Eli Lilly and Company

Great Lakes Chemical Corporation

John L Sands

Charles J Paget, Jr

Rastko I Mamuzic

Nicolai A Favstritsky

William Ray Fielding

Robert Joseph Stahl

Robert P Levek

John A Garman

James T Ayres

Robert B McDonald

Gregory Thompson

David L McAllister

The invention relates to a process for the purification of brominated styrenic homo-polymers and co-polymers. The purification process reduces or removes contained aliphatic bromine, and free bromine resulting from the reaction of the brominated reagent with the polystyrene backbone. In addition, the method optionally removes occluded inorganic halide impurities from the polymer. These impurities are considered undesirable due to their adverse effects on thermal aging and stability of the final end use resin formulations.

Process for purifying brominated polystyrene

Highly purified brominated aromatic compounds such as decabromodiphenyl ether, pentabromophenol, and the like may be obtained by grinding the crude brominated product to provide particles predominantly less than about 20 microns in diameter and thereafter heating the crude ground brominated product for a time and at a temperature in order to effect substantial removal of the bromine and hydrogen bromide impurities therefrom. Optionally, the product may be ground a second time after the heating step to optimize product particle size and liberate residual impurities. The foregoing procedure is especially effective where the brominated compound is a thermally stable solid under the conditions of treatment and is substantially free from impurities containing aliphatic and alicyclic hydrocarbon groups.

Process for producing purified brominated aromatic compounds

A process for the perbromination of phenol and diphenyl ether by brominating the corresponding compound in bromine as the sole reaction medium using metal and metal-containing catalysts at an elevated initial reaction temperature of at least about 35.degree. C., preferably at least about 45.degree. C., substantially enhances reaction productivity without adversely affecting product yield or quality.

Perbromination of phenol and diphenyl ether at elevated temperature

Benzimidazolyl, benzothiazolyl and benzoxazolyl ureas and thioureas are employed as immune regulatory agents, as agents capable of altering the immune response in mammals.

N-Heterocyclic ureas as immune regulants

N-heterocyclic ureas as immune regulants

A process for isolating crude pentabromophenol containing occluded bromine and hydrogen bromide as impurities comprising the steps of contacting the crude pentabromophenol with a strong acid such as hydrobromic acid, sulfuric acid, hydrochloric acid and phosphoric acid; heating the mixture in order to remove excess bromine; and recovering of the pentabromophenol, whereby formation of carbonyl-group-containing impurities during isolation is minimized.

Process for the isolation of pentabromophenol

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West Lafayette, IN, United States of America

John L Sands