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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.
1

Síntese de novas 4-acil-semicarbazidas e 1,2,4-triazóis isoxazolínicos com potenciais atividades biológicas

ARAÚJO NETA, Marlene Saraiva de 26 February 2014 (has links)
Submitted by Isaac Francisco de Souza Dias (isaac.souzadias@ufpe.br) on 2016-01-25T17:16:38Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DISSERTAÇÃO DE MESTRADO - MARLENE SARAIVA DE ARAÚJO NETA.pdf: 2177316 bytes, checksum: ba8286fc22cd5e5e207b9fa533be39e5 (MD5) / Made available in DSpace on 2016-01-25T17:16:38Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DISSERTAÇÃO DE MESTRADO - MARLENE SARAIVA DE ARAÚJO NETA.pdf: 2177316 bytes, checksum: ba8286fc22cd5e5e207b9fa533be39e5 (MD5) Previous issue date: 2014-02-26 / Na literatura, existem inúmeros trabalhos com moléculas que possuem o núcleo 2-isoxazolina, como também moléculas que possuem os núcleos 4-acil-semicarbazida e 1,2,4-triazol. Não apenas trabalhos químicos para síntese destes grupos, mas, trabalhos com atividades farmacológicas, como antifúngica, antimicrobiana, anticonvulsivante, antinociceptiva, dentre outras atividades são amplamente discutidas. Desta forma, 5 novos derivados hibridizados com os núcleos citados foram sintetizados, porém o 1,2,4-triazol isoxazolínico sofreu degradação. A rota sintética consiste primeiramente na síntese do núcleo 2-isoxazolina azabicíclica, que foi realizada em duas partes, a partir da cicloadição 1,3-dipolar de enercarbamatos e enamidas endocíclicas com o N-óxido de nitrila CEFNO. As enemidas e enecarbamatos foram sintetizados tanto pelo método convencional já utilizado no grupo de pesquisa como pelo método novo utilizando o aparelho de ultrasom. Os cicloadutos advindos da cicloadição com os enecarbamatos sofreram desproteção do N5 por hidrólise ácida com o ácido trifluoroacético ou hidrogenólise e em seguida ocorreu a reação de N-benzoilação. Na cicloadição com enamidas endocíclicas e o N-óxido de nitrila CEFNO algumas etapas são diminuídas e o produto obtido já é a isoxazolina azabicíclica N-benzoílada. Posteriormente, estes produtos reagem com a hidrazina 80%, formando as respectivas hidrazidas N- benzoíladas que sofrem uma reação de condensação com o isocianato de p-clorofenila formando as 4-acil-semicarbazidas isoxazolínicas. Por fim, a ciclização da 4-acil-semicarbazida em meio básico foi realizada formando o 1,2,4-triazol isoxazolínico azabicíclico. Todos os novos produtos foram identificados e caracterizados por meio de espectrometria do Infravermelho e espectroscopia do RMN de 1H e 13C Os testes biológicos, atividade antinociceptiva e antimicrobiana, das novas 4-acil-semicarbazidas e 1,2,4-triazol ficam como perspectiva deste trabalho. / In literature, there are numerous studies which have molecules with 2-isoxazoline core, as well as molecules possessing the 4-acyl semicarbazide cores and 1,2,4-triazole. Not only chemical works for synthesis of these groups, but works with pharmacological activities such as antifungal, antimicrobial, anticonvulsant, anti-nociceptive and other activities are widely discussed. Thus, five new derivatives hybridized with the above cores were synthesized, but the 1,2,4-triazole isoxazolínico suffered degradation. The first synthetic pathway consists in the synthesis of 2-isoxazoline core azabicyclic, which was performed in two parts from the 1,3-dipolar cycloaddition of enercarbamatos and enamides with the endocyclic N-oxide CEFNO nitrile. The enemidas and enecarbamates were synthesized by both the conventional method already used in the research group as the new method using the ultrasonic apparatus. The cicloadutos arising from cycloaddition with enecarbamates N5 underwent deprotection by the acid hydrolysis with trifluoroacetic acid or hydrogenolysis and then place the N-benzoylation reaction. In endocyclic cycloaddition with enamides and nitrile N-oxide CEFNO some steps are reduced and the product is already obtained the azabicyclic N-benzoylated isoxazoline. Subsequently, these products are reacted with 80% hydrazine to form the corresponding hydrazides N- benzoíladas which undergo condensation reaction with p-clorofenila isocyanate to form the 4-acyl-semicarbazides isoxazolínicas. Finally, cyclization of the 4-acyl semicarbazide was carried out in basic medium to form the 1,2,4-triazole azabicyclic isoxazolínico. All new products were identified and characterized using infrared spectrometry and spectroscopy of 1H NMR and 13C. Biological tests, antinociceptive and antimicrobial activity, new 4-acyl-semicarbazides and 1,2,4-triazole are as of this perspective work.
2

Mineral Surface-Mediated Transformation of Insensitive Munition Compounds

Khatiwada, Raju, Khatiwada, Raju January 2016 (has links)
Abiotic transformation of compounds in the natural environment by metal oxides plays a significant a role in contaminant fate and behavior in soil. The ability of birnessite, ferrihydrite and green rust to abiotically transform insensitive munitions compounds (IMCs) parent (2,4 dinitroanisole [DNAN] and 3-nitro-1,2,4-triazol-5-one [NTO]), and daughter products (2-methoxy-5-nitro aniline [MENA], 2,4-diaminoanisole [DAAN]of DNAN; and 5-amino-1, 2, 4-triazol-3-one [ATO] of NTO) was studied in batch reactors under strictly controlled pH and ionic strength. The objectives of the study were to (i) assess the abiotic transformation potential of soluble DNAN, MENA, DAAN, NTO and ATO by birnessite, ferrihydrite and green rust, and (ii) identify inorganic reaction products. The study was carried out at metal oxide solid to IMC solution ratios (SSR) of 0.15, 1.5 and 15 g kg⁻¹ for birnessite and ferrihydrite and 10 g kg⁻¹ for green rust. Aqueous samples were collected at time intervals between 0 to 3 days after the reaction initiation and analyzed using HPLC with UV detection. Results indicated that DNAN was resistant to oxidation by birnessite and ferrihydrite at given solid to solution ratios. MENA was susceptible to rapid oxidation by birnessite (first order rate constant, 𝑘=1.36 h⁻¹ at 15 g kg⁻¹ SSR). The nitro groups from MENA largely mineralized to nitrite (NO₂⁻). In contrast, ferrihydrite did not oxidize MENA. DAAN was susceptible to oxidation by both birnessite and ferrihydrite, but about a six times higher oxidation rate was observed with birnessite (𝑘=1.18 h⁻¹) as compared to ferrihydrite (𝑘=0.22 h⁻¹) at an SSR of 1.5 g kg⁻¹. There was a complete loss of DAAN from solution after 5 min with birnessite at an SSR 15 g kg⁻¹ (𝑘≥90.5 h⁻¹). CO₂ evolution experiments indicate mineralization of 15 and 12 % of carbon associated with MENA and DAAN, respectively; under aerobic conditions with birnessite at an SSR of 15 g kg⁻¹. NTO was resistant to oxidation by birnessite and ferrihydrite at any SSR; however, there was slight initial loss from solution upon reaction with ferrihydrite at 0.15 and 1.5 g kg⁻¹ SSR and complete loss at 15 g kg⁻¹ SSR due to adsorption. ATO was susceptible to oxidation by birnessite and sorption by ferrihydrite. The first order rate constants (𝑘) for ATO with birnessite at 0.15 and 1.5 g kg⁻¹ SSR are 0.04 and 3.03 h⁻¹ respectively. There was complete loss of ATO from solution with birnessite at 15 g kg⁻¹ SSR (𝑘 ≥ 90.2 h⁻¹) within 5 min of reaction. Transformation products analysis revealed urea, CO₂ and N₂ as major reaction products with 44 % urea recovery and recovery of 51.5 % of ATO carbon as CO₂ and 47.8 % of ATO nitrogen as N₂ at 15 g kg⁻¹ SSR. The oxidation of ATO in the presence of birnessite was found to be independent of dissolved O₂. The results indicate that ATO, the major reductive (bio)transformation product of NTO, is readily oxidized by birnessite in soil. NTO was found strongly sorbed to ferrihydrite as compared to that of ATO. The results of the green rust experiment indicate rapid abiotic reduction of parent compounds NTO and DNAN to their reduced aminated daughter products. NTO was generally reductively transformed to 5-amino-1, 2, 4-triazol-3-one (ATO) within 10 min and completely reacted in 20 min. DNAN was rapidly transformed to its reduced daughter products MENA and 4-methoxy-5-nitroaniline (iMENA). The reduction occurred with a distinctive, staggered regioselectivity. Over the first 10 min, the para-nitro group of DNAN was selectively reduced, generating iMENA. Thereafter the ortho-nitro group was preferentially reduced, generating MENA. Both iMENA and MENA were subsequently transformed to the final reduction product DAAN within 1 day. X-ray absorption near edge spectroscopy data suggested oxidative transformation of green rust to lepidocrocite-like mineral forms, accounting for 94 % of the mineral products in the case of NTO reaction as compared to 62 % in the case of DNAN. The results taken as whole suggest that complete abiotic transformation of IMCs could be achieved by coupled stepwise green rust and birnessite treatments.
3

Síntese e aplicação de sílica modificada na adsorção de Cu(II), Cd(II) e As(V) em meio aquoso : pré-concentração em amostras de águas naturais /

Wondracek, Marcos Henrique Pereira. January 2017 (has links)
Orientador: Gustavo Rocha de Castro / Resumo: Este trabalho relata o desenvolvido de métodos analíticos que visa à determinação de algumas espécies tóxicas e potencialmente tóxicas de metais e metalóides em níveis ultra-traço em amostra de água naturais, utilizando uma técnica analítica menos sensível, como a espectrometria de absorção atômica em chama (FAAS). Essa técnica foi escolhida por ser relativamente simples e possuir baixo custo operacional. A técnica de extração em fase sólida (EFS), utilizando um novo material sorvente, foi utilizada para separar e pré-concentrar os analitos. Este estudo demonstra o procedimento de uma nova rota sintética via co-condensação visando à produção de uma sílica mesoporosa organofuncionalizada com o ligante 4-amino-3-hidrazino-5-mercapto-1,2,4-triazole e, sua utilização como sorvente para pré-concentração/análise de especiação de íons metálicos em amostras de água. O material produzido foi caracterizado por espectroscopia na região do infravermelho (FTIR), BET, ressonância magnética nuclear (RMN) de 29Si e 13C, dentre outras. As características adsortivas desse material foram estabelecidas em estudos de batelada, onde se estudou o efeito do pH, cinética de adsorção e capacidade máxima de adsorção. A otimização multivariada foi utilizada para obtenção das melhores condições químicas e de fluxo no sistema de pré-concentração, permitindo avaliar as interações principais e secundárias entre os fatores. Por meio da análise dos espectros obtidos por FTIR foi possível observar bandas de es... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This paper reports on the development of analytical methods for the determination of some toxic and potentially toxic species in ultra - trace levels in natural water samples using a less sensitive analytical technique such as flame atomic absorpti on spectrometry (FAAS). This technique was chosen because it is relatively simple and has a low operating cost. The solid phase extraction technique (SPE) using a new sorbent material was used to separate and preconcentrate the analyte. This study demonstr ates the procedure of a new synthetic route using the technique of the co - condensation for the production of a mesoporous organo - functionalised silica with the 4 - amino - 3 - hydrazino - 5 - mercapto - 1,2,4 - triazole ligant and its use as a sorbent for preconcentrati on/ analysis of metal ion s speciation in water samples. The material produced was characterized by infra - red spectroscopy (FTIR), BET, 29 Si and 13 C nuclear magnetic resonance (NMR), among others. The adsorptive characteristics of this material were establis hed in batch studies, where the effect of pH, adsorption kinetics and maximum adsorption capacity were studied. Multivariate optimization was used to obtain the best chemical and flow conditions in the preconcentration system, allowing the evaluation of th e main and secondary interactions among the factors. By means of the analysis of the spectra obtained by FTIR, it was possible to observe C - H, C - Cl and (NH 2 ) stretch bands from the organic frac... (Complete abstract click electronic access below) / Doutor
4

Síntese e aplicação de sílica modificada na adsorção de Cu(II), Cd(II) e As(V) em meio aquoso: pré-concentração em amostras de águas naturais / Synthesis and application of modified silica in Cu (II), Cd (II) and As (V) adsorption in aqueous media: preconcentration in natural water samples.

Wondracek, Marcos Henrique Pereira [UNESP] 05 October 2017 (has links)
Submitted by MARCOS HENRIQUE PEREIRA WONDRACEK null (marcoswondracek@ufgd.edu.br) on 2017-10-29T05:42:20Z No. of bitstreams: 1 TESE - versão final.pdf: 3488966 bytes, checksum: 44030b3422f6b77b9ba441eb0905cb23 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-11-09T13:58:32Z (GMT) No. of bitstreams: 1 wondracek_mhp_dr_araiq.pdf: 3488966 bytes, checksum: 44030b3422f6b77b9ba441eb0905cb23 (MD5) / Made available in DSpace on 2017-11-09T13:58:32Z (GMT). No. of bitstreams: 1 wondracek_mhp_dr_araiq.pdf: 3488966 bytes, checksum: 44030b3422f6b77b9ba441eb0905cb23 (MD5) Previous issue date: 2017-10-05 / Item merged in doublecheck by Monique Sasaki (sayumi_sasaki@hotmail.com) on 2017-12-07T17:59:08Z Item was identical to item(s): 153113, 153193 at handle(s): http://hdl.handle.net/11449/152063, http://hdl.handle.net/11449/152164 / Este trabalho relata o desenvolvido de métodos analíticos que visa à determinação de algumas espécies tóxicas e potencialmente tóxicas de metais e metalóides em níveis ultra-traço em amostra de água naturais, utilizando uma técnica analítica menos sensível, como a espectrometria de absorção atômica em chama (FAAS). Essa técnica foi escolhida por ser relativamente simples e possuir baixo custo operacional. A técnica de extração em fase sólida (EFS), utilizando um novo material sorvente, foi utilizada para separar e pré-concentrar os analitos. Este estudo demonstra o procedimento de uma nova rota sintética via co-condensação visando à produção de uma sílica mesoporosa organofuncionalizada com o ligante 4-amino-3-hidrazino-5-mercapto-1,2,4-triazole e, sua utilização como sorvente para pré-concentração/análise de especiação de íons metálicos em amostras de água. O material produzido foi caracterizado por espectroscopia na região do infravermelho (FTIR), BET, ressonância magnética nuclear (RMN) de 29Si e 13C, dentre outras. As características adsortivas desse material foram estabelecidas em estudos de batelada, onde se estudou o efeito do pH, cinética de adsorção e capacidade máxima de adsorção. A otimização multivariada foi utilizada para obtenção das melhores condições químicas e de fluxo no sistema de pré-concentração, permitindo avaliar as interações principais e secundárias entre os fatores. Por meio da análise dos espectros obtidos por FTIR foi possível observar bandas de estiramento C–H, C–Cl e (NH2) oriundos da fração orgânica do material. A área superficial foi de 369,84 m2 g-1com diâmetro médio de poros em 7,1 nm, relacionados a materiais mesoporosos. Os resultados obtidos por RMN de 29Si comprovam a formação do material híbrido, sintetizado por co-condensação, e o RMN de 13C confirma o ancoramento do ligante na matriz. O pH que favorece a adsorção dos íons foi 5,0 para Cu(II) e 3,0 para Cd(II) e As(V). O modelo cinético de pseudo segunda ordem apresentou melhor ajuste aos dados experimentais, indicando adsorção química. Os dados de sorção desses íons metálicos mostraram bom ajuste ao modelo de Langmuir, com capacidade máxima de adsorção próxima aos valores obtidos experimentalmente, 0,057, 0,018 e 0,060 mmol g-1 para Cu(II), Cd(II) e As(V), respectivamente, indicando que a sorção ocorre em monocamada. Os parâmetros analíticos encontrados para o Cu(II) foram: fator de pré-concentração de 18,1; intervalo linear de 10,0 – 200,0 µg L-1 (R = 0,999) e LD de 1,45 µg L-1. Para o Cd(II): fator de pré-concentração de 15,8; intervalo linear de 2,0 – 100,0 µg L-1 (R = 0,999) e LD de 0,38 µg L-1. Para o As(V): fator de pré-concentração de 5,0; intervalo linear de 0,25 – 2,5 µg L-1 (R = 0,999) e LD de 0,039 µg L-1. A exatidão foi checada pelo método de adição e recuperação e/ou método comparativo com GFAAS ou ICP OES. As recuperações variaram de 97 – 106% (Cu), 100 – 105% (Cd), 88 – 103% (As(V)) e 96 – 106% (As(total)). Os resultados para Cu(II) determinados com os métodos propostos foram concordantes com os obtidos com o método comparativo. Conclui-se que o material produzido apresenta bom potencial para ser aplicado na extração/pré-concentração de cobre, cádmio e análise de especiação inorgânica de arsênio. Provou-se também que baixos limites de detecção e quantificação podem ser obtidos mesmo utilizando uma técnica menos sensível como a FAAS. / This paper reports on the development of analytical methods for the determination of some toxic and potentially toxic species in ultra - trace levels in natural water samples using a less sensitive analytical technique such as flame atomic absorpti on spectrometry (FAAS). This technique was chosen because it is relatively simple and has a low operating cost. The solid phase extraction technique (SPE) using a new sorbent material was used to separate and preconcentrate the analyte. This study demonstr ates the procedure of a new synthetic route using the technique of the co - condensation for the production of a mesoporous organo - functionalised silica with the 4 - amino - 3 - hydrazino - 5 - mercapto - 1,2,4 - triazole ligant and its use as a sorbent for preconcentrati on/ analysis of metal ion s speciation in water samples. The material produced was characterized by infra - red spectroscopy (FTIR), BET, 29 Si and 13 C nuclear magnetic resonance (NMR), among others. The adsorptive characteristics of this material were establis hed in batch studies, where the effect of pH, adsorption kinetics and maximum adsorption capacity were studied. Multivariate optimization was used to obtain the best chemical and flow conditions in the preconcentration system, allowing the evaluation of th e main and secondary interactions among the factors. By means of the analysis of the spectra obtained by FTIR, it was possible to observe C - H, C - Cl and (NH 2 ) stretch bands from the organic fraction of the material. The surface area was 369.84 m 2 g - 1 with a verage pore diameter at 7.1 nm related to mesoporous materials. The results obtained by 29 Si NMR prove the formation of the hybrid material, synthesized by co - condensation, and the 13 C NMR confirms the anchoring of the ligan t in the matrix. The pH 5.0 it w as favors the adsorption of the ions Cu (II), the pH 3.0 it was favors the adsorption of the Cd (II) and As (V). The kinetic model of pseudo second order showed better adjustment to the experimental data, indicating chemical adsorption. The adsorption data of Cu (II), Cd (II), and As (V) were similar to those of the Langmuir model, with a maximum adsorption capacity of 0.057, 0.018 and 0.060 mmol g - 1 for Cu (II), Cd(III) and As(V) , respectively, indicating that the sorption occurs in monolayer. The analyt ical parameters for Cu (II) were: preconcentration factor of 18.1; linear range of 10.0 - 200.0 μg L - 1 (R = 0.999) and LD of 1.45 μg L - 1 . For Cd (II): preconcentration factor of 15.8; linear range of 2.0 - 100.0 μg L - 1 (R = 0.999) and LD of 0.38 μg L - 1 . Fo r As (V): preconcentration factor of 5.0; linear range of 0.25 - 2.5 μg L - 1 (R = 0.999) and LD of 0.039 μg L - 1 . Accuracy was checked by addi tion and recovery method of the standard and/ or comparative method with GFAAS or ICP OES. The recovery ranged from 97 - 106% Cu(II), 100 - 105% Cd (II), 88 - 103% As (V) and 96 - 106% As (total)). The results for Cu (II) determined with the proposed methods were concordant with those obtained with the comparative. It is concluded that the material produced can be successfully applied in the extraction / preconcentration of copper, cadmium and analysis of inorganic speciation of arsenic and low limits of detection and quantification can be obtained even using a less sensitive technique such as FAAS.

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