Abstract
The separation factor for carbon isotope exchange reaction between CO2 and amine in nonaqueous solvent was related to absorption reaction of CO2 in a solution. The test solutions were mixtures of primary amine (such as butylamine and tert-butylamine) or secondary amine (such as diethylamine, dipropylamine and dibutylamine) diluted with nonpolar solvent (octane or triethylamine) or polar solvent (methanol), respectively.
The isotope exchange reaction consists of three steps related to chemical reaction of CO2 in amine and nonaqueous solvent mixture, namely the reaction between CO2 and carbamic acid, that between CO2 and amine carbamate, and that between CO2 and carbamic ion. Above all, the isotope separation factor between CO2 and carbamic acid had the highest value. The overall separation factor can be higher in amine-nonaqueous solvent mixture where the concentration of carbamic acid becomes higher.
