Papers by Geormenny Rocha dos Santos
Engenharia de Produtos Naturais: planejamento, experimentação, obtenção de produtos e purificação, 2021
Modelos termodinâmicos capazes de predizer dados de equilibrio sao indispensaveis na sintese e pr... more Modelos termodinâmicos capazes de predizer dados de equilibrio sao indispensaveis na sintese e projeto de plantas e de processos quimicos, pois pode ser observado, com muita frequencia, que poucos ou nenhum dado experimental estao disponiveis a custos acessiveis para as misturas a serem consideradas. Neste sentido, este trabalho teve como objetivo desenvolver uma nova versao do modelo UNIFAC (Universal Quasi Chemical Functional-Group Activity Coefficient) para calculo do coeficiente de atividade capaz de predizer dados de equilibrio liquido-liquido e avaliar o desempenho deste metodo em representar tais dados de equilibrio em substituicao aos modelos de contribuicao de grupo tradicionais. As modificacoes apresentadas para o modelo UNIFAC consistem em: (1) utilizar uma nova forma para o termo combinatorial, eliminando a correcao de Staverman-Guggenheim; (2) fazer escolha criteriosa dos grupos funcionais com base em calculos quânticos ab initio (grupos-abinitio) Os parâmetros de volum...
Journal of Chemical & Engineering Data, 2017
Data on the liquid–liquid equilibrium (LLE) for the systems water + [2–HEA][Pr], [2–HEA][Bu], and... more Data on the liquid–liquid equilibrium (LLE) for the systems water + [2–HEA][Pr], [2–HEA][Bu], and [2–HEA][Pe] + 1-pentanol were determined at 293.15, 313.15, and 333.15 K and atmospheric pressure. Phase diagrams of the ternary systems were determined using the turbidimetric titration method and the tie-lines were quantified using the gravimetric method. Othmer–Tobias correlation confirms the quality of the experimental LLE data (R2 > 0.95). The NRTL (nonrandom two-liquid) and UNIQUAC (universal quasichemical) models were used to predict LLE data, with satisfactory results of root-mean-square deviations (RMSD) of each model at 1.55 and 1.90%, respectively.
Fluid Phase Equilibria, 2010
ABSTRACT Ternary liquid–liquid equilibria (LLE) data in systems involving ionic liquids has been ... more ABSTRACT Ternary liquid–liquid equilibria (LLE) data in systems involving ionic liquids has been investigated by several years, mainly due to the innovative role of ionic liquids as extraction solvents. The thermodynamic modeling of these systems has been performed almost invariably with the well-known NRTL model. In recent years, the UNIQUAC model has also been used, with structural parameters for ionic liquids determined either by empirical correlations or, more recently, through quantum mechanics calculations. In this work, the structural group volume and area parameters for the group-contribution UNIFAC method have been calculated for six ionic liquids following the quantum mechanics approach. The Density Functional Theory (DFT) was used to optimize the molecular geometry and the Polarizable Continuum Method (PCM) was used to calculate the area and volume. The obtained parameters were used to correlate LLE data for twenty-four ternary systems, totalizing 169 tie-lines. New interaction parameters were also estimated between the solvent and ionic liquid functional groups. The results are very satisfactory, with root mean square deviations between experimental and calculated compositions about 1.6%.
Fluid Phase Equilibria, 2010
In this work, new UNIQUAC structural parameters r and q for the ionic liquids were determined by ... more In this work, new UNIQUAC structural parameters r and q for the ionic liquids were determined by quantum chemistry calculations performed with the Gaussian 03 and GAMESS 7.1 packages, including the density functional theory (DFT) for the optimization of the structures and the polarizable continuum method (PCM) for the calculation of molecular areas and volumes. Data liquid–liquid equilibrium (LLE) of
Engenharia de Produtos Naturais: planejamento, experimentação, obtenção de produtos e purificação, 2021
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Papers by Geormenny Rocha dos Santos