Patent US3925424A successfully refreshed from Google Patents.
US3925424A
Expired / Lapsed
US
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Process for preparing 4-chloroformyl phthalic acid anhydride
Assignee: Individual
•
Filing: 1972-03-08
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Granted: 1975-12-09
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Expires: 1992-03-08
Abstract
Abstract A method for preparing 4-chloroformyl phthalic acid anhydride which comprises contacting a trimellitic acid anhydride with an aromatic trichloromethyl compound of the formula:
Inventors
- 👤 Paul Riegger
- 👤 Hermann Richtzenhain
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:37
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/58; C07C51/60
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
24 words
A METHOD FOR PREPARING A 4-CHLOROFORMYL PHTHALIC ACID ANHYDRIDE WHICH COMPRISES CONTACTING A TRIMELLITIC ACID ANHYDRIDE WITH AN AROMATIC TRICHLOROMETHYL COMPOUND OF THE FORMULA:
Claim 2
Independent Claim
24 words
A METHOD FOR PREPARING A 4-CHLOROFORMYL PHTHALIC ACID ANHYDRIDE WHICH COMPRISES CONTACTING A TRIMELLITIC ACID ANHYDRIDE WITH AN AROMATIC TRICHLOROMETHYL COMPOUND OF THE FORMULA:
Claim 3
Dependent Claim
13 words
A process according to claim 1 wherein R is a mononuclear aromatic radical.
Claim 4
Dependent Claim
15 words
A process according to claim 1 wherein a is an integer not greater than 2.
Claim 5
Dependent Claim
14 words
A process according to claim 1 wherein said temperature is between 110* and 150*C.
Claim 6
Dependent Claim
32 words
A process according to claim 1 wherein the ferric chloride is present in an amount between about 0.01 and 1 weight percent based on the weight of the trimellitic acid anhydride reactant.
Claim 7
Dependent Claim
15 words
A process according to claim 3 wherein trimellitic acid anhydride is reacted with 1,4-bis-(trichloromethyl) benzene.
Claim 8
Dependent Claim
14 words
A process according to claim 3 wherein benzotrichloride is contacted with trimellitic acid anhydride.
Claim 9
Dependent Claim
21 words
A process according to claim 1 wherein the reaction is carried out in the presence of terephthalic acid dichloride as solvent.
Claim 10
Dependent Claim
10 words
A process according to claim 1 wherein a is 2.
Claim 11
Dependent Claim
23 words
A process according to claim 1 wherein said aromatic trichloromethyl compound is selected from the group consisting of 1,4-bis-(trichloromethyl)-benzene, 1,3-bis-(trichloromethyl)-benzene, and 1,3,5-tri-(trichloromethyl) benzene.
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) | 1978-12-08 | 1979-06-09 | 1979-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-08 | 1983-06-09 | 1983-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-08 | 1987-06-09 | 1987-12-09 | $7700.00 | Window Closed / Lapsed |