Oxidation of 5-hydroxymethylfurfural to maleic anhydride with molecular oxygen

Transcription

1 Supporting Information for xidation of 5-hydroxymethylfurfural to maleic anhydride with molecular oxygen Zhongtian Du, a Jiping Ma, a,b Feng Wang, a Junxia Liu, a,b and Jie Xu a, * a State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 11623, China b Graduate University of the Chinese Academy of Sciences, Beijing 139, China Fax: (+86) xujie@dicp.ac.cn Contents: 1. General Equipments and Materials (pp. 2-4) 2. Typical Procedure and Products Analysis (pp. 5-7) 3. Additional Results (pp.8 and 9) 4. riginal GC,GC-MS, NMR and Photo Traces (pp.1-14) 1

2 1. General Equipments and Materials The typical experiments were carried out in a closed glass-lined stainless steel autoclave equipped with a magnetic stirring, a pressure gauge and automatic temperature control apparatus. 1 H NMR and 13 C NMR spectra were recorded on a Bruker 4 MHz spectrometer at room temperature in DMS-d 6. GC-MS was performed on Agilent 689N GC/5973MS. 5-Hydroxymethylfurfural (HMF) was purchased from Wutong Aroma Chemicals Co., Ltd. 5-(Hydroxymethyl)furfuryl alcohol was obtained from Toronto Research Chemical Inc and used without further purification. 2,5-Diformylfuran (DFF) was synthesized by oxidation of HMF using our previous method (Fig. S2 and S3). 1 2,5-Furandicarboxylic acid was prepared by oxidation of DFF with KMn 4 (Fig. S4, S5 and S12). 2 Furfuryl alcohol was distilled under reduced pressure before use. 5-Methylfurfuryl alcohol was obtained from Acros rganics and used without any pretreatment. Acetonitrile contained about 1% (v/v) acetic acid. All other reagents were commercial available and used as received. V(acac) 2 was purchased from Alfa Aesar and used without further purification. VS 4 xh 2 (USP28) was dried at 12 o C overnight. V(pic) 2 [bis(pyridine-2-carboxylato)oxovanadium(iv)] and V(mal) 2 [bis(maltolato)oxovanadium (IV)] was synthesized according to the literatures. 3,4 References: Fig. S1: Molecular structures and abbreviation of some HMF derivatives 1 J. P. Ma, Z. T. Du, J. Xu, Q. H. Chu and Y. Pang, Chemsuschem, 21, DI: 1.12/cssc D. W. Yoon, D. E. Gross, V. M. Lynch, J. L. Sessler, B. P. Hay and C. H. Lee, Angew. Chem. Int. Ed., 28, 47, (See its ESI-5) 3 M. Melchior, K. H. Thompson, J. M. Jong, S. J. Rettig, E. Shuter, V. G. Yuen, Y. Zhou, J. H. McNeill and C. rvig, Inorg. Chem., 1999, 38, P. Caravan, L. Gelmini, N. Glover, F. G. Herring, H. L. Li, J. H. McNeill, S. J. Rettig, I. A. Setyawati, E. Shuter, Y. Sun, A. S. Tracey, V. G. Yuen and C. rvig, J. Am. Chem. Soc., 1995, 117,

3 b a a b Fig. S2: 1 H NMR (DMS-d 6 ) of 2,5-diformylfuran (The signal at 2.5 is attributed to DMS solvent residue, and that of at 3.3 is attributed to water existed in DMS-d 6 ) Fig. S3: 13 C NMR (DMS-d 6 ) of 2,5-diformylfuran (DFF) 3

4 b H b H a a Fig. S4: 1 H NMR (DMS-d 6 ) of 2,5-furandicarboxylic acid (The signal at 2.5 is attributed to DMS solvent residue) H H Fig. S5: 13 C NMR (DMS-d 6 ) of 2,5-furandicarboxylic acid 4

5 2. Typical Procedure and Products Analysis 2.1 Typical Procedure for Catalytic xidation A typical procedure for catalytic oxidation of HMF was as follows: V(acac) 2 (33.1 mg,.125 mmol) and HMF (315 mg, 2.5 mmol) was placed into the autoclave followed by 5 ml acetonitrile. After the autoclave was closed, oxygen was charged to 1. MPa. It was heated to 9 o C within 2 min. The oxygen was recharged if consumed during the oxidation. After 4 h (heating period is not included), the autoclave was cooled to room temperature and carefully depressurized to normal pressure. Then the products were analyzed by GC. 2.2 GC Measurements The attempt to analyze all these products using HPLC directly failed, as it was difficult to separate all compounds perfectly. GC was used to determine products. Gas chromatography measurements were conducted on Agilent 789A GC with autosampler and a flame ionization detector. DB-17 capillary column was used for separation of products. 1,2,4,5-tetramethylbenzene (TMB) was used as an internal standard. The amounts of maleic anhydride (MA), DFF and residual HMF were determined by GC with internal standard method. They were identified by GC-MS and by comparison with authentic compounds. The HMF conversion (mol%) and the yield (mol%) of main furan products were calculated using the amount of initial HMF as the denominator and the absolute amount of DFF or MA as the numerator, as shown below: 5

6 Notes: Scheme S1: Steps for the determination of DFF and the residual HMF Scheme S2: Steps for the determination of MA MA is reactive with water. Maleic acid indeed existed in the products (Fig. S13). However, there is no signal for maleic acid on GC. In order to study the oxidation conveniently and accurately, we transform the maleic acid to maleic anhydride by dehydration with excess acetic anhydride before GC determination. This pretreatment was verified using pure maleic acid experimentally. The procedure is as follows: After cooled and depressurized, all the crude mixture was transferred to 5 ml round-bottomed flask with condenser tubes followed by 5 ml acetic anhydride. The mixture was heated to reflux for 2 h under stirring (Scheme S2). Therefore two parallel experiments were performed to get data. The yield of DFF was obtained directly by GC measurement without dehydration with acetic anhydride; and the residual HMF was also determined without dehydration. The total yield of MA including maleic acid was obtained by GC measurement after dehydration with acetic anhydride (Fig. S1); The yield of maleic acid was calculated as the MA yield difference between two parallel experiments with and without treatment of acetic anhydride (Fig. S1). 6

7 2.3 Products Distribution Reaction conditions: 2.5 mmol HMF,.125 mmol V(acac) 2, 5 ml CH 3 CN, 9 o C, 4 h, 1. MPa 2. Conversion of HMF: 99% The yields were calculated as the molar ratio of their amounts to the initial HMF loaded. Total yield of MA including maleic acid: 52% (35% MA and 17% maleic acid); Yield of DFF: 14%; 1% byproducts were mainly derived from the esterification of formic acid and HMF. Quantification was estimated using the FID response factors of DFF. Formic acid and carbon dioxide was also detected, which was confirmed by MS and NMR (Fig. S13). Caution! The formic acid is harmful to eyes. Little 2,5-furandicarboxylic acid existed and this was confirmed by GC-MS (after esterification with excess methanol) and NMR investigation (Fig. S11-S13). Scheme S3: Proposed main reactions and side reactions 7

8 3. Additional Results 3.1 Experimental Results MA Internal standard DFF MA 4. h 2. h HMF 1. h.5 h 5-HMF GC Retention time / min Fig. S6: GC traces at different reaction time Reaction conditions: 2.5 mmol HMF,.125 mmol V(acac) 2, 5 ml CH 3 CN, 9 o C, 1. MPa 2. MA 4. h 2. h 1. h.5 h 5-HMF Chemical Shift / ppm Fig. S7: 1 H NMR (DMS-d 6 ) of crude products without any purification after removing CH 3 CN Reaction conditions: 2.5 mmol HMF,.125 mmol V(acac) 2, 5 ml CH 3 CN, 9 o C, 1. MPa 2 8

9 1 Conversion of HMF Yield of DFF Yield of MA mol% t (h) Fig. S8: Time course for oxidation of HMF. Reaction conditions: 2.5 mmol HMF,.125 mmol V(acac) 2, 5 ml CH 3 CN, 9 o C, 1. MPa Calculated Results Density functional theory (DFT) method with the B3-LYP functional and the TZVP basis. Fig. S9: Calculated results of HMF related molecules 9

10 4. riginal GC,GC-MS, NMR and Photo Traces 4.1 Products from oxidation of HMF Reaction conditions: 2.5 mmol HMF,.125 mmol V(acac) 2, 5 ml CH 3 CN, 9 o C, 4 h, 1. MPa 2. Little 2,5-furandicarboxylic acid occurred during oxidation of HMF. (1) GC traces pa 8 FID1 A, 前部信号 (DU\DU \14F31.D) TMB Without treatment of acetic anhydride MA DFF min pa 8 FID1 A, 前部信号 (DU\DU \11F11.D) MA 2.69 TMB After treatment of acetic anhydride min Fig. S1: GC traces for parallel experiments without/with treatment of acetic anhydride. 1,2,4,5-tetramethylbenzene (TMB) was used as an internal standard. 1

11 (2) The GC-MS traces of reaction mixture after esterification with methanol Abundance 1 TIC: D 1419C.D \data.m s Tim e --> t=4.31 min (Text File) Scan 588 (4.31 min): D1419C.D\ data.ms (-493) Standard (replib) 2-Butenedioic acid (Z)-, dimethyl ester Fig. S11: The GC-MS traces of reaction mixture after esterification. After oxidation, the reaction mixture was heated under reflux in 1 ml methanol catalyzed by concentrated sulfuric acid for 6 h. 11

12 Abundance 35 3 TIC: D 1429A.D \data.m s Tim e --> t=7.11 min (Text File) Scan 1296 (7.11 min): D1429A.D\ data.ms Standard (mainlib) 2,5-Furandicarboxylic acid, dimethyl ester Fig. S12: The GC-MS of pure 2,5-furandicarboxylic acid after esterification in excess methanol (the GC-MS conditions are the same as Fig. S11) 12

13 (3) NMR traces after removing CH 3 CN H H S H H Fig. S13: 1 H NMR (DMS-d 6 ) of crude products without any purification after removing CH 3 CN (The signal at 2.5 is attributed to DMS solvent residue) 4.2 Products from oxidation of DFF Reaction conditions: 2.5 mmol DFF,.125 mmol V(acac) 2, 5 ml CH 3 CN, 9 o C, 4 1. MPa 2, 4 h. No 2,5-furandicarboxylic acid was detected during oxidation of DFF either. (1) GC traces pa 16 FID1 A, 前部信号 (DU\DU \17F11.D) DFF TMB min Fig. S14: The GC trace for mixture of DFF oxidation. TMB was used as an internal standard. 13

14 (2) NMR traces after removing CH 3 CN Fig. S15: 1 H NMR (DMS-d 6 ) of crude products without any purification after removing CH 3 CN (The signal at 2.5 is attributed to DMS residue, and that of at 3.3 is attributed to water existed in DMS-d 6 ) 4.3 Photo of Products from oxidation of HMF in CH 2 Cl 2 Fig. S16: Black insoluble formed during the oxidation of HMF in CH 2 Cl 2 14