US4376859A
Expired / Lapsed
US
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Process for the preparation of aniline condensation dyestuffs
Assignee: Bayer AG
•
Filing: 1980-12-24
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Granted: 1983-03-15
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Expires: 2000-12-24
Abstract
Abstract Process for the preparation of aniline condensation dyestuffs by reacting aniline and/or an alkylaniline batchwise, in cycles or continuously with nitrobenzene, which can be substituted and/or diazoaminobenzene, with warming and in the presence of a catalyst, characterized in that the reaction mixture is worked up continuously.
Inventors
- 👤 Werner Maurer
- 👤 Johann Zimmer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:39
CPC Classifications
C; C09; C09B; C09B17/00; C09B17/02
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
69 words
In a process for the preparation of an aniline condensation dyestuff by reacting aniline and/or an alkyl aniline, batchwise, in cycles or continuously with nitrobenzene, which can be substituted, and/or diazoaminobenzene, with warming and in the presence of a catalyst, the improvement wherein the reaction mixture is worked up by continuously mixing the same with dilute hydrochloric acid and the dyestuff which has precipitated out is continuously filtered off.
Claim 2
Dependent Claim
69 words
In a process for the preparation of an aniline condensation dyestuff by reacting aniline and/or an alkyl aniline, batchwise, in cycles or continuously with nitrobenzene, which can be substituted, and/or diazoaminobenzene, with warming and in the presence of a catalyst, the improvement wherein the reaction mixture is worked up by continuously mixing the same with dilute hydrochloric acid and the dyestuff which has precipitated out is continuously filtered off.
Claim 3
Dependent Claim
24 words
Process according to claim 1, characterised in that aniline and nitrobenzene are subjected to a condensation reaction in the presence of an iron salt.
Claim 4
Dependent Claim
19 words
A process according to claim 2, wherein the condensation reaction is carried out in the presence of hydrochloric acid.
Claim 5
Dependent Claim
17 words
A process according to claim 1, wherein said dilute hydrochloric acid is hydrochloric acid of 2-10% strength.
Claim 6
Dependent Claim
35 words
Process according to claim 1, characterised in that the dyestuff melt is substantially freed from aniline by spray-drying or distillation under normal pressure or in vacuo, before the melt is mixed with an aqueous medium.
Claim 7
Dependent Claim
26 words
Process according to claim 1, characterised in that mixing is carried out in reactors with effective stirrers or in mixing tubes, mixing nozzles or mixing pumps.
Claim 8
Dependent Claim
40 words
Process according to claim 1, characterised in that the continuous mixing of the dyestuff melt with an aqueous medium is followed by continuous isolation of the dyestuff by filtering off, washing, optionally wet-grinding, optionally filtering off again and optionally drying.
References Cited (Backward Citations)
US1988499A
Cited
US4056530A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-03-14 | 1986-09-13 | 1987-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-03-14 | 1990-09-13 | 1991-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-03-14 | 1994-09-13 | 1995-03-15 | $7700.00 | Window Closed / Lapsed |