Conversion of Glucose to 5-Hydroxymethylfurfural in Deep Eutectic Solvent of Choline Chloride–Chromium Chloride

Abstract

5-Hydroxymethylfurfural (HMF) is a crucial biobased compound for synthesizing chemicals and biofuels, but the direct conversion of glucose to HMF suffers low yield and purification problems. In this paper, a cheap and efficient deep eutectic solvent (DES) of choline chloride−chromium chloride (ChCl−CrCl 3 • 6H 2 O) was developed to convert glucose and other carbohydrates to HMF. High HMF yields of 70.2, 78.6, 72.6, and 71.7% were achieved from glucose, fructose, high fructose corn syrup, and sucrose, respectively. The DES ChCl−CrCl 3 •6H 2 O could be reused nine times without a significant loss of catalytic activity. In addition, a method was developed to regenerate humins-polluted DES. Combined with ultraviolet and visible spectrum data and density functional theory calculation, [Cr(H 2 O) 2 Cl 3 Ch] + was identified as the active species in DES ChCl−CrCl 3 •6H 2 O. This paper proposed a new effective system to convert carbohydrates to HMF. The discovery of active species provides a base for future studies on dehydration mechanisms.

High-yield synthesis of HMF from glucose and fructose by selective catalysis with water-tolerant rare earth metal triflates assisted by choline chloride

“…The purity of the product was also confirmed by 1 H NMR spectroscopy in accordance with the spectra previously reported. 48…”

“…46,47 Choline chloride-based DES together with metal halide have been proven to be efficient methods to produce HMF from carbohydrates, but the main drawbacks are the need for large amounts of solvents to extract the product from the ionic phase and the toxicity of Lewis acid metals, for example, the use of chromium. 48,49 Rare earth metal halides and triflate have proved to be excellent Lewis acids as the catalytic system for HMF synthesis from glucose and fructose but the use of harmful solvents like N,N ′ -dimethylacetamide (DMA), and DMSO was necessary to reach efficient yields. 50,51 In continuity with respect to the well-documented catalytic activity and water-tolerability of triflate lanthanides, [52][53][54] in this work, we proved the stability and the exceptional catalytic activity of rare-earth metal triflates to produce HMF through isomerization-dehydration of carbohydrates, with the participation of choline chloride, an abundant, cheap and biodegradable substrate that allows Fisher-type glycosylation on fructose before the dehydration steps.…”

Deep Eutectic Solvents as à-la-Carte Medium for Transition-Metal-Catalyzed Organic Processes

“…In addition, the DES could be reused up to five times without losing its activity with an O 2 treatment after each cycle ( Figure 1 , Table 1 , entry 1) [ 4 ]. Similarly, 5-hydroxymethylfurfural (HMF) has been obtained in high yields by treatment of glucose at 130 °C with the eutectic ChCl:CrCl 3 .6H 2 O in a biphasic mixture with solvents, such as EtOAc, through different dehydration processes [ 5 ].…”

Experimental study combined with density functional theory and molecular dynamics simulation on the mechanism of glucose alcoholysis reaction

“…At present, various acidic catalysts have been investigated in the glucose alcoholysis reactions, including zeolites, 4 metal salts, 5 ion exchange resins, 6 heteropolyacids, 7 and inorganic acids 8 . For example, Bounoukta et al prepared a bifunctional carbon‐based solid acid by loading Brønsted and Lewis acid sites on activated carbon for glucose conversion in MIBK/H 2 O system and obtained 57% HMF yield at 180°C 9 .…”

“…At present, various acidic catalysts have been investigated in the glucose alcoholysis reactions, including zeolites, 4 metal salts, 5 ion exchange resins, 6 heteropolyacids, 7 and inorganic acids. 8 For example, Bounoukta et al prepared a bifunctional carbon-based solid acid by loading Brønsted and Lewis acid sites on activated carbon for glucose conversion in MIBK/H 2 O system and obtained 57% HMF yield at 180 C. 9 Chang et al used a mixture of ultra-low concentration sulfuric acid and H-USY to catalyze glucose conversion into EL, and the EL yield reached 51.47% at 180 C. 10 Zuo used CrCl 3modified Amberlyst-15 to catalyze glucose in deep eutectic solvents (DESs) system and obtained a 46.7% yield of EMF.…”