Process for the bromination of polystyrenes

Claim 2

A process for producing an essentially trihalogenated polystyrene product useful as a flame retardant additive, comprising the following steps: a. dissolving polystyrene having a molecular weight in the range of from about 50,000 to about 750,000, as determined by gel permeation chromatography, in a chlorinated hydrocarbon solvent, at a concentration of from about 5% to about 15% by weight of said polystyrene based on said solvent; b. reacting said polystyrene in said solution with a stoichiometric excess of bromine chloride to produce a tribrominated polystyrene product, under substantially anhydrous conditions at less than 0.02% by weight of H 2 O, based on said solvent, and at a temperature in the range of from about 20° C. to about 50° C., in the presence of a catalytic amount of a Lewis acid of a metal chloride salt having a Lewis acid catalyst artivity substantially equivalent to that of antimony trichloride for a sufficient period of time to permit the reaction to produce a tribrominated polystyrene product.

Claim 3

The process of claim 1 wherein the Lewis acid catalyst is antimony trichloride.

Claim 4

A process for producing an essentially trihalogenated polystyrene product useful as a flame retardant additive, comprising the following steps: a. dissolving polystyrene having a molecular weight in the range of from about 50,000 to about 250,000, as determined by gel permeation chromatography, in a chlorinated hydrocarbon solvent, at a concentration of from about 5% to about 15% by weight of said polystyrene based on said solvent; b. reacting said polystyrene in said solution with a stoichiometric excess of bromine chloride to produce a tribrominated polystyrene product, under substantially anhydrous conditions at less than 0.02% by weight of H 2 O, based on said solvent, and at a temperature in the range of from about 20° C. to about 50° C., in the presence of at least 5% by weight, based on the polystyrene, of a Lewis acid catalyst of a metal chloride salt having a Lewis acid catalyst artivity substantially equivalent to that of antimony trichloride for a sufficient period of time to permit the reaction to produce a tribrominated polystyrene product.

Claim 5

A process for producing an essentially trihalogenated polystyrene product useful as a flame retardant additive, comprising the following steps: a. dissolving polystyrene having a molecular weight in the range of from about 50,000 to about 250,000, as determined by gel permeation chromatography, in a chlorinated hydrocarbon solvent, at a concentration of from about 5% to about 15% by weight of said polystyrene based on said solvent; b. reacting said polystyrene in said solution with a stoichiometric excess of bromine chloride to produce a tribrominated polystyrene product, under substantially anhydrous conditions at less than 0.02% by weight of H 2 O, based on said solvent, and at a temperature in the range of from about 20° C. to about 50° C., in the presence of at least 5% by weight, based on the polystyrene, of a Lewis acid catalyst of a metal chloride salt having a Lewis acid catalyst artivity substantially equivalent to that of antimony trichloride for a sufficient period of time to permit the reaction to produce a tribrominated polystyrene product.

Claim 6

The process of claim 3 wherein the Lewis acid catalyst is antimony trichloride.

Claim 7

A process for producing an essentially trihalogenated polystyrene product useful as a flame retardant additive, comprising the following steps: a. dissolving polystyrene having a molecular weight in the range of from about 50,000 to about 250,000, as determined by gel permeation chromatography, in a chlorinated hydrocarbon solvent, at a concentration of from about 5% to about 15% by weight of said polystyrene based on said solvent; b. reacting said polystyrene in said solution with a stoichiometric excess of bromine chloride to product a tribrominated polystyrene product, under substantially anhydrous conditions at less than 0.02% by weight of H 2 O, based on said solvent, and at a temperature in the range from about 20° C. to about 50° C., in the presence of from about 5% to about 8% by weight, based on the polystyrene, of a Lewis acid catalyst of a metal chloride salt having a Lewis acid catalyst artivity substantially equivalent to that of antimony trichloride for a sufficient period of time to permit the reaction to produce a tribrominated polystyrene product containing at least 65% by weight of bromine.

Claim 8

A process for producing an essentially trihalogenated polystyrene product useful as a flame retardant additive, comprising the following steps: a. dissolving polystyrene having a molecular weight in the range of from about 50,000 to about 250,000, as determined by gel permeation chromatography, in a chlorinated hydrocarbon solvent, at a concentration of from about 5% to about 15% by weight of said polystyrene based on said solvent; b. reacting said polystyrene in said solution with a stoichiometric excess of bromine chloride to product a tribrominated polystyrene product, under substantially anhydrous conditions at less than 0.02% by weight of H 2 O, based on said solvent, and at a temperature in the range from about 20° C. to about 50° C., in the presence of from about 5% to about 8% by weight, based on the polystyrene, of a Lewis acid catalyst of a metal chloride salt having a Lewis acid catalyst artivity substantially equivalent to that of antimony trichloride for a sufficient period of time to permit the reaction to produce a tribrominated polystyrene product containing at least 65% by weight of bromine.

Claim 9

The process of claim 5 wherein the Lewis acid catalyst is antimony trichloride.