Orientador: Ulf Friedrich Schuchardt / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-08T20:51:24Z (GMT). No. of bitstreams: 1 Steffen_RafaelAugusto_M.pdf: 657835 bytes, checksum: efc464baf50683cc652c38220caa0600 (MD5) Previous issue date: 2007 / Resumo: Testou-se a atividade catalítica de duas aluminas, uma comercial (Fluka) e outra obtida via processo sol-gel, na oxidação Baeyer-Villiger utilizando cicloexanona como substrato e peróxido de hidrogênio como oxidante. Os catalisadores foram caracterizados por análise termo gravimétrica e difração de raios-X e os produtos identificados por cromatografia a gás e ressonância magnética nuclear de H e C. Os catalisadores mostraram-se altamente eficientes nas oxidações utilizando-se peróxido de hidrogênio aquoso 70 % (m/m) como oxidante, com rendimentos em e-caprolactona superiores a 75 % com seletividade de 98 %. As condições foram otimizadas, sendo 20 h de reação, 90 ± 2 ºC, razão molar de peróxido de hidrogênio:cicloexanona 8:1 e 300 mg de alumina, utilizando-se acetato de etila como solvente, com o sistema acoplado a um Dean-Stark para remoção da água do meio reacional. Os catalisadores apresentaram menores rendimentos na presença de água, perdendo a seletividade já na primeira reciclagem. Porém, nas reações em que se fez a remoção de água os catalisadores mantiveram a mesma atividade catalítica após cinco ciclos. Testes em que se comparou o desempenho do catalisador na epoxidação e na oxidação Baeyer-Villiger mostraram que existe competição entre os sítios ativos dessas reações. Com base nos resultados obtidos propô-se um mecanismo no qual a reação poderá ocorrer por dois caminhos distintos / Abstract: Two aluminas, one comercial (Fluka) and the other obtained by sol-gel methods, were used as catalysts for the Baeyer-Villiger oxidation using cyclohexanone as substrate and hydrogen peroxide as oxidant. The catalysts were characterized by X-ray diffraction and thermogravimetric analysis and the oxidation products were analysed by gas chromatography and H and C nuclear magnetic resonance. Both aluminas showed to be high efficient catalysts for Baeyer- Villiger oxidation with aqueous hydrogen peroxide 70 % (w/w), reaching yields as high as 75 % for the e-caprolactona with selectivity of 98 %. The optimized conditions was found to be 20 h of reaction at 90 ± 2 ºC, with peroxide:cyclohexanone molar ratio of 8:1, 300 mg of catalyst, ethyl acetate as solvent and a Dean-Stark system coupled for water removal. The catalysts showed lower selectivity in the presence of water, losing the activity at the first recycling test. However, when the water was removed, the catalysts presented the same activity in 5 consecutive cycles. Tests comparing the alumina as epoxidation and Baeyer-Villiger oxidation catalyst showed that there is a competition between the catalytic sites for these reactions. Based on the results obtained we were able to propose a mechanism, admitting that the reaction could occur by two different pathways / Mestrado / Quimica Organica / Mestre em Química

La conception de solides à la fois stables en conditions hydrothermales, mais aussi capables de convertir des composés biosourcés en molécules plateformes dans un même lit catalytique, représente un défi majeur en science des matériaux.Dans ce contexte, des oxydes mixtes binaires et ternaires de silice dopée avec les éléments W, Ti, Zr, Nb, Ta et Mg (3 à 20%at.) ont été élaborés via la méthode non conventionnelle de synthèse Sol-Gel Non Hydrolytique (SGNH). Cette méthode permet d’obtenir des oxydes mixtes très homogènes et de moduler finement leurs propriétés via les paramètres de synthèse.Les solides sont majoritairement amorphes et mésoporeux. Les analyses en MET-EDS, FTIR et ToF-SIMS indiquent que les éléments dopants sont bien dispersés dans la silice et que les oxydes mixtes présentent majoritairement une homogénéité allant jusqu’à l’échelle nanométrique voire atomique.Les molécules sondes NH3 et CO révèlent la présence des sites acides de forces faible et moyenne, majoritairement de type Lewis pour l’ensemble des matériaux. La densité de sites acides peut être promue via : l’amélioration du degré d’homogénéité entre les oxydes, l’élaboration d’oxydes mixtes ternaires et l’augmentation de la teneur en éléments dopants.La caractérisation des solides par la réaction modèle de conversion du mélange cyclopentanol/cyclohexanone en phase gaz montre que la majorité des matériaux catalysent à la fois des réactions de déshydratation et de transfert d’hydrogène (réduction MPVO).Après traitement hydrothermal en phase gaz à 400°C, les solides conservent de bonnes textures, en particulier les oxydes mixtes ternaires et dopés à haute teneur.Cette étude montre la versatilité de la méthode de synthèse SGNH et son potentiel pour mettre au point des oxydes mixtes binaires et ternaires très homogènes. Les oxydes mixtes ternaires, contenant 20% d’éléments dopants et contenant du Nb, du Zr ou du Ta sont particulièrement prometteurs pour les applications visées. / The design of new heterogeneous catalysts with good hydrothermal stability that are able to transform bio-based components into building blocks in one single catalytic process is a main challenge in material science.In this context, binary and ternary mixed oxides of silica doped with W, Ti, Zr, Nb, Ta et Mg (3 to 20%at.) have been produced with the non-conventional Non-Hydrolytic Sol-Gel (NHSG) synthesis method. This method enables to obtain highly homogeneous mixed oxides and to finely shape the properties of the material with the synthesis parameters.The solids are mostly amorphous and mesoporous. TEM-EDS, FTIR and ToF-SIMS analysis indicate that the doping elements are highly dispersed in the silica and that most of the mixed oxides display nanometric or atomic scale homogeneity.The NH3 and CO bases show the presence of mostly Lewis weak and medium strength acid sites for these materials. The acid sites density can be improved through: increasing mixed oxide homogeneity, preparing ternary mixed oxides, increasing doping element content.The conversion of the mixture cyclopentanol/cyclohexanone in the gas phase shows that the majority of the materials perform both dehydration and hydrogen transfer reactions (MPVO reduction).After steaming at 400°C, the solids maintain good textures, particularly ternary mixed oxides and mixed oxides containing high dopant content.This study shows the versatility of the NHSG synthesis method and its applicability in order to design binary and ternary mixed oxides. The ternary mixed oxides containing 20%at. of doping elements with Nb, Zr and Ta are promising for the conversion of bio-based compounds.

Naujų 3,5-pakeistų 3-amino-2-tiokso-4-tiazolidinono darinių su cikloheksanono ir ciklopentanono pakaitais sintezė ir antibaktrinio ir priešgrybelinio aktyvumo tyrimas. Lino Remeikio magistro baigiamasis darbas. Mokslinis vadovas: prof. habil. dr. Eduardas Tarasevičius, konsultantas: prof. habil. dr. Alvydas Pavilonis; Lietuvos sveikatos mokslų universitetas. Darbo tikslas - susintetinti naujus antibakterinius ir priešgrybelinius 3-amino-2-tiokso-4-tiazolidinono darinius su pakaitais, esančiais 3 ir 5 padėtyse ir nustatyti N-3 padėtyje esančių pakaitų įtaką junginių priešmikrobiniam aktyvumui. Tyrimo metodai – junginių priešmikrobinis aktyvumas buvo prognozuojamas naudojant PASSonline programą. Antimikrobinis aktyvumas buvo tiriamas in vitro būdu dvigubo serijinio praskiedimo būdu, naudojant standų Miulerio – Hintono agarą. Tyrimo rezultatai – Atlikus prognozes naudojant PASSonline programą, gauti rezultatai nerodė didelio antibakterinio ar priešgrybelinio aktyvumo. Atlikus tyrimus in vitro, pastebėta, jog aktyviausi junginiai N-3 padėtyje turi alifatinius ciklinius ketonus LRT-1; LRT-21 ar C-5 nitrofuraldehido radikalą LRT-3; LRT-23. Įvedus kitus elektronų donorinius pakaitus į penktą padėtį, kai N-3 blokuota, aktyvumas labai sumažėjo. Aktyviausi junginiai savo sudėtyje turi N-3 blokuotą padėtį alifatiniais cikliniais ketonais ir C-5 įvestą nitrofuraldehidą – LRT-3 ir LRT-23. Didelis aktyvumas yra prieš S.aureus, B.subtilis, K.pneumoniae, B.cereus, E.faecalis, C.albicans... [toliau žr. visą tekstą] / Synthesis of new 3,5-substituted 3-amino-2-thioxo-4-thiazolidinone derivatives with cyclohexanone and cyclopentanone substitutes and evaluation of antimicrobial activity. L. Remeikis Master thesis. Scientific supervisor Prof., Habil. Dr. Eduardas Tarasevičius, prof. habil. dr. Alvydas Pavilonis; Lithuania University of Health Sciece. The Aim of Research – to synthesise new 3-amino-2-thioxo-4-thiazolidinone derivatives and evaluate impact of aliphatic cyclic ketone substitutes at N-3 position for antimicrobial activity. Methods – Activity prognosis of new compounds was evaluated using PASSonline program. Antimicrobial activity was testes in vitro, using double serial diliuotn method using Miuler-Hinton agar. Results. Prognosis with PASSonline showed weak activity againt bacteria and fungi. The results of tests in vitro showed that compound LRT-1 and LRT-12 with aliphatic cyclic ketones at N – 3 position characterized medium activity and compounds with 5-nitrofuraldehyde radical at C-5 position (with N-3 position blocked) LRT-3 and LRT-23 showed high activity against S.aureus, B.subtilis, K.pneumoniae, B.cereus, E.faecalis, C.albicans (MSK 1,5625 – 6,25 μg/ml). Other electrone donating substutes at C-5 position (with N-3 blocked) show very weak activity. Conclusions – tests in vitro showed that the most active compounds: LRT-3 and LRT-23 had 5-nitrofuraldehyde fragment in C-5 position and alyphatic cyclic ketone in N-3 position. Test result also showed that cyclic radicals in... [to full text]

Calcando-se na bem conhecida capacidade que os sulfóxidos apresentam em induzir a quiralidade em uma vasta gama de reações, foram preparadas as (±)-2-p-tolilsulfinil-3,6-dimetil- e a (S)-2-p-tolilsulfinil-3-metil-1,4-benzoquinonas e estudadas as suas reações de Diels-Alder com alguns 1,3-dienos. Bons resultados de quimio- e regiosseletividade foram obtidos no caso da primeira quinona com o trans-piperileno e com o 1-vinil-cicloexeno, mas a eliminação espontânea de ácido sulfênico gerou produtos que não puderam ser utilizados posteriormente. O grupo sulfinila, no caso da segunda quinona preparada, não de mostrou capaz de induzir diastereosseletividade facial nas reações com ciclopenta- e cicloexadieno. Também foram estudados os modos de adição do enolato de lítio do acetato de etila às carbonilas das 2-metilsulfinil-2-sulfanil-cicloexanonas. Pelo emprego de espectroscopia de absorção no I. V., ficou evidenciado que a 2-metilsulfinil-2-metilsulfanil-cicloexanona existe como mistura de confôrmeros, sendo o mais abundante aquele para o qual se atribuiu, baseado em cálculos teóricos, que o grupo SOCH3 esteja preferencialmente na posição equatorial e o grupo SCH3, na posição axial. Assim sendo, os excessos enantioméricos observados puderam ser explicados pela proposição de que o ataque do enolato ocorreu de modo axial sobre as carbonilas dos confôrmeros existentes em solução. / Based on the well known ability of the sulfinyl group in controlling the chirality of a broad spectrum of reactions, the new (±)-2-p-tolylsulfinyl-3,6-dimethyl- and (S)-2-p-tolylsulfinyl-3-methyl-1,4-benzoquinones were prepared and their Diels-Alder reactions with some 1,3-dienes investigated. Good chemo- and regioselectivities were observed for the reactions of (±)-2-p-tolylsulfinyl-3,6-dimethylbenzoquinone with both trans-piperilene and 1-vinylcyclohexene. However, spontaneous elimination of sulfenic acid precluded the use of the obtained cycloadducts in further transformations. The sulfinyl group, in the case of (S)-2-p-tolylsulfinyl-3-methyl-1,4-benzoquinone, failed to control diastereoselectivity in Diels-Alder reaction with cyclopentadiene and cyclohexadiene. Studies concerning the addition of ethyl acetate lithium enolate to the carbonyl groups of 2-methylsulfinyl-2-sulfanyl-cyclohexanones were also undertaken. In the case of 2-methylsulfinyl-2-methylsulfanylcyclohexanone, a mixture of conformers was evidenced by I. R. spectroscopy. On the basis of theoretical considerations, it could be advanced that, in the most abundant conformer, the SOCH3 and SCH3 groups lie, respectively, in equatorial and axial arrangements. Therefore, the observed enantiomeric excess can be explained considering that the enolate performs an axial attack to the carbonyl groups of the ketone conformers.

Calcando-se na bem conhecida capacidade que os sulfóxidos apresentam em induzir a quiralidade em uma vasta gama de reações, foram preparadas as (±)-2-p-tolilsulfinil-3,6-dimetil- e a (S)-2-p-tolilsulfinil-3-metil-1,4-benzoquinonas e estudadas as suas reações de Diels-Alder com alguns 1,3-dienos. Bons resultados de quimio- e regiosseletividade foram obtidos no caso da primeira quinona com o trans-piperileno e com o 1-vinil-cicloexeno, mas a eliminação espontânea de ácido sulfênico gerou produtos que não puderam ser utilizados posteriormente. O grupo sulfinila, no caso da segunda quinona preparada, não de mostrou capaz de induzir diastereosseletividade facial nas reações com ciclopenta- e cicloexadieno. Também foram estudados os modos de adição do enolato de lítio do acetato de etila às carbonilas das 2-metilsulfinil-2-sulfanil-cicloexanonas. Pelo emprego de espectroscopia de absorção no I. V., ficou evidenciado que a 2-metilsulfinil-2-metilsulfanil-cicloexanona existe como mistura de confôrmeros, sendo o mais abundante aquele para o qual se atribuiu, baseado em cálculos teóricos, que o grupo SOCH3 esteja preferencialmente na posição equatorial e o grupo SCH3, na posição axial. Assim sendo, os excessos enantioméricos observados puderam ser explicados pela proposição de que o ataque do enolato ocorreu de modo axial sobre as carbonilas dos confôrmeros existentes em solução. / Based on the well known ability of the sulfinyl group in controlling the chirality of a broad spectrum of reactions, the new (±)-2-p-tolylsulfinyl-3,6-dimethyl- and (S)-2-p-tolylsulfinyl-3-methyl-1,4-benzoquinones were prepared and their Diels-Alder reactions with some 1,3-dienes investigated. Good chemo- and regioselectivities were observed for the reactions of (±)-2-p-tolylsulfinyl-3,6-dimethylbenzoquinone with both trans-piperilene and 1-vinylcyclohexene. However, spontaneous elimination of sulfenic acid precluded the use of the obtained cycloadducts in further transformations. The sulfinyl group, in the case of (S)-2-p-tolylsulfinyl-3-methyl-1,4-benzoquinone, failed to control diastereoselectivity in Diels-Alder reaction with cyclopentadiene and cyclohexadiene. Studies concerning the addition of ethyl acetate lithium enolate to the carbonyl groups of 2-methylsulfinyl-2-sulfanyl-cyclohexanones were also undertaken. In the case of 2-methylsulfinyl-2-methylsulfanylcyclohexanone, a mixture of conformers was evidenced by I. R. spectroscopy. On the basis of theoretical considerations, it could be advanced that, in the most abundant conformer, the SOCH3 and SCH3 groups lie, respectively, in equatorial and axial arrangements. Therefore, the observed enantiomeric excess can be explained considering that the enolate performs an axial attack to the carbonyl groups of the ketone conformers.

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