Formation of complexes of potassium and sodium cations with dicyclohexano-18-crown-6, dibenzo-18-crown-6 and cyclohexano-15-crown-5 over a temperature range of 2° to 38°C

The percent extraction of potassium and sodium ions from aqueous solution has been measured for DC18C6, DB18C6 and C15C5 dissolved in methylene chloride as a function of temperature. The percent extraction was found to decrease as the temperature increased. For the binary mixture of potassium and sodium ions, synergestic effects appeared. These synergestic effects become pronounced as the temperature increases Also distribution coefficients were measured and observed to follow the same behavior with temperature. Selectivity for DC18C6 and DB18C6 is higher at room temperature (25°-30°C) for potassium over sodium ions Initial concentrations were kept constant during the whole course of experiment, only the effects of ions, ring size, and ring structure were investigated.