US4521336A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing lignosulfonates
Assignee: WESTVACO Corp A CORP OF
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Filing: 1984-04-16
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Granted: 1985-06-04
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Expires: 2004-04-16
Abstract
Abstract Disclosed herein is a process for preparing sulfonated lignins by selectively isolating lignins having molecular weights greater than 5,000 and subsequently reacting the lignin with sodium sulfite and an aldehyde. The resulting sulfonated lignins are useful as dispersants for disperse dyes and vat dyes.
Inventors
- 👤 Peter Dilling
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:34
CPC Classifications
C; C08; C08H; C08H6/00; C09; C09B; C09B67/00; C09B67/0071; C09B67/0084; C09B67/0085; C09B67/0086; D; D06; D06P; D06P1/00; D06P1/44; D06P1/46
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
179 words
In a process for preparing sulfonated lignins which comprises reacting lignin material with an aldehyde and a sulfite, selected from the group consisting of water soluble sulfites and bisulfites, wherein the improvement comprises the steps of (a) selectively isolating the lignin material from alkaline black liquor by reducing the black liquor pH such that all but a negligible amount of the lignins having a molecular weight of 5,000 or less remain in solution with the black liquor, (b) acidifying the lignin material to a pH of from about 1.5 to about 5.0 by washing with sulfuric acid followed by adding water to the lignin material to form a slurry of about 25% solids, (c) adding to the lignin slurry the sulfite and the aldehyde in a sulfite to aldehyde mole ratio of from about 1.1:0.1 to about 2.5:1.0, which addition produces an initial reaction pH of from about 8.0 to about 9.2, and (d) the temperature of reaction is raised from ambient to from about 130° C. to about 175° C. for from about 0.5 to about 12 hours.
Claim 2
Dependent Claim
179 words
In a process for preparing sulfonated lignins which comprises reacting lignin material with an aldehyde and a sulfite, selected from the group consisting of water soluble sulfites and bisulfites, wherein the improvement comprises the steps of (a) selectively isolating the lignin material from alkaline black liquor by reducing the black liquor pH such that all but a negligible amount of the lignins having a molecular weight of 5,000 or less remain in solution with the black liquor, (b) acidifying the lignin material to a pH of from about 1.5 to about 5.0 by washing with sulfuric acid followed by adding water to the lignin material to form a slurry of about 25% solids, (c) adding to the lignin slurry the sulfite and the aldehyde in a sulfite to aldehyde mole ratio of from about 1.1:0.1 to about 2.5:1.0, which addition produces an initial reaction pH of from about 8.0 to about 9.2, and (d) the temperature of reaction is raised from ambient to from about 130° C. to about 175° C. for from about 0.5 to about 12 hours.
Claim 3
Dependent Claim
25 words
The process of claim 1 wherein the lignin material is isolated from the black liquor at a pH ranging from about 9.7 to about 11.0.
Claim 4
Dependent Claim
16 words
The process of claim 2 wherein the pH range is from about 10.0 to about 11.0.
Claim 5
Dependent Claim
18 words
The process of claim 1 wherein the water soluble sulfite is sodium sulfite and the aldehyde is formaldehyde.
Claim 6
Dependent Claim
17 words
The process of claim 4 wherein the mole ratio of sodium sulfite to formaldehyde is about 1.3:0.8.
Claim 7
Dependent Claim
13 words
The process of claim 1 wherein the initial reaction pH is about 8.6.
Claim 8
Dependent Claim
17 words
The process of claim 1 wherein the addition of sulfite and aldehyde is sequential in that order.
Claim 9
Dependent Claim
25 words
The process of claim 1 wherein the reaction temperature is first raised to 70° C. for 1 hour after step (c) and before step (d).
Claim 10
Dependent Claim
23 words
The process of claim 8 wherein the reaction temperature of step (d) is 140° C. and said temperature is maintained for 2 hours.
Claim 11
Dependent Claim
21 words
The process of claim 1 wherein the lignin slurry pH below 5.0 is raised to 5.0 by addition of sodium hydroxide.
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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) | 1988-06-03 | 1988-12-03 | 1989-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-03 | 1992-12-03 | 1993-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-03 | 1996-12-03 | 1997-06-04 | $7700.00 | Window Closed / Lapsed |