Determination of critical properties for binary and ternary mixtures of short chain alcohols and alkanes using a flow apparatus

• Critical properties of four binary systems and two ternary systems were measured.
• All binary systems show non-ideal behavior especially for mixtures with ethanol.
• All data of binary systems were fitted well with Redlich–Kister equation.
• Critical surfaces of ternary systems were plotted using the Cibulka's expressions.

The critical temperatures and pressures of four binary systems and two ternary systems containing gasoline additives (ethanol + cyclohexane, ethanol + octane, 2-propanol + octane, 2-propanol + decane, ethanol + cyclohexane + octane and 2-propanol + octane + decane) were measured with a low-residence time flow apparatus. The critical properties were determined by observing critical opalescence and phase changes in a quartz glass tube. The expanded uncertainties of critical temperature and pressure were estimated to be less than ±0.4 K and ±0.01 MPa, respectively. The four binary systems show non-ideal behavior especially for ethanol + cyclohexane and ethanol + octane systems. The experimental data of all binary mixtures could be correlated to within 0.06% with the Redlich–Kister equations. Ternary mixtures are newly reported in this work and were correlated with Cibulka's and Singh's expressions.

Experimental critical temperatures for the ethanol (1) + cyclohexane (2) + octane (3) system.Figure optionsDownload as PowerPoint slide