Determination of the Heat of Formation of Hexafluorobenzene

Abstract

A new method has been developed for determining the heat of combustion of perfluoro aromatic compounds. The basic differences from previous methods are that no auxiliary substance is used and no water is present in the bomb. The combustion of hexafluorobenzene in a platinum lined bomb yields CO2, CF4, and F2. Visual inspection and the material balance indicate that complete combustion is obtained. The value of [Formula: see text] obtained by this method is −224.0 ± 2.0 kcal/mol. Recalculation of the result of Cox etal. (1, 2) obtained from combustion of C6F6 in mylar bags in the presence of hydrocarbon oil and water leads to[Formula: see text]