Geraldo N. da Rocha Filho

Determination of the oxidative stability by DSC of vegetable oils from the Amazonian area

Differential scanning calorimetry (DSC) and a Rancimat method apparatus were applied to evaluate the oxidative stability of buriti pulp oil (Mauritia flexuosa Mart), rubber seed oil (Hevea brasiliensis), and passion fruit oil (Passiflora edulis). The Rancimat measurements taken for the oxidative induction times were performed under isothermal conditions at 100°C and in an air atmosphere. The DSC technique involved the oxidation of oil samples in an oxygen-flow DSC cell. The DSC cell temperature was set at five different isothermal temperatures: 100, 110, 120, 130 and 140°C. During the oxidation reaction, an increase in heat was observed as a sharp exothermic curve. The value T(0) represents the oxidative induction time, which is determined from the downward extrapolated DSC oxidative curve verses the time axis. These curves indicate a good correlation between the DSC T(0) and oxidative stability index (OSI) values. The DSC method is useful because it consumes less time and less sample.

Conversion of waste produced by the deodorization of palm oil as feedstock for the production of biodiesel using a catalyst prepared from waste material.

The distillate produced by deodorization of palm oil (DDPO) is a waste that corresponds to 4% of the product formed in this process. DDPO is 83% free of fatty acids (FFA), making it a good material for biodiesel production. In this paper, a catalyst prepared from a waste material, Amazon flint kaolin, was used for the esterification of DDPO with methanol. Leached metakaolin treated at 950°C and activated with 4M sulfuric acid (labeled as MF9S4) offered maximum esterification activity (92.8%) at 160°C with a DDPO:methanol molar ratio of 1:60 and a 4-h reaction time. The influences of reaction parameters, such as the molar ratio of the reactants, alcohol chain length, temperature, time and the presence of glycerides and unsaponifiable matter, have also been investigated. Based on the catalytic results, esterification of DDPO using MF9S4 can be a cheaper alternative for production of sustainable fuels.

Effect of cerium loading on structure and morphology of modified Ce-USY zeolites

Este trabalho descreve detalhadamente o efeito da quantidade de cerio na estrutura e morfologia da zeolita NH4USY. Ce-USY (2-25% m/m de CeO2) foi obtido por impregnacao umida de CeCl3 seguida de calcinacao a 550oC por 8 h. Em quantidades baixas (2-10%), foi observado que as especies de cerio encontram-se nas posicoes de troca ionica na rede, enquanto em maiores teores (15-25%) pequenos agregados formaram-se na superficie da HUSY. Difratometria de raios X (XRD) mostrou apenas reflexoes relacionadas a HUSY, confirmando a alta dispersao das especies de cerio, porem as analises por espectroscopia Raman com transformada de Fourier (FT-Raman) detectaram CeOx para os materiais acima de 10%. A reacao do CeCl3 com NH4USY produziu NH4Cl, o qual se decompoe em HCl, ocasionando a desaluminizacao da rede. Os materiais apresentaram um aumento da razao Lewis/Bronsted com o aumento da quantidade de cerio, devido a interacao do excesso de cerio com os grupos OH da USY e consequente formacao de especies CeOx.

Characterization, thermal properties and phase transitions of amazonian vegetable oils

Thermal profiles of buriti pulp oil (Mauritia flexuosa Mart.), tucumã pulp and kernel oils (Astrocarium vulgare Mart.), rubber seed oil (Hevea brasiliensis), passion fruit oil (Passiflora edulis) and ucuúba butter (Virola surinamensis) were analyzed by thermogravimetry (TG/DTG) and differential scanning calorimetry (DSC). Gas chromatography and calculated iodine values were performed to determine the fatty acid profile and to measure the degree of unsaturation in these oils, respectively. The TG curves showed three steps of mass loss, which can be attributed to the degradation of polyunsaturated, monounsaturated and saturated fatty acids. The DSC crystallization and melting curves are reported and depended on the fatty acid composition. Usually, oil samples with a high degree of saturation showed crystallization and melting profiles at higher temperatures than the oils with a high degree of unsaturation. The data obtained by physicochemical analysis of oil samples were analyzed by principal component analysis and hierarchical cluster analysis to increase understanding of the data set, examining the presence or absence of natural groupings between samples.

Soybean biodiesel methyl esters, free glycerin and acid number quantification by 1H nuclear magnetic resonance spectroscopy.

Production of alternative fuels, such as biodiesel, from transesterification of vegetable oil driven by heterogeneous catalysts is a promising alternative to fossil diesel. However, achieving a successful substitution for a new renewable fuel depends on several quality parameters. 1H NMR spectroscopy was used to determine the amount of methyl esters, free glycerin and acid number in the transesterification of soybean oil with methanol in the presence of hydrotalcite‐type catalyst to produce biodiesel. Reaction parameters, such as temperature and time, were used to evaluate soybean oil methyl esters rate conversion. Temperatures of 100 to 180 °C and times of 20 to 240 min were tested on a 1 : 12 molar ratio soybean oil/methanol reaction. At 180 °C/240 min conditions, a rate of 94.5 wt% of methyl esters was obtained, where free glycerin and free fatty acids were not detected. Copyright

Ethanolysis optimisation of jupati (Raphia taedigera Mart.) oil to biodiesel using response surface methodology.

In this work, the transesterification of jupati (Raphia taedigera Mart.) oil using ethanol and acid catalyst was examined. The production of biodiesel was performed using a central composite design (CCD). A range of values for catalyst concentration (1 to 4.21%), temperature (70-80 °C), and the molar ratio of alcohol to oil (6:1-13.83:1) were tested, and ester content, viscosity, and yield were the response variables. The synthesis process was optimised using response surface methodology (RSM), resulting in the following optimal conditions for the production of jupati ethyl esters: a catalyst concentration of 3.85% at 80 °C and an alcohol-to-oil molar ratio of 10:1.

Functionalization of Bentonite and Vermiculite after the Creation of Structural Defects through an Acid Leaching Process

The synthesis and use of functionalized materials is growing every year. Thus, this work presents a methodology for the functionalization of bentonite and vermiculite after the acid leaching of the raw materials. Leaching was performed with sulfuric acid (H2SO4), and the functionalization was performed with (3-mercaptopropyl)trimethoxysilane (MPTS), which was oxidized after being anchored to the support. Compared to the results in the literature for directly functionalized raw bentonite, the materials had a greater number of anchored propyl sulfonic acid groups, and the greatest number of these groups led to an increase in the acidity of the raw materials. The raw and functionalized bentonite and vermiculite were characterized by X-ray diffraction (XRD), energy dispersive X-ray (EDX), thermogravimetric analysis (TGA), N2 adsorption and the surface acidity was determined by acid-base titration.

Determination of biodiesel properties based on a fatty acid profile of eight Amazon cyanobacterial strains grown in two different culture media

The primary source of biodiesel obtainment in Brazil is concentrated in oleaginous vegetables, especially soy. However, there is a great hold-up caused by competition with the food industry, which makes the search for alternative pathways that do not compete with other industries needed. The goal of this study was to investigate the biotechnological potential of cyanobacteria, which were grown in two different culture media, as an alternative approach for obtaining biodiesel. For this purpose, Microcystis aeruginosa CACIAM03, CACIAM08, Synechocystis sp. CACIAM05, Lyngbya sp. CACIAM07, Cyanobium sp. CACIAM14, Leptolyngbya sp. CACIAM18, Limnothrix redekei CACIAM25 and Planktothrix pseudoagardhii CACIAM27 were evaluated. Fatty acid composition was determined using gas chromatography. Fatty acids found in all strains were identified as palmitic acid (C16:0) (7.43–38.37% content), stearic acid (C18:0) (1.44–13.82%), caproic acid (C6:0) (0.82–78.84%) and oleic acid (C18:1) (1.13–46.76%). The biodiesel quality parameters were calculated based on the fatty acid profile. Strains that showed the best values and provided better biodiesel quality were Synechocystis sp. CACIAM05 and Microcystis aeruginosa CACIAM03 that were grown in BG-11 medium. This study showed us a promising source of biodiesel production from cyanobacterial lipids based on empirical calculations of the parameters of biodiesel quality that met the fuel standards. Furthermore, our results suggest the production of fatty acids through a metabolic route, due to the change in the profile of fatty acids in both culture media, providing valuable information for future engineering to increase the percentage of fatty acids that give better biodiesel quality.

Síntese de éster de cadeia longa via catálise básica heterogênea

Um ester de cadeia longa foi sintetizado pela transesterificacao do palmitato de metila com alcoois de cadeia longa usando oxido de magnesio como catalisador. Esses foram preparados pela decomposicao termica de diferentes precursores, buscando estabelecer relacoes entre propriedades estruturais e atividades. Temperatura e quantidade de catalisador foram variados para se avaliar o rendimento do ester em funcao do precursor utilizado na preparacao do oxido.