Process for selective bromination of para-alkylstyrene/isoolefin copolymers

• US 5,654,379 A
• Filed: 05/31/1995
• Issued: 08/05/1997
• Est. Priority Date: 11/27/1987
• Status: Expired due to Term

• Current Assignee: ExxonMobil Chemical Patents Inc. (Exxon Mobil Corporation)
• Original Assignee: ExxonMobil Chemical Patents Inc. (Exxon Mobil Corporation)
• Inventors: Wang, Hsien-Chang, Powers, Kenneth William
• Primary Examiner(s): TESKIN, FRED M
• Application Number:
  US08/455,904
• Time in Patent Office: 797 Days
• Field of Search: 525/333.4, 525/355, 525/356, 525/376, 522/62, 522/160
• US Class Current: 525/356
• CPC Class Codes: C08F 12/04 containing one ring
• CPC Class Codes: C08F 210/10 Isobutene
• CPC Class Codes: C08F 212/04 containing one ring
• CPC Class Codes: C08F 212/12 Monomers containing a branched unsaturated aliphatic radical or a ring substituted by an alkyl radical
• CPC Class Codes: C08F 212/21 Bromine
• CPC Class Codes: C08F 2500/03 Narrow molecular weight distribution, i.e. Mw/Mn < 3
• CPC Class Codes: C08F 4/52 selected from boron, aluminium, gallium, indium, thallium or rare earths C08F4/14 takes precedence
• CPC Class Codes: C08F 8/00 Chemical modification by after-treatment graft polymers, block polymers, crosslinking with unsaturated monomers or with polymers C08F251/00 - C08F299/00; of conjugated diene rubbers C08C
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C08L 71/123 not modified by chemical after-treatment
• CPC Class Codes: Y02P 20/582 Recycling of unreacted starting or intermediate materials
• CPC Class Codes: Y10S 526/912 Reaction medium purification

Abstract

A process for the bromination of a copolymer of an isoolefin having from 4 to 7 carbon atoms and a para-alkystyrene comprising bromating the copolymer in the presence of bromine and a radical initiator thereby providing a brominated copolymer of the copolymer. The brominated copolymer is substantially free of ring bromine and backbone bromine.

Claims

1. A process for the selective bromination of a copolymer of an isoolefin having from 4 to 7 carbon atoms and a para-alkylstyrene having the formula ##STR68## comprising providing said copolymer and brominating said copolymer in the presence of bromine and a radical initiator so as to provide a brominated copolymer of said isoolefin and said para-alkylstyrene including said para-alkylstyrene as ##STR69## or as a mixture of (1) and (2), wherein R and R'"'"' are independently selected from the group consisting of hydrogen, alkyl , and the primary and secondary alkyl halides, said copolymer being otherwise substantially free of ring bromine or any bromine on the polymer backbone chain.

2. The process of claim 1 wherein R and R'"'"' are independently selected from the group consisting of hydrogen, C₁ to C₅ alkyl, and the C₁ to C₅ alkyl halides.

3. The process of claim 2 wherein said R and R'"'"' comprise hydrogen.

4. The process of claim 3 wherein said isoolefin comprises isobutylene.

5. The process of claim 1 wherein said radical initiator is selected from the group consisting of light and heat.

6. The process of claim 5 wherein said radical initiator comprises light.

7. The process of claim 1 wherein said radical initiator has a half-life of between about five and 2,500 minutes.

8. The process of claim 7 wherein said radical initiator comprises a bis azo compound.

9. The process of claim 8 wherein said bis azo compound is selected from the group consisting of azo bis isobutyronitrile, azo bis (2,4 dimethylvalero) nitrile, azo bis (2-methylbutyro) nitrile, and mixtures thereof.

10. The process of claim 1 including terminating said brominating step before about 60% of said para-alkylstyrene has been brominated.

11. The process of claim 10 including quenching said brominating step prior to the exhaustion of said bromine therein.