Solvent extraction of microamounts of yttrium from water into nitrobenzene by using hydrogen dicarbollylcobaltate in the presence of benzo-15-crown-5

Summary Extraction of microamounts of yttrium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B^-) in the presence of benzo-15-crown-5 (B15C5,L) has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺, HL, YL³⁺, YL and YH_-1L 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.     

The extraction behavior of some dicarbollylcobaltate crown extraction systems

The extraction of cesium, strontium and barium by a nitrobenzene solution of dicarbollylcobaltate in the presence of various crown ethers has been investigated and the influence of the substituent of crown to the extraction possibility has been observed. It has been found, that the addition of DB15C5, DB18C6 and DB21C7 (but not DB24C8 and DCH24C8) increases the distribution ratio of Cs by one order of magnitude. The fivemembered crowns are usually more efficient extractants for strontium than DCH18C6, which is widely used for strontium separation. The distribution ratio of strontium D_Sr decreases in the order 15-crown-5>benzo-15-crown-5>2-hydroxymethyl-15-crown-5>cyclohexyl-15-crown-5 >dibenzo-15-crown-5> nitrobenzo-15-crown-5. The selectivity α(Sr/Ca) decreases in the order 15C5>B15C5>DB15C5>2HM15C5>CH15C5. A selectivity factor α(Sr/Ca)≥1000 can be reached in the presence of 15C5 and B15C5. Six-membered and four-membered crowns extract strontium worse than most of the five-membered crowns. The selectivity factors α(Sr/Ca)≈100 have been reached for six-membered crowns and α(Sr/Ca)<1 has been found for 12C4. The extraction of barium by a nitrobenzene solution of dicarbollylcobaltate in the presence of 15C5 is even more efficient as the extraction of strontium. In that system D_Sr>10⁴ and D_Ba>10⁴ have been found for the extraction of Sr and Ba by a 0.01M nitrobenzene solution of dicarbollylcobaltate (c_B=0.01 mol/l) from 0.1M HNO₃. Maximal values of separation factor α(Ba/Sr) have been found in the system containing DB21C7.     

Extraction distribution of microamounts of strontium in the two-phase water-KCl-15-crown-5-nitrobenzene-potassium dicarbollylcobaltate system

Summary Extraction of microamounts of strontium by a nitrobenzene solution of potassium dicarbollylcobaltate (K⁺B^-) in the presence of 15-crown-5 (15C5, L) has been investigated. The equilibrium data have been explained assuming that the complexes KL⁺, KL and SrL 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⁺.     

Synergistic extraction of Ce(III), Eu(III) and Tm(III) with a mixture of picrolonic acid and benzo-15-crown-5 in chloroform

Summary The synergistic mixture comprising picrolonic acid (HPA) and benzo-15-crown-5 (B15C5) in chloroform has been used for the extraction of Ce(III), Eu(III) and Tm(III) as representatives of lanthanide(III) ions from pH 1-2 solutions having ionic strength of 0.1 mol^. dm^-3(K⁺/H⁺, Cl^-). The composition of the extracted species has been determined as M(PA)₃^. nB15C5 where M is Ce, Eu and Tm and n=1 or 2. The influence of various anions and cations on the extraction of these ions has also been studied and only oxalate, cyanide and tartrate have some deleterious effect. The extraction equilibrium constants have been evaluated and discussed.     

Extraction of microamounts of strontium into nitrobenzene by using hydrogen dicarbollylcobaltate in the presence of dicyclohexyl-18-crown-6

Summary Extraction of microamounts of strontium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B^-) in the presence of dicyclohexyl-18-crown-6 (DCH18C6, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺, HL, SrL²⁺and SrL 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 cesium by the nitrobenzene solution of hydrogen bis-1,2-dicarbollylcobaltate in the presence of 15-crown-5

Extraction of microamounts of cesium by the nitrobenzene solution of H⁺ bis-1,2-dicarbollylcobaltate (H⁺B⁻) in the presence of 15-crown-5 (15C5, L) has been investigated. The equilibrium data have been explained assuming the complexes HL⁺, HL₂ ⁺, CsL⁺ and CsL₂ ⁺ to be 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.     

Extraction distribution of microamounts of barium in the two-phase water-HNO3-15-crown-5-nitrobenzene-hydrogen dicarbollylcobaltate system

Summary Extraction of microamounts of barium 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 and BaL are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.     

Determination of microamounts strontium by substoichiometric isotope dilution analysis

The isotope dilution with substoichiometric separation for the determination of strontium has been investigated. Strontium can be extracted with a substoichiometric amount of bis-1,2-dicarbollylcobaltate in nitrobenzene in the presence of 15-crown-5. It has been found, that Li⁺, Mg²⁺, Ca²⁺ and Fe³⁺ do not interfere in the strontium determination but the high extraction of K⁺, Na⁺ and NH₄ ⁺ ions results in marked influence.     

Solvent extraction of strontium into nitrobenzene using hydrogen dicarbollylcobaltate in the presence of 12-crown-4

Extraction of microamounts of strontium 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 ⁺, SrL²⁺ 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.     

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.     

Mathematical modeling of separation of microamounts of strontium from yttrium in the two-phase water-nitrobenzene extraction system

A rapid extraction separation of microamounts of Sr²⁺ from Y³⁺ using HCl, benzo-15-crown-5 (B15C5) and hydrogen dicarbollylcobaltate (H⁺B^-) in the two-phase water-nitrobenzene system was developed. The reached separation factor α(Sr/Y) was higher than 10⁵.     

Investigation on the extraction of strontium ions from aqueous phase using crown ether-ionic liquid systems

The extraction of strontium ions using DCH18C6 as the extractant and various ionic liquids (ILs) as solvents has been investigated. The distribution ratio of Sr²⁺ can reach as high as 10³ under certain conditions, much larger than that in DCH18C6/n-octanol system. The extraction capacity depends greatly on the structure of ionic liquids. In IIs-based extraction systems, the extraction efficiency of strontium ions is reduced by increasing the concentration of nitric acid and can also be influenced directly by the presence of Na⁺ and K⁺ in the aqueous phase. It is confirmed that the extraction proceeds mainly via a cation-exchange mechanism.     

Extraction of Alkali Metal (Li, Na, K) Picrates with Benzo-15-crown-5 into Various Organic Solvents. Elucidation of Fundamental Equilibria Determining the Extraction-ability and -selectivity

To quantitatively elucidate the effects of the benzo group on the extraction-selectively and -ability of benzo-15-crown-5 (B15C5)for alkali metal ions, the constants of the overall extraction (K_ex), thedistribution for various diluents having low dielectric constants (K_D,MLA), and the aqueousion-pair formation (K_MLA) of B15C5-alkali metal (Li, Na, K) picrate 1:1:1 complexes (MLA) weredetermined at 25 °C. The partition constants of B15C5were also measured at 25 °C. The log K_MLA values for Li⁺, Na⁺, and K⁺ are -0.32 ± 0.22, 2.66 ± 0.19, and 0.71 ± 0.47, respectively. In going from 15-crown-5 (15C5) to B15C5, the benzo group considerably decreasesthe K_MLA value for the same alkali metal ion. The distributionbehavior of B15C5 and its 1:1:1 complexes with the alkali metal picrates closely obeys regularsolution theory, omitting chloroform. Molar volumes and solubility parameters of B15C5and the 1:1:1 complexes were determined. For every diluent, the K_ex valuefor B15C5 increases in the order Li⁺ < K⁺ < Na⁺. K_D,MLA makes anunfavorable contribution to the Na⁺ extraction-selectivity of B15C5 because of the smallest molar volume of the Na(B15C5)A complex. The Na⁺ extraction-selectivity of B15C5 is determined completely by much the highest K_Na(B15C5)A value.The extraction-ability and -selectivity of B15C5 for the alkali metal picrates are compared with those of 15C5on the basis of the underlying equilibrium constants.     

Selective separation of yttrium(III) through a liquid membrane system using 2-thenoyltrifluoroacetone as an extractant carrier

2-Thenoyltrifluoroacetone has been offered as a mobile carrier in organic phase for the transport and selective separation of yttrium from aqueous media using a liquid membrane system. Perceivably, the use of n-propylamine (PA) in the source phase enhances the transport of yttrium ions. The extraction and stripping conditions have entirely been evaluated and explained. The suggested method has been utilized for the separation of yttrium(III) from its binary mixtures with strontium(II) and some other cations such as Ni²⁺, Co²⁺, Ag⁺, Fe²⁺, Al³⁺, Cu²⁺, Hg²⁺and Cs⁺ in aqueous solutions of pH 5.4 in the presence of PA, while 1 M nitric acid was acting as a stripping agent in the receiving division. Cyanide ion and 5-sulfosalicylic acid have been used as masking agents to minimize the interferences from different transition metal ions and Al³⁺ in the source phase, respectively. ⁹⁰Y in secular equilibrium with ⁹⁰Sr in the source phase, was transferred to receiving phase and separated completely from its long-lived parent isotope. The activity of the transported ⁹⁰Y was found to decay with a half-life 64.17 ± 0.05 h. The purity of yttrium-90 was comparable or better than the other applied liquid membrane systems for purification of yttrium-90.     

Coprecipitation of 15-crown-5 ether complexes of lead and strontium with tungstosilicic acid

Lead as well as strontium form low solubility compounds of composition (ML₂)₂A·nH₂O, (M=Pb²⁺, Sr²⁺), in the presence of 15-crown-5 (L) and tungstosilicic acid (H₄A) in acid media as found by radiometric precipitation titration. “Sandwich” structure of crown-ether complexes of lead and strontium could be expected due to the small size of cavity of 15-crown-5. Coprecipitation of PbL_2/su2+ with crown complexes of strontium cation after adding tungstosilicic acid was studied in 0.01 mol·dm⁻³ HNO₃. A significant influence of H⁺ cation in 1 mol·dm⁻³ HNO₃ on coprecipitation of lead was observed. Formation of HL⁺ complexes by protonisation of 15-crown-5 competes to the formation of ML₂ ²⁺ complexes (approximately twenty percent of 15-crown-5 are used for creation of HL⁺ complexes). Formation of low solubility salts was utilised for separation of lead from strontium in 0.01 mol·dm⁻³ HNO₃. The ratio of constant stability of lead and strontium β‘ with 15-crown-5 in 0.01 mol·dm⁻³ HNO₃ was calculated. The separation factor S(Pb/Sr) depends on the ratio of stability constants β_PbL2/β_SrL2 The precipitation method can be used for separation of metals with high constant stability with crown ethers from solutions containing other metals in the case of gradual addition of crown.     

Extraction of microamounts of strontium from water into 1-trifluoromethyl-3-nitrobenzene using hydrogen heptachlorodicarbollylcobaltate in the presence of PEG 400

Summary Extraction of microamounts of strontium by a 1-trifluoromethyl-3-nitrobenzene solution of hydrogen heptachlorodicarbollylcobaltate (H⁺B^-) in the presence of polyethylene glycol ligand PEG 400 (L) has been investigated. The equilibrium data have been explained assuming that the HL⁺and SrL²⁺complexes are extracted into the organic phase. The values of extraction and stability constants of the complex species in 1-trifluoromethyl-3-nitrobenzene saturated with water have been determined.     

Complex Formation of Crown Ethers and Cations in Water–Organic Solvent Mixtures: Part XI. Effects of the Preferential Solvation of Benzo-15-Crown-5 and Acid-Base Properties of the Mixtures on the Thermodynamic Functions for Complex Formation of Benzo-15-Crown-5 with Na+ in Propan-1-ol–Water Mixtures at 298.15 K

The thermodynamic functions of complex formation of benzo-15-crown-5 ether (B15C5) and sodium cation (Na⁺) in the mixtures of propan-1-ol (PrOH) with water at 298.15 K have been calculated from experimental measurements. The equilibrium constants of B15C5/Na⁺ complex formation have been determined by conductivity measurements. The enthalpic effect of complex formation has been measured by a calorimetric method. The complexes are enthalpy stabilized but entropy destabilized in the PrOH–H₂O mixtures. The effects of preferential solvation of B15C5 by molecules of the organic solvent, solvation of the sodium cation, as well as the acid-base properties of propan-1-ol–water mixtures on the complex formation processes are discussed.