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]2H4P2Mo18O62 [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]2H4P2Mo18O62 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.

The Novel Ionic Liquid and Its Related Self‐Assembly in the Areas of Energy Storage and Conversion

“…POM‐ILs have shown great potential applications in energy storage and conversion in recent years. [ 145–147 ] For example, Cruz et al reported four POM‐ILs based on phosphomolybdate anion (PMo 12 O 40 3− ). [ 148 ] In this work, the POM‐ILs were adsorbed to the TiO 2 film and were used as photosensitizers.…”

“…POM-ILs have shown great potential applications in energy storage and conversion in recent years. [145][146][147] ). [148] In this work, the POM-ILs were adsorbed to the TiO 2 film and were used as photosensitizers.…”

Developing Dawson-Type Polyoxometalates Used as Highly Efficient Catalysts for Lignocellulose Transformation

“…Up to the present, many efforts have been made to study the acidity and oxidation–reduction property of Keggin structural POMs, − whereas less attention had been paid to the properties and catalytic performance of POMs with Dawson structure . In our previous study on biomass conversion, the acidity and redox effects of H 6 P 2 Mo 18 O 62 (H 6 P 2 Mo 18 ) on the full conversion of lignocellulose were evaluated through the lignin-first concept . It was found that the Dawson-type POMs containing Mo addendum were more suitable for depolymerization of lignocellulose due to their suitable acidic and redox properties.…”

Hydroxyapatite‐Supported Polyoxometalates for the Highly Selective Aerobic Oxidation of 5‐Hydroxymethylfurfural or Glucose to 2,5‐Diformylfuran under Atmospheric Pressure

“…[6] One solidifying is to partially exchange protons of molybdovanadophosphate with Cs + , Ag + , Lewis metal ions such as Sn 4 + , Zn 2 + , or anionic organo-groups of anion, ionic liquid, and quaternary ammonium. [7][8][9] This method demonstrated a comparatively convenient way to fabricate and tune the acidity for POMs. However, some Brønsted acidic sites were decreased due to the loss of protons.…”

“…Many efforts had been made to solidify their structures into heterogeneous forms, which were exhaustively reviewed by Ishii and co‐workers [6] . One solidifying is to partially exchange protons of molybdovanadophosphate with Cs + , Ag + , Lewis metal ions such as Sn 4+ , Zn 2+ , or anionic organo‐groups of anion, ionic liquid, and quaternary ammonium [7–9] . This method demonstrated a comparatively convenient way to fabricate and tune the acidity for POMs.…”