A high-precision aneroid static-bomb combustion calorimeter for samples of about 20 mg. The standard enthalpy of formation of bicyclo[3.3.3]undecane

Abstract

An aneroid static-bomb combustion calorimeter has been built and tested. The calorimeter, intended for the combustion calorimetry of relatively volatile hydrocarbons, has been calibrated by the combustion of thermochemical standard benzoic acid. The standard deviation of the mean in a series of eight experiments was less than 0.02 per cent. The energy of combustion of polythene, used to enclose the samples for combustion, has been determined. The standard enthalpy of combustion of bicyclo[3.3.3]undecane has been measured. The quantity ΔH c o = −(1681.2 5 ± 0.4)kcal th mol −1, yields a standard enthalpy of formation ΔH f o(C 11H 20, c) = −(36.4 6 ± 0.4 2) kcal th mol −1. The corresponding gas-phase enthalpy of formation is ΔH f o(C 11H 20, g) = −(21.2 6 ± 0.4 7) kcal th mol −1.