Due to the small separation factor of aqueous acetic acid mixtures, to achieve concentrations of more than 90 wt% Acetic acid, simple rectification is not economic. Consequently, an extractive rectification, an azeotropic distillation, or a combination of extraction and azeotropic distillation is chosen to minimize the energy needed for the concentration.
As extractive agents, the following are applicable:
Sulfuric acid (for extractive rectification)
Pfaudler will select the most appropriate process along with its client, based on: