Thermodynamics of deuterium exchange reactions in water-amine and alcohol-amine systems

Abstract

Vapour pressures and molar excess enthalpies at 298.15 K are reported for the systems H₂O+(C₂H₅)₂NH and D₂O+(C₂H₅)₂NH. They are analysed to give the equilibrium constant and enthalpy of the reaction

                  2(C₂H₅)₂NH(1)+D₂O(1)→2(C₂H₅)₂ND(1)+H₂O(1)

Molar excess enthalpies at 298.15 K of the systems CH₃OH+(C₂H₅)₂NH, CH₃OD+(C₂H₅)₂NH, C₂H₅OH+(C₂H₅)₂NH and C₂H₅OD+(C₂H₅)₂NH are used to obtain enthalpies of the reactions

           (C₂H₅)₂NH(1)+ROD(1)→(C₂H₅)₂ND(1)+ROH(1)  (R = CH₃, C₂H₅)

Thermodynamic properties of various NH/OD exchange reactions are calculated from statistical mechanical equations by use of harmonic frequencies.