enthalpy of sublimation

The temperature dependence of the saturated vapor pressure and the combustion energy of 2-methyl-5-phenylfuran-3-carboxylic acid were determined by experimental methods. Based on the obtained data, the values of the enthalpies of combustion and formation in the condensed state were calculated. The enthalpy of sublimation was recalculated to 298K. The additive Benson scheme is supplemented with new fragments for calculating the enthalpies of formation in the gaseous state.

Combustion energies of esters (ethyl 6-methyl-2-oxo-4-phenyl-1,2,3,4-tetrahydropyrimidine-5-carboxylate; ethyl 6-methyl-4-(4-methylphenyl)-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate; ethyl 4-(4-methoxyphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate and ethyl 4-(6-methoxyphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate) were experimentally obtained using a bomb calorimetry. According to the experimental data, the enthalpies of combustion and the enthalpies of formation in a solid state were calculated.