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Patent US3607686A successfully refreshed from Google Patents.
US3607686A
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Process for the reductive cleavage of sulphonic acid groups from anthraquinone-sulphonic acids
Assignee: Sandoz AG
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Filing: 1969-05-26
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Granted: 1971-09-21
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Expires: 1989-05-26
Abstract
Abstract The invention relates to an electrochemical reductive desulphonation of anthraquinone- Beta sulphonic acids which contain an electron donator as substituent in at least one Alpha -position of the nuclei bearing the sulphonic acid groups.
Inventors
- 👤 Paul Buecheler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:42
CPC Classifications
C; C25; C25B; C25B3/00; C25B3/20; C25B3/25; C25B3/01; C25B3/07; C25B3/09
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
29 words
A process according to claim 1 which consists of electrochemical cleavage of at least one Beta -sulfonic acid group in a position adjacent to an Alpha -substituted electron donator.
Claim 2
Dependent Claim
18 words
A process according to claim 1 wherein each Alpha -substituted electron donator is a hydroxyl or amino group.
Claim 3
Dependent Claim
20 words
A process according to claim 1 which consists of electrochemical desulfonation of a mixture of different anthraquinone- Beta -sulfonic acids.
Claim 4
Dependent Claim
25 words
A process according to claim 1 wherein catholyte for the electrochemical cleavage comprises an aqueous solution of an alkali metal hydroxide or of ammonium hydroxide.
Claim 5
Dependent Claim
40 words
A process according to claim 1, wherein the electrochemical cleavage is carried out on a cathode of coal, tungsten, antimony, gold, nickel tantalum, palladium, silver, tin, zinc, manganese, copper, gallium, cadmium, thallium, lead, mercury, platinum, copper amalgam or lead dioxide.
Claim 6
Dependent Claim
22 words
A process according to claim 1, wherein the electrochemical cleavage is carried out in the temperate range between 10* and 90* C.
Claim 7
Dependent Claim
22 words
A process according to claim 7, wherein the electrochemical cleavage is carried out in the temperature range between 30* and 70* C.
Claim 8
Dependent Claim
14 words
A process according to claim 6 in which the cathode is of copper amalgam.
Claim 9
Dependent Claim
15 words
A process according to claim 1, wherein the voltage is between 1 and 25 volts.
Claim 10
Dependent Claim
15 words
A process according to claim 10 wherein the voltage is between 2.5 and 6 volts.
Claim 11
Dependent Claim
15 words
A process according to claim 10 wherein the voltage is increased during the reductive cleavage.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-20 | 1975-03-22 | 1975-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-20 | 1979-03-22 | 1979-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-20 | 1983-03-22 | 1983-09-21 | $7700.00 | Window Closed / Lapsed |