US3057923A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for producing isoprene and formaldehyde from 4.4-dimethylmetadioxane
Assignee: IFP Energies nouvelles
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Filing: 1959-09-28
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Granted: 1962-10-09
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Expires: 1979-09-28
Abstract
No abstract record available.
Inventors
- 👤 Hellin Michel
- 👤 Malmaison Rueil
- 👤 Coussemant Fernand
- 👤 Lumbroso Daniel
- 👤 Vesinet Le
- 👤 Servaud Jean-Pierre
- 👤 Alexandre Marcel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:32
CPC Classifications
C; C07; C07C; C07C1/00; C07C1/20; C07C1/247; B; B01; B01J; B01J8/00; B01J8/08; B01J8/10; B01J8/18; B01J8/1845; B01J8/1863; B01J8/24; B01J8/26; B01J8/38; B01J8/384; B01J8/388; C07C45/00; C07C45/56; C07C45/57; C07C45/60; B01J2219/00; B01J2219/18; B01J2219/182; B01J2219/185; C07C2521/00; C07C2521/06; C07C2527/00; C07C2527/14; C07C2527/16; C07C2527/167; C07C2527/173; C07C2527/20; C07C2527/22; C07C2527/224
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
73 words
A PROCESS FOR PRODUCING ISOPRENE AND FORMALDEHYDE COMPRISING THE STEP OF PASSING, AT A TEMPERATURE OF FROM 200 TO 300*C., A MIXTURE OF 4.4-DIMETHYLMETADIOXANE WITH AN INERT DILUENT IN THE VAPOR PHASES THROUGH A CATALYST CONSISTING OF SILICON CARBIDE HAVING A SPECIFIC SURFACE NOT EXCEEDING 100 M.2/GRAM, IMPREGNATED WITH PHOSPHORIC ACID TO SUCH AN EXTENT THAT THE ACID CONTENT OF THE CATALYST IS KEPT WITHIN THE RANGE OF FROM 0.5 TO 60% WEIGHT.
Claim 2
Dependent Claim
73 words
A PROCESS FOR PRODUCING ISOPRENE AND FORMALDEHYDE COMPRISING THE STEP OF PASSING, AT A TEMPERATURE OF FROM 200 TO 300*C., A MIXTURE OF 4.4-DIMETHYLMETADIOXANE WITH AN INERT DILUENT IN THE VAPOR PHASES THROUGH A CATALYST CONSISTING OF SILICON CARBIDE HAVING A SPECIFIC SURFACE NOT EXCEEDING 100 M.2/GRAM, IMPREGNATED WITH PHOSPHORIC ACID TO SUCH AN EXTENT THAT THE ACID CONTENT OF THE CATALYST IS KEPT WITHIN THE RANGE OF FROM 0.5 TO 60% WEIGHT.
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) | 1965-10-08 | 1966-04-09 | 1966-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1969-10-08 | 1970-04-09 | 1970-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1973-10-08 | 1974-04-09 | 1974-10-09 | $7700.00 | Window Closed / Lapsed |