Chitin-acetate/DMSO as a supramolecular green CO2-phile

Abstract

The supramolecular chemisorption of CO₂ by the oligomeric chitin-acetate (CA) in DMSO as a green solvent offers a novel eco-friendly approach for CO₂ capture. Since the amino groups in the sorbent material are blocked either by protonation or acetylation, the multi-armed hydroxyl based oligosaccharide captures CO₂ through the formation of an organic carbonate species as confirmed by ¹³C NMR, in situ ATR-FTIR spectroscopy and conductivity. DFT calculations verified the formation of the CA-CO₂ adduct, in which the organic carbonate group is stabilized through supramolecular ionic interaction and hydrogen bonding with the neighboring ammonium ion and hydroxyl functional group along the oligomer backbone. The use of other polar aprotic solvents (N,N-dimethylformamide (DMF), acetonitrile, and acetone) was not successful due to solubility issues.