Thermodynamic excesses and the diffusion-controlled relaxation in the liquid system propan-2-ol–cyclohexane

Clusters of propan-2-ol molecules existing in the liquid phase due to hydrogen bonds disintegrate on dilution with cyclohexane. That leads to positive excesses of volume, expansion, compression and enthalpy. ‘Chemical’ and ‘physical’ contributions to the excesses were found by fitting the modified ERAS model to experimental data. The excess volumes and expansions proved to be mainly due to steric mismatch of the two types of molecules. For the same reason, movements of propan-2-ol molecules in dilute solutions are hampered, that is manifested in the ultrasonic relaxation times of nanoseconds order of magnitude.