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

Abstract

The equilibrium constant of the reaction

2CH₃OH(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.