The enthalpies of formation of alkyl carbamates: Experimental and computational redetermination

Abstract

In the present work, a redetermination of thermochemical data of methyl carbamate and ethyl carbamate was performed by both experimental and computational techniques. Their gas-phase standard (po=0.1MPa) molar enthalpies of formation, ΔfHmo(g), at T=298.15K, were derived from the standard molar enthalpies of formation, in the crystalline phase, ΔfHmo(cr), and from the standard molar enthalpies of sublimation, ΔcrgHmo at T=298.15K, measured, respectively, by static bomb combustion calorimetry and high temperature Calvet microcalorimetry. The experimental results were compared with computational data, calculated at the G3(MP2)//B3LYP level, as well as with values reported in the literature. At the B3LYP/6-31G(d) level of theory, the molecular structure of both carbamates was obtained.