Academic literature on the topic 'Hydrogen peroxide direct synthesis'
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Journal articles on the topic "Hydrogen peroxide direct synthesis"
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Szuromi, P. "Direct hydrogen peroxide synthesis." Science 351, no. 6276 (February 25, 2016): 929–31. http://dx.doi.org/10.1126/science.351.6276.929-n.
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Kolehmainen, E., and I. Turunen. "Direct synthesis of hydrogen peroxide in microreactors." Russian Journal of General Chemistry 82, no. 12 (December 2012): 2100–2107. http://dx.doi.org/10.1134/s1070363212120304.
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Ranganathan, Sumanth, and Volker Sieber. "Recent Advances in the Direct Synthesis of Hydrogen Peroxide Using Chemical Catalysis—A Review." Catalysts 8, no. 9 (September 5, 2018): 379. http://dx.doi.org/10.3390/catal8090379.
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Hydrogen peroxide is an important chemical of increasing demand in today’s world. Currently, the anthraquinone autoxidation process dominates the industrial production of hydrogen peroxide. Herein, hydrogen and oxygen are reacted indirectly in the presence of quinones to yield hydrogen peroxide. Owing to the complexity and multi-step nature of the process, it is advantageous to replace the process with an easier and straightforward one. The direct synthesis of hydrogen peroxide from its constituent reagents is an effective and clean route to achieve this goal. Factors such as water formation due to thermodynamics, explosion risk, and the stability of the hydrogen peroxide produced hinder the applicability of this process at an industrial level. Currently, the catalysis for the direct synthesis reaction is palladium based and the research into finding an effective and active catalyst has been ongoing for more than a century now. Palladium in its pure form, or alloyed with certain metals, are some of the new generation of catalysts that are extensively researched. Additionally, to prevent the decomposition of hydrogen peroxide to water, the process is stabilized by adding certain promoters such as mineral acids and halides. A major part of today’s research in this field focusses on the reactor and the mode of operation required for synthesizing hydrogen peroxide. The emergence of microreactor technology has helped in setting up this synthesis in a continuous mode, which could possibly replace the anthraquinone process in the near future. This review will focus on the recent findings of the scientific community in terms of reaction engineering, catalyst and reactor design in the direct synthesis of hydrogen peroxide.
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Khan, Zainab, Nicholas F. Dummer, and Jennifer K. Edwards. "Silver–palladium catalysts for the direct synthesis of hydrogen peroxide." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 376, no. 2110 (November 27, 2017): 20170058. http://dx.doi.org/10.1098/rsta.2017.0058.
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A series of bimetallic silver–palladium catalysts supported on titania were prepared by wet impregnation and assessed for the direct synthesis of hydrogen peroxide, and its subsequent side reactions. The addition of silver to a palladium catalyst was found to significantly decrease hydrogen peroxide productivity and hydrogenation, but crucially increase the rate of decomposition. The decomposition product, which is predominantly hydroxyl radicals, can be used to decrease bacterial colonies. The interaction between silver and palladium was characterized using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and temperature programmed reduction (TPR). The results of the TPR and XPS indicated the formation of a silver–palladium alloy. The optimal 1% Ag–4% Pd/TiO 2 bimetallic catalyst was able to produce approximately 200 ppm of H 2 O 2 in 30 min. The findings demonstrate that AgPd/TiO 2 catalysts are active for the synthesis of hydrogen peroxide and its subsequent decomposition to reactive oxygen species. The catalysts are promising for use in wastewater treatment as they combine the disinfectant properties of silver, hydrogen peroxide production and subsequent decomposition. This article is part of a discussion meeting issue ‘Providing sustainable catalytic solutions for a rapidly changing world’.
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Ntainjua, Edwin N., Simon J. Freakley, and Graham J. Hutchings. "Direct Synthesis of Hydrogen Peroxide Using Ruthenium Catalysts." Topics in Catalysis 55, no. 11-13 (July 25, 2012): 718–22. http://dx.doi.org/10.1007/s11244-012-9866-3.
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Blanco-Brieva, Gema, Frederique Desmedt, Pierre Miquel, Jose Campos-Martin, and Jose Fierro. "Silica Bifunctional Supports for the Direct Synthesis of H2O2: Optimization of Br/Acid Sites and Pd/Br Ratio." Catalysts 12, no. 7 (July 19, 2022): 796. http://dx.doi.org/10.3390/catal12070796.
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We have studied the direct synthesis of hydrogen peroxide using a catalytic system consisting of palladium supported on silica bifunctionalized with sulfonic acid groups and bromide in the absence of acid and halide promoters in solution. Catalysts with several bromide substituents were employed in the catalyst synthesis. The prepared samples were characterized by TXRF, XPS, and hydrogen peroxide decomposition. Catalysts characterization indicated the presence of only palladium (II) species in all of the samples, with similar values for surface and bulk of Pd/Br atomic ratio. The catalysts were tested via direct synthesis, and all samples were able to produce hydrogen peroxide at 313 K and 5.0 MPa. The hydrogen peroxide yield and selectivity changed with the Pd/Br ratio. A decrease in the Pd/Br ratio increases the final hydrogen peroxide concentration, and the selectivity for H2O2 reaches a maximum at a Pd/Br ratio around 0.16 and then decreases. However, the maximum hydrogen peroxide concentration and selectivity occur at slightly different Pd/Br ratios, i.e., resp. 0.4 vs. 0.16.
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Edwards, Jennifer K., James Pritchard, Peter J. Miedziak, Marco Piccinini, Albert F. Carley, Qian He, Christopher J. Kiely, and Graham J. Hutchings. "The direct synthesis of hydrogen peroxide using platinum promoted gold–palladium catalysts." Catal. Sci. Technol. 4, no. 9 (2014): 3244–50. http://dx.doi.org/10.1039/c4cy00496e.
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Inoue, Tomoya, Yoshikuni Kikutani, Satoshi Hamakawa, Kazuma Mawatari, Fujio Mizukami, and Takehiko Kitamori. "Reactor design optimization for direct synthesis of hydrogen peroxide." Chemical Engineering Journal 160, no. 3 (June 2010): 909–14. http://dx.doi.org/10.1016/j.cej.2010.02.027.
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Inoue, Tomoya, Kenichiro Ohtaki, Sunao Murakami, and Sohei Matsumoto. "Direct synthesis of hydrogen peroxide based on microreactor technology." Fuel Processing Technology 108 (April 2013): 8–11. http://dx.doi.org/10.1016/j.fuproc.2012.04.009.
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Crole, David A., Simon J. Freakley, Jennifer K. Edwards, and Graham J. Hutchings. "Direct synthesis of hydrogen peroxide in water at ambient temperature." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 472, no. 2190 (June 2016): 20160156. http://dx.doi.org/10.1098/rspa.2016.0156.
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The direct synthesis of hydrogen peroxide (H 2 O 2 ) from hydrogen and oxygen has been studied using an Au–Pd/TiO 2 catalyst. The aim of this study is to understand the balance of synthesis and sequential degradation reactions using an aqueous, stabilizer-free solvent at ambient temperature. The effects of the reaction conditions on the productivity of H 2 O 2 formation and the undesirable hydrogenation and decomposition reactions are investigated. Reaction temperature, solvent composition and reaction time have been studied and indicate that when using water as the solvent the H 2 O 2 decomposition reaction is the predominant degradation pathway, which provides new challenges for catalyst design, which has previously focused on minimizing the subsequent hydrogenation reaction. This is of importance for the application of this catalytic approach for water purification.
Dissertations / Theses on the topic "Hydrogen peroxide direct synthesis"
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Biasi, Pierdomenico. "Engineering the reaction of hydrogen peroxide direct synthesis." Doctoral thesis, Università degli studi di Padova, 2010. http://hdl.handle.net/11577/3427081.
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Hydrogen peroxide (H2O2) is a versatile environmentally friendly oxidizing agent that has many practical applications. H2O2 has countless qualities and it is one of the world’s most important bulk inorganic chemicals. Most of the world’s H2O2 is produced by auto-oxidation process (AO). The AO process involves indirect oxidation of H2 to yield H2O2. The first commercial anthraquinone (AQ) process was operated by I.G. Farbeinindustrie in Germany during the second world war. The AO process is successfully used to produce most of the world’s H2O2 because it avoids explosive H2/O2 gas mixture.
However AO process suffers from several drawbacks, such as the use of a complex and toxic solvent system, the periodic replacement of costly quinone-derivative due to non-selective hydrogenation, the deactivation of the hydrogenation catalyst, high requirements of energy and intensive process steps for the removal of organic impurities. Also, it is known to have high capital and operating costs, thus it economically viable only for large scale productions (>4*104 tons per year). Therefore, H2O2 is produced in few locations and then transported to the customers. Transportation of H2O2 creates additional safety concerns since concentrated H2O2 can decompose explosively.
A process where H2O2 forms from the direct combination of its elements (H2 and O2) could be preferred, especially for small scale productions at the end-user site, if control of the sequential hydrogenation can be achieved, but none of the presently available processes has solved the productivity vs. safety dilemma.
Traditionally, the attention of the scientists focused on the identification of an active and particularly selective catalyst, overlooking the impact of safety and multiphase issues. Both aspects may benefit from continuous operations and suitable feeding policies, along with kinetics studies as we are currently investigating.
Three reactor set-ups were developed and realized for hydrogen peroxide direct synthesis: two of them are based on batch reactors of different volumes to perform catalytic tests and kinetics studies, and one is based on a novel trickle bed reactor (TBR).
Most of the work presented here is focused on the continuous reactor, far more attractive from an industrial perspective. In the TBR set up different catalysts were chosen to investigate H2O2 direct synthesis. A systematic study on operative conditions was performed, varying liquid and gas flow rates (contact time between liquid,gas and solid phases), changing H2/O2 ratio, investigating conditions for H2O2 decomposition and the effect of pressure. With this work very high values of selectivity were achieved (up to 90%), improving catalytic performances compared to those previously obtained in batch reactor set-ups. The best results were accomplished with a Pd and Au catalyst supported on sulfated zirconia.
Despite an extensive body of research on the direct synthesis process, very little has been published about kinetic rate expressions of the full reaction network, and in this study experimental kinetics in a batch reactor and their relative modeling are treated for the first time.Il perossido di idrogeno è un ossidante “verde” e non tossico, che non genera sottoprodotti inquinanti per l’ambiente, poiché si decompone a dare solamente acqua ed ossigeno. Il perossido di idrogeno viene utilizzato principalmente nelle cartiere come sbiancante, nell’industria tessile e metallurgica, come intermedio nella sintesi chimica, come disinfettante e additivo per detergenti, e molto altro. L’H2O2 viene attualmente prodotto con il processo dell’antrachinone, il quale necessita di numerose operazioni per la produzione e la purificazione del prodotto finale, con il conseguente elevato consumo energetico, a cui sono associati notevoli costi di esercizio, e la formazione di sottoprodotti inquinanti. La sintesi diretta di H2O2 è un’alternativa interessante, che si propone di eliminare i sottoprodotti inquinanti e ridurre drasticamente i costi di impianto e di esercizio, per produzioni su piccola scala direttamente in situ presso l’utilizzatore finale (che non è Berlusconi). In questo modo sarebbe possibile abbattere anche i costi di trasporto e i rischi ad esso connessi. Negli ultimi anni particolare attenzione è stata data al processo di sintesi diretta di acqua ossigenata, tuttavia i lavori pubblicati e brevettati vertevano per lo più sullo sviluppo di un catalizzatore che potesse avere delle caratteristiche tali da favorire la formazione di perossido di idrogeno a dispetto delle reazioni di decomposizione e idrogenazione dello stesso, anch’esse facenti parte del network di reazione. Scarso interesse è invece stato rivolto allo studio sistematico delle condizioni operative e allo sviluppo di un processo continuo. Ad esempio, lo studio in reattori batch non è stato mai approfondito con cinetiche di reazione e con lo studio degli equilibri liquido-vapore che si instaurano all’interno del sistema di reazione. In questo lavoro sono stati sviluppati e realizzati due reattori di tipo batch (di due volumi differenti) e un reattore in continuo: dei due reattori batch, uno è stato utilizzato per testare i catalizzatori e condurre studi preliminari, mentre nell’altro si sono svolti studi di cinetiche di reazione, che sono stati successivamente utilizzati per sviluppare un modello cinetico relativo all’intero network di reazioni. Il reattore continuo, invece, è un reattore a letto fisso (trickle bed reactor) in cui viene caricato il catalizzatore. Un notevole interesse dalle realtà industriali è rivolto all’operazione in continuo, per cui in questo progetto particolare attenzione è stata data allo sviluppo di un tale processo, ottimizzandone le condizioni operative per massimizzare la produzione di acqua ossigenata. Numerosi catalizzatori mono- e bi- metallici sono stati studiati, supportati su diversi materiali, sia inorganici che organici, e per ognuno di essi sono state studiate le migliori condizioni operative. Nel Capitolo 1 è presentato lo stato dell’arte della ricerca sulla sintesi diretta del perossido di idrogeno, e viene spiegato come la ricerca effettuata fin d’ora abbia posto l’attenzione sullo studio di un catalizzatore che potesse essere adatto alla sintesi diretta, trascurando però lo studio reattoristico del sistema impiegato. Nel Capitolo 2 è descritto lo sviluppo dei reattori in seguito utilizzati nella sperimentazione, ed i sistemi di analisi implementati. Vengono presentati gli schemi di impianto e gli studi preliminari condotti sia sui reattori batch, che sul reattore continuo. Il Capitolo 3 affronta temi di cinetica con la relativa modellazione. Sono stati condotti esperimenti di sintesi diretta in un reattore batch ad alta pressione, e da questi dati è stato ricavato un primo approccio di modello cinetico ancora assente in letteratura. Nel Capitolo 4 si è studiato un catalizzatore al palladio su un supporto di ceria sulfatata, con il quale sono stati condotti esperimenti di decomposizione e idrogenazione del perossido di idrogeno. Partendo da questi risultati si è svolto uno studio teso ad identificare le migliori portate di gas e di liquido per ottenere la massima produttività e la massima selettività. Un’altra condizione operativa indagata è stata la pressione ed il suo effetto sulla produzione di acqua ossigenata. Nel Capitolo 5 sono stati scelti 4 catalizzatori a base di palladio, supportati su diversi materiali inorganici. Variando le condizioni operative di sistema si è studiato il comportamento di questi catalizzatori in relazione alla produzione di H2O2 e alla loro selettività. I vari catalizzatori, a seconda del supporto, hanno proprietà differenti e le condizioni operative devono essere ottimizzate di conseguenza per ottenere il massimo rendimento sulla sintesi diretta. Il Capitolo 6 tratta lo studio di catalizzatori bimetallici a base di palladio e oro e catalizzatori a base di solo palladio. Diversi supporti inorganici sono stati utilizzati ed è stato introdotto un nuovo supporto organico. I catalizzatori sono stati confrontati tra di loro variando le condizioni operative di sistema. È stato inoltre studiato l’effetto della concentrazione di idrogeno immesso come reagente e il suo effetto sulla sintesi diretta di H2O2. Il Capitolo 7 riassume i migliori risultati ottenuti e fornisce indicazioni relativamente agli sviluppi futuri. In Appendice è fornito un approccio per la modellazione termodinamica del sistema.
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Melada, Stefano <1974>. "New catalysts for the direct synthesis of hydrogen peroxide." Doctoral thesis, Università Ca' Foscari Venezia, 2005. http://hdl.handle.net/10579/829.
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Edwards, Jennifer Kelly. "Direct synthesis of hydrogen peroxide from hydrogen and oxygen over catalysts containing gold." Thesis, Cardiff University, 2006. http://orca.cf.ac.uk/56194/.
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The direct synthesis of hydrogen peroxide from hydrogen and oxygen over supported gold, palladium and gold palladium catalysts was studied in a high-pressure stirred autoclave containing a stabiliser-free solvent system. The rate of H2O2 synthesis for supported Au catalysts was found to be lower than that of the Pd only catalysts. However, carbon, titania, iron oxide and alumina supported Au-Pd catalysts are significantly more active and selective for H2O2 synthesis than the monometallic catalysts. For silica supported gold-palladium catalysts, the activity was found to scale directly with palladium content and no synergy was observed with gold-palladium catalysts. Gold-palladium catalysts prepared on iron oxide, alumina and titania were all found to form core-shell structures on calcination consisting of a gold core surrounded by a palladium shell. However, on silica and activated carbon the bimetallic catalysts formed homogenous alloys. The activity and selectivity of the catalyst was found to be highly dependant on the reaction conditions employed factors such as catalyst mass, solvent composition, catalyst composition and reaction length had significant effects on the catalyst activity. Modification of the support with a dilute acid prior to metal deposition led to gold-palladium catalysts with >98% selectivity to H2O2 when compared to catalysts prepared on the unmodified support. This increase in catalytic performance corresponded to an increase in metal particle size - indicating that smaller gold-palladium catalysts are highly active and selective for the direct synthesis of hydrogen peroxide. Acid pre-treatment of silica prior to metal deposition led to bimetallic catalysts where the activity did not scale with the palladium content.
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Shaw, Greg. "The direct synthesis of hydrogen peroxide using bimetallic, gold and palladium, supported catalysts." Thesis, Cardiff University, 2013. http://orca.cf.ac.uk/47738/.
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In this thesis the direct synthesis of hydrogen peroxide from hydrogen and oxygen using gold-palladium supported catalysts is described. The direct route presents a greener and sustainable alternative to the current industrial manufacture process. This work aims to meet industrial requirements set by Solvay® which would make the direct process industrially viable. The drawback preventing the requirements being met is the reaction of hydrogen and oxygen over a catalyst can yield water as well as hydrogen peroxide. Once H2O2 is formed, it can be consumed by either reduction or decomposition. Thus, the rates of the subsequent reactions must be minimized to increase the selectivity and therefore H2O2 concentration to a desirable level. Aspects of the catalyst design and reaction variables have been studied over three results chapters. Firstly, the thermal treatment conditions have been altered, ultimately producing a catalyst with no activity to the H2O2 consumption under standard conditions. Switching off H2O2 hydrogenation was concluded to be due to an increase in Pd2+, isolating active Pd0 species. Secondly, active catalysts to both the synthesis and hydrogenation of H2O2 have been produced with no halide; the addition of halide has been shown to decrease hydrogenation activity while maintaining synthesis activity. Finally, a biphasic solvent system and a constant flow of gases through the reaction medium have been examined in order to produce higher H2O2 concentrations. In the former case H2O2 is extracted in-situ from an immiscible organic phase. The production of a 3 wt% H2O2 solution highlights the potential of such a system. In the latter case a semi-continuous flow reactor is utilised increasing the H2O2 concentration up to ca. 1 wt% (from ca. 0.2 wt%). The reactor allowed H2 selectivity and H2O concentration to be measured as a function of time, thus providing greater insight into catalyst activity.
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Wang, Yingyu. "The exploration of less expensive materials for the direct synthesis of hydrogen peroxide." Thesis, Cardiff University, 2014. http://orca.cf.ac.uk/71407/.
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The research presented in this thesis describes the direct synthesis of hydrogen peroxide from H2 and O2 using supported palladium based catalysts. The direct synthesis of hydrogen peroxide offers a more straightforward and sustainable alternative to the current industrial anthraquinone autoxidation (AO) process. Au-Pd bimetallic catalysts have been proved to be highly active for the direct synthesis process. The work presented in this thesis attempted to produce less expensive catalysts through adding cheap secondary metal to Pd as an effective substitute to Au or using an effective preparation for a low metal loading of Au-Pd nanoparticles. In addition, a comprehension of the actual active sites over bimetallic and Pd monometallic particles for H2O2 direct synthesis was also attempted. The first part of this work aims to explain an interesting phenomenon – an increase of activity for H2O2 direct synthesis and a decrease of hydrogenation of H2O2 over carbon supported Ni-Pd bimetallic and Pd only catalysts after both hydrogen peroxide synthesis and storage under ambient conditions. Based on the results of XPS, XRD and CO-chemisorption integrated with previous publications, it was concluded that (i) both the reaction of hydrogen peroxide direct synthesis and catalyst storage led to an decrease of particle dispersion; (ii) relative to the active sites on high energy surfaces/small particles of Pd (0), those on low energy surfaces/large particles are more selective for H2O2 synthesis, as the latter demonstrates lower activity of dissociative adsorption of O2 and H2O2. The role of secondary metal-Ni added to Pd was also investigated for H2O2 direct synthesis in the thesis. For carbon supported Ni/Pd catalysts (including Ni monometallic, Pd monometallic and Ni-Pd bimetallic catalysts), the addition of Ni to Pd enhanced catalytic activity and selectivity for H2O2 synthesis. The results of MP-AES, XPS, XRD and TPR implied that metallic Pd may sit on the top of Ni oxides with a dissolution of metallic Ni in Pd to some degree. Electron transfer from Ni to Pd probably also occurred which was inferred by XPS analysis. The role of Ni in Pd for H2O2 direct synthesis was Preface III also investigated over TiO2 supported catalysts which led to an enhancement of H2O2 productivity, H2 conversion rate and H2O2 selectivity relative to Pd only catalyst. Based on the results of XPS, TPR and STEM, it was concluded that inactive Ni species diluted Pd sites as individual Pd atoms which are the selective active sites for H2O2 direct formation. The next part of the study addressed a modified impregnation method (MIm) for the preparation of Au-Pd nanoparticles. These nanoparticles have been proved previously by STEM which are well dispersed homogeneous particles because of excess amount of Cl- ions in the preparation. As a consequence, the resulted catalyst demonstrated a superior activity than conventional impregnation method (CIm) analogues even the latter loaded with a quintuple metal loading. Through tuning Pd metal loading in 1 wt% Au-Pd and Pd only catalysts for H2O2 direct synthesis, two typical phenomena were observed in general: (i) an enhanced synergistic effect of Au and Pd by MIm than CIm and (ii) a rise of H2O2 productivity based on the mass of Pd loading with the addition of Au in 1 wt% Au-Pd MIm catalysts. As the possible formation of homogeneous Au-Pd alloy, an increase of H2O2 productivity based on Pd with the increase of Au content is probably out of the ensemble effect from the secondary metal.
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Akram, Adeeba. "The direct synthesis of hydrogen peroxide using bimetallic gold and palladium supported catalysts." Thesis, Cardiff University, 2015. http://orca.cf.ac.uk/89293/.
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In this thesis the direct synthesis of hydrogen peroxide (H2O2) from hydrogen and oxygen using gold-palladium supported catalysts was investigated. The direct route represents a greener and sustainable alternative to the current industrial manufacturing process. The main objective of this study was to achieve the industrial requirements of H2O2 yields and selectivity, which would make the direct process industrially viable. In order to reach the required target, two innovative approaches for the direct synthesis of H2O2 were examined. The first part of this thesis was dedicated to the development of a biphasic solvent system comprising an organic alcohol and water. The advantages of this system was highlighted and the effect of reaction variables (such as solvent composition, pressure, reagent ratio, temperature and reaction time) were evaluated using two different catalysts. The identification of two optimum conditions resulted in an important enhancement in the H2O2 yield for the two catalysts examined. By finely tuning the reaction conditions and using two different solvent systems ((i) decan-1-o1-water (ii) diisobutyl carbinol-water) H2O2 concentrations between ~ 0.30 and 28 wt. % were achieved. The second part of this thesis was dedicated to studying the direct gas phase synthesis of H2O2 in a continuous gas flow reactor. Two lab scale flow reactors were designed and built in situ: The first was for studying the direct gas phase synthesis of H2O2 at atmospheric pressure and the second for studying the reaction at pressures above atmospheric. The results demonstrate the direct gas phase synthesis of H2O2 was challenging and the absence of solvent seriously compromises the stability of the H2O2. Despite this, the results demonstrate by using gold-palladium nanoparticles and a mixture of hydrogen and oxygen it is possible to not only oxidise organic molecules in the gas phase but the synthesis rates were high enough to detect H2O2 as a product in a fixed bed gas phase reactor and a temporal analysis of products (TAP) reactor. This observation opens up the possibility of synthesising H2O2 directly in a gas phase reaction.
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Freakley, Simon James. "Investigations into the direct synthesis of hydrogen peroxide and CO oxidation using precious metal catalysts." Thesis, Cardiff University, 2012. http://orca.cf.ac.uk/46829/.
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The direct synthesis of hydrogen peroxide from molecular hydrogen and oxygen represents an attractive atom efficient alternative to the current industrial auto-oxidation process which relies on the sequential oxidation and reduction of an anthraquinone. The first and most widely studied catalysts for this reaction were palladium based however over-hydrogenation of the synthesised hydrogen peroxide is a problem. Recent advances demonstrate that the addition of gold to the catalyst has been shown to significantly improve the productivity of the catalysts by suppressing the hydrogenation and decomposition activity. The work in this thesis shows that tin can be used as a catalyst additive as a direct replacement for gold by a simple impregnation method. By tuning the heat treatments of these bimetallic tin-palladium catalysts it was possible to switch off the competing hydrogenation and decomposition reactions. The construction of a small scale flow system has allowed the independent study of reaction variables and the determination of global kinetics and rate constants for the synthesis and subsequent reactions. It was shown that in a flow system it was the decomposition reaction that had a greater limiting effect on the production of hydrogen peroxide than the hydrogenation reaction. A study was also carried out into CO oxidation using gold / iron oxide catalyst prepared in Cardiff and by Prof. Haruta’s group in Tokyo. These catalysts underwent extensive tests to try and identify the active species of the catalyst. Detailed testing and STEM characterisation of the samples identified the possibility of different mechanisms operating at different temperatures and no correlation between the nanoparticle population and activity at sub ambient temperature could be made which challenges the hypothesis that nanoparticles are the most active species and that sub nanometer clusters may be the active species at low temperatures.
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Sterchele, Stefano. "Polymer Supported Heterogenous Catalysts for Direct Synthesis of Hydrogen Peroxide in Absence of Selectivity Enhancers." Doctoral thesis, Università degli studi di Padova, 2013. http://hdl.handle.net/11577/3423426.
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The research program developed during the Ph.D. School is focused on the study of metal catalysts supported on cross-linked functional polymers (CFPs) for the direct synthesis of hydrogen peroxide.
In the last twenty years this compound has become a commodity with a constant increasing demand because of its strong oxidant properties and the formation of water as the reduction byproduct. In particular, H2O2 is widely employed as environmentally-friendly bleaching and cleaning agent.
The best alternative to the current process, in particular for the small-scale production, is certainly the synthesis of H2O2 from the elements (direct synthesis). This is generally carried out with a heterogeneous catalyst under triphase condition. For safety reasons, the hydrogen-oxygen mixtures, according to the wide explosion range, are properly diluted with an inert gas, usually nitrogen or carbon dioxide.
The catalyst is generally composed by one or more nanostructured noble metals, supported on an inorganic solid, carbon or organic materials. It is well known in literature that the presence in solution of additives, like halides (bromide and chloride) and mineral acids, dramatically improves the catalytic performances, in particular the selectivity towards H2O2. However, the use of these additives presents some process drawbacks, such as corrosion, leaching of catalyst, etc, which do not allow the straightforward use of the H2O2 solutions obtained from the direct synthesis. It is therefore mandatory a further step of purification to remove the additives. As a consequence, in order to evaluate the effective performance of the catalysts,the research activity during this PhD thesis aim at the investigation of catalytic systems free of selectivity enhancers. In particular, their presence has been avoided not only in the reaction mixture, but also during the preparation of the catalysts.
In the frame of this PhD Thesis, a few sets of mono- and bimetallic catalysts, supported on the commercially available macroreticular resin, Laxness Lewatit K2621, have been studied in detail. This work has been performed in a research group with a long standing experience in the investigation of polymer-based metal catalysts for industrially relevant reactions and, for a few months, in the Laboratory of Industrial Chemistry and Reaction Engineering of Akademi Prof. Tapio Salmi (Department of Chemical Engineering, Process Chemistry Centre, Åbo Akademi University, Turku, Finland) for the detailed study of the catalysts performances.
The research program is based on the synthesis, the characterisation and the investigation of the catalytic behaviour of the catalysts, obtained by carefully controlling a few essential parameters during the synthesis, such as the nature of the precursor, the reducing agent and the experimental conditions. These three key-points remarkably affect the features of metal nanoparticles (size distribution, difective structure, etc...) and, hence, the behaviour of the catalysts. In particular, the use of tetraaminepalladium (II) sulfate as the metal precursor and the reductive treatment with hydrogen under mild condition lead to a catalyst with noteworthy catalytic performances, specially a remarkable selectivity (70%).
The investigation has also included four libraries of bimetallic materials, Au/Pd and Pt/Pd catalysts based on K2621, obtained as followed:
- by keeping constant the content of palladium (1 wt.%) and changing the one of the second metal (0.1, 0.25, 0.5, 1 wt.% of Pt or Au);
- by treating the material with two different reduction protocols (formaldehyde under reflux temperature and hydrogen (5 bar) under 60°C ).
The catalytic results clearly show that the addition of platinum and gold to palladium improves the catalytic performances, although apparently with different mechanisms. The best catalysts are consistent with the empiric trends so far reported in literature.
Finally a new class of mesoporous cross-linked polymers, featured by high surface area at the dry state, has been studied. This non-commercial polymer, quite promising as catalytic support, has been investigated in details and used for the preparation of palladium nanoparticles. This material, in view of its peculiar morphology, shows unique catalytic properties, exhibiting simultaneously a modest activity and a remarkable (70 – 80) and constant H2O2 selectivity: this unique features makes this catalyst a good candidate for a mechanistic study of the direct synthesis of hydrogen peroxide.Il programma di ricerca sviluppato durante il triennio della Scuola di Dottorato si focalizza sullo studio di catalizzatori metallici supportati su polimeri reticolati funzionali per la sintesi diretta di perossido di idrogeno. Questa sostanza, diventata negli ultimi anni una commodity con un mercato in costante crescita, è massicciamente utilizzata come forte ossidante e, in particolare, come sbiancante , in quanto è compatibile con l'ambiente. Il processo di sintesi di H2O2 che in prospettiva può diventare alternativo all'attuale per produzioni su piccola scala è la sintesi a partire dagli elementi (sintesi diretta). Questa reazione viene normalmente condotta con un catalizzatore eterogeneo in condizioni trifasiche. Inoltre le miscele idrogeno-ossigeno vengono debitamente diluite con un gas inerte, a causa dell'ampio intervallo di esplosività dei due gas. Il catalizzatore è normalmente costituito da uno o più metalli nobili nanostrutturati, supportati su un solido inorganico, carbone o matrici organiche. È noto in letteratura che l'uso di additivi in soluzione, come alogenuri (bromuri e cloruri) e di acidi minerali, migliora drasticamente le prestazioni catalitiche, in particolare la selettività verso H2O2. Queste stesse sostanze sono però indesiderate, in quanto non consentono l'uso diretto della soluzione di H2O2 ottenuta, se non previa rimozione degli additivi e in aggiunta creano problemi dal punto di vista impiantistico (corrosione, leaching, ecc). L'intero studio è stato concepito con lo scopo di indagare i sistemi catalitici, in modo da evitare qualsiasi interferenza dovuta a questi additivi, evitandone quindi la presenza, non solo durante le prove catalitiche, ma anche in fase di sintesi, attraverso l'accurata scelta dei precursori metallici. In questo triennio, sono stati studiati alcuni materiali mono- e bimetallici supportati su una resina macroreticolare commerciale, Laxness Lewatit K2621. Il lavoro è stato svolto nell'ambito di un gruppo di ricerca già attivo da anni nello studio di catalizzatori metallici supportati su polimeri per reazioni di interesse industriale e per alcuni mesi presso i laboratori di ricerca del Prof. Tapio Salmi (Department of Chemical Engineering, Process Chemistry Centre, Laboratory of Industrial Chemistry and Reaction Engineering Åbo Akademi University, Turku, Finland) per la realizzazione delle prove catalitiche. L'indagine si è incentrata sulla sintesi, sulla caratterizzazione e sullo studio delle prestazioni catalitiche di materiali preparati variando alcuni importanti parametri di sintesi, quali il tipo di precursore, l'agente riducente e le condizioni sperimentali. Questi hanno una grande ripercussione sulle caratteristiche delle nanoparticelle metalliche (distribuzione dimensionale, difettività, ecc), le quali incidono a loro volta pesantemente sulle proprietà catalitiche. In particolar modo, l'uso di un complesso tetraamminico di palladio (II) e la riduzione in condizioni blande con idrogeno impartiscono al materiale notevoli proprietà catalitiche, caratterizzate da una rimarchevole selettività (70%), inedita in letteratura. Lo studio ha preso in considerazione anche quattro librerie di catalizzatori bimetallici Au/Pd a Pt/Pd supportate sulla stessa resina usata in precedenza, ottenute sia mantenendo fissa la quantità in peso di palladio e variando quella del secondo metallo, che utilizzando due distinti protocolli di riduzione. I risultati catalitici portano a supporre che platino e oro aumentino le prestazioni catalitiche con meccanismi tra loro molto differenti. Inoltre, la composizione dei migliori catalizzatori bimetallici preparati nell'ambito di questo lavoro di Tesi risulta in linea con le indagini fenomenologiche riportate in letteratura. Durante il periodo di dottorato, è stato preparato e studiato un polimero reticolato non commerciale ad elevata porosità e successivamente utilizzato come supporto per il catalizzatore. Il materiale risultante ha mostrato peculiari proprietà catalitiche esibisce una bassa conversione di idrogeno ma un'elevata selettività in H2O2 con valori nell'intervallo tra 70 e 80%. Queste caratteristiche lo pongono come un buon candidato per uno studio meccanicistico più approfondito della reazione.
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Pritchard, James. "Preparation and characterisation of gold and palladium based catalysts for the direct synthesis of hydrogen peroxide." Thesis, Cardiff University, 2012. http://orca.cf.ac.uk/47059/.
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I The research presented in this thesis describes the direct synthesis of hydrogen peroxide from H2 and O2 using supported gold-palladium based catalysts. The direct synthesis process offers a green and sustainable approach compared to the anthraquinone autoxidation (AO) process, which is currently used on an industrial scale to produce >95% H2O2 worldwide. The work presented in this thesis is an attempt to examine the direct synthesis process in terms of determining optimum catalyst compositions for potential scale-up in the near-future. The primary aim of this investigation is centred on catalyst design and characterisation. The first part of this work is a catalyst optimisation study for 2.5 wt% Au-2.5 wt% Pd/TiO2, and involved changing the amount of water used in the catalyst preparation, in this case wet impregnation. It was found that the addition of small amounts of water resulted in approximately 100% enhancement in activity for TiO2-supported catalysts but not for carbonsupported Au-Pd catalysts. The rate of Au/Pd uptake was contrasted and it was determined that the isoelectric point of the support was highly influential. While the activity can be enhanced for TiO2-supported catalysts, both catalyst nanostructure and stability were detrimentally affected by the addition of water during the impregnation step. The second part of this work is focussed on understanding the precise nature of the acid pre-treatment effect, where treatment of a carbon support in dilute nitric acid prior to the impregnation of Au and Pd precursors can result in the complete switching-off of sequential H2O2 hydrogenation activity over the catalyst. Characterisation and heat treatment studies gave an improved understanding of the relationship between Au/Pd and the carbon support. The next part of the study addresses the use of a colloidal immobilisation method to pre-fabricate Au-Pd ‘designer’ nanoparticles onto supports and is accompanied by extensive advanced aberration corrected electron microscopy studies. The effect of acid pre-treating silica based supports is then considered for catalysts prepared by wet-impregnation, specifically the fact that acid pre-treatment of silica is required to induce synergy between Au and Pd metals for the direct synthesis of hydrogen peroxide. The final part of this work considers the effect of introducing a third metal into the catalyst design, specifically the addition of Pt to Au/Pd compositions. An extensive catalyst screening study is undertaken for Au-Pd-Pt/CeO2 catalysts.
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Crole, David Alexander. "The direct synthesis of hydrogen peroxide in water at ambient temperature : a study of reaction conditions, catalyst design and implementation." Thesis, Cardiff University, 2017. http://orca.cf.ac.uk/107580/.
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The research presented in this thesis focuses on the process of direct synthesis of hydrogen peroxide from molecular hydrogen and oxygen. This reaction potentially offers an approach which is greener and more sustainable when compared to the current industrial indirect auto-oxidation process. The work presented herein examines some of the key factors in determining the viability of the process in a water solvent at ambient temperature, conditions which would represent a very economically and environmentally attractive option, if feasible. The first part of this thesis investigates the ways in which changing reaction conditions affects the fundamental reaction processes of the direct synthesis reaction – synthesis of hydrogen peroxide and its subsequent degradation by decomposition and hydrogenation. It was found that moving to a water solvent and ambient temperature results in significantly lower yields and greater degradation comparative to previously used water/methanol solvents and 2°C reactions. The second part of this thesis explores the design of catalysts which are active for the direct synthesis of hydrogen peroxide while limiting degradation activity, to increase the yield in water at ambient temperature. A series of supported metal catalysts of the nominal formulation 0.5 wt. % Pd - 4.5 wt. % ‘base metal’ were prepared and treated with a cyclic oxidative-reductive-oxidative heat treatment. This produced highly stable catalysts with activity for the synthesis of hydrogen peroxide, but low to no activity for both decomposition and hydrogenation pathways. These catalysts also fulfilled a secondary aim of producing economically attractive catalysts due to the low loadings of precious metals used. The third and final part of this thesis studies the implementation of these highly selective catalysts in both gas and gas/liquid phase flow reactors. The production of hydrogen peroxide in a gas phase flow system is shown to be attainable although most likely not a commercially viable option. The direct synthesis of hydrogen peroxide in a gas/liquid flow system is shown to proceed with selectivities greater than those previously reported for different catalysts under similar conditions. Tests also show that hydrogen peroxide can be produced under ‘real world’ conditions of high flow rates, a hard water solvent and a dilute hydrogen in air gas mix. These studies could be used to inform future work on high throughput water cleaning technologies.
Books on the topic "Hydrogen peroxide direct synthesis"
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A, Herrmann W., and Adam Waldemar, eds. Organic peroxygen chemistry. Berlin: Springer-Verlag, 1993.
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British Food Manufacturing Industries Research Association., ed. USA. Indirect additives: Polymers. Direct additives : GRAS status of hydrogen peroxide and benzoyl peroxide. GRAS status of sulphiting agents tartrazine (FD & C Yellow no.5) Labelling : declaration of sulphiting agents.. Leatherhead: British Food Manufacturing Industries Research Association, 1986.
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Pizey, J. S. Synthetic Reagents: Chloramine-T, Hydrogen Peroxide, Polyphosphoric Acid (Ellis Horwood Series in Chemical Science). Ellis Horwood Ltd, 1985.
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Rapid Production of Mixed-Base Hydrogen Peroxide by Direct-Contact Liquefied Nitrogen Evaporation; Process Design, Scale-Up, and Validation. Storming Media, 2004.
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Foyle, Victor Peter *. Photoreduction of polymeric-gel-bound anthraquinone: its products, reaction scheme, and application to the photocatalytic synthesis of hydrogen peroxide. 1991.
Find full textBook chapters on the topic "Hydrogen peroxide direct synthesis"
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Wendlandt, Alison E., and Shannon S. Stahl. "Quinones in Hydrogen Peroxide Synthesis and Catalytic Aerobic Oxidation Reactions." In Liquid Phase Aerobic Oxidation Catalysis: Industrial Applications and Academic Perspectives, 219–37. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2016. http://dx.doi.org/10.1002/9783527690121.ch14.
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Remias, Joseph E., and Ayusman Sen. "Bimetallic Oxidation Catalysts: Hydrogen Peroxide Generation and Its Use in Hydrocarbon Oxidation." In Multimetallic Catalysts in Organic Synthesis, 187–99. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527603557.ch8.
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Conte, Valeria, and Fulvio Di Furia. "Peroxometal Complexes Derived from Hydrogen Peroxide. Some Applications in Organic Synthesis." In Catalysis by Metal Complexes, 223–52. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-017-0984-2_7.
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Barton, D. H. R. "The Functionalization of Saturated Hydrocarbons by Gif Chemistry. Part 1. Use of Superoxide and of Hydrogen Peroxide. Part 2. Use of t-Butylhydroperoxide (TBHP)." In Chemical Synthesis, 589–99. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-0255-8_26.
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McKenna, Susan M., and Kelvin J. A. Davies. "Bacterial Killing by Phagocytes: Potential Role(s) of Hypochlorous Acid and Hydrogen Peroxide in Protein Turnover, DNA Synthesis, and RNA Synthesis." In Oxygen Radicals in Biology and Medicine, 829–32. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4684-5568-7_133.
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Winrow, V. R., A. Watson, S. L. Harley, and D. R. Blake. "Hydrogen peroxide-induced synthesis of the 32kDa stress protein (HO-1) in endothelial cells is serum dependent." In Oxidative Stress, Cell Activation and Viral Infection, 91–100. Basel: Birkhäuser Basel, 1994. http://dx.doi.org/10.1007/978-3-0348-7424-3_10.
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Taber, Douglass. "The Zakarian Synthesis of ( + )-Pinnatoxin A." In Organic Synthesis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199764549.003.0097.
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( + )-Pinnatoxin A 3, isolated from the shellfish Pinna muricata, is thought to be a calcium channel activator. A key transformation in the synthesis of 3 reported (J. Am. Chem. Soc . 2008, 130, 3774) by Armen Zakarian, now at the University of California, Santa Barbara, was the diastereoselective Claisen rearrangement of 1 to 2. The alcohol portion of ester 1 was derived from the aldehyde 4, prepared from D-ribose. The absolute configuration of the secondary allylic alcohol was established by chiral amino alcohol catalyzed addition of diethyl zinc to the unsaturated aldehyde 5. The acid portion of the ester 1 was prepared from (S)-citronellic acid, by way of the Evans imide 7. Methylation proceeded with high diasterocontrol, to give 8. Functional group manipulation provided the imide 9. Alkylation then led to 10, again with high diastereocontrol. In each case, care had to be taken in the further processing of the α-chiral acyl oxazolidinones. Direct NaBH4 reduction of 8 delivered the primary alcohol. To prepare the acid 10, the alkylated acyl oxazolidinone was hydrolyzed with alkaline hydrogen peroxide. On exposure of the ester 1 to the enantiomerically-pure base 11, rearrangement proceeded with high diastereocontrol, to give the acid 2. This outcome suggests that deprotonation proceeded to give the single geometric form of the enolate, that was then trapped to give specifically the ketene silyl acetal 12. This elegant approach is dependent on both the ester 1 and the base 11 being enantiomerically pure. The carbocyclic ring of pinnatoxin A 3 was assembled by intramolecular aldol condensation of the dialdehyde 11. This outcome was remarkable, in that 11 is readily epimerizable, and might also be susceptible to β-elimination. Note that the while the diol corresponding to 11 could be readily oxidized to 11 under Swern conditions, attempts to oxidize the corresponding hydroxy aldehyde were not fruitful.
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Taber, Douglass F. "Reactions of Alkenes." In Organic Synthesis. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780190200794.003.0030.
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Fung-E Hong of the National Chung Hsing University devised (Adv. Synth. Catal. 2011, 353, 1491) a protocol for the oxidative cleavage of an alkene 1 (or an alkyne) to the carboxylic acid 2. Patrick H. Dussault of the University of Nebraska found (Synthesis 2011, 3475) that Na triacetoxyborohydride reduced the methoxy hydroperoxide from the ozonolysis of 3 to the aldehyde 4. Reductive amination of 4 can be effected in the same pot with the same reagent. Philippe Renaud of the University of Bern used (J. Am. Chem. Soc. 2011, 133, 5913) air to promote the free radical reduction to 6 of the intermediate from the hydroboration of 5. Robert H. Grubbs of Caltech showed (Org. Lett. 2011, 13, 6429) that the phosphonium tetrafluoroborate 8 prepared by hydrophosphonation of 7 could be used directly in a subsequent Wittig reaction. Dominique Agustin of the Université de Toulouse epoxidized (Adv. Synth. Catal. 2011, 353, 2910) the alkene 9 to 10 without solvent other than the commercial aqueous t-butyl hydroperoxide. Justin M. Notestein of Northwestern University effected (J. Am. Chem. Soc. 2011, 133, 18684) cis dihydroxylation of 9 to 11 using 30% aqueous hydrogen peroxide. Chi-Ming Che of the University of Hong Kong devised (Chem. Commun. 2011, 47, 10963) a protocol for the anti-Markownikov oxidation of an alkene 12 to the aldehyde 13. Aziridines such as 14 are readily prepared from alkenes. Jeremy B. Morgan of the University of North Carolina Wilmington uncovered (Org. Lett. 2011, 13, 5444) a catalyst that rearranged 14 to the protected amino alcohol 15. A monosubstituted alkene 16 is particularly reactive both with free radicals and with coordinately unsaturated metal centers. A variety of transformations of monosubstituted alkenes have been reported. Nobuharu Iwasawa of the Tokyo Institute of Technology employed (J. Am. Chem. Soc. 2011, 133, 12980) a Pd pincer complex to catalyze the oxidative monoborylation of 16 to give 17. The 1,1-bis boryl derivatives could also be prepared. Professor Renaud effected (J. Am. Chem. Soc. 2011, 133, 13890) radical addition to 16 leading to the terminal azide 18.
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Matsumoto, K., T. Katsuki, and I. W. C. E. Arends. "With Hydrogen Peroxide." In Stereoselective Synthesis 1 Stereoselective Reactions of Carbon—Carbon Double Bonds, 1. Georg Thieme Verlag KG, 2011. http://dx.doi.org/10.1055/sos-sd-201-00042.
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Sheldon, R. A. "Tungsten- and Vanadium-Catalyzed Oxidations with Hydrogen Peroxide." In Water in Organic Synthesis, 1. Georg Thieme Verlag KG, 2012. http://dx.doi.org/10.1055/sos-sd-206-00487.
Full textConference papers on the topic "Hydrogen peroxide direct synthesis"
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Makertihartha, I. G. B. N., P. T. Dharmawijaya, M. Zunita, and I. G. Wenten. "Direct synthesis of hydrogen peroxide using in-situ selective layer." In INTERNATIONAL SEMINAR ON FUNDAMENTAL AND APPLICATION OF CHEMICAL ENGINEERING 2016 (ISFAChE 2016): Proceedings of the 3rd International Seminar on Fundamental and Application of Chemical Engineering 2016. Author(s), 2017. http://dx.doi.org/10.1063/1.4982268.
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Lu, Xu, Sen Wang, and Zhi Fang. "Synthesis of hydrogen peroxide by underwater bubbling multi-mode discharge." In 2021 IEEE International Conference on Plasma Science (ICOPS). IEEE, 2021. http://dx.doi.org/10.1109/icops36761.2021.9588481.
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Rosli, Nur Ratasha Alia Md, Faizal Mohamed, Cheong Kai Heng, Irman Abdul Rahman, Ainee Fatimah Ahmad, and Hur Munawar Kabir Mohamad. "Synthesis and radiosensitization properties of hydrogen peroxide and sodium hyaluronate complex." In THE 2014 UKM FST POSTGRADUATE COLLOQUIUM: Proceedings of the Universiti Kebangsaan Malaysia, Faculty of Science and Technology 2014 Postgraduate Colloquium. AIP Publishing LLC, 2014. http://dx.doi.org/10.1063/1.4895175.
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Xue Wang, Chenguo Hu, Yufeng Xiong, Xiaoshan He, Yi Xi, and Chuanhui Xia. "Synthesis of functional carbon nanospheres and amperometric sensing of hydrogen peroxide." In 2010 IEEE 3rd International Nanoelectronics Conference (INEC). IEEE, 2010. http://dx.doi.org/10.1109/inec.2010.5425043.
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Luo, L., Y. Li, J. Qi, L. Han, D. Deng, and J. Wang. "EC1.3 - Synthesis of ZnMn2O4 microspheres for electrochemical sensing of hydrogen peroxide." In 17th International Meeting on Chemical Sensors - IMCS 2018. AMA Service GmbH, Von-Münchhausen-Str. 49, 31515 Wunstorf, Germany, 2018. http://dx.doi.org/10.5162/imcs2018/ec1.3.
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Ando, Yuji, and Tadayoshi Tanaka. "Proposal of Simultaneous Production Method of Hydrogen and Hydrogen Peroxide From Water Using Solar Photo-Electrochemistry." In ASME 2003 International Solar Energy Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/isec2003-44203.
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Authors have proposed a new hydrogen production system that simultaneously synthesizes hydrogen and hydrogen peroxide from water by electrochemical reaction. Experimental apparatus of this system is composed of a hydrogen electrode with platinum mesh, a hydrogen peroxide electrode with carbon material and an electrolyte with Nafion®. In this paper, the superiority of this system is outlined. In addition, the experimental results of electrolytic synthesis of hydrogen and hydrogen peroxide from water are reported. Furthermore, the possibility of the system that synthesizes hydrogen and hydrogen peroxide from water by the photochemical reaction using solar radiation is also discussed.
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Ferreira, Irlon M., Rafael D. C. Gallo, Gleison A. Casagrande, Lucas Pizzuti, and Cristiano Raminelli. "Ultrasound-promoted iodination of aromatic compounds in the presence of iodine and hydrogen peroxide in water." In 14th Brazilian Meeting on Organic Synthesis. São Paulo: Editora Edgard Blücher, 2013. http://dx.doi.org/10.5151/chempro-14bmos-r0180-2.
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Haripriya, H., and R. S. Rimal Isaac. "One step synthesis of polyvinylpyrrolidone coated silver nanoparticles for the detection of hydrogen peroxide." In PROCEEDINGS OF ADVANCED MATERIAL, ENGINEERING & TECHNOLOGY. AIP Publishing, 2020. http://dx.doi.org/10.1063/5.0019359.
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Bhagyaraj, Sneha, and Igor Krupa. "Alginate-Mediated Synthesis of Hetero-Shaped Silver Nanoparticles and their Hydrogen Peroxide Sensing ability." In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0042.
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Silver nanoparticles have been the focus of extensive research for many decades due to their unique physical, chemical and electrical properties. Introducing new environmentally benign methods for the synthesis of silver nanoparticles is of great interest in the research community. In this work we propose a new method for the simple synthesis of stable heterostructured biopolymer (sodium alginate)-capped silver nanoparticles (Ag-NPs) based on green chemistry.The as-prepared nanoparticles were characterized using the ultraviolet–visible (UV–Vis) absorption spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and Dynamic light scattering (DLS) techniques. The results showed that the as-prepared Ag-NPs have a heterostructured morphology with particle size in the range 30 ± 18 – 60 ± 25 nm, showing a zeta potential of -62 mV. The silver nanoparticle formation was confirmed from UV-Vis spectra showing 424 nm as maximum absorption. The particle size and crystallinity of the as- synthesized nanoparticles were analyzed using TEM and XRD measurements respectively. FTIR spectra confirmed the presence of alginate as capping agent to stabilize the nanoparticles. The Ag-NPs also showed excellent sensing capability, with a linear response to hydrogen peroxide spanning a wide range of concentrations from 10-1 – 10-7 M, which indicates their high potential for water treatment applications, such as pollution detection and nanofiltration composites.
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Wen, C. Y., A. S. Yang, and J. W. Tseng. "Application of Valve-Less Impedance Pumps to a Direct Sodium Borohydride–Hydrogen Peroxide Fuel Cell." In ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting collocated with the ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/fedsm2014-21836.
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In this study, two novel valve-less impedance pumps are applied, for the first time, in the liquid fuel supply of a Direct Sodium Borohydride–Hydrogen Peroxide Fuel Cell (DBHPFC). This valve-less pump prevents the pump corrosion and serves appropriately to reduce the volume and weight of fuel cell systems. It comprises an amber latex rubber tube, connected at both ends to rigid stainless steel tubes of different acoustic impedance, and a simple actuation mechanism which combines a small DC motor and a cam. The motor activated cam periodically compresses the elastic tube at a position asymmetric from the tube ends. Traveling waves, emitted from the compression, combine with reflected waves at the impedance-mismatched rubber tube/stainless tube interfaces. The resulting wave interference creates a pressure gradient and generates a net flow. A DBHPFC with the active area of 25 cm2 is constructed. It is shown that the maximum pumping rate can achieve 30 ml/min with the DBHPFC connected. The corresponding maximum power and current are 13.0 W and 25.5 A, respectively. Specific power, volumetric power density, and back work ratio of the DBHPFC using this pumping method are shown superior to those of the other pumping configuration with the peristaltic pumps.
Reports on the topic "Hydrogen peroxide direct synthesis"
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Hurley, James A., Lixiong Li, Timothy A. Spears, Jr Nichols, Owens Robert K., and Hugh M. Rapid Production of Mixed-Base Hydrogen Peroxide by Direct-Contact Liquefied Nitrogen Evaporation; Process Design, Scale-Up, and Validation. Fort Belvoir, VA: Defense Technical Information Center, January 2004. http://dx.doi.org/10.21236/ada422994.
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Pell, Eva J., Sarah M. Assmann, Amnon Schwartz, and Hava Steinberger. Ozone Altered Stomatal/Guard Cell Function: Whole Plant and Single Cell Analysis. United States Department of Agriculture, December 2000. http://dx.doi.org/10.32747/2000.7573082.bard.
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Original objectives (revisions from original proposal are highlighted) 1. Elucidate the direct effects O3 and H2O2 on guard cell function, utilizing assays of stomatal response in isolated epidermal peels and whole cell gas exchange. 2. Determine the mechanistic basis of O3 and H2O2 effects on the plasma membrane through application of the electrophysiological technique of patch clamping to isolated guard cells. 3. Determine the relative sensitivity of Israeli cultivars of economically important crops to O3 and determine whether differential leaf conductance responses to O3 can explain relative sensitivity to the air pollutant: transfer of technological expertise to Israel. Background to the topic For a long time O3 has been known to reduce gas exchange in plants; it has however been unclear if O3 can affect the stomatal complex directly. Ion channels are essential in stomatal regulation, but O3 has never before been shown to affect these directly. Major conclusions, solution, achievements 1. Ozone inhibits light-induced stomatal opening in epidermal peels isolated from Vicia faba, Arabidopsis thaliana and Nicotiana tabacum in V. faba plants this leads to reduced assimilation without a direct effect on the photosynthetic apparatus. Stomatal opening is more sensitive to O3 than stomatal closure. 2. Ozone causes inhibition of inward K+ channels (involved in stomatal opening) while no detectable effect is observed o the outward K+ channels (stomatal closure). 3. Hydrogen peroxide inhibits stomatal opening and induces stomatal closure in epidermal peels isolated from Vicia faba. 4. Hydrogen peroxide enhances stomatal closure by increasing K+ efflux from guard cells via outward rectifying K+ channels. 5. Based on epidermal peel experiments we have indirectly shown that Ca2+ may play a role in the guard cell response to O3. However, direct measurement of the guard cell [Ca2+]cyt did not show a response to O3. 6. Three Israeli cultivars of zucchini, Clarita, Yarden and Bareqet, were shown to be relatively sensitive to O3 (0.12 ml1-1 ). 7. Two environmentally important Israeli pine species are adversely affected by O3, even at 0.050 ml1-1 , a level frequently exceeded under local tropospheric conditions. P. brutia may be better equipped than P. halepensis to tolerate O3 stress. 8. Ozone directly affects pigment biosynthesis in pine seedlings, as well as the metabolism of O5 precursors, thus affecting the allocation of resources among various metabolic pathways. 9. Ozone induces activity of antioxidant enzymes, and of ascorbate content i the mesophyll and epidermis cells of Commelina communis L. Implications, both scientific and agricultural We have improved the understanding of how O3 and H2O2 do affect guard cell and stomatal function. We have shown that economical important Israeli species like zucchini and pine are relatively sensitive to O3.