A distillate containing 45 wt% isopropyl alcohol, 50 wt% diisopropyl ether, and 5 wt% water is obtained from the heads column of an isopropyl alcohol finishing umt. The company desires to recover the ether from this stream by liquid ?liquid extraction in a column, with water, as the solvent, entering the top and the feed entering the bottom so as to produce an ether containing no more than 2.5 wt% alcohol and to obtain the extracted alcohol at a concentration of at least 20 wt%. The unit will operate at 25?C and 1 atm. Using the method of Varteressian and Fenske with a McCabe? Thiele diagram, find how many theoretical stages are required. Is it possible to obtain an extracted alcohol composition of 25 wt%? Equilibrium data are givenbelow.

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PHASE EQUILIBRIUM DATA AT 25°C, 1 ATM Water Phase Ether Phase Wt% Wt% Wt% W1% Wi% Wt% Alcohol Ether Alcohol Ether Water Water 2.4 96.7 0.9 8.1 1.8 90.1 95.7 89.6 3.2 1.1 8.6 1.8 5.0 10.2 1.5 93.6 1.4 88.3 9.3 88.6 69.4 2.1 86.7 80.6 76.0 69.8 11.7 1.6 24.9 38.0 5.7 17.5 1.9 50.2 11.8 21.7 2.3 26.8 45.2 33.6 21.2 3.4 ADDITIONAL POINTS ON PHASE BOUNDARY Wt% Alcohol Wt% Ether Wt% Water 45.37 29.70 24.93 44.55 22.45 33.00 13.42 39.57 47.01 36.23 9.66 54.11 24.74 2.74 72.52 21.33 2.06 76.61 99.4 0.6 0.5 99.5