The esterification reaction of methanol and formic acid produces water and methyl formate.
The extent of the reaction is limited by the equilibrium constant, taken to be 5.
This Demonstration plots the residue curve passing through the locator. It also superimposes the bubble temperature distribution, which indicates that the negative azeotrope between water and formic acid is a stable node with the highest boiling temperature (shown in red). There is another nonreactive azeotrope in the system between methanol and methyl formate (a positive azeotrope and an unstable node with a low boiling temperature show in orange). Finally, pure water, methyl formate, methanol, and formic acid are all saddle points. There is only one distillation region in the quaternary diagram.
The transformed compositions of the two azeotropes are: A: 0.10478 and 1.0 B: 0.0865 and 0.0
The Demonstration also displays the iso-temperature curves and the temperature (in °C) at the position of the locator.