Reconciliation of Experimental and Computed Thermodynamic Properties for Methyl-Substituted 3-Ring Aromatics. Part 2: 3 Methylphenanthrene
Andrei F. Kazakov, Eugene Paulechka, Robert D. Chirico
Measurements leading to the calculation of thermodynamic properties in the ideal-gas state for 3-methylphenanthrene (Chemical Abstracts registry number [832-71-3]) are reported. Experimental methods were adiabatic heat-capacity calorimetry, differential scanning calorimetry (d.s.c.), comparative ebulliometry, inclined-piston manometry, vibrating-tube densitometry, and oxygen bomb calorimetry. The critical temperature, critical pressure, and critical density were estimated based on these measurements. Molar thermodynamic functions for the condensed and ideal-gas states were derived from the experimental results. Statistical calculations were performed based on molecular geometry optimization and vibrational frequencies using B3LYP hybrid density functional theory with the def2-QZVPD basis set. Differences between computed and experimentally derived ideal-gas entropies are larger than the experimental uncertainties, but good accord is achieved if the two lowest-frequencies vibrational modes are assumed to be coupled, as was found for 9-methylanthracene in Part 1 of this pair of articles. The enthalpy of formation for 3-methylphenanthrene in the ideal-gas phase was computed with an atom-equivalent based protocol described recently, and excellent agreement with the experimental value is shown. Experimental results are compared with literature values, where possible.
, Paulechka, E.
and Chirico, R.
Reconciliation of Experimental and Computed Thermodynamic Properties for Methyl-Substituted 3-Ring Aromatics. Part 2: 3 Methylphenanthrene, Journal of Chemical and Engineering Data, [online], https://doi.org/10.1021/acs.jced.1c00908, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=933618
(Accessed June 9, 2023)