Partition Function Ratios and Equilibrium Constants for Oxygen-18 Exchange Reactions.

1962 ◽  
Vol 7 (2) ◽  
pp. 240-242 ◽  
Author(s):  
S. C. Saxena ◽  
D. N. Bhatnagar ◽  
S. Ramaswamy
Keyword(s):  
Partition Function ◽  
Equilibrium Constants ◽  
Exchange Reactions

THERMODYNAMIC PROPERTIES AND GEOCHEMISTRY OF ISOTOPIC COMPOUNDS OF SELENIUM

1962 ◽  
Vol 40 (2) ◽  
pp. 367-375 ◽  
Author(s):  
H. R. Krouse ◽  
H. G. Thode
Keyword(s):  
Partition Function ◽  
Kinetic Isotope Effect ◽  
Chemical Reduction ◽  
Equilibrium Constants ◽  
Elemental Selenium ◽  
Exchange Reactions ◽  
Kinetic Isotope ◽  
Naturally Occurring ◽  
Selenium Isotope ◽  
Selenium Isotopes

Using "normal vibration equations" and statistical mechanics, the isotopic vibrational frequencies and the partition function ratios for various Se76- and Se82-containing compounds have been calculated. The equilibrium constants for selenium isotope exchange reactions derived from these partition function ratios indicate that noticeable fractionation of selenium isotopes can be expected in the laboratory and in naturally occurring processes.The Se82/Se76 ratios for 16 natural samples have been compared mass spectrometrically. Variations of up to 1.5% found in this ratio are discussed.A kinetic isotope effect of 1.5% found in a chemical reduction of selenite ion to elemental selenium is also discussed.

THERMODYNAMIC PROPERTIES OF ISOTOPIC COMPOUNDS OF SULPHUR

1950 ◽  
Vol 28b (9) ◽  
pp. 567-578 ◽  
Author(s):  
A. P. Tudge ◽  
H. G. Thode
Keyword(s):  
Partition Function ◽  
Thermodynamic Properties ◽  
Statistical Mechanics ◽  
Equilibrium Constants ◽  
Sulphur Isotopes ◽  
Exchange Reactions ◽  
Sulphur Compounds ◽  
Exchange Constants

Using the well known methods of statistical mechanics, partition function ratios for many isotopic sulphur compounds have been calculated. These partition function ratios are used to determine equilibrium constants for many possible exchange reactions involving the isotopes of sulphur. The results indicate that considerable fractionation of the sulphur isotopes can be expected in laboratory and natural occurring processes. The predicted exchange constants are discussed in the light of recent results on the distribution of the sulphur isotopes in nature.

FRACTIONATION OF GERMANIUM ISOTOPES IN CHEMICAL REACTIONS

1964 ◽  
Vol 42 (8) ◽  
pp. 1971-1978 ◽  
Author(s):  
H. M. Brown ◽  
H. R. Krouse
Keyword(s):  
Partition Function ◽  
Isotope Exchange ◽  
Isotope Fractionation ◽  
Kinetic Isotope Effect ◽  
Chemical Reduction ◽  
Isotope Effects ◽  
Equilibrium Constants ◽  
Kinetic Isotope Effects ◽  
Exchange Reactions ◽  
Kinetic Isotope

Isotopic vibrational frequencies and the corresponding partition-function ratios for several compounds containing Ge70 and Ge76 have been calculated at various temperatures. The theoretical equilibrium constants for germanium isotope-exchange reactions derived from these partition-function ratios indicate that noticeable germanium isotope fractionation might be effected with laboratory reactions. Calculated kinetic isotope effects in the breaking of diatomic bonds also predict observable alterations of the Ge70/Ge76 ratio.A kinetic isotope effect of 1.0% observed in the chemical reduction of GeO2 to GeO is discussed.

scholarly journals Isotopic Partition Function Ratios Involving H2, H2O, H2S, H2Se, and NH3

1973 ◽  
Vol 28 (2) ◽  
pp. 129-136 ◽  
Author(s):  
J. Bron ◽  
Chen Fee Chang ◽  
M. Wolfsberg
Keyword(s):  
Partition Function ◽  
Least Squares ◽  
Gas Phase ◽  
Isotopic Exchange ◽  
Equilibrium Constants ◽  
Heavy Atom ◽  
Harmonic Approximation ◽  
Ideal Gas ◽  
Correction Factors ◽  
Exchange Reactions

Ideal gas phase isotopic partition function ratios involving both deuterium and tritium substitution for hydrogen and also heavy atom substitution in H2, H2O, H2S, H2Se, and NH3 have been calculated at a number of temperatures. The results have been least squares fitted to a five term series in powers of (300/T). Various correction factors to the harmonic approximation were considered in the calculation of the partition function ratios. It is demonstrated that the tabulated ratios can be used to calculate equilibrium constants for isotopic exchange reactions.

A nuclear magnetic resonance study of the kinetics and equilibria for the oxidation of penicillamine and N-acetylpenicillamine by glutathione disulfide

1984 ◽  
Vol 62 (9) ◽  
pp. 1672-1680 ◽  
Author(s):  
Dallas L. Rabenstein ◽  
Yvon Theriault
Keyword(s):  
Equilibrium Constants ◽  
Reducing Power ◽  
Thiol Group ◽  
Nuclear Magnetic Resonance Study ◽  
Second Step ◽  
Glutathione Disulfide ◽  
Exchange Reactions ◽  
H Nmr ◽  
Mixed Disulfide ◽  
Ph Range

The kinetics and equilibria of the oxidation of penicillamine by glutathione disulfide to form, in the first step, penicillamine–glutathione mixed disulfide and glutathione and, in the second step, penicillamine disulfide and glutathione have been studied over the pH range 4–9 by 1H nmr. The reactive species are found to be penicillamine with its amino group protonated and its thiol group deprotonated and glutathione disulfide and penicillamine–glutathione mixed disulfide with their two amino groups protonated. The rate and equilibrium constants for the first step are much larger than those for the second step, indicating a small tendency for penicillamine to form its symmetrical disulfide by thiol/disulfide exchange reactions. This and the smaller reducing power of penicillamine as compared to glutathione are attributed to steric hindrance from the methyl groups adjacent to the sulfur. The kinetics and equilibria of the oxidation of N-acetylpenicillamine by glutathione disulfide were studied at neutral pH. Conditional equilibrium and rate constants for the oxidation of penicillamine by glutathione disulfide at pH 7.4 are presented and discussed in terms of the metabolism of penicillamine.

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