Equilibrated Vapor Concentrations for Bicomponent Organic Solvents

Equilibrated Vapor Concentrations for Bicomponent Organic Solvents: Hajime HORI, et al. Department of Environmental Management I, School of Health Sciences, University of Occupational and Environmental Health, Japan— The equilibrated vapor concentrations for bicomponent organic solvents of toluene–o-xylene, methanol– toluene and methanol–o-xylene mixtures were measured at various compositions. The equilibrated vapor concentration of each component for the toluene–o-xylene system was almost proportional to its liquid phase molar fraction. For the methanol– toluene and the methanol–o-xylene systems, however, methanol vapor occupied 80–90% of the total organic vapor in the gas phase, even the molar fraction of methanol in the liquid phase was less than 5%. For the toluene–o-xylene system, because the solution was regarded as an ideal solution, the equilibrated vapor concentrations could be estimated from the saturated vapor concentrations of pure solvents and their liquid molar fractions. On the other hand, the methanol– toluene and the methanol–o-xylene systems could not be regarded as ideal solutions. For these systems, the equilibrated vapor concentrations could be estimated by introducing the activity coefficients calculated with the Margules equation. (J Occup Health 1998; 40: 132–136)