A binary liquid system exhibits LLE at 25°C. Determine from each of the following sets of miscibility data estimates for parameters A12 and A21 in the Margules equation at 25°C: (a) x1 α = 0.10, x1 β = 0.90; (b) x1 α = 0.20, x1 β = 0.90; (c) x1 α = 0.10, x1 β = 0.80.

(a) - A12 = A21 = 2.747

(b) - A12 = 2.148; A21 = 2.781

(c) - A12 = 2.781; A21 = 2.148

Explanation:

(a) - x1 (a) = 0.1 | x2 (a) = 0.9 | x1 (b) = 0.9 | x2 (b) = 0.1

LLE equations:

x1 (a) * γ1 (a) = x1 (b) γ1 (b)

x2 (a) * γ2 (a) = x2 (b) γ2 (b)

A12 = A21 = 2.747

(b) - x1 (a) = 0.2 | x2 (a) = 0.8 | x1 (b) = 0.9 | x2 (b) = 0.1

LLE equations:

x1 (a) * γ1 (a) = x1 (b) γ1 (b)

x2 (a) * γ2 (a) = x2 (b) γ2 (b)

A12 = 2.148; A21 = 2.781

(c) - x1 (a) = 0.1 | x2 (a) = 0.9 | x1 (b) = 0.8 | x2 (b) = 0.2

LLE equations:

x1 (a) * γ1 (a) = x1 (b) γ1 (b)

x2 (a) * γ2 (a) = x2 (b) γ2 (b)

A12 = 2.781; A21 = 2.148