US3994949A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of aromatic cyanic acid esters
Assignee: Bayer AG
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Filing: 1975-09-16
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Granted: 1976-11-30
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Expires: 1995-09-16
Abstract
Abstract Aromatic cyanic acid esters are obtained by an improved process. Optionally substituted mononuclear phenols or polynuclear phenols optionally interrupted through bridge members such as ##EQU1## and/or divalent hydrocarbon bridges are condensated in form of an aqueous phenolate solution with cyanogen halide dissolved in organic solvents in the presence of catalytic quantities of a tertiary amine in a highly disperse system (two phase boundary reaction). The cyanic acid esters obtained are highly pure and stable.
Inventors
- 👤 Karl-Heinrich Meyer
- 👤 Claus Burkhardt
- 👤 Ludwig Bottenbruch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 21:23
CPC Classifications
C; C07; C07C; C07C261/00; C07C261/02; C07C2601/00; C07C2601/12; C07C2601/14
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
113 words
A process for the production of an aromatic cyanic acid ester corresponding to the formula R -- (OCN).sub.n in which R represents one or more optionally substituted aromatic radicals which are attached to one another through at least one member selected from the group consisting of a direct linkage, ##EQU2## or a divalent hydrocarbon bridge and n is a number from 1 to 5, said process comprising reacting a corresponding aqueous phenolate solution having a phenolate content less than 20% by weight with cyanogen halide dissolved in an organic, water-immiscible solvent in the presence of a catalytic amount of a tertiary amine in a highly disperse system as a two phase boundary reaction.
Claim 2
Dependent Claim
113 words
A process for the production of an aromatic cyanic acid ester corresponding to the formula R -- (OCN).sub.n in which R represents one or more optionally substituted aromatic radicals which are attached to one another through at least one member selected from the group consisting of a direct linkage, ##EQU2## or a divalent hydrocarbon bridge and n is a number from 1 to 5, said process comprising reacting a corresponding aqueous phenolate solution having a phenolate content less than 20% by weight with cyanogen halide dissolved in an organic, water-immiscible solvent in the presence of a catalytic amount of a tertiary amine in a highly disperse system as a two phase boundary reaction.
Claim 3
Dependent Claim
25 words
The process as claimed in claim 1, wherein the reaction is carried out at 0° to 10° C in a neutral or weakly acid pH-range.
Claim 4
Dependent Claim
23 words
The process as claimed in claim 1, wherein an aqueous phenolate solution containing from 3 to 10% by weight of phenolate is used.
Claim 5
Dependent Claim
22 words
The process as claimed in claim 1, wherein the reaction is carried out in the presence of an excess of cyanogen halide.
Claim 6
Dependent Claim
35 words
The process as claimed in claim 1, wherein the reaction is carried out in the presence of 0.01 to 10% by weight of a tertiary amine, based on the total quantity of the phenolic component.
Claim 7
Dependent Claim
12 words
The process as claimed in claim 1, wherein said phenolate is 2,2-bis-(4-hydroxyphenyl)propane.
Claim 8
Dependent Claim
12 words
The process as claimed in claim 1, wherein said phenolate is phenol.
Claim 9
Dependent Claim
12 words
The process as claimed in claim 1, wherein said phenolate is 2,2-bis-(3,5-dichloro-4-hydroxyphenyl)propane.
Claim 10
Dependent Claim
12 words
The process as claimed in claim 1, wherein said phenolate is 1,1-bis-(4-hydroxyphenyl)cyclohexane.
References Cited (Backward Citations)
US3107261A
Cited
US3553244A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-11-30 | 1980-05-31 | 1980-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-11-30 | 1984-05-31 | 1984-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-11-30 | 1988-05-31 | 1988-11-30 | $7700.00 | Window Closed / Lapsed |