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1.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+(aq)+NaL+(nb)⇔ML+(nb)+Na+(aq) taking place in the two-phase water-nitrobenzene system [M+=Li+, K+, Rb+, Cs+; L = p-tert-butylcalix[4]arene-tetrakis (N, N-dimethylthioacetamide); aq = aqueous phase, nb = nitrobenzene phase] were evaluated. Furthermore, the stability constants of the ML+ complexes in water saturated nitrobenzene were calculated; they were found to increase in the cation order Cs+<Rb+<K+<Li+<Na+.  相似文献   

2.
Extraction of microamounts of cesium by nitrobenzene solutions of sodium dicarbollylcobaltate (Na+B), potassium dicarbollylcobaltate (K+B) and rubidium dicarbollylcobaltate (Rb+B) in the presence of polypropylene glycol PPG 425 (L) has been investigated. The equilibrium data have been explained assuming that the complex species ML+ (M+ = Na+, K+, Rb+, Cs+; L = PPG 425) are present in the organic phase. The stability constants of the cationic complex species ML+ (M+ = Na+, K+, Rb+) in nitrobenzene saturated with water have been determined; they were found to increase in the series of Rb+ < K+ < Na+.  相似文献   

3.
Extraction of microamounts of cesium by nitrobenzene solutions of sodium dicarbollylcobaltate (Na+B?), potassium dicarbollylcobaltate (K+B?) and rubidium dicarbollylcobaltate (Rb+B?) in the presence of polypropylene glycol PPG 425 (L) has been investigated. The equilibrium data have been explained assuming that the complex species ML+ (M+ = Na+, K+, Rb+, Cs+; L = PPG 425) are present in the organic phase. The stability constants of the cationic complex species ML+ (M+ = Na+, K+, Rb+) in nitrobenzene saturated with water have been determined; they were found to increase in the series of Rb+ < K+ < Na+.  相似文献   

4.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+(aq)+NaL+(nb)⇄ML+(nb)+Na+(aq) taking place in the two-phase water-nitrobenzene system (M+=Li+, K+, Rb+, Cs+; L=dibenzo-24-crown-8; aq=aqueous phase, nb=nitrobenzene phase) were evaluated. Further, the stability constants of the ML+ complexes in nitrobenzene saturated with water were calculated; they were found to increase in the Cs+Rb+L+Na+ order.  相似文献   

5.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+(aq)+CsL+(nb)⇔ML+(nb)+Cs+(aq) taking place in the two-phase water-nitrobenzene system (M+ = Li+, Na+, K+, Rb+; L = hexaethyl p-tert-butylcalix[6]arene hexaacetate; aq = aqueous phase, nb = nitrobenzene phase) were determined. Moreover, the stability constants of the ML+ complexes in water saturated nitrobenzene were calculated; they were found to increase in the cation order Rb+<Cs+<K+<Na+<Li+.  相似文献   

6.
Extraction of microamounts of cesium by nitrobenzene solutions of potassium dicarbollylcobaltate (K+B) and rubidium dicarbollylcobaltate (Rb+B) in the presence of benzo-15-crown-5 (B15C5, L) has been investigated. The equilibrium data have been explained assuming that the complexes ML+ and ML2+ (M+ = K+, Rb+, Cs+) are present in the organic phase. The stability constants of the species ML+ and ML2+ (M+ = K+, Rb+) in nitrobenzene saturated with water have been determined.  相似文献   

7.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+(aq)+NaL+(nb)⇄ML+(nb)+Na+(aq) taking place in the two-phase water-nitrobenzene system (M+=Li+, K+, Rb+, Cs+; L=18-crown-6; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. The stability constants of the ML+ complexes in nitrobenzene saturated with water were calculated; they are found to increase in the cation order Cs+Li+Na+Rb+K+. Further, the individual extraction constants for the NaL+, KL+, RbL+ and CsL+ complex species in the wate-nitrobenzene system were determined; their values increase in the series Na+Rb+Cs+K+.  相似文献   

8.
Summary From extraction experiments and g-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+(aq) + CsL+(nb) ? ML+(nb) + Cs+(aq) taking place in the two-phase water-nitrobenzene system (M+ = NH, K+, Rb+, Tl+; L = dibenzo-21-crown-7; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Further, the stability constants of the ML+ complexes in water saturated nitrobenzene were calculated; they were found to increase in the order Cs+<K+ = Rb+?NH<Tl+.  相似文献   

9.
From extraction experiments and γ-activity measurements, the extraction constants corresponding to the general equilibrium M+(aq) + 1·Cs+(nb) \rightleftarrows \rightleftarrows 1·M+(nb) + Cs+(aq) taking part in the two-phase water–nitrobenzene system (1 = hexaarylbenzene-based receptor; M+ = H3O+, NH4 +, Ag+, K+, Rb+, Tl+; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Furthermore, the stability constants of the ML+ complex species in nitrobenzene saturated with water were calculated; they were found to increase in the series of Rb+ < K+ < Ag+, Tl+ < H3O+, NH4 +.  相似文献   

10.
Extraction of microamounts of cesium by nitrobenzene solutions of sodium, ammonium and thallium dicarbollylcobaltates (M+B; M+ = Na+, NH4+, Tl+) in the presence of benzo-15-crown-5 (B15C5, L) has been investigated. The equilibrium data have been explained assuming that the complexes ML+ and ML2+ (M+ = Na+, NH4+, Tl+; L = B15C5) are present in the organic phase. The stability constants of the complex species ML+ and ML2+ in nitrobenzene saturated with water have been determined.  相似文献   

11.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+(aq) + 1·Cs+(nb) ? M+(nb) + Cs+(aq) taking place in the two-phase water–nitrobenzene system (M+ = Li+, Na+, H+, NH4 +, Ag+, K+, Rb+, Tl+; 1 = dibenzo-30-crown-10; aq = aqueous phase, nb = nitrobenzene phase) were determined. Furthermore, the stability constants of the 1·M+ complexes in water-saturated nitrobenzene were calculated; they were found to increase in the series of Cs+ < H+, Ag+ < NH4 + < Na+ < Rb+ < Li+ < K+, Tl+.  相似文献   

12.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+ (aq) + 1·Na+ (nb) ⇔ 1·M+ (nb) + Na+ (aq) taking place in the two-phase water–nitrobenzene system (M+ = Li+, H3O+, NH4 + {\rm NH}_{4}^{ + } , Ag+, K+, Rb+, Tl+, Cs+; 1 = barium ionophore I; aq = aqueous phase, nb = nitrobenzene phase) were determined. Furthermore, the stability constants of the 1·M+ complexes in water-saturated nitrobenzene were calculated; they were found to increase in the series of Cs+ < Rb+ < NH4 + {\rm NH}_{4}^{ + } , K+ < H3O+ < Na+ < Ag+, Tl+ < Li+.  相似文献   

13.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+(aq)?+?1·Cs+(nb) ? 1·M+(nb)?+?Cs+(aq) taking place in the two-phase water–nitrobenzene system (M+?=?Li+, Na+, K+, Rb+, H3O+, NH4 +, Tl+; 1?=?beauvericin; aq?=?aqueous phase, nb?=?nitrobenzene phase) were determined. Moreover, the stability constants of the 1·M+ complexes in water-saturated nitrobenzene were calculated; they were found to increase in the series of Rb+?<?Na+, H3O+?<?Tl+?<?NH 4 +? <?K+?<?Li+.  相似文献   

14.
Formation constants (K ML) of 1:1 complexes of 15-(2,5-dioxahexyl)-15-methyl-16-crown-5 (L16C5) and 15,15-dimethyl-16-crown-5 (DM16C5) with alkali metal ions were determined in acetonitrile (AN) and propylene carbonate (PC) by conductometry at 25°C. Except for the case of Li+-and K+-16C5 complexes in PC, the selectivity sequences of L16C5 and DM16C5 are identical with those of the parent crown ether 16-crown-5 (16C5) regardless of the solvent (AN, PC, methanol) (Na1 > Li+ > K+ > Rb+ > Cs+), which show the size-fit correlation. The selectivities of L16C5 and DM16C5 for the alkali metal ions are governed not by the sidearms but by the cavity size. The stability of the crown ether complex is dependent not on the dielectric constant but largely on the donor number of the solvent. TheK ML(M1 +)/K ML(M2 +) ratio of L16C5 or 16C5 varies very much with the solvent in the cases of M1=Na, M2=K and M1=Na, M2=Li, but that of DM16C5 is almost constant regardless of the solvent.  相似文献   

15.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+ (aq) + CsL+ (nb) ? ML+ (nb) + Cs+ (aq) taking place in the two–phase water–nitrobenzene system (M+ = K+, Rb+, $ {\text{NH}}_{4}^{ + } $ , Ag+, Tl+; L = calix[4]arene-bis(t-octylbenzo-18-crown-6); aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Furthermore, the stability constants of the ML+ complexes in nitrobenzene saturated with water were calculated; they were found to increase in the following cation order: $ {\text{NH}}_{4}^{ + } $  < K+ < Ag+ < Rb+ < Tl+.  相似文献   

16.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+(aq) + Cs+(org) ⟺ M+(org) + Cs+(aq) taking place in the two-phase water–phenyltrifluoromethyl sulfone (abbrev. FS 13) system (M+ = Li+, H3O+, Na+, NH4+ \hbox{NH}_{4}{}^{+} , Ag+, Tl+, K+, Rb+; aq = aqueous phase, org = FS 13 phase) were evaluated. Furthermore, the individual extraction constants of the M+ cations in the mentioned two-phase system were calculated; they were found to increase in the series of Li+ < H3O+ < Na+< NH4 + \hbox{NH}_{4}{}^{ + } < Ag+ < Tl+ < K+ < Rb+ < Cs+.  相似文献   

17.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the equilibrium M +(aq) + 1 · Na+ (nb) ⇄ 1 · M + (nb) + Na+ (aq) taking place in the two-phase water-nitrobenzene system (M + = Li+, H3O+, NH4 +, Ag+, K+, Rb+, Tl+, Cs+; 1 = tetraphenyl p-tert-butylcalix[4]arene tetraketone; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Moreover, the stability constants of the 1 · M + complexes in water saturated nitrobenzene were calculated; they were found to increase in the order Cs+ < Rb+ < Tl+ < K+ < NH4 + < Ag+ < H3O+ < Li+. Correspondence: Emanuel Makrlík, Faculty of Applied Sciences, University of West Bohemia, Pilsen, Czech Republic.  相似文献   

18.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+ (aq) + Cs+ (nb) ? M+ (nb) + Cs+ (aq) taking place in the two-phase water–nitrobenzene system (M+ = Ag+, K+, Rb+, Tl+; 1 = 1,3-alternate-25,27-bis(1-octyloxy)calix[4]arene-crown-6; aq is aqueous phase, nb is nitrobenzene phase) were determined. Moreover, the stability constants of the M+ complexes in water-saturated nitrobenzene were calculated; they were found to increase in the series of K+ < Rb+ < Ag+ < Tl+.  相似文献   

19.
Stability constants K ML for the 1:1 complexes of Na+, K+, Rb+, and Cs+ with dibenzo-24-crown-8 (DB24C8) and dibenzo-18-crown-6 (DB18C6) in water have been determined by a capillary electrophoretic technique at 25°C. The K ML sequence is Na+ < K+ < Rb+ < Cs+ for DB24C8 and Na+ < K+ > Rb+ > Cs+ for DB18C6. Compared with DB18C6, DB24C8 exhibits higher selectivity for K+ over Na+, but lower selectivity for K+, Rb+, and Cs+. To evaluate the solvation of the complexes in water, their transfer activity coefficients sH2O between polar nonaqueous solvents and water have been calculated. The sH2O values provide the following information: interactions with water of the metal ions and of the crown-ether oxygens are greatly reduced upon complexation and the complexes undergo hydrophobic hydration in water; the character of each alkali metal ion in solvation is more effectively masked by DB24C8 than by DB18C6, because of the larger and more flexible ring structure of DB24C8. Solvent effects on the complex stabilities are discussed on the basis of the sH2O values.  相似文献   

20.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+(aq)+NaL+(nb)⇔ML+(nb)+Na+(aq) taking place in the two-phase water-nitrobenzene system (M+ = Li+, H3O+, NH4+, Ag+; L = hexaethyl calix[6]arene hexaacetate; aq = aqueous phase, nb = nitrobenzene phase) were determined. Furthermore, the stability constants of the ML+ complexes in water saturated nitrobenzene were calculated; they were found to increase in the cation order H3O+<NH4+<Li+<Ag+.  相似文献   

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