Solvent extraction of alkali metals by crown ethers

Competitive Extraction of Pb2+ by Dicyclohexano-18-crown-6 from Heavy Metal Aqueous Solutions

“…When equilibrium is achieved between an aqueous phase containing a metal ion M m+ and a counteranion Aand an organic phase containing a neutral crown ether L, a crown ether complex ML n A m is considered to be formed (Frensdorff, 1971;Tanigawa et al, 1988) and the overall equilibrium can be expressed by means of the overall equilibrium constant K:…”

“…The very low distribution ratios obtained for Cu 2+ , Co 2+ , and Zn 2+ with benzo-15-crown-5 are not explained by the fit between the carrier cavity and the size of metal ion: other factors, like the substitution groups and the number of oxygen atoms in the crown ether molecule, and also possible changes in the conformation of the macrocycle during complexing, have an important influence on extraction (Izatt et al, 1983(Izatt et al, , 1988Morosanova et al, 1984;Tanigawa et al, 1988).…”

Competitive Extraction of Pb2+ by Dicyclohexano-18-crown-6 from Heavy Metal Aqueous Solutions

“…When equilibrium is achieved between an aqueous phase containing a metal ion M m+ and a counteranion Aand an organic phase containing a neutral crown ether L, a crown ether complex ML n A m is considered to be formed (Frensdorff, 1971;Tanigawa et al, 1988) and the overall equilibrium can be expressed by means of the overall equilibrium constant K:…”

“…The very low distribution ratios obtained for Cu 2+ , Co 2+ , and Zn 2+ with benzo-15-crown-5 are not explained by the fit between the carrier cavity and the size of metal ion: other factors, like the substitution groups and the number of oxygen atoms in the crown ether molecule, and also possible changes in the conformation of the macrocycle during complexing, have an important influence on extraction (Izatt et al, 1983(Izatt et al, , 1988Morosanova et al, 1984;Tanigawa et al, 1988).…”

Competitive Extraction of Pb2+ by Dicyclohexano-18-crown-6 from Heavy Metal Aqueous Solutions

“…When equilibrium is achieved between an aqueous phase containing a metal ion M m+ and a counteranion Aand an organic phase containing a neutral crown ether L, a crown ether complex ML n A m is considered to be formed (Frensdorff, 1971;Tanigawa et al, 1988) and the overall equilibrium can be expressed by means of the overall equilibrium constant K:…”

“…The very low distribution ratios obtained for Cu 2+ , Co 2+ , and Zn 2+ with benzo-15-crown-5 are not explained by the fit between the carrier cavity and the size of metal ion: other factors, like the substitution groups and the number of oxygen atoms in the crown ether molecule, and also possible changes in the conformation of the macrocycle during complexing, have an important influence on extraction (Izatt et al, 1983(Izatt et al, , 1988Morosanova et al, 1984;Tanigawa et al, 1988).…”

Competitive Extraction of Pb2+ by Dicyclohexano-18-crown-6 from Heavy Metal Aqueous Solutions

“…When equilibrium is achieved between an aqueous phase containing a metal ion M m+ and a counteranion Aand an organic phase containing a neutral crown ether L, a crown ether complex ML n A m is considered to be formed (Frensdorff, 1971;Tanigawa et al, 1988) and the overall equilibrium can be expressed by means of the overall equilibrium constant K:…”

“…The very low distribution ratios obtained for Cu 2+ , Co 2+ , and Zn 2+ with benzo-15-crown-5 are not explained by the fit between the carrier cavity and the size of metal ion: other factors, like the substitution groups and the number of oxygen atoms in the crown ether molecule, and also possible changes in the conformation of the macrocycle during complexing, have an important influence on extraction (Izatt et al, 1983(Izatt et al, , 1988Morosanova et al, 1984;Tanigawa et al, 1988).…”