US3852160A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Distillation of pentachlorophenol with salicylaldehyde and water
Assignee: Dow Chemical Co
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Filing: 1973-05-23
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Granted: 1974-12-03
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Expires: 1993-05-23
Abstract
Abstract Purified pentachlorophenol is recovered in good yield by distilling the commercially available grade in the presence of salicylaldehyde and water under reduced pressure. The purified product is nearly colorless and nonblooming and it is essentially free of polychlorinated dibenzo-p-dioxins and phenoxyphenols.
Inventors
- 👤 W Watson
- 👤 E Kobel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 03:59
CPC Classifications
C; C07; C07C; C07C37/00; C07C37/68; C07C37/70; C07C37/74; C07C37/88
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
43 words
A PROCESS FOR PURIFYING IMPURE PENTACHLOROPHENOL WHICH COMPRISES DISTILLING SAID PENTACHLOROPHENOL AT SUBATMOSPHERIC PRESSURE IN THE PRESENCE OF CONTACTING WATER AND ABOUT 0.05-2 PERCENT OF SALICYLALEHYDE BASED ON THE WEIGHT OF PENTACHLOTROPHENOL, THEREBY SEPARATING PURIFIED PENTACHLOROPHENOL AS A DISTILLATE FROM HIGHER BOILING IMPUTRITIES.
Claim 2
Dependent Claim
43 words
A PROCESS FOR PURIFYING IMPURE PENTACHLOROPHENOL WHICH COMPRISES DISTILLING SAID PENTACHLOROPHENOL AT SUBATMOSPHERIC PRESSURE IN THE PRESENCE OF CONTACTING WATER AND ABOUT 0.05-2 PERCENT OF SALICYLALEHYDE BASED ON THE WEIGHT OF PENTACHLOTROPHENOL, THEREBY SEPARATING PURIFIED PENTACHLOROPHENOL AS A DISTILLATE FROM HIGHER BOILING IMPUTRITIES.
Claim 3
Dependent Claim
21 words
The process of claim 1 wherein about 0.1-1 percent of salicylaldehyde and at least about 0.01 percent of water are present.
Claim 4
Dependent Claim
15 words
The process of claim 2 wherein the distillation pressure is below 100 mm. Hg absolute.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-02 | 1978-06-03 | 1978-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-02 | 1982-06-03 | 1982-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-02 | 1986-06-03 | 1986-12-03 | $7700.00 | Window Closed / Lapsed |