Deuterium exchange in water-methanol systems: Calculation of equilibrium constants

1977 ◽  
Vol 30 (11) ◽  
pp. 2371 ◽  
Author(s):  
DV Fenby
Keyword(s):  
Liquid Phase ◽  
Gas Phase ◽  
Isotope Effects ◽  
Equilibrium Constants ◽  
Deuterium Exchange ◽  
Exchange Reactions ◽  
Infrared Studies ◽  
Experimental Values ◽  
Calculated Equilibrium ◽  
Water Alcohol

Equilibrium constants for a number of water-alcohol deuterium exchange reactions in the gas phase are calculated from harmonic frequencies of CH3OH, CH3OD, CD3OH and CD3OD obtained from recent infrared studies. These are combined with vapour-pressure isotope effects to give equilibrium constants for the same reactions in the liquid phase. Calculated equilibrium constants agree well with most published experimental values.

Thermodynamics of Deuterium Exchange Reactions in Water-Thiol and Alcohol-Thiol Systems

1979 ◽  
Vol 32 (4) ◽  
pp. 755 ◽  
Author(s):  
JR Khurma ◽  
DV Fenby
Keyword(s):  
Thermodynamic Properties ◽  
Gas Phase ◽  
Equilibrium Constants ◽  
Deuterium Exchange ◽  
Excess Enthalpies ◽  
Exchange Reactions ◽  
Gas Phase Reactions ◽  
Molar Excess ◽  
Harmonic Frequencies ◽  
Statistical Mechanical

Thermodynamic properties at 298 K are obtained for the deuterium exchange reactions RSH + SHD → O + RSD + H2O RSH + DO2 → O + RSD + HDO RSH + R?OD → O + RSD + R?OH Equilibrium constants and enthalpies of the gas phase reactions with R = R' = CH3 are calculated from statistical mechanical equations using recently published harmonic frequencies. Experimental properties, including the molar excess enthalpies of C2H5SH + CH3OH, C2H5SH + CH3OD, C2H5SH + C2H5OH and C2H5SH + C2H5OD reported in this paper, are used to obtain the equilibrium constants and enthalpies of the liquid and gas phase reactions with R = C2H5, R' = CH3 and C2H5.

Statistical Mechanics of Deuterium Exchange Reactions: Recalculation of Thermodynamic Properties of Water-Methanol Reactions

1979 ◽  
Vol 32 (3) ◽  
pp. 465 ◽  
Author(s):  
JR Khurma ◽  
DV Fenby
Keyword(s):  
Liquid Phase ◽  
Thermodynamic Properties ◽  
Force Field ◽  
Gas Phase ◽  
Vapour Pressure ◽  
The Other ◽  
Exchange Reactions ◽  
Statistical Mechanical ◽  
Experimental Values ◽  
Methanol Reactions

Thermodynamic properties of the reactions CH3OH+HDO → CH3D+H2O CH3OH+D2O → CH3OD+HDO in the gas phase are calculated from statistical mechanical equations. Two sets of calculated harmonic frequencies are used: one obtained from an experimental force field and the other from an ab initio force field. Thermodynamic properties of the corresponding liquid-phase reactions are obtained by combining the gas-phase values with vapour-pressure isotope effect results. The calculated properties are compared with published experimental values.

Vapour Pressure Study of Deuterium Exchange Reactions in Water-Ethanol Systems: Equilibrium Constant Determination

1979 ◽  
Vol 32 (11) ◽  
pp. 2353 ◽  
Author(s):  
RC Phutela ◽  
ZS Kooner ◽  
DV Fenby
Keyword(s):  
Liquid Phase ◽  
Equilibrium Constant ◽  
Vapour Pressure ◽  
Equilibrium Constants ◽  
Deuterium Exchange ◽  
Pressure Measurements ◽  
Exchange Reactions ◽  
Molar Excess ◽  
Constant Determination

A method is proposed for the determination of the equilibrium constants of liquid-phase deuterium exchange reactions from vapour pressure measurements. It is applied to water-ethanol systems to give the equilibrium constant of the reaction 2C2H5OH(l) + D2(l) → 2C2H5OD(l) + H2O(l) The value obtained, 1.05+0.02 at 298 K, is significantly greater than the 'random' value and is more precise and reasonable than a recent calorimetric estimate. Vapour pressures at 298.14 K are reported for the systems H2O+C2H5OH, H2O+C2H5OD, D2O + C2H5OH and D2O + C2H5OD. Molar excess Gibbs functions are obtained from these vapour pressure measurements.

Hydrogen-deuterium exchange reactions of carbanions with deuterated alcohols in the gas phase

1978 ◽  
Vol 100 (9) ◽  
pp. 2921-2922 ◽  
Author(s):  
C. H. DePuy ◽  
Veronica M. Bierbaum ◽  
Gary K. King ◽  
R. H. Shapiro
Keyword(s):  
Gas Phase ◽  
Deuterium Exchange ◽  
Hydrogen Deuterium Exchange ◽  
Exchange Reactions ◽  
Hydrogen Deuterium

Deuterium isotope effects in liquid-liquid phase diagrams: Water + phenol and water + 2-methylpropanoic acid systems

1983 ◽  
Vol 36 (2) ◽  
pp. 215 ◽  
Author(s):  
DV Fenby ◽  
JR Khurma ◽  
ZS Kooner ◽  
RF Smith
Keyword(s):  
Liquid Phase ◽  
Phase Diagrams ◽  
Isotope Effects ◽  
Dispersion Interactions ◽  
Exchange Reactions ◽  
Molar Excess ◽  
Deuterium Isotope Effects ◽  
London Dispersion ◽  
Molar Excess Volumes ◽  
System Water

Phase-separation temperatures Tp have been measured for the systems H2O+C6H5OH, H2O+ C6H5OD, H20+ CsD5OD, D20+ C6H50H, D2O+ C6H5OD, D2O+ C6DsOD, H2O+ (CH3)2CHCO2H and D2O+ (CH3)2CHCO2H. For water+ 2-methylpropanoic acid, the differences in the Tp-x curves for the exchange and no-exchange systems are striking. For water + phenol, on the other hand, the effect of deuterium-exchange reactions on the Tp-x curves is very small. The results for all systems are in accord with the qualitative predictions of the Rabinovich theory, which accounts for deuterium isotope effects in liquid-liquid phase diagrams in terms of hydrogen bond and London dispersion interactions. Molar excess enthalpies and molar excess volumes at 300.15 K are reported for the system water + 2-methylpropanoic acid. The results are compared with those for water + acetic acid.

THE RADIOLYSIS OF ETHANOL: IV. DEUTERATED ETHANOLS IN THE LIQUID AND GAS PHASES

1965 ◽  
Vol 43 (5) ◽  
pp. 1484-1492 ◽  
Author(s):  
J. J. J. Myron ◽  
G. R. Freeman
Keyword(s):  
Liquid Phase ◽  
Gas Phase ◽  
Vapor Phase ◽  
Isotope Effects ◽  
Methane Formation ◽  
Gas Phases ◽  
Product Distributions ◽  
Γ Rays ◽  
The Difference ◽  
Α Particles

The value of G(–ethanol) in the vapor phase is nearly double that in the liquid phase. Part of the difference appears to be due to the recombination of radicals in liquid cages. Ethanol molecules, on the average, break into smaller fragments in the gas than in the liquid phase radiolysis. The isotopic compositions of the hydrogen produced from various deuterated ethanols are consistent with the suggestion that the reaction[Formula: see text]occurs to a significant extent in the liquid but not in the gas phase. This reaction probably involves the shift of a hydrogen atom along a hydrogen bond. The reaction[Formula: see text]does not occur to an appreciable extent in the liquid phase. In the liquid phase the relative contributions of the three different groups in the ethanol molecule to hydrogen production are in the order [Formula: see text] A similar trend occurs in the gas, although the contributions of the three groups are more nearly equal in this phase. Isotope effects, in the range kH/kD = 2.2–3.9 per bond, occur in the methane formation mechanism. The isotope effects are somewhat smaller in the liquid than in the vapor phase and somewhat smaller in the inhibited than in the uninhibited systems. A comparison of product distributions in the liquid and gas radiolyses of several compounds by γ-rays and by α-particles indicates that L.E.T. effects can also occur in the gas phase.

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