THE INTERACTIONS OF METAL EXTRACTANT REAGENTS .6. AGGREGATION EQUILIBRIA OF CYANEX-302 AND SPAN-80 IN TOLUENE SOLUTIONS

The aggregation equilibria of the commercial extractant Cyanex 302 in toluene have been studied by vapor pressure osmometry (VPO) at differe nt temperatures. The experimental data, treated both graphically and n umerically by means of the CPMIN program, can be explained by assuming the formation of a dimer species of the active component bis(2,4,4-tr imethylpentyl)thiophosphinic acid for which the aggregation constants have been determined at 28, 40 and 50-degrees-C. The influence of othe r components of the commercial reagent in the aggregation equilibria h ave also been considered. The interaction between Cyanex 302 and the n on-ionic surfactant Span 80 in toluene has also been investigated by V PO and the experimental results interpreted by the formation of mixed species between both reagents.