US4151207A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparation of 3-methoxy-4-hydroxybenzaldehyde
Assignee: Borregaard Industries Ltd
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Filing: 1977-06-08
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Granted: 1979-04-24
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Expires: 1997-06-08
Abstract
Abstract A process for the production of vanillin, 3-methoxy-4-hydroxy-benzaldehyde comprising ultrafiltrating a waste sulfite liquor to obtain a concentrated lignin-rich fraction, and oxidizing said fraction by convention procedures. Advantages of the process are increased yields of vanillin and reduction or avoidance of scale formation on production equipment.
Inventors
- 👤 Hans Evju
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:19
CPC Classifications
C; C08; C08H; C08H6/00; C07; C07C; C07C45/00; C07C45/27; C07C45/32; Y; Y10; Y10S; Y10S210/00; Y10S210/928
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
99 words
In the process for the production of vanillin by the oxidation of a strongly alkaline lignin-containing waste sulfite liquor and wherein scale is deposited, the improvement comprising the steps of ultrafiltrating said waste liquor, obtaining an enriched lignin-containing fraction having a molecular weight above about 1000 and devoid of other low-molecular weight components, adding an alkaline compound to said enriched fraction to obtain a strongly alkaline enriched fraction, passing oxygen through said enriched fraction at a temperature of about 100°-185° C. to oxidize said enriched fraction, and recovering vanillin from said oxidized fraction, whereby scale deposition is substantially eliminated.
Claim 2
Dependent Claim
99 words
In the process for the production of vanillin by the oxidation of a strongly alkaline lignin-containing waste sulfite liquor and wherein scale is deposited, the improvement comprising the steps of ultrafiltrating said waste liquor, obtaining an enriched lignin-containing fraction having a molecular weight above about 1000 and devoid of other low-molecular weight components, adding an alkaline compound to said enriched fraction to obtain a strongly alkaline enriched fraction, passing oxygen through said enriched fraction at a temperature of about 100°-185° C. to oxidize said enriched fraction, and recovering vanillin from said oxidized fraction, whereby scale deposition is substantially eliminated.
Claim 3
Dependent Claim
37 words
The process of claim 1, wherein the lignin content of said waste liquor prior to oxidation is enriched with lignin by ultrafiltrating said liquor with a filter membrane which retains compounds having a molecular weight above 1,000.
Claim 4
Dependent Claim
37 words
The process of claim 1, wherein the lignin content of said waste liquor prior to oxidation is enriched with lignin by ultrafiltrating said liquor with a filter membrane which retains compounds having a molecular weight above 65,000.
Claim 5
Dependent Claim
33 words
The process of claim 1, wherein said waste liquor prior to oxidation is enriched with lignin having a molecular weight in the range of 1,000-65,000 by ultrafiltrating said liquor with a filter membrane.
References Cited (Backward Citations)
NO127545C
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-04-23 | 1982-10-23 | 1983-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-23 | 1986-10-23 | 1987-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-23 | 1990-10-23 | 1991-04-24 | $7700.00 | Window Closed / Lapsed |