Heats of sublimation of some cage hydrocarbons by a temperature scanning technique

The heats of sublimation of some cage hydrocarbons and their derivatives have been measured as part of a programme for the determination of the gas phase heats of formation of these compounds. The technique used is based upon a simple modification of a commericial gas chromatograph. The concentration of organic vapour in an inert gas steam is measured by a flame ionisation detector whilst the temperature of gas stream and sample is linearly increased. The resulting plot of vapour pressure against temperature is used to calculate the heat of sublimation using the Clausius–Clapeyron equation.