US4783561A
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US
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Process for the preparation of halogenated (2,2)-paracyclophanes and mixtures of resultant halogenated (2,2)-paracyclophanes
Assignee: Montedison SpA
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Filing: 1986-10-29
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Granted: 1988-11-08
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Expires: 2006-10-29
Abstract
Abstract There is disclosed a process for the preparation of halogenated (2,2)-paracyclophanes by Hofmann elimination, in an alkaline medium, from p.methylbenzyltrimethylammonium hydroxide halogen-substituted in the nucleus.
Inventors
- 👤 Gian Franco Pregaglia
- 👤 Maurizio A. Beretta
- 👤 Alessandro Malacrida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:17
CPC Classifications
C; C07; C07C; C07C25/00; C07C25/18; C07C25/22; C07C17/00; C07C17/26; C07C17/263
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
66 words
A process for preparing halogenated isomers of (2,2)-paracyclophane by Hofmann elimination, in an alkaline aqueous solution, from p.methylbenzyltrimethylammonium hydroxide halogen-substituted in the nucleus, of formula: ##STR7## in which X is a halogen atom, and n is an integer from 1 to 4, in which the concentration of the alkaline hydroxide in the aqueous solution is maintained lower than 40% by weight during the Hofmann elimination reaction.
Claim 2
Dependent Claim
66 words
A process for preparing halogenated isomers of (2,2)-paracyclophane by Hofmann elimination, in an alkaline aqueous solution, from p.methylbenzyltrimethylammonium hydroxide halogen-substituted in the nucleus, of formula: ##STR7## in which X is a halogen atom, and n is an integer from 1 to 4, in which the concentration of the alkaline hydroxide in the aqueous solution is maintained lower than 40% by weight during the Hofmann elimination reaction.
Claim 3
Dependent Claim
13 words
The process of claim 1, in which X in formula (III) is chlorine.
Claim 4
Dependent Claim
19 words
The process of claim 1, wherein the concentration of the alkaline hydroxide ranges from 25 to 35% by weight.
Claim 5
Dependent Claim
23 words
The process of claim 1, wherein the concentration of the alkaline hydroxide is maintained substantially constant during the course of the Hofmann elimination.
Claim 6
Dependent Claim
31 words
The process of claim 1, wherein p.methylbenzyltrimethylammonium hydroxide halogen-substituted in the nucleus and having general formula (III) is formed in situ by reaction of an alkaline hydroxide on the corresponding halide.
Claim 7
Dependent Claim
26 words
The process of claim 1, in which Hofmann elimination is conducted at a temperature from 50° to 130° C. and for a time of 0.5-20 hours.
Claim 8
Dependent Claim
19 words
The process of claim 6, in which Hofmann elimination is conducted for a time of 0.5 to 10 hours.
Claim 9
Dependent Claim
28 words
Mixtures of isomers of dihalogenated (2,2)-paracyclophanes having a halogen on each ring and a degree of purity higher than 99%, prepared according to the process of claim 1.
Claim 10
Dependent Claim
52 words
A mixture of isomers according to claim 8, having the following composition: 30-50% by weight of 5,12-dichloro-(2,2)-paracyclophane, 10-30% by weight of 5,11-dichloro-(2,2)-paracyclophane, 20-40% by weight of 5,14-dichloro-(2,2)-paracyclophane, and 5-15% by weight of 5,13-dichloro-(2,2)-paracyclophane, wherein the sum of the isomers is equal to 100% and the content of dichloro-derivatives is higher than 99%.
Claim 11
Dependent Claim
52 words
A mixture of isomers according to claim 8, having the following composition: 40-65% by weight of 5,12-dichloro-(2,2)-paracyclophane, 30-55% by weight of 5,14-dichloro-(2,2)-paracyclophane, 1-20% by weight of 5,13-dichloro-(2,2)-paracyclophane, and 0-10% by weight of 5,11-dichloro-(2,2)-paracyclophane, wherein the sum of the isomers is equal to 100% and the content of dichloro-derivatives is higher than 99%.
Claim 12
Dependent Claim
22 words
A mixture of isomers according to claim 8, having the following composition: 65-99% by weight of 5,11-dichloro-(2,2)-paracyclophane, 35-1% by weight of 5,13-dichloro-(2,2)-paracyclophane.
References Cited (Backward Citations)
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| 3.5 Years (Year 4) | 1991-11-08 | 1992-05-09 | 1992-11-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-08 | 1996-05-09 | 1996-11-08 | $3760.00 | Window Closed / Lapsed |
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