STUDY OF THE ANTAGONISTIC EXTRACTION OF PALLADIUM(II) WITH 1-PHENYL-3-METHYL-4-PROPIONYLPYRAZOLONE-5-ONE AND AN ORGANIC AMINE

Abstract

The extraction mechanism of palladium (II) with the acidic chelating extractant 1-phenyl-3-methyl-4-propionylpyrazolone-5-one (HPMPP) and the tertiary amine (R₁R₂R₃N) has been studied by spectrophotometry. A noticeable antagonistic extraction effect was observed in the extraction system under the given conditions. To understand this phenomenon, a preliminary work was performed to explain the mechanism of this reaction. According to the theory of the corresponding solutions (TCS), the association reaction between HPHBP and R₁R₂R₃N was represented and discussed in the organic phase. An associated species HPMPP · NR₁R₂R₃ formed through hydrogen bonding in chloroform medium might be the main reason why an antagonistic extraction effect occurs. The association constant between HPMPP and R₁R₂R₃N was calculated to be 2.2 ± 0.1.

ACKNOWLEDGMENT

This work has financially supported by Shaanxi Province Natural Science Foundation of China.

The author wishes to thank Dr. G. Uchiyama, head of Process Safety Laboratory, Department of Fuel Cycle Safety Research, Japan Atomic Energy Research Institute, Dr. T. Tanaka, Mr. T. Maeda, M. Goto and Mr. Y. Onuma for their assistance in writing.