# US 4,391,996 A · 1,1-Dichloro-2,2-bis(hydroxyphenyl)ethylene

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- Number: US 4,391,996 A
- Document ID: US4391996A
- Status: Granted
- Kind: A
- Application number: 06/321,644
- Filed: 1981-11-16
- Granted: 1983-07-05
- Earliest claimed: 1977-02-04
- Assignees: General Electric Company
- Inventors: Cleveland William K. S.; Jimmy L. Webb; Charles M. Orlando
- Web page: https://patentgrep.com/patent/US4391996A

## CPC

- C07C 39/367: polycyclic non-condensed, containing only six-membered aromatic rings as cyclic parts, e.g. halogenated poly-hydroxyphenylalkanes
- C08G 64/045: {containing aliphatic unsaturation}
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

A method is described for dehydrochlorinating 1,1,1-trichloro-2,2-bis(4-hydroxyphenyl)ethane employing a refluxing dipolar aprotic solvent, such as dimethylformamide, containing a lithium halide catalyst to produce a crystalline product consisting essentially of 1,1-dichloro-2,2-bis(4-hydroxyphenyl)ethylene. The crystalline product can be isolated in substantially pure form and converted to a high impact, flame retardant polycarbonate.

## Claims

### Claim 1

A dichloride of the formula, ##STR6## which has a trichloride impurity of the formula ##STR7## which is present in said dichloride at a concentration of less than about 1000 ppm.