Abstract
Spectrophotometric methods were used to study the reaction of complexation of tungsten with derivatives of o-hydroxythiophenol (HTPDs) {2-hydroxy-5-chlorothiophenol (HCTP), 2-hydroxy-5- bromothiophenol (HBTP) and 2-hydroxy-5-iodothiophenol (HITP )} in the presence of aminophenols. Aminophenols used were 2(N,N-dimethylaminomethyl)-4-chlorophenol (AP1) and 2(N,N- dimethylaminomethyl)-4-bromophenol (AP2), 2(N,N-dimethylaminomethyl) -4-iodophenol (AP3).Optimal conditions for the formation and extraction of mixed ligand complexes (MLC) were found, and the ratios of the components in the complexes established. It revealed that MLC are formed in a weakly acidic environment (рНopt 4.5-5.5). The maximum in the light absorption spectrum is observed at λ=460-490 nm. The molar coefficient of light absorption is equal to ε = (2.0-2.8) × 104. Optimal conditions for the formation and extraction of these compounds is the concentration of (1.2-2.5) × 10-3 mol / l GTP and (2.0-2.8)×10-3 mol/l AP. The maximum optical density is reached within 5-8 minutes. Tungsten MLC extracts with HTP and AP obeys Beer's law at concentrations of 0.04–3.8 μg/5 ml. The proposed method was applied to determine Tungsten in steel and in soils.