Articles de revues : « Chemical reactions monitoring »

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Chen, Chun-Chi, et Po-Chiao Lin. « Monitoring of chemical transformations by mass spectrometry ». Analytical Methods 7, n^o 17 (2015) : 6947–59. http://dx.doi.org/10.1039/c5ay00496a.

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Swearer, Dayne F., Samuel Gottheim, Jay G. Simmons, Dane J. Phillips, Matthew J. Kale, Michael J. McClain, Phillip Christopher, Naomi J. Halas et Henry O. Everitt. « Monitoring Chemical Reactions with Terahertz Rotational Spectroscopy ». ACS Photonics 5, n^o 8 (18 mai 2018) : 3097–106. http://dx.doi.org/10.1021/acsphotonics.8b00342.

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Nielsen, Charles A., Ray W. Chrisman, Robert E. LaPointe et Theodore E. Miller. « Novel Tubing Microreactor for Monitoring Chemical Reactions ». Analytical Chemistry 74, n^o 13 (juillet 2002) : 3112–17. http://dx.doi.org/10.1021/ac020100i.

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Hsu, Chun-Yao, Gurpur Rakesh D. Prabhu et Pawel L. Urban. « Telechemistry 2.0 : Remote monitoring of fluorescent chemical reactions ». HardwareX 10 (octobre 2021) : e00244. http://dx.doi.org/10.1016/j.ohx.2021.e00244.

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Fleischer, Heidi, Vinh Quang Do et Kerstin Thurow. « Online Measurement System in Reaction Monitoring for Determination of Structural and Elemental Composition Using Mass Spectrometry ». SLAS TECHNOLOGY : Translating Life Sciences Innovation 24, n^o 3 (7 janvier 2019) : 330–41. http://dx.doi.org/10.1177/2472630318813838.

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The monitoring of chemical reactions is an important task in chemical engineering, especially in quality control, pharmaceutical and biological processes, or industrial production. The development of new reactions such as catalyst-based procedures requires detailed knowledge about process steps and reaction kinetics. For qualitative and quantitative analysis of reactants and resulting products, proprietary online measurement systems are used, which were designed for special applications. A mobile online reaction monitoring system was developed for a flexible coupling to different mass selective measurement systems for structural (ESI-MS) and elemental (ICP-MS) analysis to determine chemical precursors, reaction products, and internal standard compounds and their elemental composition at any stage of the reaction. Chemical reactions take place in a tempered continuous-flow microreactor. The flow rate in the microreactor can be varied to adjust the residence times in the reactor. An online dilution module was integrated to adapt the concentration of the reaction solutions to the working range of the analyzers. The performance and limitations of the online reaction system were determined using standard solutions and a real chemical reaction. The control software with a graphical user interface enables the adjustment of reaction, sampling, and measurement parameters as well as the system and process control.

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Čáchová, Monika, Lenka Scheinherrová, Libor Kobera, Martina Urbanová, Jiří Brus et Martin Keppert. « Monitoring of Kinetics of Pozzolanic Reaction ». Key Engineering Materials 722 (décembre 2016) : 126–31. http://dx.doi.org/10.4028/www.scientific.net/kem.722.126.

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The pozzolanic additions are widely used as concrete component for numerous technical, economic and environmental reasons. Obviously the hydration process in a pozzolana containing system differs from hydration of Ordinary Portland Cement (OPC) what is indicated macroscopically by slower increase of strength and lower hydration heat. This paper aims to study pozzolanic reaction from perspective of chemical kinetics. From this point of view pozzolanic reaction and carbonation are two parallel reactions which are competing for portlandite (Ca (OH)2). The rate of each of these two reactions is characterized by rate constant and order of reaction. The system under study was 1:1 mixture lime – ceramic powder. The course of reaction was primarily studied by thermogravimetry which results were further subjected to kinetic analysis. MAS NMR spectroscopy was used for study of structural changes taking place in material in the course of pozzolanic reaction.

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Jacquemmoz, Corentin, François Giraud et Jean-Nicolas Dumez. « Online reaction monitoring by single-scan 2D NMR under flow conditions ». Analyst 145, n^o 2 (2020) : 478–85. http://dx.doi.org/10.1039/c9an01758e.

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Stockinger, Skrollan, Julia Gmeiner, Kerstin Zawatzky, Johannes Troendlin et Oliver Trapp. « From stereodynamics to high-throughput screening of catalysed reactions ». Chem. Commun. 50, n^o 92 (2014) : 14301–9. http://dx.doi.org/10.1039/c4cc04892j.

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In this review we summarised recent developments in high-throughput kinetic monitoring of reactions including the dynamics of interconverting stereoisomers and the simultaneous combination of (catalysed) reactions with chemical analysis in on-column reaction chromatographic devices.

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Novotný, František, et Rostislav Lošot. « Chemical Reactions in a Soda-Lime Silicate Batch ». Advanced Materials Research 39-40 (avril 2008) : 459–64. http://dx.doi.org/10.4028/www.scientific.net/amr.39-40.459.

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Primary chemical reactions among the raw materials composing the batch give rise to various transitory intermediate products. Their physical properties influence the character of the glass melting process. The reaction pathway can be controlled by selecting the conditions, e.g. the grainsize composition of raw materials or the heating rate, which will influence the efficacy of the subsequent fining process. The present contribution describes practical technological properties of a couple of principal reaction pathways. A relationship between the practical monitoring of the actual glass melting process and the occurrence of peculiar chemical specimens is also mentioned.

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Bunker, Ian, Ridwan Tobi Ayinla et Kun Wang. « Single-Molecule Chemical Reactions Unveiled in Molecular Junctions ». Processes 10, n^o 12 (3 décembre 2022) : 2574. http://dx.doi.org/10.3390/pr10122574.

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Understanding chemical processes at the single-molecule scale represents the ultimate limit of analytical chemistry. Single-molecule detection techniques allow one to reveal the detailed dynamics and kinetics of a chemical reaction with unprecedented accuracy. It has also enabled the discoveries of new reaction pathways or intermediates/transition states that are inaccessible in conventional ensemble experiments, which is critical to elucidating their intrinsic mechanisms. Thanks to the rapid development of single-molecule junction (SMJ) techniques, detecting chemical reactions via monitoring the electrical current through single molecules has received an increasing amount of attention and has witnessed tremendous advances in recent years. Research efforts in this direction have opened a new route for probing chemical and physical processes with single-molecule precision. This review presents detailed advancements in probing single-molecule chemical reactions using SMJ techniques. We specifically highlight recent progress in investigating electric-field-driven reactions, reaction dynamics and kinetics, host–guest interactions, and redox reactions of different molecular systems. Finally, we discuss the potential of single-molecule detection using SMJs across various future applications.

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Hwang, Hyunsik, et Hyunjoon Song. « Nanoscale reaction monitoring using localized surface plasmon resonance scatterometry ». Chemical Physics Reviews 3, n^o 3 (septembre 2022) : 031301. http://dx.doi.org/10.1063/5.0090949.

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Heterogeneous reactions are highly dependent upon the local structure and environment of the catalyst surface within a nanoscale. Among numerous techniques for monitoring heterogeneous reactions, dark-field microscopy offers reliable data regardless of specific reaction conditions. In addition, plasmonic nanoprobes provide high sensitivity in a sub-wavelength resolution due to localized surface plasmon resonances susceptible to the dielectric change of objects and surroundings. By clever reaction cell design and data analysis, nanoparticle signals can be parallelly analyzed under variable reaction conditions in a controlled manner. This technique effectively measures the heterogeneity of individual nanoparticles for reaction monitoring. A wide range of chemical and electrochemical reactions have been monitored in situ and in operando at a single-particle level in this way. The advancement of localized surface plasmon scatterometry with simulation techniques approaches sub-particle accuracy in a high temporal resolution up to microseconds. Combining other in situ spectroscopic methods would make dark-field scatterometry a versatile tool for various reaction monitoring and sensing applications.

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Kashin, Alexey S., et Valentine P. Ananikov. « Monitoring chemical reactions in liquid media using electron microscopy ». Nature Reviews Chemistry 3, n^o 11 (26 septembre 2019) : 624–37. http://dx.doi.org/10.1038/s41570-019-0133-z.

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Blake, Steven, Thomas Mayer, Michael Mayer et Jerry Yang. « Monitoring Chemical Reactions by Using Ion-Channel-Forming Peptides ». ChemBioChem 7, n^o 3 (30 janvier 2006) : 433–35. http://dx.doi.org/10.1002/cbic.200500532.

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DE BONI, Luis Alcides Brandini. « EMPIRICAL / THEORETICAL PROPOSAL FOR THE PRODUCTION OF BIODIESEL ». Periódico Tchê Química 14, n^o 28 (20 août 2017) : 166–74. http://dx.doi.org/10.52571/ptq.v14.n28.2017.162_periodico28_pgs_166_174.pdf.

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The present manuscript represents the projection of laboratory experiments in a theoretical reactor projected for the production of biodiesel. The objectives of this project were: production of biodiesel in less time; to reduce the energy consumption into the production of biodiesel; Non-dependence of the reaction kinetics from the reaction's temperature and high conversion rates of raw material into the final product with transesterification reactions performed at stoichiometric limits. The results indicate that the use of a single reaction vessel to perform several stages of production without the transfer of the total mass of fuel fluid between several vessels reduces the total production time. The reaction time was also optimized with the use of an appropriate monitoring system. Performing the reactions near the stoichiometric limits reduced the refining time of the final product, as there are fewer raw materials to be removed from the final product. Monitoring of the reaction with real-time LASER spectroscopy allowed initiating the reaction at room temperature and increasing the supply of energy (heat) throughout the reaction, reducing the energy consumption during the reaction, and the moment of chemical balance was detected with the monitoring system.

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Gelinski, Estela Kamile, Fabiane Hamerski, Marcos Lúcio Corazza et Alexandre Ferreira Santos. « Biodiesel Synthesis Monitoring using Near Infrared Spectroscopy ». Open Chemical Engineering Journal 12, n^o 1 (14 novembre 2018) : 95–110. http://dx.doi.org/10.2174/1874123101812010095.

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Objective: Biodiesel is a renewable fuel considered as the main substitute for fossil fuels. Its industrial production is mainly made by the transesterification reaction. In most processes, information on the production of biodiesel is essentially done by off-line measurements. Methods: However, for the purpose of control, where online monitoring of biodiesel conversion is required, this is not a satisfactory approach. An alternative technique to the online quantification of conversion is the near infrared (NIR) spectroscopy, which is fast and accurate. In this work, models for biodiesel reactions monitoring using NIR spectroscopy were developed based on the ester content during alkali-catalyzed transesterification reaction between soybean oil and ethanol. Gas chromatography with flame ionization detection was employed as the reference method for quantification. FT-NIR spectra were acquired with a transflectance probe. The models were developed using Partial Least Squares (PLS) regression with synthetic samples at room temperature simulating reaction composition for different ethanol to oil molar ratios and conversions. Model predictions were then validated online for reactions performed with ethanol to oil molar ratios of 6 and 9 at 55ºC. Standard errors of prediction of external data were equal to 3.12%, hence close to the experimental error of the reference technique (2.78%), showing that even without using data from a monitored reaction to perform calibration, proper on-line predictions were provided during transesterification runs. Results: Additionally, it is shown that PLS models and NIR spectra of few samples can be combined to accurately predict the glycerol contents of the medium, making the NIR spectroscopy a powerful tool for biodiesel production monitoring.

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Wang, Wei. « Imaging the chemical activity of single nanoparticles with optical microscopy ». Chemical Society Reviews 47, n^o 7 (2018) : 2485–508. http://dx.doi.org/10.1039/c7cs00451f.

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Chemical activity of single nanoparticles can be imaged and determined by monitoring the optical signal of each individual during chemical reactions with advanced optical microscopes. It allows for clarifying the functional heterogeneity among individuals, and for uncovering the microscopic reaction mechanisms and kinetics that could otherwise be averaged out in ensemble measurements.

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Meher, Anil Kumar, et Yu-Chie Chen. « Online monitoring of chemical reactions by polarization-induced electrospray ionization ». Analytica Chimica Acta 937 (septembre 2016) : 106–12. http://dx.doi.org/10.1016/j.aca.2016.07.011.

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Fligge, Thilo A., Jürgen Kast, Kai Bruns et Michael Przybylski. « Direct monitoring of protein-chemical reactions utilising nanoelectrospray mass spectrometry ». Journal of the American Society for Mass Spectrometry 10, n^o 2 (février 1999) : 112–18. http://dx.doi.org/10.1016/s1044-0305(98)00131-7.

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Sunkara. « On the Properties of the Reaction Counts Chemical Master Equation ». Entropy 21, n^o 6 (19 juin 2019) : 607. http://dx.doi.org/10.3390/e21060607.

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The reaction counts chemical master equation (CME) is a high-dimensional variant ofthe classical population counts CME. In the reaction counts CME setting, we count the reactionswhich have fired over time rather than monitoring the population state over time. Since a reactioneither fires or not, the reaction counts CME transitions are only forward stepping. Typically thereare more reactions in a system than species, this results in the reaction counts CME being higher indimension, but simpler in dynamics. In this work, we revisit the reaction counts CME frameworkand its key theoretical results. Then we will extend the theory by exploiting the reactions counts’forward stepping feature, by decomposing the state space into independent continuous-time Markovchains (CTMC). We extend the reaction counts CME theory to derive analytical forms and estimatesfor the CTMC decomposition of the CME. This new theory gives new insights into solving hittingtimes-, rare events-, and a priori domain construction problems.

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Moser, William R., Joseph R. Berard, Peter J. Melling et Robert J. Burger. « A New Spectroscopic Technique for in situ Chemical Reaction Monitoring Using Mid-Range Infrared Optical Fibers ». Applied Spectroscopy 46, n^o 7 (juillet 1992) : 1105–12. http://dx.doi.org/10.1366/0003702924124204.

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A new versatile spectroscopic technique for chemical reaction monitoring using mid-range infrared optical fibers has recently been developed. Chalcogenide glass optical fibers were used to direct infrared radiation from an FT-IR spectrometer through ZnSe Cylindrical Internal Reflectance (CIR) crystals embedded within laboratory scale reactors. The utility of this technique for studying chemical systems was demonstrated by monitoring various stoichiometric reactions at ambient conditions. A laboratory-scale glass reactor fabricated with the capability to mount a CIR crystal was used as the reaction vessel. The ability of this system to monitor high-pressure and/or high-temperature chemical reactions was also demonstrated by studying the cobalt catalyzed hydroformylation of olefins. A stainless steel CIR reactor, slightly modified to allow for connections with optical fibers, was used for experiments ranging from 50 to 90°C and under 750 to 800 psi synthesis gas (H2/CO mixture). In all cases sufficient signal strength at the detector and adequate penetration into the bulk reaction medium was achieved, resulting in infrared spectra of high quality and resolution. Spectral scans of the reaction in progress allowed the accurate determination of the concentration of reactants and products as a function of time.

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Reis, M. M., M. Uliana, C. Sayer, P. H. H. Araújo et R. Giudici. « Monitoring emulsion homopolymerization reactions using FT-Raman spectroscopy ». Brazilian Journal of Chemical Engineering 22, n^o 1 (mars 2005) : 61–74. http://dx.doi.org/10.1590/s0104-66322005000100007.

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Steinbach, Julia C., Markus Schneider, Otto Hauler, Günter Lorenz, Karsten Rebner et Andreas Kandelbauer. « A Process Analytical Concept for In-Line FTIR Monitoring of Polysiloxane Formation ». Polymers 12, n^o 11 (25 octobre 2020) : 2473. http://dx.doi.org/10.3390/polym12112473.

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The chemical synthesis of polysiloxanes from monomeric starting materials involves a series of hydrolysis, condensation and modification reactions with complex monomeric and oligomeric reaction mixtures. Real-time monitoring and precise process control of the synthesis process is of great importance to ensure reproducible intermediates and products and can readily be performed by optical spectroscopy. In chemical reactions involving rapid and simultaneous functional group transformations and complex reaction mixtures, however, the spectroscopic signals are often ambiguous due to overlapping bands, shifting peaks and changing baselines. The univariate analysis of individual absorbance signals is hence often only of limited use. In contrast, batch modelling based on the multivariate analysis of the time course of principal components (PCs) derived from the reaction spectra provides a more efficient tool for real-time monitoring. In batch modelling, not only single absorbance bands are used but information over a broad range of wavelengths is extracted from the evolving spectral fingerprints and used for analysis. Thereby, process control can be based on numerous chemical and morphological changes taking place during synthesis. “Bad” (or abnormal) batches can quickly be distinguished from “normal” ones by comparing the respective reaction trajectories in real time. In this work, FTIR spectroscopy was combined with multivariate data analysis for the in-line process characterization and batch modelling of polysiloxane formation. The synthesis was conducted under different starting conditions using various reactant concentrations. The complex spectral information was evaluated using chemometrics (principal component analysis, PCA). Specific spectral features at different stages of the reaction were assigned to the corresponding reaction steps. Reaction trajectories were derived based on batch modelling using a wide range of wavelengths. Subsequently, complexity was reduced again to the most relevant absorbance signals in order to derive a concept for a low-cost process spectroscopic set-up which could be used for real-time process monitoring and reaction control.

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AHSAN, HASEEB. « Clinical Chemistry and Biochemistry : The Role of Biomarkers and Biomolecules ». Asian Journal of Science Education 4, n^o 1 (22 avril 2022) : 17–24. http://dx.doi.org/10.24815/ajse.v4i1.24431.

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Biochemistry is a branch of biosciences which deals with the study of chemical reactions that occur in living cells and organisms. It is a subject in which biological phenomenon is analyzed in terms of chemical reactions or metabolic pathways. Biochemistry has been previously named as biological chemistry, chemical biology, clinical chemistry, chemical pathology, physiological chemistry, including medical biochemistry and clinical biochemistry. Medical biochemistry studies the chemical composition and physiological reactions in the human body. Clinical biochemistry is the measurement of chemicals or analytes in body fluids for the diagnosis, monitoring and management of patients with various diseases such as diabetes, cardiovascular diseases, etc. An increase in the number and availability of laboratory diagnostics has helped in the solution of clinical problems. Particularly important is the contribution of clinical chemistry to the diagnosis and monitoring of diabetes. The importance of lipids and lipoproteins for public health has increased with clinical studies showing the benefit of lipid lowering in cardiovascular diseases. An understanding of clinical chemistry and biochemistry would be useful in the study of medical and allied sciences for the advancement of knowledge in academic and professional courses. This review article is an attempt to understand the scope and significance of basic and applied aspects of biochemistry

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Bosch, P., C. Peinado, V. Martín, F. Catalina et T. Corrales. « Fluorescence monitoring of photoinitiated polymerization reactions ». Journal of Photochemistry and Photobiology A : Chemistry 180, n^o 1-2 (mai 2006) : 118–29. http://dx.doi.org/10.1016/j.jphotochem.2005.10.002.

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Salazar, Chase A., Blaise J. Thompson, Spring M. M. Knapp, Steven R. Myers et Shannon S. Stahl. « Multichannel gas-uptake/evolution reactor for monitoring liquid-phase chemical reactions ». Review of Scientific Instruments 92, n^o 4 (1 avril 2021) : 044103. http://dx.doi.org/10.1063/5.0043007.

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Cerdà, Víctor, Carlos Ubide et Juan Zuriarrain. « A multi-syringe flow system for monitoring moderately fast chemical reactions ». Journal of the Brazilian Chemical Society 23, n^o 11 (novembre 2012) : 1989–96. http://dx.doi.org/10.1590/s0103-50532012005000069.

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Simoncelli, Sabrina, Evangelina L. Pensa, Thomas Brick, Julian Gargiulo, Alberto Lauri, Javier Cambiasso, Yi Li, Stefan A. Maier et Emiliano Cortés. « Monitoring plasmonic hot-carrier chemical reactions at the single particle level ». Faraday Discussions 214 (2019) : 73–87. http://dx.doi.org/10.1039/c8fd00138c.

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Palumbo, O., A. Paolone, R. Cantelli, C. M. Jensen et R. Ayabe. « Monitoring of chemical reactions and point defect dynamics in sodium alanates ». Materials Science and Engineering : A 442, n^o 1-2 (décembre 2006) : 75–78. http://dx.doi.org/10.1016/j.msea.2006.02.209.

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Zalduendo, M. Mercedes, Víctor Oestreicher, Judith Langer, Luis M. Liz-Marzán et Paula C. Angelomé. « Monitoring Chemical Reactions with SERS-Active Ag-Loaded Mesoporous TiO2 Films ». Analytical Chemistry 92, n^o 20 (21 septembre 2020) : 13656–60. http://dx.doi.org/10.1021/acs.analchem.0c03310.

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Davies, J. I., M. J. Parrott et J. O. Williams. « In-situ monitoring of chemical reactions in MOCVD growth of ZnSe ». Journal of Crystal Growth 79, n^o 1-3 (décembre 1986) : 363–70. http://dx.doi.org/10.1016/0022-0248(86)90462-8.

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Zhang, Ming-Jian, Yandong Duan, Chong Yin, Maofan Li, Hui Zhong, Eric Dooryhee, Kang Xu, Feng Pan, Feng Wang et Jianming Bai. « Ultrafast solid-liquid intercalation enabled by targeted microwave energy delivery ». Science Advances 6, n^o 51 (décembre 2020) : eabd9472. http://dx.doi.org/10.1126/sciadv.abd9472.

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In chemical reactions, the breaking and formation of chemical bonds usually need external energy to overcome the activation barriers. Conventional energy delivery transfers energy from heating sources via various media, hence losing efficiency and inducing side reactions. In contrast, microwave (MW) heating is known to be highly energy efficient through dipole interaction with polar media, but how exactly it transmits energy to initiate chemical reactions has been unknown. Here, we report a rigorous determination of energy delivery mechanisms underlying MW-enabled rapid hydrothermal synthesis, by monitoring the structure and temperature of all the involved components as solid-liquid intercalation reaction occurs using in situ synchrotron techniques. We reveal a hitherto unknown direct energy transmission between MW irradiation source and the targeted reactants, leading to greatly reduced energy waste, and so the ultrafast kinetics at low temperature. These findings open up new horizons for designing material synthesis reactions of high efficiency and precision.

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Zhang, Kaige, Gongke Li et Yuling Hu. « In situ loading of well-dispersed silver nanoparticles on nanocrystalline magnesium oxide for real-time monitoring of catalytic reactions by surface enhanced Raman spectroscopy ». Nanoscale 7, n^o 40 (2015) : 16952–59. http://dx.doi.org/10.1039/c5nr05718c.

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The surface-enhanced Raman spectroscopy (SERS) technique is of great importance for insight into the transient reaction intermediates and mechanistic pathways involved in heterogeneously catalyzed chemical reactions under actual reaction conditions, especially in water.

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Soares, Arianne de Freitas Barros, Francisco Lucas de Lima Carneiro, Juliana Rosa Leite Araújo Pereira, Micael Araújo Pereira, Antonio Tavernard Pereria Neto et Heleno Bispo Da Silva Júnior. « Advancing Chemical Reaction Engineering : Entropy-Based Modeling of Consecutive Reactions ». Revista de Gestão Social e Ambiental 18, n^o 3 (20 décembre 2023) : e04473. http://dx.doi.org/10.24857/rgsa.v18n3-027.

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Purpose: To optimize a complex reactive system involving a consecutive first-order reaction in a Continuously Stirring Tank Reactor (CSTR) using the Direct Entropy Minimization (DEM) methodology, focusing on identifying operational conditions that minimize entropy generation. Theoretical Framework: In chemical engineering, the efficient management process reactions in a CSTR is crucial. Traditionally, this leads to multiple operational points, which may not be optimal in terms of entropy generation. The DEM approach provides a novel perspective in determining the most efficient operational conditions by focusing on entropy production. Method: The study employs the DEM methodology to analyze a CSTR system involved in consecutive first-order reactions. By conducting mass, enthalpy, and entropy balances, the process is optimized, leading to a model that effectively describes the system’s entropy production rate. This method focuses on establishing an optimal relationship between inlet and reaction temperatures to achieve the lowest possible entropy production. Results and Conclusion: The application of DEM identified the global optimal operational condition, contrasting with the multiple conditions suggested by classical methods. This indicates a significant improvement in process performance and efficiency under minimum entropy production conditions. Research Implications: This study emphasizes the importance of entropy management in chemical reaction engineering. The findings demonstrate that a systematic approach to minimizing entropy can lead to significant improvements in process efficiency and sustainability, suggesting a paradigm shift in how chemical processes are optimized. Originality/Value: This research emphasizes the effectiveness of the DEM methodology in optimizing chemical reactions in a CSTR. The approach is innovative in reducing entropy generation, a key factor for sustainable and efficient chemical process operations.

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Naitabdi, Ahmed, Anthony Boucly, François Rochet, Robert Fagiewicz, Giorgia Olivieri, Fabrice Bournel, Rabah Benbalagh, Fausto Sirotti et Jean-Jacques Gallet. « CO oxidation activity of Pt, Zn and ZnPt nanocatalysts : a comparative study by in situ near-ambient pressure X-ray photoelectron spectroscopy ». Nanoscale 10, n^o 14 (2018) : 6566–80. http://dx.doi.org/10.1039/c7nr07981h.

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Bosch, P., A. Fernández-Arizpe, J. L. Mateo, A. E. Lozano et P. Noheda. « New fluorescent probes for monitoring polymerisation reactions ». Journal of Photochemistry and Photobiology A : Chemistry 133, n^o 1-2 (mai 2000) : 51–57. http://dx.doi.org/10.1016/s1010-6030(00)00226-4.

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Vázquez-Vázquez, Carmen, Belén Vaz, Vincenzo Giannini, Moisés Pérez-Lorenzo, Ramon A. Alvarez-Puebla et Miguel A. Correa-Duarte. « Nanoreactors for Simultaneous Remote Thermal Activation and Optical Monitoring of Chemical Reactions ». Journal of the American Chemical Society 135, n^o 37 (9 septembre 2013) : 13616–19. http://dx.doi.org/10.1021/ja4051873.

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Wall, Jennifer F., Franz Grieser et harles F. Zukoski. « Monitoring chemical reactions at the gold/solution interface using atomic force microscopy ». Journal of the Chemical Society, Faraday Transactions 93, n^o 22 (1997) : 4017–20. http://dx.doi.org/10.1039/a704398h.

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Fletcher, Paul D. I., Stephen J. Haswell et Xunli Zhang. « Monitoring of chemical reactions within microreactors using an inverted Raman microscopic spectrometer ». ELECTROPHORESIS 24, n^o 18 (septembre 2003) : 3239–45. http://dx.doi.org/10.1002/elps.200305532.

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Hsieh, Cheng-Huan, Chin-Sheng Chao, Kwok-Kong Tony Mong et Yu-Chie Chen. « Online monitoring of chemical reactions by contactless atmospheric pressure ionization mass spectrometry ». Journal of Mass Spectrometry 47, n^o 5 (mai 2012) : 586–90. http://dx.doi.org/10.1002/jms.2983.

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Oh, Young-Ho, Dong Wook Kim et Sungyul Lee. « Ionic Liquids as Organocatalysts for Nucleophilic Fluorination : Concepts and Perspectives ». Molecules 27, n^o 17 (4 septembre 2022) : 5702. http://dx.doi.org/10.3390/molecules27175702.

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Besides their extremely useful properties as solvent, ionic liquids (ILs) are now considered to be highly instructive tools for enhancing the rates of chemical reactions. The ionic nature of the IL anion and cation seems to be the origin of this fascinating function of ILs as organocatalyst/promoter through their strong Coulombic forces on other ionic species in the reaction and also through the formation of hydrogen bonds with various functional groups in substrates. It is now possible to tailor-make ILs for specific purposes as solvent/promoters in a variety of situations by carefully monitoring these interactions. Despite the enormous potentiality, it seems that the application of ILs as organocatalysts/promoters for chemical reactions have not been fully achieved so far. Herein, we review recent developments of ILs for promoting the nucleophilic reactions, focusing on fluorination. Various aspects of the processes, such as organocatalytic capability, reaction mechanisms and salt effects, are discussed.

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Terazima, Masahide. « Applications of Time-Resolved Thermodynamics for Studies on Protein Reactions ». J 5, n^o 1 (8 mars 2022) : 186–97. http://dx.doi.org/10.3390/j5010014.

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Thermodynamics and kinetics are two important scientific fields when studying chemical reactions. Thermodynamics characterize the nature of the material. Kinetics, mostly based on spectroscopy, have been used to determine reaction schemes and identify intermediate species. They are certainly important fields, but they are almost independent. In this review, our attempts to elucidate protein reaction kinetics and mechanisms by monitoring thermodynamic properties, including diffusion in the time domain, are described. The time resolved measurements are performed mostly using the time resolved transient grating (TG) method. The results demonstrate the usefulness and powerfulness of time resolved studies on protein reactions. The advantages and limitations of this TG method are also discussed.

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Martoglio, Pamela A., David W. Schiering, Matthew J. Smith et Daniel T. Smith. « Direct Monitoring of Combinatorial Chemistry Reactions by Infrared Microspectroscopy ». Microscopy Today 4, n^o 3 (avril 1996) : 22–24. http://dx.doi.org/10.1017/s1551929500067985.

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What is combinatorial chemistry? Combinatorial chemistry is quickly becoming a very popular technique for organic synthesis in the pharmaceutical and biotechnology fields. Basically, combinatorial methods allow one to obtain thousands of derivatives of chemical compounds in a very quick and efficient manner. The method begins when a molecule of interest is attached to resin beads. Once the molecule is attached, a number of reactions can be run on the beads. The beads can be split up into several subsets, and different reactions can be run on each of the subsets. Because the beads are in the solid phase, it is extremely easy to separate the beads from the liquid layer after the reactions have completed.

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Mutter, Fiona E., B. Kevin Park et Ian M. Copple. « Value of monitoring Nrf2 activity for the detection of chemical and oxidative stress ». Biochemical Society Transactions 43, n^o 4 (1 août 2015) : 657–62. http://dx.doi.org/10.1042/bst20150044.

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Beyond specific limits of exposure, chemical entities can provoke deleterious effects in mammalian cells via direct interaction with critical macromolecules or by stimulating the accumulation of reactive oxygen species (ROS). In particular, these chemical and oxidative stresses can underpin adverse reactions to therapeutic drugs, which pose an unnecessary burden in the clinic and pharmaceutical industry. Novel pre-clinical testing strategies are required to identify, at an earlier stage in the development pathway, chemicals and drugs that are likely to provoke toxicity in humans. Mammalian cells can adapt to chemical and oxidative stress via the action of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2), which up-regulates the expression of numerous cell defence genes and has been shown to protect against a variety of chemical toxicities. Here, we provide a brief overview of the Nrf2 pathway and summarize novel experimental models that can be used to monitor changes in Nrf2 pathway activity and thus understand the functional consequences of such perturbations in the context of chemical and drug toxicity. We also provide an outlook on the potential value of monitoring Nrf2 activity for improving the pre-clinical identification of chemicals and drugs with toxic liability in humans.

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Ji, Haifeng. « (Invited) Reaction-Based Microcantilever Sensors ». ECS Meeting Abstracts MA2024-01, n^o 51 (9 août 2024) : 2764. http://dx.doi.org/10.1149/ma2024-01512764mtgabs.

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Microcantilevers (MCLs) have emerged as a cost-effective, label-free, and portable analytical technique for detecting chemical and biological species. The method offers notable advantages, particularly its high sensitivity, enabling the precise detection of cantilever motion at sub-nanometer levels. Furthermore, MCLs can be effectively fabricated into a multi-element sensor array, amplifying their capabilities. While many sensors rely on adsorption-induced frequency or surface stress changes of MCLs, there is a notable gap in the literature. Despite numerous review articles on MCLs, none have specifically focused on summarizing these sensors with an emphasis on reactions. Beyond their role in detecting chemical species, MCLs present a distinctive application in characterizing the morphology and mechanical properties of materials at solid-liquid or solid-gas interfaces during reaction processes. I will discuss the reaction based MCL sensors and also their potential applications in monitoring reactions.

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Alessandrini, S., E. Ferrero et G. Belfiore. « A Lagrangian dispersion model with chemical reactions ». International Journal of Environment and Pollution 44, n^o 1/2/3/4 (2011) : 182. http://dx.doi.org/10.1504/ijep.2011.038417.

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Mohammad, Mahboob, Muhammad Tariq et Muhammad Tahir Soomro. « “Long-life” atom-free radical : Generation and reactions of bromine atom-free radical ». Collection of Czechoslovak Chemical Communications 75, n^o 11 (2010) : 1061–74. http://dx.doi.org/10.1135/cccc2010066.

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In order to study the damaging or beneficial properties of bromine atom-free radical, reaction of the free radical (Br•) with some biologically important compounds were investigated. Br• was generated through electrochemical oxidation of bromide ion (Br–). First the reactivity of Br• atom-free radical vis a vis its dimerization to form Br2, was studied using cyclic voltammetry and spectroelectrochemistry. Through these techniques it was ascertained that the substrates understudy and the under experimental conditions used, underwent reactions with Br• and not with dibromine (Br2). The monitoring of the reactions of Br• with glycine and cytosine led us to conclude that whereas cytosine reacted with Br• as simple chemical reaction (EC mechanism), glycine underwent a catalytic reaction (EC′ mechanism).

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Violet, Léo, Alexis Mifleur, Laurent Vanoye, Duc Hanh Nguyen, Alain Favre-Réguillon, Régis Philippe, Régis M. Gauvin et Pascal Fongarland. « Online monitoring by infrared spectroscopy using multivariate analysis – background theory and application to catalytic dehydrogenative coupling of butanol to butyl butyrate ». Reaction Chemistry & ; Engineering 4, n^o 5 (2019) : 909–18. http://dx.doi.org/10.1039/c8re00238j.

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Zhang, Haifeng, et Lianzhu Zhou. « Study on Regenerative Processing Performance of Chlorinated Polyethylene Based on Wireless Network and Artificial Intelligence Technology ». Computational Intelligence and Neuroscience 2022 (19 août 2022) : 1–8. http://dx.doi.org/10.1155/2022/3811320.

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The development of Information Technology has intruded the chemical industry. In the conventional chemical industry, humans are involved in monitoring the chemical evaporation processes. If there is any damage, then humans suffer enormously. These drawbacks are overcome in the chemical industry by implanting the sensors to the required blocks for monitoring the levels of chemical substances. An alert system can be introduced with an artificial intelligence algorithm to regenerate the process using details updated in the database. In this research, the machine-based Time-Temperature Superposition (TTS) method is implemented to monitor the chemical reactions in the chemical component manufacturing company.

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Chen, Xiaoyun, Kshitish A. Patankar et Matthew Larive. « Monitoring Polyurethane Foaming Reactions Using Near-Infrared Hyperspectral Imaging ». Applied Spectroscopy 75, n^o 1 (5 octobre 2020) : 46–56. http://dx.doi.org/10.1177/0003702820941877.

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Polyurethane (PU) foams are finding increasingly wider applications ranging from memory foams and mattresses to cushions and insulation materials. They are prepared by reactions between multifunctional isocyanates and polyols as the two main building blocks, along with other additives, including the blowing agents. A non-contact near-infrared (NIR) hyperspectral imaging (HSI) camera was used in this study to monitor PU foaming reactions between a polymeric methylene diphenyl diisocyanate, polyol, and water. Five foams were prepared with three process variables: water content, mixing time, and catalyst levels. Spectral changes characteristic of the PU reactions were observed and clear difference in kinetics could be effectively extracted from such NIR HSI results. The NIR HSI technology offers two substantial advantages over the conventional Fourier transform- (FT-) NIR systems: (i) faster spectral acquisition time and (ii) higher spatial resolution of line images rather than the point measurement. Examples are provided to illustrate these two advantages. The potential to acquire chemical images of PU foams is also demonstrated.

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Friedrich, D., Ch Kaul, G. Lindner, H. Faustmann et M. Münch. « Acoustic On-Line Monitoring of Chemical Reactions in Liquids with Integrated Temperature Compensation ». Sensor Letters 9, n^o 2 (1 avril 2011) : 714–16. http://dx.doi.org/10.1166/sl.2011.1599.

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