Full Utilization of Lignocellulose with Ionic Liquid Polyoxometalates in a One‐Pot Three‐Step Conversion

Abstract The lignin‐first concept is a new innovation for full utilization of lignocellulose into value‐added chemicals. Ionic liquid (IL) polyoxometalates [MIMPS] 2 H 4 P 2 Mo 18 O 62 [MIMPS=1‐(3‐sulfonic group) propyl‐3‐methyl imidazolium] are reported to be active in the cleavage of β‐O‐4, α‐O‐4, and 4‐O‐5 bonds in three kinds of lignin models and also efficient for converting native lignocellulose. The three components in soft or hard lignocellulose were depolymerized in a one‐pot three‐step treatment. For soft lignocellulose (pine), lignin was first decomposed into guaiacol and phenol with yields of 15.3 and 12.9 % at 98.6 % delignification efficiency at 130 °C for 14 h. Meanwhile, hemicellulose and cellulose were intact during the delignifying process and were subsequently hydrolyzed to 3.5 % xylose at 100 % hemicellulose conversion efficiency at 150 °C for 14 h and 36.4 % glucose at 100 % cellulose conversion efficiency at 170 °C for 12 h, respectively. For hard lignocellulose (poplar), the yields of guaiacol and phenol were 10.1 and 8.7 % at 91.9 % delignification efficiency at 130 °C for 14 h, whereas 12.9 % xylose at 90.4 % hemicellulose conversion efficiency at 150 °C for 12 h and 32.9 % glucose at 100 % cellulose conversion efficiency at 170 °C for 12 h were obtained. [MIMPS] 2 H 4 P 2 Mo 18 O 62 achieved the full utilization of lignocellulose with total conversion in the lignin‐first strategy and also showed the easy separation as a result of temperature‐reversibility with ten recycling runs.