Efficient Catalytic Conversion of Fructose into 5‐Hydroxymethylfurfural in Ionic Liquids at Room Temperature

Abstract

One of the main challenges for establishing a society that uses biomass-derived carbohydrate chemistry will be the development of effective chemical transformations that are rapid and that can be performed at room temperature. Herein, we report a method for transforming fructose into 5-hydroxymethylfurfural (5-HMF) that is quantitative and operates at room temperature. The preparation of 5-HMF, which is a versatile, key renewable platform molecule from biomass-derived carbohydrates, is regarded as an essential transformation needed in carbohydrate chemistry. [1][2][3] The formation of 5-HMF by the acid-catalyzed dehydration of fructose has been demonstrated in water, [4] traditional organic solvents, [5,6] multiphase systems, [1][2][3] and ionic liquids (ILs). [7][8][9] Dumesic and co-workers studied acid-catalyzed fructose dehydration in a two-phase reactor system at 180 8C, [1] and achieved a maximum 5-HMF selectivity of 85 % with 89 % fructose conversion.[3] Binder et al. developed a process that converted fructose to 5-HMF in N,N-dimethylacetamide in the presence of KI and H 2 SO 4 at 100 8C for 5 h reaction time, and achieved a 5-HMF yield of 92 %.[6] These reports indicate that the effective conversion of fructose into 5-HMF in water, organic solvents, and multiphase systems requires high reaction temperatures of 100 to 300 8C. Ionic liquids have been studied for the transformation of fructose and it has been found that the reaction temperature can be lowered to temperatures ranging from 80 to 140 8C for reaction times on the order of hours. Zhao et al. achieved a 5-HMF yield of 83 % in an ionic liquid solvent (1-ethyl-3-methylimidazolium chloride, [EMIM][Cl]) with CrCl 2 as catalyst at a temperature of 80 8C for a reaction time of 3 h.[9] Yong et al. studied the production of 5-HMF from fructose in 1-butyl-3-methyl imidazolium chloride ([BMIM][Cl]) using CrCl 2 as catalyst, and 5-HMF yields of 96 % were achieved at 100 8C in 6 h reaction time. [7] Up until now, all of these processes have reported that temperatures above 80 8C were necessary for the transformation reactions, with some of the chief reasons being those related to the melting point of the ionic liquid or to the high viscosity of the reaction mixture.Performing reactions that at ambient conditions can be considered as one of the key goals among the 12 Principles of Green Chemistry.[10] The method proposed in this work uses safe catalytic methods and avoids harsh solvents. We selected 1-butyl-3-methyl imidazolium chloride ([BMIM][Cl]) as solvent and Amberlyst 15 strong acidic ion-exchange resin as the catalyst for the conversion of fructose into 5-HMF. [BMIM][Cl] is commonly used as an IL solvent or precursor to other ILs, [11] and has a melting point of about 70 8C. Reactions at 25 8C might not seem possible, but after predissolving the fructose into the IL and subsequently adding a small amount of any one of a number of common solvents, the reaction proceeded smoothly and efficiently at room temperature. In a typical experiment, 0.05 g of fr...

Hydrolysis of chitosan to yield levulinic acid and 5-hydroxymethylfurfural in water under microwave irradiation

“…Thus indicating that this process is catalyzed more effectively by a suitable Lewis acid rather than a Brønsted acid. The largest amounts of LA (23.9 wt%) and 5-HMF (3.95 wt%) produced in this set of reactions came from those using SnCl 4 ·5H 2 O (15) and BiCl 3 (12), respectively.…”

Kinetics of furfural production by dehydration of xylose in a biphasic reactor with microwave heating

“…27, 28 The application of ionic liquids in carbohydrates (lignocellulosic biomass) chemistry is relatively new and further studies combining these two fields are presented by Zakrzewska et al 29 Additionally, Qi et al also reported promising results when they studied the production of HMF from glucose and fructose catalyzed by TiO 2 and ZrO 2 under microwave irradiation.…”

Ionic Liquids in Catalytic Biomass Transformation

“…[Cl] with different co-solvents such as DMSO, acetone, methanol, ethanol, ethyl acetate and supercritical carbon dioxide [32]. Fructose was first dissolved in ILs at 80C and added Amberlyst-15, a strong acidic ion-exchange resin catalyst, and co-solvent was added to give a gel-like mixture after cooling.…”

“…Fructose was first dissolved in ILs at 80C and added Amberlyst-15, a strong acidic ion-exchange resin catalyst, and co-solvent was added to give a gel-like mixture after cooling. It was demonstrated that the reaction could proceed at an ambient temperature of 25C with yields of 78% -82% for 5-HMF [32].…”