Structural effects on the thermochemical properties of cycloalkanones. III. Enthalpy of combustion, vapour pressures, and enthalpy of sublimation, and standard enthalpy of formation in the gaseous phase of pentacyclo[5.4.0.02,6.03,10.05,9]undecane-8,11-dione

• Published in: The Journal of chemical thermodynamics Vol. 31; no. 2; pp. 263 - 271
• Main Authors: Jiménez, P., Roux, M.V., Dávalos, J.Z., Abboud, J.-L.M., Molina, M.T.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.02.1999; Elsevier
• Subjects: Chemical thermodynamics; Chemistry; Elements, mineral and organic compounds; enthalpy of combustion; enthalpy of formation; enthalpy of fusion; enthalpy of solid–solid transition; enthalpy of sublimation; Exact sciences and technology; General and physical chemistry; pentacyclo[5.4.0.02,6.03,10.05,9]undecane-8,11-dione; strain energy; Thermodynamic properties; enthalpy of combustion; enthalpy of formation; strain energy; enthalpy of sublimation; enthalpy of fusion; pentacyclo[5.4.0.02,6.03,10.05,9]undecane-8,11-dione; enthalpy of solid–solid transition; Heat of combustion; Pentacyclic compound; Vapor pressure; Strain energy; Heat of sublimation; Enthalpy; Diketone; Heat of fusion; Experimental study; Ketone; Phase transformation; Ring strain; Thermodynamic properties; Heat of formation; Organic compounds
• ISSN: 0021-9614; 1096-3626
• DOI: 10.1006/jcht.1998.0450

The standard molar energy of combustion of pentacyclo[5.4.0.02,6.03,10.05,9]undecane-8,11-dione has been determined by using a static bomb calorimeter. The vapour pressure of the compound was measured in the intervalT=325.64 K toT=340.97 K by the Knudsen-effusion technique. Enthalpy of fusion and enthalpy of transition measurements were carried out by differential scanning calorimetry (d.s.c.). From the experimental results of this work, the standard enthalpies of combustion, sublimation, and formation in the crystalline and gaseous state at the temperature 298.15 K have been derived for pentacyclo[5.4.0.02,6.03,10.05,9] undecane-8,11-dione: ΔfHmo(cr) =−(206.2± 3.2) kJ · mol−1, ΔsubHmo= (92.6± 1) kJ· mol−1, ΔfHmo(g) =−(113.6± 3.4) kJ− mol−1. Strain energy due to the presence of the two carbonyl groups in the molecule is estimated by three different methods with consistent results.