Palladium(II) extraction by N,N '-dipentylethylenediamine-N '-thiocarbaldehyde from hydrochloric acid solutions

Palladium(II) extraction at 25 degreesC by N,N'-dipentylethylenediamine-N'- thiocarbaldehyde (L) from HCl solutions was studied. An extraction equilibr ium is found to be established within one minute. The metal ion is extracte d from 0.5 M HCl solutions (with toluene or chloroform as a diluent) by the ion-exchange-solvation mixed mechanism in the form of the complex cis-PdCl 2(L . HCl)(2) given an excess extractant (Pd : L less than or equal to 1 : 2). At higher palladium(II) concentrations, cis-[PdCl2(L . H)(2)][PdCl4] is separated as a third phase from extracts in the case of extraction by L to chloroform, and trans-[PdCl2(L . H)(2)][PdCl4], in the case of extraction by L to toluene. Thermodynamic parameters and apparent concentration consta nts of extraction were determined.