The thermodynamic properties of 4-methylphenanthrene

Article abstract of DOI:10.1016/0021-9614(89)90130-4

Measurements leading to the calculation of the ideal-gas thermodynamic properties for 4-methylphenanthrene are reported.Thermochemical and thermophysical properties were determined by adiabatic heat-capacity calorimetry, combustion calorimetry, comparative ebulliometry, and inclined-piston manometry.Results were used to calculate entropies, enthalpies, and Gibbs energies of formation for the ideal-gas state at selected temperatures to 500 K.Group-contribution methods involving comparisons for a series of methyl-substituted aromatic molecules were used to demonstrate the consistency of ideal-gas entropies and the enthalpy of formation determined for 4-methylphenanthrene with literature values for related compounds.The results are shown to be in accord with a barrier to methyl rotation from the literature determined using n.m.r. spectroscopy.