LAUSR

In the current work, a green and recyclable FeCl3-catalyzed deep eutectic solvent system (F-DES) was invented to fabricate cellulose nanocrystals (CNCs) with a high yield and excellent thermal stability. It was found that the optimum composition of the FeCl3-catalyzed deep eutectic solvent was composed of oxalic acid dihydrate (Oxd), choline chloride (ChCl), and FeCl3·6H2O in a mass ratio of 4:1:0.2 (corresponding to the molar ratio of 4.43:1:0.1). Results showed that CNCs with a diameter range of 5–20 nm and length of 50–300 nm could be isolated from bleached eucalyptus kraft pulp (BEKP) at a high yield (over 90% based on the cellulose content in BEKP) by a one-step F-DES treatment under mild conditions (80 °C, 6 h). The resultant CNCs showed a much higher thermal stability (onset thermal degradation temperature was over 310 °C) than the traditional sulfuric acid hydrolyzed ones and also exhibited superior dispersion stability in water due to the introduction of carboxyl groups on the surface of CNCs by ...