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D-glucosamine as "green" substrate in synthesis of ligands for asymetric catalysis / D-glucosamine comme "vert" substrat dans la synthèse de ligands pour la catalyse asymétriqueWojcik, Karolina 22 October 2012 (has links)
Plusieurs ligands dérivés de la D-glucosamine, conçus pour différentes réactions catalytiques,ont été synthétisés. Les ligands pour la catalyse homogène basés sur 1,2-glucodiamine ontété préparés, et utilisés dans des réactions d'alkylation allylique, d'hydrogénation et d'additionde Michael.La D-glucosamine a utilisee pour la preparation de catalysateur type de SPAC (SupportedAqueous Phase Catalyst). Ce catalysateur hétérogène été utilisé avec de très bons résultatsdans les réactions de couplage croisé de Suzuki Miyaura. Le catalyseur a également étérecyclé. Des essais de préparation de ligands greffés sur une matrice de silice de type SBA-15ont été réalisés ainsi que des ligands à base de poly (éthylène) glycol. / Several ligands derived from D-glucosamine, designed for different catalytic reactions havebeen synthesized. The ligands for homogeneous catalysis based on 1,2-glucodiamine wereprepared, and used in reactions of allylic alkylation, hydrogenation and Michael addition.Supported Aqueous Phase Catalyst (SAPC) system was prepared from D-glucosamine anduse with very good results in Suzuki Miyaura cross coupling reactions. Catalyst was alsorecycled. Attempt to prepare ligands grafted on SBA-silica matrix were made as well asligands containing poly(ethylene) glycol moiety.
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Étude de ligands de type biguanide dans le couplage de Suzuki-Miyaura dans l'eauFortun, Solène 12 1900 (has links)
No description available.
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Room-Temperature Synthesis of Transition Metal Clusters and Main Group Polycations from Ionic LiquidsAhmed, Ejaz 06 December 2011 (has links)
Main group polycations and transition metal clusters had traditionally been synthesized via high-temperature routes by performing reactions in melts or by CTR, at room-temperature or lower temperature by using so-called superacid solvents, and at room-temperature in benzene–GaX3 media. Considering the major problems associated with higher temperature routes (e.g. long annealing time, risk of product decomposition, and low yield) and taking into account the toxicity of benzene and liquid SO2 in room-temperature or lower temperature synthesis, a soft and sustainable chemical approach has been developed, employing a Lewis-acidic IL [bmim]Cl/AlCl3. This new alternative reaction medium has proven to be an excellent solvent system for the single–step synthesis of main group polycations and transition metal clusters. X-ray diffraction and Raman spectroscopy have been used for the structural characterization of the isolated compounds. Physical properties and quantum chemical calculations of some of the compounds have also been carried out.
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Transformations of Siloxane-Based Materials Toward a Reuse and Recycling Loop: Catalytic Methods and PhotochemistryRupasinghe, Buddhima 25 May 2022 (has links)
No description available.
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Photochemistry of iron(III) with carboxylate-containing polysaccharides for sustainable materialsKarunarathna, Mudugamuwe Hewawasam Jayan Savinda 29 April 2020 (has links)
No description available.
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Chemical methods to increase the reactivity of lignin : In the context of green chemistry and education for sustainable developmentBirgersson, Erica January 2015 (has links)
The research concerning lignin in high value applications has increased during the last years due to its renewability and availability in the black liquor from pulp mills. Today the major part of kraft lignin found in the black liquor is used as fuel to gain energy in the recovery boiler. Lignin functions as natural glue in plants so that the function of kraft lignin as a phenol replacement in wood adhesives has been researched. Due to lignin's low reactivity the molecule must be modified prior to use. Demethylation is a method to increase the phenolic content in lignin to produce more reactive sites. Thiol mediated and iodine mediated demethylation was performed. Demethylated lignin was characterized by changes in phenolic and hydroxylic groups, molecular mass, elemental composition and other properties using methods including UV, SEC and 31 P NMR. The results showed a decrease in the phenolic content contrary to the increase that was expected. Really low yields were also gained which makes the results non-representative. Size evaluation showed that the percentage of high molecular content in the demethylated lignin sample had increased, which point towards the loss of low molecular mass fractions. Due to demethylation lignin may have been more hydrophilic and soluble in DMF and water. In addition to this bond cleavage may have produced smaller fragments which also increase the solubility. The results point towards the loss of smaller fragments in the DMF and water phases. The applied demethylation methods were evaluated in context of green chemistry. Production, waste, involving chemicals and efficiency were discussed and analyzed. The applied demethylation methods use DMF as solvent which is not a green alternative, greener solvents such as water or other energy adding methods could be used to make the process greener. The use ofNaOMe produces methanol as a byproduct which could be eliminated by using NaOH, future studies on the efficiency of the bases in the needs to be done. Nature science has a reputation of being hard and firm. By bringing in social issues in science education new ways of looking at science opens up. A social problem and at the same time an environmental problem in today's society is the large plastic mountain in the Pacific Ocean. An educational material of the "Samhallsfragor med Naturvetenskapligt Innehiill",SNI, (Societal issues with scientific content) principle has been evaluated with respect to the abilities that can developed together with whether students increase their science knowledge through this. The study showed that students can develop almost all abilities described in the curriculum and their knowledge in science by this type of material. Keywords Biomaterial, lignin reactivity, thiol mediated demethylation, iodine mediated demethylation, green chemistry, SNl-fall. / Forskning kring lignin i produkter har ökat under de senaste åren på grund av lignins fornyelsebarhet och tillganglighet i svartluten från massabruken. Idag används den största delen av sulfatligninet från svartluten som bränsle for att producera energi i sodapannan. Lignin fungerar som ett naturligt lim i växter och på grund av detta undersöks funktionen av kraftlignin som fenolersättning i trälim. Med anledning av ligninmolekylens låga reaktivitet behover lignin modifieras fore användning i produkter. Demetylering är en metod för att öka fenolhalten i lignin och skapa en högre reaktivitet. I denna studie utfördes Tiolmedierad och jodidmedierad demetylering. Det demetylerade ligninet utvärderades med avseende på forändringar i fenol-och hydroxylgrupper, molekylvikt, elementarsammansättning och andra egenskaper med hjälp av olika metoder,inklusive UV, SEC och 31 P NMR. Resultaten visade en minskning i fenolinnehall i motsats till den ökning som förväntades. Riktigt låga utbyten påvisades också vilket gör att resultaten inte är representativa. Storleksutvärdering visade att andelen med högt molekylviktsinnehåll i det demetylerade ligninproven hade ökat, vilket pekar mot förlust av lågmolekylära fraktioner. På grund av demetyleringen kan ligninet ha blivit mer hydrofilt och lösligt i DMF och vatten. Utöver detta kan bindningsklyvning ha skapat mindre fragment som också ökat lösligheten. Resultaten pekar mot förlust av mindre fragment i DMF-och vattenfaserna. De tillämpade demetyleringsmetoderna utvärderades med avseende på grön kemi. Produktion, avfall, kemikalier och effektivitet diskuterades och analyserades. De tillämpade demetyleringsmetoderna använder DMF som lösningsmedel, vilket inte är ett grönt alternativ. Grönare lösningsmedel såsom vatten, eller andra typer av energitillsättning, kan användas för att göra processen miljövänligare. Användandet av NaOMe i den thiolmedierade demethyleringen skapar metanol som en biprodukt vilket kan bytas ut mot vatten om NaOH istället används. Vidare studier behöver göras för att undersöka de båda baserna effektivitet. Naturvetenskapen har ett rykte om att vara hård och fast. Genom att föra in sociala frågor i den naturvetenskapliga utbildningen kan nya sätt att se på vetenskapen skapas. Ett samhälls problem och samtidigt ett miljöproblem i dagens sämhalle är det stora plast berget i Stillahavet. Ett undervisningsmaterial för"Samhällsfrågor Med Naturvetenskapligt Innehåll", SNI, principen har utvärderats med avseende på vilka förmågor som kan tränas tillsammans med huruvida eleverna kan öka sin vetenskapliga kunskap. Studien visade att eleverna kan utveckla nästan alia formågor som beskrivs i läroplanen och sina kunskaper inom naturvetenskapen genom denna typ av utbildningsmaterial. Nyckelord Biomaterial, ligninreaktivitet, tiol medierad demetylering, jodmedierad demetylering,grön kemi, SNI-fall.
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Photo-Catalytic Reaction Screening and Catalytic Polymerization of rac-Lactide Studied by Mass SpectrometryJayaraj, Savithra January 2021 (has links)
No description available.
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Photochemistry of Fe(III)-carboxylates in polysaccharide-based materials with tunable mechanical propertiesGiammanco, Giuseppe E. 22 November 2016 (has links)
No description available.
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Strukturiranje polimernih mreža na osnovu akrilamida i akrilne kiseline / Structuring of polymer networks based on acrylamide and acrylic acidErceg Tamara 28 September 2019 (has links)
<p style="text-align: justify;">U ovom radu sintetisani su hidrogelovi na osnovu akrilamida i akrilne kiseline, radikalnom polimerizacijom, primenom konvencionalne i mikrotalasne metode sinteze. Varirani su početni odnosi monomera i udeo umreživača, u cilju ispitivanja uticaja sastava reakcione smeše na svojstva dobijenih hidrogelova. Optimizovani su uslovi sinteze u mikrotalasnom polju kao brže, jednostavnije i ekonomičnije metode. U cilju uspostavljanja korelacije između mehanizma sinteze, strukture i svojstava dobijenih hidrogelova, primenom relevantnih metoda karakterizacije, upoređena su apsorpciona, reološka, toplotna i strukturna svojstva hidrogelova dobijenih dvema metodama. Ustanovljeno je da se mikrotalasnom metodom sinteze na brži i jednostavniji način uz smanjen utrošak vremena i energije dobijaju hidrogelovi konkurentni onima koji se dobijaju konvencionalnim zagrevanjem u vodenom rastvoru. Drugi deo doktorata obuhvata sintezu hidrofilnih polimernih mreža na osnovu natrijum karboksimetilceluloze (NaCMC) i karboksilnih kiselina, od kojih je jedna serija sintetisana prožimanjem linearnim kopolimerima akrilamida i akrilne kiseline u cilju povećanja potencijala primene u floku-lacione svrhe. Rezultati ispitivanja svojstava bubrenja, strukturnih toplotnih i flokulacionih svojstava pokazali su međusobno slaganje. Dobijeni rezultati pokazali su da od primenjenih karboksilnih kiselina, linunska kiselina u udelu od 15% u odnosu na masu NaCMC daje hidrogelove najboljih svojstava. Kombinacijom ove mreže sa kopolimerom akrilamida i akrilne kiseline u masenom odnosu 10/90, stvara se teorijska platforma za dobijanja flokulanta koji bi mogao da pokaže visoku efikasnost u prečišćavanju vode u kojoj dominiraju pozitivno naelektrisane čestice, pravilnim izborom parametara flokulacije.</p> / <p>In this paper, hydrogels based on acrylamide and acrylic acid were synthesized using conventional and microwave synthetic methods via free-radical polymerization. The initial monomers ratio and amount of crosslinking agent were varied in order to investigate the effect of the composition of the reaction mixture on the properties of the obtained hydrogels. The conditions of synthesis in the microwave field as faster simpler and more economical method have been optimized. In order to establish a correlation between the mechanism of synthesis, structure and properties of the obtained hydrogels using the relevant methods of characterization, the absorption, rheological, thermal and structural properties of the hydrogels obtained by the two methods were compared. It has been found that the microwave synthesis is a faster and simpler method, which enables reduced consumption of time and energy and produces hydrogels competitive to those ones obtained by conventional heating in aqueous solution. The second part of the thesis includes the synthesis of hydrophilic polymer networks based on sodium carboxymethylcellulose (NaCMC) and carboxylic acids, whereby one series is synthesized by interpenetration of the network using the linear acrylamide and acrylic acid copolymers in order to increase the potential application of hydrogels for flocculation purposes. The results of measurements of swelling, structural, thermal and flocculation properites have shown mutual agreement. The obtained results have shown that among applied carboxylic acids, citric acid in the amount of 15% per mass of NaCMC, has given the hydrogels with the best properties. The Combination of this network with a copolymer of acrylamide and acrylic acid in a mass ratio of 10/90 has created a theoretical platform for the production of flocculant which could show high efficacy in purifying of water dominated by positively charged particles.</p>
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Nouvelles cibles pour l'étude et le développement d'outils pharmacologiques originaux pour le traitement des douleurs neuropathiques / New targets for the study and development of new pharmacological tools for the treatment of neuropathic painBollenbach, Maud 12 June 2017 (has links)
Les douleurs neuropathiques désignent une hypersensibilité du système nerveux central sensoriel. C’est une maladie chronique et handicapante qui touche environ 6% de la population française. Cependant, à l’heure actuelle, il n’existe pas de traitement spécifique et efficace. Dans le cadre de cette thèse, nous avons utilisé deux stratégies différentes afin de développer des outils pharmacologiques originaux pour traiter ces douleurs : une approche phénotypique autour de deux inhibiteurs de la surproduction de TNFα (un dérivé de 2-aminopyrimidine et un dérivé de pyridin-2-yl guanidine) et une approche moléculaire autour du MY 5445 (un inhibiteur de PDE5 dérivé de phtalazine). En particulier, notre travail s’est basé sur la conception, la synthèse et l’étude des relations structure-activité autour de ces différents hits et nous avons obtenu des composés efficaces par voie i.p. ou per-os sur un modèle murin de douleurs neuropathiques.En parallèle de ce travail de pharmacologie, nous avons développé différents systèmes catalytiques (Pd, Cu) en milieu micellaire afin de former des liaisons C-N à température quasi-ambiante. / Neuropathic pains correspond to a central sensory nervous system hypersensitivity. It is a chronic and disabling disease, which touch around 6% of the French population. Nowadays, there is no specific and efficient treatment. In my PhD project, we used two different strategies in order to develop innovative pharmacological tools to treat those pains: a phenotypic approach around two TNFα overproduction inhibitor (a 2-aminopyrimidine derivative and a pyridin-2-yl guanidine derivative) and a molecular approach around MY 5445 (a phthalazine PDE5 inhibitor). Our work was based on the design, synthesis and structure-activity relationship study around various hits and we obtained compounds i.p. and orally effective on a murin neuropathic pain model.In parallel to this pharmacological work, we developed different catalytic systems (Pd, Cu) under micellar conditions to form C-N bonds at almost room temperature.
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