Method for producing levulinic acid

Patent metadata

Field	Value
Publication number	US-12492159-B2
Application number	US-202318135054-A
Country	US
Kind code	B2
Filing date	Apr 14, 2023
Priority date	Apr 22, 2022
Publication date	Dec 9, 2025
Grant date	Dec 9, 2025

Abstract

The present disclosure relates to a process for producing levulinic acid from the technical lignin. The technical lignin is rich in lignin and ash and do not have any other use and usually incinerated as a waste management strategy. During the incineration process, the cellulose also gets burnt and wasted. In the present disclosure, there is provided an economical and environmentally friendly process to produce levulinic acid from the technical lignin by using a synergistic combination of catalysts for high yields and high titer with acid recycling in a cost-effective manner.

First claim

We claim:

1 . A process for producing levulinic acid from technical lignin, the process comprising:
a) treating technical lignin with a combination of formic acid and technical spirit in a high-pressure reactor (HPR) for obtaining cellulose and lignin; b) subjecting the cellulose of step a) to a treatment with a catalyst to obtain a slurry; c) centrifuging the slurry to obtain a levulinic acid containing liquid fraction; d) mixing the levulinic acid containing liquid fraction with a solvent to obtain an organic mixture and an acidic aqueous liquid waste; e) evaporating the solvent from the organic mixture to obtain levulinic acid; and f) recycling the acidic aqueous liquid waste of step d) and solvent of step d) for a subsequent cycle of levulinic acid extraction and purification; wherein the technical lignin comprises 10-25% cellulose, 0-5% hemicellulose, 25-55% lignin and 20-50% ash content.

2 . The process as claimed in claim 1 , wherein the formic acid and technical spirit are present in the combination in a ratio of 1:1.

3 . The process as claimed in claim 1 , wherein the high-pressure reactor (HPR) is operated at a temperature in a range of 160-180° C., and wherein the technical lignin is treated with the combination of formic acid and technical spirit for 1 hour.

4 . The process as claimed in claim 1 , wherein the catalyst comprises a combination of mineral acid and lewis acid.

5 . The process as claimed in claim 1 , wherein the cellulose is subjected to the catalyst treatment at a temperature in a range of 80-200° C. for 30-60 minutes.

6 . The process as claimed in claim 1 , wherein the solvent is selected from the group consisting of dichloromethane, diethyl ether and ethyl acetate.

7 . The process as claimed in claim 1 , wherein the levulinic acid containing liquid fraction and the solvent are present in 1:3 ratio.

8 . The process as claimed in claim 1 , wherein an yield of the levulinic acid is 71% of the theoretical yield.

9 . The process as claimed in claim 1 , wherein the technical spirit comprises 85% of ethanol, 5% of acetic acid, 5% of acetaldehyde and 5% of water.

10 . The process as claimed in claim 4 , wherein the mineral acid is selected from the group consisting of sulphuric acid, hydrochloric acid, nitric acid and phosphoric acid; and wherein the lewis acid is selected from the group consisting of aluminium chloride, ferric chloride and chromium chloride.

11 . The process as claimed in claim 1 , wherein 10-30% w/v of cellulose loading is used in step b) of the process.

12 . The process as claimed in claim 1 , wherein the catalyst is a combination of sulphuric acid and ferric chloride.

13 . The process as claimed in claim 1 , wherein the catalyst is added at a concentration of 4% (v/v) in the HPR at a temperature of 200° C.

14 . The process as claimed in claim 1 , wherein the process yields levulinic acid in a range of 34.7-65.1 wt % with 88% purity.

Assignees

• Indian Oil Corp Ltd
• Dept Of Biotechnology India

Inventors

• Satlewal Alok
• Agrawal Ruchi
• Kumar Ravindra
• Gupta Ravi Prakash
• RAMAKUMAR Sankara Sri Venkata

Classifications

• C07C59/185

  Saturated compounds having only one carboxyl group and containing keto groups · CPC title

• C07C51/487 Primary

  by treatment giving rise to chemical modification (by chemisorption C07C51/47) · CPC title

• C07C51/00 Primary

  Preparation of carboxylic acids or their salts, halides or anhydrides (of acids by hydrolysis of oils, fats or waxes C11C) · CPC title