Rio, CarolinaRibeiro da Silva, M. A. V.Morais, V. M. F.Matos, M. A. R.2014-10-202014-10-2019961040-0400AUT: CRI01087;http://hdl.handle.net/10400.1/5378The standard (p 0 = 0.1 MPa) molar enthalpies of formation for the liquid 2,3-dimethylpyrazine and trimethylpyrazine and the crystalline 2,3-dimethylquinoxaline and tetramethylpyrazine were derived from the standard molar enthalpies of combustion, in oxygen, atT=298.15 K, measured by static-bomb combustion calorimetry. The standard molar enthalpies of vaporization or of sublimation for the same compounds were determined by Calvet microcalorimetry. Ab initio full geometry optimization at the 3-21G and 6-31G* levels were also performed for all the methylpyrazine isomers. MP2/RHF/3-21G//3-21G and DFT energies were also calculated for all the methylpyrazine isomers, thus allowing us to estimate their isodesmic resonance energies.engMethylpyrazinesEnthalpies of formationRHF calculationsDFT calculationsjournal articlehttp://dx.doi.org/10.1007/BF02275159