Process for halogenation of isomonoolefin/para-alkylstyrene copolymers
AssigneeExxon Chemical Patents Inc.
InventorsDavid Yen-Lung Chung, Neil Frederick Newman
Life of this patent
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Abstract
A process for halogenating a copolymer of a C.sub.4 -C.sub.7 isomonoolefin, eg. isobutylene, and a para-alkylsyrene, e.g., para-methylstyrne, is disclosed. Increased halogenation efficiency is achieved by conducting the reaction under free radical halogenation conditions and in the presence of an oxidizing agent, e.g. hydrogen peroxide, which oxidizes hydrogen halide generated in-situ in the reaction back to free halogen. The oxidizing agent is preferably not added to the reaction medium until after first stage halogenation is substantially completed.
Claims27
A process for halogenating a copolymer of a C.sub.4 to C.sub.7 isomonoloolefin and a para-alkylstyrene comprising contacting said copolymer under free radical halogenation conditions with a halogenating agent and hydrogen peroxide, and recovering the halogenated copolymer containing at least about 0.05 mole % of haloalkyl groups.
A process for halogenating a copolymer of a C.sub.4 to C.sub.7 isomonoolefin and a para-alkyl styrene comprising:
- a) contacting said copolymer with a halogenating agent and an organic free radical initiator under free radical halogenation conditions to form a reaction product mixture containing a partially halogenated copolymer and in-situ generated hydrogen halide;
- b) contacting said reaction product mixture from step (a) with an oxidizing agent capable of converting said hydrogen halide to free halogen;
- and
- c) continuing said halogenation until a halogenated copolymer containing at least about 0.05 mole % of haloalkyl groups is obtained.
A multi stage process for brominating a copolymer of a C.sub.4 to C.sub.7 isomonoloefin and a para-alkylstyrene comprising:
- a) forming a solution of said copolymer in organic solvent in a first reactor zone;
- b) contacting said solution with elemental bromine and an organic free radical initiator under free radical bromination conditions to form a reaction product mixture comprising a partially brominated copolymer and an in-situ generated hydrogen bromide;
- c) transferring said reaction product mixture to a second reactor zone and contacting said mixture with an oxidizing agent capable of converting said hydrogen bromide to free bromine;
- and
- d) continuing said bromination in said second reactor zone until a brominated copolymer containing at least about 0.05 mole % of bromoalkyl groups is obtained.
Dependencies are inferred from the claim text.