2.2. CO2–amine chemistry
Amines (Am) are organic bases that contain at least one nitrogen
with a lone pair of electrons (Fox and Whitesell, 1994). They
are derivatives of NH3 in which one or more hydrogen has been
replaced by an alkyl or aryl substituent. MEA is the most commonly
used amine for CO2 capture applications. In aqueous solution the
nitrogen of sterically unhindered primary and secondary amines
can undergo a direct reaction with CO2 and HCO3
− to form an amine
carbamate species (AmCOO−) (Fernandes et al., 2012a). Sterically
hindered primary and secondary amines do not form stable carbamates
because CO2 is unable to access the nitrogen, and tertiary