Excess molar enthalpies and excess molar volumes for (propane+propan-1-ol) at a temperature of 348.15 K and at pressures of (5, 10, and 15) MPa

Excess molar enthalpies H-m(E) and excess molar volumes V-m(E) have been determined for (propane + propan-1-ol) at a temperature T = 348.15 K and pressures p = (5, 10, and 15) MPa. Large and positive H-m(E) with a large positive temperature coefficient (excess molar heat capacity) C-p,m(E) are explained in terms of hydrogen bonds being broken when the propan-1-ol is diluted with the propane. The V-m(E) is negative with a large positive pressure coefficient, suggesting that the propane fits into cavities in the hydrogen-bonded structure of the propan-1-ol, with the number of cavities decreasing with increasing pressure. The V-m(E) for (propane + propan-1-ol) is intermediate between the values obtained for (ethane + propan-1-ol) and (butane + propan-1-ol). The relative magnitudes of V-m(E) for these three systems are explained in terms of the relationship of the temperature of measurement to the critical temperatures of the alkanes. (C) 1996 Academic Press Limited