Letter pubs.acs.org/journal/ascecg
One-Step Continuous Conversion of Fructose to 2,5Dihydroxymethylfuran and 2,5-Dimethylfuran Xiaomin Xiang,†,‡ Jinglei Cui,†,‡ Guoqiang Ding,§ Hongyan Zheng,§ Yulei Zhu,*,†,§ and Yongwang Li†,§ †
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, 27 South Taoyuan Road, Taiyuan 030001, People’s Republic of China ‡ University of Chinese Academy of Sciences, Beijing 100039, People’s Republic of China § Synfuels China Co., Ltd., Taiyuan 030032, People’s Republic of China S Supporting Information *
ABSTRACT: Selective conversion of fructose to fuels and fine chemicals is an important step for biomass utilization. In this paper, direct conversion of fructose to 2,5-dihydroxymethylfuran and 2,5dimethylfuran was first realized over combined HY zeolite and inexpensive hydrotalcite (HT)-Cu/ ZnO/Al2O3 in a fixed-bed reactor. The cooperative effect of HY zeolite and γ-butyrolactone solvent facilitated the dehydration of fructose into 5-hydroxymethylfurfural. By adjusting the hydrogenation temperature for HMF over HT-Cu/ZnO/Al2O3 catalyst, high yields of 2,5-dihydroxymethylfuran (48.2%) at 140 °C and 2,5-dimethylfuran (40.6%) at 240 °C were obtained, respectively.
KEYWORDS: HY zeolite, γ-Butyrolactone, HT-Cu/ZnO/Al2O3, 5-Hydroxymethylfurfural, Biomass
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INTRODUCTION Fossil resources depletion and environmental pollution are driving chemists to find strategies to make full use of renewable biomass to produce fuels and chemicals.1,2 5-(Hydroxymethyl)furfural (HMF), derived from the dehydration of carbohydrates,3,4 is one of top-valued platform compounds, which can be converted into a series of valuable chemicals5,6 such as 2,5dihydroxymethylfuran (DHMF) and 2,5-dimethylfuran (DMF). DHMF is the raw material for producing polymers, intermediates of drugs and crown ethers.7,8 DMF is considered as a promising fuel as it has high energy density (30 kJ cm−3) and octane number (RON = 119),9 and can also be converted to valuable benzene-based chemicals including p-xylene via Diels−Alder reactions.10 So far, the production of DHMF and DMF from carbohydrates contains two steps (Scheme 1):11 1. The dehydration of hexose (fructose) to HMF over different acid catalyst, such as ion-exchange resins, heteropolyacids, and Hform zeolites.12 2. The hydrogenation/hydrogenolysis of −C O and CO of HMF over metal catalyst, such as Ni-base or Ru-based catalyst,13,14 the main difficulty is to inhibit the hydrogenation of CC of HMF.7 The direct synthesis of DHMF or DMF from readily available carbohydrates (such as fructose) provides an alternative approach without separation of HMF. Many studies focused on improving the efficiencies of the single steps,2,4 while increasing the efficiencies of the direct conversion of fructose to DHMF or DMF is scarce. Especially, the controllable production of DHMF and DMF from fructose © 2016 American Chemical Society
still remains a big challenge. Thananatthanachon and Rauchfuss have investigated the one-pot two steps production of DMF from fructose over combined HCOOH and Pd/C catalysts and a yield of 51% for DMF was obtained in the batch reactor.15 Yang and co-workers reported catalytic conversion of fructose by using a combination of Amberlyst-15 and hydrophobic Ru/ SiO2 in a water/cyclohexane biphasic system, and the main product was tetrahydro-2,5-furandimethanol with a yield of 35%.16 However, a few drawbacks were inevitable by using the batch reactor. In a batch reactor, hexose molecules would readily contact the hydrogenation catalyst and be converted into mannitol and sorbitol, which cannot be converted to HMF. Additionally, the contact time is longer in the batch reactor compared with that in the continuous reactor, which would promote drastically the side reactions between fructose, fructose dehydration intermediates and DHMF.17 Above drawbacks would result in a complexity in the product distribution and reduce the yield of the overall process. Therefore, it is desirable to develop a more efficient process to produce DHMF and DMF directly from fructose with improving overall yield under mild reaction conditions. Herein, a new continuous process was designed for the synthesis of DHMF and DMF via the direct conversion of fructose over a combined catalyst of HY zeolite and HT-Cu/ Received: June 21, 2016 Revised: August 8, 2016 Published: August 22, 2016 4506
DOI: 10.1021/acssuschemeng.6b01411 ACS Sustainable Chem. Eng. 2016, 4, 4506−4510
Letter
ACS Sustainable Chemistry & Engineering Scheme 1. Conversion of Biomass to DHMF and DMF
Table 1. Dehydration of Fructose to HMFa yield (%) entry
catalysts
solvent
fructose con. (%)
HMF
FAL
LA
1 2 3 4 5b 6b 7b
HY Hβ H-mordenite HZSM-5 HY HY HY
GBL−water GBL−water GBL−water GBL−water water ethanol−water 1,4-dioxane−water
100 100 100 100 83.0 98.7 88.7
53.2 2.9 16.2 5.7 20.0 34.1 29.2
10.6 45.0 31.3 25.6 trace trace trace
0.3 5.1 1.6 8.9 0.2 1.9 1.9
Reaction conditions: 140 °C, WHSV (for fructose) = 0.02 h−1, H2 = 0.1 MPa, 15 mL/min, 4 g zeolite catalyst, fructose concentration = 3 wt %, water content in water−organic solvent mixture = 15 wt %. bH2 = 2 MPa, 300 mL/min. FAL: furfural. LA: levulinic acid.
a
ZnO/Al2O3 in a fix-bed reactor. In the solvent of γbutyrolactone (GBL)/water, HY zeolite catalyzed the dehydration of fructose to HMF effectively, and HT-Cu/ZnO/ Al2O3 catalyzed the hydrogenation and hydrogenolysis of the produced HMF to DHMF and DMF. The yield of DHMF and DMF can be simply tuning the hydrogenation temperature for HMF. High yields of DHMF (48.2%) at 140 °C and DMF (40.6%) at 240 °C were obtained over HT-Cu/ZnO/Al2O3 catalyst, respectively.
climbed up and then decreased with increasing the water content. The HMF yield reached a high level when the water content was 15%. Table 2. Effects of Water Content and Temperature on the Dehydration of Fructosea yield (%)
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entry T (°C)
RESULTS AND DISCUSSION Zeolites are excellent catalysts in the dehydration of sugars because of their high hydrothermal stability and shapeselectivity.1,18,19 Therefore, the conversion of fructose into HMF over various zeolites (HY, H-mordenite, HZSM-5 and Hβ) was studied in a fixed-bed reactor (Table 1, entries 1−4). The results showed that HY zeolite was beneficial to the formation of HMF, and other zeolites made for the formation of furfural. Our previous work has shown that the pore structure of Hβ and GBL solvent promoted the selective C−C bond cleavage of acyclic hexoses (fructose) into pentoses and the subsequent dehydration of pentoses into furfural. Meanwhile, HY zeolite was low active in the formation of furfural and facilitated the dehydration of fructose into HMF due to it owns more acid sites and unique pore structure (yield 53.2%).20 In the dehydration of sugars, solvent is another important factor;11,18 we have studied the effect of solvent on dehydration of fructose to HMF. The yield of HMF was low (∼20%) in water (Table 1, entry 5); this is because the catalytic efficiency of acid is low and HMF easily degrades to acids and humins in the presence of water and acid catalyst.16 Therefore, ethanol, 1, 4-dioxane and GBL were selected as the solvent (Table 1, entries 1,6,7) for the dehydration of fructose to HMF. It was observed that the HMF yield increased in these organic agentwater solvents. Especially, the highest yield of HMF was obtained in GBL-water because the HMF degradation was suppressed and the acid catalytic efficiency was promoted in GBL−water solvent.20 However, fructose is hardly miscible with organic solvents but easily dissolved in water, so water is required for the dissolution of fructose. Hence, the effect of water content in the GBL−water solvent on the dehydration reaction was studied (Table 2, entries 1−5). The HMF yield
1 2 3 4 5 6 7 8
water content (wt %)
fructose con. (%)
HMF
FAL
LA
10 15 20 30 40 15 15 15
100 100 100 100 100 71.0 95.0 100
45.4 53.2 45.7 38.7 30.2 20.0 28.1 35.5
8.3 10.6 8.8 7.6 7.4 3.1 7.6 11.9
0.2 0.3 0.6 1.1 1.6 trace trace 0.6
140 140 140 140 140 120 130 150
Reaction conditions: WHSV (for fructose) = 0.02 h−1, H2 = 15 mL/ min, 0.1 MPa, 4 g zeolite catalyst, fructose concentration for each run = 3 wt %. FAL: furfural. LA: levulinic acid.
a
The effect of reaction temperature was studied (Table 2, entries 2,6−8), and the suitable temperature for the generation of HMF is 140 °C. The influence of fructose WHSV on the dehydration of fructose over HY zeolite catalyst was also studied (Table 3). A decrease in fructose conversion occurred Table 3. Effect of Fructose WHSV on the Dehydration of Fructosea yield (%) −1
fructose WHSV (h )
fructose con. (%)
HMF
FAL
LA
0.015 0.020 0.025 0.030
100 100 100 99.3
43.8 53.2 45.2 44.7
10.6 10.6 8.1 8.8
0.6 0.3 0.3 0.2
Reaction conditions: 140 °C, H2 = 0.1 MPa,15 mL/min, 4 g HY zeolite catalyst, fructose concentration for each run = 3 wt %, water content in water−organic solvent mixture = 15 wt %. FAL: furfural. LA: levulinic acid. a
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DOI: 10.1021/acssuschemeng.6b01411 ACS Sustainable Chem. Eng. 2016, 4, 4506−4510
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ACS Sustainable Chemistry & Engineering
Table 4. Conversion of Fructose to DHMF and DMFa
when WHSV is more than 0.02 h−1, whereas the yield of HMF increased and then declined with increasing WHSV. Higher yield of HMF was obtained when the WHSV was 0.02 h−1. As illustrated in Figure S1, the fructose conversion and HMF yield did not present any distinct loss within 120 h time-on-stream at 140 °C, indicating HY zeolite catalyst exhibited better stability. Fructose can be efficiently converted to HMF over HY zeolite, so it is necessary to choose a suitable metal catalyst for the hydrogenation of formed HMF to DHMF and DMF. Cubased catalysts are one of the best materials for selective hydrogenation for their high reactivity to the selective hydrogenation of CO and CO bonds and relatively low reactivity to that of CC and CC bonds.21,22 In addition, Cu-based catalyst is more inexpensive than Ru and Ni catalysts. Therefore, we prepared conventional CuO/ZnO/Al2O3 catalyst and hydrotalcite (HT)-CuO/ZnO/Al2O3 catalyst (Determined by XRD in Figure S3) for the hydrogenation of produced HMF (Figure 1).23,24 As shown in Figure S2, DHMF yield was higher
Reaction conditions: WHSV (for fructose) = 0.02 h−1, H2 = 15 mL/ min, 0.1 MPa, 4 g HY zeolite and 5 g HT CuO/ZnO/Al2O3 catalysts; fructose concentration = 3 wt %; water concentration = 15 wt %, GBL concentration = 82 wt %. The reaction temperature for the fructose dehydration over HY zeolite was 140 °C. a
which the yield reached up to 48.2%. Moreover, a decrease in DHMF yield at a higher temperature was related to the formation of DMF. At 240 °C, DHMF was completely converted, and the DMF yield reached 40.6%. To our best of knowledge, direct conversion of fructose to DHMF in the fixed bed reactor was realized for the first time. Additionally, the method of packing of HY zeolite and HTCu/ZnO/Al2O3 significantly affected product yield. Hence, we studied the effect of mechanically mixed HY zeolite and HT Cu/ZnO/Al 2 O 3 (Figure S5, Table S2). Fructose was completely transformed, whereas DHMF and DMF were undetected, and sorbitol yield was lower than 0.1% within 120− 160 °C, From 180 to 240 °C, we only detected DMF and its yield was lower than 6.7%. We speculated the main product was humins and coke. Above results showed that mechanical mixing catalysts were unfit for the synthesis of DHMF and DMF from fructose directly, and the method of packing of the upper with HY and the bottom with HT-Cu/ZnO/Al2O3 was suitable for direct conversion of fructose to DHMF and DMF. The stability for combined HY zeolite and HT-Cu/ZnO/ Al2O3 was further studied. As illustrated in Figure 2, the catalysts did not present any distinct loss in the activity within 100 h time-on-stream at 140 °C for DHMF formation and at 240 °C for DMF formation. Concurrently, the yield of both did not show obvious fluctuation during the complete test, indicating that the catalyst exhibits better stability.
Figure 1. Direct conversion of fructose to DHMF and DMF in a fixbed reactor.
over HT-Cu/ZnO/Al2O3 (48.2%) than that over conventional Cu/ZnO/Al2O3 (32.3%) at 140 °C. As shown in Table S1, HTCu/ZnO/Al2O3 catalyst exhibited the larger BET surface area (73.6 m2 g−1) and the better copper dispersion (DCu) (18.9%). In addition, the surface acidic properties of HT-Cu/ZnO/Al2O3 catalyst are similar to conventional Cu/ZnO/Al2O3 (Figure S4). Therefore, we suggest that Cu/ZnO/Al2O3 catalyst prepared from hydrotalcite precursor can promote the dispersion of copper and improve its hydrogenation efficiency.24,25 As shown in Table 4, DMF production from HMF hydrogenation is composed of two main steps: the hydrogenation of the aldehyde group to DHMF and the subsequent hydrogenolysis of hydroxymethyl groups of DHMF. At low temperature, Cu-metal of HT-Cu/ZnO/Al2O3 catalyst adsorbed aldehyde and promoted the hydrogenation of the CO bonds of HFM to DHMF, but was hardly active for the hydrogenolysis of the CO bonds. Contrarily, at high temperature, surface metallic Cu sites and acid sites of HTCu/ZnO/Al2O3 catalysts promoted the hydrogenolysis of the CO bonds (Figure S4).7 It was discovered that the best reaction temperature for DHMF formation was 140 °C, at
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CONCLUSIONS
We developed a one-step efficient approach to convert fructose directly to DHMF or DMF by tandem dehydration and hydrogenation using HY zeolite and HT-Cu/ZnO/Al2O3 catalyst in a fixed-bed reactor with GBL−water as the solvent. HY zeolite is found to show high activity and selectivity to the formation of HMF owing to its higher acidity and unique pore structure. In addition, high yields of DHMF (48.2%) and DMF (40.6%) were obtained by simply tuning the reaction temperature over HT-Cu/ZnO/Al2O3 catalyst. 4508
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ACS Sustainable Chemistry & Engineering
(4) Teong, S. P.; Yi, G.; Zhang, Y. Hydroxymethylfurfural production from bioresources: past, present and future. Green Chem. 2014, 16, 2015. (5) 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 2,5furandicarboxylic acid. J. Catal. 2013, 299, 316−320. (6) Chatterjee, M.; Ishizaka, T.; Kawanami, H. Selective hydrogenation of 5-hydroxymethylfurfural to 2,5-bis-(hydroxymethyl)furan using Pt/MCM-41 in an aqueous medium: a simple approach. Green Chem. 2014, 16, 4734−4739. (7) Zhu, Y.; Kong, X.; Zheng, H.; Ding, G.; Zhu, Y.; Li, Y.-W. Efficient synthesis of 2,5-dihydroxymethylfuran and 2,5-dimethylfuran from 5-hydroxymethylfurfural using mineral-derived Cu catalysts as versatile catalysts. Catal. Sci. Technol. 2015, 5, 4208−4217. (8) Hao, W.; Li, W.; Tang, X.; Zeng, X.; Sun, Y.; Liu, S.; Lin, L. Catalytic transfer hydrogenation of biomass-derived 5-hydroxymethyl furfural to the building block 2,5-bishydroxymethyl furan. Green Chem. 2016, 18, 1080−1088. (9) Roman-Leshkov, Y.; Barrett, C. J.; Liu, Z. Y.; Dumesic, J. A. Production of dimethylfuran for liquid fuels from biomass-derived carbohydrates. Nature 2007, 447, 982−5. (10) Do, P. T. M.; McAtee, J. R.; Watson, D. A.; Lobo, R. F. Elucidation of Diels-Alder reaction network of 2,5-dimethylfuran and ethylene on HY zeolite catalyst. ACS Catal. 2013, 3, 41−46. (11) van Putten, R. J.; van der Waal, J. C.; de Jong, E.; Rasrendra, C. B.; Heeres, H. J.; de Vries, J. G. Hydroxymethylfurfural, a versatile platform chemical made from renewable resources. Chem. Rev. 2013, 113, 1499−597. (12) Caes, B. R.; Teixeira, R. E.; Knapp, K. G.; Raines, R. T. Biomass to furanics: renewable routes to chemicals and fuels. ACS Sustainable Chem. Eng. 2015, 3, 2591−2605. (13) Zu, Y.; Yang, P.; Wang, J.; Liu, X.; Ren, J.; Lu, G.; Wang, Y. Efficient production of the liquid fuel 2,5-dimethylfuran from 5hydroxymethylfurfural over Ru/Co3O4 catalyst. Appl. Catal., B 2014, 146, 244−248. (14) Yu, L.; He, L.; Chen, J.; Zheng, J.; Ye, L.; Lin, H.; Yuan, Y. Robust and recyclable nonprecious bimetallic nanoparticles on carbon nanotubes for the hydrogenation and hydrogenolysis of 5-hydroxymethylfurfural. ChemCatChem 2015, 7, 1701−1707. (15) Thananatthanachon, T.; Rauchfuss, T. B. Efficient production of the liquid fuel 2, 5-dimethylfuran from fructose using formic acid as a reagent. Angew. Chem. 2010, 122, 6766−6768. (16) Yang, Y.; Du, Z.; Ma, J.; Lu, F.; Zhang, J.; Xu, J. Biphasic catalytic conversion of fructose by continuous hydrogenation of HMF over a hydrophobic ruthenium catalyst. ChemSusChem 2014, 7, 1352− 6. (17) Cui, J.; Tan, J.; Cui, X.; Zhu, Y.; Deng, T.; Ding, G.; Li, Y. Conversion of xylose to furfuryl alcohol and 2-methylfuran in a continuous fixed-bed reactor. ChemSusChem 2016, 9, 1−5. (18) Wang, T.; Nolte, M. W.; Shanks, B. H. Catalytic dehydration of C6 carbohydrates for the production of hydroxymethylfurfural (HMF) as a versatile platform chemical. Green Chem. 2014, 16, 548−572. (19) Abou-Yousef, H.; Hassan, E. B. A novel approach to enhance the activity of H-form zeolite catalyst for production of hydroxymethylfurfural from cellulose. J. Ind. Eng. Chem. 2014, 20, 1952− 1957. (20) Cui, J.; Tan, J.; Deng, T.; Cui, X.; Zhu, Y.; Li, Y. Conversion of carbohydrates to furfural via selective cleavage of the carbon-carbon bond: the cooperative effects of zeolite and solvent. Green Chem. 2016, 18, 1619−1624. (21) Dong, F.; Zhu, Y.; Zheng, H.; Zhu, Y.; Li, X.; Li, Y. Cr-free Cucatalysts for the selective hydrogenation of biomass-derived furfural to 2-methylfuran: The synergistic effect of metal and acid sites. J. Mol. Catal. A: Chem. 2015, 398, 140−148. (22) Zhu, Y.; Kong, X.; Zheng, H.; Ding, G.; Zhu, Y.; Li, Y.-W. Efficient synthesis of 2,5-dihydroxymethylfuran and 2,5-dimethylfuran from 5-hydroxymethylfurfural using mineral-derived Cu catalysts as versatile catalysts. Catal. Sci. Technol. 2015, 5, 4208−4217.
Figure 2. Long-term stability of catalysts. Reaction conditions: 4 g HY zeolite +5 g HT Cu/ZnO/Al2O3, dehydration temperature = 140 °C, WHSV (for fructose) = 0.02 h−1, H2 = 15 mL/min, 0.1 MPa; fructose concentration = 3 wt %; water concentration = 15 wt %; GBL concentration = 82 wt %. Hydrogenation temperature: a, 140 °C; b, 240 °C.
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ASSOCIATED CONTENT
S Supporting Information *
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acssuschemeng.6b01411. Experimental section: 1 Materials; 2 Catalyst preparation and characterization; 3 Catalytic test and analysis method. Figure S1 shows the long-term stability of HY zeolite in the dehydration of fructose. Figure S2 shows the yield of DMHF on different catalysts. Figure S3 shows X-ray diffraction patterns of the HT-CuO/ZnO/ Al2O3. Figure S4 shows NH3-TPD of catalyst: a, Conventional Cu/ZnO/Al2O3; b, HT- CuO/ZnO/ Al2O3. Figure S5 shows the conversion of fructose on mixed catalysts in a fix-bed reactor. The physicochemical properties of the Cu-catalysts are shown in Table S1. Table S2 shows the conversion of fructose on mixed catalysts (PDF).
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AUTHOR INFORMATION
Corresponding Author
*Y. Zhu. E-mail:
[email protected]. Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS The authors gratefully acknowledge the financial support of the Major State Basic Research Development Program of China (973 Program) (no. 2012CB215305).
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REFERENCES
(1) Chatterjee, C.; Pong, F.; Sen, A. Chemical conversion pathways for carbohydrates. Green Chem. 2015, 17, 40−71. (2) Jain, A.; Shore, A. M.; Jonnalagadda, S. C.; Ramanujachary, K. V.; Mugweru, A. Conversion of fructose, glucose and sucrose to 5hydroxymethyl-2-furfural over mesoporous zirconium phosphate catalyst. Appl. Catal., A 2015, 489, 72−76. (3) Chen, J.; Li, K.; Chen, L.; Liu, R.; Huang, X.; Ye, D. Conversion of fructose into 5-hydroxymethylfurfural catalyzed by recyclable sulfonic acid-functionalized metal-organic frameworks. Green Chem. 2014, 16, 2490−2499. 4509
DOI: 10.1021/acssuschemeng.6b01411 ACS Sustainable Chem. Eng. 2016, 4, 4506−4510
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ACS Sustainable Chemistry & Engineering (23) Zhu, Y. L.; Yang, J.; Dong, G. Q.; Zheng, H. Y.; Zhang, H. H.; Xiang, H. W.; Li, Y. W. An environmentally benign route to γbutyrolactone through the coupling of hydrogenation and dehydrogenation. Appl. Catal., B 2005, 57, 183−190. (24) Gao, P.; Li, F.; Zhan, H.; Zhao, N.; Xiao, F.; Wei, W.; Zhong, L.; Wang, H.; Sun, Y. Influence of Zr on the performance of Cu/Zn/Al/ Zr catalysts via hydrotalcite-like precursors for CO2 hydrogenation to methanol. J. Catal. 2013, 298, 51−60. (25) Wang, Y.; Zhou, M.; Wang, T.; Xiao, G. Conversion of furfural to cyclopentanol on Cu/Zn/Al catalysts derived from hydrotalcite-like materials. Catal. Lett. 2015, 145, 1557−1565.
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