Unveiling solvent encapsulation‐driven kinetic inversion in CO 2 absorption by water‐lean amine solvents

Abstract Amine‐based water‐lean solvents serve as energy‐efficient absorbents for carbon dioxide (CO 2 ) capture but face paradoxical kinetic challenges, where the mixed solvents inconsistently accelerate or decelerate reaction rates across amine classes. By integrating stopped‐flow kinetics, molecular dynamics simulations, and electrostatic potential analysis, we elucidate water modulates CO 2 absorption in mixed absorbents systems via amine‐specific solvent encapsulation effect for the first time. For primary amines (e.g., monoethanolamine, MEA), water preferentially hydrates nucleophilic nitrogen atoms, forming steric barriers that impede CO 2 access and suppress kinetics with increasing hydration. Conversely, secondary amines (e.g., methylaminoethanol, MAE) exhibit oxygen‐directed hydration, which weakens nitrogen solvation and enhances electrostatic CO 2 ‐amine interactions, accelerating kinetics. A zwitterion‐based kinetic model quantifies these solvent‐induced activation energy shifts, revealing a universal mechanism validated across diverse solvent systems. This work establishes molecular design principles for tailoring water‐lean absorbents, bridging the critical gap between solvent engineering and reaction pathways to advance energy‐efficient carbon capture technologies.