Control by Tray Temperature of Extractive Distillation

Separation by simple distillation of formic acid (HFo) from acetic acid (HAc) in the presence of water is very difficult because of the azeotropic boiling mixture formed. As a result the separation in this application is done by extractive distillation using heptanoic acid as the high boiling extracting agent or solvent (U.S. Patent No. 4, 692, 219).