The Effect of Pressure on LLE

All of the information presented so far in this chapter is practically independent of the system pressure, as long as the pressure is above the boiling-point pressure of the mixture. The reason, as shown in Chapter 7, is that change in fugacity with pressure is given by Eqs. 7.6 and 7.14, which show that 

FIGURE 11.8 Calculated values of. gmixture— iS° — (RThiXi) + X (/Jrin y,) for water and -butanol at 92 °C, based on the van Laar equation, with constants based on VLE measurements, and the straight line tangent to the curve in two places. 

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