SYNTHESIS OF SHORTER CHAIN POLYOLS

Abstract

Disclosed herein are methods of synthesizing shorter chain polyols. Methods of hydrolyzing polysaccharides are further disclosed. The present invention is also directed towards methods of selectively synthesizing sorbitol.

Claims

1. A method of synthesizing shorter chain polyols comprising: reacting a feed solution comprising at least one component with a high degree of polymerization with hydrogen in the presence of at least one catalyst; wherein a homogeneous mineral acid is not added; thus making at least one shorter chain poloyol.

2. The method of claim 1, wherein the at least one component with a high degree of polymerization is selected from the group consisting of cellulose, polysaccharides, starch, maltodextrin, maltitol, and combinations of any thereof

3. The method of claim 1, wherein the feed solution further comprises a sugar concentration of about 3%.

4. The method of claim 1, wherein the feed solution further comprises a solvent.

5. The method of claim 4, wherein the solvent comprises water.

6. The method of claim 1, wherein the at least one component with a high degree of polymerization is present in the feed solution in an amount greater than about 0.5%.

7. (canceled)

8. The method of claim 1, wherein the at least one catalyst is selected from the group consisting of sponge copper, ruthenium-sulfur supported on carbon, and combinations of any thereof.

9. The method of claim 1, wherein the reacting the feed solution comprising the at least one component with a high degree of polymerization with hydrogen in the presence of the at least one catalyst further comprises: reacting the feed solution comprising the at least one component with a high degree of polymerization with hydrogen in the presence of a first catalyst at a first temperature, thus forming a first product; and reacting the first product in the presence of a second catalyst at a second temperature, thus making the at least one shorter chain polyol.

10. The method of claim 9, wherein the first catalyst consists of Ru-S/C.

11. (canceled)

12. The method of claim 9, wherein the second catalyst consists of copper.

13. (canceled)

14. (canceled)

15. (canceled)

16. The method of claim 1, wherein the at least one shorter chain polyol comprises a compound selected from the group consisting of sorbitol, mannitol, glucitol, dulcitol, 1,2,5,6-hexanetetrol, and combinations of any thereof.

17. The method of claim 1, wherein the at least one component with a high degree of polymerization has a degree of polymerization (DP) number above 3.

18. A method of hydrolyzing polysaccharides, comprising: contacting a feedstock comprising a sugar concentration of about 3% with a catalyst in the presence of hydrogen; wherein the feedstock further comprises at least one component with a degree of polymerization (DP) number above 3; wherein a homogeneous mineral acid is not added; resulting in formation of at least one shorter chain polyol and a decrease in the at least one component with a DP number above 3.

19. The method of claim 18, wherein the feedstock further comprises a compound selected from the group consisting of maltodextrin, soluble cellulose, maltitol, and combinations of any thereof.

20. The method of claim 18, wherein the feedstock further comprises a solvent.

21. (canceled)

22. The method of claim 18, wherein the catalyst is selected from the group consisting of sponge copper, ruthenium-sulfur supported on carbon, and combinations of any thereof

23. (canceled)

24. (canceled)

25. (canceled)

26. (canceled)

27. The method of claim 18 any of claims 18 26, wherein the at least one shorter chain polyol is selected from the group consisting of sorbitol, dulcitol, mannitol, glucitol, 1,2,5,6-hexanetetrol, and combinations of any thereof.

28. A method of selectively synthesizing sorbitol, comprising: contacting a feed solution with a catalyst in the presence of hydrogen; wherein the feed solution comprises a compound selected from the group consisting of soluble cellulose, starch, maltodextrin, maltitol, and combinations of any thereof; wherein a homogeneous mineral acid is not added; thus producing a product with a higher proportion of sorbitol as compared to other compounds formed.

29. (canceled)

30. (canceled)

31. (canceled)

32. The method of claim 28, wherein the product comprises at least 25% sorbitol.

33. The method of claim 28, wherein the product comprises less than about 1% C5 polyols.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 shows a scheme for the synthesis of sorbitol from starch or maltodextrin feed (high degree of polymerization [DP] feed) using a ruthenium-sulfur supported on carbon (Ru-S/C) catalyst and a copper (Cu) catalyst.

[0009] FIG. 2 shows a scheme for DP hydrolysis (hydrolysis of high degree of polymerization compounds, such as maltitol) and sugar hydrogenation (formation of sorbitol and 1,2,5,6-hexanetetrol [HTO]).

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS OF THE INVENTION

[0010] In an illustrative embodiment, a method of the present invention includes synthesizing shorter chain polyols comprising reacting a feed solution comprising at least one component with a high degree of polymerization with hydrogen in the presence of at least one catalyst; wherein a homogeneous mineral acid is not added; thus making at least one shorter chain polyol.

[0011] In another illustrative embodiment, a method of the present invention includes hydrolyzing polysaccharides comprising contacting a feedstock comprising a sugar concentration of about 3% with a catalyst in the presence of hydrogen; wherein the feedstock further comprises at least one component with a degree of polymerization (DP) number above 3; wherein a homogeneous mineral acid is not added; resulting in formation of at least one shorter chain polyol and a decrease in the at least one component with a DP number above 3.

[0012] In yet another illustrative embodiment, a method of the present invention includes selectively producing sorbitol comprising contacting a feed solution with a catalyst in the presence of hydrogen; wherein the feed solution comprises a compound selected from the group consisting of soluble cellulose, starch, maltodextrin, maltitol, and combinations of any thereof; wherein a homogeneous mineral acid is not added; thus producing a product with a higher proportion of sorbitol as compared to other compounds formed.

[0013] In a further embodiment, the at least one component with a high degree of polymerization is selected from the group consisting of cellulose, polysaccharides, starch, maltodextrin, maltitol, and combinations of any thereof In yet a further embodiment, the at least one component with a high degree of polymerization is present in the feed solution in an amount greater than about 0.5%. In still a further embodiment, the at least one component with a high degree of polymerization has a degree of polymerization (DP) number above 3.

[0014] The present invention contemplates various feed solutions and feed stocks. In a further embodiment, the feed solution further comprises a sugar concentration of about 3%. In a further embodiment, the feedstock further comprises a compound selected from the group consisting of maltodextrin, soluble cellulose, maltitol, and combinations of any thereof In yet further embodiments, the feed solution or feedstock further comprise a solvent. In still a further embodiment, the solvent comprises water.

[0015] In a further embodiment, the reacting the feed solution comprising the at least one component with a high degree of polymerization with hydrogen gas in the presence of the at least one catalyst is carried out at a pressure of about 1200 psi. In a further embodiment, the contacting the feedstock comprising a sugar concentration of about 3% with the catalyst in the presence of hydrogen is carried out at a pressure of about 1200 psi. In a further embodiment, the contacting the feed solution with the catalyst in the presence of hydrogen is carried out at a pressure of about 1200 psi.

[0016] The present invention contemplates different catalysts, including sponge copper, Ru-S/C (sulfide-ruthenium supported on carbon), and combinations of any thereof

[0017] In a further embodiment, the reacting the feed solution comprising the at least one component with a high degree of polymerization with hydrogen in the presence of the at least one catalyst further comprises reacting the feed solution comprising the at least one component with a high degree of polymerization with hydrogen in the presence of a first catalyst at a first temperature, thus forming a first product; and reacting the first product in the presence of a second catalyst at a second temperature, thus making the at least one shorter chain polyol. In yet a further embodiment, the first catalyst consists of Ru-S/C. In still a further embodiment, the first temperature is 120 C. In yet a further embodiment, the second catalyst consists of copper. In still a further embodiment, the second temperature is 200 C.

[0018] In a further embodiment, the reacting the feed solution comprising the at least one component with a high degree of polymerization with hydrogen gas in the presence of the at least one catalyst is carried out at a temperature of below about 225 C. In yet a further embodiment, the reacting the feed solution comprising the at least one component with a high degree of polymerization with hydrogen gas in the presence of the at least one catalyst is carried out at a temperature of between about 100 C. and about 223 C. In a further embodiment, the contacting the feedstock comprising a sugar concentration of about 3% with the catalyst in the presence of hydrogen is carried out at a temperature of below about 225 C. In yet a further embodiment, the contacting the feedstock comprising a sugar concentration of about 3% with the catalyst in the presence of hydrogen is carried out at a temperature of between about 100 C. and about 223 C. In a further embodiment, the contacting the feed solution with the catalyst in the presence of hydrogen is carried out at a temperature of below about 225 C. In yet a further embodiment, the contacting the feed solution with the catalyst in the presence of hydrogen is carried out at a temperature of between about 100 C. and about 223 C.

[0019] In a further embodiment, the contacting the feedstock comprising a sugar concentration of about 3% with the catalyst in the presence of hydrogen is carried out by a process selected from the group consisting of a batch process and a continuous process.

[0020] In a further embodiment, the at least one shorter chain polyol comprises a compound selected from the group consisting of sorbitol, mannitol, glucitol, dulcitol, 1,2,5,6-hexanetetrol, and combinations of any thereof.

[0021] In a further embodiment, the product comprises at least 25% sorbitol.

[0022] In a further embodiment, the product comprises less than about 1% CS polyols.

[0023] Referring now to the drawings, various schema are provided for methods of synthesizing shorter chain polyols according to the present invention, for hydrolyzing polysaccharides according to another aspect, and for selectively synthesizing sorbitol according to yet another aspect. Thus, in FIG. 1, a scheme for the synthesis of sorbitol from starch, or at least one component with a high degree of polymerization [DP], feed using a Ru-S/C catalyst and a copper (Cu) catalyst is shown. The starch or at least one component with a high DP feed is reacted in the presence of hydrogen and the Ru-S/C catalyst at 120 C., forming a first product. The first product is then reacted in the presence of the copper catalyst at 200 C., thus producing sorbitol.

[0024] In FIG. 2, a scheme for DP hydrolysis (hydrolysis of at least one component with a high degree of polymerization, such as maltitol) and sugar hydrogenation (formation of 1,2,5,6-hexanetetrol [HTO]) is shown. Maltitol is reacted with hydrogen in the presence of a copper catalyst. Because the catalyst is bi-functional, it can be used for both the hydrolysis and the hydrogenation, resulting in sorbitol and HTO.

[0025] The present invention is more particularly illustrated by the following non-limiting examples:

Example 1

[0026] Aliquots of a feed stock solution containing 3% sugars and 1% compounds with a high DP number (greater than 3) in a solvent (preferably water), H.sub.2 at 1200 psi, and a sponge copper catalyst were combined for reaction in a 1 liter (L) batch reactor at a number of reaction temperatures. The effects that temperature had on the hydrolysis/hydrogenation were tested.

TABLE-US-00001 TABLE 1 Temperature Effects on Hydrolysis/Hydrogenation Sugar C5 Temp conc. polyols Sorbitol DP ( C.) (%) (%) (%) (%) 0 2.88 0.44 25.1 0.8 223 0 0.72 21.7 0 205 0 0.56 25.9 0

TABLE-US-00002 TABLE 2 Temperature Effects on Hydrolysis/Hydrogenation Sugar C5 Temp conc. polyols Sorbitol DP ( C.) (%) (%) (%) (%) 0 2.88 0.42 23.7 0.69 150 0.01 0.47 28.2 0.51 100 2.2 0.43 25.5 0.59

[0027] It was thus determined that sponge copper catalysts can catalyze the hydrolysis of compounds with a high DP number and can reduce sugars to sugar alcohols under a range of temperatures, with good selectivity for producing sorbitol.

Example 2

[0028] Starch (290 g, J. T. Baker), Ru-S/C catalyst (10.0 g), and water (325.0 g) were introduced into a 1 liter (L) stainless steel autoclave reactor, and the reactor was purged with hydrogen gas (800 psi) three times. The reactor was heated to 225 C. with stirring at 1200 rpm. After the reaction, the product was filtered. The filtered water-soluble products were analyzed by high-performance liquid chromatography (HPLC). HTO was produced with high selectivity.

[0029] The present invention has been described with reference to certain examples. However, it will be recognized by those of ordinary skill in the art that various substitutions, modifications, or combinations of any of the examples may be made without departing from the spirit and scope of the invention. Thus, the invention is not limited by the description of the examples, but rather by the appended claims as originally filed.