THE STANDARD MOLAR ENTHALPY OF FORMATION OF 2-CHLORODIBENZO-P-DIOXIN

The standard molar energy of combustion of crystalline 2-chlorodibenzo -p-dioxin was determined by rotating-bomb calorimetry: Delta(c)U degre es(m) = -(5573.6 +/- 2.8) kJ . mol(-1). The standard molar enthalpy of sublimation was measured in a Calvet microcalorimeter: Delta(sub)H de grees(m) = (97.24 +/- 0.55) kJ . mol(-1). Using these results, the val ues of the standard molar enthalpies of formation of 2-chlorodibenzo-p -dioxin in the crystalline and gaseous states were found to be -(171.3 +/- 3.2) kJ . mol(-1) and -(74.1 +/- 3.3) kJ . mol(-1), respectively. (C) 1996 Academic Press Limited