Liquid speciation study in amine amino acid salts for CO2 absorbent with 13C-NMR.

Abstract: Qualitative ¹³C-NMR experiments were performed at 298 K and for different loadings to investigate the liquid speciation in amino acid neutralized by both strong inorganic and weak organic bases. The two different systems, potassiumsarcosinate(KSAR) and sarcosine blended with equinormal quantities of 3-(methylamino)propylamine (MAPA-SAR) were studied. In presence of CO₂, the spectra of the MAPA-SAR system showed more species than that of the K-SAR system due to the presence of carbamates from the primary, secondary and amino acid amine groups even at very low loadings. This means that complete neutralization of sarcosine with MAPA does not occur since carbamates of the primary and secondary amine group of MAPA were formed in the system. In order to quantify the percentage of carbamate formed on the amine group of sarcosine compared to carbamates formed on MAPA, a quantitative ¹³C-NMR experiment is needed as a future work. [Copyright &y& Elsevier]