S1 Supporting Information Efficient productions of 5-hydroxymethylfurfural and alkyl levulinate from biomass carbohydrate using ionic liquid-based polyoxometalate salts Jinzhu Chen,* a Guoying Zhao a and Limin Chen b a CAS Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 516, PR China b Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, College of Environment and Energy, South China University of Technology, Guangzhou 516, PR China * Corresponding author. Tel./Fax: (+86)--3722-33. E-mail address: chenjz@ms.giec.ac.cn (J. Chen) Keywords: Biomass carbohydrate, Ethyl levulinate, 5-Hydroxymethylfurfural, ionic liquid-based polyoxometalate, Solid acid
S2 1. Experimental 1.1. Procedure for the catalyst preparation The ILs 3 7 were prepared according to literature procedure with slight modifications (Scheme 2). In a typical synthetic procedure of 3, to a solution of TMEDA (2.9 g, 25 mmol) in ethanol (5 ml) was portion-wise added 1,3-propanesulfonate (6.1 g, 5 mmol) within 15 minutes. The mixture was then stirred under a nitrogen atmosphere for 2 hours at C. The reaction system was cooled to room temperature; the white precipitate thus formed was isolated by filtration, and washed with ethyl acetate (3 5 ml) then dried under vacuum. IL 3 was obtained as white solid with the yield of 91%. 3: 1 H NMR ( MHz, D 2 ): δ = 3.96 (s, 4H), 3.59 (m, 4H), 3.24 (s, 12H), 2.98 (t, 4H, J = 8. Hz), 2.27 (m, 4H). [1] Preparation of 4: 4 was prepared by refluxing 4,4 -bipyridine (.78 g, 5. mmol) with 1,3-propanesultone (1.5 g, 12 mmol) for 15 minutes at 1 C without solvent under a nitrogen atmosphere. To the resulting semi-solid mixture, dimethyl sulfoxide (5 ml) was injected and heated at 1 C while being stirred continuously for 3 hours. After cooling, the white precipitate was filtered and washed several times with methanol, dried over filter papers to give 77% yield of the desired product of 4, brown solid. 4: 1 H NMR ( MHz, D 2 ): δ = 9.12 (d, 4H, J = 8. Hz), 8.53 (d, 4H, J = 8. Hz), 4.86 (t, 4H, J = 8. Hz), 2.99 (t, 4H, J = 6. Hz), 2.5 (m, 4H). [2] Preparation of sodium salt of 5: Sodium ethoxide (1.7 g, 25 mmol) and 2-methylimidazole (2.1 g, 25 mmol) were mixed in ethanol (5 ml) under a nitrogen atmosphere for 2 hours at room temperature. After that, an excess of 1,3-propanesultone (7.7 g, 63 mmol) was added to the mixture, and this solution was stirred for 2 hours at room temperature. The product was washed twice with ethanol, and then the precipitate was recovered and dried in a vacuum at C to give 74% yield of the desired product of sodium salt of 5, white solid. [Na + 5 ]: 1 H NMR ( MHz, D 2 ): δ = 7.39 (s, 2H), 4.22 (t, 4H, J = 8. Hz), 2.89 (t, 4H, J = 8. Hz), 2.58 (s, 3H), 2.19 (m, 4H). [3] Preparation of 6: 1-Methylimidazole (2.1 g, 25 mmol) and 1,3-propanesulfone (6.1 g, 25 mmol) were dissolved in toluene (5 ml) and stirred for 24 hours at 5 C under a nitrogen atmosphere. A white precipitate formed which was filtered, washed with diethyl ether three times, and then dried in a vacuum at C to give 89% yield of the desired product of 6, white solid. 6: 1 H NMR ( MHz, D 2 ): δ = 8.71 (s, 1H), 7.48 (s, 1H), 7.41 (s, 1H), 4.32 (t, 2H, J = 8. Hz), 3.85 (s, 3H), 2.88 (t, 2H, J = 8. Hz), 2.27 (m, 2H). [4] Preparation of 7: Triphenylphosphine (6.6 g, 25 mmol) and 1,3-propanesultone (6.1 g, 25 mol) were combined in toluene (5 ml) and brought to reflux. vernight, a white precipitate forms which is isolated by filtration and dried in a vacuum at C to give % yield of the desired product of 7, white solid. 7: 1 H NMR ( MHz, D 2 ): δ = 7. 7.59 (m, 15H), 3.41 (m, 2H), 2.97 (t, 2H, J = 8. Hz), 2.5 (m, 2H). [5] 2. Results and Discussion 2.1. FTIR comparison of IL-PMs Scheme 2 shows the structures of IL-PMs in this research. Generally, the ILs
S3 3 7 were prepared according to literature methods; whereas, the IL-PMs used in this research were prepared by the treatment of propane sulfonate-functionalized ILs 3 7 with HPA in water. a 1482 1228 1155 598 513 b c 1481 1 896 141 981 811 1227 1153 145 882 974 924 795 2 529 1481 1226 1153 164 958 885 786 499 1 1 1 1 Wavenumbers / cm -1 Figure S1. FT-IR of (a) [3 2H] 3 [PW 12 ] 2, (b) [3 2H] 2 [SiW 12 ], and (c) [3 2H] 3 [PMo 12 ] 2. FT-IR spectra of [3 2H] 3 [PW 12 ] 2, [3 2H] 2 [SiW 12 ], and [3 2H] 3 [PMo 12 ] 2 were compared in Figure S1. The FT-IR spectra of 3-PM hybrid samples clearly showed the presence of both the [3 2H] 2+ and heteropolyanion species. In the case of [3 2H] 3 [PW 12 ] 2, the band at 1482 cm 1 was attributed to the asymmetric deformation vibration of the C H bond in CH 3 of 3 (Figure S1a). [6] In addition, two bands at 1228 and 1155 cm 1 were assigned to S= stretching vibrations, indicating the presence of a sulfonic group. [7] The characteristic bands of P a vibration in [3 2H] 3 [PW 12 ] 2 is visible at 1 and 141 cm 1. [8,9] While, the vibration of W= d stretching appears at 981 cm 1. Vibrations associated with W b W and W c W, are observed at 896 and 811 cm 1, respectively (Figure S1a). For FT-IR spectra of [3 2H] 2 [SiW 12 ], the bands at 145 and 924 cm 1 are assigned to stretching vibration of Si a, while the peak at 974 cm 1 can be indexed to terminal bands vibration of W= d. Vibrations associated with W b W and W c W, are observed at 882 and 795 cm 1, respectively (Figure S1b). [8,9] In the case of [3 2H] 3 [PMo 12 ] 2, the peaks at 164 and 958 cm 1 can be assigned to stretching vibration of P a and terminal bands vibration of Mo= d, respectively, while the bands at 786 cm 1 and 885 cm 1 are associated with stretching vibration of Mo c Mo and Mo b Mo, respectively (Figure S1c). [8,9] The above FT-IR spectra analysis thus confirmed the structure of 3-PM hybrids. 2.2. The influence of solvent on fructose conversion The influence of solvent on fructose conversion to HMF was also investigated under similar reaction conditions, different aprotic (DMS, DMF and THF), and protic (alcohols) solvents were employed with [3 2H] 3 [PW 12 ] 2 as catalyst (Table
S4 S1, Runs 1 6). The yield of HMF with DMS, achieving 9% with a full fructose conversion (Table S1, Run 1), was much higher than that with the other solvents. n the contrary, the conversion of fructose dehydration with iso-butanol as slovent is remarkably inferior, producing HMF yield only of 1%. Furthermore, the catalyst [3 2H] 3 [PW 12 ] 2 is insoluble in the solvents described in table S1, precipitates at the end of the reaction and can be easily recycled. Table S1. Conversion of fructose into HMF in various solvents and the influence of the solvent volume a Run Solvent Volume [ml] Conversion [%] Yield [%] 1 DMS 2 >99 9 2 DMF 2 89 49 3 THF 2 99 25 4 iso-propanol 2 89 35 5 sec-butanol 2 74 16 6 iso-butanol 2 68 1 7 DMS 1 >99 84 8 DMS 3 99 89 9 DMS 4 99 88 1 DMS 5 98 86 a Reaction conditions: fructose (5 mg,.28 mmol), [3 2H] 3 [PW 12 ] 2, (25 mg, 2.5 mol%), 1 C,.5 h. 2.3. The influence of fructose concentration on its conversion It has been pointed out that the carbohydrate concentration affected the HMF yield in acidic medium. For higher fructose concentrations, the HMF yield decreases due to the formation of larger amounts of humins. Consequently, the fructose dehydration reaction with [3 2H] 3 [PW 12 ] 2 as solid acid catalyst was performed by changing the amount of DMS to investigate the effect of the fructose concentrations on HMF yields. When using 1 ml of DMS, the yield of HMF was 84% which was lower than that obtained with 2 ml of DMS with HMF yield of 9% at the same reaction time point (Table 2, Runs 1 and 7). Furthermore, during the reaction process, the reaction system quickly turned dark brown in 1 ml of DMS. This indicated that HMF readily further polymerized to form oligomers under the relatively high concentration. By further increasing the DMS volume to 3 ml, 4 ml and 5 ml, HMF yields, however, decreased with fructose concentration. References [1] D. Fang, J.M. Yang, C.M. Jiao, ACS Catalysis 1 (11) 42 47. [2] S. Bhandari, M. Deepa, S. Pahal, A.G. Joshi, A.K. Srivastava, R. Kant, ChemSusChem 3 (1) 97 15. [3] Y. Masahiro, H. hno, Ionics 8 (2) 267 271. [4] Y. Leng, J. Wang, D.R. Zhu, X.Q. Ren, H.Q. Ge, L. Shen, Angewandte Chemie
S5 121 (8) 174 177; Angewandte Chemie International Edition 48 (8) 168 171. [5] A.C. Cole, J.L. Jensen, I. Ntai, K.L.T. Tran, K.J. Weaver, D.C. Forbes, J.H. Davis, Jr., Journal of the American Chemical Society, 124 (2) 5962 5963. [6] G. Socrates, Infrared and Raman Characteristic Group Frequencies, Tables and Charts, 3rd ed., J. Wiley & Sons, New York, 1. [7] Z.H. Zhang, K. Dong, Z.B. Zhao, ChemSusChem 4 (11) 112 118. [8] D.S. Pito, I. Matos, I.M. Fonseca, A.M. Ramos, J. Vital, J.E. Castanheiro, Applied Catalysis A: General 373 (1) 1 146 [9] F. Chai, F.H. Cao, F.Y. Zhai, Y. Chen, X.H. Wang, Z.M. Su, Advanced Synthesis & Catalysis 349 (7) 157 165. Figure S2. 1 H and 13 C{ 1 H} NMR analysis. 1. 1.7 1.7 2.36 9.34 9.33 9.32 7.41 7. 6.55 6.55 4.7 4.57 11.5 1.5 9.5 8.5 7.5 6.5 5.5 ppm 4.5 3.5 2.5 1.5.5 Figure S2-1. 1 H NMR of 5-hydroxymethylfurfural in D 2.
S6 1.47 161.32 151.79 126.84 11.96 56.1 19 17 15 13 11 ppm 9 7 5 3 1 Figure S2-2. 13 C { 1 H} NMR of 5-hydroxymethylfurfural in D 2. 2. 2.7 2.6 3.4 3.8 4.14 4.13 4.11 4.9 2.76 2.74 2.72 2.57 2.56 2.54 2.18 1.26 1.24 1.22 7.5 7. 6.5 6. 5.5 5. 4.5 4. ppm 3.5 3. 2.5 2. 1.5 1..5. Figure S2-3. 1 H NMR of ethyl levulinate in CDCl 3.
S7 6.7 172.73 77.32 77. 77. 76.68. 37.91 29.85 27.98 14.12 -.5 21 19 17 15 13 11 ppm 9 7 5 3 1 Figure S2-4. 13 C { 1 H} NMR of ethyl levulinate in CDCl 3. 1.97 2. 2. 2.94 2.2 2. 3. 4.7 4.5 4.3 2.74 2.73 2.71 2.56 2.55 2.53 2.17 1.58 1.54 1.36 1.3.92.91.89 7.5 7. 6.5 6. 5.5 5. 4.5 4. 3.5 ppm 3. 2.5 2. 1.5 1..5. Figure S2-5. 1 H NMR of n-butyl levulinate in CDCl 3.
S8 6.69 172.82 77.37 77.25 77.5 76.73 64.53 37.95 27.99 19.8 13.67 -.3 21 19 17 15 13 11 ppm 9 7 5 3 1 Figure S2-6. 13 C { 1 H} NMR of n-butyl levulinate in CDCl 3. - 3 S N N S - 3 2 Figure S2-7. 1 H NMR of 3 in D 2.
S9 4. 4.1 4.5 4.1 4.3 9.13 9.11 8.54 8.52 4.88 4.86 4.84 3.1 2.99 2.98 2.53 2.52 2.5 2.48 2.46 N N Solvent - 3 S S 3-9.5 9. 8.5 8. 7.5 7. 6.5 6. 5.5 ppm 5. 4.5 4. 3.5 3. 2.5 2. 1.5 1. Figure S2-8. 1 H NMR of 4 in D 2 2. 4.2 4.4 3.2 4.7 7.39 4.24 4.22 4. 2.91 2.89 2.87 2.58 2.23 2.21 2.19 2.18 2.16 N N - 3 S - S Na 3 Solvent 7.8 7.2 6.6 6. 5.4 4.8 ppm 4.2 3.6 3. 2.4 1.8 Figure S2-9. 1 H NMR of sodium salt of 5 in D 2
S1 1. 1.1.98 2.1 3.1 2.3 2.8 8.71 7.48 7.41 4.34 4.32 4.3 3.85 2.9 2.88 2.86 2.31 2.29 2.27 2.26 2.24 N N S 3 - Solvent 9.5 9. 8.5 8. 7.5 7. 6.5 6. 5.5 ppm 5. 4.5 4. 3.5 3. 2.5 2. 1.5 Figure S2-1. 1 H NMR of 6 in D 2 15.3 2.1 2.1 1.99 7. 7.78 7.76 7.7 7.68 7.65 7.64 7.63 7.62 7.61 7.59 3.45 3.43 3.41 3.41 3.39 3.37 2.98 2.96 2.1 2.8 2.6 2.4 2.2 2. P S 3 - Solvent 9. 8.5 8. 7.5 7. 6.5 6. 5.5 5. ppm 4.5 4. 3.5 3. 2.5 2. 1.5 1. Figure S2-11. 1 H NMR of 7 in D 2
S11 Figure S3. FT-IR analysis 1 transmmittance / % 9 7 3377 1518 1197 116 167 35 3 25 15 1 5 Figure S3-1. FT-IR of 5-hydroxymethylfurfural on KBr Pellet. FT-IR (KBr, cm -1 ): ν = 3377 ( H), 167 (C=). 1 transmmittance / % 9 7 2987 1413 1364 1155 1726 5 35 3 25 15 1 5 Figure S3-2. FT-IR of ethyl levulinate on KBr Pellet. FT-IR (KBr, cm -1 ): ν = 1726 (C=).
S12 1 transmmittance / % 9 7 5 2959 1469 1358 1163 1726 35 3 25 15 1 5 Figure S3-3. FT-IR of butyl levulinate on KBr Pellet. FT-IR (KBr, cm -1 ): ν = 1726 (C=). 1 1482 12281155141 896 1 981 811 1 1 1 1 1 Wavenumber/cm -1 Figure S3-4. FT-IR of [3 2H] 3 [PW 12 ] 2 on KBr Pellet. FT-IR (KBr, cm -1 ): ν = 1482 (C H in CH 3 ), 1228, 1155 (S=), 1, 141 (P a ), 981 (W= d ), 896 (W b W), 811 (W c W).
S13 1 1481 1153 1227 145 882 974 924 795 1 1 1 1 1 Figure S3-5. FT-IR of [3 2H] 2 [SiW 12 ] on KBr Pellet. FT-IR (KBr, cm -1 ): ν = 1481 (C H in CH 3 ), 1227, 1153 (S=), 145, 924 (Si a ), 974 (W= d ), 882 (W b W), 795 (W c W). 1 1481 1226 1153 885 164 958 786 1 1 1 1 1 Figure S3-6. FT-IR of [3 2H] 3 [PMo 12 ] 2 on KBr Pellet. FT-IR (KBr, cm -1 ): ν = 1481 (C H in CH 3 ), 1226, 1153 (S=), 164 (P a ), 958 (Mo= d ), 885 (W b W), 786 (W c W).
S14 1 163 154 1458 1228 1155 141 1 896 981 811 1 1 1 1 1 Figure S3-7. FT-IR of [4 2H] 3 [PW 12 ] 2 on KBr Pellet. FT-IR (KBr, cm -1 ): ν = 163 (C=N, C N), 154, 1458 (C=C), 1228, 1155 (S=), 1, 141 (P a ), 981 (W= d ), 896 (W b W), 811 (W c W). 1 154 1458 163 1227 1153 145 882 974 924 795 1 1 1 1 1 Wavenunmber / cm -1 Figure S3-8. FT-IR of [4 2H] 2 [SiW 12 ] on KBr Pellet. FT-IR (KBr, cm -1 ): ν = 163 (C=N, C N), 154, 1458 (C=C), 1227, 1153 (S=), 145, 924 (Si a ), 974 (W= d ), 882 (W b W), 795 (W c W)
S15 1 163 154 1458 1226 1153 164 958 885 786 1 1 1 1 1 Figure S3-9. FT-IR of [4 2H] 3 [PMo 12 ] 2 on KBr Pellet. FT-IR (KBr, cm -1 ): ν = 163 (C=N, C N), 154, 1458 (C=C), 1226, 1153 (S=), 164 (P a ), 958 (Mo= d ), 885 (W b W), 786 (W c W). 1 1581 1467 1228 1155 141 896 1 981 811 1 1 1 1 1 Figure S3-1. FT-IR of [5 H] 3 [PW 12 ] on KBr Pellet. FT-IR (KBr, cm -1 ): ν = 1581 (C=N), 1467 (C H in CH 3 ), 1228, 1155 (S=), 1, 141 (P a ), 981 (W= d ), 896 (W b W), 811 (W c W).
S16 1 1581 1467 1153 1127 145 882 974 924 795 1 1 1 1 1 Figure S3-11. FT-IR of [5 H] 4 [SiW 12 ] on KBr Pellet. FT-IR (KBr, cm -1 ): ν = 1581 (C=N), 1467 (C H in CH 3 ), 1227, 1153 (S=), 145, 924 (Si a ), 974 (W= d ), 882 (W b W), 795 (W c W). 1 1581 1467 1226 1153 164 958 885 786 1 1 1 1 1 Figure S3-12. FT-IR of [5 H] 3 [PMo 12 ] on KBr Pellet. FT-IR (KBr, cm -1 ): ν = 1581 (C=N), 1467 (C H in CH 3 ), 1226, 1153 (S=), 164 (P a ), 958 (Mo= d ), 885 (W b W), 786 (W c W).
S17 1 1637 1485 1439 1228 1155 141 896 1 981 742 811 687 723 1 1 1 1 1 Figure S3-13. FT-IR of [7 H] 3 [PW 12 ] on KBr Pellet. FT-IR (KBr, cm -1 ): ν = 1637, 1485 (C=C), 723, 687 (C H), 1439 (P Ar), 742 (P CH 2 ), 1228, 1155 (S=), 1, 141 (P a ), 981 (W= d ), 896 (W b W), 811 cm 1 (W c W). 1 1637 1485 1439 1227 1153 145 882 687 742 974 723 924 795 1 1 1 1 1 Figure S3-14. FT-IR of [7 H] 4 [SiW 12 ] on KBr Pellet. FT-IR (KBr, cm -1 ): ν = 1637, 1485 (C=C), 723, 687 (C H), 1439 (P Ar), 742 (P CH 2 ), 1227, 1153 (S=), 145, 924 (Si a ), 974 (W= d ), 882 (W b W), 795 cm 1 (W c W).
S18 1 1485 1637 1439 1226 1153 164 958 885 687 742 723 796 1 1 1 1 1 Figure S3-15. FT-IR of [7 H] 3 [PMo 12 ] on KBr Pellet. FT-IR (KBr, cm -1 ): ν = 1637, 1485 (C=C), 723, 687 (C H), 1439 (P Ar), 742 (P CH 2 ), 1226, 1153 (S=), 164 (P a ), 958 (Mo= d ), 885 (W b W), 796 (W c W). Figure S4. GC-MS analysis 3.x1 5 81.1 Intensity 2.5x1 5 2.x1 5 1.5x1 5 1.x1 5 126.1 5.x1 4 53.1 97. 39.1 31.1 69.1. 1 1 1 m/z H Figure S4-1. MS of 5-hydroxymethylfurfural m/z =126.1
S19 Intensity 2.5x1 5 2.x1 5 1.5x1 5 1.x1 5 5.x1 4 81. 53. 69.1 43.1 19. 125. 97. 154. 3.1. 1 1 m/z 1 1 1 Figure S4-2. MS of 5-ethoxymethylfurfural m/z = 154.1 4.x1 6 3.5x1 6 183.1 Intensity 3.x1 6 2.5x1 6 2.x1 6 1.5x1 6 19. m/z = 228.1 1.x1 6 155.1 5.x1 5 81. 125. 3.1 53.1 97. 228.1 138.1 169.1. 41.1 69. 1 1 1 1 1 2 2 m/z Figure S4-3. MS of 2-(diethoxymethyl)-5-(ethoxymethyl)furan
S 1.4x1 5 1.2x1 5 99. Intensity 1.x1 5 8.x1 4 6.x1 4 43. 19. m/z = 144.1 4.x1 4 74. 2.x1 4 55. 144. 32. 87.1 116.. 1 1 1 1 1 m/z Figure S4-4. MS of ethyl levulinate 1.x1 7 8.x1 6 19.1 97.1 Intensity 6.x1 6 4.x1 6 81.1 m/z = 182.1 153.1 53.1 2.x1 6 41.1 182.1 69.1 125.1 3.1. 1 1 m/z 1 1 1 Figure S4-5. MS of 5- butoxymethylfurfural
S21 6x1 5 211.1 Intensity 5x1 5 4x1 5 3x1 5 19. 2x1 5 81. 183.1 1x1 5 53.1 125. 41.1 97. 138.1 169.1 69. 31. 153. 256.1 1 1 1 1 1 2 2 2 2 m/z Figure S4-6. MS of 2-(1 -butoxymethyl-1 -hydroxyl)-5-(butoxymethyl)furan m/z =256.2 H 8.x1 6 99.1 Intensity 6.x1 6 4.x1 6 43.1 74.1 2.x1 6 56.1 117.1 13.1 157.1 31.1 81.1 143.1 173.1. 1 1 1 1 1 m/z Figure S4-7. MS of butyl levulinate m/z = 172.1