Tribromostyrene products and process for making them
AssigneeBromine Compounds Ltd.
InventorsNurit Kornberg, David Beneish, Michael Peled
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Abstract
Tribromostyrene (TBS) is produced by the preparation of a TBS precursor, which is .beta.-bromoethyl-tribromobenzene (.beta.-BrBr.sub.3), and the successive elimination of hydrogen bromide from said precursor. The precursor is prepared by selective bromination of phenethyl bromide (.beta.-Br), wherein the molar ratio of bromine to phenethyl bromide is comprised between 2.5 and 3.5, and preferably between 3.1 and 3.3 included; and by adding bromine, after an initial addition, at a controlled molar rate.
Claims16
In a process for the preparation of tribromostyrene by the preparation of a tribromostyrene precursor, which is .beta.-bromoethyl-tribromobenzene and the successive elimination of hydrogen bromide from said precursor, which comprises the preparation of said precursor by selective bromination of phenethyl bromide (.beta.-Br), the improvement which comprises:
- (a) that the molar ratio of bromine to phenethyl bromide ranges between 2.5 and 3.5, and preferably between 3.1 and 3.3 inclusive;
- and
- (b) at least after an amount of bromine ranging between 2 and 3 moles Br.sub.2 per mole of phenethyl bromide has been added, the remaining bromine is added at a controlled molar rate that is not substantially greater than stoichiometrically equivalent to the molar rate of evolution of the hydrogen bromide.
.beta.-bromoethyl-tribromobenzene which is at least 89% pure and contains less than 5% of .beta.-BrBr.sub.2.
Tribromostyrene products, which contain at least 90% of tribromostyrene and are characterized by melting points of at least 60.degree. C. and by high shelf life.
Dependencies are inferred from the claim text.