US3954497A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydrolysis of deciduous wood
Assignee: Sued Chemie AG
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Filing: 1974-11-13
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Granted: 1976-05-04
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Expires: 1994-11-13
Abstract
Abstract A process for the hydrolysis of deciduous wood wherein the hydrolysis is carried out in a first stage with an alkali metal hydroxide solution of concentration less than 4 percent by weight and in a second stage with mineral acid. A resulting product, D-(+)-xylose, can be recovered as such or converted directly to xylitol. The process also provides for the convenient recovery of lignin and cellulose present in the wood.
Inventors
- 👤 Hermann Friese
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:25
CPC Classifications
D; D21; D21C; D21C5/00; C; C13; C13K; C13K13/00; C13K13/002
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
102 words
A process for the hydrolysis of deciduous wood which comprises: a. hydrolyzing deciduous wood with an alkali metal hydroxide solution having a concentration of less than 4 percent by weight, to provide a deciduous wood from which the chemically bound acetic acid therein has been substantially completely removed, said acetic acid being then present in solution as alkali metal acetate; b. recovering the deciduous wood from which the chemically bound acetic acid has been substantially removed; and c. hydrolyzing the deciduous wood of step (b) with a mineral acid to provide a solid residue containing lignin and an acidic solution of D-(+)-xylose.
Claim 2
Dependent Claim
102 words
A process for the hydrolysis of deciduous wood which comprises: a. hydrolyzing deciduous wood with an alkali metal hydroxide solution having a concentration of less than 4 percent by weight, to provide a deciduous wood from which the chemically bound acetic acid therein has been substantially completely removed, said acetic acid being then present in solution as alkali metal acetate; b. recovering the deciduous wood from which the chemically bound acetic acid has been substantially removed; and c. hydrolyzing the deciduous wood of step (b) with a mineral acid to provide a solid residue containing lignin and an acidic solution of D-(+)-xylose.
Claim 3
Dependent Claim
56 words
The process of claim 1 wherein the solid residue containing lignin is separated from the acidic solution of D-(+)-xylose, the residue is extracted with organic solvent to remove the lignin therefrom and the remaining residue is at elevated temperature first treated with alkali metal chlorite, followed by treatment with alkali metal hydroxide solution to provide cellulose.
Claim 4
Dependent Claim
23 words
The process of claim 1 wherein the D-(+)-xylose present in the acid solution of step (c) is recovered therefrom in substantially pure form.
Claim 5
Dependent Claim
42 words
The process of claim 1 wherein the said employed in hydrolysis step (c) is sulphuric acid, the acidic solution of D-(+)-xylose is neutralized with calcium oxide, calcium carbonate or barium carbonate and the xylose is thereafter reduced in situ to provide xylitol.
Claim 6
Dependent Claim
16 words
The process of claim 4 wherein the xylitol is recovered from solution in substantially pure form.
Claim 7
Dependent Claim
15 words
The process of claim 2 wherein the lignin-containing residue is extracted with methanol or acetone.
Claim 8
Dependent Claim
19 words
The process of claim 2 wherein the lignin is recovered from the extract solution thereof in substantially pure form.
Claim 9
Dependent Claim
23 words
The process of claim 1 wherein hydrolysis step (a) is carried out with a solution of sodium hydroxide, potassium hydroxide, or combination thereof.
Claim 10
Dependent Claim
12 words
The process of claim 8 wherein the solution is an aqueous solution.
Claim 11
Dependent Claim
25 words
The process of claim 1 wherein hydrolysis step (a) is carried out with an alkali metal hydroxide solution of less than 3 percent by weight.
Claim 12
Dependent Claim
18 words
The process of claim 10 wherein the alkali metal hydroxide solution is 0.5 to 2 percent by weight.
Claim 13
Dependent Claim
18 words
The process of claim 1 wherein hydrolysis step (a) is carried out in the presence of hydrogen peroxide.
Claim 14
Dependent Claim
28 words
The process of claim 12 wherein the hydrogen peroxide is present in an amount of about 10 percent by weight based on the dry weight of the wood.
Claim 15
Dependent Claim
26 words
The process of claim 1 wherein hydrolysis step (a) is carried out at room temperature up to the boiling point of the alkali metal hydroxide solution.
Claim 16
Dependent Claim
16 words
The process of claim 2 wherein the alkali metal chlorite is sodium chlorite or potassium chlorite.
Claim 17
Dependent Claim
25 words
The process of claim 2 wherein an alkali metal chlorite solution having an alkali metal chlorite concentration up to 12 percent by weight is employed.
Claim 18
Dependent Claim
20 words
The process of claim 16 wherein the alkali metal chlorite concentration of said chlorite solution is 10 percent by weight.
Claim 19
Dependent Claim
27 words
The process of claim 2 wherein an alkali metal chlorite solution having a pH of 3 to 5, at a temperature of 60° to 75°C. is employed.
Claim 20
Dependent Claim
10 words
The process of claim 18 wherein the pH is 3.5.
Claim 21
Dependent Claim
19 words
The process of claim 2 wherein a 2 to 4 percent by weight alkali metal hydroxide solution is employed.
Claim 22
Dependent Claim
14 words
The process of claim 20 wherein a 2.4 percent by weight solution is employed.
Claim 23
Dependent Claim
20 words
The process of claim 2 wherein the treatment with alkali metal hydroxide solution is carried out at 60° to 75°C.
Claim 24
Dependent Claim
38 words
The process of claim 1 wherein the amount of alkali metal hydroxide solution is such as to provide from about 1.33 to 2 mols of alkali metal hydroxide per mol of acetic acid chemically bonded in the wood.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-05-04 | 1979-11-03 | 1980-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-04 | 1983-11-03 | 1984-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-04 | 1987-11-03 | 1988-05-04 | $7700.00 | Window Closed / Lapsed |