Heats of mixing of the partially miscible liquid system cyclohexane + methanol

Abstract

The molar excess enthalpies of cyclohexane + methanol were systematically measured with a Picker flow microcalorimeter operated in the discontinuous mode at 298.15, 303.15, 308.15, 313.15, 318.15 and 323.15K. Our measurements are higher than the literature data. This work shows that molar excess enthalpies increase with temperatures, an the straight segments of the excess enthalpy curves in the mid region become shorter with increasing temperature. At 323.15K the curve become one of a miscible liquid system, and the position of the maximum value is at x=0.6. In addition, the calorimetric measurement can be used to determine the compositions of two immiscible phases for the binary mixture.