Tétraazamacrocycles lipophiles: Extraction d'ions métalliques par une résine imprégnée

Lipophilic Tetraazamacrocyles: Extraction of Metal Ions by Impregnated Resin Extraction of Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Pb²⁺ and Ag⁺ by lipophilic tetraazamacrocycles dispersed on a solid matrix (Amberlite XAD7) is reported. Extraction efficiency is sensitive to the metal ion identity and the cavity size of the macrocycle. The influence of kinetic factors upon extraction efficiency is discussed.     

Thermodynamic studies of alkaline-earth-metal cation complexation by lipophilic dioxa,trioxa, and dithia dicarboxylic acids

Five new lipophilic dicarboxylic acids with systematic structural variation in the bridge which joins the two lipophilic carboxylic acid units have been synthesized. Potentiometric equilibrium measurements of hydrogen ion concentrations have been employed to determine the protonation constants for these lipophilic di-ionizable acyclic ligands in 90% methanol-10% water (v/v) at 25.0 °C and an ionic strength of 0.10 M and the stability constants for their complexes with Mg²⁺, Ca²⁺, and Sr²⁺. Although all five ligands exhibit the highest stability constants for Ca²⁺, the magnitude of the differences between the stability constants for complexation of Ca²⁺ versus Mg²⁺ or Sr²⁺ is found to vary widely depending upon the identity of the bridging unit which joins the two carboxylic acid end groups.     

Extraction of microamounts of calcium,strontium and barium into nitrobenzene by using hydrogen dicarbollylcobaltate in the presence of dibenzo-18-crown-6

Extraction of microamounts of calcium, strontium and barium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B⁻) in the presence of dibenzo-18-crown-6 (DB18C6, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺, ML²⁺, ML₂²⁺ and MHL₂³⁺ (M²⁺ = Ca²⁺, Sr²⁺, Ba²⁺) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.     

Extraction of85Sr by the nitrobenzene solution of bis-1,2-dicarbollylcobaltate in the presence of dibenzo-18-crown-6

Extraction of strontium by the nitrobenzene solution of bis-1,2-dicarbollylcobaltate in the presence of dibenzo-18-crown-6 (DB18C6, L) has been investigated. the equilibrium data and the typical maxima concerning the dependencies of the Sr distribution ratios on the total analytical concentration of DB18C6 in the system under study can be explained assuming that the particles Sr²⁺, SrL²⁺, SrL₂ ²⁺, SrHL³⁺ and SrHL₂ ³⁺ are extracted into the nitrobenzene phase. The values of the corresponding extraction and stability constants of the extracted species in nitrobenzene saturated with water have been determined.     

Extraction distributions of microamounts of strontium and barium in the two-phase water-HCl-nitrobenzene-dibenzo-21-crown-7-hydrogen dicarbollylcobaltate system

Extraction of microamounts of strontium and barium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B⁻) in the presence of dibenzo-21-crown-7 (DB21C7, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺, ML²⁺, ML₂²⁺ and MHL₂³⁺ (M²⁺ = Sr²⁺, Ba²⁺) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.     

Solvent extraction of microamounts of strontium and barium from water into nitrobenzene using hydrogen dicarbollylcobaltate in the presence of benzo-18-crown-6

Extraction of microamounts of strontium and barium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B⁻¹) in the presence of benzo-18-crown-6 (B18C6, L) has been investigated. The equilibrium data been explained assuming that the complexes HL⁺, ML²⁺, ML₂²⁺ and MHL₂³⁺ (M²⁺ = Sr²⁺, Ba²⁺) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.     

A quadridentate Schiff base as an extractant for thorium/IV/, uranium/VI/ and zirconium/IV/

Liquid-liquid extractions of zirconium/IV/, thorium/IV/ and uranium/VI/ with a tetradentate Schiff base, bis/salicylidene/ ethylenediamine /H₂Salen/ in benzene as the diluent have been studied. Comparison of such results with those in case of a bidentate Schiff base, N-salicylidene-p-toluidine /HSalTol/ shows that the extraction of UO ₂ ²⁺ is significantly improved if H₂Salen is used instead of HSalTol². A single extraction at pH 6.5 with H₂Salen removes uranium/VI/. Extraction of all the three metals becomes quantitative at pH 6.5. The extracted species, which have been derived from slope-analyses of extraction results, seem to be of the type [Zr₄/OH/₁₂ /HSalen/₂]Cl₂, [UO₂/OH/ /HSalen/] and [Th/OH/₃ /HSalen/].     

Substituted sulphoxide ligands in piperidinium based ionic liquid: novel solvent systems for the extraction of Pu<Superscript>4+</Superscript> and PuO<Subscript>2</Subscript><Superscript>2+</Superscript>

Sulphoxide ligands in piperidinium based ionic liquid were demonstrated as highly efficient, selective and environmentally benign systems for the extraction of plutonium from acidic aqueous solution. The extraction followed ‘cation-exchange mechanism’ via [Pu(NO₃)·L]³⁺ and [PuO₂(NO₃)·L]⁺ species. The extraction efficiency followed the trend: APSO > BPSO > BMSO. The phenyl substituted sulphoxides showed higher affinity for plutonium due to a combination of steric as well as electronic factors. Extraction process was thermodynamically spontaneous for all three solvent systems. Oxalic acid and sodium carbonate were suitable for quantitative stripping of Pu⁴⁺ and PuO₂ ²⁺, respectively. APSO in ionic liquid showed good radiolytic stability.     

Application of mercapto‐silica polymerized high internal phase emulsions for the solid‐phase extraction and preconcentration of trace lead(II)

A new class of solid‐phase extraction column prepared with grafted mercapto‐silica polymerized high internal phase emulsion particles was used for the preconcentration of trace lead. First, mercapto‐silica polymerized high internal phase emulsion particles were synthesized by using high internal phase emulsion polymerization and carefully assembled in a polyethylene syringe column. The influences of various parameters including adsorption pH value, adsorption and desorption solvents, flow rate of the adsorption and desorption procedure were optimized, respectively, and the suitable uploading sample volumes, adsorption capacity, and reusability of solid phase extraction column were also investigated. Under the optimum conditions, Pb²⁺ could be preconcentrated quantitatively over a wide pH range (2.0–5.0). In the presence of foreign ions, such as Na⁺, K⁺, Ca²⁺, Zn²⁺, Mg²⁺, Cu²⁺, Fe²⁺, Cd²⁺, Cl^? and NO₃^?, Pb²⁺ could be recovered successfully. The prepared solid‐phase extraction column performed with high stability and desirable durability, which allowed more than 100 replicate extractions without measurable changes of performance. The feasibility of the developed method was further validated by the extraction of Pb²⁺ in rice samples. At three spiked levels of 40.0, 200 and 800 μg/kg, the average recoveries for Pb²⁺ in rice samples ranged from 87.3 to 105.2%.     

Extraction of barium into nitrobenzene using hydrogen dicarbollylcobaltate in the presence of dibenzo-18-crown-6

Summary Extraction of microamounts of barium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B^-) in the presence of dibenzo-18-crown-6 (DB18C6, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺, BaL²⁺, BaL, BaHL³⁺and BaHL are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.     

Solvent extraction of microamounts of strontium and barium into nitrobenzene using hydrogen dicarbollylcobaltate in the presence of polyethylene glycol PEG 600

Extraction of microamounts of strontium and barium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B⁻) in the presence of polyethylene glycol PEG 600 (L) has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺, H₂L²⁺, ML²⁺ and MHL³⁺ (M²⁺ = Sr²⁺, Ba²⁺) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined. It was found that in water-saturated nitrobenzene the stability constant of the BaL²⁺ cationic complex species is essentially higher than that of the complex SrL²⁺.     

Efficient phase transfer of pertechnetate with bicyclic guanidinium compounds

Extraction of pertechnetate with bicyclic guanidinium compounds has been studied in the KTcO₄-buffer-H₂O/ligand-trichloromethane system. Extraction data of guanidinium ligands have been compared with trialkylmethylammonium (Aliquat 336), tetraphenylphosphonium and tetraphenylarsonium chloride. The lipophilicity of extractants investigated was determined by RP-HPLC. The efficiency of pertechnetate extraction correlates with the lipophilicity of the guanidinium compounds. 1:1 complex formation in the organic phase was observed. The influence of hydroxide, chloride and bicarbonate on the pertechnetate extraction has been investigated. Pertechnetate is extracted with great preference over OH⁻, Cl⁻ and HCO₃ ⁻, ions.     

Extraction of calcium into nitrobenzene by using hydrogen dicarbollylcobaltate in the presence of 12-crown-4

Extraction of microamounts of calcium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B^-) in the presence of 12-crown-4 (12C4,L) has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺, HL₂ ⁺, CaL²⁺ and CaL₂ ²⁺ are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.     

Extraction of microamounts of yttrium from water into nitrobenzene using hydrogen dicarbollylcobaltate in the presence of 15-crown-5

Summary Extraction of microamounts of yttrium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B^-) in the presence of 15-crown-5 (15C5,L) has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺, HL_2,⁺, YL³⁺, YL_2,³⁺and YH_-1L_2,²⁺are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.     

Extraction of Cu<Superscript>2+</Superscript>, Zn<Superscript>2+</Superscript>, and Co<Superscript>2+</Superscript> ions from aqueous solutions with calcium and magnesium phosphates

The efficiency of calcium and magnesium phosphates of different compositions in the extraction of Cu²⁺, Zn², and Co²⁺ ions from aqueous solutions was studied.     

Extraction of Ba<Superscript>2+</Superscript>, Pb<Superscript>2+</Superscript> and Cd<Superscript>2+</Superscript> into nitrobenzene by using strontium dicarbollylcobaltate in the presence of tetramethyl <Emphasis Type="Italic">p-tert</Emphasis>-butylcalix[4]arene tetraketone

From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M²⁺(aq)+SrL²⁺(nb)⇔ML²⁺(nb)+Sr²⁺(aq) taking place in the two-phase water-nitrobenzene system (M²⁺ = Ba²⁺, Pb²⁺, Cd²⁺; L = tetramethyl p-tert-butylcalix[4]arene tetraketone; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Moreover, the stability constants of the ML²⁺ complexes in water saturated nitrobenzene were calculated; they were found to increase in the order Ba²⁺<Cd²⁺<Pb²⁺.     

Membrane Transport of Pb(II) with a Cooperative Carrier Composed of Dibenzyldiaza‐18‐Crown‐6 and Palmitic Acid

A chloroform membrane system containing a given mixture of dibenzyldiaza‐18‐crown‐6 and palmetic acid was applied for transport of Pb²⁺ ions. The transport was capable of moving metal ions “uphill”. Thus, it was possible to follow the transfer of Pb(II) from the aqueous source phase to the organic layer and from the organic layer to the receiving phase. The effects of thiosulfate concentration in the receiving phase, palmetic acid and dibenzyldiaza‐18‐crown‐6 concentration in the organic phase on the efficiency of the transport system were examined. By using S₂O₃^2? ion as metal ion acceptor in the receiving phase, the amount of lead ion transport across the liquid membrane after 150 minutes is 96 ± 1.5%. The selectivity and efficiency of lead transport from aqueous solution containing Cu²⁺, Tl⁺, Ag⁺, Co²⁺, Ni²⁺, Mg²⁺, Zn²⁺, Hg²⁺, Cd²⁺, Ca²⁺ were investigated. In the presence of thiosulfate as a suitable masking agent in the source phase, the interfering effects of Ag⁺ and Cu²⁺ were diminished drastically.     

Solvent extraction of microamounts of strontium from water into nitrobenzene by using cesium dicarbollylcobaltate in the presence of 15-crown-5

Extraction distribution of microamounts of strontium in the water-CsCl-15-crown-5 (15C5,L)-nitrobenzene-cesium dicarbollylcobaltate system has been investigated. The equilibrium data have been explained assuming that the CsL⁺, CsL₂ ⁺ and SrL₂ ²⁺ complexes are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.     

Extraction of microamounts of calcium and strontium into nitrobenzene using synergistic mixture of hydrogen dicarbollylcobaltate and 2,3-naphtho-15-crown-5

Extraction of microamounts of calcium and strontium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B⁻) in the presence of 2,3-naphtho-15-crown-5 (N15C5, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺, HL₂ ⁺, CaL²⁺, CaL₂ ²⁺ and SrL₂ ²⁺ are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined. It has been found that in water saturated nitrobenzene the stability constant of the SrL₂ ²⁺ cationic complex species is substantially higher than that of the complex CaL₂ ²⁺.     

Extraction distribution of microamounts of calcium in the two-phase water-HCl-nitrobenzene-benzo-15-crown-5-hydrogen dicarbollylcobaltate system

Summary Extraction distribution of microamounts of calcium in the water-HCl-nitrobenzene-benzo-15-crown-5 (L)-hydrogen dicarbollylcobaltate (H⁺B^-) system has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺, HL, CaL²⁺and CaL are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.