Patent US3850759A successfully refreshed from Google Patents.
US3850759A
Expired / Lapsed
US
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Purification of partially fluorinated cyclobutanes
Assignee: Individual
•
Filing: 1973-10-23
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Granted: 1974-11-26
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Expires: 1993-10-23
Abstract
Abstract Methyl formate, ethyl formate and propylene oxide are used as entraining agents to separate close-boiling mixtures of partially fluorinated cyclobutanes.
Inventors
- 👤 W Hutchinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:21
CPC Classifications
C; C07; C07C; C07C17/00; C07C17/38; C07C17/383; C07C17/386
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
45 words
A PROCESS OF SEPARATING A CLOSE-BOILING MIXTURE OF PARTIALLY FLUORINATED CYCLOBUTANES CONTAINING 4 TO 6 FLUORINE ATOMS WHICH COMPRISES SUBJECTING SAID MIXTURE TO OZEOTROPIC DISTILLATION IN THE PRESENCE OF AN ENTRAINING AGENT SELECTED FROM THE GROUP CONSISTING OF METHYL FORMATE, ETHYL FORMATE AND PROPYLENE OXIDE.
Claim 2
Dependent Claim
45 words
A PROCESS OF SEPARATING A CLOSE-BOILING MIXTURE OF PARTIALLY FLUORINATED CYCLOBUTANES CONTAINING 4 TO 6 FLUORINE ATOMS WHICH COMPRISES SUBJECTING SAID MIXTURE TO OZEOTROPIC DISTILLATION IN THE PRESENCE OF AN ENTRAINING AGENT SELECTED FROM THE GROUP CONSISTING OF METHYL FORMATE, ETHYL FORMATE AND PROPYLENE OXIDE.
Claim 3
Dependent Claim
23 words
A process in accordance with claim 1 wherein the close-boiling mixture is 1,1,2,2-tetrafluorocyclobutane and 1,1,2,2,3-pentafluorocyclobutane and wherein the entraining agent is ethyl formate.
Claim 4
Dependent Claim
23 words
A process in accordance with claim 1 wherein the close-boiling mixture is 1,1,2,2,3,3-hexafluorocyclobutane and trans-1, 1,2,2,3,4-hexafluorocyclobutane and the entraining agent is methyl formate.
Claim 5
Dependent Claim
23 words
A process in accordance with claim 1 wherein the close-boiling mixture is 1,1,2,2,3,3-hexafluorocyclobutane and trans-1, 1,2,2,3,4-hexafluorocyclobutane and the entraining agent is propylene oxide.
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) | 1977-11-25 | 1978-05-27 | 1978-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-25 | 1982-05-27 | 1982-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-25 | 1986-05-27 | 1986-11-26 | $7700.00 | Window Closed / Lapsed |