Academic literature on the topic 'Heating; Chemical syntheses'
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Journal articles on the topic "Heating; Chemical syntheses"
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Whittaker, A. G., and D. M. P. Mingos. "The Application of Microwave Heating to Chemical Syntheses." Journal of Microwave Power and Electromagnetic Energy 29, no. 4 (January 1994): 195–219. http://dx.doi.org/10.1080/08327823.1994.11688249.
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Auwal, Ismail Alhassan, Fitri Khoerunnisa, Florent Dubray, Svetlana Mintova, Tau Chuan Ling, Ka-Lun Wong, and Eng-Poh Ng. "Effects of Synthesis Parameters on the Crystallization Profile and Morphological Properties of SAPO-5 Templated by 1-Benzyl-2,3-Dimethylimidazolium Hydroxide." Crystals 11, no. 3 (March 12, 2021): 279. http://dx.doi.org/10.3390/cryst11030279.
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The formation of SAPO-5 molecular sieves is studied under hydrothermal conditions in the presence of a new templating agent, 1-benzyl-2,3-dimethylimidazolium hydroxide ([bzmIm]OH). The syntheses were carried out by varying the synthesis parameters, viz. crystallization temperature, heating time and reactants molar composition (SiO2, Al2O3, P2O5, [bzmIm]+, H2O) in order to investigate the role of each synthesis parameter on the formation of SAPO-5. The results showed that these synthesis parameters had significant influences on the entire crystallization process (induction, nucleation, crystal growth, and Ostwald ripening) and physicochemical properties of SAPO-5 (morphology and crystal size). Moreover, this study also demonstrated a fast hydrothermal synthesis approach where a SAPO-5 molecular sieve with hexagonal prism morphology could be crystallized within 10 h instead of days using a novel [bzmIm]OH heterocyclic template, thus offering an alternative route for synthesizing zeolite-like materials for advanced applications.
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Chen, Chu Yang, Xu Chuan Jiang, Shi Xian Xiong, and Ai Bing Yu. "Shape-Controlled Syntheses of Silver Nanoparticles: Role of the Seeds." Materials Science Forum 654-656 (June 2010): 2402–5. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.2402.
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Precious metallic nanoparticles have attracted considerable attention because of their unique properties (optical, electronic, and chemical properties) and potential applications in many areas such as optical probes, biochemical sensors, and surface enhanced Raman Spectrum. Despite many successes in synthesis of anisotropic nanoparticles (rods, plates), some limitations still exist in generating monodispersed silver nanoparticles. This study intends to elucidate the influence of crystalline seeds on the shape, size, and size distribution of nanoparticles through a seed-mediated method. The crystalline seeds can be modified by using different ways, such as heating treatment and oxidative etching. The shape and size of the generated particles will be characterized by TEM, and the particle formation and growth is tracked by UV-vis spectrometry. The findings would be useful for the shape-controlled synthesis of metal nanoparticles for desired functional properties.
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Rodríguez-Padrón, Daily, Alina M. Balu, Antonio A. Romero, and Rafael Luque. "New bio-nanocomposites based on iron oxides and polysaccharides applied to oxidation and alkylation reactions." Beilstein Journal of Organic Chemistry 13 (September 21, 2017): 1982–93. http://dx.doi.org/10.3762/bjoc.13.194.
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Polysaccharides from natural sources and iron precursors were applied to develop new bio-nanocomposites by mechanochemical milling processes. The proposed methodology was demonstrated to be advantageous in comparison with other protocols for the synthesis of iron oxide based nanostructures. Additionally, mechanochemistry has enormous potential from an environmental point-of-view since it is able to reduce solvent issues in chemical syntheses. The catalytic activity of the obtained nanocatalysts was investigated in both the oxidation of benzyl alcohol to benzaldehyde and in the alkylation of toluene with benzyl chloride. The microwave-assisted oxidation of benzyl alcohol reached 45% conversion after 10 min. The conversion of the alkylation of toluene in both microwave-assisted and conventional heating methods was higher than 99% after 3 min and 30 min, respectively. The transformation of benzyl alcohol and toluene into valuable product in both the oxidation and alkylation reaction reveals a potential method for the valorization of lignocellulosic biomass.
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Keglevich, György, Nóra Zs Kiss, and Zoltán Mucsi. "Milestones in microwave-assisted organophosphorus chemistry." Pure and Applied Chemistry 88, no. 10-11 (November 1, 2016): 931–39. http://dx.doi.org/10.1515/pac-2016-0604.
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AbstractOur recent results in the field of microwave (MW)-assisted organophosphorus syntheses, especially regarding esterifications, condensations, substitutions and additions are surveyed. Beside making organic chemical reactions more efficient, it was possible to perform transformations that are reluctant on conventional heating. Another option is to substitute catalysts, or to simplify catalyst systems under MW conditions. It is also the purpose of this paper to elucidate the scope and limitations of the MW tool, to interpret the MW effects, and to model the distribution of the local overheatings and their beneficial effect. All these considerations are possible on the basis of the enthalpy of activations determined by us utilizing the Arrhenius equation and the pseudo first order kinetic equation.
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Ivanovich, Zvegintsev Valery, Nalivaichenko Denis Gennadievich, and Chirkashenko Vladimir Fedorovich. "Investigation of the Pulsed Annular Gas Jet for Chemical Reactor Cleaning." International Journal of Chemical Engineering 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/517465.
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The most economical technology for production of titanium dioxide pigment is plasma-chemical syntheses with the heating of the oxygen. The highlight of the given reaction is formation of a solid phase as a result of interactions between two gases, thus brings the formation of particle deposits on the reactor walls, and to disturbing the normal operation of the technological process. For the solving of the task of reactor internal walls cleaning the pulsed gaseous system was suggested and investigated, which throws circular oxygen jet along surfaces through regular intervals. Study of aerodynamic efficiency of the impulse system was carried by numerical modeling and experimentally with the help of a specially created experimental facility. The distribution of the pulsed flow velocity at the exit of cylindrical reactor was measured. The experimental results have shown that used impulse device creates a pulsed jet with high value of the specified flow rate. It allows to get high velocities that are sufficient for the particle deposits destruction and their removal away. Designed pulsed peelings system has shown high efficiency and reliability in functioning that allows us to recommend it for wide spreading in chemical industry.
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Andraos, John. "Aiming for a standardized protocol for preparing a process green synthesis report and for ranking multiple synthesis plans to a common target product." Green Processing and Synthesis 8, no. 1 (January 28, 2019): 787–801. http://dx.doi.org/10.1515/gps-2019-0048.
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Abstract This paper proposes a standardized format for the preparation of process green synthesis reports that can be applied to chemical syntheses of active pharmaceutical ingredients (APIs) of importance to the pharmaceutical industry. Such a report is comprised of the following eight sections: a synthesis scheme, a synthesis tree, radial pentagons and step E-factor breakdowns for each reaction step, a tabular summary of key material efficiency step and overall metrics for a synthesis plan, a mass process block diagram, an energy consumption audit based on heating and cooling reaction and auxiliary solvents, a summary of environmental and safety-hazard impacts based on organic solvent consumption using the Rowan solvent greenness index, and a cycle time process schedule. Illustrative examples of process green synthesis reports are given for the following pharmaceuticals: 5-HT2B and 5-HT7 receptors antagonist (Astellas Pharma), brivanib (Bristol-Myers Squibb), and orexin receptor agonist (Merck). Methods of ranking synthesis plans to a common target product are also discussed using 6 industrial synthesis plans of apixaban (Bristol-Myers Squibb) as a working example. The Borda count method is suggested as a facile and reliable computational method for ranking multiple synthesis plans to a common target product using the following 4 attributes obtained from a process green synthesis report: process mass intensity, mass of sacrificial reagents used per kg of product, input enthalpic energy for solvents, and Rowan solvent greenness index for organic solvents.
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Popova, Larisa Mikhaylovna, Varvara Alekseyevna Ivanova, and Sergey Vyacheslavovich Vershilov. "SYNTHESES OF POLYFLUOROALKYL ESTERS OF MALEOPIMARIC ACID N-PHENYLIMIDE." chemistry of plant raw material, no. 2 (January 12, 2019): 205–11. http://dx.doi.org/10.14258/jcprm.2019023999.
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To meet the challenge of complex processing of plant material, in particular, tall oil rosin, research has been conducted on the synthesis of new polyfluroalkyl maleimides. As is well known, maleopimaric acid’s imides constitute a forward-looking class of organic compounds for pharmacology, agriculture, polymer chemistry and so on. The introduction of a fluorocarbon unit often gives high surface activity, chemical and heat resistance, hydrophobic and oleophobic properties. This paper presents the results of experiments on the synthesis of new N-phenylimides of maleopimaric acid’s polyfluoroalkyl esters by the interaction of the corresponding monosubstituted polyfluorinated maleopimarates with aniline during boiling for 10–16 h in toluene (40–52%). The starting N-phenylimide of maleopimaric acid has been obtained by two methods: by the Diels-Alder reaction from abietic acid and N-phenyl maleimide using sulfuric acid as a catalyst in the melt (40%) and by heating (MPA) with aniline in toluene (80%). 2,2,3,3,4,4,5,5-octafluoroamyl and 2,2,3,3,4,4,5,5,6,6,7,7,7- dodecaftaforpetyl ethers have been obtained by esterification of MPA with fluorinated alcohols under conditions of acid catalysis (70%). It have been identified the ester bonds are quite stable by TLC during long-term treatment of the stock (over 11 hours). The synthesized substances were analyzed with UV-, IR-, 1H NMR and 19F.
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Charvot, Jaroslav, Daniel Pokorný, Milan Klikar, Veronika Jelínková, and Filip Bureš. "Towards Volatile Organoselenium Compounds with Cost-Effective Synthesis." Molecules 25, no. 21 (November 9, 2020): 5212. http://dx.doi.org/10.3390/molecules25215212.
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The current portfolio of organoselenium compounds applicable as volatile precursors for atomic layer deposition can be denoted as very limited. Hence, we report herein facile and cost-effective preparation of two bis(trialkylstannyl)selenides as well as one selenole and three bis(trialkylsilyl)selenides. Their syntheses have been optimized to: (i) use readily available and inexpensive starting materials, (ii) involve operationally simple methodology (heating in a pressure vessel), (iii) use a minimum amount of additives and catalysts, and (iv) either exclude additional purification or involve only simple distillation. The chemical structure of prepared Se derivatives was confirmed by multinuclear NMR and GC/MS. Their fundamental thermal properties were investigated by differential scanning calorimetry (DSC) and TGA methods that revealed thermal stability within the range of 160–300 °C.
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Dudina, Dina V., and Amiya K. Mukherjee. "Reactive Spark Plasma Sintering: Successes and Challenges of Nanomaterial Synthesis." Journal of Nanomaterials 2013 (2013): 1–12. http://dx.doi.org/10.1155/2013/625218.
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Spark plasma sintering (SPS), initially developed as an advanced sintering technique for consolidating nanopowders into nanostructured bulk materials, has been recently looked at in much broader perspective and gained a strong reputation of a versatile method of solid state processing of metals, ceramics, and composites. The powders in the SPS-dies experience the action of pulsed electric current and uniaxial pressure; they are heated at very high rates unachievable in furnace heating and sintered within shorter times and at lower temperatures than in conventional methods. The principle of SPS and convenient design of the facilities make it attractive for conducting solid state synthesis. In this paper, based on our own results and the literature data, we analyze the microstructure formation of the products of chemical reactions occurring in the SPS in an attempt to formulate the requirements to the microstructure parameters of reactant mixtures and SPS conditions that should be fulfilled in order to produce a nanostructured material. We present successful syntheses of nanostructured ceramics and metal matrix composite with nanosized reinforcements in terms of microstructure stability and attractive properties of the materials and discuss the challenges of making a dense nanostructured material when reaction and densification do not coincide during the SPS. In the final part of the paper, we provide an outlook on the further uses of reactive SPS in the synthesis of nanostructured materials.
Dissertations / Theses on the topic "Heating; Chemical syntheses"
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Whittaker, Andrew Gavin. "Some chemical properties of microwave radiation." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259845.
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Liao, Xiangjun 1970. "Dielectric properties and their application in microwave-assisted organic chemical reactions." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=38220.
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This study was designed to develop some predictive models for the dielectric properties of the chemicals and chemical reactions and make use of dielectric properties and microwave irradiation in the chemical reactions. Specifically, the dielectric properties of the following systems were investigated at microwave frequencies of 2450 and 915 MHz: (1) C1--C5 alcohols, (2) glucose aqueous solutions, (3) lysine aqueous solutions, (4) mimicked esterification reaction model systems of parahydroxybenzoic acid with methanol, 1-propanol and 1-butanol in the presence of para-toluene sulfonic acid as a catalyst, (5) Maillard reaction model system consisting of glucose, lysine and water.The dielectric properties of the model systems showed that they depended on the frequency applied, concentration of the material, and temperature. Most of the predictive models showed that there exists a linear or quadratic relationship between dielectric constant and concentration or temperature. However, the quadratic equation is better than the linear one to describe the variation of the loss factor with temperature or concentration.
Esterification showed great advantages for the use of microwave irradiation in chemical reaction. It included reduction in reaction time, and provided distinct temperature profiles due to microwave environment during chemical reactions. The reason for rate enhancement of this type of reaction was also demonstrated from the temperature profile.
Microwave-assisted solvent free Maillard reaction model system, consisting of glucose and lysine, demonstrated that the heating method applied was not one of the crucial factors, but the temperature level was important during the chemical reaction.
The relationship of loss factor with yield of reaction showed that it is possible to use dielectric data to analyze, and monitor the chemical reaction. It provided a new methodology to analyze the reaction.
The relationship between the loss factor, loss tangent and the reaction time, and concentration of the material showed that it is also possible to use dielectric data at microwave frequencies of 2450 and 915 MHz to study chemical reactions, especially the kinetics.
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Chaplain, Grant Thomas Robert. "Development of a continuous flow microreactor for chemical synthesis with in-line catalysis, heating and detection." Thesis, University of Hull, 2013. http://hydra.hull.ac.uk/resources/hull:8445.
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The development of a micro fluidic flow organic synthetic system incorporating heterogeneous catalysis, novel heating regimes and in-line spectroscopic detection is described. The reactions used to model the flow synthesis include Suzuki and acetylation reactions using heterogeneous immobilised palladium and tungstosilicic acid catalyst respectively. Catalyst immobilisation was carried out on silica monoliths made using Tetraethyl orthasilicate (TEOS) as a precursor which produced surface areas of 240 ±9 m² g¯¹ and porosities between 0.65 and 0.70 with nano pore diameters of 1100 ±20 nm. Functionalisation of the TEOS monoliths with palladium was achieved through the formation of palladium nano clusters within the nano pores of the monolith. Once immobilised, the palladium bound monolith was placed into a flow stream as a capillary monolithic reactor (CMR). Microwave and conventional oven heating were applied to the catalyst as the reactants 4-bromobenzonitrile and phenyl boronic acid to produce 4-cyanobiphenyl flowed through with different residence times and temperatures. Under microwave heating, the monolithic structure and the tube connections present in the microwave were observed to break down, an effect thought to be associated with very high localised heating of the palladium. Heating however using convection from a column heater proved to be more successful and facilitated the continuous flow of reactants without flow disruption. In-line Raman spectroscopy was placed in to the flow system as a detection method replacing off-line gas chromatography-mass spectrometry (GC-MS). Calibration using Raman spectra was achieved using partial least square regression (PLSR) which gave results within ±10% to those obtained using the GC-MS method. Using the flow system with in-line Raman analysis, the reaction was optimised and kinetic studies were performed. For the reaction conditions used, the overall 2nd order rate constant k was 4.45 x 10¯³ M¯¹ s¯¹, and the optimal flow rate for 4-cyanobiphenyl production was 0.30 mL min¯¹ producing 53 g h¯¹ (with a 14% conversion). The optimal conversion under the flow parameters performed was at 0.02 mL min¯¹ showing 61% conversion (producing 17 g h¯¹). The reaction was then altered to accommodate an acetylation reaction. Tungstosilicic acid was immobilised on the surface of TEOS monoliths and the CMRs were actively catalysing the reaction between 4-bromophenol and acetic anhydride to produce 4-bromophenyl acetate. Unfortunately, leaching of the tungstosilicic acid was observed from the monolith surface which interfered with Raman spectroscopic observations making detection of reactants and products difficult. In conclusion the overall project was a successful venture. It allowed fast optimisation procedures for reaction scaling, and produced a significant amount of molecular data for each reaction ran. This model set-up was appropriate and versatile for the objectives of this project. Areas within the research to address were improving the catalyst immobilisation techniques, and different heating mechanisms. Despite this, the flow reaction system was an advance towards developing a fully automated flow synthetic optimisation system.
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Bondi, Scott Nicholas. "LCVD synthesis of carbon nanotubes and their characterization." Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-08112004-143541/unrestricted/bondi%5Fscott%5Fn%5F200412%5Fphd.pdf.
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Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2005.Z.L. Wang, Committee Member ; Thomas Starr, Committee Member ; Mostafa Ghiaasiaan, Committee Member ; W. Jack Lackey, Committee Chair; Shreyes Melkote, Committee Member. Vita. Includes bibliographical references.
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Garcia, Soto Mariano de Jesús. "Synthesis of Gold Nanostructures with Optical Properties within the Near-Infrared Window for Biomedical Applications." Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/321533.
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The work reported in this dissertation describes the design and synthesis of different gold nanoshells with strong absorption coefficients at the near-infrared region (NIR) of the spectrum, and includes preliminary studies of their use for the photo-induced heating of pancreatic cancer cells and ex vivo tissues. As the emphasis was on gold nanoshells with maximum extinctions located at 800 nm, the methods explored for their synthesis led us to the preparation of silica-core and hollow gold nanoshells of improved stability, with maximum extinctions at or beyond the targeted within the near-infrared window. The synthesis of silica-core gold nanoshells was investigated first given its relevance as one of the pioneering methods to produce gold nanostructures with strong absorption and scattering coefficients in the visible and the near-infrared regions of the spectrum. By using a classical method of synthesis, we explored the aging of the precursor materials and the effect of using higher concentrations than the customary for the reduction of gold during the shell growth. We found that the aging for one week of the as-prepared or purified precursors, namely, the gold cluster suspensions, and the seeded silica particles, along with higher concentrations of gold in the plating solution, produced fully coated nanoshells of 120 nm in size with smooth surfaces and maximum extinctions around 800 nm. Additional work carried out to reduce the time and steps in the synthesis of silica-core gold nanoshells, led us to improve the seeding step by increasing the ionic strength of the cluster suspension, and also to explore the growth of gold on tin-seeded silica nanoparticles. The synthesis of hollow gold nanoshells (HGS) of with maximum extinctions at the NIR via the galvanic replacement of silver nanoparticles for gold in solution was explored next. A first method explored led us to obtain HGS with maximum extinctions between 650 and 800 nm and sizes between 30 and 80 nm from silver nanoparticles, which were grown by the addition of silver nitrate and a mild reducer. We developed a second method that led us to obtain HGS with maximum extinctions between 750 and 950 nm by adjusting the pH of the precursor solution of the silver particles without much effort or additional steps. The last part of this work consisted in demonstrating the photo-induced heating of two biological systems containing HGS. Photothermal therapy studies of immobilized PANC1 pancreas cancer cells in well-plates were carried out with functionalized HGS. We found that cells exposed to HGS remained viable after incubation. Moreover, the cells incubated with HGS modified with mercaptoundecanoic acid and folic acid turned non-viable after being irradiated with a laser at 800 nm. The other study consisted in the laser-induced heating between 750 and 1000 nm of ex vivo tissues of chicken and pork with nanoshells injected. In comparison with non-injected tissues, it was found that the temperature at the irradiated areas with HGS increased more than 10 °C. Moreover, the extent of the heated area was broader when the laser was used at wavelengths beyond 900 nm, suggesting that the heating was due to the radiation absorbed and transformed into heat primarily by the HGS and at a lesser extent by the water in the tissue.
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Moura, Jorge Pedro Amaral Duarte de. "Development of an inductive heating system for the graphene synthesis by cold wall CVD." Master's thesis, 2019. http://hdl.handle.net/10773/27754.
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Since it was firstly isolated, graphene has become one of the most researched nano materials, due to its exciting physical and chemical properties, namely the nearly ballistic transport and high charge mobility, optical transparency and extreme mechanical behaviour, meeting a
plethora of application fields. However, the industrial mass-production is still to overcome, and a multitude of growing processes evolved as an effort to reach this objective. Fast, controlled and scalable growth of single crystalline graphene in a continuous process are the basic
guidelines for an ideal synthesis process, that the Chemical Vapour Deposition (CVD) technique can offer.
This work settles on the exploitation of Cold Wall CVD by designing, developing and testing an electromagnetic inductively assisted CVD system. This approach proved to enable rapid and controlled heating curves, allowing for sample suspension inside the reactor tube, permitting an operation based on optical pyrometric monitoring of the temperature as a key parameter for the growth process. Using this system, high quality single layer graphene domains with well-defined hexagonal shape were obtained, as confirmed by Raman spectroscopy and scanning electron microscopy. The present work contributes with an effort towards an understanding of graphene growth mechanisms in order to accurately control the substrate temperature, a key growth parameter.Desde que foi isolado pela primeira vez, o grafeno assumiu-se como um dos nano-materiais mais investigados dadas as suas extraordinárias propriedades, nomeadamente a condução elétrica quase balística e elevada mobilidade de carga, transparência ótica e comportamento mecânico extremo, compatíveis com um sem número de campos de aplicação. No entanto, a sua produção industrial em larga escala ainda não foi alcançada, e vários métodos de síntese foram sendo desenvolvidos num esforço para atingir esse objetivo. A síntese rápida, controlada e escalável num processo contínuo de grafeno monocristalino são condições altamente desejáveis que a técnica de Deposição Química em Fase de Vapor oferece. Este trabalho baseia-se no desenvolvimento de um sistema de aquecimento indutivo para a síntese de grafeno num reator CVD de parede fria, englobando a sua conceção, construção e validação. Esta abordagem permitiu obter curvas de aquecimento rápidas e controladas, numa configuração de amostra suspensa, possibilitando uma operação baseada na monitorização pirométrica da temperatura como parâmetro chave para o processo de crescimento. Utilizando este equipamento, foi possível obter domínios hexagonais de grafeno de camada única e elevada qualidade, como confirmado por espectroscopia de Raman e microscopia eletrónica de varrimento. O presente trabalho contribui para a compreensão dos mecanismos de crescimento de grafeno através do controlo preciso da temperatura do substrato, identificado como um parâmetro chave.
Trabalho desenvolvido no âmbito do projeto UID/CTM/50015/2019 financiado por fundos nacionais pela FCT/MEC (UID/CTM/50025/2019) e cofinanciado pelo FEDER(POCI-01-0145-FEDER028755) sob o acordo de parceria PT2020.
Mestrado em Engenharia Física
Books on the topic "Heating; Chemical syntheses"
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Microwave-assisted organic synthesis: A green chemical approach. Oakville, ON: Apple Academic Press Inc., 2015.
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Naplocha, Krzysztof. Materiały kompozytowe umacniane preformami wytworzonymi w procesie wysokotemperaturowej syntezy w polu mikorfalowym: Composite materials reinforced with preforms manufactured by high temperature synthesis in microwave field. Wrocław: Oficyna Wydawnicza Politechniki Wrocławskiej, 2013.
Find full textBook chapters on the topic "Heating; Chemical syntheses"
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Jha, Anjali. "Microwave Assisted Synthesis of Organic Compounds and Nanomaterials." In Nanofibers - Synthesis, Properties and Applications. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.98224.
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In the Conventional laboratory or industry heating technique involve Bunsen burner, heating mental/hot plates and electric heating ovens. To produce a variety of useful compounds for betterment of mankind, the Microwave Chemistry was introduced in year 1955 and finds a place in one of the Green chemistry method. In Microwave chemistry is the science of applying microwave radiation to chemical reactions. Microwaves act as high frequency electric fields and will generally heat any material containing mobile electric charges, such as polar molecules in a solvent or conducting ions in a solid. Polar solvents are heated as their component molecules are forced to rotate with the field and lose energy in collisions i.e. the dipole moments of molecules are important in order to proceed with the chemical reactions in this method. It can be termed as microwave-assisted organic synthesis (MAOS), Microwave-Enhanced Chemistry (MEC) or Microwave-organic Reaction Enhancement synthesis (MORE). Microwave-Assisted Syntheses is a promising area of modern Green Chemistry could be adopted to save the earth.
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Predoana, Luminita, Dániel Attila Karajz, Vincent Otieno Odhiambo, Irina Stanciu, Imre M. Szilágyi, György Pokol, and Maria Zaharescu. "Influence of the Microwaves on the Sol-Gel Syntheses and on the Properties of the Resulting Oxide Nanostructures." In Microwave Heating [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.94931.
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Among the chemical methods in the liquid phase, the sol–gel technique is a versatile and efficient method for pure or doped metal oxide films or powders preparation, showing some advantages over other preparation techniques (high homogeneity, the possibility to introducing dopants in large amount, low processing temperature and control over the stoichiometry). Combining the sol–gel (SG)method with the effect of ultrasounds(US) or microwaves (MW) leads to improving the sol–gel procedure. The microwave-assisted sol–gel method is most frequently used for obtaining nanocrystalline, monodispersed oxide nanoparticles, or to transform amorphous gels into well-crystallized nanopowders. Less studied is the influence of the microwaves on the sol–gel reactions in solutions. The benefit of using microwave-assisted sol–gel preparation highly depends on the reagents used and on the composition of the studied systems. In the present chapter, results on the influence of the microwaves on the chemical reactions that take place during the sol–gel synthesis and on the properties of the resulted samples are discussed.
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Predoanǎ, Luminita, Dániel Attila Karajz, Vincent Otieno Odhiambo, Irina Stanciu, Imre M. Szilágyi, György Pokol, and Maria Zaharescu. "Influence of the Microwaves on the Sol-Gel Syntheses and on the Properties of the Resulting Oxide Nanostructures." In Microwave Heating - Electromagnetic Fields Causing Thermal and Non-Thermal Effects. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.94931.
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Among the chemical methods in the liquid phase, the sol–gel technique is a versatile and efficient method for pure or doped metal oxide films or powders preparation, showing some advantages over other preparation techniques (high homogeneity, the possibility to introducing dopants in large amount, low processing temperature and control over the stoichiometry). Combining the sol–gel (SG)method with the effect of ultrasounds(US) or microwaves (MW) leads to improving the sol–gel procedure. The microwave-assisted sol–gel method is most frequently used for obtaining nanocrystalline, monodispersed oxide nanoparticles, or to transform amorphous gels into well-crystallized nanopowders. Less studied is the influence of the microwaves on the sol–gel reactions in solutions. The benefit of using microwave-assisted sol–gel preparation highly depends on the reagents used and on the composition of the studied systems. In the present chapter, results on the influence of the microwaves on the chemical reactions that take place during the sol–gel synthesis and on the properties of the resulted samples are discussed.
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Saleh, Tawfik A., Shafquat Majeed, Arunima Nayak, and Brij Bhushan. "Principles and Advantages of Microwave-Assisted Methods for the Synthesis of Nanomaterials for Water Purification." In Research Anthology on Synthesis, Characterization, and Applications of Nanomaterials, 426–39. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-8591-7.ch020.
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Nanomaterials are the pillars of nanoscience and nanotechnology and to realize their full potential in various potential applications, synthetic methodologies/routes need to be established that are simple, fast and cost-effective. Wet-chemical approaches for nanomaterial synthesis have proven to be among the most versatile and effective routes to finely tailor nanocrystals with varying compositional and architectural complexity. Microwave-assisted solution route represents an efficient wet-chemical approach for the synthesis of nanomaterials that offers additional advantages, such as rapid volumetric heating, high reaction rates, size and shape control by tuning reaction parameters, and energy efficiency. In addition, the homogenous heating of the reactants in microwave synthesis minimizes thermal gradients and provides uniform nucleation and growth conditions that leads to the formation of nanomaterials with uniform size distribution. This chapter deals with the basics of microwave chemistry and its applications towards the synthesis of nanomaterials for catalytic applications.
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Taber, Douglass. "Best Synthetic Methods: Functional Group Transformation." In Organic Synthesis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199764549.003.0007.
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François Morvan of the Université de Montpellier, using the inexpensive dimethyl phosphite, optimized (Tetrahedron Lett. 2008, 49, 3288) the free radical reduction of 1 to 2. Pawan K. Sharma of Kurukshetra University found (Tetrahedron Lett. 2008, 48, 8704) that NaBH4 in the presence of a catalytic amount of RuCl3.xH2 O reduced monosubstituted and disubstituted alkenes, such as 3, to the corresponding alkanes. Note that benzyl ethers were stable to these conditions. Ken Suzuki of Asahi Kasei Chemicals and Shun-Ichi Murahashi of Okayama University of Science established conditions (Angew. Chem. Int. Ed. 2008, 47, 2079) for the oxidation of primary amines such as 5 to oximes. Both ketoximes such as 6 and aldoximes were prepared using this protocol. Primary and secondary alcohols were stable to these conditions. Three noteworthy procedures for the oxidation of an aldehyde to the acid oxidation state were recently reported. Jonathan M. J. Williams of the University of Bath demonstrated (Chem. Commun. 2008, 624) that crotonitrile could serve as the hydrogen acceptor in the oxidation of an aldehyde 7 to the methyl ester 8. Note that isolated alkenes were stable to these conditions. Vikas N. Telvekar the University Institute of Chemical Technology, Mumbai improved (Tetrahedron Lett . 2008, 49, 2213) the oxidative amination of an aldehyde 9 to the nitrile 10. G. Sekar of the Indian Institute of Technology Madras effected (Tetrahedron Lett. 2008, 49, 1083) oxidation of an aldehyde 11 to the acid 12, under conditions that would be expected to not oxidize a primary or secondary alcohol. J. S. Yadav of the Indian Institute of Chemical Technology, Hyderabad observed (Tetrahedron Lett. 2008, 49, 3015) that the activation of a thiophenol 14 with N-chlorosuccimide generated a species that added regioselectively to a ketone 13 to give the thioether 15. Oxidation of the sulfide 15 followed by heating of the resulting sulfoxide would give the enone 16. This appears to be an easily scalable procedure. It is well known that an acid 17 and an amine 18 will condense at elevated temperature to give the amide 20.
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Marganakop, Sheetal, Pramod Kattimani, Sudha Belgur Satyanarayana, and Ravindra Kamble. "Microwave Synthesized Functional Dyes." In Microwave Heating - Electromagnetic Fields Causing Thermal and Non-Thermal Effects. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.94946.
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Microwave chemistry involves the application of microwave radiation to chemical reactions and has played an important role in organic synthesis. Functional dyes are those with hi-tech applications and this chapter attempts to provide an overview of the recent developments in microwave-assisted synthesis of functional dyes. Emphasis has been paid to the microwave-assisted synthesis of dye molecules which are useful in hi-tech applications such as optoelectronics (dye-sensitized solar cells), photochromic materials, liquid crystal displays, newer emissive displays (organic-light emitting devices), electronic materials (organic semiconductors), imaging technologies (electrophotography viz., photocopying and laser printing), biomedical applications (fluorescent sensors and anticancer treatment such as photodynamic therapy). In this chapter, the advantages of microwaves as a source of energy for heating synthesis reactions have been demonstrated. The use of microwaves to functional dyes is a paradigm shift in dye chemistry. Until recently most academic laboratories did not practice this technique in the synthesis of such functional dyes but many reports are being appeared in the journals of high repute.
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Taber, Douglass F. "Organic Functional Group Protection." In Organic Synthesis. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199965724.003.0012.
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Masato Kitamura of Nagoya University investigated (Chemistry Lett. 2009, 38, 188) the Ru-mediated deprotection of allyl ethers such as 1. The same catalyst was effective for the preparation of allyl ethers from the alcohol 2 and allyl alcohol. István E. Markó of the Université Catholique de Louvain showed (Organic Lett. 2009, 11, 2752) that SmI2 effected the reductive cleavage of an aryl ester 3, liberating the alcohol 4. Osamu Onomura of Nagasaki University found (Tetrahedron Lett. 2009, 50, 1466) that catalytic CuCl2 mediated the selective monoallylation of symmetrical diols such as 5. Péter Fügedi of the Hungarian Academy of Sciences, Budapest, observed (Tetrahedron Lett. 2009, 50, 2914) that TMSOTf catalyzed the selective reduction of 7 to the benzyl ether. BH3. NMe2 delivered the opposite regioisomer. Direct amination of an ester has been a long-sought transformation. Vladimir B. Birman of Washington University found (Organic Lett. 2009, 11, 1499) that 1,2,4-triazole 11 in combination with DBU was an effective catalyst for this reaction. Unactivated esters required higher reaction temperatures. Deprotection of amides often requires vigorous conditions, and the product free amines can be challenging to handle. Stefan G. Koenig of Sepracor Chemical Process devised (Organic Lett. 2009, 11, 433) a simple protocol for in situ formation and hydrolysis of the imidoyl chloride from 12 that delivered the amine hydrochloride 13 directly. Remarkably, benzamides are stable under these conditions. Hongmei Li of Merck Process devised (Tetrahedron Lett. 2009, 50, 1010) a related procedure: heating the more reactive trifluoroacetamide 14 with stoichiometric p-toluenesulfonic acid, and isolating the product as the p-toluenesulfonate salt 15. There has been a reluctance to use sulfonamide protecting groups, as they have been thought to be difficult to remove. Göran Hilmersson of the University of Gothenburg established (Organic Lett. 2009, 11, 503) that SmI2 instantaneously deprotected 16. Daniel E. Falvey of the University of Maryland designed (J. Org. Chem. 2009, 74, 3894) the benzyl ester 17, which was readily released under photolysis. Stanislaw Krompiec of the University of Silesia described (Tetrahedron Lett. 2009, 50, 1193) what appears to be a general strategy for the preparation of ortho esters such as 21.
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Taber, Douglass F. "Organocatalyzed C–C Ring Construction: The Bradshaw/Bonjoch Synthesis of (−)-Cermizine B." In Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0071.
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In a continuation of his studies (OHL20141229, OHL20140811) of organocatalyzed 2+2 photocycloaddition, Thorsten Bach of the Technische Universität München assembled (Angew. Chem. Int. Ed. 2014, 53, 7661) 3 by adding 2 to 1. Li-Xin Wang of the Chengdu Institute of Organic Chemistry also used (Org. Lett. 2014, 16, 6436) an organocatalyst to effect the addition of 5 to 4 to give 6. Shuichi Nakamura of the Nagoya Institute of Technology devised (Org. Lett. 2014, 16, 4452) an organocatalyst that mediated the enantioselective opening of the aziridine 7 to 8. Zhi Li of the National University of Singapore cloned (Chem. Commun. 2014, 50, 9729) an enzyme from Acinetobacter sp. RS1 that reduced 9 to 10. Gregory C. Fu of Caltech developed (Angew. Chem. Int. Ed. 2014, 53, 13183) a phosphine catalyst that directed the addition of 12 to 11 to give 13. Armido Studer of the Westfälische Wilhelms-Universität Münster showed (Angew. Chem. Int. Ed. 2014, 53, 9622) that 15 could be added to 14 to give 16 in high ee. Akkattu T. Biju of CSIR-National Chemical Laboratory described (Chem. Commun. 2014, 50, 14539) related results. The photostimulated enantioselective ketone alkylation developed (Chem. Sci. 2014, 5, 2438) by Paolo Melchiorre of ICIQ was powerful enough to enable the alkylation of 17 with 18 to give 19, overcoming the stereoelectronic preference for axial bond formation. David W. Lupton of Monash University established (J. Am. Chem. Soc. 2014, 136, 14397) the organocatalyzed transformation of the dienyl ester 20 to 21. James McNulty of McMaster University added (Angew. Chem. Int. Ed. 2014, 53, 8450) azido acetone 23 to 22 to give 24 in high ee. There are sixteen enantiomerically-pure diastereomers of the product 27. John C.-G. Zhao of the University of Texas at San Antonio showed (Angew. Chem. Int. Ed. 2014, 53, 7619) that with the proper choice of organocatalyst, with or without subsequent epimerization, it was possible to selectively prepare any one of eight of those diastereomers by the addition of 26 to 25. William P. Malachowski of Bryn Mawr College showed (Tetrahedron Lett. 2014, 55, 4616) that 28, readily prepared by a Birch reduction protocol, was converted by heating followed by exposure to catalytic Me3P to the angularly-substituted octalone 29.
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Enoki, Toshiaki, Morinobu Endo, and Masatsugu Suzuki. "Synthesis and Intercalation Chemistry." In Graphite Intercalation Compounds and Applications. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195128277.003.0004.
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Alkali metal GICs are the best known donor type GICs, since they are easily prepared and their brilliant gold color for stage-1 GICs has attracted scientists working in intercalation chemistry. They have therefore been targets of intensive and detailed studies of their solid-state properties on the basis of the employment of highly oriented pyrolytic graphite (HOPG). There are several intercalation methods, which are classified basically into vapor-phase reaction, reaction of the mixture of graphite and alkali metal, high pressure reaction, electrochemical reaction, and reaction in a solvent. Among these methods, vapor-phase intercalation reaction is the most popular. The two-zone method can easily give alkali metal GICs with well-defined single-stage phases. The vapor pressure of the alkali metal becomes high enough to obtain a satisfactory reaction rate for intercalation reaction in the temperature range 200-550°C, at which we can use a Pyrex glass tube as a reaction chamber. Figure 2.1 shows a typical two-zone method, where graphite and alkali metal are maintained at different temperatures, TG and TI, respectively, in a vacuum-sealed glass tube placed in a two-zone furnace. Changing TI controls the vapor pressure of the alkali metal. Figure 2.2 presents the conditions of intercalation reaction with potassium, where single-stage phase samples with stages 1 to 8 are obtained by changing the temperature difference TG — TK (Nishitani et al., 1983). Typical experimental conditions are given in Table 2.1 for the preparation of K, Rb, and Cs GICs (Dresselhaus and Dresselhaus, 1981). The intercalation reaction is again carried out by heating a mixture of graphite and alkali metal in a vacuum-sealed glass tube. In this case, the reaction becomes considerably more rapid owing to direct contact of molten alkali metal with graphite, although the reaction takes place in a similar manner to the vapor-phase reaction. A stainless steel tube is used for the intercalation of lithium since lithium vapor degrades a glass tube because of its high chemical activity. Alkali metal can be intercalated into graphite when the alkali metal is solvated in liquid ammonia or an organic solvent such as dimethylsulphoxide (DMSO).
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"Wet-Chemical Synthesis Techniques for Colloidal Plasmonic Nanostructures Assisted by Convective or Microwave Dielectric Heating." In Handbook of Molecular Plasmonics, 413–82. Jenny Stanford Publishing, 2013. http://dx.doi.org/10.1201/b15328-15.
Full textConference papers on the topic "Heating; Chemical syntheses"
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Kang, Ki Moon, Hyo-Won Kim, Il-Wun Shim, and Ho-Young Kwak. "Syntheses of Specialty Nanomaterials at the Multibubble Sonoluminescence Condition." In ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-68320.
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In recent years, a large number of nano-size semiconductors have been investigated for their potential applications in photovoltaic cells, optical sensor devices, and photocatalysts [1, 2, 3]. Nano-size semiconductor particles have many interesting properties due mainly to their size-dependent electronic and optical properties. Appropriately, many speciality of nanomaterials such as CdS and ZnS semiconductor particles, and other metal oxides such as ZnO and lithium-titanate oxide (LTO) have been prepared. However, most of them were prepared with toxic reactants and/or complex multistep reaction processes. Particularly, it is quite difficult to produce LTO nanoparticles, since it typically requires wearisome conditions such as very high temperature over 1000 °C, long producing times, and so on. To overcome such problems, various core/shell type nanocrystals were prepared through different methods such as the hydrothermal synthetic method, microwave, and sonochemistry. Also many coating methods on inorganic oxide nanoparticles were tried for the preparations of various core-shell type nanocrystals. Sonoluminescence (SL) is a light emission phenomenon associated with the catastrophic collapse of a gas bubble oscillating under an ultrasonic field [4]. Light emission of single bubble sonoluminescence (SBSL) is characterized by picosecond flashes of the broad band spectrum extending to the ultraviolet [5, 6]. The bubble wall acceleration has been found to exceed 1011 g at the moment of bubble collapse. Recently observed results of the peak temperature and pressure from the sonoluminescing gas bubble in sulfuric acid solutions [9] were accurately predicted by the hydrodynamic theory for sonoluminescence phenomena [7, 10, 11, 12], which provides a clue for understanding sonochemical reactions inside the bubble and liquid layer adjacent to the bubble wall. Sonochemistry involves an application of sonoluminescence. The intense local heating and high pressure inside the bubbles and liquid adjacent bubble wall from such collapse can give rise to unusual effects in chemical reactions. The estimated temperature and pressure in the liquid zone around the collapsing bubble with equilibrium radius 5 μm, an average radius of bubbles generated in a sonochemical reactor at a driving frequency of 20 kHz with an input power of 179 W, is about 1000 °C and 500 atm, respectively. At the proper condition, a lot of transient bubbles are generated and collapse synchronistically to emit blue light when high power ultrasound is applied to liquid, and it is called multibubble sonoluminescence (MBSL). Figure 1 shows an experimental apparatus for MBSL with a cylindrical quartz cell, into which a 5 mm diameter titanium horn (Misonix XL2020, USA) is inserted [13]. The MBSL facilitates the transient supercritical state [14].in the liquid layer where rapid chemical reactions can take place. In fact, methylene blue (MB), which is one of a number of typical textile dyestuffs, was degraded very fast at the MBSL condition while MB does not degrade under simple ultrasonic irradiation [13]. MBSL has been proven to be a useful technique to make novel materials with unusual properties. In our study, various metal oxides such as ZnO powder [15], used as a primary reinforcing filler for elastomer, homogeneous Li4Ti5O12 nanoparticles [16], used for electrode materials, and core/shell nanoparticles such as CdS coating on TiO2 nanoparticles [17] and ZnS coating on TiO2 nanoparticles [18], which are very likely to be useful for the development of inorganic dye-sensitized solar cells, were synthesized through a one pot reaction under the MBSL condition. Figure 2 shows the XRD pattern of ZnO nanoparticles synthesized from zinc acetate dehydrate (Zn(CH3CO2)2 · 2H2O, 99.999%, Aldrich) in various alcohol solutions with sodium hydroxide (NaOH, 99.99%, Aldrich) at the MBSL condition. The XRD patterns of all powers indicate hexagonal zincite. The XRD pattern for the ZnO nanoparticles synthesized is similar to the ZnO powder produced by a modified sol-gel process and subsequent heat treatment at about 600 °C [19] as shown in Fig.3. The average particle diameter of ZnO powder is about 7 nm. A simple sonochemical method for producing homogeneous LTO nanoparticles, as shown schematically in Fig. 4. First, LiOH and TiO2 nanoparticles were used to prepare LiOH-coated TiO2 nanoparticles as shown in Fig.5. Second, the resulting nanoparticles were thermally treated at 500 °C for 1 hour to prepare LTO nanoparticles. Figure 6 shows a high resolution transmission electron microscope image of LTO nanoparticles having an average grain size of 30–40 nm. All the nanoparticle synthesized are very pure in phase and quite homogeneous in their size and shape. Recently we succeeded in synthesizing a supported nickel catalyst such as Ni/Al2sO3, MgO/Al2O3 and LaAlO3, which turned out to be effective for methane decomposition [20]. Sonochemistry may provide a new way to more rapidly synthesize many specialty nanoparticles with less waste [21]. This clean technology enables the preparation of new materials such as colloids, amorphous particles [22], and various alloys.
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Horikoshi, Satoshi. "ELUCIDATION OF ELECTROMAGNETIC WAVE EFFECT AND OUTGOING OF FUTURE TREND IN MICROWAVE CHEMISTRY AND BIOLOGY." In Ampere 2019. Valencia: Universitat Politècnica de València, 2019. http://dx.doi.org/10.4995/ampere2019.2019.9783.
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The German chemist Theodor Grotthuss was the first to formulate the first law of photochemistry in 1817; he postulated that a reaction could be driven by light when the energy of light is absorbed by molecules [1]. After that, photochemistry has greatly contributed to the development of photography. In addition, second laws of photochemistry (Stark-Einstein law) was enacted, and these two laws have elevated photochemistry as an academic (science) discipline over the last one hundred years. In addition, because of advances in light sources and various devices (engineering), such materials and processes as photocatalysts, organic solar cells, photopolymerization, quantum dots, and photochromism (among others) are currently being applied in various other fields. The next significant surge in chemistry is microwave chemistry wherein microwaves, which represent electromagnetic waves other than light, were introduced as a driving force in the chemical reaction domain in the late 1980s. There are three characteristics in this chemistry when using microwaves. The first is the high heating efficiency caused by the energy of the microwaves that directly reach and are absorbed by the substance. The second is the selectivity with which a specific substrate is heated, while the third characteristic is the enhancement of chemical syntheses by the microwaves’ electromagnetic wave energy, often referred to as the microwave effect (or non-thermal effect). The phenomenon of the microwave effect (third characteristic) impacting chemical reactions has been summarized in much of the relevant literature, however, the reason why the microwave effect has not been clarified to anyone’s satisfaction is that the term microwave effect in microwave chemistry includes numerous factors. In order to fix microwaves in the chemical field, it is urgent to develop laws of “microwavechemistry”, and to do it is necessary to systematization against the phenomenas of electromagnetic waves for materials and reactions. One of the reasons for the dramatic growth in photochemistry is the development of high power laser technology. In recent years, coherent semiconductor generator with the generating high power microwaves have become easy to get, so “microwavechemistry” can proceed to the next stage. We examined that the phenomena as microwave electromagnetic waves in chemical reactions by using a semiconductor generator and a power sensor. And, it clarified that the reaction rate and yield of a very small part of the chemical reaction change with the unique phenomenon to electromagnetic waves [2]. On the other hand, generally, as plants, enzymes, biological substances temperature rises, it inhibits growth and reaction. This phenomenon was used to overcome the electromagnetic wave effect. We have succeeded in improving these activities by irradiating weak microwaves which do not increase these temperatures [3]. If microwave heating is given to them, it will work negatively. In this invited presentation, it introduces the possibility of electromagnetic wave effect(s) in these and explain its industrial application.
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Sangl, J., C. Mayer, and T. Sattelmayer. "Dynamic Adaptation of Aerodynamic Flame Stabilization of a Premix Swirl Burner to Fuel Reactivity Using Fuel Momentum." In ASME Turbo Expo 2010: Power for Land, Sea, and Air. ASMEDC, 2010. http://dx.doi.org/10.1115/gt2010-22340.
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Due to the expected increase in available fuel gas variants in the future and the interest in independence from a specific fuel, fuel flexible combustion systems are required for future gas turbine applications. Changing the fuel used for lean premixed combustion can lead to serious reliability problems in gas turbine engines caused by the different physical and chemical properties of these gases. A new innovative approach to reach efficient, safe and low-emissions operation for fuels like natural gas, syntheses gas and hydrogen with the same burner is presented in this paper. The basic idea is to use the additionally available fuel momentum of highly reactive gases stemming from their lower Wobbe index (lower volumetric heating value and density) compared to lowly reactive fuels. Using fuel momentum opens the opportunity to influence the vortex dynamics of swirl burners designed for lowly reactive gases in a favorable way for proper flame stabilization of highly reactive fuels without changing the hardware geometry. The investigations presented in the paper cover the development of the optimum basic aerodynamics of the burner and the determination of the potential of the fuel momentum in water channel experiments using particle image velocimetry (PIV). The results show that a proper usage of the fuel momentum has enough potential to adjust the flow field to the different fuels and their corresponding flame behavior. As the main challenge is to reach flashback safe fuel flexible burner operation, the main focus of the study lies on avoiding combustion induced vortex breakdown (CIVB). The mixing quality of the resulting injection strategy is determined applying laser induced fluorescence (LIF) in water channel tests. Additional OH* chemiluminescence and flashback measurements in an atmospheric combustion test rig confirm the water channel results for CH4, CH4/H2 mixtures, H2 with N2 dilution and pure H2 combustion. They also indicate a large operating window between flashback and lean blow out and show expected NOx emission levels. In summary, it is shown for a conical four slot swirl generator geometry that the proposed concept of using the fuel momentum for tuning of the vortex dynamics allows aerodynamic flame stabilization for different fuels in the same burner.
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Tioni, Estevan, and Pascal Rousseaux. "BRINGING TOGETHER MICROWAVE ASSISTED SYNTHESIS AND CHEMICAL ENGINEERING PRINCIPLES." In Ampere 2019. Valencia: Universitat Politècnica de València, 2019. http://dx.doi.org/10.4995/ampere2019.2019.9901.
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It is nowadays admitted that microwaves are frequently used in organic chemistry labs [1] (even if not as much as it was predicted 20 years ago, one must say [2]). On the other side it is also certain that this technology has not yet found its place in chemical industry: application at a production scale are very scarce [3][4] and this despite the potential advantages of the technology (selective heating, high heating rate, low thermal inertia…). The point is that mastering all the aspects of microwaves assisted synthesis at industrial scale demands a lot of different skills to work together: chemistry, process engineering, microwave engineering, materials science. This is so challenging that tools and methodologies for quantification of industrial microwave interest and scaling-up of lab results are missing. In this work we present our contributions to the deployment of microwaves for synthesis in the chemical industry which are mainly The development of small pilot reactors (1 L) in stainless steel, capable to withstand temperature and pressureThe application of a chemical engineering methodology to microwave assisted synthesisAn example of intensification (see table) of an industrially interesting reaction using microwave to access NPW (high temperature and pressure)A tentative of rationalization of process criteria to identify a priori the interest of microwave heating for a specific application [1]. Diaz-Ortiz et al., Chem. Rec. 2019, 19, 85–97 [2]. Kappe, Chem. Rec. 2019, 19, 15–39 [3]. Aldivia, brevet WO2004/066683A1 [4]. https://cen.acs.org/articles/94/i36/Microwaving-ton.html
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Malewicz, Miroslaw, Michal Byrczek, and Helena Teterycz. "Synthesis of zinc oxide nanotiles by wet chemical route assisted by microwave heating." In 2009 32nd International Spring Seminar on Electronics Technology (ISSE). IEEE, 2009. http://dx.doi.org/10.1109/isse.2009.5206934.
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Hagiwara, Kenta, and Satoshi Horikoshi. "Rapid Synthesis of highly luminescent Carbon Quantum Dots using Low-Pressurized Microwave Solvothermal Heating." In Ampere 2019. Valencia: Universitat Politècnica de València, 2019. http://dx.doi.org/10.4995/ampere2019.2019.9784.
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Since the first serendipity of carbon quantum dots (CQDs)1, it is expected to be used for imaging materials for reusable living bodies (e.g. Hela cells). However, the reported CQDs synthetic methods have yet to be at the practical levels; the quantum yields is low, and synthetic condition is over 5 hrs under more than 30 atms. In this research, we ameliorated the problems of CQDs synthesis and luminescence (quantum yields) by the novel synthesis protocol using microwave chemistry. Specifically, we synthesized high quantum yields CQDs (61%) by utilizing a microwave chemical synthesis, synthesizing at low pressure condition (lower than 5 atom) and short reaction time (3 hrs). The achievement of this high quantum yields made it clear that the contribution of polyethylene glycol (PEG) shell to CQDs is large. It was confirmed from the DLS and TEM image that the particle size of the synthesized particles was 8 to 13 nm (Fig. 1). On the other hand, the relationship between the polymerization degree of added PEG and the quantum yields to the addition amount is summarized in Table 1. The quantum yields of CQDs without addition of PEG was 16.7 %, while it was improved at 61.1 % when 0.6 g of PEG6000 (Molecular weight: 6000) was added.We succeeded in remarkably improving the quantum yields by using PEG, which is usually used as a protective agent, as a shell. By using this method, we succeeded in improving the quantum yields of the existing report by approximately 3 times. From the surface modified structure of PEG, the mechanism of improvement of quantum yields will be considered.[1] X. Xu et al., J. Am. Chem. Soc., 2004, 126, 12736–12737.
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Jin, Yusuke, Keigo Kasuya, Keisuke Nagato, Hiroshi Morii, Takeshi Ooi, and Masayuki Nakao. "Local Synthesis of Single-walled Carbon Nanotubes on Zeolite-covered Silicon Substrate by Laser-heating Chemical Vapor Depositon." In 2007 2nd IEEE International Conference on Nano/Micro Engineered and Molecular Systems. IEEE, 2007. http://dx.doi.org/10.1109/nems.2007.352059.
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Takao, Yasumasa, Tsuyoshi Asai, Yasuhiro Shimada, Kiyotaka Shuzenji, and Takeshi Tachibana. "Development of Particulate Unit Operations and Morphology Property Relations of Particulate Products." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-41195.
Full textAbstract:
Some particulate unit operations (apparatus engineering) are developed to control the particle morphology. The innovative aspect of this operation is the correspondence between the necessary material properties and their apparatus optimization. Spherical powders of aluminum oxynitride and aluminum nitride are directly prepared by flame synthesis (in spite of the fact that oxygen serves as an indispensable reactant). Non-oxide powders are commonly non-spherical with a size below the submicrometer scale. The major limiting factors in their synthesis are free energy, reaction temperature, and reaction rate. The innovative aspect of this flame synthesis technology assisted by DC arc plasma concerns the reducing gas composition beyond 1500 K. A chemical equilibrium calculation indicates that the plasma heating compensates the lack of reaction temperature under a low oxygen condition. This burner realizes a high-speed reaction with the help of reactive species in the arcs. We also report the multilayer-coated cosmetic powders with regard to material application, and the powder bed shear force evaluation equipment with regard to apparatus optimization.
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Fiedor, Pawel, Joanna Ortyl, and Mariusz Galek. "MICROWAVE-ASSISTED SYNTHESIS AND SPECTROSCOPIC PROPERTIES OF NOVEL PYRIDINE-BASED FLUORESCENT MOLECULAR PROBES." In Ampere 2019. Valencia: Universitat Politècnica de València, 2019. http://dx.doi.org/10.4995/ampere2019.2019.9829.
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Fluorescent molecular probes become interesting analytical tools in determination and labeling of chemical compounds and physical properties such as viscosity and polarity. Currently known fluorescent molecular probes can selectively and regardless of the environment detect only few molecules, and applicability in determination of micro- viscosity and micro-polarity are limited to narrow range and specific condition, therefore design and synthesis of novel molecular probes with extended range of operation are highly needed [1]. Traditional synthesis of 2-amino-4,6-diphenyl-pyridine-3-carbonitrile’s requires two step reaction with long heating time or and toxic solvent. By application of microwave irradiation, reaction time can be firmly shortened with the same or higher efficiency [2]. Derivatives of 2-amino-4,6-diphenyl-pyridine-3-carbonitrile can find application in different fields of science. Depending on the structure of fluorophore, those compounds exhibit high sensitivity to changes in polarity and viscosity of environment, also concentration of specific cations, and pH can be determined by measuring of fluorescence spectrum.
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Fukushima, Jun, and Hirotsugu Takizawa. "IN-SITU SPECTROSCOPY AND TWO-COLOR THERMOGRAPHY DURING MICROWAVE IRRADIATION IN MATERIALS PROCESSING." In Ampere 2019. Valencia: Universitat Politècnica de València, 2019. http://dx.doi.org/10.4995/ampere2019.2019.9882.
Full textAbstract:
Concentration of microwave E-field between material particles is considered to cause the enhancement of sintering1 and chemical reaction under microwave irradiation. For example, it is usually required 1700 °C to synthesize AlN by carbothermal reduction method using Al2O3 as a starting material, but microwave processing can proceed this process at 1200 °C2. To understand this phenomenon, it is necessary to understand an occurrence behavior of plasma and a chemical reaction related to radical species generated by a local E-field concentration. In addition, in material synthesis using a raw material powder of several mm, it is suggested that a selective heating in the powder scale occurs. However, to discuss this selective heating behavior on this scale, it is necessary to realize a quantitative temperature measurement system with independent of the emissivity of the material and several mm spatial resolution. In this study, we conducted an in-situ spectroscopy and two-color thermography to verify these non-equilibrium effects during microwave irradiation. For example, in the iron making process, it was investigated that CN plasma was generated, and this CN radical contributed to the reduction reaction (Fig. 1(a))3. In addition, the developed two-dimensional two-color thermography system with a high resolution of 8.8 mm/pixel was enable to discuss local temperature gradients quantitatively (Fig. 1(b)).