Isentropic compressibility behaviour of dilute solutions of ethyl-alcohol in water

Summary The adiabatic compressibility of ethanol-water mixtures was measured as a function of temperature and cosolvent concentration; the measurements were carried out at 5°C intervals over the range (10⋎40) °C, paying particular attention to the water-rich region (mole fraction of cosolventx ₂<0.25). The observed concentration dependencies of the adiabatic compressibility in the low-concentration range were well explained if we consider the existence in the mixture of local structures with a composition that is close to ethanol-17 H₂O like that of solid clathrate hydrate of type II. A simple model, involving the solutesolvent interactions and the molecular aggregation of the solute, is used to explain the observed behaviour. To speed up publication, the author of this paper has agreed to not receive the proofs for correction.