Thermal degradation comparison of amino acid salts, alkanolamines and diamines in CO₂ capture

In the selection of candidates for post-combustion CO₂ absorption, solvent degradation has become a general concern due to the significant impact on operational cost and the intention to use thermal compression from high temperature stripping to minimize the overall process energy. In this research, structural analogs of amino acid salts, alkanolamines and diamines were thermally degraded in order to explore their thermal stability from a structural standpoint. Functional groups, amine orders and steric effect were investigated for their impact on amine thermal degradation. Primary amines with chain structures showed a thermal stability trend as diamine > alkanolamine > amino acid salt. For alknolamine and diamine structural isomers, the primary amines are more stable than the secondary amines. Steric hindrance around the amine group was shown to play a positive role in protecting amines against thermal degradation.