Thermochemistry of sarcosine and sarcosine anhydride: Theoretical and experimental studies

Abstract

The standard molar enthalpies of formation, in the gaseous phase, at T=298.15K, of sarcosine, −(388.0±1.0)kJ·mol−1, and sarcosine anhydride, −(334.5±1.6)kJ·mol−1, were calculated by combining, for each compound, the standard molar enthalpy of formation, in the crystalline phase, and the standard molar enthalpy of sublimation, derived from measurements of the standard massic energies of combustion by static bomb combustion calorimetry, and from measurements of vapour pressures by the Knudsen mass-loss effusion method, respectively. The standard (po=0.1MPa) molar enthalpies, entropies and Gibbs functions of sublimation, at T=298.15K, were also calculated. A theoretical study at the G3 and G4 levels has been carried out, and the calculated enthalpies of formation have been compared with the experimental ones.