Browsing by Author "Foco, Gloria"
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- Extension of UNIFAC to associating systemsPublication . Foco, Gloria; Ferreira, Olga; Brignole, Esteban A.; Bottini, Susana B.An extended UNIFAC group contribution model for the prediction of activity coefficients in associating mixtures was presented recently (Mengarelli et al.,1999). In the present work the model is applied to solutions containing alcohols, water, carboxylic acids and inert components. The residual UNIFAC local composition term is re-parameterized in order to take into account only dispersive forces between associating and inert functional groups. Good representation of vapor-liquid and liquid-liquid equilibrium, as well as infinite dilution activity coefficients is achieved by using a single set of group interaction parameters.
- Group contribution modeling of activity coefficients in associating solutions containing water, alcohols and carboxylic acidsPublication . Ferreira, Olga; Orge, Beatriz; Foco, Gloria; Bottini, Susana B.A modified UNIFAC group contribution model for the prediction of activity coefficients in associating solutions (A-UNIFAC) is applied to calculate phase equilibria in binary and ternary mixtures of associating and non-associating species, including alcohols, water, carboxylic acids, esters, alkanes, aromatic hydrocarbons and alkyl chlorides. Self- and cross-association in these mixtures is adequately described by the definition of a single hydrogen-bonding group. The new model is able to give good predictions of vapor-liquid equilibria, liquid-liquid equilibria and infinite dilution activity coefficients, using a single set of group-interaction parameters.
- Infinite dilution activity coefficients of solvents in fatty oil derivativesPublication . Ferreira, Olga; Foco, GloriaInverse gas-liquid chromatography has been applied to measure infinite dilution activity coefficients (γ∞) of different solutes in low and high molecular weight triacylglycerides (TAGs) and in mixtures of carboxylic acids with TAGs. The γ∞ data obtained were used to determine binary interaction and size related parameters for the GCA-EOS group contribution with association equation of sate.