Patent EP0294651A1 successfully refreshed from Google Patents.
EP0294651A1
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Process for the preparation of (2,2)-paracyclophane
Assignee: Union Carbide Corp
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Filing: 1988-05-25
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Granted: —
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Expires: 2008-05-25
Abstract
Abstract An improved process is provided for the preparation of the dimer, 2,2-paracyclophane, which is useful as the starting material for parylene conformal coatings used in the electronics industry for the protection of various sensitive electronic components. The process comprises optimization of the normally low yield of dimer formed by the Hofmann elimination reaction of p-methylbenzyltrimethylammonium halide by conducting the elimination reaction in the presence of dimethylsulfoxide and certain reaction promoters.
Inventors
- 👤 Chinsoo Lee
- 👤 David Robinson Bassett
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 08:50
CPC Classifications
C; C07; C07C; C07C13/00; C07C13/28; C07C13/32; C07C13/72; C07C1/00; C07C1/32; C07C1/321; C07C1/323; C07C13/70; C07C2603/00; C07C2603/92
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
92 words
An process for the preparation of the 2,2-paracyclophane dimer used in the preparation of parylene, which comprises contacting an aqueous solution of p-methylbenzyltrimethylammonium halide with an alkali hydroxide in the presence of dimethylsulfoxide and at least one reaction promoter selected from a) a methyl alkyleneoxy ether of the formula: CH₃-(-O-CH₂-CH₂-) n -O-(CH₂-CH₂-O) m -CH₃ wherein n is 1 to 18, and m is 0 or 1 to 4, and b) a crown ether have from 4 to 6 oxygen atoms and from 12 to 18 carbon atoms, and thereafter recovering the 2,2-paracyclophane.
Claim 2
Dependent Claim
92 words
An process for the preparation of the 2,2-paracyclophane dimer used in the preparation of parylene, which comprises contacting an aqueous solution of p-methylbenzyltrimethylammonium halide with an alkali hydroxide in the presence of dimethylsulfoxide and at least one reaction promoter selected from a) a methyl alkyleneoxy ether of the formula: CH₃-(-O-CH₂-CH₂-) n -O-(CH₂-CH₂-O) m -CH₃ wherein n is 1 to 18, and m is 0 or 1 to 4, and b) a crown ether have from 4 to 6 oxygen atoms and from 12 to 18 carbon atoms, and thereafter recovering the 2,2-paracyclophane.
Claim 3
Dependent Claim
19 words
The process of claim 1 wherein the reaction is effected in the presence of an inert water-immiscible organic solvent.
Claim 4
Dependent Claim
21 words
The process of claim 2 wherein the solvent is selected from benzene, toluene, para-xylene, ortho-xylene, meta-xylene, hexane, octane, and methylene chloride.
Claim 5
Dependent Claim
13 words
The process of claims 1 to 3 wherein the crown ether is 1,4,7,10,13,16-hexaoxacyclooctadecane.
Claim 6
Dependent Claim
20 words
The process of claims 1 to 4 wherein the methoxyalkenyloxyether is diglyme, preferably 2-methoxyethylether or a tetraglyme, preferably 2-butoxyethyl ether.
Claim 7
Dependent Claim
15 words
The process of claims 1 to 5 wherein the hydroxide is sodium or potassium hydroxide.
References Cited (Backward Citations)
US4532369A
Cited
EP0253191A1
Cited
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