# US 11,440,894 B2 · Process development for 5-hydroxymethylfurfural (5-HMF) synthesis from carbohydrates

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- Number: US 11,440,894 B2
- Document ID: US11440894B2
- Status: Granted
- Kind: B2
- Application number: 17/254,959
- Filed: 2019-02-14
- Published: 2021-04-29
- Granted: 2022-09-13
- Earliest claimed: 2018-06-22
- Assignees: Council of Scientific and Industrial Research
- Applicants: Council of Scientific and Industrial Research
- Inventors: Pralay Das; Ajay Kumar; Shaifali
- Web page: https://patentgrep.com/patent/US11440894B2

## CPC

- C07D 307/48: Furfural
- C07D 307/50: Preparation from natural products
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)

## 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

### Claim 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 Na2SO4; and
evaporating solvent from the reaction mixture under reduced pressure to yield the 5-hydroxymethylfurfural.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 1)

The single-pot process of claim 1, wherein the inorganic acid is selected from AlCl3 and HCl.

### Claim 4 (depends on 1)

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 AlCl3; and
from 25% to 35% by weight HCl (4N),
wherein the oxalic acid dihydrate, the AlCl3, and the HCl (4N) are added to the reaction mixture in equal proportion by volume.

### Claim 5 (depends on 1)

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.

### Claim 6 (depends on 1)

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.

### Claim 7 (depends on 1)

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.