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Síntese de 3-alcoxiacrilamidas a partir de tricloroacetil enol éteres / Synthesis of 3-alkoxy acrylamides from trichloroacetil enol ethersMello, Débora Lombe de 24 February 2012 (has links)
This work reports a effective method for the preparation of a series of the new
3-alkoxy acrylamides of general formula R3HNC(O)CR1=CR2(OR), where R/ R1/ R2 =
Et/H/H, Me/H/Me, -(CH2)2-/H, -(CH2)3-/H; R3 = Allyl, n-Pr, Bn, Phenetyl. However, the
3-alkoxy acrylamides where R/ R1/ R2 = Et/H/H/, Me/H/Me, R3 = Bn, have already
been described in the literature. The 3-alkoxy acrylamides were obtained through
three reaction steps. The first step, β-alkoxyvinyl trichloroacetyl ketones were
synthesized through the acylation of enolethers using trichloroacetyl chloride as the
acylating agent. In the second step, β-alkoxyvinyl trichloroacetyl ketones were
converted to the corresponding β-alkoxyvinyl carboxylic acids from a basic hydrolysis
using a 1 M sodium hydroxide solution. In the third step, β-alkoxyvinyl carboxylic
acids were treated with thionyl chloride, using toluene as solvent, leading to the
corresponding acyl chlorides intermediaries, which were not isolated. The acyl
chlorides were reacted with primary amines such as allylamine, propylamine,
benzylamine, and phenethylamine under basic catalysis of triethylamine, furnishing a
new series of 3-alkoxy acrylamides in good yields of 48-90%. The 3-alkoxy
acrylamides obtained in this study were identified by 1H and 13C Nuclear Magnetic
Resonance spectroscopy, Mass spectroscopy and Elemental analysis.
Keywords: 3-alkoxy acrylamides, β-alkoxyvinyl carboxylic acids, β-alkoxyvinyl
trichloroacetyl ketones, acyl chlorides, amines / Este trabalho apresenta um método eficiente para preparação de uma série inédita de 3-alcoxiacrilamidas de fórmula geral R3HNC(O)CR1=CR2(OR), onde R/ R1/R2 = Et/H/H, Me/H/Me, -(CH2)2-/H, -(CH2)3-/H; R3 = Alil, n-Pr, Bn, Fenetil. Sendo que
as 3-alcoxiacrilamidas onde R/ R1/ R2 = Et/H/H, Me/H/Me, R3 = Bn, já foram descritas anteriormente na literatura. As 3-alcoxiacrilamidas foram obtidas através de três
etapas reacionais, sendo que a primeira etapa constitui-se da acilação dos enol éteres, utilizando cloreto de tricloroacetila como agente acilante. Na segunda etapa as β-alcoxivinil tricloroacetil cetonas sintetizadas anteriormente, foram convertidas
aos respectivos ácidos β-alcoxivinil carboxílicos a partir da hidrólise básica (utilizando solução de NaOH 1 M). Na terceira etapa, os ácidos β-alcoxivinil carboxílicos foram submetidos à reação com cloreto de tionila, utilizando tolueno
como solvente, formando como intermediários os cloretos ácidos, os quais não foram isolados. Posteriormente, esses cloretos ácidos foram submetidos á reação de substituição nucleofílica, utilizando diferentes aminas alquílicas primárias (alilamina,
propilamina, benzilamina, fenetilamina) como nucleófilo, sob catálise básica de trietilamina, promovendo assim, a síntese da série inédita das 3-alcoxiacrilamidas
com bons rendimentos de 48-90%. As 3-alcoxiacrilamidas obtidas neste trabalho
foram identificadas através de técnicas de Ressonância Magnética Nuclear de
Hidrogênio, Ressonância Magnética Nuclear de Carbono-13, Espectrometria de
Massas e Análise elementar.
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Self-assembly of monolayers of aromatic carboxylic acid molecules on silver and copper modified gold surfaces at the liquid-solid interfaceAitchison, Hannah January 2015 (has links)
Exploiting coordination bonding of aromatic carboxylic acids at metal surfaces, this thesis explores new directions in the design and application of self-assembled monolayers (SAMs). The SAMs are investigated using a multi-technique approach comprising of a complementary combination of scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. In addition, the X-ray standing wave technique (XSW) was used to characterise the substrates. The process of layer formation and the final structures of the SAMs are found to be strikingly dependent on the combination of molecule and substrate, which is discussed in terms of the intermolecular and molecule-substrate interactions, bonding geometries and symmetry of the organic molecules. This is illustrated by the dramatic difference between molecular adsorption on Ag and Cu for molecules such as biphenyl-3,4',5-tricarboxylic acid and biphenyl-4-acetic acid. In the case of self-assembly on Cu, the molecule-substrate interactions play a decisive role in the resulting SAM structure, whereas on Ag, the intermolecular interactions dominate over the weaker molecule-substrate binding. This exploration of the balance of interactions that lead to the formation of these SAM structures lays the foundation for a systematic design of the structures and properties of aromatic carboxylic acid based monolayers. Finally, different applications and properties of some SAMs were investigated, namely coordination of a Pd(II) complex to a pyridine/pyrazole terminated molecule adsorbed on Ag. Evidence of coordination of Pd(II) to single molecules was provided by STM, XPS and NEXAFS spectroscopy. Additionally, controlled STM tip induced modification of local areas of a 1,3,5-tris(4-carboxyphenyl)benzene SAM on Ag was performed, opening an exciting prospect for nanoscale molecular manipulation.
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Earth-abundant metal complexes for catalyzed hydroelementation / Réactions d’hydroélémentation catalysées par des complexes des métaux de transition abondantsZheng, Jianxia 07 October 2014 (has links)
Ce travail de recherche est consacré au développement de catalyseurs à base de métaux de transition abondants de la première rangée du tableau périodique, tels que Mn, Fe, et Ni, pour les réactions d'hydro-élémentation. Tout d'abord, l'hydrosilylation de cétones et d'aldéhydes a été accomplie en utilisant un système catalytique simple Ni(OAc)₂ 4H2O/PCy₃ avec le PMHS, silane peu coûteux et stable en tant que source d'hydrure. L'amination réductrice d'aldéhydes avec des amines a également été réalisée avec le même système catalytique et le TMDS, comme silane. Deuxièmement, l’efficacité des complexes de manganèse demi-sandwich CpMn(CO)₂(IMes) a été prouvée pour la réduction des aldéhydes et des cétones en présence de Ph₂SiH₂ (1,5 équiv.) sous irradiation UV. La transformation difficile d'acides carboxyliques en aldéhydes a été effectuée à l'aide de Mn₂(CO)₁₀ et de Et3SiH. Troisièmement, la méthylation des amines secondaires avec le carbonate de diméthyle en tant que source C1 a été démontrée dans des conditions catalytique douces avec [CpFe(CO)₂(IMes)]I. Ensuite, l'hydroboration d'alcènes et d'alcynes fonctionnalisés a été réalisée en présence d’un complexe de fer (0), Fe(CO)₄(IMes) sous irradiation UV. Enfin, la réaction d'hydroboration a été étendue avec succès à la réduction de CO₂ en methoxyboranes avec Fe(CO)₃[P(OPh)₃]₂ en tant que catalyseur et les diverses sources de borane, tels que HBpin, HBcat ou 9-BBN. / This research work deals with the use of the catalysts based on the earth-abundant transition metals of the first row of the periodic table, such as Mn, Fe, and Ni, for hydroelementation reactions. First of all, the hydrosilylation of aldehydes and ketones was accomplished using a simple Ni(OAc)₂ 4H₂O/PCy₃ catalytic system with the inexpensive and stable silane PMHS as the hydride source. The reductive amination of aldehydes with amines was also achieved with the same catalytic system and TMDS, as the silane. Second, the efficiency of manganese half-sandwich complex CpMn(CO)₂(IMes) was exemplified for the reduction of aldehydes and ketones in the presence of Ph ₂ SiH ₂ (1.5 equiv.) under UV irradiation at room temperature. Still with manganese, the challenging transformation of carboxylic acids to aldehydes was performed using commercial Mn₂ (CO)₁₀ and Et₃SiH. Third, the methylation of the secondary amines with dimethyl carbonate as an alternative and safe C1 source was demonstrated under mild conditions with [CpFe(CO)₂(IMes)]I as the catalyst. Then, the hydroboration of functionalized alkenes and alkynes was catalyzed by an iron(0) carbonyl complex Fe(CO)₄(IMes) under UV irradiation. Finally, the hydroboration reaction was successfully extended to the reduction of CO₂ to methoxyboranes with Fe(CO)₃[P(OPh)₃]₂ as the catalyst and the borane sources, such as HBpin, HBcat or 9-BBN.
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Organische Linkermoleküle auf Basis natürlicher Hydroxycarbonsäuren zum Aufbau homochiraler poriger FestkörperstrukturenEißmann, Diana 02 September 2011 (has links)
Das Ziel dieser Arbeit bestand in der Synthese neuartiger homochiraler Molekülstrukturen, welche nach Konzepten des Crystal Engineering über ein starres Grundgerüst sowie koordinationsfähige Haftgruppen verfügen sollten. Unter Verwendung von Wein- und Milchsäure, als Vertreter der natürlich vorkommenden, enantiomerenreinen α-Hydroxycarbonsäuren, konnten die entsprechenden Derivate mit aromatischen und/oder acetylenischen Spacerelementen hergestellt und umfassend charakterisiert werden. Die synthetisierten Wein- und Milchsäureverbindungen sowie die sich von den jeweiligen Weinsäureestern ableitenden TADDOLe wurden außerdem auf ihre optische Aktivität, ihre Affinität gegenüber verschiedenen Lösungsmitteldämpfen, ihr Einschlussverhalten gegenüber achiralen und chiralen Lösungsmitteln sowie ihre Eignung als organische Linker bei der Synthese von metallorganischen Gerüststrukturen untersucht. Mittels Röntgeneinkristallstrukturanalyse konnten die Festkörperstrukturen einiger Derivate aufgeklärt und diese hinsichtlich ihrer Konformation verglichen werden.
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Ferritin-Based Photo-Oxidation of Biomass for Nanoparticle Synthesis, Bioremediation, and Hydrogen EvolutionPetrucci, Oscar 01 December 2013 (has links) (PDF)
The cell is the basic unit of all living organisms. It is an amazing machine capable of self-replicating, growing, and synthesizing and shuttling thousands of compounds. To perform all of these activities the cell needs energy. The original source of energy for all living beings is the Sun. The energy of the sun is collected by the autotrophs (mostly plants) through photosynthesis and stored in the chemical bonds of carbohydrates and lipids through carboxylic acid intermediates; animals use these compounds to obtain the energy for their cells. Most of the energy extracted by the cell comes from the citric acid cycle. Therefore, two crucial energy transfer checkpoints are photosynthesis and citric acid cycle. With growing need for energy, the limited supply of fossil fuel, and the search for a cleaner environment, scientists have turned to the Sun (directly or indirectly through wind, tides, biomass, etc.) to satisfy the needs of modern society trying to reach the dual Holy Grail of energy: harvesting energy through Artificial Photosynthesis and Low Temperature Biomass Oxidation. This work represents one more step toward reaching these Holy Grails. The core reagent used in our technique is ferritin. Ferritin recapitulates some of the essential features of a plant cell: it contains a semiconductor capable of charge separation, like chlorophyll, acts as a membrane to isolate compartments, and has an enzymatic activity that prevents charge build up and oxidative damage. The energy absorbed by ferritin from the artificial “solar” radiation is used to extract reducing equivalents from stable and partially oxidized compounds, mainly carboxylic acids. The energized electrons produced are then used for a number of technical applications, from synthesis of catalytically active nanoparticles, to reductive precipitation of contaminant heavy metals (i.e.: mercury), to hydrogen evolution.
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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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