US4650615A
Expired / Lapsed
US
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Purification of carboxylic acid anhydrides contaminated with halogen or halides
Assignee: Halcon SD Group Inc
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Filing: 1985-07-24
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Granted: 1987-03-17
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Expires: 2005-07-24
Abstract
Abstract Carboxylic acid anhydrides are freed from small amounts of halogen and halide moieties by treatment with a phenyl or an alkyl phosphine.
Inventors
- 👤 Nabil Rizkalla
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 00:29
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/54; C07C51/573; Y; Y02; Y02P; Y02P20/00; Y02P20/50; Y02P20/582
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
55 words
A process for the purification of carboxylic acid anhydrides contaminated with halogen and halide values to reduce the quantity of said values in the anhydrides, which comprises treating said anhydrides with a phenyl or an alkyl phosphine in the absence of copper, zinc, silver, and cadmium or their compounds and distilling to recover said anhydrides.
Claim 2
Dependent Claim
55 words
A process for the purification of carboxylic acid anhydrides contaminated with halogen and halide values to reduce the quantity of said values in the anhydrides, which comprises treating said anhydrides with a phenyl or an alkyl phosphine in the absence of copper, zinc, silver, and cadmium or their compounds and distilling to recover said anhydrides.
Claim 3
Dependent Claim
27 words
A process as defined in claim 1, wherein the carboxylic acid anhydride contains at least 0.001, but at most 1,000, ppm of iodine values expressed as I.
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) | 1990-03-16 | 1990-09-15 | 1991-03-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-16 | 1994-09-15 | 1995-03-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-16 | 1998-09-15 | 1999-03-17 | $7700.00 | Window Closed / Lapsed |