Structural effects on the thermochemical properties of cycloalkanones .1. Enthalpy of combustion, vapour pressures, and enthalpy of sublimation, and standard enthalpy of formation in the gaseous phase of cyclododecanone

The energy of combustion of cyclododecanone has been determined using a static bomb calorimeter. The vapour pressure of the compound was measured over a temperature interval of 18 K, by the Knudsen-effusion technique. Heat capacity measurements between T = 270 K and T = 328 K were also carried out by d.s.c. From the experimental results of this work, the following standard molar enthalpies of combustion, sublimation, and formation for cyclododecanone in the crystalline and gaseous state at the temperature T = 298.15 K have been derived: Delta(f)H(m)(o)(cr) = -(442.5 +/- 3.1) kJ . mol(-1); Delta(sub)H(m)(o) = (83.2 +/- 0.3) kJ . mol(-1); and Delta(f)H(m)(o)(g) = -(359.3 +/- 3.1) kJ . mol(-1). (C) 1996 Academic Press Limited