US3909365A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of chlorinated phenols of improved color
Assignee: Vulcan Materials Co
•
Filing: 1973-11-09
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Granted: 1975-09-30
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Expires: 1993-11-09
Abstract
Abstract Polychlorinated phenols (e.g., pentachlorophenol) of improved color are made by vacuum distilling polychlorinated phenols containing dark color-forming impurities in the presence of a color inhibitor such as zinc dust or free radical-acting substances (e.g., free radical-acting compounds of the phenol, hydroquinone, organic sulfur derivative, organic phosphite, amine and aldehyde type). Ethylene thiourea or zinc dust appear to offer an optimum combination of improved color, cost and process efficiency and are therefore the preferred color inhibitors. In addition, the chlorodioxin content of the impure pentachlorophenol (generally about) 2,000 p.p.m.) is reduced to a residual chlorodioxin content of less than 25 p.p.m. during distillation.
Inventors
- 👤 Ray C Christena
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 16:19
CPC Classifications
C; C07; C07C; C07C37/00; C07C37/68; C07C37/88; C07C37/70; C07C37/74
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
110 words
A METHOD FOR THE SEPARATION AND RECOVERY OF PENTACHLOROPHENOL FROM DARK COLOR-FORMING IMPURITIES CONTAINED THEREIN COMPRISING THE STEPS OF, A. INTRODUCING INTO A DISTILLAND MIXTUREOF PENTACHLOROPHENOL AND DARK COLOR-FORMING IMPURITIES AN EFFECTIVE AMOUNT OF FROM ABOUT 0.1 TO ABOUT 0.5 PERCENT BY WEIGHT OF THE IMPURITY-CONTAINING PENTACHLOROPHENOL OF A ZOLOR INHIBITOR OF ZINC DUST OR ETHYLENE THIOUREA, B. DISTILLINGTHE RESULTING COLOR INHIBITORCONTAINING DISTILLAND AT A PRESSURE FROM ABOUT 35 TO ABOUT 150 MM. HG AND AT A TEMPERATURE OF ABOUT 195*C. TO ABOUT 220*C. TO SEPARATE PENTACHLOROPHENOL VAPORS THEREFROM AND C. CONDENSING SAID VAPOR TO RECOVER PURIFIED PENTACHLORPHENOL IN AN AMOUNT OF AT LEAST 84 PERCENT OF THE IMPURITY-CONTAINING PENTACHLOROPHENOL.
Claim 2
Independent Claim
110 words
A METHOD FOR THE SEPARATION AND RECOVERY OF PENTACHLOROPHENOL FROM DARK COLOR-FORMING IMPURITIES CONTAINED THEREIN COMPRISING THE STEPS OF, A. INTRODUCING INTO A DISTILLAND MIXTUREOF PENTACHLOROPHENOL AND DARK COLOR-FORMING IMPURITIES AN EFFECTIVE AMOUNT OF FROM ABOUT 0.1 TO ABOUT 0.5 PERCENT BY WEIGHT OF THE IMPURITY-CONTAINING PENTACHLOROPHENOL OF A ZOLOR INHIBITOR OF ZINC DUST OR ETHYLENE THIOUREA, B. DISTILLINGTHE RESULTING COLOR INHIBITORCONTAINING DISTILLAND AT A PRESSURE FROM ABOUT 35 TO ABOUT 150 MM. HG AND AT A TEMPERATURE OF ABOUT 195*C. TO ABOUT 220*C. TO SEPARATE PENTACHLOROPHENOL VAPORS THEREFROM AND C. CONDENSING SAID VAPOR TO RECOVER PURIFIED PENTACHLORPHENOL IN AN AMOUNT OF AT LEAST 84 PERCENT OF THE IMPURITY-CONTAINING PENTACHLOROPHENOL.
Claim 3
Dependent Claim
20 words
The method of claim 1 wherein said impure pentachlorophenol contains chlorodioxins and the purified pentachlorophenol contains lower amounts of chlorodioxins.
Claim 4
Dependent Claim
19 words
The process of claim 1 wherein said impure pentachlorophenol is technical grade pentachlorophenol produced by the chlorination of phenol.
Claim 5
Dependent Claim
16 words
The process of claim 3 wherein said phenol is produced by the decomposition of cumene hydroperoxide.
Claim 6
Dependent Claim
15 words
The process of claim 3 wherein said phenol is produced by the sulfonation of benzene.
References Cited (Backward Citations)
US3029292A
Cited
US2864869A
Cited
US3140318A
Cited
US3029294A
Cited
US3102149A
Cited
US3029293A
Cited
US3437699A
Cited
US3403186A
Cited
US3454654A
Cited
US3760010A
Cited
US3770835A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-29 | 1979-03-31 | 1979-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-29 | 1983-03-31 | 1983-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-29 | 1987-03-31 | 1987-09-30 | $7700.00 | Window Closed / Lapsed |