SYNERGISTIC EXTRACTION OP CADMIUM AND ZINC FROM NITRATE MEDIUM WITH 3-PHENYL-4-BENZOYLISOXAZOL-5-ONE IN THE PRESENCE OF METHYL-TRI-n-OCTYLAMMONIUM NITRATE IN CHLOROFORM AND TOLUENE

The synergistic extraction of cadmium and zinc, from 1M NaN03 aqueous solutions, with the acidic chelating extractant 3-phenyl-4-benzoylisoxazol-5-one (HPBI), in the presence of the nitrate salt of aliquat 336 (methyl-tri-n-octylammonium nitrate named TOMA.NO 3 ), has been studied in chloroform and toluene. The extracted species are TOMA.M(PBI)3 with M = Cd, zn. The synergistic extraction is described by the following equilibria: The difference observed between toluene and chloroform is mainly due to the higher distribution constant of HPBI in chloroform (logK d = 3.0) than in toluene (logK d = 2.3). The Zn extraction is more enhanced by TOMA.NO 3 than the Cd one, contrary to what is observed in the synergistic extraction using 1-phehyl-3-methyl-4-benzoylpyrazol-5-one (HPMBP).