Programa de Pós-graduação em Química

URI Permanente desta comunidade

http://200.137.215.59/tede/handle/tde/268

Navegar

Agora exibindo 1 - 8 de 8

Síntese e avaliação de óxido de ferro suportado em carvão ativado polimérico como catalisador na desidrogenação do etilbenzeno
(Universidade Federal de Goiás) Barbosa, Danns Pereira; Rabelo, Denilson; http://lattes.cnpq.br/4961539278604455
In this work, activated carbon were synthesized through carbonization of a polymer, containing iron oxides with and without copper. The precursor of activated carbon was a styrene?divinylbenzene copolymer (Sty?DVB) synthesized through suspension polymerization, in the presence of inert diluentes to obtain a macroporous structure. The resin was sulfonated with sulfuric acid, in the presence of dichloroethane. For the synthesis of the supported catalysts, on first it was carried out oxide precipitation in the sulfonated resin and later a thermal treatment to obtain the carbonizated structures. The oxides synthesis were accomplished in three stages: the) incorporation of Fe2+ ions with or without Cu2+ in the resin by ion exchange; b) washing to remove the íons that were not adsorbed; c) coprecipitation in alkaline and oxidant solution. The thermal treatment consisted in calcination of polymer/oxide composite at 250 ºC, carbonization at 900 ºC and activation at 900 ºC with steam. The effect of copper concentration and presence of the support were investigated in the reaction of ethylbenzene dehydrogenation with and without steam. For comparison, bulk catalysts were prepared with the same conditions of coprecipitation of Fe2+ or Cu2+ ions for supported catalysts without the use of sulfonated resin. The materials were characterized by chemical analysis, X rays diffraction, termogravimetric analysis and porosity measurements by nitrogen physical adsorption. It was verified that the polymeric matrix affected the oxide type produced in comparison with coprecipitations in solution. The supported catalysts had better catalytic activities than the bulk and comercial ones because their higher porosities and specfic surface areas. Besides, during the reaction, they presented small tendence sinterization and coke formation. The last property is an intrinsic characteristic of the support based on polymeric activated carbon.
Composição e variabilidade química dos óleos essenciais das folhas e frutos de Eugenia dysenterica
(Universidade Federal de Goiás, 2008) Duarte, Alessandra Rodrigues; Ferri, Pedro Henrique; http://lattes.cnpq.br/2129799749473005
The chemical variations in the essential oil compositions of the wild and cultivated Eugenia dysenterica DC. (Myrtaceae) populations indicated the presence of two clusters of oils according to sampling origin. The cluster I included cultivate (subcluster IA) and mainly wild samples (subcluster IB) originating from Senador Canedo (SC), with high percentages of a-pinene (9.0 ± 2.3%), b-pinene (9.3 ± 2.6%), (Z)-b-ocimene (5.9 ± 4.2%) and g-cadinene (27 ± 5%), limonene (12 ± 9%), and caryophyllene oxide (7.4 ± 4.7%), respectively. In cluster II, with wild and cultivated samples originating from Campo Alegre de Goiás, the major constituents were b-caryophyllene (24 ± 8%), d-cadinene (13 ± 4%), and a-copaene (9.6 ± 3.2%). The canonical correlation analysis revealed that limonene, ?-cadinene, caryophyllene oxide, Zn, Cu, Fe, Mn, and mean monthly values of temperature and precipitation were quite strongly related to SC wild samples (subcluster IB), whereas (Z)-b-ocimene, a-copaene, b- caryophyllene, a-humulene, d-cadinene, and P were related to wild samples from CA and cultivated samples, regardless of population origin (subcluster IA and cluster II). Sesquiterpene hydrocarbons predominated in all population sampled and the observed essential oil chemovariation might be genetically determined (chemotypes), in addition to a clear environmental influence on the samples originating from SC site (ecotypes). Chemical variations in essential oil compositions of cultivated E. dysenterica populations in dry and wet seasons have indicated the presence of two oil clusters related to sampling origin and seasons. Cluster I included dry (subcluster IA) and mainly wet samples (subcluster IB) originating from Senador Canedo (SC), with high percentages of b-pinene?(9.3 ± 2.6%), a-pinene (9.0 ± x 2.3%), (Z)-b-ocimene (5.9 ± 4.2%) and g-cadinene (17 ± 11%), limonene (14 ± 9%), and b-pinene?(8.6 ± 5.4%), respectively. In cluster II, which included dry and wet cultivated samples originating from Campo Alegre de Goiás, the major constituents were b-caryophyllene (32 ± 15%), d-cadinene (13 ± 6%), and a- copaene (8.1 ± 4.0%). Here also, sesquiterpene hydrocarbons predominated in all the sampled populations and the observed essential oil chemovariation might be genetically determined, in addition to a clear seasonal influence only on the samples originating from the SC site. In addition, the oils from wild E. fruits harvested during three stages of ripening showed the monoterpene hydrocarbons as most abundant group of volatiles, accounting for about 68% of the total identified compounds. Limonene (25.8% and 24.6%), (E)-b-ocimene (20.3% and 21.7%) and b-pinene (12.0% and 14.2%) were the compounds in the unripe and semi-ripe stages, respectively, while g-muurolene (25.8%), b-caryophyllene (18.4%) and a- humulene (15.4%) became the major compounds in ripe fruits. The concentration of monoterpenes was high in the unripe and semi-ripe stages and decreased afterwards, while sesquiterpenes were intensively synthesized only in the last part of the ripening process.
Saberes profissionais para o exercício da docência em química voltado à educação inclusiva
(Universidade Federal de Goiás, 2014-03-18) Field's, Karla Amâncio Pinto; Benite, Anna Maria Canavarro; http://lattes.cnpq.br/8433607360245647; Benite, Anna Maria Canavarro; Silva, Rejane Maria Ghisolfi da; Silveira, Helder Eterno da; Guimarães, Simone Sendin M.; Echeverría, Agustina Rosa
This study investigated the construction and mobilization of teaching knowledge to train chemistry teachers for school inclusion. The research was especially guided by aspects intrinsic to qualitative approach. We chose an action-research, given the purpose of providing to those involved the conditions to think, reflect and discuss the nature and complexity of real problems we are experiencing. This research was developed in two spiral cycles of action-research. The first cycle included the planning and development of the free core subject entitled Foundations of Inclusive Education (FIE) in 2010, and the second cycle was the development of supervised training at the Brazilian Center for Support and Rehabilitation of the Visually Impaired (CEBRAV) in 2011. The participants were students of the subject FEI, trainees of the Education Degree in Chemistry who have developed their internships at CEBRAV and visually impaired students of CEBRAV. The instruments for data collection were, for the 1st cycle, the collective diaries and in the 2nd cycle, we use the collective diaries and transcripts of audio and video recordings of pedagogical interventions (PI) performed in CEBRAV. The collected data were analyzed using content analysis technique (CA) and through the transcripts of PI. The narratives produced in collective diaries indicated that students of the subject FEI have appropriated the discussions promoted in groups, through reflection by confrontation with that provided by law for the reality of public schools in the state of Goiás. The initial training should encourage and enable future teachers to take part of researches in the area of inclusive education, which seek to understand the circumstances and dilemmas of the school context, so that they can appropriate experiential and professional knowledge, which are related with community, dialogue and partnership in building a school for everyone.
Análise Ecotoxicológica e Química da Estação de Tratamento de Efluentes de uma Indústria de Laticínios em Goiás
(Universidade Federal de Goiás, 2011-08-26) Machado, Victor Vinicius Batista; Tavares, Maria Gizelda de Oliveira; http://lattes.cnpq.br/0066533047918329; Leles, Maria Inês Goncalves; http://lattes.cnpq.br/1614912440064013; Coltro, Wendell Karlos Tomazelli Coltro; http://lattes.cnpq.br/8302650734477213; Brait, Carlos Henrique Hoff; http://lattes.cnpq.br/8443681172569310
The dairy industries represent one of the most important sectors for the economy of Goiás. The intense industrialization, together with the lack of specialized labor, means that these industries generally produce without any concern for the waste generated. Besides solid waste, these industries generate effluents with high levels of pollution that can affect the water and soil quality, in water bodies into which they flow. Faced with this scenario, the need arose to carry out a study of the risks inherent to this type of effluent, both from a physical-chemical and ecotoxicological point of view. For this purpose, acute toxicity studies were carried out with the Zebrafish (Danio rerio), to evaluate the toxicity of the effluents in pre-defined points of the Wastewater Treatment Plant (WTP) analyzed (points A, D and F). To evaluate the efficiency of the WTP, some physical-chemical parameters were measured (pH, conductivity, cloudiness, BOD, COD, TS, OG among others), and a chemical analysis was carried out of the metals Zn, Cd, Cu and Pb. To determine the solid residues in the effluent, thermogravimetric analyses were performed. Through mathematical models, the efficiency of the WTP was evaluated in terms of the parameters measured, which throughout the treatment process, proved inefficient, presenting mainly negative values. The tests of acute toxicity carried out with the test organisms in contact with the effluent from the dairy effluent, collected in various points of the plant, enabled the LC50 to be calculated, which indicated a moderate to high toxicity of the effluents analyzed.
Estudo da reatividade de N-(2-hidroxietil)-N'-(4-metilfenil) guanidina com cobre (II): uma abordagem experimental e computacional
(Universidade Federal de Goiás, 2011-02-25) Magalhães, River Souza; Souza, Aparecido Ribeiro de; http://lattes.cnpq.br/7884708272070266
This work presents the synthesis of N-[-(4-methylphenyl)]-thiourea, the ligand N-[N'-(2-hydroxyethyll)-(4-methylphenyl)]-guanidine and the copper II complex. The compounds were characterized by infrared spectroscopy,1H NMR and X-ray diffraction. The results of X-ray shows the mode of ligand coordination to the metal ion, in addition to square planar structure, a connection is observed for the trans chromophore CuN2O2. Conformational studies of the molecule the ligand N-[N'-(2-hydroxyethyl)-(4-methylphenyl)]-guanidine and were performed to compare experimental data with calculated data. the computation of ligand molecule N-[N'-(2-hydroxyethyl)-(4-methylphenyl)]-guanidine shows the small energy difference between the threes tautomers, it is not possible to state firmly the most stable. The 1H NMR data show that the solution is more abundant in the tautomer II and III. Calculations of energy transition states for the reaction path. In addition to the calculations of imaginary for the characterization of transition states.
Citrato de rodio (II): síntese, caracterização, adsorção em nanopartículas de maguemita e preparação de fluidos magnéticos
(Universidade Federal de Goiás, 2010-03-10) Nunes, Eloiza da Silva; Souza, Aparecido Ribeiro de; http://lattes.cnpq.br/7884708272070266
In this work are described the synthesis and characterization of dinuclear rhodium(II) citrate, adsorption study in maghemite nanoparticles, and preparation of nanoparticles-modified based magnetic fluids. Rhodium(II) citrate has significant antitumor activity being promissory to cancer chemotherapy. Due to the existence of free functional groups in its molecular structure this complex has capacity to functionalize iron oxide nanoparticles to produce drug-particles formulations. The modified nanoparticles show features of biocompatibility suitable to use the system in medical applications. Rhodium(II) citrate was synthesized by an exchange reaction of trifluoroacetate ligands from the precursor rhodium(II) trifluoroacetate by citrate ligands. The products were characterized by C and H elemental and thermogravimetric analysis, mass spectrometry, and infrared, UV/visible and 13C nuclear magnetic resonance spectroscopy. The results are consistent with the formation of dinuclear structure characteristic for rhodium(II) carboxylates. Changing the synthesis conditions were obtained products with stoichiometries [Rh2(H2cit)2(H2O)4] and [Rh2(H2cit)4(H2O)2]. The results and compounds solubility observations suggest that the first one occur as a coordination polymer. The second one showed composition e solubility behavior consistent with the formation of monomeric units. Maghemite nanoparticles with size mean between 5 and 7 nm were obtained through alkaline coprecipitation of Fe2+ and Fe3+ ions with further oxidation with oxygen gas. The solids were characterized by X-ray difratometry and the Scherrer relation was use to calculate the crystallite size mean. Adsorption experimental data were adjusted to Langmuir model and linear coefficients obtained, R2, were greater than 0,99. Functionalized nanoparticles were dispersed into water producing a stable colloid. Dispersion s characterization was performed by absorbance, zeta potential, and hydrodynamic diameter measurements. Surface properties and colloidal behavior of functionalized nanoparticles are much affected by adsorbed species. The colloidal stability of the magnetic fluids is dependent on the adsorbed amounts of rhodium(II) citrate and pH. When the adsorbed amount of rhodium(II) citrate is next to saturation, the magnetic fluids are stable in pH over 3 and show hydrodynamic diameter around 60 nm. Fluids colloidal stability is preserved against physiologic saline solution, PBS buffer, and fetal bovine serum over a period of 30 days.
Contribuição ao estudo de espécies da família Rubiaceae: gênero amaioua
(Universidade Federal de Goiás, 2014-03-07) Oliveira, Pollyanna Laurindo; Oliveira, Cecília Maria Alves; http://lattes.cnpq.br/3152041311943092; Oliveira, Cecília Maria Alves de; Garcez, Walmir Silva; Foglio, Mary Ann; Lião, Luciano Morais; Sabino, José Ricardo
The Amaioua genus (Rubiaceae) is included in the subfamily Ixoroideae. The genus comprises 10 species, ranging from Panama to Peru, Venezuela and Brazil, and four of these species are found in Cerrado (DELPRET et al., 2004b). There are no records in the literature on the popular use of the Amaioua genus. Amaioua guianensis Aulb is a shrub up to 3 m or a 10-20 m tree, popularly known as marmelada-brava ou marmelinho-vermelho. Phytochemical studies of leaves and twigs of this species led to the isolation of several classes of secondary metabolites, such as coumarins, a cyclopeptide alkaloid, pentacyclic triterpenes, proanthocyanidins and chlorogenic acids (OLIVEIRA,2009). Amaioua intermedia Mart, popularly known as carvoeiro, pau-carvão, cinzeiro, canela-de-veado, guapeva-forte or marmelada-brava, presents itself as shrubs up to 3 m or 15 m trees. Until the moment there are no records in the literature about a phytochemical study of A. intermedia,. As part of our phytochemical research for new compounds from higher plants, we studied the ethanolic extracts of A. guianensis and A. intermedia, and evaluated the antioxidant activity of such extracts and fractions obtained from them. Herein we describe the isolation and structural elucidation of a new kaurane diterpene (compound 8), a new cyclopeptide alkaloid (compound 19), two new secologanin iridoid (compounds 24 and 25, and seventeen known compounds: a cyclopeptide alkaloid (compound 7), five iridoids (compounds 1, 13, 14, 15 and 16), a ent-kaurane diterpene (compound 22), two dimeric proanthocyanidins (compounds 11 and 12), three pentacyclic triterpenes (compounds 9, 20 and 21), a sugar (compound 10) and four steroids (compounds 3, 4, 5 and 6). The antioxidant activity analysis of the raw extracts obtained from fruits, roots, leaves and twigs of A. guianensis, as well as the raw extracts from the leaves and twigs of A. Intermedia, showed that they reacted to the DPPH radical, leading to a loss of 50% in its absorbance, on the following concentrations of 71.87, 7.55, 5.30, 7.48, 46.83 and 57.42 mg/mL.
Influência ambiental, especial e genética na composição química dos óleos essenciais de Eugenia dysenterica DC (Myrtaceae)
(Universidade Federal de Goiás, 2014-03-28) Vilela, Eliane da Costa; Ferri, Pedro Henrique; http://lattes.cnpq.br/2129799749473005; Ferri, Pedro Henrique; Alves, Sueli Martins de Freitas; Costa, Maísa Borges; Kato, Lucília; Seraphin, José Carlos
The chemical composition of essential oils was used to study the spatial structure of eight E. dysenterica populations in central Brazilian Cerrado. Variation partitioning using spatial and environmental data sets as predictors was highly significant and explained 8.2% and 11.1% of oil chemovariations, respectively. The data suggested wich essential oil polymorphism was genetically rather than environmentally determined. Furthermore, the intercept of the multivariate Mantel autocorrelogram between the distance matrices of oil constituents and sampling sites suggested that the populations differ chemically whenever geographical distance exceeds 120 km. The spatial chemometric methods using variograms and probability maps detected and characterized the spatial chemical structure among populations, as well as the environmental factors responsible for them. All these strategies indicated that the populations differ chemically whenever the geographical distance exceeds 120 km, an indicator of the minimal distance between samples required for conserving the genetic diversity of populations. Although being scarcely used with secondary metabolites, these methodologies may be used in a wide range of applications in species management and may lead to an effective integration of genetic, chemical and ecological perspectives.

Navegar

Navegando Programa de Pós-graduação em Química por Por tipo de Acesso "Acesso aberto"

Resultados por página

Opções de Ordenação