Patent US3718732A successfully refreshed from Google Patents.
US3718732A
Expired / Lapsed
US
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Method of recovering chemical values from a formate-sodium hydrosulfite reaction mixture
Assignee: Hoechst Celanese Chemical Co
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Filing: 1971-01-13
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Granted: 1973-02-27
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Expires: 1991-01-13
Abstract
Abstract METHOD OF RECOVERING CHEMICAL VALUES FROM A WASTE EFFLUENT SUCH AS A FORMATE-SODIUM HYDROSULFITE REACTION MEDIUM AFTER REMOVAL OF THE SODIUM HYDROSULFITE. THE METHOD ELIMINATES FROM THE REACTION MEDIUM RESIDUE THOSE REDUCING AGENTS WHICH CREATE A CHEMICAL OXYGEN DEMAND IN ANY BODY OF WATER INTO WHICH THEY MIGHT BE DISCHARGED. THE METHOD INCLUDES: INTRODUCING SULFURIC ACID INTO THE REACTION MEDIUM; BOILING TO EXPEL SULFUR DIOXIDE, CONTINUING BOILING AND DISTILLING WITH REFLUX OF METHYL ALCOHOL AND METHYL FORMATE; FILTERING THE REACTION MEDIUM RESIDUE TO REMOVE SULFUR; AND SEPARATING THE RESIDUE SALT FROM WATER AFTER REMOVING OF SULFUR.
Inventors
- 👤 C Winslow
- 👤 J Plentovich
- 👤 M Kise
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:03
CPC Classifications
C; C01; C01D; C01D5/00; C01D5/02; C01B; C01B17/00; C01B17/02; C01B17/06; C01B17/48; C01B17/64; C01B17/66
Claims Analysis
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References Cited (Backward Citations)
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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) | 1976-02-27 | 1976-08-28 | 1977-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-27 | 1980-08-28 | 1981-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-27 | 1984-08-28 | 1985-02-27 | $7700.00 | Window Closed / Lapsed |