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US4012280A
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Delignification of lignocellulosic material with an alkaline liquor in the presence of a cyclic keto compound
Assignee: PPG Architectural Coatings Canada Inc
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Filing: 1976-08-30
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Granted: 1977-03-15
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Expires: 1996-08-30
Abstract
Abstract Delignification of lignocellulosic material by treatment with an alkaline liquor in the presence of a cyclic keto compound such as anthraquinone.
Inventors
- 👤 Harry Hutchinson Holton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:20
CPC Classifications
D; D21; D21C; D21C3/00; D21C3/22; D21C3/222
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
123 words
A process for the delignification of lignocellulosic material comprising the steps of 1. treating the lignocellulosic material in a closed reaction vessel with an alkaline pulping liquor containing from 0.001% to 10.0% by weight based on the lignocellulosic material, of a cyclic keto compound selected from the group consisting of naphthoquinone, anthraquinone, anthrone, phenanthrenequinone, the alkyl, alkoxy and amino derivatives of said quinones, 6,11-dioxo-1H-anthra-[1,2-c]pyrazole, anthraquinone-1,2-naphthacridone, 7,12-dioxo-7,12-dihydroanthra[1,2-b]pyrazine 1,2-benzanthraquinone and 10-methylene anthrone, the treatment taking place at a maximum temperature in the range of from 150° C. to 200° C. for a period of 0.5 to 480 minutes, and 2. displacing the pulping liquor from the lignocellulosic material with water or an aqueous liquor inert to the lignocellulosic material to obtain a delignified cellulosic material.
Claim 2
Dependent Claim
123 words
A process for the delignification of lignocellulosic material comprising the steps of 1. treating the lignocellulosic material in a closed reaction vessel with an alkaline pulping liquor containing from 0.001% to 10.0% by weight based on the lignocellulosic material, of a cyclic keto compound selected from the group consisting of naphthoquinone, anthraquinone, anthrone, phenanthrenequinone, the alkyl, alkoxy and amino derivatives of said quinones, 6,11-dioxo-1H-anthra-[1,2-c]pyrazole, anthraquinone-1,2-naphthacridone, 7,12-dioxo-7,12-dihydroanthra[1,2-b]pyrazine 1,2-benzanthraquinone and 10-methylene anthrone, the treatment taking place at a maximum temperature in the range of from 150° C. to 200° C. for a period of 0.5 to 480 minutes, and 2. displacing the pulping liquor from the lignocellulosic material with water or an aqueous liquor inert to the lignocellulosic material to obtain a delignified cellulosic material.
Claim 3
Dependent Claim
48 words
A process as claimed in claim 1 wherein the alkyl quinone derivatives are quinones substituted with one or two alkyl groups each having 1 to 4 carbon atoms and the alkoxy quinone derivatives are quinone substituted with at least one alkoxy group containing 1 to 4 carbon atoms.
Claim 4
Dependent Claim
12 words
A process as claimed in claim 1 wherein the quinone is anthraquinone.
Claim 5
Dependent Claim
29 words
A process as claimed in claim 1 wherein the cyclic keto compounds are selected from the group consisting of anthrone, anthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2,6-dimethylanthraquinone, 2,7-dimethylanthraquinone, 2-amino anthraquinone and 1-methoxyanthraquinone.
Claim 6
Dependent Claim
28 words
A process as claimed in claim 1 wherein the alkaline pulping liquor contains from 0.01% to 1.0% by weight based on lignocellulosic material, of the cyclic keto compound.
Claim 7
Dependent Claim
16 words
A process as claimed in claim 1 wherein the alkaline pulping liquor is a soda liquor.
Claim 8
Dependent Claim
16 words
A process as claimed in claim 1 wherein the alkaline pulping liquor is a kraft liquor.
Claim 9
Dependent Claim
29 words
A process as claimed in claim 7 wherein the kraft liquor contains from 1.0% to 5.0% by weight (based on weight of lignocellulosic material) of polysulphides expressed as sulphur.
Claim 10
Dependent Claim
123 words
A process as claimed in claim 1 wherein the delignified cellulosic material is subjected to the following additional steps: 3. treatment of the delignified cellulosic material in aqueous suspension at a consistency of from 2% to 40% by weight for from 0.5 to 60 minutes at from 20° C. to 90° C. with from 2% to 20% by weight of an alkali metal base and 4. treatment of the alkali treated material in an aqueous medium at a consistency of from 3.0% to 40% by weight with oxygen or an oxygen-containing gas for from 0.5 to 120 minutes at a temperature of from 80° C. to 150° C. and a partial pressure of oxygen of from 20 to 200 pounds per square inch.
Claim 11
Dependent Claim
17 words
A process as claimed in claim 1 wherein the delignified cellulosic material is subjected to conventional bleaching.
Claim 12
Dependent Claim
17 words
A process as claimed in claim 9 wherein the oxygen-treated cellulosic material is subjected to conventional bleaching.
References Cited (Backward Citations)
US3888727A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-03-14 | 1980-09-13 | 1981-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-03-14 | 1984-09-13 | 1985-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-03-14 | 1988-09-13 | 1989-03-15 | $7700.00 | Window Closed / Lapsed |