Combined insights from experiment and molecular simulation on thermal stability of amine blends for <scp> CO ₂ </scp> capture

Abstract Formulating superior absorbent by amine blending is a vital strategy for CO 2 capture. However, the blend of different amines may affect their chemical stabilities and hinder the long‐term operation of CO 2 capture system. This work studied the stability of amine blends composed of 1‐amino‐2‐propanol (1AP) and various tertiary amines, aiming to reveal their influence on thermal degradation. The addition of 1AP reduced the thermal stability of tertiary amines, as 1AP accepts alkyl groups from the protonated tertiary amines. Density functional theory (DFT) was used to verify the proposed thermal degradation mechanism of blended amines. The computational results suggest that the increase in blended amine loss was closely related to the decrease of the free energy barriers for the alkylation reactions between tertiary amine and 1AP. In addition, the thermal stability of blended amines associated with amine protonation degree in solution based on the 13 C NMR analysis.