Potassium ion transport processes across the interface of an immiscible liquid pair in the presence of crown ethers

Abstract

The mechanism of potassium ion transfer from an aqueous to a 1,2-dichloroethane phase which is facilitated by urushiol crown ether or dibenzo-18-crown-6 in the range of potassium concentrations, c K + , from 0.1 m M to 1 M was studied by current scan polarography at the ascending water electrode, chronopotentiometry, and chronopotentiometry with current reversal at the stationary water electrode. At c K + below 0.02 M a single polarographic wave is obtained, which corresponds to the transfer of K + -crown ether complex from the aqueous phase. At c K + ≥ 0.02 M , an additional wave appears at a less positive potential which grows at the expense of the first wave, which finally disappears at higher c K + . The second wave results from the transfer of a simple potassium ion across the interface, where it reacts with the crown ether. At c K + at which the additional wave begins to appear, the formation reaction of K + -crown ether takes place at the aqueous side of the interface.