INTERFACIAL ACTIVITY AND RATE OF PALLADIUM(II) EXTRACTION WITH FLUORINATED SULFIDES

Two 2-hydroxyethylalkyl sulphides of which the alkyl chains are highly fluorinated were synthesised and their interfacial activity as well a s their ability for extracting palladium(II) were investigated. Such f luorinated compounds adsorb at the toluene/3 mol dm-3 HCl interface mo re efficiently and effectively than 2-hydroxyethyldecyl sulphide. It i s shown that an increase in the fluorinated alkyl chain length from C7 H4F10Cl to C9H4F14Cl has no important effect upon the interfacial acti vity. The fluorinated sulphides extract palladium(II) more quickly tha n their non-fluorinated analogues so that the equilibrium can be reach ed in 10 30 min. The extraction of palladium(II) is already rapid in a concentration region in which the sulphides do not exhibit a strong a dsorption at the interface. The initial extraction rates obtained with the two fluorinated sulphides considered above are comparable to thos e obtained with more surface active reagents such as 4-decylphenylamin e. Thus, the preadsorption of the fluorinated sulphides is not necessa ry for obtaining a high extraction rate.