Isothermal vapor-llqukl equlllbrlum data were determlned by using a Boubllk-Benson still for the p-dloxane-acetonitrile system at 298.15 K. The results obtained were correlated in terms of the llqukl activity coeffklents of the two components by two-sufflx Margules and van Laar eauatlons.Vapor-liquid data are necessary for interpretation of distiktion processes. Thi s paper reports the resutts of measurements on vapor-liquid equilibrium for the pdioxane-acetonitrile system at 298.15 K. Experimental data for this system have not been reported in the literature, and this system was chosen because pdioxane (component 1) is nonpolar and acetonitrile (component 2) is polar.
Experimental SectionAcetonitrile (Carlo Erba p.a.) was distllled over dried P205 at reduced pressure, and only the middle half of each distillation was recovered. paioxane (Baker p.a.) was distilled over sodium at reduced pressure, and again only the middle half of each distillation was recovered.Densities were determined with a Robertson specific gravity bottle. The refractive indexes for the sodium D line of the pure components were measured with a Jena dipping refractometer with an accuracy of fO.OOO 02.Equilibrium data were determined by using a modified version of the equilibrium still described by Boublii and Benson ( 7). The still and a water ebulloscope were attached to a large pressure vessel which could be maintained at any required pressure. The equilibrium value of the pressure was calculated from the boiling point of water in the ebulloscope. The latter could be determined with an accuracy of 0.01 OC by using a calibrated thermometer. The temperature in the still was also measured at 0.01 OC. Barometric pressure and room temperature were recorded for each experimental run, and necessary corrections were made on the observed pressure values. Compositions of the equilibrium liquid and condensed vapor phases were obtained from measurements of their refractive indexes at 298.15 K by using eq 1 ( Z ) , where x1 is the molar fraction of pdioxn,(x,) = 0.93925~' + 0.76097(1x,) + xl(lxi) X [-0.21520 -0.28471(2X, -1) -0.43586(2X1 -I)'] (1) ane. This equation correlates the results of a series of known composition mixtures of the two components.Table I gives densities, refractive indexes, and vapor pressures of the pure components and literature values for comparison. 0021-9568/81/1726-0020$01 .OO/O Table I. Physical Properties of Pure Components at 298.15 K P n D Po compd exptl lit.= exptl lit.= exptl lit.
Isothemral vapor-liquidequilibria (VLE) formixtures containing 2-pmpanol * tehahy-drofi¡ran * I-cñIorobutane have been measured using ¿ utodified version of a Boubük-Benson still at 25" C. A test of thermodynamic consistency, like t*e McDermott*Ellis methodwas applied to the activitycoefficients-Excess molar Gibbs free energies were calc¡rlated ov €r tfte vrtire range composition" DifFerent expressions existing in t{re literatufe wer€ used to predict activity coefficients-KEY WORDS: Vapor{iquid equilibrfum; binary and bmary systems; excess molar free energies; activity coefficients.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.