Process for selective bromination of para-alkylstyrene/isoolefin copolymers

• US 5,959,049 A
• Filed: 02/13/1997
• Issued: 09/28/1999
• Est. Priority Date: 05/27/1988
• Status: Expired due to Term

• Current Assignee: Exxon Chemical Patents Inc. (Exxon Mobil Corporation)
• Original Assignee: Exxon Chemical Patents Inc. (Exxon Mobil Corporation)
• Inventors: Wang, Hsien-Chang, Powers, Kenneth William
• Primary Examiner(s): TESKIN, FRED M
• Application Number:
  US08/799,727
• Time in Patent Office: 957 Days
• Field of Search: 526/185, 526/293, 526/347, 526/912, 526/135, 526/196, 526/237, 526/348.7, 525/333.4, 525/356, 525/355, 522/160, 522/150
• US Class Current: 526/185
• 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 producing a copolymer of isoolefin having between 4 and 7 carbon atoms and para-alkylstyrene is provided. The process comprises admixing the isoolefin and the para-alkylstyrene in a copolymerization reactor under copolymerization conditions in the presence of a diluent, and a Lewis Acid catalyst, and maintaining the copolymerization reactor substantially free of impurities which can complex with the catalyst or copolymerize with the isoolefin or the para-alkylstyrene.

Claims

1. A process for producing a copolymer of isoolefin having between 4 and 7 carbon atoms and para-alkylstyrene which comprises admixing said isoolefin and said para-alkylstyrene in a copolymerization reactor under copolymerization conditions in the presence of a diluent, and a Lewis Acid catalyst, and maintaining said copolymerization reactor substantially free of impurities which can complex with said catalyst or copolymerize with said isoolefin or said para-alkylstyrene.

2. The process of claim 1 wherein said copolymerization conditions include a temperature of less than about 0°

C.

3. The process of claim 1 wherein said catalyst is selected from the group consisting of ethyl aluminum dichloride, diethyl aluminum chloride, and mixtures thereof.

4. The process of claim 1 wherein said copolymer is insoluble in said diluent, whereby said process comprises a slurry polymerization process.

5. The process of claim 1 wherein said copolymer is soluble in said diluent, whereby said process comprises a solution polymerization process.

6. The process of claim 1 wherein said copolymer is only slightly soluble in said diluent so as to provide a second phase containing substantially all of said copolymer, whereby said process comprises a cement suspension polymerization process.

7. The process of claim 1 wherein said isoolefin comprises isobutylene and said para-alkylstyrene comprises para-methylstyrene.

8. The process of claim 7 wherein said isobutylene and said para-methylstyrene are present in said copolymer in amounts such that isobutylene comprises from about 80 to 99.5 weight percent of said mixture and said para-methylstyrene comprises from about 0.5 to 20 weight percent of said mixture.

9. The process of claim 7 wherein said isobutylene and said para-methylstyrene are present in said copolymer in amounts such that said mixture comprises from about 10 to 99.5 weight percent of said isobutylene and from about 0.5 to 90 weight percent of said para-methylstyrene.

10. The process of claim 1 wherein said diluent is selected from the group consisting of the aliphatic and aromatic hydrocarbons and the C₁ to C₆ halogenated hydrocarbons and mixtures thereof.

11. The process of claim 1 including subsequently halogenating said copolymer.

12. The process of claim 11 wherein said halogenating comprises photochemical initiation.

13. The process of claim 12 wherein said photochemical halogenation comprises light irradiation of said copolymer in the presence of halogen.

14. The process of claim 11 wherein said halogenation comprises contacting said copolymer with said halogen in the presence of a free radical initiator.

15. The process of claim 13 wherein said halogen comprises bromine.