Navegando por Orientadores "SANTOS, Geormenny Rocha dos"

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Acesso aberto (Open Access)
Determinação de propriedades termofísicas e estudo do equilíbrio líquido-líquido de sistemas envolvendo líquidos iônicos próticos
(Universidade Federal do Pará, 2017-03-24) GOMES, Rossimar dos Santos; SILVA, Silvana Mattedi e; http://lattes.cnpq.br/8741124364246075; SANTOS, Geormenny Rocha dos; http://lattes.cnpq.br/0844662601945669
This work consisted of the synthesis of protic ionic liquids (Ethyl 2-hydroxyethylammonium propionate [E2HEAP][PR], Diethylammonium propionate, [DEA][PR] and Butylammonium propionate, [BA][PR] and determination of density and viscosity of protic ionic liquids [DEA] [PR] and [BA] [PR] pure and the binary systems formed by these ionic liquids + water at different temperatures and atmospheric pressure. The density data were determined using a digital densimeter and viscosity by the viscometer, both of Anton Paar, the experimental results were used to obtain excess molar volume (𝑉𝑚𝐸), apparent molar volume (𝑉∅,1), viscosity deviation (Δη) and excess Gibbs free energy (ΔGE), being the results correlated with the Redlich-Kister or Redlich-Meyer equation. The results were compared and discussed based on the molecular interactions between the studied componentes. It was also made the study of liquid-liquid equilibrium data (LLE) for systems, involving 1-butanol + water + protic ionic liquids: [E2HEA][PR] or [DEA][PR] or [BA][PR] K and atmospheric pressure, being the systems quantified by the gravimetric method. The quality of the equilibrium data was verified by the semi-empirical methods of Othmer-Tobias and Hand. From the obtained equilibrium data, the values of the distribution coefficient found indicated the hydrophilic behavior of the LIs studied. Data liquid–liquid equilibrium was correlated by the NRTL and UNIQUAC thermodynamic models, which was observed that the NRTL model correlated in a more satisfactory way the results presenting global deviation of 1,56% for NRTL and 1,78% for UNIQUAC.
Acesso aberto (Open Access)
Equilíbrio líquido-líquido dos sistemas biodiesel de castanha do Brasil + metanol + (glicerina ou água): determinação experimental e modelagem termodinâmica
(Universidade Federal do Pará, 2013-12-18) GONÇALVES, Jefferson Dias; AZNAR, Martín; http://lattes.cnpq.br/5798321645560791; SANTOS, Geormenny Rocha dos; http://lattes.cnpq.br/0844662601945669
Biodiesel is defined as being a mixture of fatty esters derived of animal fats or vegetable oils, obtained through the process of transesterification with short chain alcohols. During the production is used a quantity in excess of alcohol and a catalyst to propitiate the formation reaction of esters; in this way the output flow of the reactor contains the catalyst, the unreacted alcohol and products obtained by transesterification, biodiesel and glycerin, forming a biphasic system; depending on the solubility of these compounds, will may there be amounts of biodiesel and glycerin-rich phase and quantities of glycerin in biodiesel-rich phase. During the process of purification of biodiesel it is necessary to accomplish a washing with water, to promote removal of the catalyst and impurities of the product of interest. Due to the amount of compounds involved in the production and purification is essential to know the liquid-liquid equilibrium data in order to predict the proportions in which the compounds coexist and subsequently, to proceed with purification under suitable conditions for obtaining biodiesel with greatest efficiency and to assist in the design of the reactor and tanks. The objectives of this work were to produce biodiesel from oleaginous plants native to the region, the Brazil nut (Bertholletia excelsa H. B. K.) and to establish liquid-liquid equilibrium data (ELL) to ternary systems: biodiesel of Brazil nut + methanol + glycerin and biodiesel of Brazil nut + methanol + water at temperatures of 30° C and 50° C. The biodiesel produced was initially characterized in accordance with the standards of the National Petroleum Agency (ANP) using physicochemical methods. The data obtained were afterward correlated with NRTL and UNIQUAC thermodynamic models for the calculation of the coefficient of activity of each component in the liquid phase, with new energetic interaction parameters obtained. The results obtained from the modeling were satisfactory, and was observed that the NRTL model represented better the experimental data.
Acesso aberto (Open Access)
Extração de antocianinas do açaí (Euterpe oleracea) em sistemas aquosos bifásicos formados por etanol e sulfato de amônio
(Universidade Federal do Pará, 2017-03-07) LAGO, Adriane Rosário do; CORRÊA, Nádia Cristina Fernandes; http://lattes.cnpq.br/5763999772352165; SANTOS, Geormenny Rocha dos; http://lattes.cnpq.br/0844662601945669
Euterpe oleracea is a plant species that occurs naturally in the Amazon region, known as açaí. Its fruit is considered a functional food due to the high content of phenolic compounds, mainly anthocyanins, which gives the fruit high antioxidant power. In addition, it presents high nutritional value presenting in its composition fibers, proteins, vitamins and minerals. In this study the technique of extraction by Aqueous Two-Phase System (ATPS) was applied to the study of the partition of the anthocyanins present in the aqueous extract of açaí. The alcoholic extract of açaí was used to study the stability of anthocyanins in different solutions of salts and alcohol, where the extract had 718.32 mg/L of anthocyanins. ATPS were prepared with ammonium sulfate, ethanol and water at 25 and 35 ° C. In the process of extraction of anthocyanin by ATPS was verified the effect of pH, temperature and time of extraction. The best anthocyanin extraction condition was pH 3.4 at 33 °C for 30 min. The best partition coefficient obtained was 2.70, indicating the affinity of the compound studied for the top phase of ATPS. The extraction process used in this study was more efficient than the conventionally used analytical quantification technique for anthocyanin extraction.
Acesso aberto (Open Access)
Partição de antocianinas de açaí utilizando equilibrio líquido-líquido a base de solventes eutéticos profundos
(Universidade Federal do Pará, 2021-02-04) SABOYA, Adriana Marcela Moreno; COSTA, Mariana Conceição da; http://lattes.cnpq.br/5415527829271587; SANTOS, Geormenny Rocha dos; http://lattes.cnpq.br/0844662601945669
The anthocyanin in the acai fruit is one of the most attractive industrial compounds. It is used as a natural dye due to its violet pigment and its antioxidant power. An alternative technique for the extraction of biomolecules is extraction using Liquid Liquid Equilibrium (LLE) systems, composed of Deep Eutectic Solvents (DESs) characterized by being economical, efficient and of low toxicity to the environment and human body. Therefore, this study aimed to determine liquid-liquid equilibrium data of DES-based systems: ChCl:GLI (choline chloride:glucose) + isopropanol + water and ChCl:SAC (choline chloride:saccharose) + isopropanol + water at temperatures of 25oC and 35oC, and to assess its application in the partition of the acai anthocyanins. First, the physical-chemical characterization of the lyophilized acai was carried out. Second, Box Behnken factorial design was applied to analyze and optimize the extraction process to evaluate the influence of experimental conditions on the extraction of anthocyanin and total polyphenols from the lyophilized acai. Once the optimization conditions were found, the DESs that would be used in the LLE system were prepared. Furthermore, the thermal and structural properties for each DESs were determined with DSC and FTIR respectively. Third, aiming to research DESs behavior with water and isopropanol mixtures in equilibrium phases, the LLE data at 25 oC and 35oC were determined. The binodal curves were obtained by cloud point titration, and the tie lines were determinate for gravimetrical and analytical (HPLC and Karl-fischer) methods. The systems studied were characterized as quaternary systems and the experimental LLE data were correlated by NRTL obtaining a mean quadratic deviation (RMSD) of 0.438%. The anthocyanin partition in ELL was carried out using the anthocyanin extract obtained in optimal conditions. Finally, it was proven that the individual components of DESs have a high affinity with the anthocyanins, showing the total migration of the biomolecules in the bottom phase. The partition coefficients of total polyphenols (KPT) were higher than 1, showing the preference of biomolecules in the bottom phase and the extraction efficient (%EE) of 70% with ChCl + Glucose + isopropanol + water system. This result confirmed xithe potential of using these systems to extract natural pigments aiming at a probable use of the separation of nonpolar biomolecules (acai lipids) in the alcohol-rich phase.