The enthalpy of vaporization and sublimation of corannulene, coronene, and perylene at T=298.15 K

The sublimation enthalpy of corannulene Delta(cr)(g)H(m) (298.15 K) has been measured by head space analysis and by combining the fusion and vaporization enthalpies. A mean value of (118.3 +/- 3.3) kJ . mol(-1) was obtained. The vaporization enthalpies of perylene and coronene were also measured by correlation gas chromatography. Combining the vaporization enthalpy of perylene with the fusion enthalpy adjusted to T = 298.15 K affords a sublimation enthalpy at 298.15 K of (138.1 +/- 6.2) kJ . mol(-1). This value permits a distinction to be made between several discordant sublimation enthalpies in the literature. The vaporization enthalpy of coronene measured in this work permits an identification of the most probable sublimation enthalpy value among a series of varying literature values. A value of (155 +/- 7.0) kJ . mol(-1) is recommended for Delta(cr)(g)H(m) (298.15 K) of coronene. The new data reported here complete the experimental determination of gas-phase enthalpy of formation values. Delta(f)H(m)(o) (g, 298.15 K): for corannulene (460.6 +/-6.5) kJ . mol(-1), perylene (319.4 +/- 2.2) kJ . mol(-1), and coronene (307.5 +/- 9.8) kJ . mol(-1). (C) 2002 Elsevier Science Ltd. All rights reserved.