SOLVENT EXTRACTION OF MERCURY(II) WITH SOME SULFUR-CONTAINING EXTRACTING REAGENTS

A few novel kinds of sulfur-containing extracting reagents, i.e. 2-ethyl-2-(isobutylthiomethyl)butanethiol (EIBTMBT), 3,3-diethylthietane (DETE) and 3,3-di-butylthietane (DBTE), were synthesized to investigate their extraction behaviors for mercury(II) from acidic chloride media at 303 K and compared with that of di-hexylsulfide (DHS), a conventional sulfur-containing extracting reagent. 1,2-dichloroethane was used as a diluent for all reagents. Mercury(II) was found to be extracted with DETE and DBTE according to solvation reaction mechanism as 1:2:2 metahchloride ion:reagent complexes as well as with DHS as follows: The evaluated extraction equilibrium constants for DETE and DBTE were virtually the same, i.e. K c = 2.3, regardless of the Length of the alkyl radicals and, surprisingly, less than that for DHS (K c =7.3). On the other hand, it was found to be extracted with EIBTMBT as a 1:2 metal:reagent chelate according to the following extraction reaction: