Navegando por Autor "Teixeira, Ana Paula de Carvalho"
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Item Alcoxycle : a novel route for glycerol reform into H2 and COx inseparate stages.(2016) Paula, Fabiano Gomes Ferreira de; Rosmaninho, Marcelo Gonçalves; Teixeira, Ana Paula de Carvalho; Souza, Patterson Patrício de; Lago, Rochel MonteroIn this paper, it is proposed a new route, named “Alkoxycle”, for the conversion of glycerol from biodieselproduction into H2and CO/CO2in different and separate stages. In this process, glycerol first reacts withNaOH to form an alkoxide that, in a second step, undergoes controlled thermal decomposition. Analysesof glycerol:NaOH precursor mixtures (molar ratios of 1:1, 1:2, 1:3 and 1:5) by TG, XRD, SEM, TEM, Raman,total carbon and GC–MS showed that the decomposition of the alkoxide at 400◦C leads to the formationof three fractions: liquid, gas and solid. The liquid products were formed only in very small amountswhereas an important gas fraction (12–16 wt%) was produced consisting mainly of H2(95% selectivity).In the second stage, the solid products (70–86 wt%) consisting of Na2O, carbon and mostly Na2CO3canbe decompose by heating at 700◦C to procuce CO2and especially CO. At the end of the Alcoxycle process,the NaOH used in the reaction and also the NaOH present in the biodiesel glycerol can be recovered andreused.Item K2MgSiO4 : a novel K+-trapped biodiesel heterogeneous catalystproduced from serpentinite Mg3Si2O5(OH)4.(2016) Ballotin, Fabiane Carvalho; Cibaka, Thérèse Ebambi; Benfica, Tatiana Aparecida Ribeiro dos Santos; Santos, Eleonice Moreira; Teixeira, Ana Paula de Carvalho; Lago, Rochel MonteroIn this study, a new catalyst for biodiesel synthesis, based on K2MgSiO4, was produced from the mineralserpentinite. TG, SEM, XRD, AA, BET analyses showed that serpentinite Mg3Si2O5(OH)4impregnated withKOH (5,10 and 20 wt%), and thermally treated at 500◦C, 700 and 900◦C, can be converted to the main crys-talline phase K2MgSiO4. Analyses by TPD-MS (CO2) and titration suggested the presence of weak/mediumbasic sites in relatively high concentrations. Biodiesel production using soybean oil (methanol:soybean oilratio of 1:12, 1:9; 1:6, 60◦C) showed yields higher than 95% with catalyst at 10 wt%, which can be reusedfor three consecutive times without significant decrease on the reaction yield. The obtained results arediscussed in terms of a new catalytic phase based on K+ions trapped in the cavities of the MgSiO42−structure containing negatively charged oxygen basic sites.Item New heterogeneous catalyst for the esterification of fatty acid produced by surface aromatization/sulfonation of oilseed cake.(2015) Santos, Eleonice Moreira; Teixeira, Ana Paula de Carvalho; Silva, Flávia Gontijo da; Cibaka, Thérèse Ebambi; Araújo, Maria Helena; Oliveira, Willian Xerxes Coelho; Medeiros, Felipe; Brasil, Alex Nogueira; Oliveira, Leandro Soares de; Lago, Rochel MonteroIn this work, an efficient heterogeneous acid catalyst for the esterification of oleic acid was prepared directly from oilseed cake by a simple sulfonation with concentrated H2SO4. Characterization by SEM/EDS, IR, Raman, TG, TG/MS, potentiometric titration showed that treatment with H2SO4 for 1, 2 and 4 h at 120 _C partially dehydrates the cake to form a carbon/cellulose composite which is sulfonated to produce strong ASO3H acidic sites. These surface sites were active for the esterification of oleic acid with yields ca. 84%, 88% and 94% in the presence of 5, 10 and 20 wt% catalyst, respectively. These results are comparable to 98% yield obtained with 1 wt% H2SO4 and higher than 75% observed for a high surface area (880 m2 g_1) sulfonated activated carbon with similar number of ASO3H active groups. These results are discussed in terms of two effects: (i) the number of sulfonic surface acidic groups and (ii) the presence of a hydrophilic cellulosic fraction in the catalyst that adsorbs/traps water formed in the reaction shifting the esterification equilibrium and improving the yield.Item Production of fuels via thermal decomposition of copper oleates from CuO.(2020) Luciano, Vivian A.; Perígolo, Deise Morone; Rosmaninho, Marcelo Gonçalves; Teixeira, Ana Paula de CarvalhoIn this work, the thermal decomposition of copper carboxylates formed from CuO and different proportions of oleic acid and CuO was used to produce liquid and gaseous fuels. These reactions gave rise to solid, liquid and gaseous fractions that were studied by different techniques, such as XRD, TG, Raman spectroscopy, FTIR, SEM, TEM, NMR and GC–MS. The liquid fraction obtained was the largest, made up mainly of oleic acid, i.e., the starting reagent was regenerated in the reaction. The gas fraction was the second largest, consisting mainly of hydrogen gas, with selectivity above 80%. The solid fraction was the smallest but showed the formation of metallic copper, carbon and copper(I) oxide. This work showed that it was possible to produce materials from acid oils and metal oxides that, after being thermally decomposed, generated gas fuels of great industrial interest, as well as metal phases, and the regeneration of the acid used as the starting reagent.Item Thermal cracking of oleic acid promoted by iron species from iron ore tailings for the production of ketones and fuels.(2022) Luciano, Vivian Andrade; Paula, Fabiano Gomes Ferreira de; Pinto, Paula Sevenini; Prates, Caroline Duarte; Pereira, Rafael César Gonçalves; Ardisson, José Domingos; Rosmaninho, Marcelo Gonçalves; Teixeira, Ana Paula de CarvalhoIron ore tailings (IOT) are rich in iron oxides and silica and can be used for different applications such as allow the thermal cracking of fatty acids for the production of fuels and products with high added value. Thus, this work aimed to use of IOT as an iron source for the production of high-value products using oleic acid (OA) as carbon sources. These compounds were produced from a thermal decomposition reaction, from the mixture of OA and IOT, in a high pressure reactor (12.5 bar), using the ratio of 1:1 wt (acid:IOT), in temperatures between 250 and 450 ◦C (3 and 12 h). The results showed that for all reactions, the solid products obtained showed a percentage of less than 6 % of carbon material and different iron phases (Fe2O3, Fe3O4 and FeOOH). For the reactions carried out at 250 and 350 ◦C/3h the main fraction obtained was the liquid, however the compostion was mainly the starting compound and iron oleate. For the reactions carried out at 400 and 450 ◦C/3h, the main fraction was gas, mainly hydrogen. For the reaction carried out at 350 ◦C for 12 h the mass balance showed the formation of similar amounts of liquid and gaseous products. Liquid products formed ketones as the main product, while gaseous products were identified and presented greater selectivity for C3 hydrocarbons.