Extraction of Platinum(IV) with Nonylthiourea Dissolved in Chloroform from Hydrochloric Acid Media

Abstract

The extractant nonylthiourea (NTH) in chloroform has been investigated for the extraction of Pt(IV) from chloride solutions at ionic strength of I = 4.0 M and at 22°C. It has been found that chloride concentration has a negative effect on the extraction equilibrium, while proton concentration has no effect. The numerical analysis of the equilibrium data has shown that the extraction of PtCl ₆ ²⁻ with NTH can be interpreted by the formation of PtCl₄(NTH) and PtCl₄(NTH)₄ species with their respective equilibrium constants of log K ₁₁ = 5.06 ± 0.01 and log K ₁₄ = 14.12 ± 0.04 in 4 M HCl. FTIR spectra of the free NTH and the NTH–Pt(IV) complex were studied to obtain some information on the interaction between Pt(IV) ions and NTH molecules.