Extraction of acEtic acid from WatEr Using isopropyl EthEr

69 Unit operations are ubiquitous in any chemical process. One of their main purposes is to achieve separation in order to recycle unconverted reactants or reach product purity specifications. If two phases are brought into intimate contact, a few components migrate from one phase to the other in every stage of the unit. Then, the two phases are separated. When we consider equilibrium-staged separations, we assume that both phases leaving each stage are in equilibrium and one is richer in one or more components. The most common unit operation is distillation. It is used, for instance, to separate crude petroleum into its various fractions such as kerosene and gasoline. In the pharmaceutical industry, liquid-liquid extraction is often employed. For example, antibiotics in aqueous fermentation are recovered using organic solvents. Finally, absorption and stripping are often involved in gas treatment plants—such as units used to remove acid gases (CO2 and H2S) from natural gas. In the present paper, we solve two problems while showing how graphical methods can be used to design the unit operations. The first problem treats liquid-liquid extraction while the second problem deals with binary distillation.