Thermodynamics Research Center / ThermoML | Thermochimica Acta

ABSTRACT

Temperature dependencies of saturated vapor pressure for i-acetamidobenzoic acids (i=2-, 3- and 4-) were obtained by flow inert gas-carrier transfer method. Thermodynamic parameters of sublimation were calculated for 2-acetamidobenzoic acid (2-AcAm-BA), 3-acetamidobenzoic acid (3- AcAm-BA) and 4-acetamidobenzoic acid (4-AcAm-BA) (2-AcAm-BA: =54.4 kJ*mol-1; = 116+-1 kJ*mol- 1; =205+-4 J*K-1*mol-1; 3-AcAm-BA: =73.2 kJ*mol-1; = 137+-1 kJ*mol-1; =215+-4 J*K-1*mol-1; 4- AcAm-BA: =72.3 kJ*mol-1; = 138+-1 kJ*mol-1; =221+-8 J*K-1*mol-1). Thermochemical parameters of fusion process for investigated objects were obtained, and vaporization enthalpies were estimated from fusion and sublimation enthalpies. The thermal data obtained in all experiments was used to find relationships between the thermal properties of these compounds and other benzoic acid derivatives and their structural properties. A correlation between enthalpy of sublimation and melting point was obtained. The influence of size and position of substituents on crystal lattice energy was discussed.