Improving prediction of salt effect on vle of isopropyl alcohol‐h₂o‐salt and methanol‐h₂o‐salt systems with preferential association

Abstract

When a salt is added to an azeotropic mixture, the azeotropic composition tends to shift or even disappear, due to salt-in and salt-out effects. Models from the literature are applied to calculate the vapor-liquid equilibrium of systems of isopropyl alcohol H, O-salt, and methanol H,O-salt. Schmitt and Vogelpohl's model (1982) gives the best results. With the concept of preferential association, an improvement can be accomplished through the modified distribution factor of the salt associating with components of the mixture for the systems mentioned above.Owing to the lack of solubility data of the salt in the individual components of the azeotropic mixture, the generality of this modification has not yet been demonstrated.Lorsque du sel est ajoutt ?I un mklange azkotrope, la composition azkotrope tend 2 se dCcaler ou m&me ?I disparaitre, en raison des effets de salage et de relargage. Les modbles parus dans la littkrature sont appliquks pour calculer I'Cquilibre vapeur-liquide des systhes d'alcool isopropyl-H,O-sel et mttanol-H,O-sel. Le modble de Schmitt et Vogelpohl (1982) donne les meilleurs rksultats. Avec le concept de l'association prkfkrentielle, on peut obtenir une amklioration par le facteur de distribution modifiC du sel s'associant avec les autres composants du mtlange pour les systbmes mentionnks ci-dessus.En raison de I'absence de donntes sur la solubilitk du sel dans chacun des composants formant le mklange azkotrope, on n'a pas encore pu dkmontrer le caractltre gknkral de cette modification.Keywords: salt effect, vapor-liquid equilibria, ternary VLE, preferential association.istillation plays a very important role in the separation

Vapor−Liquid Equilibrium of Propan-2-ol + Propan-1-ol + Sodium Iodide at 298.15 K

“…For a binary mixture containing an electrolyte, the expression for the normalized excess Gibbs energy in the system becomes The activity coefficients of both solvents in the system are given by The Wilson parameters between solvent i and salt 3 are simply assumed to be given by Measured vapor-liquid equilibrium data for the ternary system were correlated using Ha ´la's equation. In this work, the exponent β value was treated as a parameter (Kumagae et al, 1992;Lee et al, 1991), and the optimized β value was determined using the vapor-liquid equilibrium data of the ternary system. The parameters in Ha ´la's equation and the accuracy of this calculation are presented in Table 5, and the calculated values are illustrated by the full line in Figure 2.…”

“…Especially, the effect of electrolytes on phase equilibria has been utilized in many equilibrium separation processes (Furter, 1977). However, these VLE data are scarcely measured and few investigations on the effect of salt have been published (Hongo et al, 1989Mishima et al, 1987;Kumagae et al, 1992Kumagae et al, , 1993Lee et al, 1991).…”

Vapor−Liquid Equilibria for Alcohol + Alcohol + Sodium Iodide at 298.15 K

“…Ha ´la (1983) proposed a semiempirical model using a value of β of 3 / 2 . For some systems, the difference between Ha ´la's parameter and the experimental value was as much as 20% (Lee et al, 1991). Recently, Mishima (1987) proposed that β be treated as a parameter.…”

“…The apparatus is based on a static method (Kojima, 1969;Iino et al, 1971;Lee et al, 1991). The schematic diagram is shown in Figure 1.…”

Liquid−Liquid Equilibria of the Benzene + Water + Acetic Acid Ternary System and Solubility of Benzene in Water: Effect of Calcium Chloride

“…The salt effect on vapor-liquid equilibria has also been found to be useful in dealing with azeotropic mixtures. 11,12 Though the salting-out effect has been observed for many years, it has not been explored particularly for practical applications in wastewater treatment. Sutton and Calder 13 studied the solubilities of some high molecular weight paraffins in distilled water and seawater.…”