# US 9,775,347 B2 · Methods to convert lignin to phenolic and carboxylate compounds

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- Number: US 9,775,347 B2
- Document ID: US9775347B2
- Status: Granted
- Kind: B2
- Application number: 14/898,442
- Filed: 2013-06-14
- Published: 2016-05-19
- Granted: 2017-10-03
- Earliest claimed: 2013-06-14
- Assignees: Washington State University
- Applicants: Washington State University Research Foundation
- Inventors: Xiao Zhang
- Web page: https://patentgrep.com/patent/US9775347B2

## CPC

- A01N 37/02: Saturated carboxylic acids or thio analogues thereof; Derivatives thereof
- A01N 31/08: Oxygen or sulfur directly attached to an aromatic ring system
- A01N 31/14: Ethers
- A01N 35/04: containing aldehyde or keto groups, or thio analogues thereof, directly attached to an aromatic ring system, e.g. acetophenone; Derivatives thereof, e.g. acetals
- A01N 37/40: having at least one carboxylic group or a thio analogue, or a derivative thereof, and one oxygen or sulfur atom attached to the same aromatic ring system
- A01N 61/00: Biocides, pest repellants or attractants, or plant growth regulators containing substances of unknown or undetermined composition, e.g. substances characterised only by the mode of action
- C07C 27/00: Processes involving the simultaneous production of more than one class of oxygen-containing compounds
- C07C 45/59: in five-membered rings (from ozonides C07C45/40)
- C07C 51/31: of cyclic compounds with ring-splitting
- C10G 3/00: Production of liquid hydrocarbon mixtures from oxygen-containing organic materials, e.g. fatty oils, fatty acids (production from non-melting solid oxygen-containing carbonaceous materials C10G1/00)
- C10G 3/50: {in the presence of hydrogen, hydrogen donors or hydrogen generating compounds}
- Y02P 30/20: using bio-feedstock
- A01N: PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF (preservation of food or foodstuff A23); BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES (preparations for medical, dental or toiletry purposes which kill or prevent the growth or proliferation of unwanted organisms A61K); PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C10G: CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION (cracking to hydrogen or synthesis gas C01B; cracking or pyrolysis of hydrocarbon gases to individual hydrocarbons or mixtures thereof of definite or specified constitution C07C; cracking to cokes C10B); RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A method of converting lignin to phenolic compounds and dicarboxylates in high yield is described. The method involves the use of peroxy acids to react with lignin at a moderated treatment conditions. The peroxy acids can be used along or in combination of other catalysts that have the capability to lower the molecular weight of lignin. A phenolic compounds yield is achieved (>60%) and these phenolic compounds represents high value precursors for various applications include but not limited to antioxidants, health improvement agents, anticorrosive agents, liquid fuel components and performance enhancing agents, resin and adhesives. Dicarboxylic acids can be used for polymer applications or hydrodeoxygenation to hydrocarbon fuel.

## Claims

### Claim 1

A process comprising:
oxidatively depolymerizing a lignin with a peroxy acid at a temperature of not less than about 5° C. to not greater than about 160° C. to yield a mixture of dicarboxylic acid compounds and a mixture of phenolic compounds, wherein the mixture of dicarboxylic acid compounds is in at least about 10% total weight yield, wherein the total weight yield is calculated from the lignin on a contained lignin basis.

### Claim 2 (depends on 1)

The process of claim 1, wherein the mixture of phenolic compounds is in at least about 28% the total weight yield.

### Claim 3 (depends on 1)

The process of claim 1, further comprising:
substantially separating one or more dicarboxylic acid compounds or combination thereof from the mixture of phenolic compounds;
reducing at least one of the dicarboxylic acid compounds to a saturated dicarboxylic acid; and
recovering the one or more dicarboxylic acids or combination thereof in at least about 10% the total weight yield.

### Claim 4 (depends on 1)

The process of claim 1, further comprising:
substantially separating one or more dicarboxylic acid compounds or combination thereof from the mixture of phenolic compounds;
esterifying at least one of the dicarboxylic acid compounds to a dicarboxylate ester; and
recovering one or more dicarboxylate esters or combination thereof in at least about 10% the total weight yield.

### Claim 5 (depends on 1)

The process of claim 1, wherein the mixture of phenolic compounds is in at least about 60% the total weight yield.

### Claim 6 (depends on 1)

The process of claim 1, wherein the mixture of dicarboxylic acid compounds is at least about 25% the total weight yield.

### Claim 7 (depends on 1)

The process of claim 1, wherein the lignin is an alkaline lignin.

### Claim 8 (depends on 1)

The process of claim 1, wherein the oxidatively depolymerizing the lignin with the peroxy acid comprises oxidatively depolymerizing at the temperature of not less than about 40° C. to not greater than about 120° C.

### Claim 9 (depends on 1)

The process of claim 1, wherein the oxidatively depolymerizing the lignin with the peroxy acid comprises oxidatively depolymerizing for at least 3 hours.

### Claim 10 (depends on 1)

The process of claim 1, wherein the peroxy acid comprises peracetic acid, performic acid, or combinations thereof.

### Claim 11 (depends on 1)

The process of claim 1, wherein the peroxy acid is a peroxyaryloic acid.

### Claim 12 (depends on 1)

The process of claim 1, wherein the peroxy acid is a peroxybenzoic acid.

### Claim 13 (depends on 1)

The process of claim 1, wherein the peroxy acid is selected from the group consisting of metachloro-peroxybenzoic acid, peroxymonosulfuric acid, and peroxysulfonic acid.

### Claim 14 (depends on 1)

The process of claim 1, wherein the peroxy acid is generated in-situ from an organic acid and hydrogen peroxide.

### Claim 15 (depends on 1)

The process of claim 1, wherein the mixture of phenolic compounds comprises vanillin, vanillic acid, and gallic acid.

### Claim 16 (depends on 4)

The process of claim 4, wherein recovering the one or more dicarboxylate esters comprises recovering a dicarboxylate ester fraction comprising a dialkyl muconate, a dialkyl succinate, a dialkyl maleate, or a combination thereof.