摘要:

AbstractFor the interpretation of the data obtained on the extraction of metal complexes to organic solvents from aqueous solutions of low and constant ionic strength, the following minimum number of variables has to be considered: the concentrations of the metal atom (M), main ligand (the base A‐), HA, OH−, H2O, organic solvent molecules (Org) and the temperature. This has been done in an attempt to determine the compostion of the composite complexes of type MAn(OH)p(HA)r(Org)•(H2O)tformed in a given system.In this complex s and t can be determined only in special cases, and it is not possible to distinguish by equilibrium methods between isomers with the same values for x = n + r and y = n + p. These isomers can be represented by the formula M(HA)x(H)−y.It can be shown that in principal a distinction can be made between complexes of the type MAn, MAn(OH)por MAn(OH)p(HA)r.A general method to calculate formation constants for the complex M(HA)x(H)−yfrom extraction data has been developed. It is also shown that from a comparison of the distribution ratios of the metal between water and several different organic solvents it is possible to determine if the metal forms a complex with the organic solvent molecules.The equations have been applied on the distribution of U(VI) and Th between several different organic solvents and water in the presence of acet

ISSN:0165-0513    

DOI:10.1002/recl.19560750702

出版商:WILEY‐VCH Verlag    

年代:1956

数据来源: WILEY

摘要:

AbstractIn spite of many additional complications, the extraction of complexes with inorganic ligands may be treated in the same way as the extraction of complexes with organic ligands. A general method of deducing the formula of the extracted species from studies of partition equilibria is outlined. Application of this method to the partition of tracer concentrations of the indium halide complexes indicates that a number of different species may be extracted. Although the hydrated acido‐complex, HInX4, aq, is the predominant species extracted from halogen acid solutions, significant proportions of the trihalide and complexes or ion‐pairs such as NaInX4partition from halide media at relatively low acidities. The relative extractability of indium into a number of organic solvents follows the same general order for solutions in hydrochloric, hydrobromic and hydriodic ac

ISSN:0165-0513    

DOI:10.1002/recl.19560750703

出版商:WILEY‐VCH Verlag    

年代:1956

数据来源: WILEY

摘要:

AbstractThe extraction method is very useful for studies of the complex formation of metal ions MN+with chelating agents. These reagents are very often organic acids HA which form uncharged complexes MANof very low solubility in water but of appreciable solubility in organic solvents. The distribution ratio, q, of the metal M between the two liquid phases is measured as a function of the concenrtation [A−] of free ligand. Mathemathical treatment of the function log q (log [A−]) very often enables the calculation of at least two parameters a and b for the complex formation. These parameters are defined by the equationsMoreover we can determine the distribution constant of the uncharged com

ISSN:0165-0513    

DOI:10.1002/recl.19560750704

出版商:WILEY‐VCH Verlag    

年代:1956

数据来源: WILEY

摘要:

AbstractThis paper deals with results obtained by the distribution method described in the preceding paperMargareta Dyrssen, The application of solvent extraction to the study of chelate complexes of thorium, p. 748.. This work still being in progress and new data may considerably change the present picture. For those interested in the chemistry of coordination compounds the value of the acid dissociation constants pkaand the mean complexity constants a of ThA4are of the greatest interest. For those interested in metal extraction logKis very importantDefinitions of the complexity constantska,a, andK: cf. M. Dyrssen, p. 750, eqs (8), (2), (11) respectively..It has been generally recognised that when comparing the reaction of a series of chelate ligand ions A−with hydrogen ion and with a metal ion MN+the respective equilibrium constantskaandk1show the same trend; i.e. there appears to be a correlation between acid strength and chelate stabilityH. Rossotti, this volume page 763.. Furthermore it has been observed that 5‐membered chelate rings are more stable than 6‐ or 4‐membered ones. Such generalisations are however not sufficient to explain the behaviour of so different chelating agents as e.g. oxine, cupferron and acetylacetone. Some properties which at the present time seem relevant to the stability of the chelate‐complexes of H+and Th4+will be discu

ISSN:0165-0513    

DOI:10.1002/recl.19560750705

出版商:WILEY‐VCH Verlag    

年代:1956

数据来源: WILEY

摘要:

AbstractThe partial molal entropies of HFeCN6−3and HFedipyCN4−1, the conjugate acids of FeCN6−4and FedipyCN4−2, have been determined relative to FeCN6−3and FedipyCN4−1respectively, and are found to be even more negative than the corresponding S° differences for pairs of oxy‐anions where the charge is also the same, e.g. XO2−1and HXO2−1, etc. The values are examined in relation to an empirical equation for S°, and the possibility that the two conjugate acids have some special structure f

ISSN:0165-0513    

DOI:10.1002/recl.19560750706

出版商:WILEY‐VCH Verlag    

年代:1956

数据来源: WILEY

摘要:

AbstractThe stability constant,KML, of the first metal‐ligand complex, ML, can be related to the stability constant,KHL, of the corresponding proton‐ligand complex, and to the partial molar free energies of the various species in solution. The relationship has been modified for application to mixtures of aqueous and organic solvents. For closely related ligands, logKML, will be an approximately linear function of logKHL. Moreover, logKML, is often a linear function of the molar fraction of the organic component of the mixed solvent.The relationships between the stabilities of very closely related complexes are also discussed, and illustrated with reference to metal complexes of some derivatives of oxine, and to other metal chelates. Steric hindrance to complex formation may cause large deviations from predicted behavi

ISSN:0165-0513    

DOI:10.1002/recl.19560750707

出版商:WILEY‐VCH Verlag    

年代:1956

数据来源: WILEY

摘要:

AbstractBy defining the successive stability constants of metal complex compounds in terms of generalised equilibria it is possible to study metals which do not form simple hydrated metal ions and also non‐water soluble ligands and complexes.If the equilibrium constants are to be interpreted in terms of bond energies etc. it is necessary that the system be defined. That is, the real compositions of the compounds in the equilibrium solution should be known. Some important types of interfering dissociations and reactions can be detected by means of electrical conductivity measurements and some results of such measurements are outlined.The system [PdCl2(n‐C8H17NH2)2] + PBu3n = [PdCl2(n‐C8H17NH2) (PBu3n) ] +C8H17NH2[PdCl2(n‐C8H17NH2) (PBu3n)] + PBu3n = [PdCl2(PBu3n)2] + C8H17NH2has been studied and the free energy changes for the replacement of n‐octylamine by tri‐n‐butylphosphine in the two stages are:ΔG1= −4.56 to −5.08 kcal.ΔG2=

ISSN:0165-0513    

DOI:10.1002/recl.19560750708

出版商:WILEY‐VCH Verlag    

年代:1956

数据来源: WILEY

摘要:

AbstractIn order to obtain some insight into the effect of the dielectric constant of the medium on complex formation, the complex solubilities of silver chloride, silver bromide, silver iodide, and silver thiocyanate in halide or thiocyanate solutions in isodielectric mixtures of water and methanol, ethanol, iso‐propanol, glycerol, dioxane, and acetone have been determined. The complex solubility of the precipitates increased, relative to that in water, with increasing concentration of the organic component in solutions. The lowering of the dielectric constant of the medium caused an increase in the stability of the complex ions presen

ISSN:0165-0513    

DOI:10.1002/recl.19560750709

出版商:WILEY‐VCH Verlag    

年代:1956

数据来源: WILEY

摘要:

AbstractBy emf. measurements of cells of the type Pt‐H2, H+, A−(buffer), KCl, Ag‐AgCl, and extrapolation of the data to infinite dilution, thermodynamic dissociation constants and metal chelate stability constants have been obtained for ethylenediaminetetraacetic and nitrilotriacetic acid. From measurements of this type made over a series of temperatures, the enthalpy and entropy changes associated with complex formation were calculated. In all cases the enthalpy changes were found to be relatively small, while the entropy contributions to the stability of the chelate compounds were found to be considerably greater. The results are interpreted on the basis of the structures of the compounds, and of present theories of chelate ring form

ISSN:0165-0513    

DOI:10.1002/recl.19560750710

出版商:WILEY‐VCH Verlag    

年代:1956

数据来源: WILEY

摘要:

AbstractA modification is given of theBenesi‐Hildebrandequation to determine the equilibrium constant for complex formation from spectrophotometric measurements. Difficulties arising from the use of either concentrations or mole fractions are discusse

ISSN:0165-0513    

DOI:10.1002/recl.19560750711

出版商:WILEY‐VCH Verlag    

年代:1956

数据来源: WILEY