SELECTIVITY IN THE EXTRACTION OF COPPER(II) WITH A NEW ALKYLATED 8-QUINOLINOL DERIVATIVE WITH A NITROPHENYLAZO SUBSTITUENT

The extraction behavior of Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Ga(III), and Cd(II) was studied with a new chelating extractant, (5-4-nitrophenylazo)-7-(4-ethyl-1-methyloctyl)-8-quinolinol (HNEQ), in chloroform. HNEQ exhibits a much higher extractability for Co(II), Cu(II), Zn(II), and Cd(II) than 8-quinolinol. Especially, Cu(II) was quantitatively extracted with 0.001 mol dm-3 of HNEQ at such a low pH as 2.0 within 15 min, and was readily separated from the other metal(II, III) ions studied. From equilibrium studies. the extracted Cu(II)-HNEQ chelate was ascertained to be Cu(NEQ)2. The extraction constant (log K(ex)) was determined to be 4.25, which was much larger than those for 7-(4-ethyl-1-methyloctyl)-8-quinolinol (Kelex 100) and 8-quinolinol.