Measurements of heats of combustion by flame calorimetry. Part 4.—n-Pentane, isopentane, neopentane

Abstract

The heats of combustion of the isomeric pentanes have been measured in the gaseous state at 25°C and 1 atm pressure in a flame calorimeter: ΔH^o_c(n-pentane, g)=–844·99±0·23 kcal mole^–1, ΔH^o_c(isopentane, g)=–843·31±0·22 kcal mole^–1, ΔH^o_c(neopentane, g)=–839·88±0·23 kcal mole^–1. These results were used to derive the heats of formation of each of the pentanes. The heats of isomerization of the pentanes have been discussed in terms of the Allen bond-energy scheme.