Conversion can be increased beyond what is expected by the equilibrium due to the continuous removal of reaction products from the reactive zone.
The introduction of an in situ separation process in the reaction zone or vice versa leads to complex interactions between vapor–liquid equilibrium, mass transfer rates, diffusion and chemical kinetics, which poses a great challenge for design and synthesis of these systems.
Another interesting feature of this system is that it is associated with the formation of a minimum boiling ternary azeotrope of ester, alcohol and water, which is heterogeneous in nature.
The pure ester i.e. butyl acetate, being the least volatile component in the system, is realized as a bottom product.
Removing organic acids from aqueous alcohol (ethanol, isopropanol) in dewatering columns is a simple example.