Preferential adsorption of protium and deuterium oxides from solutions of diethyl ether and ethyl acetate on a sodium ion exchanger

Isotherms for the adsorption of H2O and D2O from solutions of diethyl ether and ethyl acetate on a sodium resinate at 298.15 K were determined as well as the activity curves of the two waters in these solvents. H2O is adsorbed in larger mol amounts than D2O, but in low D2O concentrations the measurements were disturbed by a slow hydrogen exchange between D2O and the resin matrix. Corrected to activity scale, the isotherms in both solvents are nearly identical. They resemble also the isotherms obtained for adsorption from gas phase, but with smaller slopes at low water activities due to smaller heats of swelling of the resin in liquid phase. The results fit well the two parameter BET isotherm at low activities. The Gibbs energy change of the resin swelling, ΔG=-16500 J/(mol of the resin), is somewhat lower in absolute value than in gas phase. According to the isotherms ion exchange resins are potential agents for dehydration of certain organic liquids. (author)