Isothermal vapor–liquid equilibria of octane with 1-butanol, 2-butanol, or 2-methyl-2-propanol

Isothermal vapor–liquid equilibria were measured for three binary systems of 1-butanol+octane at 373.15 K, 2-butanol+octane at 358.15 K, and 2-methyl-2-propanol+octane at 343.15 K. The measurements were made in a Rogalski–Malanowski type equilibrium still with circulation of both the vapor and liquid phases. Three binary isothermal systems form a maximum pressure azeotrope. The azeotropic data are x1(AZ)=0.519 mole fraction and P(AZ)=75.71 kPa for 1-butanol (1)+octane (2), x1(AZ)=0.750 mole fraction and P(AZ)=63.58 kPa for 2-butanol (1)+octane (2), and x1(AZ)=0.968 mole fraction and P(AZ)=61.18 kPa for 2-methyl-2-propanol (1)+octane (2). The activity coefficients of three binary systems were correlated with the Wilson, modified Wilson, nonrandom two-liquid (NRTL), and UNIQUAC equations.