# US 10,865,190 B2 · Processes for preparing 2,5-furandicarboxylic acid and esters thereof

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- Number: US 10,865,190 B2
- Document ID: US10865190B2
- Status: Granted
- Kind: B2
- Application number: 16/447,153
- Filed: 2019-06-20
- Published: 2019-10-03
- Granted: 2020-12-15
- Earliest claimed: 2015-07-24
- Assignees: E. I. Du Pont de Nemours and Company
- Applicants: E I Du Pont De Nemours and Company
- Inventors: Pranit S Metkar; Ronnie Ozer; Bhuma Rajagopalan
- Web page: https://patentgrep.com/patent/US10865190B2

## CPC

- C07D 307/68: Carbon atoms having three bonds to hetero atoms with at the most one bond to halogen
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)

## Abstract

A process for producing furan dicarboxylic acid or an ester thereof from a feedstock comprising hydroxymethyl furfural (HMF) and humins is disclosed. Humins are a byproduct from reactions forming HMF from sugars and are typically removed from the HMF prior to any further processing. A humins-containing HMF feedstock is utilized to produce furan dicarboxylic acids and ester substantially free from humins.

## Claims

### Claim 1

A process comprising:
a) oxidizing a feedstock comprising hydroxymethyl furfural and humins to produce a mixture comprising crude humins-containing 2,5-furan dicarboxylic acid;
b) separating the mixture to obtain a solid 2,5-furan dicarboxylic acid/humins composition;
c) esterifying the solid 2,5-furan dicarboxylic acid/humins composition with an alcohol to produce a crude ester of 2,5-furan dicarboxylic acid; and
d) purifying the crude ester of 2,5-furan dicarboxylic acid obtained in step c) by distillation or by sublimation to produce a purified ester of 2,5-furan dicarboxylic acid comprises less than 100 ppm humins as determined by size exclusion chromatography.

### Claim 2 (depends on 1)

The process of claim 1 wherein the purified ester of 2,5-furan dicarboxylic acid is 2,5-furan dicarboxylic acid dimethyl ester.

### Claim 3

A process comprising:
i) oxidizing a feedstock comprising hydroxymethyl furfural and humins in a solvent to produce a mixture comprising crude humins-containing 2,5-furan dicarboxylic acid;
ii) filtering the mixture under high temperature to obtain a filtrate comprising 2,5-furan dicarboxylic acid comprises less than 100 ppm humins as determined by size exclusion chromatography, wherein the filtration temperature is sufficiently high to keep the 2,5-furan dicarboxylic acid soluble in the solvent;
iii) esterifying the 2,5-furan dicarboxylic acid substantially free of humins with an alcohol to produce a crude ester of 2,5-furan dicarboxylic acid; and
iv) purifying the crude ester of 2,5-furan dicarboxylic acid obtained in step iii) by distillation or sublimation to obtain a purified ester.

### Claim 4 (depends on 3)

The process of claim 3 wherein the ester of 2,5-furan dicarboxylic acid is 2,5-furan dicarboxylic acid dimethyl ester.

### Claim 5 (depends on 3)

The process of claim 3 wherein the high temperature of the filtration step ii) is in the range of from 50° C. to 200° C.

### Claim 6 (depends on 3)

The process of claim 3 wherein the solvent is acetic acid or acetic acid and water.

### Claim 7 (depends on 3)

The process of claim 3 wherein the purified ester of 2,5-furan dicarboxylic acid comprises less than 100 ppm humins as determined by size exclusion chromatography, a b* value of less than 3 as determined by LAB color measurement, and greater than 99 percent by weight of the diester of 2,5-furan dicarboxylic acid, based on the total weight of the purified ester of 2,5-furan dicarboxylic acid.

### Claim 8 (depends on 3)

The process of claim 3, wherein at least a portion of the alcohol is replaced with an alcohol source.

### Claim 9 (depends on 1)

The process of claim 1 wherein the purified ester of 2,5-furan dicarboxylic acid comprises a b* value of less than 3 as determined by LAB color measurement, and greater than 99 percent by weight of the diester of 2,5-furan dicarboxylic acid, based on the total weight of the purified ester of 2,5-furan dicarboxylic acid.

### Claim 10 (depends on 1)

The process of claim 1, wherein at least a portion of the alcohol is replaced with an alcohol source.