Abstract
The formation of carbamic acid from amine and carbon dioxide has been known to play an important physiological role. Because of their instability, however, the details of their formation and chemical properties are not clear. We have previously reported that formation of carbamic acid depends on structure of amine, solvent, and pH. For the formation of carbamic acids, the amino groups need to work as a nucleophilic strong enough to attack carbon dioxide instead of proton. A large amount of carbamic acids can exist in pH ranges that amino groups are able to work as nucleophiles. In aqueous solutions, the formation and breakdown of carbamic acids from amine and carbon dioxide is in equilibrium. Amino acids form zwitterion in aqueous solutions. On addition of base, amino acids take anionic forms, and react with carbon dioxide. We examoned the tome course for the formation of carbamic acid for several amino acids. rate constants on the formation and breakdown of carbamic acids are now under investigation. We wish to report (a) pH dependence of rate constant and (b) side chain effect of amino acids on the formation and breakdown of carbamic acids.
