Dissertations / Theses on the topic 'Mécanisme cinétique chimique détaillé'
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Lacroix, Rémy. "Mécanisme cinétique hétérogène détaillé de dépôt de pyrocarbone." Thesis, Vandoeuvre-les-Nancy, INPL, 2009. http://www.theses.fr/2009INPL063N/document.
Industrial Carbon/Carbon composite manufacturing processes consist in the densification of a porous substrate (preform) by deposition of gaseous precursors. The aim of this work was to develop and validate a detailed kinetic mechanism modeling heterogeneous reactions of pyrocarbon deposition by propane pyrolysis. Experiments were carried out using an experimental set-up appropriate for studying the kinetics of hetero-homogeneous reactions. Chromatographic analysis were performed to quantify 29 gas phase species, the deposition rate being measured by weighing. We studied the influence of the following experimental parameters: temperature (900-1050°C), residence time (0.5-4 s), S/V ratio (20-170 cm-1) and composition of the reactor inlet (addition of hydrogen, acetylene and benzene). The heterogeneous mechanism contains 275 surface elementary steps involving 66 surface sites. Kinetic parameters of surface reactions were estimated by analogy with gas phase “prototype” reactions. Simulations were carried out using the Surface Chemkin package. The model is efficient to quantitatively predict the deposition rate as well as the mole fractions of major gas phase species. The mole fractions of minor species are semi-quantitatively predicted. The flow rate analysis demonstrates that the pyrocarbon is mostly formed by deposition of methyl radicals and small unsaturated species (acetylene, ethylene) in our experimental conditions
Dmitriev, Artëm. "Kinetic study of ester biofuels in flames." Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0238.
Global progress all over the world requires a variety of clean energy sources. Liquid ester-based biofuels seem to be very effective in this context since they are easy to use in modern vehicles, they can be produced from a variety of renewable resources, and they provide environmentally friendly combustion characteristics. In this regard, fatty acid ethyl esters (FAEEs) are considered as a promising class of biofuels. The main goal of this thesis was to develop an updated chemical kinetic mechanism of combustion of light FAEEs up to ethyl pentanoate and validate it against the new experimental data on chemical speciation in low and atmospheric pressure premixed laminar flames. The flames fueled by three FAEEs, ethyl acetate, ethyl butanoate and ethyl pentanoate, were investigated by means of molecular-beam mass-spectrometry and gas-chromatography. More than 40 stable and intermediate species including radicals were detected and quantified in the flames. A comprehensive analysis of the developed mechanism was performed. The thesis consists of 3 chapters. In the first chapter a review of literature is presented. The most important experimental and theoretic studies on FAEEs are discussed. The second chapter presents an overview of experimental and simulation methods used in the work. Details on the mechanism development are also provided in this part. The last chapter present experimental and modeling results on the esters studied in comparison with the literature kinetic mechanisms
Demenay, Aurélien. "Estimation des sensibilités des matériaux énergétiques soumis à divers stimuli. Interprétation de la sensibilité à l’aide de mécanismes cinétiques détaillés." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLY007.
The main aim of this work is to elaborate predictive tools allowing sensitivity estimation of energetic materials submitted to various stimuli. The main work concerns the calculation of targeted properties of materials having a probable effect on sensitivity predictions. Especially the physico-chemical properties, the thermodynamic properties and properties related to electrostatic potential of the molecule. Prediction is done using correlations established for impact, shock wave, electrostatic discharge, thermal stress and friction. The results are overall good given the current limitations on the subject. Especially there is a lack of quality experimental data and methods for physico-chemical property calculations of energetic materials.The second aim of this work is the study of a potential link between the sensitivity and the auto-ignition delay of energetic materials. Checking this hypothesis requires the development and the use of detailed kinetic mechanisms for a variety of compounds having different sensitivities (RDX, HMX, TNT, TNAZ, NG, PETN, FOX-7, NTO, CL-20). Writing series of reactions, the estimation of rate constants and the calculation of thermodynamic data were carried out. The experimental data available do not allow to validate the mechanisms which must be also improved. At this time it is not possible to assess or not this hypothesis even if trends are such as to confirm it. However, this approach needs to be further worked out
Rullaud, Matthieu. "Modélisation de la combustion turbulente via une tabulation de la cinétique chimique détaillée couplée à des fonctions densités de probabilité. Application aux foyers aéronautiques." Rouen, INSA, 2004. http://www.theses.fr/2004ISAM0004.
Tristant, Pascal. "Mécanisme de la réduction carbothermique du dioxyde de titane : Application à l'élaboration du carbure de titane." Limoges, 1992. http://www.theses.fr/1993LIMO0198.
Soudée, Emmanuel. "Liants phosphomagnésiens : Mécanisme de prise et durabilité." Lyon, INSA, 1999. http://theses.insa-lyon.fr/publication/1999ISAL0049/these.pdf.
Thanks to their rapidly growing resistance, the magnesia-phosphate cements have been widely used for rapid repairing in English-speaking countries. However, the lack of knowledge regarding the mechanism of setting has slowed down their use and the goal of this work is to understand the process of crystal evolution. It was an acid base reaction between magnesia powder and a solution of mono-ammonium phosphate. When being in contact with mixing water, the kinetics of magnesia wetting depends on its surface condition whereas its dissociation is due to the acidity of the solution. Then, Mg2+ ions react with the water molecules to form hydrated compounds, Mg(H2O)62+. These complexes can substitute to water molecules during magnesia wetting and remain stuck on the surface they progressively recover. These surface layer can be the beginning of the crystallization of the struvite network which is made up of PO43-, NH4+ and Mg(H2O)62+ polyhedrons held together by hydrogen bonds
Korovitch, Alexandre. "Mécanisme de formation de complexes de césium : Norbadione A, Dérivés et Calixarènes." Paris 7, 2010. http://www.theses.fr/2010PA077135.
During the Chernobyl disaster in 1986, a cloud of several radioactive isotopes, including Cs was released into the environment. The half-life of ¹³⁷Cs is 30 years. A substantial part of the ¹³⁷Cs was complexed by Norbadione A (NbA) and accumulated in the bay boletus mushroom. This led to contaminations of game meat and people all over Europe. We used the methods and techniques of chemical relaxation (stopped-flow and T-jump) to establish the mechanisms involved in the complex formation between NbA and Cs⁺. One of the major problems encountered with NbA is the diffîculty in detecting the Cs⁺ complex by spectrophotometric techniques. To overturn this obstacle, we used two Cs⁺-selective fluorescent calix[4]arene probes. Complex formation between Cs⁺ and the two calixarenes is slower than expected (few ms). This can be related to the rigid structure, the steric effect and other factors which lead to the necessity of the calixarene cavity to adapt its size and conformation to the large Cs⁺ alkali cation. We determined the mechanisms involved in the complex formation between NbA and Cs⁺ and measured the implicated kinetics and thermodynamics constants in alcohol and aquo-alcoholic mixtures. NbA forais strong complexes with Cs+ ((K₁ ≈ 10⁵ and K₂ ≈ 10³, in ethanol). Complex formation occurs with the two enolates and the two carboxylates of NbA. This affïnity for Cs⁺ can be related to the flexibility of the two pulvinic acids, allowing them to adopt an inclusion cavity conformation
Simonnet, Marie. "Dissolution de l’oxyde de thorium : cinétique et mécanisme." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112226/document.
Studies of new energy sources are necessary to meet the rising global demand. In the nuclear area, Th-U cycle has been reinvestigated to supplement or replace the currently used U-Pu cycle. This project though needs further improvement to be operated in an industrial plant, especially on the reprocessing process, which consists in fuel dissolution in nitric acid medium, followed by liquid-liquid extraction. Still, unlike uranium, thorium oxide does not dissolve in concentrated nitric acid. Small amounts of fluoride are required to achieve the dissolution. The dissolution is rather slow and HNO₃-HF mixture is very corrosive. The aim of this project is thus to find an efficient dissolution method which both decreases corrosion and improves dissolution rate. The synthetized thorium oxide powder has been dissolved in chosen conditions. Effects of solid parameters, dissolution method and dissolution medium have been studied. Results show a strong dependence on oxide crystallinity. No improvement on dissolution rate was observed with power ultrasounds, except for the temperature increase, which greatly enhances dissolution rate. No other complexing agents than fluoride allows total dissolution. Rising HNO₃ and HF concentrations increases dissolution rate until the amount of fluorides is so high that a precipitate forms at the surface. This study led to the proposal of a dissolution mechanism whose limiting step is the formation of an activated complex. Based on kinetics and equilibrium equations, initial dissolution rate was then written as a function of the different studied parameters. Experimental results were finally fitted by this relation to find kinetics and thermodynamics constants, proving the accuracy of the proposed mechanism
Naubron, Jean-Valère. "Réaction d'échange sur des aminophosphines : mécanisme et stéréochimie. Etudes théoriques et expérimentales." Aix-Marseille 3, 2005. http://www.theses.fr/2005AIX30058.
Nucleophilic substitution reaction of an amino group on a trivalent phosphorus atom by an amine has been investigated. The postulated mechanism based on oxidative addition of the amine on the phosphorus centre, leading to an intermediate hydridophosphorane species, followed by reductive elimination of a second amine molecule, as well as alternative mechanisms, have been dismissed by DFT calculations. Besides, kinetic measurements by 1H NMR showed a spectacular effect of acidic catalysis. Hence, new protocatalytic mechanisms corresponding to various reaction paths and exhibiting low activation barrier, around 10 kcal. Mol-1, are proposed. Therefore, the predicted stereochemistry for the reactions strongly depends on the reaction pathway. The CPCM model was used to take in account solvent effects. Solvent cavity was parameterized to calculate accurately the pKa of phosphazenes and phosphines in acetonitrile
Luche, Jocelyn. "Obtention de modèles cinétiques réduits de combustion : application à un mécanisme de kérosène." Phd thesis, Orléans, 2003. http://www.theses.fr/2003ORLE2019.
Mary, Françoise. "Mise au point d'une méthode d'acétylation douce et efficace d'alcools terpéniques en présence de N,N-diméthylamino-4 pyridine : étude du mécanisme de la réaction et de sa sélectivité." Montpellier 2, 1990. http://www.theses.fr/1990MON20267.
Olowe, A. Abiodun. "Corrosion aqueuse du fer en milieux sulfates : Mécanisme, cinétique et structures." Nancy 1, 1988. http://www.theses.fr/1988NAN10297.
El, Khatib Mazen. "Mécanisme et modélisation des réactions intervenant au cours de la synthèse d'une hydrazine d'intérêt pharmaceutique : le N-amino3-aza bicyclo [3,3,0]octane." Lyon 1, 1994. http://www.theses.fr/1994LYO18994.
Buffard, Aude. "Synthèse et étude mécanistique de nanocristaux d'InP et formation d'hétérostructures." Electronic Thesis or Diss., Paris 6, 2016. http://www.theses.fr/2016PA066295.
This manuscript focuses on the synthesis of InP nanocrystals, their understanding of the mechanisms and the improvement of the optical properties of these objects. The nanocrystals of InP are promising materials for optoelectronic and biomedical applications due to their low toxicity and wide reachable spectral range. However, the synthesis of these nanoparticles is poorly controlled and does not allow to obtain large objects with optical properties comparable to CdSe nanocrystals. The phosphorus precursor commonly used presents a high toxicity and a high cost. The aminophosphine are phosphorus precursors of choice to replace the current one since it has a reduced toxicity and a low cost. A study of different synthesis parameters enabled to highlight the role of some reagents such as primary amines. Through a detailed mechanistic and kinetic study, the understanding of the reactions allows to improve the quality of the synthesized nanocrystals. In order to improve the optical qualities of the synthesized nanocrystals, heterostructures can be formed. InP/ZnS systems allow an increase in fluorescence. However, the deposition material is low. With a view to improve their fluorescence, hybrid heterostructure has been developed. This was developed on nanoplatelets CdSe/CdS as a template. The nanocrystals are surrounded by silica and gold layers which provide good protection concerning the environmental medium. The coupling between the plasmon of the gold and the fluorescence increases the optical properties of the material
Waldschmidt, Audrey. "Mécanisme de formation d'inclusions fluides lors de la croissance cristalline de molécules organiques : l'effet inattendu des gaz comme inhibiteurs de croissance." Rouen, 2011. http://www.theses.fr/2011ROUES038.
This manuscript proposes an original mechanism for the formation of fluid inclusion inside single crystals of five organic molecules. The incidence of crystallization parameters such as the nature of the solvent, the presence of impurities and the nature of gas in solution were studied systematically and rigorously. The large impact of the nature of the gas in solution both on the presence of macroscopic vacuoles and on the global crystal growth kinetics was demonstrated. In particular, it was established that every liquid inclusion contains gaseous matter either as dissolved gas or as nanobubbles, so the equilibrium state of vacuoles is a negative crystal containing a gaseous macrobubble. Finally, the analysis of the asperities on the surfaces involved in the vacuole formation has highlighted that a high surface roughness is a necessary (but not sufficient) condition to initiate a defect. Indeed, the formation of inclusions is caused by the strong physical adhesion of bubbles of gases containing oxygen atoms specifically on rough surfaces, giving rise to a local growth inhibition
MATIGNON, Christophe. "Etude de la détonation de deux mélanges stoechiométriques (CH4/H2/O2/N2 et CH4/C2H6/O2/N2) Influence de la proportion relative des deux combustibles et de la température initiale élevée." Phd thesis, Université de Poitiers, 2000. http://tel.archives-ouvertes.fr/tel-00010305.
Buffard, Aude. "Synthèse et étude mécanistique de nanocristaux d'InP et formation d'hétérostructures." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066295/document.
This manuscript focuses on the synthesis of InP nanocrystals, their understanding of the mechanisms and the improvement of the optical properties of these objects. The nanocrystals of InP are promising materials for optoelectronic and biomedical applications due to their low toxicity and wide reachable spectral range. However, the synthesis of these nanoparticles is poorly controlled and does not allow to obtain large objects with optical properties comparable to CdSe nanocrystals. The phosphorus precursor commonly used presents a high toxicity and a high cost. The aminophosphine are phosphorus precursors of choice to replace the current one since it has a reduced toxicity and a low cost. A study of different synthesis parameters enabled to highlight the role of some reagents such as primary amines. Through a detailed mechanistic and kinetic study, the understanding of the reactions allows to improve the quality of the synthesized nanocrystals. In order to improve the optical qualities of the synthesized nanocrystals, heterostructures can be formed. InP/ZnS systems allow an increase in fluorescence. However, the deposition material is low. With a view to improve their fluorescence, hybrid heterostructure has been developed. This was developed on nanoplatelets CdSe/CdS as a template. The nanocrystals are surrounded by silica and gold layers which provide good protection concerning the environmental medium. The coupling between the plasmon of the gold and the fluorescence increases the optical properties of the material
Gornay, Julien. "Transformation par voie thermique de triglycérides et d'acides gras. Application à la valorisation chimique des déchets lipidiques." Thesis, Vandoeuvre-les-Nancy, INPL, 2006. http://www.theses.fr/2006INPL070N/document.
This thesis presents a new way of chemically upgrading of edible frying oils, by thermal conversion. Edible oils have a strong potential to be upgraded into fuels or chemicals, because they are very rich in triglycerides and free fatty acids. The objectives of this study were triple. Firstly, to propose a process of thermal conversion,that allows for the chemical upgrading of edible frying oils. Secondly, to model and understand the chemical reactions of pyrolysis on the octanoïc acid (whose molecule model was selected to represent edible frying oils which are very complex mixtures). Finally, to validate the pyrolysis mechanism on the octanoïc acid by the software CHEMKIN II
Bounaceur, Roda. "Modélisation cinétique de l'évolution thermique des pétroles dans les gisements." Vandoeuvre-les-Nancy, INPL, 2001. http://docnum.univ-lorraine.fr/public/INPL_T_2001_BOUNACEUR_R.pdf.
The aim of this work is to obtain a better understanding of the reactions involved in the thermal cracking of crude oil in sedimentary basins, and to study its kinetics as a function of temperature and pressure. We study the kinetics of pyrolysis of alkanes at low temperature, high pressure and high conversion and we propose three methods of reduction of the corresponding mechanisms. Several compounds having an inhibiting or accelerating effect on the rate of decomposition of alkanes were also studied. This research led to the construction of a general kinetic model of 5200 elementary steps representing the pyrolysis of a complex mixture of 52 molecules belonging to various chemical families: 30 linear alkanes (from CH4 to C30H62), 10 branched-chain alkanes (including pristane and phytane), 2 naphtenes (propylcyc1opentane and propycyclohexane), tetralin, l-methylindan, 4 aromatics (benzene, toluene, butylbenzene and decylbenzene), 3 heteroatomic compounds (a disulfide, a mercaptan and H2S). This model is compared to experimental data coming from the pyrolysis of two oils: one from the North Sea and the other from Pematang. The results obtained show a good agreement between the experimental and simulated values. Then, we simulated the cracking of these two oils by using the following burial scenario: initial temperature of 160°C, 50 m per million years (ma) in a constant geothermal gradient of 30°C/km, implying a heating rate of 1. 5°C/ma. Under these conditions, our model shows that these two oils start to crack only towards 210-220°C and that their time ofhalf-life corresponds to a temperature around 230- 240°C. The model also makes it possible to simulate the evolution of geochemical parameters such as the GOR, the API degree. .
Roy, Marion. "Mécanisme de dissolution des aciers austénitiques dans l'eutectique plomb-bismuth à 500° C." Compiègne, 2012. http://www.theses.fr/2012COMP2054.
In the framework of the future nuclear power plants studies, lead-bismuth eutectic (LBE) is foreseen as a coolant in the primary or the secondary circuit in three nuclear systems. The use of this liquid alloy induces corrosion issues for structural steels. In liquid lead alloys, steels can undergo two corrosion phenomena: dissolution or oxidation depending on the temperature and the dissolved oxygen content in LBE. The goal of this study is to identify the dissolution mechanisms of austenitic steels in LBE at 500 °C. Four Fe-Cr-Ni model austenitic steels, the 316L steel and five other industrial steels were corroded in LBE up to, respectively, 3000, 6000 and 200 h. The dissolution mechanism is identical for all steels: it starts by a preferential dissolution of chromium and nickel. This dissolution leads to the formation of a ferritic corrosion layer penetrated by LBE and containing between 5 and 10 % of chromium and almost no nickel. This study demonstrates that dissolutions of nickel and chromium are linked. Otherwise, the corrosion kinetics is linear whatever the tested austenitic steel. The controlling steps of the austenitic steels’ corrosion rates have been identified. Natural convection in the LBE bath leads to the formation of a diffusion boundary layer at the steel surface. Chromium diffusion in this diffusion boundary layer seems to control the corrosion rates of the model and industrial austenitic steels except the 316L steel. Indeed, the corrosion rate of the 316L steel is controlled by an interfacial reaction which is either the simultaneous dissolution of nickel and chromium in NixCr compounds or the nickel and chromium dissolution catalyzed by the dissolved oxygen in LBE. This study has permitted to highlight the major role of chromium on the corrosion mechanisms and the corrosion rates of austenitic steels: the corrosion rate increases when chromium activity increases. Finally, the impact of the dissolved oxygen and the minor alloying elements content on the corrosion rate is discussed. Assuming chromium dissolution catalysis by dissolved oxygen, some recommendations are proposed on the steel composition and the dissolved oxygen content to fix in the liquid alloy in order to limit the corrosion rates of austenitic steels in LBE
Rodrigues, Romain. "Mécanisme et cinétique de la déchloration réductrice de l'hexachlorobutadiène et de l'hexachloroéthane par action de réactifs à base de fer zéro-valent." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30294/document.
This work focused on the reductive dechlorination of hexachlorobutadiene (HCBD) and hexachloroethane (HCA). The first part consisted of experimental measurement of solubility data for both compounds (i) at different temperatures and (ii) in the presence of surfactants. Thermodynamic parameters for dissolution have been calculated in order to propose a physical explacation of the minimum solubility observed between 12 and 45 °C. The second part, based on a preliminary selection of a reaction for its efficiency, aimed to investigate the mechanism of the reductive dechlorination of HCBD and HCA by Pd/Fe microparticles in suspension in polylactic acid. Different experimental conditions have shown that atomic hydrogen is the main reductant of the system. Different kinetic laws were then used for the modeling of the disappearance of HCBD and HCA, taken separately and in mixture
Neveux, Laure. "Étude de la cinétique et du mécanisme de sulfuration de ZnO par H2S." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 2011. http://tel.archives-ouvertes.fr/tel-00785650.
Magalhães, Alvaro Augusto Oliveira. "Étude de couches de conversion chimiques sur les surfaces zinguées : mécanisme de la formation des couches de chromatation et évaluation de couches de conversion alternatives à base de molybdate." Paris 6, 2002. http://www.theses.fr/2002PA066236.
Canet, Lionel. "Etude du mécanisme et de la cinétique du transport biomimétique de cations métalliques à travers une membrane liquide supportée." Montpellier 2, 1999. http://www.theses.fr/1999MON20207.
Turpin, Estelle. "Cinétique et mécanisme de dégradation atmosphérique de trois composés organiques volatils : l'acétone, le phénol et le catéchol." Lille 1, 2004. https://pepite-depot.univ-lille.fr/RESTREINT/Th_Num/2004/50376-2004-189.pdf.
Eraso, Xavier. "Etude et modélisation cinétique individuelle et par regroupements des réactions d’hydrotraitement sur catalyseur commercial CoMo/Al2O3." Thesis, Lille 1, 2011. http://www.theses.fr/2011LIL10195/document.
In the context of a growing demand for fuel, the diversity of feedstocks and the severity of the actual specifications have led to major modifications in the industrial refinery processes for their optimization. The approach of this thesis consists in improve the kinetic descriptions of the hydrotreatment reactions of gas oils to predict the effects of operating conditions and gas oil nature changes in an industrial process simulator. The kinetic has been studied for 7 gas oils with different initial compositions over a CoMo/Al2O3 commercial catalyst for 320-380°C range of temperature and 45MPa total pressure. The methodology used in this work has permitted to cover a total sulfur range from 5000ppm to few ppm corresponding to the deep HDS. A continuous stirred tank reactor (Mahoney-Robinson) has been used to measure the reactions rates. Analytic technics (Sulf UV, CPG-SCD, CPG-NCD, HPLC) have been set to quantify the sulfur, nitrogen and aromatic species present in the gas oils. The influence of H2, H2S, individual sulfur species or reactivity groups of sulfur species, groups of aromatic and nitrogen compounds have been observed. A bi sites kinetic model (hydrogenation and direct desulfurization pathways) for the HDS of the individual sulfur species resulting from a Langmuir-Hinshelwood mechanism has been established with 188 parameters for 33 compounds and has given satisfying results. The H2S is the most inhibiting compound for the direct desulfurization and the di- and tri-aromatics for the hydrogenation. At last, a model for the HDA and HDN of the different identified families is presented as well
Kobl, Kilian. "Aspects mécanistiques et cinétiques de la production catalytique de méthanol à partir de CO2/H2." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAF023/document.
In view of the climate change and the energy transition, this work is part of the ANR project VItESSE2 about renewable electric energy storage and CO2 valorization by methanol hydrogenation on copper catalysts. During this thesis, an analytical method for copper surface measurement by N2O chemisorption was developed. Based on catalytic tests at 50 bar, kinetic models for Cu/ZnO/Al2O3 and Cu/ZnO/ZrO2 catalysts were elaborated. For the study of the mechanism, a diffuse reflection infrared setup was developed in order to study different catalysts for methanol synthesis and water-gas shift reaction. The setup was used for in situ catalytic tests at 34 bar under reaction flow. The study was complemented by temperature programmed desorption experiments with different probe molecules. The results suggest that the Cu/ZnO/ZrO2 catalyst is more selective for methanol than Cu/ZnO/Al2O3 and that a preparation method which favors Cu–ZnO–ZrO2 interactions can be beneficial for catalytic activity
Marques, de Oliveira Paulo Filho. "Investigation of mechanochemical synthesis of condensed 1,4-diazines and pharmaceutically attractive hydrazones." Thesis, Ecole nationale des Mines d'Albi-Carmaux, 2015. http://www.theses.fr/2015EMAC0007/document.
One of the goals of pharmaceutical and chemical industries is the development of green processes that eliminates or reduces the use of solvents. However, avoiding solvents often requires the use of metal catalysts or others, that accelerates chemical reactions, but make the purifications difficult, especially in the case of fine chemical products, such as active pharmaceutical ingredients. The mechanochemistry has emerged as a sustainable way that enables chemical synthesis, including organic molecular transformations, using the mechanical energy. In spite of the recent advances of the methodology, some aspects of the mechanical action still remain to be fully elucidated, mainly concerning the mechanisms. In this thesis, three main axes of mechanochemistry were explored. First, the molecular mechanism of 1,4-diazine mechanosynthesis, mentioning dibenzo[a,c]phenazine (DBPZ) and 2,3-diphenylquinoxaline (DPQ), is investigated by using 13C CP-MAS NMR that reveals intermediate species for DBPZ, and by calorimetric measurements that show continuation of the reaction after grinding for both reactions. The possibility of a concerted mechanism is considered for dibenzo[a,c]phenazine case. The second focus is on 2,3-diphenylquinoxaline product formation. The process parameters for a vibratory ball mill were studied. Grinding material, size and mass of the balls, granulometry of the starting material were assessed, as well as the temperature of the milling media, providing apparent activation energy (Ea). Arrhenius and Eyring-Polanyi plots presented changes in Ea indicating changes in mechanism, which was attributed to a possible mechanically induced eutectic melting after 30°C. Finally, after understanding some fundamentals and processes for those model reactions, the mechanochemical route was successfully applied to solid-state synthesis of pharmaceutically attractive phenolic hydrazones and catalyzed isoniazid derivatives synthesis, by reacting solid aldehydes and hydrazines. In general, the products were obtained in shorter times and in higher yields compared to classical thermal route. The roles of electronic and solid-state reactivity of the hydrazines were discussed. Biological assays demonstrated the great activity of isoniazid derivatives in inhibiting Mycobacterium tuberculosis. The results presented here cover the mechanochemistry at different levels. The fundamental comprehension is still difficult to access due to the complexity of the system, but some advances could be made such as the detection of intermediate species with significant lifetime. The process parameters are equally important to deduce some mechanism, but also for scale up purposes. At last, the mechanosynthesis of hydrazones showed to be a greener route to produce pharmaceuticals, for high screening of new ones, as well as for the synthesis of others, with great purity and waste reduction
Desmarais, Amélie. "Contribution à l'étude du mécanisme de formation des monomères cycliques d'acides gras à partir d'acides gras oméga-3 et leur métabolomique chez le rat." Thesis, Université Laval, 2013. http://www.theses.ulaval.ca/2013/29984/29984.pdf.
Ramalanjaona, Nick. "Etude du rôle de la protéine NCp7 dans le mécanisme d'hybridation de la séquence PBS lors du second saut de brin de la transcription inverse de VIH-1." Strasbourg 1, 2007. http://www.theses.fr/2007STR13160.
The NCp7 protein is a potential target for an anti-HIV therapy since it is involved in numerous stages of the viral cycle, and its sequence is highly conserved. By combining fluorescence spectroscopy and RMN techniques, we showed that NCp7 modifies the conformation of the PBS loop and destabilizes the upper extremity of the stem. Therefore, NCp7 activates the PBS annealing by stimulating the formation of “kissing complexes”, while in absence of protein, the protruding extremity constitutes the main nucleation site. The modifications of PBS loop inferred by NCp7 also allow homodimers of PBS, which probably play a role in the genetic variability of the virus. The spectroscopic properties of the 8-vinyl-déoxyadenosine, a fluorescent analogue of the adenine, were studied. By its properties, this probe seems superior to the 2-AP
Grira, Asma. "Atmospheric degradation of oxygenated Volatile Organic Compounds." Thesis, Rennes 1, 2021. http://www.theses.fr/2021REN1S017.
Oxygenated Volatile Organic Compounds (OVOCs), mainly released from biogenic sources, play a major role in atmospheric chemistry, climate change, environment, and health. These emissions have been recently shown to increase in the case of biotic and/or abiotic stresses. Biogenic OVOCs may undergo a wide variety of reactions, both chemical and photolytic, and they contribute in the formation of Secondary Organic Aerosols (SOAs). These compounds have been detected in various areas, but little is known about their degradation processes under tropospheric conditions. Understanding the oxidation mechanisms of these species is of fundamental interest and yields crucial data for atmospheric models used by policymakers in formulating and deciding strategies for improving air quality. This dissertation aims to improve the current knowledge of those OVOCs behaviors to better understand their impact on atmospheric chemistry. This work reports a detailed study of the atmospheric degradation of C5-C7 unsaturated aldehydes and C5-C8 unsaturated alcohols by ozone, Cl atom, and OH radical. The main objectives were to better understand the reaction mechanism and to feature the SOA formation potential. To achieve these objectives, we focused on four topics: (i) determination of IR and UV spectrum of C5-C7 unsaturated aldehydes, (ii) determination of the rate constant for the studied OVOCs + Oxidant at room temperature, (iii) identification and quantification of the gas-phase products, (iv) determination of the SOA yields. The product studies were investigated both with and without adding an OH radical scavenger. Experiments were performed in eight different static (chambers) or dynamic (flow) reactors, and various analytical techniques were used to investigate the reaction products (FTIR, GC-FID/MS, SPME-GC/MS, HPLC, PTR-ToF-MS, SIFT-MS, PLP-LIF) and SOA formation (SMPS, FMPS)
Bizot, Patrice. "Vers un système expert de conception de mécanismes réactionnels complexes en phase gazeuse : application à la pyrolyse et à l'oxydation de composés organiques." Vandoeuvre-les-Nancy, INPL, 1995. http://www.theses.fr/1995INPL102N.
Guichard, Jordan. "Etude de l'hydrolyse de l'hydrure de lithium." Thesis, Dijon, 2015. http://www.theses.fr/2015DIJOS050/document.
The hydrolysis of LiH at room temperature and under low water vapor pressure (PH2O < 10 hPa) is investigated by thermogravimetry and FTIR spectroscopy with low sample mass. Then, to be closer to industrial conditions, hydrolysis of LiH is studied by manometry either in closed (adjustable PH2O) or open (constant PH2O) system using larger amounts of sample and heavy water. Products of the reaction are characterized by X-ray diffraction and FTIR spectroscopy. The first set of experiments show that the mechanism of hydrolysis starts with the formation of lithium oxide Li2O. Then, when the oxide layer is sufficiently thick, the hydrolysis reaction is followed by the formation of lithium hydroxide LiOH and afterwards with the formation of lithium hydroxide monohydrate LiOH, H2O. Besides, the Li2O/LiOH outer layer forms a protective barrier on the surface of LiH. The second set of experiments clearly highlights for the first time that the hydrolysis reaction occurs in two steps: first water is adsorbed on the LiH surface and then the hydrolysis reaction starts. The reaction rate is however extremely low and only a very small fraction of LiH is hydrolysed. The kinetic can be well predicted by the shrinking-core model limited by the diffusion through the external ash layer (Li2O and/or LiOH). For practical application, it is concluded that if the LiH powder is stored for several years under a controlled atmosphere or in a sealed container where the vapor water pressure is less than 0.04 hPa, there is no major risk of LiOH formation
Franzelli, Benedetta Giulia. "Impact de la description chimique dans la Simulation Numerique Directe et la Simulation aux Grandes Echelles pour la combustion turbulente des foyers aéronautiques." Phd thesis, Institut National Polytechnique de Toulouse - INPT, 2011. http://tel.archives-ouvertes.fr/tel-00662813.
Capitao, Dany. "Formation électro-assistée de monocouches auto-assemblées sur or. Suivi in situ et effets du potentiel appliqué à l'électrode sur le mécanisme de formation." Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCC215/document.
Create specific surfaces appears as a major issue in chemistry. The formation of self-assembled monolayers (SAMs) using sulfur derivatives is one of the most commonly used strategy to modify gold surfaces. Nowadays, the formation mechanism of self-assembled monolayers (SAMs) on gold is still investigated.A new electrochemical approach for SAMs formation has recently been developed allowing an in situ and real time monitoring of the chemisorption of various sulfur compounds including dithiolane derivatives. Unlike standard adsorption methods which consist in a simple immersion, this approach tends to facilitate the chemisorption by polarizing the electrode. The high temporal resolution coupled to this good reproducibility highlight an adsorption mechanism which proceeds by a nucleation-growth process. This type of mechanism, already identified for the SAMs formation in the gas phase, has never been reported in the liquid phase.In addition, this method allows the preparation of binary mixed monolayers in a controlled and predictable manner. Knowing the affinity constants, it is possible to produce SAMs whose surface proportions reflect those in solution.Finally, to better understand the key factors governing the SAMs formation mechanism, a systematic study depending on the nature of the anchoring group has highlighted a significant difference between the different anchoring groups for the kinetics as well as for the stability of the monolayer
Hannauer, Julien. "Stockage solide et génération d’hydrogène : du borohydrure de sodium NaBH4 à l’hydrazine borane N2H4BH3 : catalyse, cinétique et mécanismes." Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10349.
Hydrogen use as a potential alternative solution to fossil fuels is hindered by engineering problems, its storage being one of the most prominent. Various storage methods are under investigation but solid-state storage in chemical hydrides appears to be convenient with regards to their storage capacities, safety and cost. The first part of this thesis deals with the solvolysis reaction of two well known compounds, sodium borohydride NaBH4 and ammonia borane NH3BH3. The hydrogen can be easily released by hydrolysis at ambient temperature. We focused on understanding the kinetics and reaction mechanisms of NaBH4 hydrolysis. Thus, we compared this reaction with NaBH4 methanolysis, and found that the Langmuir-Hinshelwood model well captures the kinetics of the reaction. Concerning the NH3BH3 hydrolysis reaction, we concentrated our efforts on the in situ preparation of highly-active catalysts. This was achieved by studying the spontaneous and catalyzed hydrolysis of NaBH4-NH3BH3 mixtures. The second part of the thesis is dedicated to the development of the N2H4BH3-water system for hydrogen generation. Initial tests using transition metals as catalysts allowed us to determine that the reaction takes place in two steps, the hydrolysis of BH3 and the N2H4 decomposition. Since Rh as catalyst exhibits only a 29 % selectivity for the complete decomposition of N2H4, the strategy was set up to use Ni-Pt bimetallic nanoparticles. It has been found that the selectivity for the reaction is dependent on the Pt content in the Ni-Pt alloy and a selectivity of 93 % was reached in the presence of Ni0,89Pt0,11 nanoparticles
Le, Coq Xavier. "Étude physico-chimique de matériaux réfractaires de type dolomie-carbone, leur oxydation par les GAZ et leur corrosion par un laitier de désulfuration." Nancy 1, 1989. http://www.theses.fr/1989NAN10335.
Husson, Benoît. "Étude en réacteur auto-agité par jets gazeux de l'oxydation d'hydrocarbures naphténiques et aromatiques présents dans les gazoles." Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0041/document.
The study of the oxidation of naphthenic (ethyl-cyclohexane,n-butyl-cyclohexane) and aromatic (ethyl-benzene,n-butyl-benzene, n-hexyl-benzene) hydrocarbons was performed in a jet-stirred reactor (pressure from 1 to10 bar, temperature from 500 to 1100 K, equivalenceratio: 0.25, 1 and2, residence time: 2s). Reaction products were quantified by gas chromatography and identified using mass spectrometry. The influence on the reactivity and the product selectivity of the equivalence ratio, the pressure and the size of the side alkyl chain attached tothe aromatic or naphthenic ringwas determined. The reactivity of ethyl-cyclohexane was also compared to that obtained for two other compounds containing 8 carbon atoms (n-octane and1-octene). The experimental results for ethyl-cyclohexane and n-butyl-benzene have been satisfactorily compared with prediction made using detailed kinetic mechanisms from the literature, except for the naphthenic at temperature below 800 K. A detailed kinetic mechanismfor the oxidation of ethyl-benzene has been developed (1411 reactions, 205 species) and validated from experimental results obtained in this studybut also from results available in literature. This mechanism has now becomethe "aromatic base" implemented in the software EXGAS Alkyl-aromaticswhich has been developed together with this PhD work and which allows theautomatic generation of alkyl-aromatics oxidation kinetic mechanisms. A study of the generic rules of decomposition of primary species in the secondary mechanism of this softwarewas conducted in this thesis
Mauve, Caroline. "Production et hydrolyse des amides : mécanismes chimiques, isotopie et applications : étude de la glutamine synthétase." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112397.
Nitrogen nutrition in bacteria and plants is currently an important topic, in particular to identify key points for metabolic improvements in N assimilation and more generally, to optimize fertilization and crop yield. In such a context, the amidation reaction catalyzed by glutamine synthetase (GS), which fixes ammonium (NH₄)⁺ into glutamine, is of crucial importance since it both represents the N entry in plants and the main step of N recycling (such as photorespiratory (NH₄)⁺. Here, we examined GS kinetics and chemical mechanism. Analytical methods (HPLC, NMR, GC-MS) have been set up so as to measure in vitro activities and isotopic abundance by isotope ratio mass spectrometry. These gave access to isotope effects (¹²C/¹³C, ¹⁴N/¹⁵N et H₂O/D₂O – solvent) during catalysis, with the GS from either E. coli or A. thaliana (GS1,2). Our results show that there no ¹²C/¹³C isotope effect but there is significant ¹⁴N/¹⁵N isotope fractionation of ca. 16‰. In addition, there is an inverse solvent isotope effect (reaction 1.5 to 2 times faster in D₂O). This suggests that forming the C----N bond (amidation) is partially rate-limiting (catalytic commitment of ca. 14% only) and the H-bond network in the active site is of substantial importance for the reaction rate. The occurrence of inverse ¹⁴N/¹⁵N isotope effects under certain circumstances as well as the drastic impact of changing the metal cofactor (Mg²⁺)) indicate that the amidation step can be reversible and that the coordination by the metal plays a key role in stabilizing reaction intermediates, by interfacing the solvent. In other words, in its natural solvent H₂O, the GS catalyses an intrinsically ‘difficult’ reaction (high energy barrier of amidation) made possible by both ATP cleavage and its exergonic nature
Tilland, Airy. "Étude de l’évolution de la réactivité des matériaux porteurs d’oxygène dans un procédé de combustion en boucle chimique." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0218/document.
The Chemical Looping Combustion (CLC) process produces energy by combustion of methane while capturing the carbon dioxide (CO2). An oxygen carrier (NiO/NiAl2O4) is used to deliver oxygen during the combustion of methane. It is then regenerated by air. The oxygen carrier material degrades over time, which increases the costs of the process and reduces its performance. The present study aims at determining the impacts of thermal and chemical phenomena on the oxygen carrier degradations. The reaction mechanisms corresponding to the reduction and oxidation of the oxygen carrier are determined and validated through experimental studies and the modeling of a continuously auto-stirred tank reactor (CASTR) and a plug flow reactor. The importance of controlling the quantity of deposited carbon in the process is illustrated. Then, the kinetic parameters of the reactions representing the reduction of nickel oxide are determined with an original model of the CASTR and validated in the plug flow reactor. The interest of using the CASTR for the determination of kinetic constants of the reactions involved in CLC process is presented. The obtained parameters give a good description of all reactions even if additional work is required to obtain a better precision of the results. Finally, a degradation mechanism of the oxygen carrier has been proposed. This mechanism describes the large production of fine particles separated from the grains and their role in the observed agglomeration phenomena. The support material, supposed to be inert, provides some of its oxygen. The methodology developed in this work could be adapted for the analysis and the characterization of other oxygen-carriers
Thinon, Olivier. "CO conversion over dual-site catalysts by the Water-Gas Shift Reaction for fuel cell applications : comparative mechanistic and kinetic study of gold and platinum supported catalysts." Thesis, Lyon 1, 2009. http://www.theses.fr/2009LYO10187.
The Fuel Cells are promising solution to reduce the air pollution. One of the cost-efficient alternatives is to produce hydrogen from another fuel such as methane or bio-ethanol. A hydrogen fuel processor consists in generating a hydrogen-rich mixture and reducing the carbon monoxide content, as PEM fuel cells are very low CO tolerance. One of these units is the water-gas shift reactor, which converts CO into CO2 by the reaction with water and provides additional hydrogen. Catalysts based on a metal (Pt, Pd, Ru, Rh, Au, Cu) supported on an oxide (CeO2, TiO2, ZrO2, Fe2O3, CeO2/Al2O3) were compared for the WGS reaction in the same conditions and in the presence of CO2 and H2. A kinetic study was conducted on catalysts Pt/CeO2, Au/CeO2, Pt/TiO2 and Au/TiO2. A power law rate model was used to determine apparent activation energies and reaction orders. A dual-site reaction mechanism was proposed to explain the different activities between the four catalysts. The sorption parameters of H2O and CO2 on the supports was quantitatively determined from temperature-programmed desorption experiments
Nguyen, Van Phuc. "Étude expérimentale et modélisation des interactions entre H2S et les hydrocarbures. Formation de composés organo-soufrés et effets cinétiques en gisement." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0292/document.
H2S can be a dominant gas in carbonate petroleum reservoirs. However, researches on the influence of H2S on the oil stability are limited in literature. In this thesis, interactions between hydrocarbons (oils, model compounds) and H2S were studied by confined pyrolysis in gold cells from 310 to 350°C under 700 bar. Results of pyrolysis of oil (free of sulfur) in presence of H2S lead to highlight a new pathway of formation of organic sulfur compounds in oils. Pyrolysis of binary mixtures n-octane/H2S and alkylbenzène/H2S allowed to propose different radical reactions for the generation of main sulfur products, namely, thiophene, thiols, thiacycloalkanes, alkyl-thiophenes in the first case ; thiol-aromatics, alkyl-benzothiophenes in the second. Results obtained in the mixture n-octane/H2S led to construct and validate a detailed mechanistic model. The mechanism shows that pyrolysis of n-octane/H2S occurs in long chain and H2S has an inhibition effect on the consumption of n-octane at temperatures above of 320°C, but accelerate the reaction rate strongly at low temperatures. Extrapolation of the kinetic model to geological temperatures and pressures (150-200°C, 700 bar) shows that H2S can significantly influence the composition and stability of hydrocarbons. It is also proposed to apply the model to study the reactivity of H2S under conditions of enhanced recovery (steam injection, pyrolysis) or of geological storage in depleted petroleum reservoirs
Gabsi, Wahiba. "APPLICATION DE L’EQUATION DE MAYR A LA QUANTIFICATION DE LA REACTIVITE ELECTROPHILE ET NUCLEOPHILE DE DERIVES THIOPHENIQUES." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLV027/document.
The aim of this work is to study the nucleophilic reactivity of a series of 3-X-thiophenes (X = OC2H5, CH3, H et Br) and the electrophilic reactivity of a series of 3-X-5-nitrothiophenes (X = NO2, CN, SO2CH3, CONH2 et H).According to the free energy relationship log k = s(N + E), the nucleophile-specific parameters N and s of 3-X-thiophenes have been evaluated and compared with the reactivities of other C-nucleophiles in acetonitrile. On the other hand, the satisfactory Hammett correlations (log k1 vs. obtained confirms that a 3-X substituent exerts an effect on the 2-position of the same type as that exerted from the 5-position (hyper-ortho correlations).Kinetics of the reactions of 3-5-dinitrothiophene and 3-cyano-5-nitrothiophene with a series of para-substituted phenoxide anions have been investigated in aqueous solution at 20 °C. Two unsubstituted electrophilic centers of these thiophenes were identified. The electrophilicity parameters E of the C-4 and C-2 positions of the two thiophenes were determined and compared with the reactivities of other ambident electrophiles. Analysis of the experimental data in terms of structure-reactivity relationships reveals that the reactions mechanism likely involves a single electron transfer (SET) process. It is of particular interest to note that the systems studied in this paper provide a rare example of a SET mechanism in σ-complexation reactions
Duchatel, Xavier. "Dégradation thermo-oxydante du poly(fluorure de vinylidène)." Rouen, 1996. http://www.theses.fr/1996ROUES009.
Batiot, Benjamin. "Etude expérimentale et numérique de la décomposition thermique du bois résineux." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2014. http://www.theses.fr/2014ESMA0009/document.
Fires are complex and a variety of phenomena are involved. In order to study them, the up-scaling approach separates all the processes.Among them, the solid thermal decomposition has an important role to play. Source term, it reflects the amount, rate and nature of volatile compounds emitted and its numerical description is essential. The models used currently are formed by a law of variable speed (the Arrhenius law) coupled with a conversion function of mass for each species and a kinetic mechanism organizing all reactions between them. However, this model is based on the theories used in the gas phase and serious doubts might be raised with regard to the representativeness for application in the condensed phase.The thesis works exposed in this report are focused on the model development departing from the reactions and the processes the more fundamental in the condensed phase in order to permit the simulation of the solid kinetic decomposition. The second aspect concerns the study of this model to determine the resolution and the optimization method the most appropriate, the role of each parameter, the possible compensation mechanisms and the uniqueness of the solution.Finally, the entire process is applied to a complex material, the wood. The results obtained from a new approach developed in this work, show a significant improvement of the model to the physical and chemical aspects of the thermal degradation of solid materials
Kim, Youngseob. "Air quality modeling : evaluation of chemical and meteorological parameterizations." Phd thesis, Université Paris-Est, 2011. http://pastel.archives-ouvertes.fr/pastel-00667777.
Mansour, Mounir. "Etude expérimentale et modélisation de l’oxydation sèche d’une poudre de nanoparticules de cuivre." Thesis, Saint-Etienne, EMSE, 2013. http://www.theses.fr/2013EMSE0697/document.
The oxidation of copper nanoparticles at 120 – 145°C was investigated using TGA, DSC, XRD, SEM, TEM and nitrogen adsorption techniques (BET, BJH,..). Isothermal and isobaric studies of the oxidation reaction were carried out under various oxygen partial pressures 1 kPa – 40 kPa. The cuprous oxide (Cu2O) (the unique product of the reaction) grows in an anisotropic manner by outward diffusion of the copper. A considerable decrease of the specific surface area and the porosity of the powder during the transformation was highlighted.It was found that working under P(O2) ≤ 4 kPa leads to reaction where nucleation of Cu2O is in competition with its growth. The study of the dependency of the growth rate on the oxygen partial pressure has shown the adsorption of oxygen to be the rate-determining step. However, when the reaction is conducted under P(O2) ≥ 20 kPa, the nucleation occurs instantaneously in the early beginning of the reaction which will be governed by the growth process. Under these latter conditions of oxygen partial pressure the diffusion of copper ionized vacancies becomes the rate determining step. Hence, two kinetic models have been established to interpret the experimental curves in the two different oxygen partial pressure ranges. The expression of the extent of conversion was successfully confronted to the kinetic data up to an extent of conversion corresponding to the slowdown of the reaction. The kinetic model for P(O2) ≤ 4 kPa was coupled with mass and heat transfer within the porous agglomerate to verify if the diffusion of oxygen molecules in pores is in the origin of the reaction slowdown, this latter hypothesis was found not satisfactory
Zogka, Antonia. "Atmospheric degradation of a series of methoxy and ethoxy acetates and n-pentyl acetate." Thesis, Orléans, 2016. http://www.theses.fr/2016ORLE2071/document.
In the context of DISPATMO project (forecast study of pollution risks related to the atmospheric dispersal of chemicals), risk studies linked to the fires and the explosions due to chemical storage were conducted. The purpose of this thesis was to perform a thorough kinetic and mechanistic study to determine the gas phase degradation of one of the main component of Tiflex solvent, the 1-methoxy 2-propyl acetate (MPA). Furthermore, the rate coefficients of OH and Cl with a series of alkoxy acetates widely used in painting and coating industries, 2-methoxy-butyl acetate (2MBA), 3-methoxybutyl acetate (3MBA), methoxy ethyl acetate (MEA), ethoxy ethyl acetate (EEA) and n-pentyl acetate (n-PA), were determined. The experiments were performed employing the pulsed laser photolysislaser induced fluorescence technique, a low pressure flow tube reactor coupled with a quadrupole mass spectrometer and an atmospheric simulation chamber coupled with a GC-FID, a FTIR and a GC-MS using complementary absolute and relative rate methods. The kinetic data were used to derive the Arrhenius expressions as well as to evaluate the environmental fate of the studied compounds such as their lifetimes and the Photochemical Ozone Creation Potential. Besides, the reaction mechanism was investigated, while the major degradation products and their yields were determined in presence of NO. In addition, the UV-Vis absorption cross sections of MPA, 2MBA and 3MBA were measured in order to evaluate their potential photolysis in the atmosphere. The investigation of the chemical processes and the tropospheric lifetimes of the compounds are used as input data in photochemical atmospheric simulation models and in chemical agent atmospheric dispersion models to evaluate their atmospheric impact
Mokrani, Nabil. "Effet des paramètres physiques et d’additifs sur l'allumage du n-décane par claquage laser non résonant." Thesis, Orléans, 2016. http://www.theses.fr/2016ORLE2062/document.
Ignition by non-resonant laser breakdown of quiescent reactive mixtures was considered in this experimental study working with gaseous state. In this work, we mainly study the ignition of n-decane / air (C₁₀H₂₂+N₂+O₂) mixtures. This system is considered promising in different future strategies regarding ignitions systems for internal combustion engines. The breakdown is generated by focusing a high intensity laser beam for a few nanoseconds using Nd: YAG laser operating at 1064 nm, it is chosen as the laser source for all experiments conducted here. The experimental plan conducted allows to examine the effect of physical, optical, thermodynamic (pressure) and chemicals (additives: H₂O, Ar) on the characteristics of the laser ignition. This study implements a statistical approach on all the experimental cases taking into account all the measures during breakdown and combustion. This manuscript provides bibliographic basis for understanding combustion and laser breakdown phenomenology
Andrieux, Jérome. "Stockage de l'hydrogène dans les borohydrures alcalins : hydrolyse du borohydrure de sodium." Phd thesis, Université Claude Bernard - Lyon I, 2009. http://tel.archives-ouvertes.fr/tel-00654299.