Structure‐Function Relationships in Fructose Dehydration to 5‐Hydroxymethylfurfural under Mild Conditions by Porous Ionic Crystals Constructed with Analogous Building Blocks

Abstract

5‐Hydroxymethylfurfural (HMF) is an important bio‐based chemical, which has been recognized as a key platform chemical for furan‐based polymers, biomass‐derived fuels, fine chemicals, and pharmaceuticals. Catalytic conversion of fructose into HMF is an important reaction, and the development of an efficient heterogeneous catalysts with high selectivity towards HMF is highly desired. In this study, several porous ionic crystals with a Keggin‐type polyoxometalate [PW12O40]3− and a macrocation [Cr3O(OOCCH2CN)6(H2O)3]+ as building blocks are synthesized, and the structures are solved by single crystal X‐ray diffraction analysis. The catalytic activities are basically dependent on the porosity, and the compound with a mesopore (aperture: 3 nm×2 nm) showed the highest HMF yield (30 % at 353 K in methanol/toluene solvent).

Rapid, High‐Yield Fructose Dehydration to 5‐Hydroxymethylfurfural in Mixtures of Water and the Noncoordinating Ionic Liquid [bmim][OTf]

“…Of the 94 productso btained from these sugars, 25 were selected as involving feasible technologiest hat are suitablef or large-scale prototype testing in ap ilot plant. [11][12][13] Other research has focused on optimizingh eterogeneous catalysts for dehydration reactions involving both metal catalysts [14][15][16][17][18][19][20] and supported ionic liquids. [3] The main route to form HMF is by the dehydration of sugars, [4] and important resultsh ave been achieved for HMF production using ionic liquids.…”

“…[10] Deep eutectic solvents andw ater have also been investigated for the dehydration of fructose into HMF but improvedy ields are still needed. [11][12][13] Other research has focused on optimizingh eterogeneous catalysts for dehydration reactions involving both metal catalysts [14][15][16][17][18][19][20] and supported ionic liquids. [21,22] In particular, ionic liquidsw ith halide counteranions have provenv ery efficient for the production of HMF from fructose, glucose,a nd cellulose with both Brønsted and Lewis acid catalysts.…”

Structure-function Relationships of Porous Ionic Crystals (PICs) Based on Polyoxometalate Anions and Oxo-centered Trinuclear Metal Carboxylates as Counter Cations

“…The meso-PIC catalyzed fructose dehydration to HMF without any apparent byproducts (typical byproducts are levulinic acid and formic acid) under mild conditions in a methanol/toluene solvent (HMF yield 30% at 353 K and 30 min). 59 In contrast, PIC with analogous ionic components and micropores showed much lower catalytic activities under the same reaction conditions (HMF yield <10%). These results indicate that the mesoporous structure is important to achieve a high catalytic activity in fructose dehydration reaction.…”

“…14 Polyoxometalates (POMs) are nano-sized metaloxide anion clusters (macroanions) with unique redox, catalytic, magnetic, and luminescent properties and have been researched in broad fields of science. 59 Recently, incorporation of POMs into the nano-sized cavities of MOFs have been successfully reported, and these POM-MOF composites show cooperative effects of POMs and MOFs in adsorption of cationic dyes, photochemical and electrochemical water splitting, CO 2 fixation, and so on. 1012 In contrast, we have been working on porous ionic crystals (PICs), which are crystalline composites of POMs with molecular cations (macrocations) such as the oxo-centered trinuclear metal carboxylates with a general formula of [M 3 O(OOCR) 6 (L) 3 ] + .…”

Meet the Women of Catalysis

“…She has received several prizes including Young Scientists’ Prize for the Commendation for Science and Technology from the Minister of Education, Culture, Sports, Science and Technology (MEXT). Her research focuses on design and synthesis of hierarchically‐assembled porous ionic crystals based on polyoxometalates, with unique ion/gas adsorption, diffusion, and catalytic properties for energy storage and conversion systems …”