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US3681467A Expired / Lapsed US ⏱️ 0.0 years remaining

Bromophenol isomerization

Assignee: Wyeth Holdings LLC
•
Filing: 1968-04-25
•
Granted: 1972-08-01
•
Expires: 1988-04-25
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Abstract

Abstract A process for enriching the ortho bromo isomer content of a phenolic material characterized by the presence of at least one brominated phenol and a bromine content of less than two atoms of bromine for each of phenolic nucleus. The phenolic material may particularly consist of at least one monobrominated and/or dibrominated product of a compound of the formula: WHEREIN R1, R2 and R3 are hydrogen or primary or secondary alkyl groups containing one to four carbon atoms. The process is characterized by isomerization and/or disproportionation of the starting material in the presence of hydrogen bromide and an inert solvent, (such as a chlorinated hydrocarbon or a nitro aromatic hydrocarbon), at a temperature in the range -25* to 60* C. for a period of time sufficient to obtain a high concentration of the desired ortho bromo isomer. The isomerization of the bromination products of m-cresol to obtain 6-bromo-m-cresol is particularly described.

Inventors

  • 👤 Edward John O'bara

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-30 20:33
CPC Classifications
C; C07; C07C; C07C37/00; C07C37/62

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 25 words
A process as defined in claim 1 wherein said solution is in an inert solvent selected from the group con-sisting of chlorinated hydrocarbons and nitrobenzene.
Claim 2
Dependent Claim 33 words
A process as defined in claim 1 including the additional step of stopping the aging step by adding to said solution a basic material to react with the hydrogen bromide in said solution.
Claim 3
Dependent Claim 24 words
A process as defined in claim 3 including the further step of separating the desired ortho-substituted bromophenol from the mixture of products thus obtained.
Claim 4
Dependent Claim 15 words
A process as defined in claim 1 wherein said phenol is m-cresol, xylenol, or phenol.
Claim 5
Dependent Claim 94 words
A process for preparing ortho-substituted bromophenols comprising brominating a phenol of the formula: wherein R1, R2, and R3 are hydrogen or primary or secondary alkyl groups of 1 to 4 carbon atoms, aging a solution in inert solvent of the resultant bromination products with hy-drogen bromide at a temperature in the range of about -25*C. to about 60*C. to increase the proportion of ortho-substi-tuted bromophenols therein, stopping the aging step by add-ing to said solution a basic material to react with the hy-drogen bromide in said solution, and separating the desired ortho-substituted bromophenol therefrom.
Claim 6
Dependent Claim 25 words
A process as defined in claim 6 wherein said bromination step and said aging step are both performed in solution in the same inert solvent.
Claim 7
Dependent Claim 15 words
A process as defined in claim 7 wherein said inert solvent is a chlorinated hydrocarbon.
Claim 8
Dependent Claim 15 words
A process as defined in claim 8 wherein said phenol is m-cresol, xylenol, or phenol.
Claim 9
Dependent Claim 22 words
A process as defined in claim 8 wherein said phenol is m-cresol and wherein 6-bromo-m-cresol is separated in the last step thereof.

References Cited (Backward Citations)

CA784782A Cited
US2716139A Cited
US3293309A Cited
US3449443A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1975-08-01 1976-01-31 1976-08-01 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1979-08-01 1980-01-31 1980-08-01 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1983-08-01 1984-01-31 1984-08-01 $7700.00 Window Closed / Lapsed

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