Hydrogen-bonding self-association of 1-pentanol controlled by the relativity of interaction energies

Molecular clustering in the liquid state is controlled by the relativity of interaction energies. This means that the clustering is strongly promoted by the coexistence of relatively weakly interacting molecules in the solution. This relativity-controlled clustering was observed for 1-pentanol clustering through the mass spectrometry for clusters isolated from liquid droplets via adiabatic expansion in a vacuum chamber. The 1-pentanol clustering through hydrogen-bonding interaction was significantly promoted by the mixing with water, methanol, acetonitrile or dichloromethane, but it was not promoted by the mixing with 1-propanol or 1, 2-dichloroethane. This solvent effect on the 1-pentanol clustering is explained by the relativity of the 1-pentanol-1-pentanol interaction energy to the 1-pentanol-solvent interaction energy. Thermodynamic analysis on this solvent-induced clustering also supports that the clustering controlled by the relativity of interaction energy is inherent in the liquid state.