US5210341A
Expired / Lapsed
US
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Processes for the preparation of octafluoro-[2,2]paracyclophane
Assignee: Union Carbide Chemicals and Plastics Technology LLC
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Filing: 1991-12-20
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Granted: 1993-05-11
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Expires: 2011-12-20
Abstract
Abstract Processes are disclosed for the preparation of octafluoro-[2,2]paracyclophane which utilize a low temperature, e.g., less than about 200° C., and a reducing agent comprising titanium to promote the dimerization of dihalo-tetrafluoro-p-xylenes. One suitable reducing agent is prepared by combining TiCl 4 with LiAlH 4 in an organic solvent.
Inventors
- 👤 William R. Dolbier, Jr.
- 👤 M. A. Asghar
- 👤 He-Qi Pan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:34
CPC Classifications
C; C07; C07C; C07C17/00; C07C17/26; C07C17/263; C07C17/269; C07C2603/00; C07C2603/92
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
75 words
A process for the preparation of octafluoro-[2,2]paracyclophane, which comprises contacting a dihalo-tetrafluoro-p-xylene with a reducing agent comprising a reduced form of titanium, chloride ions, lithium ions and aluminum ions at a temperature of less than about 200° C. and effective conditions to promote the formation of a reaction product comprising octafluoro-paracyclophane, wherein the yield of octafluoroparacyclophane is at least 20 mole % based on one-half of the moles of dihalo-tetrafluoro-p-xylene contacted with the reducing agent.
Claim 2
Dependent Claim
75 words
A process for the preparation of octafluoro-[2,2]paracyclophane, which comprises contacting a dihalo-tetrafluoro-p-xylene with a reducing agent comprising a reduced form of titanium, chloride ions, lithium ions and aluminum ions at a temperature of less than about 200° C. and effective conditions to promote the formation of a reaction product comprising octafluoro-paracyclophane, wherein the yield of octafluoroparacyclophane is at least 20 mole % based on one-half of the moles of dihalo-tetrafluoro-p-xylene contacted with the reducing agent.
Claim 3
Dependent Claim
26 words
The process of claim 1 wherein the reducing agent is present in an amount of at least 3.0 moles of titanium per mole of the dihalotetrafluoro-p-xylene.
Claim 4
Dependent Claim
20 words
The process of claim 1 wherein the effective conditions include a temperature of from about 20 to about 100° C.
Claim 5
Dependent Claim
20 words
The process of claim 1 wherein the effective conditions include contacting the dihalo-tetrafluoro-p-xylene with the reducing agent under reflux conditions.
Claim 6
Dependent Claim
13 words
The process of claim 1 wherein the effective conditions include an inert atmosphere.
Claim 7
Dependent Claim
15 words
The process of claim 1 wherein the dihalo-tetrafluoro-p-xylene is added gradually to the reducing agent.
Claim 8
Dependent Claim
16 words
The process of claim 1 wherein the titanium has a valence of from 0 to 3.
Claim 9
Dependent Claim
22 words
The process of claim 1 wherein the reducing agent is prepared by combining TiCl 4 and LiAlH 4 in an organic solvent.
Claim 10
Dependent Claim
20 words
The process of claim 1 which further comprises recovering at least a portion of the octafluoro-paracyclophane from the reaction product.
Claim 11
Dependent Claim
34 words
The process of claim 1 wherein the yield of octafluoro-paracyclophane is at least from about 25 to about 35 weight % based on one-half of the moles of dihalo-tetrafluoro-p-xylene contacted with the reducing agent.
Claim 12
Dependent Claim
10 words
The process of claim 1 wherein the dihalo-tetrafluoro-p-xylene is dibromotetrafluoro-p-xylene.
Claim 13
Dependent Claim
45 words
The process of claim 1 wherein the reducing agent is prepared by combining a first mixture comprising TiCl 4 and tetrahydrofuran with a second mixture comprising LiAlH 4 and tetrahydrofuran at conditions effective to provide titanium having a valence state of from 0 to 3.
Claim 14
Dependent Claim
28 words
The process of claim 12 wherein the effective conditions to provide titanium having a valence state of from 0 to 3 include a temperature of about 0° C.
Claim 15
Dependent Claim
25 words
The process of claim 12 wherein the effective conditions to provide titanium having a valence state of from 0 to 3 include an inert atmosphere.
Claim 16
Dependent Claim
18 words
The process of claim 8 wherein the organic solvent is selected from tetrahydrofuran, dioxane, dimethoxyethane and mixtures thereof.
Claim 17
Dependent Claim
97 words
A process for the preparation of octafluoro-paracyclophane, which comprises: (a) gradually adding a mixture of dibromotetrafluoro-p-xylene and tetrahydrofuran to a reducing agent comprising titanium having a valence of 0 to 3, tetrahydrofuran, lithium ions, aluminum ions and chloride ions, under an inert atmosphere and at a temperature less than about 200° C. to form a reaction product comprising octafluoro-paracyclophane, wherein the yield of octafluoro-paracyclophane is at least 20 mole % based on one-half of the moles of dihalotetrafluoro-p-xylene contacted with the reducing agent; and (b) recovering at least a portion of the octafluoro-paracyclophane from the reaction product.
Claim 18
Dependent Claim
97 words
A process for the preparation of octafluoro-paracyclophane, which comprises: (a) gradually adding a mixture of dibromotetrafluoro-p-xylene and tetrahydrofuran to a reducing agent comprising titanium having a valence of 0 to 3, tetrahydrofuran, lithium ions, aluminum ions and chloride ions, under an inert atmosphere and at a temperature less than about 200° C. to form a reaction product comprising octafluoro-paracyclophane, wherein the yield of octafluoro-paracyclophane is at least 20 mole % based on one-half of the moles of dihalotetrafluoro-p-xylene contacted with the reducing agent; and (b) recovering at least a portion of the octafluoro-paracyclophane from the reaction product.
Claim 19
Dependent Claim
16 words
The process of claim 16 wherein the temperature is from about 20 to about 100° C.
References Cited (Backward Citations)
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