US4285881A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dioxane removal from ether sulfate
Assignee: Vista Chemical Co
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Filing: 1980-04-07
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Granted: 1981-08-25
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Expires: 2000-04-07
Abstract
Abstract Dioxane impurities in ether sulfates are removed by using a novel steam stripping technique in which water is neither added to nor removed from ether sulfate. This is possible because the chemical potential of water in the vapor phase is kept at the same value as that of water in the solution phase. In this way, thickening and foaming are avoided while dioxane levels can be reduced to below 10 parts per million by weight in a single pass.
Inventors
- 👤 Kang Yang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 01:33
CPC Classifications
C; C07; C07C; C07C303/00; C07C303/42
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
29 words
A method for removal of dioxane from ether sulfates comprising contacting ether sulfates/dioxane mixtures with dioxane-free water vapor at temperatures of from about 25° C. to about 150° C.
Claim 2
Independent Claim
29 words
A method for removal of dioxane from ether sulfates comprising contacting ether sulfates/dioxane mixtures with dioxane-free water vapor at temperatures of from about 25° C. to about 150° C.
Claim 3
Dependent Claim
22 words
A method as described in claim 1 wherein the ether sulfate containing dioxane is contacted as a flowing film by water vapor.
Claim 4
Dependent Claim
22 words
A method as described in claim 2 wherein the contact is carried out for a time sufficient to remove substantially all dioxane.
Claim 5
Dependent Claim
27 words
A method as described in claim 3 wherein the contact is carried out for a period of time ranging from about 10 seconds to about 10 hours.
Claim 6
Dependent Claim
24 words
A method as described in claim 4 wherein the dioxane content of ether sulfates is reduced below about 10 parts per million by weight.
Claim 7
Dependent Claim
19 words
A method as described in claim 1 wherein the ether sulfates are prepared by the sulfation of alcohol ethoxylates.
References Cited (Backward Citations)
USB466304I5
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-08-24 | 1985-02-23 | 1985-08-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-24 | 1989-02-23 | 1989-08-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-24 | 1993-02-23 | 1993-08-25 | $7700.00 | Window Closed / Lapsed |