Journal of Chemical Thermodynamics, Vol.43, No.9, 1306-1314, 2011
Standard molar enthalpies of formation of 1-and 2-cyanonaphthalene
The standard (p degrees = 0.1 MPa) molar enthalpies of formation, in the crystalline state, of the 1- and 2-cyanonaphthalene were derived from the standard molar energies of combustion, in oxygen, at T = 298.15 K, measured by static-bomb combustion calorimetry. Vapor pressure measurements at different temperatures, using the Knudsen mass loss effusion technique, enabled the determination of the enthalpy, entropy, and Gibbs energy of sublimation, at T = 298.15 K, for both isomers. The standard molar enthalpies of sublimation, at T = 298.15 K. for 1- and 2-cyanonaphthalene, were also measured by high-temperature Calvet microcalorimetry. [GRAPHICS] Combining these two experimental values, the gas-phase standard molar enthalpies. at T = 298.15 K, were derived and compared with those estimated by employing two different methodologies: one based on the Cox scheme and the other one based on G3MP2B3 calculations. The calculated values show a good agreement with the experimental values obtained in this work. (C) 2011 Elsevier Ltd. All rights reserved.
Keywords:Energy of combustion;Enthalpy of sublimation;Enthalpy of formation;Combustion calorimetry;Calvet microcalorimetry;Knudsen effusion;Vapor pressure;Entropy of sublimation;Gibbs energy of sublimation;Cyanonaphthalenes