Skip to main content
NCBI home page
ACS Omega logoLink to ACS Omega
. 2021 Mar 5;6(10):6798–6809. doi: 10.1021/acsomega.0c05857

Sulfonic Derivatives as Recyclable Acid Catalysts in the Dehydration of Fructose to 5-Hydroxymethylfurfural in Biphasic Solvent Systems

Gongzhe Chen †, Qianhui Sun †, Jia Xu †, Lufan Zheng †, Junfeng Rong †, Baoning Zong †,*
PMCID: PMC7970464  PMID: 33748593

Abstract

graphic file with name ao0c05857_0010.jpg

Biphasic systems have received increasing attention for acid-catalyzed dehydration of hexoses to 5-hydroxymethylfurfural (HMF) because of their high efficiency in in situ extraction and stabilization of HMF. Different organic solvents and acid catalysts were applied in these systems, but their effects on the dehydration activity and HMF yield, and the recycling of homogeneous acid catalysts remain largely unexplored. Here, we tested different solvent systems containing a wide range of organic solvents with low boiling points to study the effects of their chemical structures on fructose dehydration and provided stable H2O–dioxane and H2O–acetonitrile biphasic systems with high HMF yields of 76–79% using water-soluble sulfonic derivatives as homogeneous acid catalysts under mild conditions (383 K). By analyzing the partition coefficients of HMF and sulfonic derivatives, 94.3% of HMF and 87.1% of NH2SO3H were, respectively, restrained in the dioxane phase and aqueous phase in the H2O–dioxane biphasic system and easily divided by phase separation. The effects of the adjacent group in sulfonic derivatives and reaction temperature on fructose conversions and HMF yields suggest that in a specific biphasic system, the catalysts’ acidity and reaction conditions significantly affect the fructose dehydration activity but hardly influence the optimal yield of HMF, and an almost constant amount of carbon loss was observed mainly due to the poor hydrothermal stability of fructose. Such developments offer a promising strategy to address the challenge in the separation and recycling of homogeneous acid catalysts in the practical HMF production.

Introduction

5-Hydroxymethylfurfural (HMF), mainly obtained from acid-catalyzed dehydration of carbohydrates, has been identified as a top value-added biomass-derived intermediate to link up the biomass resource and chemical industry.1−6 As it contains an aldehyde group and a hydroxymethyl group, HMF can serve as a key and versatile platform molecule to produce a series of biofuels such as 2,5-dimethylfuran and 5-ethoxymethylfurfural3,7 and biochemicals such as levulinic acid,8,9 γ-valerolactone,10,11 and 2,5-furandicarboxylic acid.12−14 Thus, effective and efficient methods for HMF production drew continuous attention in the last decade.

As reported, solvents play an important role in HMF production, and some polar aprotic solvents,3,15 for instance, dimethyl sulfoxide (DMSO)16−18 and dimethylacetamide (DMA),19,20 are employed as the reaction medium initially. In particular, DMSO is the most frequently reported reaction solvent as it provides the best HMF yield due to its unique solvent effects on catalysts, reactants, intermediates, and products.21,22 Nonetheless, the high boiling point of DMSO (462 K under atmospheric pressure) leads to the difficulty in the separation of product from solvent, and consequently, the fructose dehydration in the low-boiling-point solvents,23,24 such as tetrahydrofuran (THF, b.p. 339 K under atmospheric pressure), methyl isobutyl ketone (MIBK, b.p. 389 K under atmospheric pressure), and butanol (b.p. 391 K under atmospheric pressure), attracts significant attention to fulfill the industrial production for HMF. However, these low-boiling-point solvents have several disadvantages, for example, poor fructose solubility and low HMF selectivity and yield. Afterward, NaCl is introduced to build biphasic systems between such low-boiling-point solvents and water due to its salting-out effect.25 In these biphasic systems, an aqueous or modified aqueous solution is utilized as the reactive phase for improving fructose solubility and promoting fructose dehydration, while the organic solvent acts as the extracting phase for the continuous extraction and stabilization of HMF from the reactive phase after its formation, leading to much higher HMF yields compared to the results in the organic solvents alone.1 For example, Yang et al.24 generated an HMF yield of 61% from fructose in 10 min catalyzed by AlCl3 in the H2O–THF biphasic system at 433 K. Mazzotta et al.26 synthesized a carbonaceous heterogeneous catalyst of Glu–TsOH–Ti to promote fructose dehydration in a H2O–MeTHF biphasic system at 453 K, with an HMF yield of 59% after 10 min. Ma et al.27 gave an HMF yield of 73.6% in a H2O–MIBK biphasic system without the addition of any external catalysts at 433 K for 2 h. Saha et al.28 conducted the fructose dehydration in a H2O–MIBK biphasic system over Zr(O)Cl2 via microwave heating at 393 K, providing an HMF yield of 63% after 5 min. Dutta et al.29 found that the large-pore mesoporous tin phosphate (LPSnP-1) material showed excellent catalytic activity for fructose dehydration in a H2O–MIBK biphasic system and gave an HMF yield of 77% under microwave-assisted heating at 423 K after 20 min. Yang et al.30 investigated the effects of catalyst content and reaction temperature on HMF yield in a H2O–butanol biphasic system and achieved the maximum HMF yield of 90% at 433 K in 100 min over modified hydrated tantalum oxide. Jiang et al.31 used formic acid to catalyze fructose dehydration in a H2O–butanol biphasic system at 433 K, achieving an HMF yield of 69.2% at 98.3% fructose conversion within 70 min. Extensive research has been conducted on the application of solvents; however, high reaction temperatures (≥433 K) are generally required, and the key relationship between catalytic activity and solvent properties has not been well elucidated. Thus, the effects of organic phases with low boiling points on fructose dehydration activity need intensive study, and HMF yields should be further improved under mild reaction conditions.

Besides the effectiveness of the solvents for promoting selectivity and yield in HMF synthesis, the acid catalyst is another main component that facilitates the dehydration of fructose. Two possible Brønsted acid catalyzed mechanisms of fructose dehydration to HMF are reported, including annular dehydration (Scheme 1a) and chain dehydration mechanism (Scheme 1b),32 and both heterogeneous and homogeneous acid catalysts work in this reaction.3,4,15 The solid acids, for example, acidic ion-exchange resins,33,34 zeolites,35,36 heteropoly acids,37 sulfonated carbon,38 polymer,39 and metal oxide,40 are preferred due to their ease of separation. However, such solid acids are easily inactivated by soluble byproducts with high molecular weights, such as humins, and require regular regeneration.41 Moreover, the limitations of the reactants’ diffusion and mass transfer over heterogeneous catalysts significantly affect their activity.42,43 Compared with solid acids, the liquid acids including HNO3,44 HCl,23,25 H2SO4,45,46 and other common organic acids47,48 have free access to reactants, facilitating the mass transfer between protons and reactants and leading to higher dehydration activity and HMF yield. For example, Antal et al.32 used H2SO4 as a catalyst to prepare HMF from fructose in subcritical water, in which the fructose was completely converted and the HMF yield was up to 53.0% at 523 K after 32 s. Dumesic and co-workers23 investigated the dehydration of fructose through HCl in DMSO, and more than 80% HMF selectivity at 90% fructose conversion was observed at 453 K within 3 min. De Souza et al.47 evaluated a series of organic acids for HMF production, with maximum yields of 48–64% and selectivities of 54–69% at different concentrations under 423 K for 2 h. Although the inexpensive liquid acids have great potential to produce HMF in a large scale since the dehydration of fructose over such acids is accomplished with high efficiency, their disadvantages in separation and recovery limit their further application. Consequently, valid methods for separation and recycling of liquid acids should be established to broaden the path for the industrial production of HMF.

Scheme 1. The Reaction Mechanism of Fructose Dehydration to HMF.

Scheme 1

Open in a new tab

As aforementioned, the sulfonic derivatives are applied as efficient homogeneous catalysts in fructose dehydration due to their strong Brønsted acid site of −SO3H. Moreover, some kinds of sulfonic derivatives, such as sulfamic acid (NH2SO3H), are soluble in water but immiscible in some organic solvents. Therefore, combined with the superiority of the biphasic system in the in situ extraction of HMF into the organic phase, these kinds of acid catalysts remained in an aqueous phase and can be feasibly separated from the product and reused by simple phase separation (Scheme 2).

Scheme 2. The Biphasic System Model for HMF Production and Homogeneous Acid Catalyst Separation.

Scheme 2

Open in a new tab

Herein, in this work, the biphasic systems that contained a low-boiling-point solvent as the organic phase and specific sulfonic derivatives as acid catalysts were used in fructose dehydration to HMF. The fructose dehydration activity and HMF yield were compared in the presence of a wide range of biphasic solvents and acid catalysts. The structural effects of organic phases and acid catalysts on the stability of biphasic systems and the activity of fructose dehydration have been probed. Additionally, the distribution of HMF and the acid catalyst in biphasic systems was examined after the reaction. Based on these results and optimized reaction conditions, several stable biphasic systems with good partition coefficients of HMF and acid catalysts were carried out and gave high HMF yields of up to 79.3% in fructose dehydration. This work demonstrates an effective and applicable strategy for HMF synthesis and homogeneous acid catalyst recovery via these biphasic systems and provides insights into the catalytic functions, solvent effects, reaction parameters, and industrial production for the sugar dehydration to HMF.

Experimental Section

Catalyst Preparation

The corresponding acid catalysts including NH2SO3H, H2SO4, CH3SO3H, CF3SO3H, sulfosalicylic acid, p-toluenesulfonic acid, and sulfanilic acid were purchased commercially from Innochem and used for fructose dehydration directly.

Catalytic Fructose Dehydration and Product Analysis

The fructose dehydration was performed in a thick-walled tube (total volume of 15 mL, Synthware Glass). In a typical run, 0.5 g of fructose (TCI), 0.18 g of NaCl (AR, Sinopharm Chemical Reagent Co., Ltd.), and 0.12 g of NH2SO3H were added into the tube, respectively. Afterward, 1.5 mL of deionized water and 8.5 mL of organic solvent (i.e., ethanol (AR), propanol (AR), butanol (AR), isopropanol (AR), isobutanol (AR), acetone (AR), 2-butanone (AR), methyl isobutyl ketone (MIBK, AR), cyclohexanone (AR), dioxane (AR), tetrahydrofuran (THF, AR), ethyl acetate (AR), γ-valerolactone (GVL, AR), acetonitrile (AR), xylene (AR), cyclohexane (AR), and dimethyl sulfoxide (DMSO, AR); all purchased from Innochem) were supplemented into the reactor. The constant concentration of NaCl and NH2SO3H in the aqueous phase was 0.12 and 0.08 g/mL, respectively. For H2SO4 and CH3SO3H, 1.5 mL of the corresponding diluted solution (containing the same total amount of −SO3H with 0.12 g of NH2SO3H, i.e., 0.04 g/mL of the H2SO4 solution and 0.08 g/mL of the CH3SO3H solution) instead of deionized water was added into the tube. Then, the reactions were carried out at 383 K for different durations with stirring at 600 rpm. After the reaction, the solutions were diluted with deionized water to 100 mL and then the biphasic solution turned to the monophasic solution. For immiscible organic solvents, the biphasic solution should be diluted with ethanol instead of water to generate the monophasic solution for analysis. Products in diluted liquid solutions were analyzed on a high-performance liquid chromatography (HPLC, Agilent Technologies 1260 Infinity II) system equipped with a refractive index (RID) detector and an Aminex HPX-87H ion exclusion column using 0.5 g/L H2SO4 aqueous solution as the mobile phase with a flow rate of 0.6 mL/min at 323 K. The fructose conversion was determined by the mass difference of fructose before and after reaction; selectivity of product i was calculated as (mol of carbon in product i)/(mol of carbon in converted fructose); yield of product i was calculated as (mol of carbon in product i)/(mol of carbon in initial fructose).

The Determination of HMF Distribution

To determine the HMF distribution in biphasic systems, the organic phase and aqueous phase were separated by separatory funnel after reaction. Next, both organic phase and aqueous phase were diluted and analyzed by the same method mentioned above. Afterward, the HMF amount in each phase was obtained, and the partition coefficient of HMF (R1) was calculated as (mol of HMF in the organic phase)/(mol of HMF in the aqueous phase).

The Determination of Acid Distribution

To avoid the disturbance from chromophores in HMF and byproducts (such as humins) during titration, the biphasic systems that contained specific amounts of homogeneous acid catalysts were built in the absence of fructose. Then, the organic phase and aqueous phase were separated by separatory funnel and titrated with an aqueous solution of sodium hydroxide (0.1 mol/L) using phenolphthalein as indicator. The acid amount for each phase equals to the moles of sodium hydroxide used in titration, and the partition coefficient of acid catalysts (R2) was calculated as (mol of the acid catalyst in the aqueous phase)/(mol of the acid catalyst in the organic phase).

Results and Discussion

The Effects of Organic Solvents in the Biphasic Systems on Fructose Dehydration

To acquire a preferable organic solvent in the biphasic system with an aqueous phase and explore the intrinsic effects of the chemical structures of these solvents on the fructose dehydration and HMF yield, a series of candidates including hydrocarbons, alcohols, ketones, esters, ethers, and nitrogenous solvents, especially for those with low boiling points, were screened using NH2SO3H as the acid catalyst, which is soluble in water but immiscible in most of these organic solvents. In all assessed biphasic systems with different organic solvents, similar variation tendencies of fructose conversion (Figure S1a–S6a) and HMF selectivity (Figure S1b–S6b) along with reaction time were observed. During the fructose dehydration, the fructose conversion increased gradually to 100% as the reaction time extended, yet the HMF selectivity first improved to a maximum value after an optimal reaction time and then decreased since the conversion rate of HMF to byproducts (such as formic acid (FA), levulinic acid (LA), and humins) exceeded its production rate. Due to the volcanic-type trend of HMF selectivity, the HMF yield also exhibited a similar variation tendency (Figure S1c–S6c), and the optimal HMF yield was obtained within a certain reaction time as well. The optimal HMF yield and corresponding fructose conversion and product distribution of each system obtained at 383 K were summarized in Table 1, and the images of the biphasic state of the assessed systems were shown in Figure S1d–S6d.

Table 1. The Optimal Performance of Fructose Dehydration in Various Organic Solventsa.

        selectivity (%)
  
entry solvent time (h) conversion (%) FA LA HMF HMF yield (%)
1 toluene 2.0 83.7 3.8 12.6 50.5 42.3
2 xylene 2.0 87.7 4.8 15.4 46.5 40.8
3 cyclohexane 2.0 82.8 4.2 18.9 38.1 31.6
4 ethanol 2.5 88.7 0.2 0.7 66.5 59.0
5 propanol 3.0 91.9 0.3 1.0 63.3 58.2
6 butanol 3.5 92.3 0.3 1.0 59.6 55.1
7 isopropanol 2.0 96.7 0.4 1.1 74.8 72.3
8 isobutanol 3.0 93.3 0.4 1.0 60.6 56.6
9 acetone 2.5 98.1 0.4 1.1 76.0 74.5
10 butanone 2.5 95.8 0.7 2.9 71.4 68.4
11 MIBK 3.5 96.5 1.3 5.6 66.8 64.4
12 ethyl acetate 1.5 95.8 0.4 1.5 70.5 67.5
13 GVL 2 99.0 0.6 2.6 76.6 75.8
14 THF 3.5 96.2 0.5 1.2 63.1 60.7
15 dioxane 2.5 99.1 1.2 2.6 76.9 76.2
16 acetonitrile 2.5 98.9 0.3 0.9 77.8 76.9
Open in a new tab
a

Reaction conditions: 0.5 g of fructose, 8.5 mL of organic solvent, 1.5 mL of deionized water, 0.18 g of NaCl, 0.12 g of NH2SO3H, and 383 K.

As shown in Table 1 (entries 1–3) and Figure S1, the hydrocarbon solvents of toluene, xylene, and cyclohexane were not appropriate candidates since a huge amount of sponge-like humins formed (Figure S1d), and thereby, they provided inferior HMF yields of 42.3, 40.8, and 31.6%, respectively. Beyond that, their phase interfaces between the organic and aqueous phases were indefinable after fructose dehydration (Figure S1d), which could be ascribed to the fact that the humins with macromolecular structure and abundant hydroxyl groups altered the distribution of the aqueous and organic phases.

For alcohol solvents, including ethanol, propanol, butanol, isopropanol, and isobutanol, as the carbon chain length of the straight-chain alcohols elongated from ethanol to butanol, the fructose conversion decreased for each reaction time under the same condition (Figure S2a). For example, in the system of H2O–ethanol, the fructose conversion reached 88.7% with an optimal HMF yield of 59.0% after 2.5 h (Table 1, entry 4), while the fructose conversions were 86.2 and 78.4% in the H2O–propanol and H2O–butanol systems, respectively (Figure S2a), indicating that the length of carbon chain was essential to the fructose dehydration activity. Due to the poor dehydration activity, the H2O–propanol and H2O–butanol systems required a longer time of 3.0 and 3.5 h to reach their corresponding optimal HMF yields of 58.2 and 55.1% (Table 1, entries 5–6), respectively, which were lower than that in the H2O–ethanol system as well. Similarly, the H2O–isopropanol system (Table 1, entry 7) provided higher fructose conversion (96.7%) and HMF yield (72.3%) in a shorter optimal reaction time (2 h) than those in the H2O–isobutanol system, in which the fructose conversion, HMF yield, and optimal reaction time were 93.3%, 56.6%, and 3.0 h, respectively (Table 1, entry 8). Based on the aforementioned results, an interesting phenomenon was observed, i.e., the dehydration activities and HMF yields given by the systems containing branched alcohol solvents (i.e., H2O–isopropanol and H2O–isobutanol) were superior to those of their corresponding systems containing straight-chain alcohol solvents (i.e., H2O–propanol and H2O–butanol), which indicated that the presence of a side chain improved the catalytic efficiency of fructose dehydration. However, only the systems containing butanol and isobutanol expressed a biphasic state after the reaction due to the strong immiscibility of these two alcohols with the saline aqueous phase, while ethanol, propanol, and isopropanol were highly mutually soluble with water (Figure S2d).

The relationship between the fructose dehydration activity and carbon chain length was consistent in H2O–ketone solvents as well. As displayed in Figure S3, the H2O–acetone system presented the highest fructose conversion and HMF yield for each reaction time compared to other ketone solvents, including butanone and MIBK. In addition, the H2O–acetone system gained its optimal HMF yield of 74.5% at 98.1% fructose conversion after 2.5 h (Table 1, entry 9), while the H2O–butanone and H2O–MIBK systems afforded gradually falling optimal HMF yields of 68.4 and 64.4% as the carbon number of these ketones increased (Table 1, entries 10–11). The systems containing acetone and butanone displayed a biphasic state after reaction, while in the H2O–MIBK system, sponge-like humins were also observed during the reaction and altered the distribution of MIBK and water, making the biphasic state of this system indefinable (Figure S3d).

For the tested ester solvents, in the H2O–ethyl acetate system, the optimal HMF yield of 67.5% at 95.8% fructose conversion was achieved after 1.5 h (Table 1, entry 12). Additionally, although ethyl acetate is slightly soluble in water, the biphasic state of the H2O–ethyl acetate system collapsed after reaction (Figure S4d) due to the hydrolysis reaction of ethyl acetate to ethanol and acetic acid in the presence of acid catalysts. GVL is reported as an outstanding solvent for HMF production,49,50 and in this work, the H2O–GVL system exhibited a biphasic state (Figure. S4d) as well as provided the optimal HMF yield of 75.8% at 99.0% fructose conversion after 2 h (Table 1, entry 13). However, GVL is not an appropriate solvent candidate in this work due to its high boiling point of 480 K under atmospheric pressure.

THF and dioxane were also tested in this work as two typical cyclic ether solvents. THF is widely utilized in the biphasic system due to its extremely high partition coefficient of HMF.23−25 However, although the H2O–THF system expressed a clear biphasic state (Figure S5d), it spent no less than 3.5 h to gain the optimal HMF yield of 60.7% at a fructose conversion of 96.2% (Table 1, entry 14). Meanwhile, dioxane also generated a biphasic state with a saline aqueous phase (Figure S5d), and compared with THF, the H2O–dioxane biphasic system afforded an ascendant dehydration rate as the fructose conversion was improved for each reaction time (Figure S5a). An outstanding optimal HMF yield of 76.2% was obtained at 99.1% fructose conversion after 2.5 h in the H2O–dioxane biphasic system over NH2SO3H (Table 1, entry 15).

As a nitrogenous solvent with a low boiling point, acetonitrile also created a biphasic state with a saline aqueous phase due to the salting-out effect of NaCl (Figure S6d), and among the screened solvents, it gave the highest optimal HMF yield of 76.9% at 98.9% fructose conversion after 2.5 h over NH2SO3H (Table 1, entry 16).

Therefore, according to the overall results, the different types of organic solvents imposed a significant effect on the stability of biphasic systems and the activity of fructose dehydration. And the length and structure of carbon chains for the same type of organic solvents also played a crucial role in controlling the fructose dehydration activity and selectivity to HMF. Among all of the assessed organic solvents, dioxane and acetonitrile are the most advisable solvent candidates with a low boiling point in the biphasic system for the catalytic dehydration of fructose to HMF, which, respectively, afforded 76.2 and 76.9% HMF yields over NH2SO3H at 383 K.

The Effects of Water Content in the Biphasic Systems on Fructose Dehydration

As reported, in a pure organic solvent, the HMF selectivity and yield are inhibited because of the fructose oligomerization to difructose anhydride. Thus, water is required to hydrolyze the oligomers and helps to raise the HMF yield.36 But a higher water content usually accompanies higher selectivities to byproducts such as FA, LA, and humins.3 Therefore, the appropriate water content is significant for the biphasic systems for hexose dehydration to HMF. The catalytic dehydration of fructose was conducted in a H2O–dioxane biphasic system with a water content range from 5 to 25 vol % at 383 K where NH2SO3H was used as the acid catalyst. As shown in Figure 1a, within the same reaction time of 1 h, the fructose conversion decreased from 98.3 to 76.3% as the water content increased from 5 to 25 vol %, suggesting that the higher water content significantly hindered the fructose dehydration rate.41

Figure 1.

Figure 1

Open in a new tab

Fructose conversion after 1 h (a) and optimal HMF yield (b) in the H2O–dioxane biphasic system with various water contents. Reaction conditions: 0.5 g of fructose, 10.0 mL of reaction solvent, 0.12 g/mL of NaCl in the aqueous phase, and 0.08 g/mL of NH2SO3H in the aqueous phase.

However, the accelerated dehydration rate in low water content was not accompanied by higher HMF yield. The optimal HMF yield of 70.9%, obtained with a water content of 5 vol % after 2.5 h, was the lowest one in this set of experiments (Figure S7c). This is likely ascribed to the fact that the small water content could not provide enough phase interface area between the organic and aqueous phases during the reaction (Figure S8a), and thus, the HMF extraction was limited and more HMF was further converted to byproducts in the aqueous phase.

As water content ascended, the phase interface area increased gradually (Figure S8), and thus, the HMF extraction was enhanced during the reaction. Consequently, the optimal HMF yield further rose to 76.2% as the water content increased up to 15 vol %. However, the optimal HMF yield decreased when more than 15 vol % water was added into the system and was reduced to 74.1% when the water content was elevated to 25 vol % (Figure 1b). This is attributed to the fact that the higher water content favored the conversion of HMF to byproducts of FA and LA, where the sum of FA and LA selectivity increased from 3.8 to 5.0% as the water content increased from 15 to 25 vol % (Table S1, entries 3–5). However, unlike the aforementioned significant decrease in the fructose dehydration rate within the water content range of 10 to 25 vol % (Figure S7a), the differences in the optimal HMF yields were less obvious (74.1–76.2%, Figure S7c).

The relationship between water content and fructose dehydration activity was also observed in the H2O–acetonitrile biphasic system, where the highest HMF yield of 76.9% over NH2SO3H at 383 K was acquired with the appropriate water content of 15 vol % (Figure S9c), demonstrating the importance of the adjustment of water content in the biphasic system.

HMF Extraction by the Organic Phase

The main role of the organic phase is to extract HMF from the aqueous phase during fructose dehydration; thus, the partition coefficient of HMF (R1), determined by the ratio of HMF quantified in the organic and aqueous phase, is the primary parameter to probe the HMF extraction efficiency of the biphasic system. The HMF partition coefficients of the H2O–dioxane and H2O–acetonitrile biphasic systems were measured and listed in Table 2. The results illustrated that the H2O–acetonitrile biphasic system had a larger R1 value of 25.6 than that of 16.6 in the H2O–dioxane biphasic system, which manifested that 96.2 and 94.3% of HMF could be extracted into acetonitrile and dioxane, respectively, after reaction, demonstrating the high HMF extraction efficiency in these two biphasic systems.

Table 2. HMF Partition Coefficients of Organic Solvents in Biphasic Systemsa.

entry solvent R1 (HMForg (mol)/HMFaq (mol))
1 dioxane 16.6
2 acetonitrile 25.6
Open in a new tab
a

Reaction conditions: 0.5 g of fructose, 8.5 mL of organic solvent, 1.5 mL of deionized water, 0.18 g of NaCl, 0.12 g of NH2SO3H, 383 K, and 2.5 h.

Acid Extraction by the Aqueous Phase

As NH2SO3H is soluble in water but immiscible in most of the organic solvents, theoretically, NH2SO3H could be retained in the aqueous phase preferably after reaction, and thus, the separation of the product and acid catalyst is accomplished by the separation of the organic phase and aqueous phase. Analogously, the acid partition coefficient (R2) was utilized here to determine the recover ratio of some common sulfonic derivatives, including NH2SO3H, H2SO4, CH3SO3H, CF3SO3H, sulfosalicylic acid, p-toluenesulfonic acid, and sulfanilic acid, which were widely used as acid catalysts. As described in Table 3, in the H2O–dioxane biphasic system, the R2 of NH2SO3H was 6.76, elucidating that 87.1% of NH2SO3H was retained in the aqueous phase (Table 3, entry 1). The small amount of NH2SO3H (12.9%) in the organic phase was probably ascribed to the following: (i) a trace amount of NH2SO3H was dissolved in the organic phase, and (ii) not all of the water was separated from the organic phase by the salting-out effect, and a trace amount of water that contained NH2SO3H remained in the organic phase. For H2SO4 and CH3SO3H, although they were soluble in both water and ether solvents, their corresponding R2 values were 2.96 and 1.97, respectively, in this H2O–dioxane biphasic system, indicating that 74.8% of H2SO4 and 66.3% of CH3SO3H could also be recovered in the aqueous phase directly (Table 3, entries 2–3). While the −SO3H was grafted on benzene, for instance, sulfosalicylic acid and p-toluenesulfonic acid, the R2 values dropped to 0.63 and 0.35, respectively (Table 3, entries 4–5), which implied that these sulfonic derivatives with the phenyl group had great solubility in the organic phase and less than 38.7% of the acids were recovered in the aqueous phase.

Table 3. Acid Partition Coefficients of Sulfonate Derivatives in Biphasic Systemsa.

graphic file with name ao0c05857_0009.jpg

Open in a new tab
a

Conditions: 8.5 mL of organic solvent, 1.5 mL of deionized water, 0.18 g of NaCl, and 0.12 g of NH2SO3H (other acids contained the same total amount of −SO3H with NH2SO3H).

b

“-” means the R2 could not be measured.

In the H2O–acetonitrile biphasic system, the R2 values of NH2SO3H, H2SO4, CH3SO3H, sulfosalicylic acid, and p-toluenesulfonic acid were 4.44, 1.90, 1.11, 0.37, and 0.12, respectively (Table 3, entries 1–4), which were smaller than the corresponding values in the H2O–dioxane biphasic system.

For other sulfonic derivatives, such as CF3SO3H, the biphasic state was not created in both H2O–dioxane and H2O–acetonitrile biphasic systems (Figure S10a,c), making the CF3SO3H distribution undetermined (Table 3, entry 6). The sulfanilic acid was insoluble in both water and organic phases in these two biphasic systems (Figure S10b and S10d), and hence, the acid distribution was undetermined either (Table 3, entry 7).

Based on these R2 values, the adjacent functional groups of the acid site were found to play an essential role in controlling the recovery ratio of sulfonic derivatives in the aqueous phase. Other than NH2SO3H, H2SO4 and CH3SO3H also afforded relatively larger R2 values in biphasic systems, so afterward, the catalytic performance of H2SO4 and CH3SO3H for fructose dehydration in H2O–dioxane and H2O–acetonitrile biphasic systems was characterized in the subsequent section.

Fructose Dehydration over Different Sulfonic Derivatives

In the presence of H2SO4 and CH3SO3H, both H2O–dioxane and H2O–acetonitrile biphasic systems displayed a clear biphasic state after the reaction (Figure S11). As presented in Figure S12a, in the H2O–dioxane biphasic system, CH3SO3H expressed a similar but slightly ascensive dehydration rate to H2SO4 since the fructose conversion over CH3SO3H was slightly higher than that over H2SO4 for each reaction time. Within the reaction time of 20 min, the fructose conversion over CH3SO3H was 98.7%, while it was 96.9% over H2SO4. Moreover, both CH3SO3H and H2SO4 expressed much improved dehydration rates than NH2SO3H as the fructose conversion over NH2SO3H was less than 72.7% after the same reaction time (Figure S12a). The possible reason to the lower dehydration activity of NH2SO3H is that its acidity was reduced due to the basicity of −NH2. A similar trend was also observed in the H2O–acetonitrile biphasic system, where the fructose conversion was 99.2% and 95.6% after 20 min over CH3SO3H and H2SO4, respectively, while it was less than 83.6% over NH2SO3H (Figure S13a). According to these results, the adjacent functional groups of the −SO3H site in these sulfonic derivatives were demonstrated to play an essential role in promoting the fructose dehydration rate, possibly due to their differences in acidity.

The optimal performances of fructose dehydration over different sulfonic derivatives in the H2O–dioxane and H2O–acetonitrile biphasic systems were summarized in Figure 2. The results illustrated that opposite to the sequence of acid recovery ratio (R2) in the aqueous phase, NH2SO3H, H2SO4, and CH3SO3H provided a rising HMF yield in both H2O–dioxane (76.2%, 76.6%, and 77.5%) and H2O–acetonitrile biphasic systems (76.9%, 78.4%, and 79.3%). Although these acid catalysts exhibited distinctly different dehydration activity and required different reaction time to achieve their optimal HMF yields (Table S2), the H2O–dioxane and H2O–acetonitrile biphasic systems both gave a narrow range for optimal HMF yields, respectively (76.2–77.5 and 76.9–79.3%), suggesting that the optimal HMF yields had not been much affected by the dehydration activities over these acid catalysts.

Figure 2.

Figure 2

Open in a new tab

The optimal performance of fructose dehydration over different acid catalysts in biphasic systems. Reaction conditions: 0.5 g of fructose, 8.5 mL of organic solvent, 1.5 mL of deionized water, 0.18 g of NaCl, 0.12 g of NH2SO3H (other acids contained the same −SO3H amount as NH2SO3H), and 383 K.

The effect of the total acid content on the fructose dehydration conversion was also tested over NH2SO3H in the H2O–dioxane biphasic system. As exhibited in Figure S14a, within the reaction time of 1.0 h, the fructose conversion increased from 84.6 to 96.3% along with the growing dosage of NH2SO3H from 0.09 to 0.24 g. And due to the improved dehydration rate of fructose, the optimal reaction time for the optimal HMF yields was reduced from 3.0 to 1.5 h (Figure S14c). However, the optimal HMF yields were just varied in the narrow scope of 74.8–76.2% (Table S3) as the catalyst dosage multiplied and the fructose dehydration rate further increased, displaying the irregularity between the optimal HMF yields and the fructose dehydration activity, which will be further discussed below.

The Effects of Reaction Conditions on Fructose Dehydration

As aforementioned, Figure 2 presents about 20% loss in carbon balance during the fructose dehydration, which was mainly ascribed to the side reaction among substrates, intermediates, and products to the unquantifiable humins.3 In an attempt to reduce humin formation and further improve HMF yield, the reaction rate and time were further regulated by varying reaction conditions, including reaction temperature and fructose input, in the H2O–acetonitrile biphasic system using CH3SO3H as the acid catalyst, which showed the highest HMF yield as discussed in Figure 2.

As described in Table S4, in the H2O–acetonitrile biphasic system, it required 4.5 h to reach 99% fructose conversion at 363 K (entry 5), while it only needed 20 min (entry 8) or less than 9 min (entry 12) to reach the same fructose conversion over CH3SO3H at 383 or 403 K, respectively, indicating that the rate of fructose dehydration increased with the temperature elevating, as expected. However, while the rate of fructose dehydration increased significantly by increasing the reaction temperature, the optimal HMF yields obtained at each temperature were just varied in a narrow range of 77.2–79.3% (Table 4).

Table 4. The Optimal Performance of Fructose Dehydration under Various Reaction Temperaturesa.

        selectivity (%)
  
entry temperature (K) time conversion (%) FA LA HMF HMF yield (%)
1 363 4.0 h 98.8 0.6 1.4 78.2 77.2
2 383 20 min 99.2 0.2 0.6 79.9 79.3
3 403 9 min 99.7 0.2 0.6 77.9 77.6
Open in a new tab
a

Reaction conditions: 0.5 g of fructose, 8.5 mL of acetonitrile, 1.5 mL of deionized water, 0.18 g of NaCl, and 0.12 g of CH3SO3H.

Lower fructose concentrations were reported to generate an elevated HMF selectivity, thereby allowing a higher HMF yield.25 Therefore, the conversion of fructose dehydration with smaller fructose inputs was examined. The catalytic dehydration of fructose was conducted in the H2O–acetonitrile biphasic system with a fructose input range from 0.2 to 0.5 g at 383 K, where CH3SO3H was used as the acid catalyst with a constant dosage of 0.12 g. The fructose conversion and HMF yield expressed almost identical curves independent of fructose input (Figure S15). As displayed in Figure 3a, the fructose conversion obtained after 10 min for each fructose input was at almost the same level of 91.1–92.6%. The optimal HMF yields for each fructose input were all acquired within 20 min (Figure S15c), at almost the same level of 78.9–79.5% as well (Figure 3b), suggesting that the fructose concentration had no obvious impact on raising the optimal HMF yields.

Figure 3.

Figure 3

Open in a new tab

Fructose conversion after 10 min (a) and optimal HMF yield (b) in the H2O–acetonitrile biphasic system with various fructose inputs. Reaction conditions: 0.2–0.5 g of fructose, 8.5 mL of organic solvent, 1.5 mL of deionized water, 0.18 g of NaCl, 0.12 g of CH3SO3H, and 383 K.

The aforementioned fructose dehydration results in a specified biphasic system (i.e., H2O–dioxane or H2O–acetonitrile) with various water contents (Figure 1), catalyst acidities (Figure 2) and dosages (Figure S14), reaction temperatures (Table 4), and substrate inputs (Figure 3) demonstrate that the catalysts and reaction conditions could obviously affect the fructose dehydration activity but played a subtle role in controlling the carbon loss to humins, leading to an almost constant value of the optimal HMF yield. Namely, the optimal HMF yield in a specified biphasic system seems mainly determined by the properties of the organic phase instead of the catalysts and reaction conditions. Herein, as an apparent parameter reflecting the interaction between HMF yields and organic phases, the partition coefficients of HMF (R1) in several biphasic systems with definite biphasic state, including dioxane, THF, acetonitrile, acetone, butanone, GVL, isobutanol, and butanol, were determined and correlated to their corresponding optimal yields (Figure S16). However, an obvious relationship between the HMF partition coefficients (R1) and the optimal HMF yields was observed, indicating that the constant amount of carbon loss and HMF production was dominated by some other intrinsic properties of the organic phases in biphasic systems, which could be further studied in future works to give more insights to the effective synthesis of HMF.

The Hydrothermal Stability of HMF and Fructose in the Biphasic Systems

To probe the mechanism of humin formation in the biphasic systems, the hydrothermal stability of HMF under the same optimal reaction conditions with fructose dehydration was examined. As described in Table 5, the H2O–dioxane biphasic system gave HMF loss ratios of 4.0, 3.5, and 3.4% over NH2SO3H, H2SO4, and CH3SO3H (Table 5, entries 1–3), respectively, after the optimal reaction time (obtained from Figure S12). Meanwhile, in the H2O–acetonitrile biphasic system, the HMF loss ratios were 2.0, 2.5, and 2.4% over these three acid catalysts (Table 5, entries 4–6), respectively, after the optimal reaction time (obtained from Figure S13), which were relatively lower than those in the H2O-dioxane biphasic system, elucidating that acetonitrile could stabilize HMF better than dioxane, which was in accordance with the fact that the H2O–acetonitrile biphasic system possessed a larger partition coefficient of HMF (R1) than that of the H2O–dioxane biphasic system. Additionally, in both H2O–dioxane and H2O–acetonitrile biphasic systems, the HMF loss ratios were pretty close (3.4–4.0 and 2.0–2.5%, respectively) over different acid catalysts within different reaction times, suggesting that the stability of HMF in these biphasic systems was irrelevant to the acid catalysts or reaction time but seems only relevant to the organic phases.

Table 5. The Hydrothermal Stability of HMF in Biphasic Systemsa.

entry solvent catalyst time HMF recovery ratio (%) HMF loss ratio (%)
1 dioxane NH2SO3H 2.5 h 96.0 4.0
2 dioxane H2SO4 30 min 96.5 3.5
3 dioxane CH3SO3H 20 min 96.6 3.4
4 acetonitrile NH2SO3H 2.5 h 98.0 2.0
5 acetonitrile H2SO4 40 min 97.5 2.5
6 acetonitrile CH3SO3H 20 min 97.6 2.4
Open in a new tab
a

Reaction conditions: 0.35 g of HMF, 8.5 mL of organic solvent, 1.5 mL of deionized water, 0.18 g of NaCl, 0.12 g of NH2SO3H (H2SO4 and CH3SO3H contained the same total amount of −SO3H with NH2SO3H), and 383 K.

However, the HMF loss ratios were too small compared to the 20% loss in carbon balance during the fructose dehydration. The hydrothermal stability of fructose in biphasic systems was examined as well, and the results were presented in Figure 4. Even in the absence of acid catalysts, the fructose loss ratio in the H2O–dioxane biphasic system increased from 9.6 to 19.0% as the reaction time extended from 1 to 4 h at 383 K, manifesting the instability of fructose under the reaction conditions. Meanwhile, the fructose loss ratio also ascended from 5.7 to 10.0% in the H2O–acetonitrile biphasic system.

Figure 4.

Figure 4

Open in a new tab

The fructose loss ratio as a function of reaction time in biphasic systems. Reaction conditions: 0.5 g of fructose, 8.5 mL of organic solvent, 1.5 mL of deionized water, 0.18 g of NaCl, and 383 K.

As described above, the HMF loss ratios in the H2O–dioxane and H2O–acetonitrile biphasic systems over NH2SO3H after 2.5 h were 4.0 and 2.0%, respectively, which were much lower than the fructose loss ratios of 12.4 and 8.2% after 2.0 h, respectively, suggesting that HMF was much more stable than fructose in the biphasic systems due to the protection effect from organic phases. Considering that the acid catalysts also contribute to the sugar polymerization to carbon particles,51 in these biphasic systems, fructose is actually more vulnerable than HMF and mainly accounts for the formation of humins through its self-condensation and condensation with intermediates and HMF.52−54 Therefore, further development of catalytical systems that favor the stabilization of products as well as reactants and intermediates is the key strategy to produce HMF with a higher yield.

The Recyclability of the Biphasic System

The biphasic system of H2O–dioxane–CH3SO3H was used to probe its recyclability and stability in five successive reaction runs. After each reaction run, the organic phase was extracted, and then fresh fructose and organic solvent were added. Based on the acid loss of 33.7% discussed in Table 3, the pure CH3SO3H (0.12 × 0.337 = 0.0405 g, approximately 30 μL) was supplemented to refill the acid loss. This biphasic system exhibited excellent recyclability and stability as the fructose conversion and optimal HMF yield were kept at the steady level of 98.7–99.3 and 77.4–78.1%, respectively (Figure 5). Additionally, the organic phase also exhibits a stable extraction efficiency, where the HMF partition ratio remains at the level of 94.3–95.8% (Figure S17).

Figure 5.

Figure 5

Open in a new tab

The fructose conversion (a) and optimal HMF yield (b) in the H2O–dioxane biphasic system in five successive runs. Reaction conditions: 0.5 g of fructose, 8.5 mL of dioxane, 1.5 mL of deionized water, 0.18 g of NaCl, 0.12 g of CH3SO3H, 383 K, and 20 min.

Conclusions

Biphasic systems containing saline solution as the reactive phase and an organic solvent with a low boiling point as the extraction phase are employed in the fructose dehydration to HMF over water-soluble sulfonic derivatives to realize the efficient separation of products and homogeneous acid catalysts, affording an HMF yield of 76.2% in H2O–dioxane over NH2SO3H with 94.3% of HMF extracted in the dioxane phase and 87.1% of NH2SO3H recycled in the aqueous phase, or a higher HMF yield of 79.3% in H2O–acetonitrile over CH3SO3H with 96.2% of HMF extracted in the acetonitrile phase and 66.3% of CH3SO3H recycled in the aqueous phase. The acidity and dosage of the sulfonic derivatives, the water content, and the reaction conditions significantly influence the fructose dehydration activities but show less effect on the corresponding optimal HMF yields in a specific biphasic system, with an almost constant amount of carbon loss to humins. Moreover, HMF presents better hydrothermal stability than fructose in these biphasic systems, suggesting that the humin formation starts from the condensation among sugars and intermediates primarily, and the key strategy to produce HMF with outstanding yield is to design catalytical systems that favor the stabilization of products as well as reactants and intermediates. This study provides a fundamental understanding of fructose dehydration and proposes an applicable model for the industrial HMF production.

Acknowledgments

This research was financially supported by China Petrochemical Corp. (Grant KL20014) and the National Natural Science Foundation of China (Grant 21805309).

Supporting Information Available

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsomega.0c05857.

  • Fructose conversions, HMF selectivities, and HMF yields as a function of reaction time, and biphasic state images in all assessed biphasic systems; fructose conversions, HMF selectivities, and HMF yields as a function of reaction time, and biphasic state images in H2O–dioxane and H2O–acetonitrile biphasic systems with various water contents; fructose conversions, HMF selectivities, and HMF yields as a function of reaction time, and biphasic state images in H2O–dioxane and H2O–acetonitrile biphasic systems over different acid catalysts; fructose conversions, HMF selectivities, and HMF yields as a function of reaction time in H2O–dioxane and H2O–acetonitrile biphasic systems within all assessed reaction conditions; the relationship between optimal HMF yields and HMF partition coefficients provided by organic solvents of all assessed biphasic systems (Figure S1–S17); the optimal performance of fructose dehydration (Table S1–S4) (PDF)

Author Contributions

‡ G.C. and Q.S. contributed equally to this work.

The authors declare no competing financial interest.

Supplementary Material

ao0c05857_si_001.pdf (5.1MB, pdf)

References

  1. Saha B.; Abu-Omar M. M. Advances in 5-hydroxymethylfurfural production from biomass in biphasic solvents. Green Chem. 2014, 16, 24–38. 10.1039/C3GC41324A. [DOI] [Google Scholar]
  2. Xu C.; Paone E.; Rodríguez-Padrón D.; Luque R.; Mauriello F. Recent catalytic routes for the preparation and the upgrading of biomass derived furfural and 5-hydroxymethylfurfural. Chem. Soc. Rev. 2020, 49, 4273–4306. 10.1039/D0CS00041H. [DOI] [PubMed] [Google Scholar]
  3. Wang H.; Zhu C.; Li D.; Liu Q.; Tan J.; Wang C.; Cai C.; Ma L. Recent advances in catalytic conversion of biomass to 5-hydroxymethylfurfural and 2, 5-dimethylfuran. Renewable Sustainable Energy Rev. 2019, 103, 227–247. 10.1016/j.rser.2018.12.010. [DOI] [Google Scholar]
  4. Zhang X.; Wilson K.; Lee A. F. Heterogeneously catalyzed hydrothermal processing of C5-C6 Sugars. Chem. Rev. 2016, 116, 12328–12368. 10.1021/acs.chemrev.6b00311. [DOI] [PubMed] [Google Scholar]
  5. Jing Y.; Guo Y.; Xia Q.; Liu X.; Wang Y. Catalytic production of value-added chemicals and liquid fuels from lignocellulosic biomass. Chem 2019, 5, 2520–2546. 10.1016/j.chempr.2019.05.022. [DOI] [Google Scholar]
  6. Zhang Z.; Song J.; Han B. Catalytic transformation of lignocellulose into chemicals and fuel products in ionic liquids. Chem. Rev. 2017, 117, 6834–6880. 10.1021/acs.chemrev.6b00457. [DOI] [PubMed] [Google Scholar]
  7. Román-Leshkov Y.; Barrett C. J.; Liu Z. Y.; Dumesic J. A. Production of dimethylfuran for liquid fuels from biomass-derived carbohydrates. Nature 2007, 447, 982–985. 10.1038/nature05923. [DOI] [PubMed] [Google Scholar]
  8. Garcés D.; Díaz E.; Ordóñez S. Aqueous phase conversion of hexoses into 5-hydroxymethylfurfural and levulinic acid in the presence of hydrochloric acid: mechanism and kinetics. Ind. Eng. Chem. Res. 2017, 56, 5221–5230. 10.1021/acs.iecr.7b00952. [DOI] [Google Scholar]
  9. Tan J.; Liu Q.; Chen L.; Wang T.; Ma L.; Chen G. Efficient production of ethyl levulinate from cassava over Al2(SO4)3 catalyst in ethanol-water system. J. Energy Chem. 2017, 26, 115–120. 10.1016/j.jechem.2016.08.004. [DOI] [Google Scholar]
  10. Xiao C.; Goh T.-W.; Qi Z.; Goes S.; Brashler K.; Perez C.; Huang W. Conversion of levulinic acid to γ-valerolactone over few-layer graphene-supported ruthenium catalysts. ACS Catal. 2016, 6, 593–599. 10.1021/acscatal.5b02673. [DOI] [Google Scholar]
  11. Luo W.; Sankar M.; Beale A. M.; He Q.; Kiely C. J.; Bruijnincx P. C. A.; Weckhuysen B. M. High performing and stable supported nano-alloys for the catalytic hydrogenation of levulinic acid to γ-valerolactone. Nat. Commun. 2015, 6, 6540–6510. 10.1038/ncomms7540. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Saha B.; Gupta D.; Abu-Omar M. M.; Modak A.; Bhaumik A. Porphyrin-based porous organic polymer-supported iron (III) catalyst for efficient aerobic oxidation of 5-hydroxymethyl-furfural into 2, 5-furandicarboxylic acid. J. Catal. 2013, 299, 316–320. 10.1016/j.jcat.2012.12.024. [DOI] [Google Scholar]
  13. Xu S.; Zhou P.; Zhang Z.; Yang C.; Zhang B.; Deng K.; Bottle S.; Zhu H. Selective oxidation of 5-hydroxymethylfurfural to 2, 5-furandicarboxylic acid using O2 and a photocatalyst of Co-thioporphyrazine bonded to g-C3N4. J. Am. Chem. Soc. 2017, 139, 14775–14782. 10.1021/jacs.7b08861. [DOI] [PubMed] [Google Scholar]
  14. Donoeva B.; Masoud N.; De Jongh P. E. Carbon support surface effects in the gold-catalyzed oxidation of 5-hydroxymethylfurfural. ACS Catal. 2017, 7, 4581–4591. 10.1021/acscatal.7b00829. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Yu I. K. M.; Tsang D. C. W. Conversion of biomass to hydroxymethylfurfural: A review of catalytic systems and underlying mechanisms. Bioresour. Technol. 2017, 238, 716–732. 10.1016/j.biortech.2017.04.026. [DOI] [PubMed] [Google Scholar]
  16. Liu Z.; Zhu L.; Hu C. High-efficiency synthesis of 5-hydroxymethylfurfural from fructose over highly sulfonated organocatalyst. Ind. Eng. Chem. Res. 2020, 59, 17218–17227. 10.1021/acs.iecr.0c01044. [DOI] [Google Scholar]
  17. Zhao J.; Si Z.; Shan H.; Cai D.; Li S.; Li G.; Lin H.; Baeyens J.; Wang G.; Zhao H.; Qin P. Highly efficient production of 5-hydroxymethylfurfural from fructose via a bromine-functionalized porous catalyst under mild conditions. Ind. Eng. Chem. Res. 2020, 59, 14569–14577. 10.1021/acs.iecr.0c01480. [DOI] [Google Scholar]
  18. Wang J.; Xu W.; Ren J.; Liu X.; Lu G.; Wang Y. Efficient catalytic conversion of fructose into hydroxymethylfurfural by a novel carbon-based solid acid. Green Chem. 2011, 13, 2678–2681. 10.1039/c1gc15306d. [DOI] [Google Scholar]
  19. Binder J. B.; Raines R. T. Simple chemical transformation of lignocellulosic biomass into furans for fuels and chemicals. J. Am. Chem. Soc. 2009, 131, 1979–1985. 10.1021/ja808537j. [DOI] [PubMed] [Google Scholar]
  20. Dutta S.; De S.; Alam M. I.; Abu-Omar M. M.; Saha B. Direct conversion of cellulose and lignocellulosic biomass into chemicals and biofuel with metal chloride catalysts. J. Catal. 2012, 288, 8–15. 10.1016/j.jcat.2011.12.017. [DOI] [Google Scholar]
  21. Shuai L.; Luterbacher J. Organic solvent effects in biomass conversion reactions. ChemSusChem 2016, 9, 133–155. 10.1002/cssc.201501148. [DOI] [PubMed] [Google Scholar]
  22. Ren L.-K.; Zhu L.-F.; Qi T.; Tang J.-Q.; Yang H.-Q.; Hu C.-W. Performance of dimethyl sulfoxide and Brønsted acid catalysts in fructose conversion to 5-hydroxymethylfurfural. ACS Catal. 2017, 7, 2199–2212. 10.1021/acscatal.6b01802. [DOI] [Google Scholar]
  23. Román-Leshkov Y.; Chheda J. N.; Dumesic J. A. Phase modifiers promote efficient production of hydroxymethylfurfural from fructose. Science 2006, 312, 1933–1937. 10.1126/science.1126337. [DOI] [PubMed] [Google Scholar]
  24. Yang Y.; Hu C.; Abu-Omar M. M. Conversion of carbohydrates and lignocellulosic biomass into 5-hydroxymethylfurfural using AlCl3·6H2O catalyst in a biphasic solvent system. Green Chem. 2012, 14, 509–513. 10.1039/C1GC15972K. [DOI] [Google Scholar]
  25. Román-Leshkov Y.; Dumesic J. A. Solvent effects on fructose dehydration to 5-hydroxymethylfurfural in biphasic systems saturated with inorganic salts. Top. Catal. 2009, 52, 297–303. 10.1007/s11244-008-9166-0. [DOI] [Google Scholar]
  26. Mazzotta M. G.; Gupta D.; Saha B.; Patra A. K.; Bhaumik A.; Abu-Omar M. M. Efficient solid acid catalyst containing lewis and brønsted acid sites for the production of furfurals. ChemSusChem 2014, 7, 2342–2350. 10.1002/cssc.201402007. [DOI] [PubMed] [Google Scholar]
  27. Ma H.; Wang F.; Yu Y.; Wang L.; Li X. Autocatalytic production of 5-hydroxymethylfurfural from fructose-based carbohydrates in a biphasic system and its purification. Ind. Eng. Chem. Res. 2015, 54, 2657–2666. 10.1021/ie504791x. [DOI] [Google Scholar]
  28. Saha B.; De S.; Fan M. Zr(O)Cl2 catalyst for selective conversion of biorenewable carbohydrates and biopolymers to biofuel precursor 5-hydroxymethylfurfural in aqueous medium. Fuel 2013, 111, 598–605. 10.1016/j.fuel.2013.03.031. [DOI] [Google Scholar]
  29. Dutta A.; Gupta D.; Patra A. K.; Saha B.; Bhaumik A. Synthesis of 5-hydroxymethylfurural from carbohydrates using large-pore mesoporous tin phosphate. ChemSusChem 2014, 7, 925–933. 10.1002/cssc.201300766. [DOI] [PubMed] [Google Scholar]
  30. Yang F.; Liu Q.; Yue M.; Bai X.; Du Y. Tantalum compounds as heterogeneous catalysts for saccharide dehydration to 5-hydroxymethylfurfural. Chem. Commun. 2011, 47, 4469–4471. 10.1039/c0cc05138a. [DOI] [PubMed] [Google Scholar]
  31. Jiang N.; Huang R.; Qi W.; Su R.; He Z. Effect of formic acid on conversion of fructose to 5-hydroxymethylfurfural in aqueous/butanol media. BioEnergy Res. 2012, 5, 380–386. 10.1007/s12155-011-9141-7. [DOI] [Google Scholar]
  32. Antal M. J. Jr.; Mok W. S. L.; Richards G. N. Mechanism of formation of 5-(hydroxymethyl)-2-furaldehyde from d-fructose and sucrose. Carbohydr. Res. 1990, 199, 91–109. 10.1016/0008-6215(90)84096-D. [DOI] [PubMed] [Google Scholar]
  33. Aellig C.; Hermans I. Continuous D-fructose dehydration to 5-hydroxymethylfurfural under mild conditions. ChemSusChem 2012, 5, 1737–1742. 10.1002/cssc.201200279. [DOI] [PubMed] [Google Scholar]
  34. Simeonov S. P.; Coelho J. A. S.; Afonso C. A. M. An integrated approach for the production and isolation of 5-hydroxymethylfurfural from carbohydrates. ChemSusChem 2012, 5, 1388–1391. 10.1002/cssc.201200236. [DOI] [PubMed] [Google Scholar]
  35. Swift T. D.; Nguyen H.; Erdman Z.; Kruger J. S.; Nikolakis V.; Vlachos D. G. Tandem Lewis acid/Brønsted acid-catalyzed conversion of carbohydrates to 5-hydroxymethylfurfural using zeolite beta. J. Catal. 2016, 333, 149–161. 10.1016/j.jcat.2015.10.009. [DOI] [Google Scholar]
  36. Guo Q.; Ren L.; Alhassan S. M.; Tsapatsis M. Glucose isomerization in dioxane/water with Sn-β catalyst: improved catalyst stability and use for HMF production. Chem. Commun. 2019, 55, 14942–14945. 10.1039/C9CC07842H. [DOI] [PubMed] [Google Scholar]
  37. Fan C.; Guan H.; Zhang H.; Wang J.; Wang S.; Wang X. Conversion of fructose and glucose into 5-hydroxymethylfurfural catalyzed by a solid heteropolyacid salt. Biomass Bioenergy 2011, 35, 2659–2665. 10.1016/j.biombioe.2011.03.004. [DOI] [Google Scholar]
  38. Dai J.; Zhu L.; Tang D.; Fu X.; Tang J.; Guo X.; Hu C. Sulfonated polyaniline as a solid organocatalyst for dehydration of fructose into 5-hydroxymethylfurfural. Green Chem. 2017, 19, 1932–1939. 10.1039/C6GC03604J. [DOI] [Google Scholar]
  39. Du M.; Agrawal A. M.; Chakraborty S.; Garibay S. J.; Limvorapitux R.; Choi B.; Madrahimov S. T.; Nguyen S. T. Matching the activity of homogeneous sulfonic acids: the fructose-to-HMF conversion catalyzed by hierarchically porous sulfonic-acid-functionalized porous organic polymer (POP) catalysts. ACS Sustainable Chem. Eng. 2019, 7, 8126–8135. 10.1021/acssuschemeng.8b05720. [DOI] [Google Scholar]
  40. Qi X.; Watanabe M.; Aida T. M.; Smith R. L. Jr. Catalytical conversion of fructose and glucose into 5-hydroxymethylfurfural in hot compressed water by microwave heating. Catal. Commun. 2008, 9, 2244–2249. 10.1016/j.catcom.2008.04.025. [DOI] [Google Scholar]
  41. Svenningsen G. S.; Kumar R.; Wyman C. E.; Christopher P. Unifying mechanistic analysis of factors controlling selectivity in fructose dehydration to 5-hydroxymethylfurfural by homogeneous acid catalysts in aprotic solvents. ACS Catal. 2018, 8, 5591–5600. 10.1021/acscatal.8b01197. [DOI] [Google Scholar]
  42. Romo J. E.; Bollar N. V.; Zimmermann C. J.; Wettstein S. G. Conversion of sugars and biomass to furans using heterogeneous catalysts in biphasic solvent systems. ChemCatChem 2018, 10, 4805–4816. 10.1002/cctc.201800926. [DOI] [PMC free article] [PubMed] [Google Scholar]
  43. Pholjaroen B.; Li N.; Wang Z.; Wang A.; Zhang T. Dehydration of xylose to furfural over niobium phosphate catalyst in biphasic solvent system. J. Energy Chem. 2013, 22, 826–832. 10.1016/S2095-4956(14)60260-6. [DOI] [Google Scholar]
  44. Wrigstedt P.; Keskiväli J.; Repo T. Microwave-enhanced aqueous biphasic dehydration of carbohydrates to 5-hydroxymethylfurfural. RSC Adv. 2016, 6, 18973–18979. 10.1039/C5RA25564C. [DOI] [Google Scholar]
  45. He J.; Liu M.; Huang K.; Walker T. W.; Maravelias C. T.; Dumesic J. A.; Huber G. W. Production of levoglucosenone and 5-hydroxymethylfurfural from cellulose in polar aprotic solvent-water mixtures. Green Chem. 2017, 19, 3642–3653. 10.1039/C7GC01688C. [DOI] [Google Scholar]
  46. Chheda J. N.; Román-Leshkov Y.; Dumesic J. A. Production of 5-hydroxymethylfurfural and furfural by dehydration of biomass-derived mono- and poly-saccharides. Green Chem. 2007, 9, 342–350. 10.1039/B611568C. [DOI] [Google Scholar]
  47. De Souza R. L.; Yu H.; Rataboul F.; Essayem N. 5-Hydroxymethylfurfural (5-HMF) production from hexoses: limits of heterogeneous catalysis in hydrothermal conditions and potential of concentrated aqueous organic acids as reactive solvent system. Challenges 2012, 3, 212–232. 10.3390/challe3020212. [DOI] [Google Scholar]
  48. Zhang X.; Hewetson B. B.; Mosier N. S. Kinetics of maleic acid and aluminum chloride catalyzed dehydration and degradation of glucose. Energy Fuels 2015, 29, 2387–2393. 10.1021/ef502461s. [DOI] [Google Scholar]
  49. Zhang L.; Xi G.; Zhang J.; Yu H.; Wang X. Efficient catalytic system for the direct transformation of lignocellulosic biomass to furfural and 5-hydroxymethylfurfural. Bioresour. Technol. 2017, 224, 656–661. 10.1016/j.biortech.2016.11.097. [DOI] [PubMed] [Google Scholar]
  50. Mellmer M. A.; Sanpitakseree C.; Demir B.; Ma K.; Elliott W. A.; Bai P.; Johnson R. L.; Walker T. W.; Shanks B. H.; Rioux R. M.; Neurock M.; Dumesic J. A. Effects of chloride ions in acid-catalyzed biomass dehydration reactions in polar aprotic solvents. Nat. Commun. 2019, 10, 1132–1110. 10.1038/s41467-019-09090-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
  51. Zhang W.; Tao H.; Zhang B.; Ren J.; Lu G.; Wang Y. One-pot synthesis of carbonaceous monolith with surface sulfonic groups and its carbonization/activation. Carbon 2011, 49, 1811–1820. 10.1016/j.carbon.2010.12.050. [DOI] [Google Scholar]
  52. Dee S. J.; Bell A. T. A study of the acid-catalyzed hydrolysis of cellulose dissolved in ionic liquids and the factors influencing the dehydration of glucose and the formation of humins. ChemSusChem 2011, 4, 1166–1173. 10.1002/cssc.201000426. [DOI] [PubMed] [Google Scholar]
  53. Patil S. K. R.; Heltzel J.; Lund C. R. F. Comparison of structural features of humins formed catalytically from glucose, fructose, and 5-hydroxymethylfurfuraldehyde. Energy Fuels 2012, 26, 5281–5293. 10.1021/ef3007454. [DOI] [Google Scholar]
  54. Cheng Z.; Everhart J. L.; Tsilomelekis G.; Nikolakis V.; Saha B.; Vlachos D. G. Structural analysis of humins formed in the Brønsted acid catalyzed dehydration of fructose. Green Chem. 2018, 20, 997–1006. 10.1039/C7GC03054A. [DOI] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

ao0c05857_si_001.pdf (5.1MB, pdf)

Articles from ACS Omega are provided here courtesy of American Chemical Society

RESOURCES