. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4613-0955-0_31.

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Hatanaka, Akikazu, Tadahiko Kajiwara, and Jiro Sekiya. "Enzymic Oxygenative-cleavage Reaction of Linolenic Acid in Leaves — Chloroplastic Lipoxygenase and Fatty Acid Hydroperoxide Lyase in Tea Leaves." In The Metabolism, Structure, and Function of Plant Lipids, 391–98. Boston, MA: Springer New York, 1987. http://dx.doi.org/10.1007/978-1-4684-5263-1_72.

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Taiz, Lincoln, Ian Max Møller, Angus Murphy, and Eduardo Zeiger. "Photosynthesis: The Carbon Reactions." In Plant Physiology and Development. Oxford University Press, 2023. http://dx.doi.org/10.1093/hesc/9780197614204.003.0013.

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This chapter describes the metabolic cycle and shows how this incorporates atmospheric CO₂ into organic compounds called the Calvin–Benson cycle. It considers how the unavoidable reaction of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) with molecular oxygen decreases the efficiency of photosynthetic CO₂ assimilation. It also explores how photorespiration releases CO₂ while recycling the by-products of the oxygenation reaction that would otherwise be unusable by the cell. The chapter examines C4 photosynthesis and crassulacean acid metabolism (CAM), which are CO₂-concentrating mechanisms that land plants have evolved for minimizing the oxygenation of Rubisco and the loss of energy and CO₂ during photorespiration. It looks at the formation of the two major products of the photosynthetic CO₂ fixation: starch and sucrose.

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Arnold, Ernst V., and D. Scott Bohle. "[5] Isolation and oxygenation reactions of nitrosylmyoglobins." In Methods in Enzymology, 41–55. Elsevier, 1996. http://dx.doi.org/10.1016/s0076-6879(96)69008-9.

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Conference papers on the topic "Oxygenation Reactions"

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Goriachaia, M. N., E. N. Altynbaeva, V. I. Ruzov, and Н. А. Slobodnyuk. "Morphofunctional assessment of platelet activity correction in hyperbaric blood oxygenation." In VIII Vserossijskaja konferencija s mezhdunarodnym uchastiem «Mediko-fiziologicheskie problemy jekologii cheloveka». Publishing center of Ulyanovsk State University, 2021. http://dx.doi.org/10.34014/mpphe.2021-84-86.

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100 patients with functional class II-III exertional angina were examined. The subjects underwent a 10-day course of hyperbaric oxygenation (HBO) in the 1.2 ATA mode for 40 minutes, against the background of standard therapy for coronary heart disease (IHD). Before and after HBO, the platelet link of hemostasis and the elastic properties of the platelet membrane were assessed. Assessment of the effect of the HBO course on the functional state of platelets, depending on their aggregation activity, showed that in patients with initially normal platelet aggregation, there is a tendency to a decrease in spontaneous aggregation, in contrast to patients with initial hypoaggregation, HBO promoted a significant increase in spontaneous aggregation. The use of a 10-day course of HBO was accompanied by a reaction of reducing the elasticity of the platelet biomembrane. Key words: aggregation; atomic force microscopy; platelet membrane; hyperbaric oxygenation.

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Kalvakala, Krishna C., and Suresh K. Aggarwal. "PAHs and Soot Emissions in Oxygenated Ethylene Diffusion Flames at Elevated Pressures." In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-77180.

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Operating combustion systems at elevated pressures has the advantage of improved thermal efficiency and system compactness. However, it also leads to increased soot emission. We report herein a computational study to characterize the effect of oxygenation on PAHs (Polycyclic Aromatic Hydrocarbons) and soot emissions in ethylene diffusion flames at pressures 1–8atm. Laminar oxygenated flames are established in a counterflow configuration by using N2 diluted fuel stream along with O2 enriched oxidizer stream such that the stoichiometric mixture fraction (ζst) is varied, but the adiabatic flame temperature is not materially changed. Simulations are performed using a validated fuel chemistry model and a detailed soot model. The primary objective of the study was to expand the fundamental understanding of PAH and soot formation in oxygenated flames at elevated pressures. At a given pressure, as the level of oxygenation (ζst) is increased, we observe a significant reduction in PAHs (benzene and pyrene) and consequently in soot formation. Further, at a fixed ζst, as pressure is increased, it leads to increased benzene and pyrene formation, and thus increased soot emission. The reaction path analysis indicates that this can be attributed to the fact that at higher pressures, the C2/C4 path becomes more significant for benzene formation compared to the propargyl recombination path.

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You, Xueji, Chaomeng Dai, and Charles Werth. "Kinetics Reaction Pathways of Hydroxyl Radical Production from Oxygenation of Reduced Iron Minerals and Their Reactivity with Trichloroethene: Simulating Real Environmental Scenarios." In Goldschmidt2023. France: European Association of Geochemistry, 2023. http://dx.doi.org/10.7185/gold2023.14166.

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Race, J. M., S. J. Dawson, L. Stanley, and S. Kariyawasam. "Predicting Corrosion Rates for Onshore Oil and Gas Pipelines." In 2006 International Pipeline Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/ipc2006-10261.

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One of the requirements of a comprehensive pipeline Integrity Management Plan (IMP) is the establishment of safe and cost effective re-assessment intervals for the chosen assessment method, either Direct Assessment (DA), In-Line Inspection (ILI) or hydrotesting. For pipelines where the major threat is external or internal corrosion, the determination of an appropriate re-inspection interval requires the estimation of realistic corrosion growth rates. The Office of Pipeline Safety (OPS 2005) estimate that the ability to accurately estimate corrosion rates may save pipeline companies more than $100M/year through reduced maintenance and accident avoidance costs. Unlike internal corrosion, which occurs in a closed system, the rate of the external corrosion reaction is influenced by a number of factors including the water content of the soil, the soluble salts present, the pH of the corrosion environment and the degree of oxygenation. Therefore the prediction of external rates is complex and there is currently no method for estimating corrosion rates using either empirical or mechanistic equations. This paper describes a scoring model that has been developed to estimate external corrosion growth rates for pipelines where rates cannot be estimated using more conventional methods i.e., from repeat in-line inspection data. The model considers the effect of the different variables that contribute to external corrosion and ranks them according to their effect on corrosion growth rate to produce a corrosion rate score. The resulting score is then linked to a corrosion rate database to obtain an estimated corrosion rate. The methodology has been validated by linking the calculated corrosion rate scores to known corrosion rate distributions that have been measured by comparison of the results from multiple in-line inspection runs. The paper goes on to illustrate how the estimated corrosion rates can be used for the establishment of reassessment intervals for DA, ILI and hydrotesting, comparing the benefits of this approach with current industry recommended practice and guidance.

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Ou, Juan, Ruomiao Yang, Yuchao Yan, Zhentao Liu, and Jinlong Liu. "The Effect of Methane Addition on the Low-Temperature Oxidation Preparation and the Thermal Ignition Preparation of Dimethyl Ether Under Representative Engine In-Cylinder Thermal Conditions." In 2023 JSAE/SAE Powertrains, Energy and Lubricants International Meeting. 10-2 Gobancho, Chiyoda-ku, Tokyo, Japan: Society of Automotive Engineers of Japan, 2023. http://dx.doi.org/10.4271/2023-32-0150.

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<div class="section abstract"><div class="htmlview paragraph">Dimethyl ether (DME) is a highly reactive diesel substitute that can be used as a pilot fuel to ignite low- reactivity methane (CH4) in heavy-duty engines. To optimize the efficiency and emissions of CH4/DME dual-fuel engines, it is crucial to study the fundamental combustion characteristics of DME mixed with methane. This study focuses on the influence of CH4 addition on the low-temperature oxidation (LTO) preparation stage and the thermal ignition (TI) preparation stage of DME in the two-stage ignition process, as these two stages respectively control the ignition delay of the first and second stages. The comparison is made between pure DME and a 50% CH4 and 50% DME blended fuel, operating under thermodynamic conditions representing the engine in- cylinder environment at 30 atm pressure, 650K temperature, and a stoichiometric equivalence ratio. The results show that the addition of methane hardly affects the control mechanism of the two-stage ignition of DME. Specifically, the LTO preparation stage is still promoted by the increase in OH radicals in the DME’s low-temperature oxygenation pathways to form KET, and the second stage is still controlled by the H<sub>2</sub>O<sub>2</sub> loop mechanism. The kinetic analysis also reveals that methane addition can compete for some of the OH radicals in the LTO preparation stage, which has a suppressing effect on ignition. However, in the TI preparation stage, methane can promote the loop reaction of OH→HO<sub>2</sub>→H<sub>2</sub>O<sub>2</sub>→OH and promote ignition. For the operating conditions studied here, although methane consumes a total of 7.24% prior to thermal ignition, it only consumes 0.63% of the total amount in the LTO preparation stage and 1.81% of the total amount in the TI preparation stage. This indicates that methane is mainly consumed in the LTO stage, accounting for 65% of the total methane consumption amount. It can be concluded that the kinetic effect of methane has a relatively small impact on the ignition delay of the DME, at least for the conditions investigated here. In other words, the dilution and thermal effects caused by adding methane are the main reasons for the prolonged time of LTO/TI preparation. Overall, more fundamental research is warranted to understand the role of methane in the two-stage ignition process of DME, which could facilitate the development of CH4/DME dual-fuel engines.</div></div>

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Reports on the topic "Oxygenation Reactions"

1

Banin, Amos, Joseph Stucki, and Joel Kostka. Redox Processes in Soils Irrigated with Reclaimed Sewage Effluents: Field Cycles and Basic Mechanism. United States Department of Agriculture, July 2004. http://dx.doi.org/10.32747/2004.7695870.bard.

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The overall objectives of the project were: (a) To measure and study in situ the effect of irrigation with reclaimed sewage effluents on redox processes and related chemical dynamics in soil profiles of agricultural fields. (b) To study under controlled conditions the kinetics and equilibrium states of selected processes that affect redox conditions in field soils or that are effected by them. Specifically, these include the effects on heavy metals sorption and desorption, and the effect on pesticide degradation. On the basis of the initial results from the field study, increased effort was devoted to clarifying and quantifying the effects of plants and water regime on the soil's redox potential while the study of heavy metals sorption was limited. The use of reclaimed sewage effluents as agricultural irrigation water is increasing at a significant rate. The relatively high levels of suspended and, especially, dissolved organic matter and nitrogen in effluents may affect the redox regime in field soils irrigated with them. In turn, the changes in redox regime may affect, among other parameters, the organic matter and nitrogen dynamics of the root zone and trace organic decomposition processes. Detailed data of the redox potential regime in field plots is lacking, and the detailed mechanisms of its control are obscure and not quantified. The study established the feasibility of long-term, non-disturbing monitoring of redox potential regime in field soils. This may enable to manage soil redox under conditions of continued inputs of wastewater. The importance of controlling the degree of wastewater treatment, particularly of adding ultrafiltration steps and/or tertiary treatment, may be assessed based on these and similar results. Low redox potential was measured in a field site (Site A, KibutzGivat Brenner), that has been irrigated with effluents for 30 years and was used for 15 years for continuous commercial sod production. A permanently reduced horizon (Time weighted averaged pe= 0.33±3.0) was found in this site at the 15 cm depth throughout the measurement period of 10 months. A drastic cultivation intervention, involving prolonged drying and deep plowing operations may be required to reclaim such soils. Site B, characterized by a loamy texture, irrigated with tap water for about 20 years was oxidized (Time weighted average pe=8.1±1.0) throughout the measurement period. Iron in the solid phases of the Givat Brenner soils is chemically-reduced by irrigation. Reduced Fe in these soils causes a change in reactivity toward the pesticide oxamyl, which has been determined to be both cytotoxic and genotoxic to mammalian cells. Reaction of oxamyl with reduced-Fe clay minerals dramatically decreases its cytotoxicity and genotoxicity to mammalian cells. Some other pesticides are affected in the same manner, whereas others are affected in the opposite direction (become more cyto- and genotoxic). Iron-reducing bacteria (FeRB) are abundant in the Givat Brenner soils. FeRB are capable of coupling the oxidation of small molecular weight carbon compounds (fermentation products) to the respiration of iron under anoxic conditions, such as those that occur under flooded soil conditions. FeRB from these soils utilize a variety of Fe forms, including Fe-containing clay minerals, as the sole electron acceptor. Daily cycles of the soil redox potential were discovered and documented in controlled-conditions lysimeter experiments. In the oxic range (pe=12-8) soil redox potential cycling is attributed to the effect of the daily temperature cycle on the equilibrium constant of the oxygenation reaction of H⁺ to form H₂O, and is observed under both effluent and freshwater irrigation. The presence of plants affects considerably the redox potential regime of soils. Redox potential cycling coupled to the irrigation cycles is observed when the soil becomes anoxic and the redox potential is controlled by the Fe(III)/Fe(II) redox couple. This is particularly seen when plants are grown. Re-oxidation of the soil after soil drying at the end of an irrigation cycle is affected to some degree by the water quality. Surprisingly, the results suggest that under certain conditions recovery is less pronounced in the freshwater irrigated soils.

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