Experimental study on carbamate formation in the AMP-CO2-H2O system at different temperatures

Carbamate formation in the 30 wt% of 2-amino-2-methyl-1-propanol (AMP) system at different CO2 loadings and temperatures was studied via nuclear magnetic resonance (NMR) spectroscopy. The results indicate that the main species in this system are AMP/AMPH(+), AMPCO(2)(-) and HCO3-/CO32. The carbamate was also observed at low loadings and the apparent carbamate stability constant was estimated based on the experimental concentrations of the species from NMR analysis. Carbamate formation was found to have weak temperature dependence in he range rested (25-45 degrees C). To distinguish within the AMP/AMPH(+) and HCO3-/CO32 pairs, the amine protonation constant, the dissociation constant of carbonic acid from literature, and pH measurements for different ionic strengths were all employed. All the data were correlated with ionic strength and temperature. The accuracy of the carbamate stability constant determined from the concentration measurements will depend on pK(a), ionic strength (I) used to calculate the speciation and on the uncertainty in the species concentration determinations horn NMR, particularly for the carbamate species at low CO2 loadings and high temperature. (C) 2014 Elsevier Ltd. All rights reserved