Measurements of heats of combustion by flame calorimetry. Part 7.—Chloromethane, chloroethane, 1-chloropropane, 2-chloropropane
A flame calorimeter, designed to measure the heats of combustion of gaseous chloroalkanes, is described and the following heats of combustion to give products CO2(g) and HCl (600 H2O)(l) at 25°C and 1 atm are reported: ΔH°c(chloromethane, g)=–764.01±0.50 kJ mol–1, ΔH°c(chloromethane, g)=–1413.05±0.59 kJ mol–1, ΔH°c(1-chloropropane, g)=–2072.11±0.79 kJ mol–1, ΔH°c(2-chloropropane, g)=–2059.62±0.79 kJ mol–1. The derived heats of formation agree with those obtained from studies of equilibria involving alkenes, hydrogen chloride and chloroalkanes, but disagree with those obtained by other calorimetric methods. The heats of formation of chloroalkanes are discussed in terms of the Allen bond-energy scheme.