Reconciled thermophysical data for anthracene

Abstract

Anthracene (CAS RN: 120-12-7) is recommended as a primary standard for sublimation enthalpy measurements and it is also frequently used for testing apparatus for vapour pressure measurements. Two recent recommendations by ICTAC for sublimation enthalpy at 298.15 K obtained by extrapolation can be found in the literature. However, no recommended vapour pressure equation and sublimation enthalpy as a function of temperature were reported. The following steps were performed to develop recommended sublimation pressure and enthalpy data for anthracene in the temperature range in which the calibrations are typically performed: (i) analysis and reconciliation of the literature values on vapour pressures and examination of their thermodynamic consistency with related thermal properties; (ii) new extensive vapour pressure measurements in the temperature range (343–373) K; (iii) calculation of ideal-gas thermodynamic properties combining statistical thermodynamics and quantum chemistry methods, and (iv) multi-property correlation of selected vapour pressure and thermal data. The quality and range of available data needed for the multi-property correlation allowed to establish the recommended sublimation pressure equation in the temperature range (200–373) K while at higher temperatures and for the liquid phase only tentative data are provided. Recommended values at 298.15 K are (0.91 ± 0.09) mPa for sublimation pressure and (101.01 ± 0.52) kJ·mol−1 for sublimation enthalpy; the recommended enthalpy of sublimation at 0 K is (104.4 ± 0.9) kJ mol−1. Based on the recommended sublimation pressures, super cooled liquid vapour pressures required for environmental modeling were also calculated.