Thermodynamic properties of organic oxygen compounds. Part XX. The low-temperature heat capacity and entropy of C4 and C5 ketones

The heat capacities of butan-2-one (I), pentan-2-one (II), pentan-3-one (III), and 3-methylbutan-2-one (IV) have been measured by adiabatic calorimetry from 12 to 320°K [360°K for (II)]. Heats of fusion and triple point temperatures were also measured. Transitions in the crystals were observed during measurements on (II) and (III). Entropies of the compounds (liquid) at 298·15°K were: (I) 239·0, (II) 274·1, (III) 266·0, and (IV) 268·5 J deg.–1 mole–1. Entropies in the ideal gas state have been calculated.