Phase change enthalpies of some monosubstituted derivatives of adamantane: an experimental and theoretical study.

The phase change energetics of adamantane, 1-adamantanemethanol, 1-adamantanethanol, 1-adamantanecarboxylic acid, and 1-adamantaneacetic acid is reported. To conduct the study of the compounds' phase changes, calorimetric techniques and theoretical methodologies were applied. Mole fraction purities, enthalpies, fusion temperatures, and solid phase heat capacities were obtained using differential scanning calorimetry. Enthalpies of sublimation were determined from measurements of mass loss rate and the Clausius-Clapeyron and Langmuir equations, i.e., through thermogravimetric analysis. The gas-phase heat capacities of all stable conformers of the adamantane derivatives at different temperatures were estimated using harmonic oscillator approximation. Finally, the molecular interactions of the adamantane derivatives are discussed. [ABSTRACT FROM AUTHOR]