SORPTION AND DIFFUSIVITY MEASUREMENTS OF CYCLOHEXANE PLUS BENZENE ANDCYCLOHEXENE PLUS TOLUENE MIXTURES IN POLYURETHANE MEMBRANES - MODEL-CALCULATIONS OF THE PERVAPORATION PROCESS

Data of vapor sorption measurements of the solvents cyclohexane, benze ne and toluene in polyurethane (PU) membranes are presented. Vapour so rption isotherms have been obtained from equilibrium data. Kinetic sor ption data have been used for determining diffusion coefficients of th e solvents in the membrane material. Further measurements of the indiv idual solubilities of liquid cyclohexane+benzene and cyclohexane+tolue ne mixture components in PU-membrane material have been carried out us ing the so-called swelling density method and a gaschromatographic ana lytical method. Vapor sorption isotherms as well as solubility data of the liquid mixtures can be described with the UNIQUAC-model in good a greement with experiments. All results obtained for solubilities and d iffusion coefficients are used for predictive calculations of fluxes a nd separation diagrams in the pervaporation process of cyclohexane + b enzene and cyclohexane + toluene mixtures through PU-membranes. The ba sis of these model calculations is the solution-diffusion model. Predi cted results of pervaporation agree well with experimental data taken from literature provided diffusion coupling of the components permeati ng the membrane is taken into account.