Effect of solvent in competitive alkali metal cation transport across bulkliquid membranes by a lipophilic lariat ether carboxylic acid carrier

Fluxes and selectivities for competitive alkali metal cation transport acro ss bulk liquid membranes by the lipophilic crown ether carboxylic acid carr ier sym-(octyl)dibenzo-16-crown-5-oxyacetic acid have been determined in a variety of chlorinated hydrocarbon and aromatic hydrocarbon solvents. The m embrane solvents include: dichloromethane, chloroform, carbon tetrachloride , 1,2-dichloroethane, 1,1,1-trichloroethane, o-dichlorobenzene, toluene and p-xylene. The total alkali metal cation and Na+ fluxes, as well as the Na/K+ and Na+/Li+ transport selectivity ratios, are compared with selected pr operties of these organic solvents using the Schmidt, Swain, Koppel-Palm an d Kamlet-Taft models. The best correlations are obtained for the Na+ flux a nd the Na+/K+ transport selectivity. (C) 1999 Elsevier Science B.V. All rig hts reserved.