Patent US4736030A successfully refreshed from Google Patents.
US4736030A
Expired / Lapsed
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Preparation of 1-alkyl- or 1-cycloalkylpiperazines
Assignee: BASF SE
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Filing: 1985-10-24
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Granted: 1988-04-05
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Expires: 2005-10-24
Abstract
Abstract 1-Alkyl- or 1-cycloalkylpiperazines are prepared by reacting piperazine with an alkanol or cycloalkanol in the presence of hydrogen and a hydrogenation/dehydrogenation catalyst by a process in which the reaction is carried out at from 130° to 190° C. under from 5 to 100 bar in the presence of from 5 to 40% by weight, based on the reaction mixture, of water, and the molar ratio of piperazine to alkanol or cycloalkanol is kept at from 1:1.5 to 1:8.
Inventors
- 👤 Herbert Mueller
- 👤 Dieter Voges
- 👤 Wolfgang Lengsfeld
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:18
CPC Classifications
C; C07; C07D; C07D295/00; C07D295/02; C07D295/023
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
110 words
A process for the preparation of a 1-alkyl-, 1-cycloalkylpiperazine or 1-piperazinly-3-tetrahydrofuranylmethane by reacting piperazine with an alkanol, cycloalkanol or 3-hydroxymethyltetrahydrofuran in the presence of hydrogen and a hydrogenation/hydrogenation catalyst, wherein the reaction is carried out at from 130° to 190° C. and under from 5 to 100 bar in the presence of from 5 to 40% by weight, based on the reaction mixture, of water which is added to the reaction mixture, and in the presence of from 0.01 to 1% by weight, based on the reaction mixture, of an inorganic base, and the molar ratio of piperazine to alkanol, cycloalkanol or 3-hydroxymethyltetrahydrofuran is kept at from 1:1.5 to 1:8.
Claim 2
Dependent Claim
110 words
A process for the preparation of a 1-alkyl-, 1-cycloalkylpiperazine or 1-piperazinly-3-tetrahydrofuranylmethane by reacting piperazine with an alkanol, cycloalkanol or 3-hydroxymethyltetrahydrofuran in the presence of hydrogen and a hydrogenation/hydrogenation catalyst, wherein the reaction is carried out at from 130° to 190° C. and under from 5 to 100 bar in the presence of from 5 to 40% by weight, based on the reaction mixture, of water which is added to the reaction mixture, and in the presence of from 0.01 to 1% by weight, based on the reaction mixture, of an inorganic base, and the molar ratio of piperazine to alkanol, cycloalkanol or 3-hydroxymethyltetrahydrofuran is kept at from 1:1.5 to 1:8.
Claim 3
Dependent Claim
13 words
The process of claim 1, wherein hydrogenation/dehydrogenation catalyst based on nickel is used.
Claim 4
Dependent Claim
16 words
The process of claim 1, wherein an alkanol of 1 to 10 carbon atoms is used.
Claim 5
Dependent Claim
19 words
The process of claim 3, wherein the alkanol is methanol, ethanol, propanol, isopropanol, butanol, isobutanol, hexanol, octanol or 2-ethylhexanol.
Claim 6
Dependent Claim
29 words
The process of claim 1, wherein the inorganic base is selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, calcium hydroxide and calcium oxide.
Claim 7
Dependent Claim
15 words
The process of claim 1, wherein the inorganic base is sodium carbonate or calcium hydroxide.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-04-05 | 1991-10-05 | 1992-04-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-05 | 1995-10-05 | 1996-04-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-05 | 1999-10-05 | 2000-04-05 | $7700.00 | Window Closed / Lapsed |