Thermodynamics of molecular association in binary methanol solutions

1977 ◽  
Vol 30 (6) ◽  
pp. 1241 ◽  
Author(s):  
PP Singh ◽  
BR Sharma ◽  
KS Sidhu
Keyword(s):  
Molecular Species ◽  
Vapour Pressure ◽  
Equilibrium Constants ◽  
Molecular Association ◽  
Pressure Measurements ◽  
Free Energies ◽  
Enthalpy Changes ◽  
Methanol Solutions

This paper deals with isothermal total vapour pressure measurements on methanol (B)+pyridine (A), methanol (B)+β-picoline (A), methanol (B)+N,N-dimethylformamide (A) over the whole range of composition at 303.15 K and the excess Gibbs free energies are evaluated. The data have been analysed in terms of a r-mer-r-mer model of interaction. The equilibrium constants for the various association reactions are evaluated and the enthalpy changes ΔH�l involved in the ABx and A2B molecular species of A and B have also been computed.

Excess free energies of mixing at temperatures below 25°. Isopiestic measurements on the systems H2O-NaCl-Na2SO4 and H2O-NaCl-MgSO4

1971 ◽  
Vol 24 (12) ◽  
pp. 2487 ◽  
Author(s):  
CW Childs ◽  
RF Platford
Keyword(s):  
Free Energy ◽  
Vapour Pressure ◽  
Excess Free Energy ◽  
Pressure Measurements ◽  
Experimental Uncertainty ◽  
Free Energies ◽  
Isopiestic Measurements ◽  
Temperature Range ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing

Isopiestic vapour pressure measurements have been made on the systems H2O-NaCl-Na2SO4 and H2O-NaCl-MgSO4 at 15� and 0�. Excess free energies of mixing the aqueous salts hare been calculated for various ionic strengths, and the results have been compared with those previously obtained at 25�. ��� Within experimental uncertainty the excess free energies of mixing of aqueous NaCl with aqueous Na2SO4 are the same at 0�, 15�, and 25�. However, the excess free energy of mixing aqueous NaCl with aqueous MgSO4 shows differences which may be just larger than experimental uncertainty over the same temperature range.

Determination of the equilibrium constants of water-methanol deuterium exchange reactions from vapour pressure measurements

1980 ◽  
Vol 33 (1) ◽  
pp. 9 ◽  
Author(s):  
ZS Koner ◽  
RC Phutela ◽  
DV Fenby
Keyword(s):  
Equilibrium Constant ◽  
Satisfactory Agreement ◽  
Vapour Pressure ◽  
Equilibrium Constants ◽  
Deuterium Exchange ◽  
Pressure Measurements ◽  
Exchange Reactions ◽  
Molar Excess

The equilibrium constant of the reaction2CH3OH(l) + D2O(l) → 2CH3OD(l) + H2O(l) is obtained from vapour pressure measurements. The value, 1.09k0.02 at 298 K, is in satisfactory agreement with calculated values and with calorimetric estimates. Vapour pressures at 298.14 K are reported for the systems H2O + CH3OH, H2O+CH3OD, D2O + CH3OH and D2O+ CH3OD. Molar excess Gibbs functions are obtained from these vapour pressures.

Equilibrium decomposition pressures of the compounds K2ZrCl6 and K2HfCl6

1978 ◽  
Vol 56 (11) ◽  
pp. 1549-1554 ◽  
Author(s):  
G. J. Kipouros ◽  
S. N. Flengas
Keyword(s):  
Vapour Pressure ◽  
Thermodynamic Data ◽  
Pressure Measurements ◽  
Free Energies ◽  
Chemical Equilibria ◽  
Selective Reactivity ◽  
Alkali Chlorides ◽  
Separating Agent

The chemical equilibria representing the reactions[Formula: see text]and[Formula: see text]were investigated by direct vapour pressure measurements. The thermodynamic data for these reactions, such as free energies and enthalpies of reaction, have been calculated. With reference to the separation of Hf from Zr by a recently developed process based on the selective reactivity of ZrCI4 and HfCl4 vapours with alkali chlorides, it is shown that KCl is a better separating agent than LiCl.

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.

Equilibrium decomposition pressures of the compounds Na2ZrCl6 and Na2HfCl6

1981 ◽  
Vol 59 (6) ◽  
pp. 990-995 ◽  
Author(s):  
G. J. Kipouros ◽  
S. N. Flengas
Keyword(s):  
Vapour Pressure ◽  
Thermodynamic Data ◽  
Pressure Measurements ◽  
Free Energies ◽  
Chemical Equilibria ◽  
Selective Reactivity ◽  
Separating Agents ◽  
Alkali Chlorides

The chemical equilibria representing the reactions[Formula: see text]and[Formula: see text]were investigated by direct vapour pressure measurements and thermodynamic data such as free energies and enthalpies of reaction have been calculated.With reference to the separation of Hf from Zr by a recently developed process based on the selective reactivity of ZrCl4 and HfCl4, vapours with alkali chlorides, it is shown that the efficiency of alkali chlorides as separating agents increases in the order of LiCl → NaCl → KCl.

Equilibrium decomposition pressures of the compounds Cs2ZrCl6 and Cs2HfCl6 and X-ray identification of Na2HfCl6, K2HfCl6, and Cs2HfCl6

1983 ◽  
Vol 61 (9) ◽  
pp. 2183-2188 ◽  
Author(s):  
G. J. Kipouros ◽  
S. N. Flengas
Keyword(s):  
Vapour Pressure ◽  
Thermodynamic Data ◽  
Pressure Measurements ◽  
Free Energies ◽  
Chemical Equilibria ◽  
X Ray ◽  
Selective Reactivity ◽  
Separating Agents ◽  
Alkali Chlorides

The chemical equilibria representing the reactions[Formula: see text]and[Formula: see text]were investigated by direct vapour pressure measurements and thermodynamic data such as free energies and enthalpies of reaction have been calculated. The X-ray powder patterns of the compounds Na2HfCl6, K2HfCl6, and Cs2HfCl6 are also reported.With reference to the separation of Hf from Zr by a recently developed process based on the selective reactivity of ZrCl4 and HfCl4 vapours with alkali chlorides, it is shown that the efficiency of alkali chlorides as separating agents increases in the order CsCl → LiCl → NaCl → KCl.

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