Excess enthalpies for (propane + methanol) at the pressure 5 MPa and the temperatures (253.15, 258.15, 263.15, and 273.15) K. The effect of water as an impurity on the (liquid + liquid) equilibria in (propane + methanol)

• Published in: The Journal of chemical thermodynamics Vol. 25; no. 8; pp. 999 - 1004
• Main Authors: Sipowska, J.T., Ott, J.B., Woolley, A.T., Marchant, B.G., Gruszkiewicz, M.S.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.08.1993; Elsevier
• Subjects: Chemical thermodynamics; Chemistry; Exact sciences and technology; General and physical chemistry; Mixtures; Thermodynamic properties; Water; Temperature; Enthalpy; Alcohol; Excess parameter; Experimental study; Inorganic compound; Binary mixture; Additive; Phase separation; Alkane; Thermodynamic properties; Liquid liquid equilibrium; Propane; Organic compounds; Methanol
• ISSN: 0021-9614; 1096-3626
• DOI: 10.1006/jcht.1993.1095

Excess molar enthalpies HEm are reported for {xC3H8 + (1-x)CH3OH} at the pressure 5 MPa and the temperatures (253.15, 258.15 263.15, and 273.15) K. The experimental results are compared with earlier measurements at higher temperatures from which it is shown that HEm and the temperature coefficient CEp. m are much smaller at these lower temperatures. No linear regions in the HEm (x) curves were found at any of these temperatures, indicating that the upper critical solution temperature (UCST) is below 253.15 K. However, addition of mass fraction 5·10-3 of H2O to the methanol resulted in (liquid + liquid) phase separation at T = 253.15 K, suggesting that the much higher UCST reported earlier may have been due to water contamination of the methanol.