Metal-Catalyzed Degradation of Cellulose in Ionic Liquid Media

Abstract

Biomass conversion to 5-hydroxymethylfurfural (HMF) has been widely investigated as a sustainable alternative to petroleum-based feedstock, since it can be efficiently converted to fuel, plastic, polyester, and other industrial chemicals. In this report, the degradation of commercial cellulose, the isomerization of glucose to fructose, and the conversion of glucose to HMF in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl]) using metal catalysts (CrCl3, ZnCl2, MgCl2) as well as tungsten and molybdenum oxide-based polyoxometalates (POM) were investigated. Tungsten and molybdenum oxide-based POMs in ionic liquids (IL) were able to degrade cellulose to majority glucose and epimerize glucose to mannose (in the case of the molybdenum oxide-based POM). A certain amount of glucose was also converted to HMF. The tungsten oxide-based POM in IL showed good activity for cellulose degradation but the overall products yield remained 28.6% lower than those obtained using CrCl3 as a catalyst. Lowering the cellulose loading did not significantly influence the results and the addition of water to the reaction medium decreased the product yields remarkably.

Supported MoOx and WOx Solid Acids for Biomass Valorization: Interplay of Coordination Chemistry, Acidity, and Catalysis

“…Compared to water, which generally causes the leaching of the active sites, ionic liquid (1-butyl-3-methylimidazolium chloride) as a solvent effectively converts cellulose to glucose, fructose, and HMF over WO x -and MoO x -based polyoxometalates. 218 The reaction follows cellulose conversion to glucose, epimerization of glucose to mannose, and then dehydration to HMF with an overall product yield of 28.6%. The results were not influenced by decreasing the cellulose loading.…”

“…The solid catalysts with strong acid sites showed good reusability for seven cycles without much loss in catalytic activity. Compared to water, which generally causes the leaching of the active sites, ionic liquid (1-butyl-3-methylimidazolium chloride) as a solvent effectively converts cellulose to glucose, fructose, and HMF over WO x - and MoO x -based polyoxometalates . The reaction follows cellulose conversion to glucose, epimerization of glucose to mannose, and then dehydration to HMF with an overall product yield of 28.6%.…”

Recent Trends in Elaboration, Processing, and Derivatization of Cellulosic Materials Using Ionic Liquids

“…The ability of the polyoxometalates to convert glucose to 5-hydroxymethylfurfural remained 28.6% lower compared to the yield obtained with CrCl 3 . 106 In another work, the one-step conversion of cellulose to HMF (5hydroxymethylfurfural), an important renewable biofuel precursor and a useful building block, has been achieved in the presence of metal chlorides (CrCl 3 , CuCl 2 , SnCl 4 , WCl 6 ) in [C 4 mim]Cl (Scheme 3). 107 These trials highlight the ability of ionic liquids to dissolve high molecular weight cellulose and to promote controlled cellulose degradation reactions.…”

“…For example, Aid et al showed that tungsten and molybdenum oxide-based polyoxometalates are able to decompose cellulose to carbohydrates such as glucose and mannose and a certain amount of glucose was also converted to 5-hydroxymethylfurfural. The ability of the polyoxometalates to convert glucose to 5-hydroxymethylfurfural remained 28.6% lower compared to the yield obtained with CrCl 3 . In another work, the one-step conversion of cellulose to HMF (5-hydroxymethylfurfural), an important renewable biofuel precursor and a useful building block, has been achieved in the presence of metal chlorides (CrCl 3 , CuCl 2 , SnCl 4 , WCl 6 ) in [C 4 mim]Cl (Scheme ).…”

Energy‐efficient Electrochemical Hydrogen Production Combined with Biomass Oxidation Using Polyoxometalate and Metal Salts

“…In addition, POMs have strong tolerance to impurities, and the reduced POMs can be re‐oxidized and regenerated on simple graphite electrodes, with low energy consumption and huge economic benefits [19,20] . However, the solid biomass with complex networks of polymeric components, especially the hydrogen bond network of cellulose, remained as the highly challenging bottle neck to hydrolytic and oxidative degradation, thus limiting the overall electrochemical reaction rate [21] …”