Study of sulfur dioxide adsorption on Y zeolite

Sulfur dioxide adsorptive properties of Y zeolite, the structure of which was confirmed by XRD, were investigated at temperatures within the 25200 ºC range and sulfur dioxide concentrations between 0.9 to 6 % (vol./vol.). It was found that this sorbent possesses a relatively high adsorption capacity. The Y zeolite did not lose its activity during 20 adsorption-desorption-regeneration cycles. The manner in which sulfur dioxide is adsorbed on Y type zeolite was also investigated by analyzing the sample with and without adsorbed SO2, using IR spectroscopy, as well as total and Lewis acidity measurements. The sulfur dioxide molecule is probably adsorbed by hydrogen bonding to one or two conveniently positioned surface hydroxyl groups

Déshydrogénation oxydante du n-butane sur des catalyseurs à base de pyrophosphates métalliques

La déshydrogénation oxydante du n-butane a été étudiée sur des catalyseurs à base de pyrophosphates de Ti, Zr, Ce et Sn. Leurs propriétés physico-chimiques (morphologie, structure, composition) ont été suivies par une série de techniques physiques et leurs propriétés catalytiques évaluées entre 410 et 570ʿC. TiP2O7 présente, à 530ʿC, le meilleur rendement : les sélectivités en butènes et butadiène atteignent respectivement 42% et 14% pour une conversion de 25%. L'ajout d'eau a un effet négatif sur les performances catalytiques. Mis à part CeP2O7, qui se transforme en deux phases phosphate de Ce(III) durant la réaction, les catalyseurs restent inchangés et peuvent être classifiés en deux groupes en fonction de mécanisme réactionnel impliqué : le premier avec ZrP2O7, SnP2O7 et TiP2O7 à basse température et le deuxième avec TiP2O7 à haute température. Des mesures de conductivité électrique et des caractérisations par RPE, spectroscopie Raman et TAP ont été mises en oeuvre pour étudier le mécanisme réactionnel. Sur les deux types de catalyseur l'étape initiale d'activation de l'alcane correspond à l'attaque de l'alcane par une espèce O - menant à un radical, mais tandis que le radical formé est rapidement transformé en butène suite à une deuxième abstraction d'hydrogène par un mécanisme similaire sur le premier type de catalyseur, il est piégé dans une lacune anionique ou sur un site acide de Lewis Ti4+ , étant transformé en une espèce alcoxyde ou directement en butènes par l'abstraction d'un proton, sur le deuxième type. Dans le premier mécanisme l'étape limitante est l'attaque de l'alcane par une espèce O - alors que dans le second c'est la réoxydation du site par diffusion de l'oxygène réticulaire ou directement par l'oxygène de la phase gaz. On observe pour TiP2O7 entre 400 et 450ʿC une situation particulière dont l'étape limitante est toujours l'attaque de l'alcane par une espèce O - mais l'intermédiaire réactionnel peut également être piégé sur le catalyseur.LYON1-BU.Sciences (692662101) / SudocSudocFranceF

Selective oxidation of isobutane on V–Mo–O mixed oxide catalysts

Four V–Mo–O mixed metal oxides were prepared, characterized and tested for the selective oxidation of isobutane in the temperature range 350–550 °C, at atmospheric pressure. Isobutane was mainly oxidized to iso-butene and carbon oxides. The systems with low vanadium contents showed low activities but high isobutene selectivities, while the systems with high vanadium contents showed high activities with high carbon oxides selectivities. The effects of temperature, contact time and the molar ratio iso-butane to oxygen on the conversion of isobutane and the selectivity of the oxidation were studied

Organizational Culture Change in Agile Transformations - Leaders Supporting Agile Mindset Adoption

Agile methodologies have gained popularity for their ability to help companies respond quickly to changing environments and customer needs. However, organizations often struggle with adopting agile methodologies due to their focus on implementing specific frameworks rather than fostering an agile mindset in their organizational culture. Therefore, it is important to promote an agile mindset within organizations and gradually embed it into their culture. This thesis aims to explore how organizational leaders can support the agile mindset adoption. After a thorough review of the relevant literature, the study collected empirical data via interviews with leaders, agile experts and professionals with extensive experience in agile environments to identify practical approaches to support the adoption of an agile mindset that may require an organizational culture transformation. Overall, the outcome of this study contributed to increasing the chances to realize the benefits of agile transformations by fostering the agile mindset

Organizational Culture Change in Agile Transformations - Leaders Supporting Agile Mindset Adoption

Agile methodologies have gained popularity for their ability to help companies respond quickly to changing environments and customer needs. However, organizations often struggle with adopting agile methodologies due to their focus on implementing specific frameworks rather than fostering an agile mindset in their organizational culture. Therefore, it is important to promote an agile mindset within organizations and gradually embed it into their culture. This thesis aims to explore how organizational leaders can support the agile mindset adoption. After a thorough review of the relevant literature, the study collected empirical data via interviews with leaders, agile experts and professionals with extensive experience in agile environments to identify practical approaches to support the adoption of an agile mindset that may require an organizational culture transformation. Overall, the outcome of this study contributed to increasing the chances to realize the benefits of agile transformations by fostering the agile mindset

Dipyridopyrazines et dihydrodipyridopyrazines (synthèse et fonctionnalisation)

Le cancer constitue l une des principales causes de mortalité, plus particulièrement dans l ensemble des pays développés, ce qui, de ce fait, représente aujourd hui un problème de santé publique majeur.L un des axes de recherche du Laboratoire porte sur la synthèse et l étude de la réactivité des hétérocycles azotés. Les systèmes comportant des entités azotées fusionnées à des noyaux pyridiniques sont habituellement dotés de propriétés pharmacologiques intéressantes.La synthèse de dihydrodipyridopyrazines, famille de composés polycycliques aromatiques possédant des propriétés anticancéreuses avérées, a déjà été réalisée au sein du Laboratoire.Dans la mesure où les dihydrodipyridopyrazines sont générées par une réaction arynique conduisant à un mélange d isomères et ce, avec un rendement global n excédant pas 50%, nous avons, au cours de cette thèse, mis au point une séquence univoque d accès à chacun de ces isomères. Après avoir envisagé un schéma mettant en œuvre des réactions de substitution nucléophile aromatique qui se sont, en fait, traduites par des substitutions d hydrogène, nous avons fait appel à des séquences organopalladiées suivies de cyclisation intramoléculaire.Une série de composés diversement substitués ont été ainsi synthétisés avec de bons rendements. La réactivité de ces dérivés via des réactions de métallation a également été explorée.ORLEANS-BU Sciences (452342104) / SudocSudocFranceF

Transition metal-containing mixed oxides catalysts derived from LDH precursors for short-chain hydrocarbons oxidation

International audienceMMgAlO mixed oxide catalysts (M= Mn, Fe, Co, Ni, Cu, Zn, Ag and Pd) obtained from layered double hydroxide (LDH) precursors calcined at 1023K were used in the complete oxidation of methane and the oxidative dehydrogenation of propane. The catalysts were characterized by XRD, N2 adsorption, EDX and H2-TPR experiments. In the catalytic complete oxidation of methane, the Pd-based catalyst has been proved the most active, but the less stable catalyst. Other mixed oxides containing transition metals have been tested and their catalytic activity followed the order: MgAlO≈FeMgAlO NiMgAlO > ZnMgAlO > FeMgAlO > CuMgAlO. No straight correlation between the H2-TPR reducibility and the catalytic performances of the samples was found in the oxidative dehydrogenation of propane into propene. The effects of the contact time and of the propane-to-oxygen molar ratio on the catalytic performances of the most active CoMgAlO, MnMgAlO and NiMgAlO mixed oxides have been investigated

Aspects of Design in Low Voltage Resilient Grids—Focus on Battery Sizing and U Level Control with P Regulation in Microgrids of Energy Communities

Energy communities and their resiliency are both relatively new subjects of interest that need deeper analysis. The concepts are emerging in the current trend of energy decarbonization, combined with unpredictable external factors, such as extreme weather, or nearby conflicts, such as wars. To be resilient against electrical network supply outages or heavy blackouts, energy communities need appropriate design of their electrical microgrids to maintain an acceptable level of activity in both normal and critical situations. The paper deals with aspects of the design of the electrical network used by energy communities, seen as microgrids designed to offer an acceptable level of safe operation and energy resilience. While electrical network resilience covers both the public network (main grid) and local microgrid of an energy community, the paper focuses on the safe operation and resilience related to the local microgrid as a distinct goal from the one of preserving the main grid’s functionality. The first section considers definitions of energy resilience and some of the existing preoccupations on the subject. A second section of the paper presents different aspects of the design of a microgrid, with the purpose of increasing its safety in operation and energy community resilience. The section addresses electrical network architectures, multiple roles of storage resources related to prosumers and to islanded microgrids with high-RES penetration, and other aspects such as the impact of electrification of heating through, e.g., heat pumps. The next sections present selected use cases, which develop some of these design aspects by using typical real data for the analysis and assessing solutions to address resilient microgrid challenges. The selected use cases consider simplified approaches for real-time and short-term storage needs and operational use in microgrids, maintaining voltage levels in a high-RES scenario by using battery P control, and optimization of storage resources to cope with the needs. Conclusions are given in a final section, which also presents future work for a presumed continuation with other use cases related to storage means, safe operation, and resilient design of energy communities microgrids