Protic ionic liquid as excellent shuttle of MDEA for fast capture of CO2

A cheap protic ionic liquid (PIL), 3‐(Dimethylamino)‐1‐propylamine acetate (abbreviated as [DMAPAH][Ac]), is investigated in this work as the activator of N‐methyldiethanolamine (MDEA) for fast capture of CO₂. The PIL‐activated MDEA solutions show excellent performance in absorption rate and capacity (≥2.5 mol·kg^?1). A novel absorption mechanism is proposed to account for the phenomenon, where the shuttling role of the PIL is described in detail. Additionally, the enthalpy change ΔH_SOL (?45 to ?52 kJ·mol^?1), the turnover number of the PIL and the regeneration efficiency (>92%) are also measured. All these data show that the PIL‐mediated MDEA solutions may be used as a kind of promising absorbents for fast capture of CO₂. © 2017 American Institute of Chemical Engineers AIChE J, 63: 209–219, 2018