Thermodynamics of sublimation,thermophysical and structural aspects of the molecular crystals of fenamates

A method of transfer with an inert carrier gas is used to obtain temperature dependences of pressure vapors. The thermodynamic functions of sublimation processes are calculated for seven molecular crystals that belong to the group of non-steroidal anti-inflammatory drugs: diclofenac, niflumic, flufenamic, tolfenamic, mefenamic, N-phenylanthranilic acids, and diphenylamine. Differential scanning calorimetry is applied to study the melting processes of the selected substances. Single crystal X-ray structural literature data are analyzed, and they are compared with the obtained thermodynamic and thermophysical parameters of sublimation and melting processes. A correlation between the values of the enthalpy of sublimation and the melting temperature under standard conditions is found. The effect of different substituents on the crystal lattice energy of this class of compounds is studied.