CO2 absorption reaction chemistry
The removal of CO₂ is required in many applications. Eastman AdapT solvents rely on the chemistry of different amine-CO₂ reactions to optimize the performance for each application.
Tertiary amines, such as MDEA, form a bicarbonate with CO₂, which is slowly formed in the amine solution. This is illustrated in the following reaction scheme.
Formation of carbamate
Non-tertiary amines can react much faster with CO₂ through formation of a carbamate. The free proton formed in this reaction may protonate a second amine, which is also a fast step but reduces the absorption capacity. This is illustrated in the reaction scheme.
By selecting the type and concentration of various amines, the CO₂ removal rate and absorption capacity can be adapted. Alongside CO₂ removal efficiency, factors like system corrosion and operational limitations are also important in choosing the right solvent.