5-hydroxymethylfurfural and 1-butyl-3-methylimidazolium-chloride

A simple solid base catalyst, ammonium aluminum carbonate hydroxide (AACH), was prepared and its structure was characterized by many technologies, including XRD, FT-IR, SEM, BET and Elemental Analysis. The prepared catalyst was used to catalyze the conversion of glucose into 5-hydroxymethylfurfural (HMF) in ionic liquid 1-butyl-3-methylimidazolium chloride ([Bmim]

Topics: Carbonates; Catalysis; Dimethyl Sulfoxide; Fructose; Furaldehyde; Glucose; Hydroxides; Imidazoles; Ionic Liquids; Models, Chemical; Solvents; Temperature

A number of ionic liquids have been shown to be excellent solvents for lignocellulosic biomass processing, and some of these are particularly effective in the production of the versatile chemical building block 5-hydroxymethylfurfural (HMF). In this study, the production of HMF from the simple sugar glucose in ionic liquid media is discussed. Several aspects of the selective catalytic formation of HMF from glucose have been elucidated using metal halide salts in two distinct ionic liquids, 1-butyl-3-methylimidazolium chloride and 1-butyl-3-methylimidazolium hydrogen sulfate as well as mixtures of these, revealing key features for accelerating the desired reaction and suppressing byproduct formation. The choice of ionic liquid anion is revealed to be of particular importance, with low HMF yields in the case of hydrogen sulfate-based salts, which are reported to be effective for HMF production from fructose. The most successful system investigated in this study led to almost quantitative conversion of glucose to HMF (90% in only 30 minutes using 7 mol% catalyst loading at 120°C) in a system which is selective for the desired product, has low energy intensity and is environmentally benign.

Topics: Catalysis; Furaldehyde; Glucose; Imidazoles; Ionic Liquids; Kinetics; Substrate Specificity; Temperature

In recent years, cellulose has received increasing attention as a potential material for the production of biofuels and bio-based chemicals. In this study, a new process for the efficient conversion of cellulose into 5-hydroxymethylfurfural (HMF) was developed by the use of AlCl3 as the catalyst in DMSO-ionic liquid ([BMIM]Cl) mixtures. Various reaction parameters such as reaction time, reaction temperature, solvent and catalyst dosage were investigated in detail. A high HMF yield of 54.9% was obtained from cellulose at 150°C after 9h in a mixed solvent of DMSO-[BMIM]Cl (10 wt.%). More importantly, the catalytic system could be reused for several times despite of the slight loss of its catalytic activity.

Topics: Aluminum Chloride; Aluminum Compounds; Biofuels; Catalysis; Cellulose; Chlorides; Dimethyl Sulfoxide; Furaldehyde; Imidazoles; Ionic Liquids; Lewis Acids; Temperature

The efficient dehydration of fructose to 5-hydroxymethylfurfural (HMF) was developed in ionic liquids (ILs) with acidic ion-exchange resins as catalyst. By screening different resins and ILs respectively, it was found that the structure of resins and ILs had a prominent effect on the dehydration of fructose. In 1-butyl-3-methylimidazolium chloride ([Bmim]Cl), D001-cc resin showed a high activity. And then the effects of reaction temperatures, dosages of D001-cc, and different initial fructose loadings on the dehydration of fructose were studied in detail. The system of D001-cc resin and [Bmim]Cl exhibited a constant activity at 75°C for 20 min and a 86.2% yield of HMF was obtained after seven recycles. At 75°C for 20 min, a 93.0% yield of HMF from the dehydration of fructose was obtained.

Topics: Acids; Catalysis; Fructose; Furaldehyde; Imidazoles; Ion Exchange Resins; Ionic Liquids; Solvents; Temperature; Time Factors

In this study, synthesis of HMF from carbohydrates was carried out in ionic liquids 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) catalyzed by ScCl3 under microwave irradiation. Under the optimal reaction conditions, HMF was obtained in a high yield of 73.4% in 2 mins with the microwave power at 400 W. Compared with the conventional oil-bath heating manner, the use of microwave irradiation not only reduced reaction times from hours to minutes, but also improved HMF yield. This catalytic system could be reused several times without losing its catalytic activity. This efficient catalytic system will generate a promising application strategy for biomass transformation.

Topics: Carbohydrates; Catalysis; Chlorides; Furaldehyde; Imidazoles; Ionic Liquids; Microwaves; Molecular Structure; Scandium

Micro/mesoporous chromium, aluminium-containing silicates of the type TUD-1 (Al-TUD-1, Cr-TUD-1, CrAl-TUD-1) and zeolite BEA, Cr-BEA, and related composites BEA/TUD-1 and Cr-BEA/TUD-1, were prepared, characterised, and tested as solid acids coupled with the ionic liquid (IL) 1-butyl-3-methylimidazolium chloride ([bmim]Cl) as solvent, in the transformation of D-glucose into 5-(hydroxymethyl)-2-furaldehyde (Hmf), at 120 °C. The chromium-containing catalytic systems lead to considerably higher Hmf yields in comparison to the related systems without chromium. The IL is a favourable solvent for this target reaction (in terms of Hmf yields reached) compared to water or dimethylsulfoxide. A detailed study on the stabilities of the nanoporous solid acids in the IL medium is presented.

Topics: Aluminum Silicates; Catalysis; Chromium; Furaldehyde; Glucose; Imidazoles; Ionic Liquids; Solvents

Production of 5-hydroxymethylfurfural (HMF) from cellulose catalyzed by solid acids and metal chlorides was studied in the 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) under microwave irradiation. Among the applied catalysts, the use of CrCl(3)/LiCl resulted in the highest yield of HMF. The effects of catalyst dosage (mole ratio of catalyst to glucose units in the feedstock) and reaction temperature on HMF yields were investigated to obtain optimal process conditions. With the 1:1 mol ratio of catalyst to glucose unit, the HMF yield reached 62.3% at 160°C for 10 min. Untreated wheat straw was also investigated as feedstock to produce HMF for the practical use of raw biomass, in which the HMF yield was comparable to that from pure cellulose. After the extraction of HMF, [BMIM]Cl and CrCl(3)/LiCl could be reused and exhibited no activity loss after three successive runs.

Topics: Biofuels; Biomass; Catalysis; Furaldehyde; Glucose; Hydrolysis; Imidazoles; Lignin; Microwaves; Plant Components, Aerial; Temperature; Triticum

Conversion of fructose and glucose into 5-hydroxymethylfurfural (HMF) was investigated in various imidazolium ionic liquids, including 1-butyl-3-methylimidazolium chloride (BmimCl), 1-hexyl-3-methylimidazolium chloride (HmimCl), 1-octyl-3-methylimidazolium chloride (OmimCl), 1-benzyl-3-methylimidazolium chloride (BemimCl), 1-Butyl-2,3-dimethylimidazolium chloride (BdmimCl), and 1-butyl-3-methylimidazolium p-toluenesulfonate (BmimPS). The acidic C-2 hydrogen of imidazolium cations was shown to play a major role in the dehydration of fructose in the absence of a catalyst, such as sulfuric acid or CrCl(3). Both the alkyl groups of imidazolium cations and the type of anions affected the reactivity of the carbohydrates. Although, except BmimCl and BemimCl, other four ionic liquids could only achieve not more than 25% HMF yields without an additional catalyst, 60-80% HMF yields were achieved in HmimCl, BdmimCl, and BmimPS in the presence of sulfuric acid or CrCl(3) in sufficient quantities.

Topics: Borates; Catalysis; Chlorides; Chromium Compounds; Fructose; Furaldehyde; Glucose; Imidazoles; Ionic Liquids; Sulfuric Acids

An investigation was carried out into the hydrolysis of cellulose dissolved in 1-ethyl-3-methylimidazolium chloride ([Emim][Cl]) and 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]) catalyzed by mineral acids. Glucose, cellobiose, and 5-hydroxymethylfurfural (5-HMF) were observed as the primary reaction products. The initial rate of glucose formation was determined to be of first order in the concentrations of dissolved glucan and protons and of zero order in the concentration of water. The absence of a dependence on water concentration suggests that cleavage of the β-1,4-glycosidic linkages near chain ends is irreversible. The apparent activation energy for glucose formation is 96 kJ mol(-1). The absence of oligosaccharides longer than cellobiose suggests that cleavage of interior glycosidic bonds is reversible due to the slow diffusional separation of cleaved chains in the highly viscous glucan/ionic liquid solution. Progressive addition of water during the course of glucan hydrolysis inhibited the rate of glucose dehydration to 5-HMF and the formation of humins. The inhibition of glucose dehydration is attributed to stronger interaction of protons with water than the 2-OH atom of the pyranose ring of glucose, the critical step in the proposed mechanism for the formation of 5-HMF. The reduction in humin formation associated with water addition is ascribed to the lowered concentration of 5-HMF, since the formation of humins is suggested to proceed through the condensation polymerization of 5-HMF with glucose.

Topics: Cellobiose; Cellulose; Furaldehyde; Glucose; Imidazoles; Ionic Liquids; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

A new compound was detected during the production of 5-hydroxymethylfurfural (HMF) from glucose and cellulose in the ionic liquid 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) at high temperatures. Further experiments found that it was derived from the reaction of HMF with [Bmim]Cl. The structure of new compound was established as 1-butyl-2-(5'-methyl-2'-furoyl)imidazole (BMI) based on nuclear magnetic resonance and mass spectrometry analysis, and a possible mechanism for its formation was proposed. Reactions of HMF with other imidazolium-based ionic liquids were performed to check the formation of BMI. Our results provided new insights in terms of side reactions between HMF and imidazolium-based ionic liquids, which should be valuable for designing better processes for the production of furans using biomass and related materials.

Topics: Catalysis; Cellulose; Furaldehyde; Glucose; Hot Temperature; Imidazoles; Ionic Liquids; Magnetic Resonance Spectroscopy; Mass Spectrometry; Molecular Structure