Natural deep eutectic solvents efficient catalytic conversion of cellulose to total reducing sugars (TRS)

Abstract Lignocellulosic biomass contains about 45% cellulose. The total reducing sugars (TRS) obtained from lignocellulosic materials is beneficial to the sustainable development. Natural deep eutectic solvents (NADESs) provide an attractive alternative for the “green” conversion of cellulose. In this work, series of amino acids based NADESs with FeCl3.6H2O as ligands catalyst were synthesized and characterized by in situ IR, FT-IR, 1H NMR and TG-DTA. NADESs showed great thermal stability. The efficient hydrolysis performance of cellulose in NADESs was investigated under mild conditions. The influencing factors such as the type of NADESs, reaction temperature, reaction time, and FeCl3.6H2O addition on the TRS yield were studied. The optimized process conditions for hydrolyzing cellulose in L-Proline/ Ethylene glycol/FeCl3.6H2O were molar ratio 1: 2: 1, reaction time 120 min and temperature 120 °C. The yield of total reducing sugar was 66.7%. The conversion mechanism was also investigated.