US3677938A
Expired / Lapsed
US
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Chromatographic separation with porous silica
Assignee: Produits Chimiques Pechiney Saint Gobain
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Filing: 1970-03-18
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Granted: 1972-07-18
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Expires: 1990-03-18
Abstract
Abstract THIS INVENTION IS ADDRESSED TO THE CHROMATOGRAPHIC SEPARATION PROCESS USING COLUMNS FILLED WITH POROUS SILICA PARTICLES IN WHICH THE POROUS SILICA PARTICLES ARE FORMED BY CALCINATION OF SILICA GEL AT TEMPERATURES WITHIN THE RANGE OF 400-1000*C. WITH THE SILICA GEL CONTAINING FOREIGN ATOMS SUCH AS ALKALI METAL CATIONS AND ACIDIC ANIONS SUCH AS SULFUR, ETC.
Inventors
- 👤 Madeleine A Le Page
- 👤 Albert J De Vries
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 02:38
CPC Classifications
C; C04; C04B; C04B18/00; C04B18/02; C04B18/027; B; B01; B01J; B01J20/00; B01J20/02; B01J20/10; B01J20/103; B01J21/00; B01J23/00; B01J23/02; C01; C01B; C01B33/00; C01B33/113; C01B33/12; C01B33/16
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) | 1975-07-18 | 1976-01-17 | 1976-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-18 | 1980-01-17 | 1980-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-18 | 1984-01-17 | 1984-07-18 | $7700.00 | Window Closed / Lapsed |