Chemically stable lignin derivative and method for preparing same

Patent metadata

Field	Value
Publication number	US-11236119-B2
Application number	US-201816651445-A
Country	US
Kind code	B2
Filing date	Sep 28, 2018
Priority date	Sep 29, 2017
Publication date	Feb 1, 2022
Grant date	Feb 1, 2022

Abstract

A lignin derivative including a unit of general formula (I):in which R1, R2, R3 and R4, which may be identical or different, each represent a hydrogen atom, a methoxy group —OMe, a hydroxyl group, where appropriate protected by a protective group of a hydroxyl function, or aunit R5 represents a hydrogen atom, a protective group of a hydroxyl function or aunit; A represents an oxygen atom, a sulfur atom, an —NH group or an —NR′ group; and R′1, R′2, R′3 and R′4 each represent a hydrogen atom or a substituent not including a mesomeric-effect electron-withdrawing group conjugated to the aromatic ring, a substituent from R′1, R′2, R′3 and R′4 representing the covalent bond with the benzylic carbon.

First claim

What is claimed is:

1. A lignin derivative comprising a unit having the general formula (I):

in which:
R 1 , R 2 , R 3 and R 4 , which may identical or different, each represent a hydrogen atom, an —OMe methoxy group, a hydroxyl group, optionally protected by a hydroxyl-protecting group, or a

motif,
R 5 represents a hydrogen atom, a hydroxyl-protecting group or a

motif,
A represents a sulfur atom or an —NR′ group, where R′ represents a hydrogen atom or a substituent not including any mesomeric-effect electron-withdrawing group conjugated to the aromatic ring,
R′ 1 , R′ 2 , R′ 3 and R′ 4 , which may be identical or different, each represent a hydrogen atom or a substituent not including any mesomeric-effect electron-withdrawing group conjugated to the aromatic ring,
one substituent among R′ 1 , R′ 2 , R′ 3 and R′4 representing the covalent bond with the benzylic carbon,
or one of the salts thereof.

2. The lignin derivative according to claim 1 , wherein R′ 1 and R′2, identical or different, each represent, except for the substituent forming the covalent bond with the benzylic carbon:
a hydrogen atom,
or a linear, branched and/or cyclic, saturated and/or unsaturated, optionally aromatic, carbon radical, which may include a single cycle or a plurality of condensed cycles, optionally substituted, optionally including one or more heteroatoms and/or one or more groups comprising one or more heteroatoms.

3. The lignin derivative according to claim 1 , wherein R′ 3 and R′ 4 , identical or different, each represent, except for the substituent forming the covalent bond with the benzylic carbon:
a hydrogen atom,
a group including an electron-donating radical bonded directly or by conjugation to the aromatic ring,
or a linear, branched and/or cyclic, saturated and/or unsaturated, optionally aromatic, carbon radical, which may include a single cycle or a plurality of condensed cycles, optionally substituted, optionally including one or more heteroatoms and/or one or more groups comprising one or more heteroatoms.

4. The lignin derivative according to claim 1 , wherein at least one substituent among R′ 1 , R′ 2 , R′ 3 and R′ 4 represents a hydrogen atom.

5. The lignin derivative according to claim 1 , wherein R′ 1 represents the covalent bond with the benzylic carbon.

6. The lignin derivative according to claim 1 , wherein R′ 3 and R′ 4 each represent a hydrogen atom.

7. The lignin derivative according to claim 1 , wherein R′ 2 represents a hydrogen atom or an alkyl group.

8. The lignin derivative according to claim 1 , wherein A represents an —NR′ group, wherein R′ represents a hydrogen atom or a C1-C4 alkyl radical, R′ 1 represents the covalent bond with the benzylic carbon, and R′ 2 , R′ 3 and R′ 4 each represent a hydrogen atom.

9. A method for preparing a lignin derivative as claimed in claim 1 , wherein lignin is reacted with a compound having the general formula (II):

in which
A represents a sulfur atom or an —NR′ group, wherein R′ represents a hydrogen atom or a substituent not including any mesomeric-effect electron-withdrawing group conjugated to the aromatic ring,
R′ 1 , R′ 2 , R′ 3 and R′ 4 , which may be identical or different, each represent a hydrogen atom or a substituent not including any mesomeric-effect electron-withdrawing group conjugated to the aromatic ring, at least one substituent among R′ 1 , R′ 2 , R′ 3 and R′ 4 representing a hydrogen atom,
or one of the salts thereof,
so as to realize the substitution of a hydroxyl group of the lignin, in particular of a group borne by a benzylic carbon, by said compound having the general formula (II).

10. The method according to claim 9 , wherein the compound having the general formula (II) is introduced into the reaction medium in a quantity such that the number of molar equivalents of the compound having the general formula (II) with respect to the number of benzylic carbons of the lignin is between 2 and 15.

11. The method according to claim 9 , wherein the reaction between the lignin and the compound having the general formula (II) is carried out in an acidic medium.

12. The method according to claim 9 , wherein the reaction between the lignin and the compound having the general formula (II) is carried out in an organic solvent, alone or in a mixture with water.

13. The method according to claim 9 , implemented on lignocellulosic biomass.

14. The method according to claim 9 , implemented on lignin extracted from lignocellulosic biomass.

15. The method according to claim 9 , implemented simultaneously to a method for extraction of lignin from lignocellulosic biomass.

16. A method for depolymerisation of lignin, comprising the two successive steps of:
implementing a method for preparing a lignin derivative according to claim 9 , and
cracking of the lignin derivative thus obtained.

17. The method according to claim 16 , wherein said two steps are carried out successively in the same reactor.

18. A depolymerisation product obtainable by a method for depolymerisation of lignin according to claim 16 .

Assignees

• Institut National De Rech Pour Lagriculture Lalimentation Et Lenvironnement
• Institut Nat Denseignement Superieur Pour Lagriculture Lalimentation Et Lenvironnement
• Institut National De Rech Pour Lagriculture Lalimentation Et Environnement

Inventors

• Roumeas Laurent
• Billerach Guillaume
• Dubreucq Eric
• Fulcrand Hélène

Classifications

• C07G1/00 Primary

  Low-molecular-weight derivatives of lignin (high-molecular-weight derivatives of lignin {C08H6/00}) · CPC title

• Y02P20/55

  Design of synthesis routes, e.g. reducing the use of auxiliary or protecting groups · CPC title