| abstract |
Sterically hindered nitrogen bases of the general formulae I and II <IMAGE> in which R1-R4 each represent hydrogen or alkyl having up to 20 C atoms, optionally bound to a polymeric carrier, and X represents hydrogen, alkyl, alkoxy, alkylthio, alkanoyloxy, alkyl- or arylamino or -sulphonamido having, in each case, up to 20 C atoms, optionally bound to a polymeric carrier, can be used as selective complexing agents for isolating noble metals from aqueous solutions. |