On the interference of urea with CO/CO chemistry of cellulose model solutions in NaOH(aq).

The CO/CO chemistry of the cellulose/NaOH(aq) solutions has been recently reported to comprise a CO incorporation through formation of a transient cellulose carbonate intermediate along with cellulose - CO interactions. This work explores on molecular interactions arising when this chemistry is brought together with urea, the most common stabiliser of these solutions. H, C and steady-state heteronuclear Overhauser effect NMR studies on the cellulose analogues (methyl-β-glucopyranoside (β-MeO-Glcp) and microcrystalline cellulose), combined with pH and ATR-FTIR measurements, reveal concurrent interactions of urea with both CO and CO- leading to increased uptake of CO and a buffering effect. Yet, regardless of the presence of urea, the route of conversion from CO to CO, whether going through reaction with the carbohydrate alkoxides or OH, is likely to determine the chemical environment of the formed CO. These findings shed a new light on rather overlooked, albeit prominent, interactions in these solutions with the readily absorbed air CO, essential for further development and implementation, whether towards regenerated and modified cellulose or CO-capturing concepts.