title: An examination of the thermodynamics of fusion, vaporization, and sublimation of (R,S)- and (R)-flurbiprofen by correlation gas chromatography.
abstract: The vaporization, fusion, and sublimation enthalpies of (R,S)- and (R)-flurbiprofen at T = 298.15 K are reported and compared with literature values when available. Correlation gas chromatography experiments were first performed to identify appropriate standards that could be used for materials containing a single fluorine substituent. Subsequent correlations resulted in a vaporization enthalpy for (R,S)-flurbiprofen and (R)-flurbiprofen, ΔH(vap) (298.15 K), of (127.5 ± 5.5) and (127.4 ± 4.7) kJ mol, respectively. Fusion enthalpies, ΔH(fus) (387 K), of (28.2 ± and, ΔH(fus) (381 K), (22.8 ± kJ mol(-1) were also measured by differential scanning calorimetry for the racemic and chiral forms of flurbiprofen. Adjusted to T = 298.15 K and combined with the vaporization enthalpy resulted in sublimation enthalpies, ΔH(sub) (298.15 K), of (155.6 ± 5.8) and (145.1 ± 5.7) kJ mol(-1) for (R,S)- and (R)-flurbiprofen, respectively. The fusion enthalpy measured for the racemic form was in excellent agreement with the literature value, while the sublimation enthalpy varies substantially from previous work. Two weak solid-solid phase transitions were also observed for (R)-flurbiprofen at T = 353.9 K (0.30 ± 0.1) and 363.2 K (0.21 ± 0.03) kJ · mol(-1).
authors.affiliation: Department of Chemistry and Biochemistry, University of Missouri-St Louis, St Louis, Missouri 63121, USA.
authors.forename: Patamaporn
authors.initials: P
authors.lastname: Umnahanant
authors.forename: Darrell
authors.initials: D
authors.lastname: Hasty
authors.forename: James
authors.initials: J
authors.lastname: Chickos
mesh_terms: D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D002849:Chromatography, Gas / Q000379:methods*; D005480:Flurbiprofen / Q000627:therapeutic use*; D013816:Thermodynamics
chemical_list: D000893:Anti-Inflammatory Agents; D005480:Flurbiprofen