Equilibria of MEA, DEA and AMP with Bicarbonate and Carbamate: a Raman Study.

Abstract

Species distribution analysis in carbonated alkanolamine solution is import in order to estimate accurate thermodynamic properties. The applicability of Raman spectroscopy as an analytical tool for speciation of carbonated aqueous alkanolamine systems was studied. Alkanolamine solutions loaded with HCO3– were measured using ClO3− as internal standard. The same solutions were measured with 13C-NMR spectroscopy. The molar scattering intensity factors for HCO3, CO3 and MEA- and DEA-carbamate were found to be 0.1973, 0.2901, 0.0632 and 0.0400 respectively. Characteristic bands of these species were identified at 1017, 1067, and 1162 cm−1. A lower detection limit for HCO3– anions in MEA and DEA solution was observed. Bands for potential quantification of free- and protonated alkanolamine are identified in the region of 2800 - 3800 cm−1.