Question

8.9. Characteristics of an extraction system.
For extracting acetic acid (A) from a dilute water solution (C)
into ethyl acetate (S) at 25 C, estimate or obtain data for (KA)D,
(KC)D, (KS)D, and bAC. Does this system exhibit: (a) high selectivity,
(b) high solvent capacity, and (c) easy solvent recovery? Can you
select a better solvent than ethyl acetate?

Answer 1

Yes Methyl tert-butyl ether(MTBE) can be used as solvent instead of ethyl acetate as a solvent.Feed concentration upto 40% acetic acid can be recovered with MTBE as solvent.

a) Selectivity of a solvent is the ability to separate the components in a given mixture. Yes, this system shows good selectivity compared with solvents like n-butanol , iso-butanol etc.

b) Yes ethyl acetate is a solvent with high solvent capacity . And that's why it's a widely used solvent.

c)As the ethyl acetate forms azeotropic mixture with water separation is difficult with conventional distillation.Membrane methods like dehydration of ethyl acetate by pervaporation etc can be used.