Process development for 5-hydroxymethylfurfural (5-HMF) synthesis from carbohydrates

Abstract

The present invention relates to a new protocol for “Process development for 5-hydroxymethylfurfural (5-HMF) synthesis from carbohydrates”. A convenient, atom-economic, highly selective and cost-effective process has been developed for the preparation of 5-HMF from cellulose, hemicellulose, starch, different sources of carbohydrates and further extended to glucose and fructose.

Claims

1. A single-pot process for the preparation of 5-hydroxymethylfurfural, the single-pot process comprising: reacting carbohydrates with oxalic acid and inorganic acids in the presence of a biphasic solvent and a carbon material at a temperature from 110° C. to 160° C. for a time period of from 6 hours to 12 hours under vigorous stirring to form a reaction mixture; and drying the reaction mixture over Na.sub.2SO.sub.4; and evaporating solvent from the reaction mixture under reduced pressure to yield the 5-hydroxymethylfurfural.

2. The single-pot process of claim 1, wherein the carbohydrates are selected from the group consisting of cellulose, polysaccharide, starch, hemicellulose, cellulose derived from rice straw, potato waste starch, glucose, and fructose.

3. The single-pot process of claim 1, wherein the inorganic acid is selected from AlCl.sub.3 and HCl.

4. The single-pot process of claim 1, wherein the reaction mixture comprises: oxalic acid dihydrate at a molar concentration of 1 equivalent; from 10% to 15% by weight AlCl.sub.3; and from 25% to 35% by weight HCl (4N), wherein the oxalic acid dihydrate, the AlCl.sub.3, and the HCl (4N) are added to the reaction mixture in equal proportion by volume.

5. The single-pot process of claim 1, wherein the carbon material is selected from the group consisting of activated carbon, carbon building block, material constituted with carbon, polycarbon material, graphene, carbon nanotubes, and carbon nanorods.

6. The single-pot process of claim 1, wherein the biphasic solvent is selected from the group consisting of methyl isobutyl ketone, 2-butanol, and dimethylsulfoxide.

7. The single-pot process of claim 1, wherein evaporating solvent from the reaction mixture further comprises: performing an extraction with an extraction solvent selected from the group consisting of alkyl ketones, ethyl acetate, dichloromethane, chloroform, tetrahydrofuran, and ether; and evaporating the extraction solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) In an embodiment of the present invention there is provided a “Process development for 5-hydroxymethylfurfural (5-HMF) synthesis from carbohydrates” which comprises in situ steps following hydrolysis of polysaccharides to monomeric unit (glucose), isomerization of monomer i.e. glucose to fructose and dehydrative approach for 5-HMF formula 1 synthesis.

(2) In another embodiment of the present invention there is provided aproblematic, tedious and low yielding approach of cellulose to 5-HMF synthesis in large scale process development has been solved under this method.

(3) In yet another embodiment of the present invention there is provided aa method for the synthesis of 5-HMF starting from cellulose in a one-pot reaction, avoiding high cost reagents.

(4) In still another embodiment of the present invention, the same process is applicable for conversion of hemicellulose, starch, raw potato waste, other polysaccharides and monomer units (such as glucose and fructose) to high yielding 5-HMF synthesis.

(5) In yet another embodiment of the present invention, the modified synthetic approach was found to be highly selective, high yielding and applicable for large scale production of 5-HMF from different carbohydrates.

(6) In still another embodiment of the present invention, the combined reaction media also help to restrict molecules for unusual over-reaction, improve yields and make the whole process easy to purify product, 5-HMF from reaction mixture with −80-98% purity without tedious purification process.

(7) In yet another embodiment of the present invention, the whole modified system also restricts unwanted polymerization and dark colour formation under reaction condition.

(8) In still another embodiment of the present invention, the scale-up process for 5-HMF synthesis as platform compound further could be applicable for several industrially important precursors such as FDCA: 2,5-furanedicarboxylic acid, DMF: 2,5-dimethylfuran, DHMF: 2,5-dihydroxymethylfuran, DFF: 2,5-diformylfural, LA: levulinic acid and other fine chemicals synthesis for industrial or biochemical use (Scheme 1).

(9) ##STR00001##

EXAMPLES

(10) Following examples are given by way of illustration and therefore should not be construed to limit the scope of the invention. In the present invention, Rice straw derived cellulose obtained from Oryza Sativa plant Family: Gramineae and Purchased from farmer field, Village & post office: Trehal, Tehsil-Baijnath, Dist-Kangra, Pin-176061, H.P, whereas waste Raw Potato [Solanum Tuberosum; Family: Solanaceae] purchased from Raj Kumar, Krishan Lals Co. Fruits & Vegetables, Commission agents, Shop No. 2, New Sabzi Mandi, Palampur-176061, H.P. Cellulose, starch and fructose purchased from CDH Pvt. Ltd. Corp. Office, 7/28 Vardaan House, Daryaganj, New Delhi-110002 and Glucose purchased from Sigma Aldrich Chemicals Pvt. Ltd, Plot-12, Banglore-560100

(11) General Experimental Description:

(12) ##STR00002##

(13) An oven dried round bottomed flask was charged with equivalent amount of carbohydrate (1 equiv.) and oxalic acid dihydrate (1 equiv.). Then 10-15 wt % AlCl.sub.3, 20-30 wt % activated charcoal, 25-35 wt % HCl (4N), MIBK:2-butanol (3:1) and DMSO were added in equal proportion by volume to the reaction mixture and heated at 100-160° C. for 6-12 h under vigorous stirring condition. The compound 1 (5-HMF) was extracted from reaction mixture by ethyl acetate/CHCl.sub.3/CH.sub.2Cl.sub.2, dried over Na.sub.2SO.sub.4 and evaporated under reduced pressure.

Example 1

(14) Cellulose to 5-HMF Synthesis:

(15) An oven dried round bottomed flask (500 mL) was charged with cellulose powder (20 g), oxalic acid dihydrate (20 g), AlCl.sub.3 (3 g), activated charcoal (4 g), HCl (4N, 18 mL), MIBK: 2-butanol (90:30) mL and DMSO (120 mL) and heated at 110° C. for 6 h under vigorous stirring condition. The compound 1 (5-HMF) was extracted from reaction mixture by ethyl acetate, dried (Na.sub.2SO.sub.4) and evaporated under reduced pressure gave compound 1, 13.00 g (65 wt %, 93 mol %.sup.a). .sup.1H NMR (300 MHz, CDCl.sub.3) δ 9.37 (s, 1H), 7.12 (d, J=3.5 Hz, 1H), 6.39 (d, J=3.5 Hz, 1H), 4.55 (s, 2H); .sup.13C NMR (300 MHz, CDCl.sub.3) δ 177.65, 161.03, 151.72, 123.49, 109.71, 56.84; m/z MS (ESI) [M+1].sup.+=127, [M+1-H.sub.2O].sup.+=109, [M+1-H.sub.2O—CO].sup.+=81

Example 2

(16) Starch to 5-HMF Synthesis:

(17) An oven dried round bottomed flask (500 mL) was charged with starch (20 g), oxalic acid dihydrate (20 g), AlCl.sub.3 (3 g), activated charcoal (4 g), HCl (4N, 18 mL), MIBK:2-butanol (90:30) mL and DMSO (120 mL) and heated at 110° C. for 6 h under vigorous stirring condition. The compound 1 (5-HMF) was extracted from reaction mixture by ethyl acetate, dried (Na.sub.2SO.sub.4) and evaporated under reduced pressure gave compound 1, 12.80 g (64 wt %, 92 mol %.sup.a) in sufficiently pure form. The spectral data was same as mentioned for compound 1 (Experimental description 1).

(18) .sup.#Mole percent yield was calculated with respect to glucose monomer.

Example 3

(19) Raw Potato Waste to 5-HMF Synthesis:

(20) An oven dried round bottomed flask (250 mL) was charged with dried raw potato (15.45 g), oxalic acid dihydrate (13.50 g), AlCl.sub.3 (2.025 g), activated charcoal (2.700 g), HCl (12N, 1.745 mL), MIBK:2-butanol (45:15) mL and DMSO (60 mL) and heated at 110° C. for 6 h under vigorous stirring condition. The compound 1 (5-HMF) was extracted from reaction mixture by ethyl acetate, dried (Na.sub.2SO.sub.4) and evaporated under reduced pressure gave compound 1, 10.28 g (66 wt %). The spectral data was same as mentioned for compound 1 (Experimental description 1).

Example 4

(21) Rice Straw Derived Cellulose to 5-HMF Synthesis:

(22) An oven dried round bottomed flask (100 mL) was charged with rice straw derived cellulose (1 g), oxalic acid dihydrate (1 g), AlCl.sub.3 (150 mg), activated charcoal (200 mg), HCl (4N, 0.9 mL), MIBK:2-butanol (4.5:1.5) mL and DMSO (6 mL) and heated at 110° C. for 12 h under vigorous stirring condition. The compound 1 (5-HMF) was extracted from reaction mixture by ethyl acetate, dried (Na.sub.2SO.sub.4) and evaporated under reduced pressure gave compound 1, 0.350 g (35 wt %). The spectral data was same as mentioned for compound 1 (Experimental description 1).

Example 5

(23) Glucose to 5-HMF Synthesis:

(24) An oven dried round bottomed flask (100 mL) was charged with glucose (1 g), oxalic acid dihydrate (1 g), AlCl.sub.3 (150 mg), activated charcoal (200 mg), HCl (4N, 0.9 mL), MIBK:2-butanol (4.5:1.5)) mL and DMSO (6 mL) and heated at 110° C. for 6 h under vigorous stirring condition. The compound 1 (5-HMF) was extracted from reaction mixture by ethyl acetate, dried (Na.sub.2SO.sub.4) and evaporated under reduced pressure gave compound 1, 0.650 g (65 wt %, 93 mol %). The spectral data was same as mentioned for compound 1 (Experimental description 1).

Example 6

(25) Fructose to 5-HMF Synthesis:

(26) An oven dried round bottomed flask (100 mL) was charged with fructose (1 g), oxalic acid dihydrate (1 g), AlCl.sub.3 (150 mg), activated charcoal (200 mg), HCl (4N, 0.9 mL), MIBK:2-butanol (4.5:1.5) mL and DMSO (6 mL) and heated at 110° C. for 6 h under vigorous stirring condition. The compound 1 (5-HMF) was extracted from reaction mixture by ethyl acetate, dried (Na.sub.2SO.sub.4) and evaporated under reduced pressure gave compound 1, 0.642 g (64 wt %, 92 mol %). The spectral data was same as mentioned for compound 1 (Experimental description 1).

ADVANTAGE OF THE INVENTION

(27) 1. A simple, atom-economic and cost-effective process has been developed for the preparation of 5-HMF from carbohydrates. 2. Carbohydrates preferably low cost cellulose could be applicable for large-scale production of 5-HMF avoiding harsh reaction condition and tedious purification with high yield. 3. Easy scalable process and purification reduces production cost of 5-HMF assertively. 4. Easy purification and no need of traditional column chromatography, reduces production cost assertively. 5. The process could be applicable for low cost production of highly demanding platform compound 5-HMF and further industrially important high value molecules such as DHMF, DMF, FDCA, DFF and LA. 6. The process could be applicable for low cost production of biopolymer and biofuel from carbohydrates.