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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Investigation of Nanoparticles for Use in Microwave Systems in Biomedicine

Taghavi, Houra 03 October 2013 (has links)
This research focuses on the microwave properties of nanoparticles for use as contrast and hyperthermia agents. Currently, visible light is used for irradiation of nanoparticles as hyperthermia agents. Additionally, visible/Near-infrared light is used for photoacoustic tomography (PAT) imaging. Compared to optical wavelengths, frequencies in microwave range transmit through tissue with high penetration depth . Thus, deep cancerous cells and malignant tissue may be treated and imaged. These nanoparticles could enable the use of a hybrid microwave/acoustic technique known as thermoacoustic tomography. Here, quantitative measurements of the heat generation in super paramagnetic iron oxide nanoparticle (SPIONs), gold nanoparticles (AuNPs), and gold nanoclusters (AuNCs) induced by microwave energy at 3 GHz, are presented and compared. Based on our experiments, SPIONs are the most efficient nanoparticles for microwave heating. Very high concentrations of SPIONs are able to convert microwave energy into heat about 22° C more than DI-water. AuNPs, which support plasmon resonances, do not provide heat under microwave irradiation as predicted by our computational analysis based on Mie Theory. AuNCs are a new form of ultra-small (<2.5 nm) AuNPs which do not support plasmonic resonances and have supra-molecular properties such as sub-conduction band transitions. Interestingly, AuNCs have the potential to absorb microwave energy and may provide an alternative to SPIONs. These nanoparticles had not yet been studied before in this frequency region. In addition, the absorption coefficient of nanoparticles were calculated using complex permittivity data from a dip probe kit and a Vector Network Analyzer (VNA) in a broad band range from 500 MHZ to 10 GHz. This method allows identification of best frequency region with highest penetration depth. In the last step, the nanoparticles with different concentrations were tested as exogenous contrast agents in a Thermoacoustic Tomography (TAT) system. TAT utilizes the penetration depth of microwave energy while producing high resolution images through acoustic waves. The addition of an exogenous contrast agent improves image quality by more effectively converting microwave energy to heat. The experiment reveals that the time resolved thermoacoustic signal (TA) from SPIONs is stronger than AuNPs and AuNCs and thus, the image contrast produced by SPIONs is stronger than the two other aforementioned nanoparticles.
12

PURIFICAÇÃO DE NANOTUBOS DE CARBONO

Seixas, André Luís da Rosa 30 March 2010 (has links)
Submitted by MARCIA ROVADOSCHI (marciar@unifra.br) on 2018-08-14T19:33:27Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_AndreLuisDaRosaSeixas.pdf: 3229232 bytes, checksum: 35b1061853e1cce25d7bad1657766eaa (MD5) / Made available in DSpace on 2018-08-14T19:33:27Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_AndreLuisDaRosaSeixas.pdf: 3229232 bytes, checksum: 35b1061853e1cce25d7bad1657766eaa (MD5) Previous issue date: 2010-03-30 / Carbon Nanotubes (CNT) are obtained by the folding of one or many graphene leaves, in nanometric dimensions resulting in one tube of simple walls (SWNTC) or multiple walls (MWNTC). The electric, magnetic, optic and mechanic properties make the carbon nanotubes more fascinating and attractive to many applications, mainly in the nanotechnology area. In the synthesis process, with the NTCs formed, there are catalyst residues, soot and fullerenes. Thus, this paper had as aim to evaluate the NTC purification process, using oxidation with nitric and chloride acids (concentrated and diluted) with heating by microwave. In each 100mg sample, they were added 6mL of acid, in quartz tubes. After, the samples were irradiated for 0,10,20,40 and 60 minutes, in a 1400W potency (Multiwave 3000®, Paar, Graz, Austria). In the final solutions, nickel and lanthanum were determined by the spectrometry technique of optical emission with inductively coupled plasma (ICPOES). In order to evaluate the carbonacea impurity elimination and the NTCs integrity, it was used the Raman spectroscopy technique, gravimetric thermal analysis, transmission electronic microscopy and scanning electronic microscopy. Better La and Ni extraction were obtained when it was used HNO3, concentrated with 10 minutes irradiation, eliminating the carbonacea impurities without commitment in the NTC structure. / Nanotubos de Carbono (NTC) são obtidos pelo enrolamento de uma ou várias folhas do grafeno, em dimensões nanométricas formando um tubo de paredes simples (SWNTC) ou de parede múltiplas (MWNTC). As propriedades elétricas, magnéticas, ópticas e mecânicas fazem dos nanotubos de carbono materiais fascinantes e atrativos para muitas aplicações, principalmente no campo da nanotecnologia. No processo de síntese, junto aos NTC formados, encontram-se resíduos de catalisador, fuligem e fulerenos. Assim, este trabalho teve por objetivo avaliar procedimento de purificação de NTC, utilizando oxidação com ácido nítrico e clorídrico (concentrados e diluídos) com aquecimento por irradiação com micro-ondas. A cada 100 mg de amostra foram adicionados 6 mL de ácido, em tubos de quartzo. Após, as amostras foram irradiadas por 0, 10, 20, 40 e 60 minutos, numa potência de 1400W (Multiwave 3000®, Anton Paar, Graz, Áustria). Nas soluções finais, níquel e lantânio foram determinados pela técnica de espectrometria de emissão óptica com plasma indutivamente acoplado (ICP-OES). Para avaliar a eliminação das impurezas carbonáceas e integridade dos NTC utilizou-se as técnicas de espectroscopia Raman, análise térmica gravimétrica, microscopia eletrônica de transmissão e microscopia eletrônica de varredura. Melhores extrações de Ni e La foram obtidas quando se utilizou HNO3 concentrado com 10 minutos de irradiação, eliminando as impurezas carbonáceas sem comprometimento na estrutura do NTC.
13

Preparation and characterization of some ionic liquids and their use in the dimerization reaction of 2-methylpropene

Kärkkäinen, J. (Johanna) 27 February 2007 (has links)
Abstract This study concentrates on the preparation and characterization of some ionic liquids and their use in dimerization reaction of 2-methylpropene. Ionic liquids consist of cations and anions, and are commonly understood as green solvents. By definition their melting points should be lower than 100 °C. Prepared ionic liquids were used as catalytic solvents in dimerizations of 2-methylpropene to a high octane compound, isooctene. The monograph consists of two parts: the literature survey and the practical work. The literature survey reviews the preparation and characterization of ionic liquids as well as their environmental aspects, such as toxicity, biodegradability and recyclability. In addition, the acid catalyzed dimerization of butenes is discussed together with the dimerizations of light olefins carried out in ionic liquids. The practical work consists of three entities: The environmentally benign preparation of 1-alkyl-3-methylimidazolium-based ionic liquids under microwave activation, the characterization of ionic liquids and the use of the ionic liquids in the dimerization reaction. Ionic liquids absorb efficiently microwave irradiation and the most beneficial aspect in the microwave-assisted preparations was the considerably shortened reaction time compared to the conventional methods. In addition to the microwave-assisted preparations, [Cnmim][InCl4] ionic liquids were prepared successfully without microwave irradiation. A special attention was paid to the characterization of ionic liquids since impurities are known to affect on the properties of the ionic liquids. Ionic liquids were analysed with the following methods: 1H and 13C NMR, MS(ESI+ and ESI-), GC and elemental analysis. Characterization of ionic liquids was done by determining the thermal stability, the melting point and the crystal structure of each solid ionic liquid. The determination of the liquid range of ionic liquid is necessary in order to know the temperature limits for each ionic liquid. Novel InCl3-based ionic liquids revealed to be the more efficient than Brønsted acidic ILs as a catalytic reaction media in the dimerization of 2-methylpropene. It was preferable to apply [C6mim]Cl/InCl3 (x(InCl3) = 0.55) as a catalytic IL since then the conversion of 2-methylpropene and the product distribution revealed to be good. In order to maximize the production and the separation of dimers reaction should be carried out continuously at temperature high enough, such as 160 °C. Neutral InCl3-based ionic liquid did not catalyze reaction of 2-methylpropene, but it had to be acidic x(InCl3) > 0.5. Excess of InCl3 did not leach out from the IL and the recycling of IL was possible.
14

A Novel Collagen Extraction Method Based on Microwave Irradiation

Cheng, Yulin, Wu, Jiacheng, Zhang, Jinwei, Chen, Wuyong 26 June 2019 (has links)
Content: Microwave was used as a thermal source to extract collagen acid from the cattle hide in the present work. The effects of microwave on collagen extraction yields were studied under different microwave temperatures, time and hide-liquid ratio. The optimal extraction process was obtained by an orthogonal experiment, and the composition, structure and properties of the extracted collagen were characterized by amino acid analysis, SDS-PAGE, FTIR, UV-Vis, CD, FL, and VP-DSC. The results showed that the extraction rate of collagen was positively correlated with temperature, time and hide-liquid ratio. Under the condition of 35 °C, 6 h and 1:30 of solid-liquid ratio, the extraction proportion of collagen extracted under microwave was the highest, reaching to 13.40 %. The extracted collagen was identified as type I collagen by Amino acid analysis, and the graphic pattern of SDS-PAGE, FTIR and UV-Vis showed that the extracted collagen was similar to the standard type I collagen. Also, the results suggest that the triple helical structure exists still in the extracted collagen. The transition from triple helix to random coil of the extracted collagen was 41 ℃. These results provide a scientific basis for microwave technology for the extraction of collagen. Take-Away: The results showed that the extraction rate of collagen was positively correlated with temperature, time and hide-liquid ratio. Under the condition of 35 °C, 6 h and 1:30 of solid-liquid ratio, the extraction proportion of collagen extracted under microwave was the highest, reaching to 13.40 %. The extracted collagen was identified as type I collagen by Amino acid analysis, and the graphic pattern of SDS-PAGE, FTIR and UV-Vis showed that the extracted collagen was similar to the standard type I collagen. Also, the results suggest that the triple helical structure exists still in the extracted collagen. The transition from triple helix to random coil of the extracted collagen was 41 ℃. These results provide a scientific basis for microwave technology for the extraction of collagen.
15

Controlled fabrication of osmium nanocrystals by electron, laser and microwave irradiation and characterisation by microfocus X-ray absorption spectroscopy

Pitto-Barry, Anaïs, Geraki, K., Horbury, M.D., Stavros, V.G., Mosselmans, J.F.W., Walton, R.I., Sadler, P.J., Barry, Nicolas P.E. 23 October 2017 (has links)
Yes / Osmium nanocrystals can be fabricated by electron (3–50 nm, formed by atom migration), 785–815 nm laser (20–50 nm, in micelle islands), and microwave (ca. 1 nm in arrays, >100 mg scale) irradiation of a polymer-encapsulated OsII carborane; microfocus X-ray absorption studies at the Os LIII-edge show differences between the three preparation methods, suggesting that the electron-beam irradiated materials have a significant support interaction and/or surface oxidation, while the laser and microwave samples are more like metallic osmium. / Royal Society (University Research Fellowship No. UF150295 to NPEB), the Leverhulme Trust (Early Career Fellowship No. ECF-2013-414 to NPEB), the ERC (Grant No. 247450 to PJS), EPSRC (Grant No. EP/F034210/1 to PJS and EP/ J007153/1 to VGS), Diamond Light Source (Beam-time grant number SP11314).
16

Carbohydrate-Functionalized Nanomaterials : Synthesis, Characterization and Biorecognition Studies

Kong, Na January 2015 (has links)
This thesis focuses on the development of carbohydrate coupling chemistry on nanomaterials and their biological activity studies. It is divided into two parts: In part one, two carbohydrate immobilization approaches, based on perfluorophenyl azide (PFPA)-functionalized silica nanoparticles (SNPs), are presented, where the binding affinity of the glyconanoparticles was evaluated through carbohydrate-lectin interaction. In the first approach, PFPAfunctionalized SNPs were treated with propargylated glycosides and functionalized under copper-catalyzed azide-alkyne cycloaddition (CuAAC) conditions to give glyconanoparticles. For the second approach, a metal-free coupling chemistry based on perfluorophenyl azide-aldehyde-amine cycloaddition (AAAC) was developed for carbohydrate immobilization on PFPA-functionalized SNPs using glycosyl amine and phenylacetaldehyde. Subsequently, a quantitative fluorine nuclear magnetic resonance (19F qNMR) technique was developed to determine the carbohydrate density on the glyconanoparticles. The addition of an internal standard allowed the accurate determination of carbohydrate density, which was then used to calculate the apparent dissociation constant (Kd ) of the glyconanoparticles with lectin by a ligand competition assay. The developed approaches proved general and versatile, and the carbohydrate-presenting nanoplatforms showed high binding specificity in lectin binding. In part two, microwave irradiation was used to functionalize carbon nanomaterials with PFPA followed by carbohydrate conjugation. The microwave-assisted method proved efficient for a number of carbon nanomaterials including carbon nanotubes (CNTs), graphene and fullerene. The carbohydrates on the glyconanomaterials retained their binding patterns towards cognate lectins. / <p>QC 20150907</p>
17

Aplicação da irradiação micro-ondas em biocatálise: resolução cinética, redução de cetonas e adição de Michael / Application of microwave irradiation on biocatalysis: kinetic resolution, reduction of ketones and Michael addition

Ribeiro, Sandra Santos 13 June 2014 (has links)
Neste trabalho foram realizadas reações de resolução enzimática de ciano-hidrinas [(±)-mandelonitrila 1a, (±)-2-(4-clorofenil)-2-hidroxiacetonitrila 2a, (±)-2-hidroxi-2-(4- hidroxifenil)acetonitrila 3a, (±)-2-hidroxibutanonitrila 4a, (±)-2-(4- fluorofenil)acetonitrila 5a, (±)-2-hidroxi-2-(4-metoxifenil)acetonitrila 6a, (±)-2-hidroxi- 2-(3-fenoxifenil)acetonitrila 7a e (±)-(E)-2-hidroxi-4-fenilbut-3-enonitrila 8a] e de álcoois organofluorados [(±)-2,2,2-trifluoro-1-feniletanol ±9a, ±±)-1-(2,4,5- trifluorofenil)etanol 10a, (±)-1-(3-bromofenil)-2,2,2-trifluoroetanol 11a, (±)-1-(4- bromofenil)-2,2,2-trifluoroetanol 12a e (±)-1-(2-trifluorometil)feniletanol 13a] utilizando a lipase imobilizada de Candida antarctica (CALB). As reações foram realizadas em agitador orbital por um período de tempo que variou entre 24-168 h de reação apresentando diferentes conversões e excessos enantioméricos: [(R)-álcool 1a (c = 51%, ee = 51%), (S)-acetato 1b (c = 49%, ee = 98%); (R)-álcool 2a (c = 42%, ee > 99%), (S)-acetato 2b (c = 58%, ee = 94%); (R)-álcool 3a (c = 34%), (S)-acetato 3b (c = 32%, ee = 28%); (R)-álcool 4a (c = 82%), (S)-acetato 4b (c = 18%, ee = 25%); (R)-álcool 5a (c = 5%), (S)-acetato 5b (c = 55%, ee = 97%); (R)-álcool 6a (c = 44%), (S)-acetato 6b (c = 56%, ee = 99%); (R)-álcool 7a (c = 53%), (S)-acetato 7b (c = 47%, ee = 92%); (R)-álcool 8a (c = 40%), (S)-acetato 8b (c = 60%, ee = 80%); (R)-álcool 9a (c = 51%, ee = 62%), (S)- acetato 9b (c = 49%, ee > 99%); (S)-álcool 10a (c = 50%, ee > 99%), (R)-acetato 10b (c = 50%, ee > 99%); (R)-álcool 11a (c = 49%, ee = 61%), (S)-acetato 11b (c = 51%, ee = 82%); (R)-álcool 12a (c = 51%, ee = 72%), (S)-acetato 12b (c = 49%, ee > 99%); (S)-álcool 13a (c = 88%), (R)-acetato 13b (c = 12%, ee > 99). Os resultados por irradiação micro-ondas para os compostos obtidos apresentaram menores tempos de reação (1-14 h) comprovando a sua eficiência na resolução quimio-enzimática de compostos organofluorados e ciano-hidrinas: [(R)-álcool 1a (c = 60%, ee = 89%), (S)-acetato 1b (c = 40%, ee = 92%); (R)-álcool 2a (c = 47%, ee = 82%), (S)-acetato 2b (c = 53%, ee = 90%); (R)-álcool 3a (c = 34%), (S)-acetato 3b (c = 17%, ee = 59%); (R)-álcool 5a (c = 4%, ee = 88%), (S)-acetato 5b (c = 50%, ee = 92%); (R)-álcool 6a (c = 44%, ee = 73%), (S)-acetato 6b (c = 56%, ee = 90%); (R)-álcool 7a (c = 50%, ee = 84%), (S)-acetato 7b (c = 50%, ee = 84%); (R)-álcool 8a (c = 41%, ee = 91%), (S)-acetato 8b (c = 59%, ee = 74%); (S)-álcool 9a (c = 95%), (R)-acetato 9b (c = 5%, ee > 99%); (R)-álcool 10a (c = 50%, ee >99%), (S)- acetato 10b (c = 50%, ee >99%); (R)-álcool 11a (c = 58%, ee = 43%), (S)-acetato 11b (c = 42%, ee = 78%); (S)-álcool 12a (c = 51%, ee = 70%), (R)-acetato 12b (c = 49%, ee = 98%); (S)-álcool 13a (c = 85%), (R)-acetato 13b (c = 15%, ee > 99)]. Em especial destaca-se, neste trabalho o uso de células microbianas utilizando a irradiação micro-ondas na redução de fluorocetonas. Sendo assim, foi realizada reações de biorredução da (±)- 2,2,2-trifluoroacetofenona 3 em agitador orbital e irradiação micro-ondas pelo fungo marinho Mucor racemosus CBMAI 847 nas concentrações de (2,9; 5,7; 8,5 e 14 mmol/L) em pH 8 e na concentração de 14 mmol/L em pH 5. Após 6 h de reação obtiveram-se conversões entre 39-100% e excessos enantioméricos entre 74-96% em agitador orbital e por irradiação micro-ondas obteve-se uma variação de 28-64% de conversão e excesso enantiomérico entre 73-96%. Também foram realizadas reações de biorredução com as bactérias termofílicas SPZSP005, SPZSP088, SPZSP051 e SPZSP055 para cetonas organofluoradas obtendo-se elevadas enantiosseletividades (>99%) e conversões (>99%). Esse estudo relata a primeira investigação da literatura frente ao uso de fungo e bactérias termofílicas por irradiação micro-ondas aplicada em biocatálise. Foram também realizadas reações de adição de aza-Michael entre a benzilamina e cetonas ?,&beta;-insaturadas (ciclo-hexenona, 3-metil-2-ciclo-hexen-1-ona e a 2,5-dimetil-para-benzoquinona) utilizando a CALB em diferentes solventes orgânicos (EtOAc, CH2Cl2, n-hexano, MeOH, tolueno, éter etílico e THF) em agitador orbital e por irradiação micro-ondas. Através das reações de adição de aza-Michael foi obtido por adição-1,2 e adição-1,4 como adutos iminas, os quais foram caracterizadas por espectrometria de massas. Finalmente neste trabalho aplicou a irradiação micro-ondas em biocatálise via resolução cinética, redução de cetonas e adição de Michael. / In this study, enzymatic kinetic resolutions of cyanohydrins [(±)-mandelonitrile 1a, (±)-2-(4-chlorophenyl)-2-hydroxyacetonitrile 2a, (±)-2-hydroxy-2-(4- hydroxyphenyl)acetonitrile 3a, (±)-2-hydroxybutanenitrile 4a, (±)-2-(4- fluorophenyl)acetonitrile 5a, (±)-2-hydroxy-2-(4-metoxiphenyl)acetonitrile 6a, (±)-2- hydroxy-2-(3-fenoxyphenyl)acetonitrile 7a and (±)-(E)-2-hydroxy-4-phenylbut-3- enonitrile 8a], and organofluorine alcohols [(±)-2,2,2-trifluoro-1-phenylethanol 9a, (±)-1-(2,4,5-trifluorophenyl)ethanol 10a, (±)-1-(3-bromophenyl)-2,2,2-trifluoroethanol 11a, (±)-1-(4-bromophenyl)-2,2,2-trifluoroethanol 12a and (±)-1-(2- trifluoromethyl)phenylethanol 13a] were performed using immobilized lipase from Candida Antarctica (CALB). The reactions were performed on an orbital shaking for a period ranging from 24 to 168 h with different conversions and enantiomeric excesses. [(R)- alcohol 1a (c = 51%, ee = 51%), (S)-acetate 1b (c = 49%, ee = 98%); (R)- alcohol 2a (c = 42%, ee > 99%), (S)-acetate 2b (c = 58%, ee = 94%); (R)-alcohol 3a (c = 34%), (S)-acetate 3b (c = 32%, ee = 28%); (R)-alcohol 4a (c = 82%), (S)-acetate 4b (c = 18%, ee = 25%); R)-alcohol 5a (c = 5%), (S)-acetate 5b (c = 55%, ee = 97%); (R)-alcohol 6a (c = 44%), (S)-acetate 6b (c = 56%, ee = 99%); (R)-alcohol 7a (c = 53%), (S)-acetate 7b (c = 47%, ee = 92%); (R)-alcohol 8a (c = 40%), (S)-acetate 8b (c = 60%, ee = 80%); (R)- alcohol 9a (c = 51%, ee = 62%), (S)-acetate 9b (c = 49%, ee > 99%); (S)-alcohol 10a (c = 50%, ee > 99%), (R)-acetate 10b (c = 50%, ee > 99%); (R)-alcohol 11a (c = 49%, ee = 61%), (S)-acetate 11b (c = 51%, ee = 82%); (R)-alcohol 12a (c = 51%, ee = 72%), (S)- acetate 12b (c = 49%, ee > 99%); (S)-alcohol 13a (c = 88%), (R)-acetate 13b (c = 12%, ee > 99). The results obtained by microwave irradiation for the substrates showed shorter reaction times (1 to 14 h) demonstrating its efficiency in chemoenzymatic esterifications of organofluorine compounds and cyanohydrins [(R)-alcohol 1a (c = 60%, ee = 89%), (S)-acetate 1b (c = 40%, ee = 92%); (R)-alcohol 2a (c = 47%, ee = 82%), (S)-acetate 2b (c = 53%, ee = 90%); (R)-alcohol 3a (c = 34%), (S)-acetate 3b (c = 17%, ee = 59%); (R)-alcohol 5a (c = 4%, ee = 88%), (S)-acetate 5b (c = 50%, ee = 92%); (R)-alcohol 6a (c = 44%, ee = 73%), (S)-acetate 6b (c = 56%, ee = 90%); (R)-alcohol 7a (c = 50%, ee = 84%), (S)-acetate 7b (c = 50%, ee = 84%); (R)-alcohol 8a (c = 41%, ee = 91%), (S)-acetate 8b (c = 59%, ee = 74%); (S)-alcohol 9a (c = 95%), (R)-acetate 9b (c = 5%, ee > 99%); (R)- alcohol 10a (c = 50%, ee >99%), (S)-acetate 10b (c = 50%, ee >99%); (R)-alcohol 11a (c = 58%, ee = 43%), (S)-acetate 11b (c = 42%, ee= 78%); (S)-alcohol 12a (c = 51%, ee = 70%), (R)-acetate 12b (c = 49%, ee = 98%); (S)-alcohol 13a (c = 85%), (R)-acetate 13b (c = 15%, ee > 99)]. In particular, this thesis show the use of microbial cells in reduction of fluoroketones by microwave irradiation. Thus, bioreduction reactions of (±)-2,2,2- trifluoroacetophenone 3 was performed in orbital shaking and microwave irradiation by marine fungus Mucor racemosus CBMAI 847 in different concentrations (2.9, 5.7, 8.5 and 14 mmol/L) at pH 8 and in the concentration of 14 mmol/L at pH 5. In the reactions after 6 h were obtained a conversion of 39 to 100% and enantiomeric excess of 74-96%, in orbital shaking. The reaction on microwave irradiation gave an increase conversion of 28-64% and enantiomeric excess of 73-96%. Bioreduction reactions were also performed with the thermophilic bacteria SPZSP005, SPZSP088, SPZSP051 and SPZSP055 for organofluorine ketones obtaining high enantioselectivities (> 99%) and conversions (> 99%). This study describes the first investigation on the literature regarding the use of thermophilic bacteria and fungus by microwave irradiation applied to biocatalysis. Were also carried out reactions of aza-Michael addition of benzylamine and ?, &beta;-unsaturated cyclohexenones (cyclo- hexenone, 3-methyl-2-cyclo-hexen-1-one and 2,5-dimethyl-para-benzoquinone) were investigated, using CALB in different organic solvents (EtOAc, CH2Cl2, n-hexane, MeOH, toluene, ethylic ether and THF) in orbital shaking and microwave irradiation. From aza-Michael addition reactions was possible to obtain by 1,2- and 1,4-adition the adduct imines, which were characterized by mass spectrometry. Finally this thesis applied the microwave irradiation in biocatalysis via kinetic resolution, reduction of ketones and aza-Michael addition.
18

Aplicação da irradiação micro-ondas em biocatálise: resolução cinética, redução de cetonas e adição de Michael / Application of microwave irradiation on biocatalysis: kinetic resolution, reduction of ketones and Michael addition

Sandra Santos Ribeiro 13 June 2014 (has links)
Neste trabalho foram realizadas reações de resolução enzimática de ciano-hidrinas [(±)-mandelonitrila 1a, (±)-2-(4-clorofenil)-2-hidroxiacetonitrila 2a, (±)-2-hidroxi-2-(4- hidroxifenil)acetonitrila 3a, (±)-2-hidroxibutanonitrila 4a, (±)-2-(4- fluorofenil)acetonitrila 5a, (±)-2-hidroxi-2-(4-metoxifenil)acetonitrila 6a, (±)-2-hidroxi- 2-(3-fenoxifenil)acetonitrila 7a e (±)-(E)-2-hidroxi-4-fenilbut-3-enonitrila 8a] e de álcoois organofluorados [(±)-2,2,2-trifluoro-1-feniletanol ±9a, ±±)-1-(2,4,5- trifluorofenil)etanol 10a, (±)-1-(3-bromofenil)-2,2,2-trifluoroetanol 11a, (±)-1-(4- bromofenil)-2,2,2-trifluoroetanol 12a e (±)-1-(2-trifluorometil)feniletanol 13a] utilizando a lipase imobilizada de Candida antarctica (CALB). As reações foram realizadas em agitador orbital por um período de tempo que variou entre 24-168 h de reação apresentando diferentes conversões e excessos enantioméricos: [(R)-álcool 1a (c = 51%, ee = 51%), (S)-acetato 1b (c = 49%, ee = 98%); (R)-álcool 2a (c = 42%, ee > 99%), (S)-acetato 2b (c = 58%, ee = 94%); (R)-álcool 3a (c = 34%), (S)-acetato 3b (c = 32%, ee = 28%); (R)-álcool 4a (c = 82%), (S)-acetato 4b (c = 18%, ee = 25%); (R)-álcool 5a (c = 5%), (S)-acetato 5b (c = 55%, ee = 97%); (R)-álcool 6a (c = 44%), (S)-acetato 6b (c = 56%, ee = 99%); (R)-álcool 7a (c = 53%), (S)-acetato 7b (c = 47%, ee = 92%); (R)-álcool 8a (c = 40%), (S)-acetato 8b (c = 60%, ee = 80%); (R)-álcool 9a (c = 51%, ee = 62%), (S)- acetato 9b (c = 49%, ee > 99%); (S)-álcool 10a (c = 50%, ee > 99%), (R)-acetato 10b (c = 50%, ee > 99%); (R)-álcool 11a (c = 49%, ee = 61%), (S)-acetato 11b (c = 51%, ee = 82%); (R)-álcool 12a (c = 51%, ee = 72%), (S)-acetato 12b (c = 49%, ee > 99%); (S)-álcool 13a (c = 88%), (R)-acetato 13b (c = 12%, ee > 99). Os resultados por irradiação micro-ondas para os compostos obtidos apresentaram menores tempos de reação (1-14 h) comprovando a sua eficiência na resolução quimio-enzimática de compostos organofluorados e ciano-hidrinas: [(R)-álcool 1a (c = 60%, ee = 89%), (S)-acetato 1b (c = 40%, ee = 92%); (R)-álcool 2a (c = 47%, ee = 82%), (S)-acetato 2b (c = 53%, ee = 90%); (R)-álcool 3a (c = 34%), (S)-acetato 3b (c = 17%, ee = 59%); (R)-álcool 5a (c = 4%, ee = 88%), (S)-acetato 5b (c = 50%, ee = 92%); (R)-álcool 6a (c = 44%, ee = 73%), (S)-acetato 6b (c = 56%, ee = 90%); (R)-álcool 7a (c = 50%, ee = 84%), (S)-acetato 7b (c = 50%, ee = 84%); (R)-álcool 8a (c = 41%, ee = 91%), (S)-acetato 8b (c = 59%, ee = 74%); (S)-álcool 9a (c = 95%), (R)-acetato 9b (c = 5%, ee > 99%); (R)-álcool 10a (c = 50%, ee >99%), (S)- acetato 10b (c = 50%, ee >99%); (R)-álcool 11a (c = 58%, ee = 43%), (S)-acetato 11b (c = 42%, ee = 78%); (S)-álcool 12a (c = 51%, ee = 70%), (R)-acetato 12b (c = 49%, ee = 98%); (S)-álcool 13a (c = 85%), (R)-acetato 13b (c = 15%, ee > 99)]. Em especial destaca-se, neste trabalho o uso de células microbianas utilizando a irradiação micro-ondas na redução de fluorocetonas. Sendo assim, foi realizada reações de biorredução da (±)- 2,2,2-trifluoroacetofenona 3 em agitador orbital e irradiação micro-ondas pelo fungo marinho Mucor racemosus CBMAI 847 nas concentrações de (2,9; 5,7; 8,5 e 14 mmol/L) em pH 8 e na concentração de 14 mmol/L em pH 5. Após 6 h de reação obtiveram-se conversões entre 39-100% e excessos enantioméricos entre 74-96% em agitador orbital e por irradiação micro-ondas obteve-se uma variação de 28-64% de conversão e excesso enantiomérico entre 73-96%. Também foram realizadas reações de biorredução com as bactérias termofílicas SPZSP005, SPZSP088, SPZSP051 e SPZSP055 para cetonas organofluoradas obtendo-se elevadas enantiosseletividades (>99%) e conversões (>99%). Esse estudo relata a primeira investigação da literatura frente ao uso de fungo e bactérias termofílicas por irradiação micro-ondas aplicada em biocatálise. Foram também realizadas reações de adição de aza-Michael entre a benzilamina e cetonas ?,&beta;-insaturadas (ciclo-hexenona, 3-metil-2-ciclo-hexen-1-ona e a 2,5-dimetil-para-benzoquinona) utilizando a CALB em diferentes solventes orgânicos (EtOAc, CH2Cl2, n-hexano, MeOH, tolueno, éter etílico e THF) em agitador orbital e por irradiação micro-ondas. Através das reações de adição de aza-Michael foi obtido por adição-1,2 e adição-1,4 como adutos iminas, os quais foram caracterizadas por espectrometria de massas. Finalmente neste trabalho aplicou a irradiação micro-ondas em biocatálise via resolução cinética, redução de cetonas e adição de Michael. / In this study, enzymatic kinetic resolutions of cyanohydrins [(±)-mandelonitrile 1a, (±)-2-(4-chlorophenyl)-2-hydroxyacetonitrile 2a, (±)-2-hydroxy-2-(4- hydroxyphenyl)acetonitrile 3a, (±)-2-hydroxybutanenitrile 4a, (±)-2-(4- fluorophenyl)acetonitrile 5a, (±)-2-hydroxy-2-(4-metoxiphenyl)acetonitrile 6a, (±)-2- hydroxy-2-(3-fenoxyphenyl)acetonitrile 7a and (±)-(E)-2-hydroxy-4-phenylbut-3- enonitrile 8a], and organofluorine alcohols [(±)-2,2,2-trifluoro-1-phenylethanol 9a, (±)-1-(2,4,5-trifluorophenyl)ethanol 10a, (±)-1-(3-bromophenyl)-2,2,2-trifluoroethanol 11a, (±)-1-(4-bromophenyl)-2,2,2-trifluoroethanol 12a and (±)-1-(2- trifluoromethyl)phenylethanol 13a] were performed using immobilized lipase from Candida Antarctica (CALB). The reactions were performed on an orbital shaking for a period ranging from 24 to 168 h with different conversions and enantiomeric excesses. [(R)- alcohol 1a (c = 51%, ee = 51%), (S)-acetate 1b (c = 49%, ee = 98%); (R)- alcohol 2a (c = 42%, ee > 99%), (S)-acetate 2b (c = 58%, ee = 94%); (R)-alcohol 3a (c = 34%), (S)-acetate 3b (c = 32%, ee = 28%); (R)-alcohol 4a (c = 82%), (S)-acetate 4b (c = 18%, ee = 25%); R)-alcohol 5a (c = 5%), (S)-acetate 5b (c = 55%, ee = 97%); (R)-alcohol 6a (c = 44%), (S)-acetate 6b (c = 56%, ee = 99%); (R)-alcohol 7a (c = 53%), (S)-acetate 7b (c = 47%, ee = 92%); (R)-alcohol 8a (c = 40%), (S)-acetate 8b (c = 60%, ee = 80%); (R)- alcohol 9a (c = 51%, ee = 62%), (S)-acetate 9b (c = 49%, ee > 99%); (S)-alcohol 10a (c = 50%, ee > 99%), (R)-acetate 10b (c = 50%, ee > 99%); (R)-alcohol 11a (c = 49%, ee = 61%), (S)-acetate 11b (c = 51%, ee = 82%); (R)-alcohol 12a (c = 51%, ee = 72%), (S)- acetate 12b (c = 49%, ee > 99%); (S)-alcohol 13a (c = 88%), (R)-acetate 13b (c = 12%, ee > 99). The results obtained by microwave irradiation for the substrates showed shorter reaction times (1 to 14 h) demonstrating its efficiency in chemoenzymatic esterifications of organofluorine compounds and cyanohydrins [(R)-alcohol 1a (c = 60%, ee = 89%), (S)-acetate 1b (c = 40%, ee = 92%); (R)-alcohol 2a (c = 47%, ee = 82%), (S)-acetate 2b (c = 53%, ee = 90%); (R)-alcohol 3a (c = 34%), (S)-acetate 3b (c = 17%, ee = 59%); (R)-alcohol 5a (c = 4%, ee = 88%), (S)-acetate 5b (c = 50%, ee = 92%); (R)-alcohol 6a (c = 44%, ee = 73%), (S)-acetate 6b (c = 56%, ee = 90%); (R)-alcohol 7a (c = 50%, ee = 84%), (S)-acetate 7b (c = 50%, ee = 84%); (R)-alcohol 8a (c = 41%, ee = 91%), (S)-acetate 8b (c = 59%, ee = 74%); (S)-alcohol 9a (c = 95%), (R)-acetate 9b (c = 5%, ee > 99%); (R)- alcohol 10a (c = 50%, ee >99%), (S)-acetate 10b (c = 50%, ee >99%); (R)-alcohol 11a (c = 58%, ee = 43%), (S)-acetate 11b (c = 42%, ee= 78%); (S)-alcohol 12a (c = 51%, ee = 70%), (R)-acetate 12b (c = 49%, ee = 98%); (S)-alcohol 13a (c = 85%), (R)-acetate 13b (c = 15%, ee > 99)]. In particular, this thesis show the use of microbial cells in reduction of fluoroketones by microwave irradiation. Thus, bioreduction reactions of (±)-2,2,2- trifluoroacetophenone 3 was performed in orbital shaking and microwave irradiation by marine fungus Mucor racemosus CBMAI 847 in different concentrations (2.9, 5.7, 8.5 and 14 mmol/L) at pH 8 and in the concentration of 14 mmol/L at pH 5. In the reactions after 6 h were obtained a conversion of 39 to 100% and enantiomeric excess of 74-96%, in orbital shaking. The reaction on microwave irradiation gave an increase conversion of 28-64% and enantiomeric excess of 73-96%. Bioreduction reactions were also performed with the thermophilic bacteria SPZSP005, SPZSP088, SPZSP051 and SPZSP055 for organofluorine ketones obtaining high enantioselectivities (> 99%) and conversions (> 99%). This study describes the first investigation on the literature regarding the use of thermophilic bacteria and fungus by microwave irradiation applied to biocatalysis. Were also carried out reactions of aza-Michael addition of benzylamine and ?, &beta;-unsaturated cyclohexenones (cyclo- hexenone, 3-methyl-2-cyclo-hexen-1-one and 2,5-dimethyl-para-benzoquinone) were investigated, using CALB in different organic solvents (EtOAc, CH2Cl2, n-hexane, MeOH, toluene, ethylic ether and THF) in orbital shaking and microwave irradiation. From aza-Michael addition reactions was possible to obtain by 1,2- and 1,4-adition the adduct imines, which were characterized by mass spectrometry. Finally this thesis applied the microwave irradiation in biocatalysis via kinetic resolution, reduction of ketones and aza-Michael addition.
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Processamento de hidroxiapatita por microondas: sÃntese de pÃs e sinterizaÃÃo de peÃas / Processing of hydroxyapatite by microwave irradiation: synthesis of powder and sintering of parts

Eden Batista Duarte 22 December 2009 (has links)
FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / As biocerÃmicas sÃo substÃncias ou combinaÃÃo de substÃncias que tem aplicabilidade clÃnica, com a finalidade de restituir ou tratar ÃrgÃos, tecidos ou funÃÃes do corpo humano. SÃo quimicamente muito estÃveis e, portanto, pouco provÃveis de induzir uma resposta biolÃgica adversa. As biocerÃmicas mais empregadas na reconstituiÃÃo de tecidos sÃo à base de fosfato de cÃlcio, com razÃo Ca/P que varia de 0,5 a 2,0; formando diferentes fases, dentre as quais a mais estudada à a hidroxiapatita, cuja composiÃÃo quÃmica à semelhante à fase inorgÃnica dos ossos e dentes. A hidroxiapatita pode ser obtida atravÃs de diferentes mecanismos em fase sÃlida ou via Ãmida. Neste estudo, foram obtidas biocerÃmicas de apatitas por meio de uma reaÃÃo em estado sÃlido via radiaÃÃo por microondas, utilizando os reagentes: hidrÃxido de cÃlcio [Ca(OH)2] e difosfato de cÃlcio (CaHPO4). Os pÃs obtidos foram submetidos a tratamentos tÃrmicos de 850ÂC e 1050ÂC e caracterizados por DifraÃÃo de Raios-x (DRX), Espectroscopia de Transformada de Fourier por Raios Infravermelhos (FTIR), FluorescÃncia de Raios-X (FRX), AnÃlise TermogravimÃtrica (ATG) e Microscopia EletrÃnica de Varredura (MEV). As fases predominantes foram identificadas como sendo hidroxiapatita e &#946;-fosfato tricÃlcio. Em seguida, os pÃs foram prensados unixialmente em molde cilÃndrico, com ligante, e sinterizados a 1200ÂC por 1 hora. A microestrutura final apresentou a fase cristalina hidroxiapatita (HA) / Bioceramic are substances or combination of substances which has some clinical applicability and can be used for treating or replacing any tissue, organ or function of the body. They are chemically stable and have almost no adverse biological effects. The most widely used bioceramics for tissue reconstitution are calcium phosphate based bioceramics having Ca/P ratio changing from 0.5 to 2.0, which leads to diferent phases. The most important phase is hydroxyapatite due to its chemical composition, which is similar to that of hard tissues. Hydroxyapatite can be obtained by different mechanisms such as wet methods and solid-state reactions. In this study, apatite bioceramics were obtained from solid-state reaction by Microwave Irradiation, using calcium phosphate (CaHPO4) and calcium hydroxide [Ca(OH)2]. The powders obtained were heat treated at 850ÂC and 1050ÂC and characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) Spectroscopy, Thermal Gravimetric Analysis (TGA) and Scanning Electron Microscope (SEM). The predominant phases identified were hydroxyapatite and &#946;-tricalcium phosphate. The powders were uniaxially pressed in cylindrical dyes and sintered at 1200ÂC for 1hour. Final microstructure presented the hydroxyapatite (HA) phase
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Síntese de 3-haloacetil-4-metilquinolinas utilizando líquido iônico sob irradiação de micro-ondas / Microwave-assisted synthesis of 3-haloacetyl-4- methylquinolines in ionic liquid

Prola, Liziê Daniela Tentler 27 July 2011 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / The synthesis of a series of 3-haloacetyl-4-methyl-quinolines from the cyclocondensation reaction of 4-alkoxyvinyl ketones [R1C(O)CH=C(R2)(OCH3), where R1 = CF3, CCl3, CHCl2, CF2Cl, CF2CF3 and R2 = Me, Et, Pr, Bu, i-Bu, i- Pent] with 2-aminoacetophenone is reported. The reaction was performed in the presence of p-toluene sulphonic acid (p-TsOH), ionic liquid ([HMIM][TsO]) and under microwave irradiation. The molar ratio of the reactants 4-alkoxyvinyl ketone and 2-aminoacetophenone was of 1:1, respectively, for the quinoline with R1 = CHCl2, while for the other reactions was necessary a molar ratio of 1.2:1, respectively. The results showed that the combination of ionic liquid and microwave irradiation was effective for this synthesis, since the products were obtained with short rteaction times (10-20 min) and high yields (70-91%). In addition, the advantages of using the microwave irradiation method in comparison to the conventional thermal heating were also demonstrated. / Neste trabalho é descrita a síntese de uma série de 3-haloacetil-4-metilquinolinas a partir da reação de ciclocondensação de 4-alcoxivinil cetonas [R1C(O)CH=C(R2)(OCH3), onde R1 = CF3, CCl3, CHCl2, CF2Cl, CF2CF3 e R2 = Me, Et, Pr, Bu, i-Bu, i-Pent] com 2-aminoacetofenona. As condições reacionais utilizadas para a obtenção dos compostos heterocíclicos foram realizadas na presença d6 ácido p-tolueno sulfônico (ac. p-TsOH) e líquido iônico ([HMIM][TsO]) sob irradiação de micro-ondas. A relação molar empregada da 4-alcoxivinil cetona e da 2-aminoacetofenona foi de 1:1, respectivamente, para a quinolina R1 = CHCl2, enquanto que para as outras reações foi necessário uma relação molar de 1,2:1. Os resultados obtidos demonstraram que a combinação de líquido iônico e irradiação de micro-ondas foram eficazes para essa síntese, já que os produtos foram obtidos em tempo reacionais curtos (10- 20 min) e altos rendimentos (70-91%). Além disso, também foram mostradas as vantagens do método de irradiação de micro-ondas sobre o método convencional de aquecimento.

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