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

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.

1982 ◽  
Vol 35 (7) ◽  
pp. 1281 ◽  
Author(s):  
JR Khurma ◽  
DV Fenby

Liquid-liquid phase diagrams have been measured for the systems CH3OH+n-C6H14, CH3OH + n-C6D14, CH3OD + n-C6HI4 and CH3OD + n-C6D14. The upper critical solution temperatures of these systems are 306.70, 304.30, 307.59 and 304.84 K, respectively. The results are in accord with the qualitative predictions of the Rabinovich theory, which considers hydrogen bond and London dispersion interactions.


1981 ◽  
Vol 34 (3) ◽  
pp. 635 ◽  
Author(s):  
JR Khurma ◽  
DV Fenby

Molar excess enthalpies of H20 + (CH3),CO, H20 + (CD3),C0, D20 + (CH3)2C0 and D20+ (CD3)2CO at 298.15 K are reported and, in the case of the first system, compared with earlier studies. The results are comparable to those reported for deuterium isotope effects in the molar excess enthalpies of other systems containing (CH3)2CO and (CD3)2CO; they do not suggest the occurrence of any deuterium exchange reactions. A calorimetric study of the mixing of (CD3)2CO with H2O containing a small quantity of NaOH indicates the occurrence of slow, exothermic reaction(s).


2005 ◽  
Vol 238 (2) ◽  
pp. 169-173 ◽  
Author(s):  
Agnieszka Siporska ◽  
Ewa Starościak ◽  
Anna Makowska ◽  
Jerzy Szydłowski

1981 ◽  
Vol 7 (3-4) ◽  
pp. 327-338 ◽  
Author(s):  
D.V. Fenby ◽  
Z.S. Kooner ◽  
J.R. Khurma

1977 ◽  
Vol 30 (11) ◽  
pp. 2371 ◽  
Author(s):  
DV Fenby

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.


1980 ◽  
Vol 33 (11) ◽  
pp. 2349 ◽  
Author(s):  
JR Khurma ◽  
DV Fenby

The molar excess enthalpies of water+acetic acid systems are analysed to give the enthalpy of the reaction ������������� 2HA(1)+D2O(1) → 2DA(1)+H2O(1) (A=CH3COO or CD3COO) the value obtained at 298 K is -0.15�0.04 kJ mol-1. Molar excess enthalpies at 298.15 K are reported for the systems H2O+CH3COOH, H2O+CD3COOD, D2O+CH3COOH and D2O+CD3COOD.


1979 ◽  
Vol 32 (11) ◽  
pp. 2353 ◽  
Author(s):  
RC Phutela ◽  
ZS Kooner ◽  
DV Fenby

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.


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