Patent US1905193A successfully refreshed from Google Patents.
Patent US3816268A successfully refreshed from Google Patents.
US3816268A
Expired / Lapsed
US
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Stabilized distillation of pentachlorophenol
Assignee: Dow Chemical Co
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Filing: 1973-04-20
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Granted: 1974-06-11
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Expires: 1993-04-20
Abstract
Abstract Purified pentachlorophenol is recovered in good yield by distilling the commercially available grade in the presence of a high boiling amine or alkanolamine under reduced pressure and preferably after the starting pentachlorophenol has been exposed to moisture. The purified product is nearly colorless and nonblooming and it is essentially free of polychlorinated dibenzo-p-dioxins and phenoxy-phenols.
Inventors
- 👤 W Watson
- 👤 E Kobel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 04:45
CPC Classifications
C; C07; C07C; C07C37/00; C07C37/68; C07C37/88; C07C37/70; C07C37/74
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
19 words
The process of claim 1 wherein about 0.05-2 percent by weight of amine is present in the distillation mixture.
Claim 2
Dependent Claim
20 words
The process of claim 1 wherein the amine has a boiling point at atmospheric pressure of at least about 170*C.
Claim 3
Dependent Claim
13 words
The process of claim 1 wherein the impure pentachlorophenol is contacted with water.
Claim 4
Dependent Claim
15 words
The process of claim 1 wherein the distillation pressure is below 100 mm. Hg absolute.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-10 | 1977-12-10 | 1978-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-10 | 1981-12-10 | 1982-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-10 | 1985-12-10 | 1986-06-11 | $7700.00 | Window Closed / Lapsed |