Mestrado em Química (IQ)
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Item 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/4961539278604455In 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.Item 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/2129799749473005The 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.Item 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/8443681172569310The 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.Item 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/7884708272070266This 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.Item 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/7884708272070266In 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.