Chapter 6, Problem 6.98P

Benzene and hexane are being considered as solvents to extract acetic acid from aqueous mixtures. At 30°C, distribution coefficients for the two solvents are K_B = 0.098 mass fraction acetic acid in benzene/mass fraction acetic acid in water and K_H = 0.017 mass fraction acetic acid in hexane/mass fraction acetic acid in water.

(a) Based on the distribution coefficients only, which of the two solvents would you use and why? Demonstrate the logic of your decision by comparing the quantities of the two solvents required to reduce the acetic acid content in 100 kg of an aqueous solution from 30 wt% to 10 wt%.

(b) What other factors may be important in choosing between benzene and cyclohexane?