Leon S. Scott

Determination of activity coefficients by accurate measurement of boiling point diagram

Abstract Scott, L.S., 1986. Determination of activity coefficients by accurate measurement of boiling point diagram. Fluid Phase Equilibria 26: 149–163. An improved technique has been developed for the rapid and accurate measurement of the boiling point diagram of binary mixtures in and out of the infinite dilution region. The data can be used to calculate activity coefficients in the infinite dilution region and over the entire composition range.

Selective separation of valeric acid from dibasic acids using supercritical carbon dioxide

Abstract Separations of coproduct valeric acid from mixed dibasic acids is essential for a new process of producing adipic acid for nylon production. The batch fractionation of valeric acid from mixtures of valeric acid and dibasic acids consisting of methyl glutaric acid and ethyl succinic acid was carried out with su percritical carbon dioxide using a continuous flow saturation apparatus. Phase equilibria of valeric acid and mixtures of valeric acid with methyl glutaric acid with supercritical carbon dioxide were measured in the range 35–65 °C and 68–140 bar. Apparent equilibrium of a mixture of valeric acid, methyl glutaric acid, and ethyl succinic acid with carbon dioxide is also reported. A high-pressure view-cell allowed visual observation of the number of phases present. Results indicate that highly selective removal of valeric acid is possible from the mixtures of dibasic acids using supercritical carbon dioxide at 50 °C and 90 bar, with loadings of valeric acid close to 0.1 mol %. Solubility of valeric acid in the fluid phase was increased to almost 6.5 mol % at 50 °C and 138 bar but with a decrease in the selectivity for valeric acid. The data obtained were correlated using the Peng-Robinson equation with conventional quadratic mixing rules.

Modeling multicomponent equilibria from binary equilibrium data for reacting systems

Abstract Although direct phase equilibria measurements of reacting systems are difficult to obtain generally, the thermodynamic behavior of a reacting system such as that found in a reactive distillation processes can be constructed indirectly from measurements involving the phase equilibria of nonreacting pairs of compounds involved in the reaction in combination with an activity coefficient model. The binary data are used to regress binary interaction parameters for the chosen activity coefficient model. The ternary phase equilibria are estimated from the model. This work will describe the application of this method to the reactive system water/3-pentenoic acid/methyl-3-pentenoate. Vapor-liquid and liquid-liquid equilibrium measurements for the binary components were used to fit NRTL and UNIQUAC parameters. These activity coefficient models were then used to show how the composition-phase behavior can be constructed for the ternary system from the binary information only.