Saturated vapor pressure of 5,10,15,20-tetraphenylporphyrin (TPP) was determined by Knudsen effusion mass spectrometry technique. The temperature dependence of the vapor pressure is described by the equation ln (p/Pa) = −(23.45 ± 0.26)⋅103/T + (37.32 ± 0.47) in the temperature range 490–615 K. The molar heat capacity measurements of TPP were performed in the temperature range 169–568 K. Quantum-chemical calculations of the structure and force field of the TPP molecule were carried out. These data were used to calculate thermodynamic functions of TPP in the solid and gas states. The enthalpy of sublimation of triclinic form of TPP was determined by the second and third laws of thermodynamics. The value ΔsH° (298.15 K) = 220 ± 12 kJ⋅mol−1 was recommended. The reaction based Feller-Peterson-Dixon approach predicts the gas phase TPP formation enthalpy ΔfH° (298.15 K) = 1004 ± 10 kJ⋅mol−1. A combination of the two last values results in the formation enthalpy of the TPP triclinic form ΔfH° (298.15 K) = 784 ± 15 kJ⋅mol−1.
|Original language||English (US)|
|Journal||Journal of Chemical Thermodynamics|
|State||Published - Jul 8 2020|
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was supported by the Ministry of science and higher education of the Russian Federation in the framework of Government order (№ FZZW-2020-0007). The authors are grateful to Ph.D. N.L. Pechnikova and Dr. V.V. Aleksandriiskii (Research Sharing Center of the Ivanovo State University of Chemistry and Technology) for the synthesis of TPP and the study of the NMR spectrum, respectively, Ph.D. D.V. Tyurin (Department of Chemistry and Technology of Higher Molecular Compounds of the Ivanovo State University of Chemistry and Technology) for the MALDI spectrum of TPP and Ph.D. A.A. Gushchin (Department of Industrial Ecology of the Ivanovo State University of Chemistry and Technology) for the analysis of TPP sample by the high performance liquid chromatography. The authors also thank Ph.D. M.S. Gruzdev (Research Sharing Center of the Institute of Solution Chemistry RAS, Ivanovo) and Ph.D. D.N. Sergeev (Forschungszentrum Jülich, IEK-2, Germany) for measuring the heat capacity of TPP in the temperature ranges 169–302 K and 328–568 K, respectively.