US4451675A
Expired / Lapsed
US
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Preparation of alkylidenebis(dibromophenol)
Assignee: Dow Chemical Co
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Filing: 1982-07-16
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Granted: 1984-05-29
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Expires: 2002-07-16
Abstract
Abstract The invention is a process for preparing alkylidenebis(dibromophenol) comprising (a) dissolving alkylidenediphenol in between about 17 and 25 moles of methanol for each mole of alkylidenediphenol wherein the methanol has less than 5 percent by weight of water therein; (b) adding to the solution between about 4.0 and 4.1 moles of bromine per mole of alkylidenediphenol at an elevated temperature; (c) adding water to precipitate the alkylidenebis(dibromophenol) remaining in solution after the addition of the bromine in step (b) is completed; and (d) separating the alkylidenebis(dibromophenol) from the methanol solution.
Inventors
- 👤 Charles T. Bounds
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:52
CPC Classifications
C; C07; C07C; C07C37/00; C07C37/62
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
115 words
A process for preparing alkylidenebis(dibromophenol) comprising (a) dissolving alkylidenediphenol in between about 17 and 25 moles of methanol for each mole of alkylidenephenol wherein the methanol has less than about 5 percent by weight of water therein; (b) adding to the solution between about 4.0 and 4.1 moles of bromine per mole of alkylidenediphenol at an elevated temperature wherein the bromine is added over a time period of less than about 0.5 hours; (c) adding water to precipitate the alkylidenebis(dibromophenol) remaining in solution after the addition of the bromine in step (b) is completed; (d) separating the alkylidenebis(dibromophenol) from the methanol solution wherein the alkylidenebis(dibromophenol) prepared has an APHA color number of 20 or less.
Claim 2
Dependent Claim
115 words
A process for preparing alkylidenebis(dibromophenol) comprising (a) dissolving alkylidenediphenol in between about 17 and 25 moles of methanol for each mole of alkylidenephenol wherein the methanol has less than about 5 percent by weight of water therein; (b) adding to the solution between about 4.0 and 4.1 moles of bromine per mole of alkylidenediphenol at an elevated temperature wherein the bromine is added over a time period of less than about 0.5 hours; (c) adding water to precipitate the alkylidenebis(dibromophenol) remaining in solution after the addition of the bromine in step (b) is completed; (d) separating the alkylidenebis(dibromophenol) from the methanol solution wherein the alkylidenebis(dibromophenol) prepared has an APHA color number of 20 or less.
Claim 3
Dependent Claim
36 words
The process of claim 1 which further includes holding the solution of alkylidenediphenol in methanol at elevated temperatures for up to about 3.0 hours, after the addition of the bromine to the solution has been completed.
Claim 4
Dependent Claim
19 words
The process of claim 1 or 2 which further includes condensing any methanol vaporized and collecting methyl bromide evolved.
Claim 5
Dependent Claim
15 words
The process of claim 1 wherein the addition time is less than about 0.25 hour.
Claim 6
Dependent Claim
19 words
The process of claim 1 which further includes washing the separated alklidenebis(dibromophenol) with a solution of methanol in water.
Claim 7
Dependent Claim
20 words
The process of claim 5 wherein the solution used to wash the alkylidenebis(dibromophenol) is 50 volume percent methanol in water.
Claim 8
Dependent Claim
25 words
The process of claim 1 wherein the methanol in which the alkylidenephenol is dissolved has about 2 percent by weight, or less, of water therein.
Claim 9
Dependent Claim
12 words
The process of claim 1 wherein the temperature is above 50° C.
Claim 10
Dependent Claim
15 words
The process of claim 8 wherein the temperature is between 60° C. and 65° C.
Claim 11
Dependent Claim
27 words
The process of claim 1 wherein, in step (c), water is added until the final molar ratio of water to methanol in the solution is about 1:1.
Claim 12
Dependent Claim
11 words
The process of claim 1 wherein the alkylidenebis(dibromophenol) produced is 4,4'-isopropylidenebis(2,6-dibromophenol).
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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) | 1987-05-29 | 1987-11-28 | 1988-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-29 | 1991-11-28 | 1992-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-29 | 1995-11-28 | 1996-05-29 | $7700.00 | Window Closed / Lapsed |