Patent US3985571A successfully refreshed from Google Patents.
US3985571A
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Process for the production of Berlin blue
Assignee: Evonik Operations GmbH
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Filing: 1975-06-26
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Granted: 1976-10-12
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Expires: 1995-06-26
Abstract
Abstract Berlin blue is produced by converting (a) calcium ferrocyanide, sodium ferrocyanide or magnesium ferrocyanide with (b) an iron II salt at a pH below 7 to an acidic iron II salt of ferrocyanic acid FeH 2 [Fe(CN) 6 ]. The calcium or sodium ions can be washed out of the precipitate of the ferrocyanic salt. The precipitate is treated with (c) an inorganic or organic potassium salt to form Berlin white and then oxidized to Berlin blue. Alternatively, (a), (b) and (c) can be reacted together at a temperature of 20° to 60°C. to form Berlin white directly.
Inventors
- 👤 Helmut Reinhardt
- 👤 Karl Trebinger
- 👤 Gottfried Kallrath
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:40
CPC Classifications
C; C01; C01C; C01C3/00; C01C3/08; C01C3/12; C09; C09C; C09C1/00; C09C1/22; C09C1/26; C01P; C01P2006/00; C01P2006/60
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
88 words
A process comprising reacting in water (a) a member of the group consisting of calcium ferrocyanide, sodium ferrocyanide and magnesium ferrocyanide with (b) a water soluble iron II salt which does not form a water insoluble salt with calcium, magnesium or sodium and (c) with a water soluble potassium salt at a pH below 7 to form Berlin white, said process being carried out in one step in which the reaction of (a), (b) and (c) is carried out simultaneously at a temperature commencing between 20 and 60°C.
Claim 2
Dependent Claim
88 words
A process comprising reacting in water (a) a member of the group consisting of calcium ferrocyanide, sodium ferrocyanide and magnesium ferrocyanide with (b) a water soluble iron II salt which does not form a water insoluble salt with calcium, magnesium or sodium and (c) with a water soluble potassium salt at a pH below 7 to form Berlin white, said process being carried out in one step in which the reaction of (a), (b) and (c) is carried out simultaneously at a temperature commencing between 20 and 60°C.
Claim 3
Dependent Claim
16 words
A process according to claim 1 wherein the ferrocyanide (a) is calcium ferrocyanide or sodium ferrocyanide.
Claim 4
Dependent Claim
23 words
A process according to claim 2 wherein after the initial reaction the temperature is increased to between above 60°C. and the boiling point.
Claim 5
Dependent Claim
15 words
A process according to claim 3 wherein the temperature is increased to the boiling point.
Claim 6
Dependent Claim
15 words
A process according to claim 2 wherein the process is initiated at 30° to 50°C.
Claim 7
Dependent Claim
14 words
A process according to claim 5 wherein the process is initiated at about 40°C.
Claim 8
Dependent Claim
30 words
A process according to claim 2 wherein at least one of (a) and (b) is employed in an amount of 1 to 10 mole % excess of the stoichiometric amount.
Claim 9
Dependent Claim
50 words
A process according to claim 7 wherein the iron II salt is present in the reaction vessel before reaction is begun in an excess of 2 to 6 mole % over the stoichiometrical amount and reactants (a), (b) and (c) are then introduced simultaneously in stoichiometrical amounts into the reactor.
Claim 10
Dependent Claim
50 words
A process according to claim 2 wherein the iron II salt is present in the reaction vessel before reaction is begun in an excess of 2 to 6 mole % over the stoichiometric amount and reactants (a), (b) and (c) are then introduced simultaneously in stoichiometrical amounts into the reactor.
Claim 11
Dependent Claim
17 words
A process according to claim 1 wherein about equivalent amounts of (a), (b) and (c) are employed.
Claim 12
Dependent Claim
13 words
A process according to claim 1 wherein (a) is the sole ferrocyanide employed.
Claim 13
Dependent Claim
15 words
A process according to claim 11 wherein the reactants consist of (a), (b) and (c).
References Cited (Backward Citations)
US2005697A
Cited
US2005698A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-10-12 | 1980-04-12 | 1980-10-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-12 | 1984-04-12 | 1984-10-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-12 | 1988-04-12 | 1988-10-12 | $7700.00 | Window Closed / Lapsed |