Carbanion-based ionic liquids are proposed and utilized as the key
components for the construction of five super-nucleophilic deep eutectic
solvents (SNDESs) in the paper. The super-nucleophilic nature of
carbanion-based ILs is found to enable the capture of
CO with large absorption capacity. However, the
absorption is very slow in the IL due to high viscosity. The synergy of
carbanion siting and hydrogen bonding is found to enable high and fast
absorption of CO in
[N][CH(CN)]-ethylimidazole
(Eim), and a synergistic absorption mechanism is proposed and validated
from spectroscopic analyses and quantum calculations. The enthalpy
change of CO absorption in
[N][CH(CN)]-Eim is
calculated to be -39.6 kJ/mol according to the thermodynamic model, and
the moderate value implies that both absorption and desorption of
CO in the DES are favored and well balanced. The
synergism of carbanion and hydrogen bond mediated by SNDESs provides a
novel insight into the efficient CO capture.