Measurements of heats of combustion by flame calorimetry. Part 8.—Methane, ethane, propane, n-butane and 2-methylpropane
The heats of combustion of the gaseous alkanes, C1 to C4, have been measured at 25°C and 1 atm pressure using a flame calorimeter. ΔH°c(methane, g)=–890.71 ± 0.38 kJ mol–1, ΔH°c(ethane, g)=–1560.69 ± 0.25 kJ mol–1, ΔH°c(propane, g)=–2219.17 ± 0.46 kJ mol–1, ΔH°c(n-butane, g)=–2877.54 ± 0.63 kJ mol–1, ΔH°c(2-methylpropane, g)=–2869.00 ± 0.59 kJ mol–1. The derived heats of formation differ slightly from the previously accepted values as reported in the Americal Petroleum Institute Research Project 44 Tables, and are in better accord with the requirements of the Allen bond-energy scheme.