Substitution on Trivalent Metal Ions

Kinetic data on ligand substitution of Group III metal ions, including isotopic exchange studies of tris()5-diketonato) complexes in various solvents. 

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Ligand Substitution on Complexes of Trivalent Metal Ions and Metal Ions of Higher Valency... 

Investigation of the details of this system indicate that at low metal-ion loading the extractant dependence from (1 M lactic acid-0.05 M DTPA) is lowered to 2.1-2.9, dependent on the metal ion. Concentration isotherms for the extraction of lanthanum from lactic acid solutions, with and without DTPA present, indicate that saturation occurs at 1.5 equivalents of lanthanum per mol of extractant monomer, interpreted by the authors as indicative of the extraction of one mol of lactate per extracted metal ion. This observation is supported by actual measurement of extracted lactate concentration. Lactic acid is not extracted by HDEHP in the absence of lanthanum. This separation process has acquired the acronym TALSPEAK (trivalent-actinide/lanthan-ide separation by phosphorus reagent extraction from aqueous komplexes). The generic applicability of the concept is demonstrated by the work of Baybarz (1965), who finds only slightly reduced efficiency upon substitution of 2-ethyl(hexyl)phenylphos-phonic-acid/diethyl benzene for HDEHP/DIPB. 

Mixed oxides derived from thermal decomposition of LDHs have acid-base properties that influence the catalytic behavior of these materials and depend on the molar ratio Mii/m" ions, their diameters, charge, calcination temperature, and synthesis methods [50, 51]. The acid-base centers are highly active centers that participate in numerous reactions. These properties can be modified by the variation of the M /M molar ratio, by isomorph substitution of a part of M that are present in the structure with other divalent metal ions (such as NT, Be, Co, Zn +, Cu +, Mn +, Cr +, and Fe " ) and by isomorph substitution of a part of M" that are present in the structure with other trivalent metal ions (e.g. Ga T Fe T Co T NTT Mn T V T In T Rh T Ru ") [2]. With the increase of the M cation presence the amount of acid centers also increases in mixed oxides. Acidity depends on the nature of the M cations, for instance AP+ cations exhibit higher acidity than Fe +cations [1]. After thermal decomposition of LDHs, mixed oxides are formed that present solid bases. The alkalinity level depends on the synthesis method. Application of the coprecipitation and sol-gel methods leads to the formation of mixed oxides that have base centers of Lewis type with medium strength... 

G. Ligand Substitution on Octahedral Trivalent Transition Metal Ions... 

Ligand Substitution on Complexes of the Trivalent Main Group Metal Ions... 

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