Standard molar enthalpies of formation of some methylfuran derivatives

The standard (p(o) = 0.1 MPa) molar enthalpies of formation D(f)H(m)(o) (I), of the liquid 2-methylfuran, 5-methyl-2-acetylfuran and 5-methyl-2-furaldehyde were derived from the standard molar energies of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry. The Calvet high temperature vacuum sublimation technique was used to measure the enthalpies of vaporization of the three compounds. The standard (p(o) = 0.1 MPa) molar enthalpies of formation of the compounds, in the gaseous phase, at T = 298.15 K have been derived from the corresponding standard molar enthalpies of formation in the liquid phase and the standard molar enthalpies of vaporization. The results obtained were -(76.4 +/- 1.2), -(253.9 +/- 1.9), and -(196.8 +/- 1.8) kJ mol(-1), for 2-methylfuran, 5-methyl-2-acetylfuran, and 5-methyl-2-furaldehyde, respectively.