Solvent Effects on Solvent Exchange Reactions at Nickel(II) Centers

1975 ◽  
Vol 53 (5) ◽  
pp. 702-709 ◽  
Author(s):  
Cooper H. Langford ◽  
James P. K. Tong ◽  
André Merbach
Keyword(s):  
Complex Formation ◽  
Linear Relationship ◽  
Solvent Effects ◽  
Solvent Exchange ◽  
Exchange Reactions ◽  
Solvent Dependence ◽  
Leaving Group ◽  
Exchange Kinetics ◽  
Kinetics Of ◽  
Solvent Properties

Several recent correlations relating kinetics of Ni(II) complex formation and solvent exchange to solvent properties are examined after collection of literature and new experiments on solvent exchange kinetics at Ni(II) when onlythesolvent is varied (entering group, leaving group, and nonlabile ligands held constant). The results indicate solvent exchange is remarkably insensitive to bulk solvent. It is suggested that this implies that the interesting correlations of complex formation rates with solvents introduced by Bennetto and Caldin provide a means to study the solvent dependence of the encounter equilibria between a Ni(II) complex and a ligand L. The linear relationship between enthalpies and entropies of activation for reactions at Ni(II) in different media is attributed to the changes in the ligands bound to the Ni(II) center but not undergoing substitution in the reaction observed.

GAS–SOLID EXCHANGE REACTIONS: ZINC VAPOR AND POLYCRYSTALLINE ZINC SULPHIDE

1964 ◽  
Vol 42 (6) ◽  
pp. 1396-1400 ◽  
Author(s):  
E. A. Secco
Keyword(s):  
Zinc Sulphide ◽  
Static System ◽  
Zinc Vapor ◽  
Exchange Reactions ◽  
Polycrystalline Zinc ◽  
Diffusion Controlled ◽  
Fraction Versus ◽  
Exchange Kinetics ◽  
Kinetics Of ◽  
Initial Process

The exchange kinetics of zinc vapor with polycrystalline zinc sulphide, wurtzite structure, have been studied in a static system in the temperature range 720–960 °C.Plots of log10(1−α*), i.e. exchange fraction, versus time reveal two processes. The initial process is a rapid simple exchange, for which the data fit a first-order rate law and which persists to a depth of 15–18 molecular thicknesses. At this depth the second, slower process, which appears to be diffusion-controlled, sets in. Kinetic and structural interpretations of these results along with the existing data on Zn–ZnO exchange are discussed.

Gas–solid exchange reactions: Zinc vapor and polycrystalline zinc selenide

1968 ◽  
Vol 46 (10) ◽  
pp. 1621-1624 ◽  
Author(s):  
E. A. Secco ◽  
Chien-Huo Su
Keyword(s):  
Zinc Selenide ◽  
Static System ◽  
Zinc Vapor ◽  
Exchange Reactions ◽  
Polycrystalline Zinc ◽  
Diffusion Controlled ◽  
Initial Stage ◽  
Exchange Kinetics ◽  
Kinetics Of ◽  
Exchange Data

The exchange kinetics of zinc vapor with polycrystalline zinc selenide have been studied in a static system in the temperature range 720–800 °C.The kinetic data are consistent with a diffusion-controlled process from the initial stage, in contrast with existing exchange data on ZnO and ZnS powders. The diffusion equation is given as:[Formula: see text]

scholarly journals Dependence of displacement of Ca, Md, Fe, K ions from soils from the duration of exposure to H2O and temperature

2021 ◽  
Vol 4 (46) ◽  
pp. 5-5
Author(s):  
Alexander Saakian ◽  
◽  
Keyword(s):  
Complex Formation ◽  
Ion Exchange ◽  
Soil Temperature ◽  
Temperature Influence ◽  
Exchange Reactions ◽  
Podzolic Soils ◽  
Physico Chemical ◽  
Mobility Of Ions ◽  
Ion Desorption ◽  
Kinetics Of

In the conducted studies on sod-podzolic soils and ordinary chernozems, a change in the rate of transition of Ca, Md, Fe, K ions from the soil to H2O at temperatures of 0 and 20º, the interaction time of 1 day and 1 week was established. It is shown that the speed of the processes depends on the combination of temperature and duration of reactions, differs for individual soils, horizons and certain cations. The magnitude of the change in the rate of the processes under consideration does not fully correlate with the physico-chemical and thermodynamic patterns of changes in the mobility of ions in soils depending on humidity and temperature, which is associated with the simultaneous course of ion exchange reactions, complex formation, sedimentation. The necessity of studying the kinetics of processes occurring in the soil for a more correct assessment of the agroecological state of soils is proved. Keywords: KINETICS, SOIL, TEMPERATURE INFLUENCE, ION DESORPTION

Structure of copper(II) ethylenediamine complexes in aqueous and neat ethylenediamine solutions and solvent-exchange kinetics of the copper(II) ion in ethylenediamine as studied by EXAFS and NMR methods

1993 ◽  
Vol 32 (14) ◽  
pp. 3010-3014 ◽  
Author(s):  
Yasuhiro Inada ◽  
Kazuhiko Ozutsumi ◽  
Shigenobu Funahashi ◽  
Sayo Soyama ◽  
Takuji Kawashima ◽  
...  
Keyword(s):  
Solvent Exchange ◽  
Exchange Kinetics ◽  
Nmr Methods ◽  
Kinetics Of
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