R. A. Khisamutdinov

Fatty Imidazolines: A Novel Extractant for the Recovery of Palladium(II) from Hydrochloric Acid Solutions

The extraction of palladium(II) from hydrochloric acid solutions with a novel highly basic extractant, a mixture of homologous 1-[2-(alkanoylamino)ethyl]-2-alkyl-2-imidazolines (AAI) in toluene with 15% (v/v) of n-octanol was studied. Palladium(II) is rapidly and most effectively extracted with AAI hydrochloride at the low hydrochloric acid (chloride ions) concentration (up to 1 M) and can be completely separated from Fe(III), Cu(II), and Co(II). The palladium(II) extraction at the optimum acidity occurs via an anion-exchange mechanism with the formation of ionic associates (LH)2PdCl4 (K ex = (1.5 ± 0.2) · 104 at 0.5 M HCl) and is accompanied by the dimerization of palladium(II) in the organic phase with the formation of ionic associates (LH)2Pd2Cl6 (K dim = (3.9 ± 0.4) · 10−4 at 0.5 M HCl). The anion-exchange extraction of palladium(II) at the acidity of 0.5 M HCl is temperature independent in the range 20–49°C. Complete stripping of palladium(II) can be performed using a 5% solution of thiourea in 0.1 M HCl.

Extraction of hydrochloric and nitric acid with 1-{[2-(2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]-methyl)-1H-1,2,4-triazole and (RS)-1-(4-Chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-yl-methyl)-pentan-3-ol

Extraction of hydrochloric and nitric acid with 1-{[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]-methyl}-1H-1,2,4-triazole (propiconazole) and hydrochloric acid with (RS)-1-(4-chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-yl-methyl)-pentan-3-ol (tebuconazole) was studied. It is established that extraction of acids proceeds with the formation of monosolvates as an exothermic process. Effective extraction constants of acids are evaluated. By means of the IR and 1H NMR spectroscopy it was shown that the protonaccepting center of tebuconazole is N4 atom of the triazole ring.

Extraction of palladium(II) from hydrochloric acid solutions with triacylated ethyleneamines

Extraction of palladium(II) from hydrochloric acid solutions with novel efficient extractants, triacylated ethyleneamines, was studied. The most effective extraction of palladium(II) was observed from 0.5–1 M HCl solutions. Extraction of palladium(II) from 1 M HCl solutions was found to occur through mixed (coordination and anion-exchange) mechanism. In the field of dominance of the anion-exchange mechanism of the extraction of palladium(II) with triacylated pentaethylenehexamine the concentration constant of palladium(II) extraction was calculated, and thermodynamic parameters of extraction were evaluated.

Propiconazole and Penconazole as Effective Extractants for Selective recovery and concentration of platinum(IV) and palladium(II) from hydrochloric acid solutions formed in leaching of spent aluminoplatinum and aluminopalladium catalysts

Selective recovery and concentration of platinum(IV) and palladium(II) from hydrochloric acid solutions of varied composition was studied using commercial reagents propiconazole and penconazole as extractants. The ranges of hydrochloric acid concentrations for effective extraction and highly selective separation of platinum metals from Al(III) and Ni(II) with propiconazole (toluene with 15 vol % n-decanol as deluent) and penconazole (chloroform) were determined. The conditions for 10-fold selective concentration of platinum metals with recovery of more than 99.9% of metal ions into the organic phase were found. The conditions for quantitative (>99%) stripping of platinum(IV) with a hydrochloric acid solution of thiourea and palladium(II) with ammonia solution were determined. The results obtained can be used for optimizing the modes of selective recovery of platinum(IV) and palladium(II) from hydrochloric acid solutions formed in leaching of alumina-supported platinum-rhenium, platinum-nickel, and palladium catalysts.

Extraction of gold(III), palladium(II), and platinum(IV) by 1-[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-ylmethyl]-1H-1,2,4-triazole from hydrochloric acid solutions

The extraction of gold(III), palladium(II), and platinum(IV) with 1-[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl]-1H-1,2,4-triazole from hydrochloric acid solutions into toluene has been studied. The extraction follows the anion-exchange mechanism. The concentration constants and thermodynamic parameters of the extraction reaction have been calculated. The reagent is proposed for use in the extraction of the sum of precious metals.

Extraction of palladium(II) with (RS)-1-(4-chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl)pentan-3-ol from nitric acid solutions

Extraction of palladium(II) with (RS)-1-(4-chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl)pentan-3-ol from nitric acid solutions (carbon tetrachloride as diluent, octanol as modifier) was studied. Optimal extraction conditions were found. The reagent was shown to extract efficiently metal ions in a wide range of aqueous phase acidity by coordination mechanism. Aqueous ammonia solution was proposed as stripping agent for palladium(II). Concentrational extraction constants were calculated and thermodynamic parameters of extraction were determined.

Extraction of gold(III) with (RS)-1-(4-chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-yl-methyl)-pentan-3-ol from hydrochloric acid solutions

Extraction of gold(III) with (RS)-1-(4-chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl)-pentan-3-ol from 3 M hydrochloric acid solutions (with chloroform as a diluent) has been studied. Optimal extraction conditions have been found. The reagent has been shown to extract efficiently metal ion from solutions containing 3 M hydrochloric acid due to formation of coordination bond between gold(III) and the N4 atom of the triazole ring. The coordination mechanism of gold(III) extraction has been proposed on the basis of the data obtained. Concentration constants of extraction have been calculated, and the thermodynamic parameters of extraction have been determined.

Extraction of palladium(II) from hydrochloric acid solutions by (RS)-1-(4-chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl)-pentan-3-ol

The extraction properties of (RS)-1-(4-chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl)-pentan-3-ol (with chloroform as a diluent) with respect to palladium(II) were studied. Palladium(II) was found to be efficiently extracted by the reagent from 0.1–6 M HCl solutions by the coordination mechanism. The rate of palladium(II) recovery depends on the hydrochloric acid and chloride ion concentrations in the aqueous phase. Conditions for the selective separation of palladium(II) and copper(II) from nickel(II), cobalt(II), and iron(III) were determined.

Extraction of rhodium(III) from hydrochloric acid solutions with bis-acylated triethylenetetramine dihydrochloride

Extraction of rhodium(III) from hydrochloric acid solutions with bisacylated triethylenetetramine dihydrochloride has been studied. The optimal extraction conditions have been elaborated. At the phase contact time of 5 min rhodium(III) is extracted via the interphase anionic exchange mechanism. Concentration constants of extraction have been calculated, and thermodynamic parameters of extraction have been estimated. The extracted ion associate has been isolated and characterized by means of electronic, IR, and 13C NMR spectroscopy.

Gold(III) and palladium(II) extraction from hydrochloric acid solutions with (RS)-1-[2-(2,4-dichlorophenyl)pentyl]-1H-1,2,4-triazole

Gold(III) and palladium(II) extraction from 3 mol/L hydrochloric acid solutions with (RS)-1-[2-(2,4-dichlorophenyl)pentyl]-1H-1,2,4-triazole (chloroform diluent) was studied. Optimal extraction conditions were found. Coordination mechanism of extraction was established on the basis of IR and NMR spectra of extracted compounds. Concentrational extraction constants were calculated and thermodynamic parameters of the process were assessed.