# US 4,393,009 A · Process for the preparation of aromatic dicarboxylic acid dichlorides

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- Number: US 4,393,009 A
- Document ID: US4393009A
- Status: Granted
- Kind: A
- Application number: 06/280,898
- Filed: 1981-07-06
- Granted: 1983-07-12
- Earliest claimed: 1979-07-03
- Assignees: Bayer Aktiengesellschaft
- Inventors: Dieter Freitag; Ludwig Bottenbruch; Claus Wulff
- Web page: https://patentgrep.com/patent/US4393009A

## CPC

- B01J 31/0237: {Amines}
- B01J 31/0247: {Imides, amides or imidates (R-C=NR(OR))}
- C07C 51/60: by conversion of carboxylic acids or their anhydrides {or esters, lactones, salts} into halides with the same carboxylic acid part
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

Process for the preparation of pure aromatic dicarboxylic acid dichlorides which comprises reacting an aromatic dicarboxylic acid or an aromatic dicarboxylic acid mixture with phosgen in one stage and in the presence of an N--C.sub.1 --C.sub.6 -alkyl-pyrrolidine, -piperidine or -morpholine as a catalyst and optionally in a solvent or diluent.

## Claims

### Claim 1

A process for preparing an aromatic dicarboxylic acid dichloride which comprises reacting at least one aromatic dicarboxylic acid selected from the group consisting of isophthalic acid and terephthalic acid in one stage with phosgene in the presence of a solvent or diluent and at a temperature of 110.degree. to 180.degree. C. in the presence of 0.2 to 3% by weight, based on said aromatic dicarboxylic acid, of an N-alkylpiperidine, N-alkyl-pyrrolidine or N-alkyl-morpholine, each said alkyl moiety having 1 to 6 carbon atoms.

### Claim 2 (depends on 1)

The process of claim 1 wherein said solvent or diluent is the aromatic dicarboxylic acid dichloride formed during the reaction, a mixture of aromatic dicarboxylic acid dichlorides formed during the reaction, an aliphatic or aromatic hydrocarbon, a halogen substituted aliphatic hydrocarbon or a saturated aliphatic ether.