Determination of molar enthalpy of sublimation in case of orotic acid as obtained from experimental and computational data

Highlights: • The ${\Delta }_{\mathrm{sub}}{H}_m^0\left(T_m\right)$ of orotic acid was determined from Knudsen effusion mass spectrometry. • The ${\Delta }_{\mathrm{sub}}{H}_{298}^0$ was predicted from both group contribution and electrostatic potential methods. • Solid phase enthalpy of formation was estimated. Saturated vapor pressure, ln(p/Pa) = (−21316 ± 511)/(T/K)+(41.64 ± 0.11), and enthalpy of sublimation of orotic acid, ${\Delta }_{\mathrm{sub}}{H}_m^0\left(T_m\right)$ = 177 ± 4 kJ/mol, were determined by means of Knudsen effusion mass spectrometry in the temperature range of 423÷493 K. The computational approaches supported the experimental results reported. The theoretical estimation of the gas-phase enthalpy of formation for orotic acid was done with different working reactions used.