Methods of making levulinic acid and alkyl levulinates from saccharides

Patent metadata

Field	Value
Publication number	US-10125079-B2
Application number	US-201715403751-A
Country	US
Kind code	B2
Filing date	Jan 11, 2017
Priority date	Jan 11, 2017
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

Unique methods have been developed to convert polysaccharides into value-added products, such as levulinic acid and alkyl levulinates. The polysaccharides are heated in the presence of water, an alcohol, and an acid to cleave the polysaccharide, and the resulting monosacchrides or monosaccharide acetals or both are contacted with an acid in the presence of an alcohol at a higher temperature. Useful acids include Brønsted acid catalysts and Lewis acid catalysts including mineral acids, metal halides, immobilized heterogeneous catalysts functionalized with a Brønsted acid group or a Lewis acid group, or combinations thereof.

First claim

What is claimed is:

1. A method of making at least one of levulinic acid, and alkyl levulinate comprising:
heating a polysaccharide to a temperature in a range of about 50° C. to about 120° C. in the presence of water, a first alcohol, and a first acid to cleave the polysaccharide into at least one monosaccharide or monosaccharide acetal or both;
increasing the temperature of the at least one monosaccharide or monosaccharide acetal or both and contacting the at least one monosaccharide or monosaccharide acetal or both with a second acid in the presence of a second alcohol at a temperature in a range of about 100° C. to about 200° C. to form a reaction mixture comprising the at least one of the levulinic acid and the alkyl levulinate; and
wherein there is a temperature difference of at least 10° C. between the temperature at which the polysaccharide is heated and the temperature at which the monosaccharide or monosaccharide acetal or both is contacted.

2. The method of claim 1 wherein the first or second alcohol or both comprises a monofunctional alcohol, a polyol, or both.

3. The method of claim 1 wherein the first and second alcohol are the same.

4. The method of claim 1 wherein the first or second alcohol or both comprises methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 1-hexanol, or combinations thereof.

5. The method of claim 1 wherein the first or second alcohol or both comprises ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 2-methyl-1,3-propylene glycol, butane-1,2-diol, glycerin, or combinations thereof.

6. The method of claim 1 wherein the first or second acid or both comprises a mineral acid, a metal halide catalyst, an immobilized heterogeneous catalyst functionalized with a Brønsted acid group or a Lewis acid group, or combinations thereof.

7. The method of claim 6 wherein the first or second acid or both is the immobilized heterogeneous catalyst functionalized with the Brønsted acid group or the Lewis acid group, and wherein the immobilized heterogeneous catalyst functionalized with the Brønsted acid group or the Lewis acid group comprises at least one of a metal halide, a sulfonic acid, and a sulfamic acid bound to an immobilized support comprising at least one of silica gel, silica, an organic resin, and clay.

8. The method of claim 6 wherein the first or second acid or both is the mineral acid, and wherein the mineral acid comprises HCl, H 2 SO 4 , HNO 3 , H 3 PO 4 , or combinations thereof.

9. The method of claim 1 wherein the first and second acid are the same.

10. The method of claim 1 wherein the polysaccharide is sucrose, raffinose, stachyose, galactose, maltose, cellobiose, mellibiose, cellulose, starch, or combinations thereof.

11. The method of claim 1 wherein the polysaccharide contains an alpha(1→4) acetal linkage, a beta(1→4) acetal linkage, an alpha(1→6) acetal linkage, and combinations thereof.

12. The method of claim 1 wherein the polysaccharide comprises at least one of soy molasses, sorghum juice, beet juice, sugar cane, molasses derived from the purification of beet sugar, and molasses derived from the purification of sugar cane sugar.

13. A method of making at least one of levulinic acid and alkyl levulinate comprising:
heating a polysaccharide to a temperature in a range of about 50° C. to about 120° C. in the presence of water, a first monofunctional alcohol, and a first acid to cleave the polysaccharide into at least one monosaccharide or monosaccharide acetal or both;
increasing the temperature of the at least one monosaccharide or monosaccharide acetal or both and contacting the at least one monosaccharide or monosaccharide acetal or both with a second acid in the presence of a second monofunctional alcohol at a temperature in a range of about 100° C. to about 200° C. to form a reaction mixture comprising the at least one of the levulinic acid and the alkyl levulinate; and
wherein there is a temperature difference of at least 10° C. between the temperature at which the polysaccharide is heated and the temperature at which the monosaccharide or monosaccharide acetal or both is contacted.

14. The method of claim 13 wherein the first or second monofunctional alcohol or both comprises methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 1-hexanol, or combinations thereof.

15. The method of claim 13 wherein at least one of: heating the polysaccharide or contacting the at least one monosaccharide or monosaccharide acetal or both takes place in the further presence of at least one polyol.

16. The method of claim 13 wherein at least one of:
the first and second monofunctional alcohol are the same; and
the first and second acid are the same.

17. The method of claim 13 wherein the first or second acid or both comprises a mineral acid, a metal halide catalyst, an immobilized heterogeneous catalyst functionalized with a Brønsted acid group or a Lewis acid group, or combinations thereof.

18. The method of claim 16 wherein the acid is the immobilized heterogeneous catalyst functionalized with the Brønsted acid group or the Lewis acid group, and wherein the immobilized heterogeneous catalyst functionalized with the Brønsted acid group or the Lewis acid group comprises at least one of a metal halide, a sulfonic acid, and a sulfamic acid bound to an immobilized support comprising at least one of silica gel, silica, an organic resin, and clay.

Assignees

• Battelle Memorial Institute

Inventors

• Benecke Herman P
• Garbark Daniel B

Classifications

• C07C51/00

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

• C07C59/185

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

• C07C67/00 Primary

  Preparation of carboxylic acid esters · CPC title

• C07C69/716

  Esters of keto-carboxylic acids {or aldehydo-carboxylic acids} · CPC title