Chemical Engineering Journal, Vol.307, 56-62, 2017
Reaction kinetics and mechanism between histidine and carbon dioxide
Amino acids are considered as potential solvents for carbon dioxide (CO2) capture. In this research, the reaction kinetics and reaction mechanism between histidine and CO2 were investigated. Results showed that histidine anion ions (His(-)) are the main species reacting with CO2 in basic conditions (pH > 9) with a reaction order of 1.18 +/- 0.08 across the temperature range of 298-313 K. The zwitterion mechanism was used to fit the kinetic data and it showed that both protonation and deprotonation reactions contributed to the overall reaction rate. Ionic strength was also shown to have a significant influence on the reaction kinetics when the histidine concentration is high (>= 0.2 M). The reaction rate between histidine and CO2 is slower than that of glycine and proline and slightly faster than that of taurine at low concentrations (<0.1 M). (C) 2016 Elsevier B.V. All rights reserved.