Standard Thermodynamic Functions from Experimental Heat Capacity Measurements of Two Polycyclic Aromatic Hydrocarbons, Indeno[1,2,3-cd]pyrene and Benzo[ghi]perylene

Abstract

Temperature dependencies of heat capacity of two polycyclic aromatic hydrocarbons, indeno[1,2,3-cd]pyrene and benzo[ghi]perylene, in a crystalline state were investigated using adiabatic calorimetry at T = 6.1 to 325.2 K and at T = 5.7 to 329.1 K, respectively. Smoothed molar heat capacity, C p, m o (T), values at T = 0 to 320 K are presented along with values for the standard thermodynamic functions: molar third-law entropy,Using the C p, m o (T) data, the standard molar third-law entropies at T = 298.15 K, S m o , are calculated as 273.3 ± 1.9 J•K −1 mol −1 for indeno[1,2,3-cd]pyrene and 278.6 ± 1.7 J•K −1 mol −1 for benzo[ghi]perylene. It was shown that the relative expanded uncertainties for thermodynamic functions in this work are lower compared to previously published data.

Thermodynamic Properties of Thioxanthone between 80 and 540 K

“…The thermodynamic parameters of aromatic and heteroaromatic molecules have been studied in-depth from the beginning of the 20th century to the recent years. − On the one hand, structural rigidity makes them a primary model system for the development and validation of ab initio and empiric approaches for calculating heat capacities, − Gibbs energies/entropies/enthalpies of fusion, sublimation, and crystal structure prediction . On the other hand, aromatic/heteroaromatic molecules, including the title compound thioxanthone (THX), are scaffolds or precursors for numerous pharmaceuticals, dyes, components of optoelectronics, and so forth, having a significant impact on the environment itself.…”