Programa de Pós-graduação em Química

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Novas abordagens em petroleômica: extração e caracterização de ácidos naftênicos de águas produzidas por espectrometria de massas de ultra-alta resolução
(Universidade Federal de Goiás, 2020-02-12) Aguiar, Deborah Victória Alves de; Vaz, Boniek Gontijo; lattes.cnpq.br/781453471055063; Vaz, Boniek Gontijo; Coltro, Wendell Karlos Tomazelli; Carvalho, Rogério Mesquita de
Oil production is accompanied by water production, called produced water (PW), which is abundant in reservoirs. By being in contact with oil and in high-pressure environments, some components of oil, by equilibrium, can be transferred to water, such as naphthenic acids (NAs). NAs are associated with corrosion problems, scale formation and deposits, and high toxicity to aquatic biota. Here, we propose the use of solvent-terminated dispersive liquid-liquid microextraction (ST-DLLME) coupled with high-resolution mass spectrometry (UHR MS) in order to extract and detect PW dispersed and dissolved NAs, as well as to analyze the distribution of NAs in the oil/water balance. At first, the optimization of solvents to be used and the influence of the pH of sample AP 1 on the extraction of dispersed NAs were performed. Seven solvent systems (dispersing solvent + extracting solvent + demulsifying solvent) were used at pHs 2, 7, and 10. For analysis of dissolved NAs, sample PW 1 was subjected to a n-hexane clean-up step for removal of dispersed oil droplets. Extractions of the dispersed NAs showed that at pH 2 the solvent system that obtained the highest percentage of extracted Ox class was 7 (DCM / CH / Ace). At pH 7 and 10 in the solvent system 2 (CH / Tol / Ace) compounds above C30 were detected and a double bond equivalent (DBE) variation was found between 1 and 11. After clean-up with n-hexane a decrease of the detected carbon number range as well as the DBE range was found. The distribution of NAs in oil/water allowed for the analysis of which NAs are most likely to be transferred to water produced in both dispersed and dissolved form. In addition, ST-DLLME and miniaturized liquid-liquid extraction (LLE) were employed as extraction methodologies for samples AP 2, AP 3 and AP 4, in which it was observed that ST-DLLME reached carbon number values and DBE value higher than miniaturized LLE. In summary, ST-DLLME coupled with UHR MS can be a valuable analytical tool for the extraction of naphthenic acids in produced waters, since the use of this extraction technique minimizes the consumption of samples and solvents.
Células solares de perovskitas: uma análise da qualidade das informações em bases de patentes e em artigos científicos
(Universidade Federal de Goiás, 2019-04-24) Aguiar, Lucas Fernandes; Martins, Tatiana Duque; http://lattes.cnpq.br/9082478597898534; Martins, Tatiana Duque; Santos, Nivaldo dos; Soares, Marlon Herbert Flora Barbosa
Perovskite solar cells have been the biggest driver in solar cell development in the last few years because of its low cost, it is easy to manufacture and has high power conversion efficiencies. The progress of this technology has been observed by the records achieved in efficiency since 2011 and rapidly caught the attention of the scientific community. The perovskites used are of the halogen hybrids type, where it is present a organic cation CH3NH3, a heavy metal, commonly Pb or Sn, and halogen ions or a mixture, commonly I, Br, and Cl. This study focused on understanding, by searching in patent and scientific article databases, the data that could show how the development of this technology happened, giving a bird’s eye view of the current development in the solar cell sector, as well as showing, from the results obtained, the possible routes for the development of new technologies in Brazil. Through this search it was possible to point out the main differences between the models used for developing new technologies currently in use in Asia, Europe and Brazil, as well as determine the dependency relation between the development and the the use of the international patent system and how it is fundamental for the launching of new products based on perovskite.
Síntese, caracterização físico-química e elucidação estrutural de bischalconas simétricas
(Universidade Federal de Goiás, 2019-06-07) Almeida, Lívia Oliveira Alves Ferreira de; Martins, Felipe Terra; http://lattes.cnpq.br/0466799995060671; Noda Pérez, Caridad; http://lattes.cnpq.br/7849604313803596; Noda Pérez, Caridad; Lariucci, Carlito; Costa, Maísa Borges
In the present work the synthesis, characterization of seven symmetric bischalcones, of which two are unpublished, and the structural elucidation by means of the crystallography of one of them, besides the cytotoxic analysis of all the compounds against 3 different lines of cancer. After synthesizing the compounds were characterized by 1 H Nuclear Magnetic Resonance (NMR), melting point, infrared (IR), Mass Spectrometry (MS) and elemental analysis of C and H (CHN). The compounds were obtained by the reaction of aldol condensation between the acetone and the benzaldehydes for substituted, in a yield of between 81.19 and 26.92%. The results of 1 H NMR, MS and CHN analyzes confirmed that the expected compounds were obtained in high purity. The crystallographic study was chosen as a technique to elucidate crystalline structure because it has been shown to be of fundamental importance to know the molecular arrangement and thus serving as an important tool for pharmacology and other related areas. The data of the unpublished molecule were obtained by X-ray diffraction of monocrystal, thus allowing to evaluate the geometric parameters, the distances and the interatomic angles, intermolecular interactions and the supramolecular arrangement. The selected crystal crystallized in the monoclinic system with four symmetry operations and a 50% disorder in two of its atoms, its interatomic distances and its binding angles were measured and compared with structures previously deposited in the Cambridge Crystallographic Data Center (CCDC). With the aid of 13 C solid-state nuclear magnetic resonance (NMR-s) and theoretical energy analysis, the presence of the mixed anti-syn confomer was detected. Considering the great advance in the studies of bischalcone and its potential tumor inhibitor, these compounds were sent to the Nucleus of Research and Development of Medicines (NRDM) of the Federal University of Ceará (UFC), with the purpose of evaluating its antitumor activity against the human cancer cells (SNB-19) (glioblastoma), PC-3 (prostate) and HCT-116 (colon), obtaining values of inhibition of growth in the 11% to 100%, and the ability to inhibit (IC 50 ) 50% of cell proliferation from 0.48 to 13.17 μg.ml -1 , the best compound being the 5.
Síntese e caracterização de nanopartículas de maguemita recobertas com sílica funcionalizada com grupos amina
(Universidade Federal de Goiás, 2008-11-25) ALMEIDA, Michelly Patrícia Santana de; SARTORATTO, Patrícia Pommé Confessori; http://lattes.cnpq.br/9777959525393785
Magnetic nanoparticles coated with several kinds of materials have been the focus of intense research due to their potential applications in biomedicine. This type of material contains a magnetic core that is involved by a shell of different composition. The coating of magnetic nanoparticles with amino-functionalized silica is particularly important because of its reactivity which allows the coupling with biological molecules such as fragments of DNA, antibodies, proteins, among others. In this work, maghemite nanoparticles were coated with silica and with amino-functionalized silica, the incorporation of them being achieved by using tetraethoxysilane (TEOS) and aminopropyltrimethoxysilane (APTS) as the precursors of the sol-gel system. Firstly, the magnetic fluids of maghemita were prepared and afterwards they were employed in the silica-coating procedures which were based on the Stöber method. Some experimental parameters were varied, such as the number of maghemita nanoparticles, pH of the reaction medium, time of reaction and amount of TEOS, with the aim of modulating the characteristics of the solids and obtaining stable aqueous suspensions of the materials. All products were analyzed by the following techniques: X- ray diffraction, diffuse reflectance infrared spectroscopy, dynamic light scattering, electrophoretic mobility (zeta potential) and transmission electron microscopy.
Estudo cristaloquímico do 2-(2-tienil) -1,3 benzotiazol: polimorfos orientacionais com alto Z’ e co-cristalização com calix[4]tubo
(Universidade Federal de Goiás, 2019-02-12) Alvarenga, Meiry Edivirges; Martins, Felipe Terra; http://lattes.cnpq.br/0466799995060671; Martins, Felipe Terra; Gomes, Danielle Cangussu de Castro; Chagas, Rafael Pavão das
This work the first time a cocrystal of the so-called neutral calix[4]tube, that is two tail-to-tail arranged and partially deprotonated tetra(carboxymethoxy)calix[4]arene molecules including three sodium ions, with 2-(2-thienyl)-1,3-benzothiazole, which means a new approach into host-guest chemistry of inclusion complexes. Three packing polymorphs of the same benzothiazole with high Z’ (one with Z’ = 8 and two with Z’ = 4) were also discovered in the course of our desired cocrystallization. The inspection of these polymorphs and another previously known one with Z’ = 2 revealed that Z’ increases as the strength of intermolecular contacts decreases. By the discovery of the polymorphs the theoretical study of the intermolecular interactions was realized to understand the evolution of the value of Z’. Also, these results expand the frontier of invoking calixarenes as host for non-solvent small molecules, besides adding knowledge to the rare formation of high Z’ packing polymorphs of simple molecules as the target benzothiazole.
Ressonância Magnética Nuclear e quimiometria como ferramentas de distinção e quantificação de metabólitos de cana-de-açúcar (Saccharum officinarum) e feijão-comum (Phaseolus vulgaris)
(Universidade Federal de Goiás, 2010-06-11) ALVES FILHO, Elenilson de Godoy; ALCANTARA, Glaucia Braz; http://lattes.cnpq.br/6408676855110487; LIÃO, Luciano Morais; http://lattes.cnpq.br/2647529909397336
Five different common beans cultivars (Phaseolus vulgaris) in the raw conditions, after water immersion (soaking) and after domestic processing (cooking), were studied by NMR in solution and HR-MAS NMR, to obtain a protocol that quantify the oligosaccharides raffinose, stachyose and verbascose contents in bean seeds. The looking for low contents of these oligosaccharides in bean seeds is inserted in Embrapa Arroz e Feijão objectives. This study describes yet the potentiality of chemometric analysis applied in 1H HR-MAS NMR and in solution NMR for investigation of sugarcane varieties. Sugarcane is a primordial material used in Brazil for production of ethanol biofuel. Several technologies to development of new sugarcane cultivars have mainly focused the increase of productivity and greater disease resistance. Sugarcane cultivars are usually identified by organography of leaves and stems, as well as the analysis of peroxydase and esterase isoenzyme activities, soluble total protein and soluble solids content. In this work eight different cultivars of sugarcane leaves were analyzed: RB72454, RB835054, RB835486, RB855113, RB855156, RB855453, RB855536 and RB867515. NMR and chemometric analysis showed useful tools for distinction of the different sugarcane cultivars. In addition, these techniques successfully demonstrated the chemical differences about the investigated cultivars, specially the sugar contents.
Incorporação de nanopartículas de ferrita de cobalto (CoFe2O4) em resina epoxídica para a obtenção de nanocompósitos
(Universidade Federal de Goiás, 2016-10-18) Alves Júnior, Eli Silveira; Franco Júnior, Adolfo; http://lattes.cnpq.br/0187547195548392; Sartoratto, Patrícia Pommé Confessori; http://lattes.cnpq.br/9777959525393785; Sartoratto, Patrícia Pommé Confessori; Franco Júnior, Adolfo; Caiado, Kely Lopes; Nunes, Liliane Magalhães
Nanocomposites based on magnetic nanoparticles dispersed in a polymer matrix has emerged as a new class of materials that might be applied in various technology segments, such as telecommunication, aerospace and recently biomedical industry. However, obtaining nanocomposites with uniform distribution of nanoparticles in the polymeric matrix has been a challenge due to the chemical incompatibility between these materials. In this context, the objective of this study was to evaluate the homogeneity of the dispersion of cobalt ferrite (CoFe2O4) nanoparticles in an epoxy resin matrix by varying the method of incorporating them into the polymeric matrix (by adding a powder or a colloidal dispersion of nanoparticles). The prepared materials were evaluated by chemical (FTIR, AA, UV-Vis), structural (XRD), thermal (TG, DSC), morphological (DLS, SEM, TEM) and magnetic (VSM) characterization techniques. A strong correlation between the method of incorporation of the cobalt ferrite nanoparticles, the uniformity of their dispersion into the polymeric matrix and the thermal and magnetic properties of the nanocomposites was verified.
Estudo estrutural por 1h-rmn de peptídeos bioativos isolados da secreção cutânea de Hypsiboas Albopunctatus E Leptodactylus Labyrinthicus
(Universidade Federal de Goiás, 2012-02-24) ALVES, Eliane Santana Fernandes; LIÃO, Luciano Morais; http://lattes.cnpq.br/2647529909397336
Currently, the emergence of fungi, bacteria and viruses resistant to multiple drugs has stimulated interest in the development of antimicrobial peptides with increased therapeutic potential. They generally have properties of extreme importance as antimicrobial selective toxicity, rapid action, specific mechanisms of action and a broad spectrum of antimicrobial action. Many of these features can be found in peptides isolated from frog skin secretions. The main factor that differentiates antimicrobial peptides from other commonly antibiotics used in the conventional therapy is related to their mechanism of action. The driving force for much of the action of antimicrobial peptides is their ability to lysis cell membranes, rapidly killing a broad spectrum of microorganisms. Accordingly, the conformation of the peptide has a great importance in their interaction with the amphiphilic structure of biological membranes. The determination of the tridimensional structure by Nuclear Magnetic Resonance (NMR) technique allows the identification of the spatial position of each amino acid residue and highlighting those that are important for its action and, therefore, could be modified to increase the antimicrobial activity. The study of the three-dimensional structure of peptides in solution is an advantage of the NMR spectroscopy, since it can simulate the physiological environment, by means of surfactants. In this context, the tridimensional structures of two synthetic peptides: ocellatin-P1G16 (GLLDTLKGAAKNVVGGLASKVMEKL-NH2), isolated from the amphibians Leptodactylus labyrinthicus, and hylin a1 (IFGAILPLALGALKNLIK-NH2), isolated from Hypsiboas Albopunctatus, were proposed by NMR. The amphipathic caracter can be visualized by separation of the helix into two distinct sides, one hydrophobic (nonpolar) and the other hydrophilic (polar). The peptide hylin a1 in presence of SDS-d25 showed helical structure between residues Ile-5 to Ile-17 and the peptide ocellatin-P1G16 in SDS-d25 micelles showed a α-helical structure between residues Leu-3 to Lys-24, both are presented in amphipathic α-helix Finally, the molecular analyses of amphipathicity, electrostatic interaction, polarity and exchange hydrogen/deuterium, corroborate the proposed model, suggesting a model of parallel orientation to the peptide hylin a1 and the peptide ocellatin-P1G16 a parallel orientation, but with the cterminal portion immersed in the micelle SDS-d25 between residues Ser-19 to Leu-25, as observed by analyzing exchange hydrogen/deuterium. These structural characteristics make these peptides promising candidates for the development of a new antimicrobial drug.
Estudo por ressonância magnética nuclear da estrutura e interação de novos protótipos de biofármacos antimicrobianos
(Universidade Federal de Goiás, 2016-04-18) Alves, Eliane Santana Fernandes; Oliveira, Aline Lima de; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4772309D7; Lião, Luciano Morais; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4721165A6; Almeida, Fábio; Resende, Jarbas Magalhães; Flavia, Kátia; Lião, Luciano Morais; Kato, Lucília
Antimicrobial peptides are gaining high importance in the pharmaceutical sector given its high affinity and selectivity to interact with targets, and its low toxicity profile. The increase in the number of peptides screened in clinical trials is a significant triumph for structural biology, considering the search for peptides that meet the required criteria in terms of cost, stability, long half-life and bioavailability. This research is best performed with a good understanding of the mechanisms of action, dynamics and biomolecules kinetics. Nuclear magnetic resonance spectroscopy (NMR) plays an important role in this context, since it provides informations about the interactions in target binding solution of biologically active molecules. Thus, this study aims to observe the intramolecular interactions of peptides clavanin A, Cm-p1 and [Phe3]Cm-p1. The clavanin peptide is found in tunicate blood cells Styela clava, and presents a broad spectrum of activity against Gram-positive and Gram-negative bacteria, and against several kinds of fungi. The Cm-p1 peptide can be extracted from the crude extract of the marine snail Cenchritis muricatus, and shows activity against yeasts and filamentous fungi. The peptide [Phe3]Cm-p1 corresponds to Cm-p1 peptide modified with a change in residue position 3. Circular dichroism spectroscopy was used in the observation of secondary structure of peptide, and the informations provided by NMR were used in the studies of molecular modeling. The clavanin peptide in the presence of TFE (2,2,2-trifluoroethanol), presented a amphipathic alpha-helices from Phe-2 to Val-22 residues. The Cm-p1 peptide was structured in α-helix, short amphipathic, in the presence of micelles of SDS-d25 between Arg-2 and Ile-6 residues. The peptide [Phe3]Cm-p1 in the presence of micelles SDS-d25 (sodium dodecyl sulfate) is structured between Arg-2 and Gln-9, showing that the addition of a hydrophobic residue in position 3 provided a greater interaction peptide-micelle, as noted by the smaller diffusion of the peptide [Phe3]Cm-p1 relative to Cm-p1 peptide. All the obtained structures showed good quality and geometry, as revealed by the validation study. NMR spectroscopy provided information about the intramolecular interactions of peptides clavanin A, Cm-p1 and [Phe3]Cm-p1. It was possible to assign the residues which were important in the interactions between the peptides and the environment. This knowledge is essential in the development of new drugs.
Síntese, caracterização e estudo das propriedades magnéticas do Zn1-xFexO (0,00 ≤ x ≤ 0,09) produzido por reação de combustão
(Universidade Federal de Goiás, 2010-11-25) ALVES, Thiago Eduardo Pereira; FRANCO JÚNIOR, Adolfo; http://lattes.cnpq.br/0187547195548392
In this work compounds Zn1-xFexO, with 0.00 ≤ x ≤ 0.09, were synthesized by combustion reaction method with two different heating processes, in a thermal blanket and muffle furnace. Chemical analysis of compounds was performed by atomic absorption spectroscopy (AAS) and Fourier transform infrared (FTIR). Structural analysis of the crystalline phase, the diameter of the crystallites and the lattice parameters were checked by X-ray diffraction (XRD, powder method) and refinement software (Unitt and powder X cell). The analysis of surfaces and morphologies were determined by adsorption and desorption of N2 (ASAP, BET model) and transmission electron microscopy (TEM). Finally, Magnetic measurements were performed by vibrating sample magnetometer (VSM). The stoichiometric determined by atomic absorption is in good agreement with the calculated value for all samples. The samples were synthesized in a thermal blanket which corresponds to the wurtzite crystal structure with no secondary phases. The samples synthesized in furnace had wurtzite crystal structure, however, showed a small sample to phase segregation above 5%. The second phases are found with spinel phase indicate that the formation of zinc ferrite. The data of thermal analysis, infrared and X-ray diffraction, we show that the synthesis product in blanket form moving slowly in several stages, while that in the synthesis furnace gets the product directly. We noted the tendency of the formation of smaller particles for the samples from the thermal blanket, as well as high surface areas for these samples, those prepared in a muffle grating. Images by transmission electron microscopy confirm the observations made by x-ray diffraction measurements of surface areas by BET model. The magnetic measurements show ferromagnetic phenomenon only for the sample produced in a muffle. The saturation magnetization was calculated by extrapolation, and their values are promising when compared with the literature. The Curie temperatures were estimated for some samples and all values were well above room temperature.
Síntese, caracterização e estudo das propriedades magnéticas e ópticas de óxidos nanoparticulados: CoFe2-xYxO4 produzido por reação de combustão e ZnO produzido por meio do método poliol
(Universidade Federal de Goiás, 2018-07-18) Alves, Thiago Eduardo Pereira; Franco Júnior, Adolfo; http://lattes.cnpq.br/0187547195548392; Franco Júnior, Adolfo; Pessoa, Márcio Solino; Araújo, Olacir Alves; Lima, Emília Celma de Oliveira; Sartoratto, Patrícia Pommé Confessori
n this study we investigated the structural, optical band-gap, and magnetic properties of CoFe2-xYxO4 ) nanoparticles (NPs) synthesized using a combustion reaction method without the need for subsequent heat treatment or the calcing process. The particle size measured from X-ray diffraction (XRD) patterns and transmission electron microscope (TEM) images confirms the nanostructural character in the range of 16–36 nm. The optical band-gap (Eg) values increase with the Y3+ ion concentration being 3.30 and 3.58 eV for x = 0,00 and x = 0,04, respectively. The presence of yttrium in the cobalt ferrite (Y-doped cobalt ferrite) structure affects the magnetic properties. For instance, the saturation magnetization, MS and remanent magnetization, Mr, decrease from 69 emu.g-1 to 33 and 28 to 12 emu.g-1 for x = 0,00 and x = 0.04, respectively. On the other hand the coercivity, Hc, increases from 1100 to 1900 Oe for x = 0,00 and x = 0,04 at room temperature. Also we found that MS, Mr, and Hc decreased with increasing temperature up to 773 K. The cubic magnetocrystalline constant, K1, determined by using the ‘‘law of approach’’ (LA) to saturation decreases with Y3+ ion concentration and temperature. K1 values for x = 0,00 (x = 0,04) were 3,3 x 106 erg.cm-3 (2,0 x 106 erg.cm-3) e 0,4 x 106 erg.cm-3 (0,3 x 106 erg.cm-3) at 300 K and 773 K, respectively. The results were discussed in terms of inter-particle interactions induced by thermal fluctuations, and Co2+ ion distribution over tetrahedral and octahedral sites of the spinel structure due to Y3+ ion substitution. Also, in the present work, zinc oxide (ZnO) nanoparticles were prepared by the polyol method which consist of zinc acetate acetate and sodium acetate in propylene glycol solution with control over the hydrolysis reaction time and subjecting to the variation of reaction parameters, as ratio of hydrolysis (th) and ratio of acetate (ta). It was observed that the reaction time of the hydrolysis and the addition of ions had a strong effect on the morphology and size of the ZnO particles. For example, transmission electron microscopy (TEM) images revealed that the ZnO samples were synthesized for short time of RH (10 min) and long time (300 min) in small rods and in elongated rod forms, respectively. On the other hand, using only zinc acetate reagent, as the ZnO samples crystallized into a coarse spherical shape. These differences can be attributed to the polarization of the acetate and the propylene glycol, i.e., the greater amount of deficits present in the preferred growth solution of the ZnO crystals. In addition, the HR time does not change changes in the optical band gap. For example, values controlled by the Kubelka-Munk model decreased from 3.31 eV to 3.28 eV for the short HR time and the long HR time, respectively. This can be explained in terms of defects and is due to the change in particle sizes. X-ray diffraction patterns (XRDs) revealed that all the units crystallized the typical wurtzite structure of ZnO. However, the relative intensity of the diffraction peak (002) of the ZnO samples was synthesized with zinc acetate and was higher than the sensations from zinc acetate as sodium acetate. That is, an indication of direction should be directed toward the preferential growth of the crystals. Therefore, the morphology of the ZnO samples can be adapted using the polyol method, just as the physical properties are important for some technological applications.
Estudos sobre a educação para as relações étnico-raciais e a descolonização do currículo de química
(Universidade Federal de Goiás, 2017-07-26) Alvino, Antônio César Batista; Benite, Anna Maria Canavarro; http://lattes.cnpq.br/8433607360245647; Benite, Anna Maria Canavarro; Dias, Luciene de Oliveira; Souza, Lorena Francisco de
This study suggests the debate on the Decolonization of the Chemistry curriculum considering that America is a continent that had its social formation and culture founded on slave labor (Native Americans and Africans), the school as a microcosm of this society, in its curricula, also omits these presences. We argue that the best possible education is the one that ensures the rights of all (colonizers and colonized). However, the Brazilian school curriculum prioritizes the culture of the colonizer; in other words, the teaching of chemistry is based on European culture. The research proposes a curriculum that is committed to developing students' potentialities, understanding the organization, transformations, structure and properties of the matter and to understand the complex social and racial reality of Brazil. The objective of this research is to reconsider the teaching of chemistry by performing an epistemic displacement of the Chemistry curriculum. The empirical results presented in this text were collected in an Experimental Chemistry class that focuses on the Decolonization of the curriculum. This class had the purpose of making the epistemic displacement of the Chemistry curriculum working within the topic of the Law 10.639/03. Empirical results of three pedagogical interventions developed in the class are presented, eight excerpts from the discourse produced (biofuels, global warming, bleaching ideology, surface tension and body cleaning) are presented according to the topic of each class. The results show possibilities of teaching Chemistry from an epistemic matrix that is not European. The results indicate the need to think about the relationship between the construction of chemical knowledge and the social and racial relations within the classrooms and how they favor student development.
Hidrocalcogenação de derivados de álcoois propargílicos mediados por calcogenolatos de zinco
(Universidade Federal de Goiás, 2014-02-28) Andrade, Floyd Custódio Diniz; Barros, Olga Soares do Rego; http://lattes.cnpq.br/8311808341863723; Kato, Lucilia; http://lattes.cnpq.br/1362891438631386; Barros, Olga Soares do Rego; Kato, Lucilia; Chagas, Rafael Pavão das; Cunha, Rodrigo Luiz Oliveira Rodrigues
Organylzinc chalcogenolate mediated hydrochalcogenation of propargyl alcohols organylzinc chalcogenolate (chalcogen = sulfur, selenium and tellurium) prepared from the reductive cleavage of diorganyl dichalcogenide bonds by the Zn/NH4OH system led to organylzinc chalcogenolates that provide an alternative synthetic route to produce carbon-chalcogen bonds. This work presents new synthetic methodology and discusses the general aspects and limitations of organylzinc chalcogenolate to promote the hydrochalcogenetion of 2-alkyn-1-ol derivates leading mainly the Markovnikov allylic alcohols bearing a vinylic chalcogenide substituints. We investigated the chemo, regio- and stereoselctivity for this protocol in two different systems: in aqueous medium and in organic medium.
Tratamento químico de poluentes emergentes da indústria cosmética utilizando materiais de baixo custo
(Universidade Federal de Goiás, 2019-09-06) Andrade, Pryscilla Martins de; Brito, Núbia Natália de; http://lattes.cnpq.br/9075769086344855; Ionashiro , Elias Yuki; Arruda , Andréa Fernandes; Brito, Núbia Natália de
The cosmetics industry presents a variety of products that contain numerous organic structures, which once in contact with water, release effluents with low biodegradability, high organic load, high levels of suspended solids, fats and oils. These effluents, when subjected to conventional (isolated) treatment at sewage treatment plants, based mainly on microbiological degradation, are not treated efficiently, leaving significant concentrations of emerging pollutants at the end of the treatment. As an alternative for effluent treatment from the cosmetics industry, advanced oxidation process (AOP) treatment technologies, which involve the generation of hydroxyl radical (•OH), with a 2.8 V potential redox, are interesting because present mineralization capacity of organic matter. Among them, the photo Fenton Like process is promising, as it has as its differential the feasibility of harnessing solar energy as a source of radiation and the utilization of by-products from the steel/metallurgical industry, besides providing the lowest generation of sludge. In this work, the photo Fenton Like treatment was proposed for the cosmetic effluent, using as source of iron, metallurgical residue, and as radiation source, light-emitting diode lamps (LED) and the construction of a recirculating photocatalytic reactor. An integration of technologies was proposed as the final polish using a filter built with layers of agro-industrial waste (rice husks, vermiculite and carbonized corn cob). The acid-washed metallurgical residue had about 96% iron oxide III in its composition, confirming its viability for the application of the heterogeneous photo Fenton Like process. Under the conditions of metallurgical residue with acid wash (HCl) in dosage of 8 g L-1, H2O2 in 0.05 g L-1, effluent with pH 3.0 adjustment and time of 6 minutes, the advanced oxidative treatment provided 99.25% chemical oxygen demand removals and 75.73% total organic carbon. Thermogravimetric analysis of the chemical sludge revealed the presence of 14% by mass of organic matter in the metallurgical residue, indicating that most of the organic matter present in the cosmetic matrix was oxidized. Infrared spectroscopy analysis found that the small amount of material adsorbed and possibly related to paraffin. With the combined process, advanced oxidation by heterogeneous photo Fenton Like and slow filtration, it was possible to achieve an overall removal of 99.48% COD with a final value of 255.98 mgO2 L-1, which meets the required state parameters for disposal in water sources. Through these results, the integration of the treatment technologies proved to be satisfactory for the remediation of this recalcitrant matrix, since high removal of the organic matter parameter values was achieved, which may be indicative of the possibility of integration with the treatment technologies conventional.
Síntese, otimização e avaliação da atividade biológica de derivados de chalconas
(Universidade Federal de Goiás, 2015-06-19) Anjos, Murilo Machado dos; Oliveira, Guilherme Roberto de; http://lattes.cnpq.br/8239498431579015; Oliveira, Guilherme Roberto de; Matos, Ricardo Alexandre Figueiredo de; Perez, Caridad Noda
The world's population sees aging and some diseases that become more common. Alzheimer's disease (AD) is a dementia caused by loss of cognitive function of the individual and drugs used in their treatment is based on the inhibition of the enzyme acetylcholinesterase (AChE). Cancer is a group of diseases that develop due to the disorderly proliferation of cells may be related to genetic factors as well as dietary habits and exposure to radiation, the treatment being based on three main techniques: surgery, radiation and chemotherapy. In this work we synthesized 15 compounds (11 chalcones and 4 imines), based on the condensation of Claisen-Smth, and they are characterized by NMR (1H and 13C), IV These compounds were submitted to acetylcholinesterase activity by the modified method of Elman, using CCD and Martson, in addition to the evaluation of cytotoxic tumorias lines SF-295 (glioblastoma - human), HL-60 (acute leukemia promielítica) and HCT-116 (colon). The compounds showed no activity for the enzyme AChE front of the methods employed, and this cause investigated using molecular modeling methods, which sought in the literature active compounds for this enzyme, containing resemblance with the structures synthesized in this work. 80 descriptors were calculated being submitted to statistical analysis (Fisher's weight) where the number of variables is reduced to 24 and these have been selected GAP and bond angle where it was observed that the values of the synthesized compounds, mostly It was found out of range for the active compounds. The previous modeling studies are not sufficient to determine the causes of inactivity of the compounds, being necessary to the realization of a structure and reactivity studies. The evaluation of the antitumor compounds presented become more positive as the MCH-1
Remoção de compostos ácidos do petróleo em diferentes tipos de carvão ativado
(Universidade Federal de Goiás, 2016-02-29) Araújo, Anderson Barros Caixeta; Vaz, Boniek Gontijo; Ostroski, Indianara Conceição; http://lattes.cnpq.br/9689394915288313; Ostroski, Indianara Conceição; Vaz, Boniek Gontijo; Oliveira, Emília Celma de; Romão, Wanderson
The naphthenic acids comprise a complex mixture of carboxylic acids that are present in petroleum. They are directly responsible for the oil acidity and its corrosiveness in liquid phase during the refining process. Such compounds are also presents in the derivatives, causing several problems to product quality. A possible way of removing these acids from those oil fractions is using the adsorption process in porous solids, as activated carbons. There are few studies about the removal of naphthenic acids on coals. For this reason, we chose four types of activated carbons for adsorption tests, and they coal babassu, palm kernel, coconut and of Bahia ox bone. In order to assess the possibility of further removing acidic compounds, the four carbons were subjected to a chemical treatment with concentrated sodium hydroxide. Physical and chemical analyzes were performed in order to promote the characterization of all adsorbents, showing that the treatment previously mentioned was leading to an increase in the adsorption capacity of the coals. The adsorption experiments with commercial batch naphthenic acid solution showed that the treated ox bone char had the highest retention efficiency, which is the adsorbent used to construct the adsorption isotherms. The isotherms were better adjusted by Langmuir model, revealing the chemisorption of character adsorptive process. The thermodynamic data showed that the process is spontaneous and endothermic, is favored by increasing the temperature. Regarding the crude oil sample, batch adsorption experiments were conducted in such a way as to determine the removal efficiency of class O2 and reducing the Total Acid Number (IAT). The results spectrometry FTICR ix MS Pasta, they showed that all coals chemically treated were able to remove more acidic compounds in relation to their untreated related. The raw coals babassu oil, palm oil and coconut Bahia showed a potential for adsorption of nitrogen compounds from oil, given that there was a decrease in its class in the class chart. As a final analysis, all the coals were evaluated for their ability to lower oil IAT, it was found that the ox bone char treated again achieved the best result, reducing by 70% the value of the IAT.
Estudo da determinação de ácido ascórbico em solução utilizando eletrodo de carbono vítreo modificado com Nafion®
(Universidade Federal de Goiás, 2017-03-28) Araújo, Kelly Rejane de Oliveira; Colmati Junior, Flávio; http://lattes.cnpq.br/0231242349462585; Colmati Junior, Flavio; Angelucci, Camilo Andrea; Arruda, Andrea Fernandes
This work was developed with the objective of determining the oxidation profile of ascorbic acid in solution using cyclic voltammetry, square wave voltammetry and differential pulse voltammetry, observing the oxidation behavior due to the increase in the concentration of ascorbic acid in solution using In the electrochemical measurements, a carbon-modified glass-carbon electrode and Nafion®, a polymer widely used in electrochemical analysis. The experiments had an emphasy on standard ascorbic acid analysis, but were also performed with vitamin C tablets of different trade marks, obtaining in both a significant increase of the anodic peak currents coming from the oxidation of the ascorbic acid, resulting from a good stability Of the modified working electrode. For comparison purposes with the Nafion®-modified glass carbon electrode, standard ascorbic acid analyzes were also performed with the use of the vitreous carbon electrode. With the results of the analysis it was possible to determine the mass of ascorbic acid found in vitamin C tablets, from the construction of an analytical curve, in which it presented the necessary parameters for this. By varying the scanning velocities of the analyzes by cyclic voltammetry, it was possible to find out when plotting the current x square root velocity graphs by which process the oxidation of ascorbic acid on the electrode surface would occur. The electrochemical experiments with standard ascorbic acid showed the oxidation behavior by varying the pH of the phosphate buffer solution, evidencing the best pH range to work using the Nafion® modified glass carbon electrode. The use of square wave and differential pulse voltammetry techniques allowed to now the profile of the oxidation of ascorbic acid in vitamin C tablets, demonstrating a better sensibility in the peak current signal by the use of differential pulse voltammetry.
Licenciaturas em Química do IF Goiano: concepções e influências no contexto formativo
(Universidade Federal de Goiás, 2016-08-03) Aves, Dylan Ávila; Mesquita, Nyuara Araújo da Silva; http://lattes.cnpq.br/6971106875143413; Mesquita, Nyuara Araújo da Silva; Felício, Cinthia Maria; Souza, Aparecido Ribeiro de
The deficit of teachers in the country throughout the history of Brazil is due to many factors and among them the low expectations for the teaching profession presented by young Brazilians, especially in the areas of Exact Sciences, contributed to the Federal Government to establish from the law No. 11,892 / 08, the Federal Institutes (IF) should allocate 20% (twenty percent) of the budget funds for degree courses and teacher qualifications. The state of Goiás currently has two IF, the IFG and the IF Goiano, each institution has five chemistry degree courses created from the year 2008. In this study we sought to analyze the training context in degree courses in Chemistry IF Goiano and used as research objects courses Pedagogical Project (PPP) of the five undergraduate programs of the institution, in order to analyze the professional profile sought this in the documents built by the members of each campus, and also use the "voices "the licentiate in chemistry obtained from questionnaires, to seek the views and perspectives imposed on teacher training. Analyses signaled that although undergraduate courses, direct courses for teacher training with the technological bias and the formation of structure has a trodden direction in the training model by technical rationality. This model can interfere in the professional profile to be formed in the IF Goiano, which can approach the bachelor's degree programs. This distortion in the formation may possess intrinsic relationship with the habitus set of IF Goiano, which compromises the teacher training of future teachers, in order not to become autonomous and reflective teachers. is denoted by the voices of licensees, that the teaching profession is not the first option after completing the course and end up choosing to work in industries, laboratories, other areas, or end up postponing the educational performance when enrolling in graduate school and this lack of perspective may be related to the lack of incentive and encouragement in their own courses. The survey also allowed us to analyze the implicit concepts in PPC interfere with the type of teacher training not targeted by the survey, able to exercise it in the educational field, with a survey of the overlap of the chemical field, which contributes to the misconception with relation to the training model of the teacher, which is a professional performer of routine activities, not using research as a tool towards a transformative education.
Otimização da produção de biodiesel metílico a partir de óleos de fritura residuais (OFR)
(Universidade Federal de Goiás, 2014-05-09) Azeredo, Weine Amorim; Antoniosi Filho, Nelson Roberto; http://lattes.cnpq.br/5982964870999454
Waste frying oils (WFO) consist an environmental liability, whose use in biodiesel production of adequate quality is compromised due to poor quality of the raw material. High levels of free fatty acids, degradation products of fatty acids, peroxides, hydroperoxides, metal and large amount of water in the feedstock compromise the quality of biodiesel produced. So the use of liquid-liquid extraction (LLE) as a pretreatment of the WFO using water as the solvent showed an efficient method in reducing the levels of polar compounds. After the OFR pre-treatment with water partition followed by the removal of the absorbed water via distillation under reduced pressure, experimental designs have been performed in steps acid esterification and transesterification alkaline thereby obtaining biodiesel samples with high contents methyl ester (96-98%). For the purification of biodiesel from WFO, the use of adsorbents such as silica and alumina proved efficient in the removal of water and reduction the acidity of the biodiesel, however reduced the oxidative stability. Distillation of biodiesel proved effective in reducing the water content, although reduced the oxidative stability of biodiesel.
Síntese e caracterização de nanocompósitos de ferrita de cobalto/carvão ativado à partir de copolímeros de estirenodivinilbenzeno sintetizados com óleo de soja
(Universidade Federal de Goiás, 2014-03-11) Barbosa, Carolina Freire; Barbosa, Danns Pereira; http://lattes.cnpq.br/4085399124895999; Rabelo, Denilson; http://lattes.cnpq.br/4961539278604455; Oliveira, Sérgio Botelho de; http://lattes.cnpq.br/3447406257464639; Martins, Felipe Terra; http://lattes.cnpq.br/0466799995060671
In this work, activated carbon beads were prepared through carbonization of styrene-divinylbenzene (Sty-DVB) copolymers synthesized in the presence of soybean oil as diluent and cobalt ferrite nanoparticles dispersed in the organic phase. Firstly, a cobalt ferrite gel was prepared through co-precipitation technique with posterior surfactant action by oleic acid. The copolymer and the composites containing cobalt ferrite were obtained through suspension polymerization. Four matrixes were obtained, which have the following differences: the cobalt ferrite content (2 or 5 %), the amount of hydroxyethylcellulose used in the synthesis and the realization or not of a purification step before thermal treatments. Soybean oil was chosen as diluents in order to evaluate its effects on the synthesized materials considering the polymerization possibility due fat acid unsaturations and its low volatility. All synthesized materials were characterized by the following analysis: DRX, FTIR, TGA, nitrogen adsorption measurements (specific surface area, pore volume and pore size distribution), MEV and catalytic activity in the ethyl-benzene dehydrogenation reaction. Further, the composites had metal content evaluate by AAS. The soybean oil and the ferrite gel had a strong influence on the textural properties of copolymers and their respective activated carbons. All obtained activated carbons were active in relation to ethylbenzene dehydrogenation reaction. However, the activated carbon obtained from pure copolymer, i.e., without cobalt ferrite, presented the highest specific surface area, catalytic activity and selectivity. This catalyst also had the best stabilization of catalytic properties during evaluated reaction time.

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