Treatment of epoxidized unsaturated isoolefin copolymers
A process for producing a crosslinked polymer involves contacting an epoxidized unsaturated isoolefin copolymer with a catalytic amount of an acid in an absence of a solvent. A process for producing a hydroxylated unsaturated isoolefin copolymer involves contacting an epoxidized unsaturated isoolefin copolymer with a catalytic amount of an acid in an absence of a solvent. A hydroxylated unsaturated isoolefin copolymer having hydroxyl groups in endo configurations may be produced thereby.
1. A process for producing a crosslinked polymer, the process comprising steps of:
contacting an epoxidized unsaturated isoolefin copolymer with a catalytic amount of an acid in an absence of a solvent, and
crosslinking the epoxidized unsaturated isoolefin copolymer in the presence of the acid.
2. The process according to claim 1 , wherein the acid has a pKa of about 1 or lower.
3. The process according to claim 2 , wherein the crosslinking is performed at a temperature of about 20° C. to about 100° C.
4. The process according to claim 2 , wherein the acid comprises a sulfonic acid optionally wherein the sulfonic acid is p-toluenesulfonic acid.
5. The process according to claim 1 , wherein the acid has a pKa of greater than about 1.
6. The process according to claim 5 , wherein the cross-linking is performed at a temperature of about 160° C. to about 250° C.
7. A process for producing a hydroxylated unsaturated isoolefin copolymer, the process comprising a step of:
contacting an epoxidized unsaturated isoolefin copolymer with a catalytic amount of an acid in an absence of a solvent, wherein the epoxidized unsaturated isoolefin copolymer is hydroxylated in the presence of the acid.
8. The process according to claim 7 , wherein the acid has a pKa of greater than about 1.
9. The process according to claim 8 , wherein the epoxidized unsaturated isoolefin copolymer is hydroxylated at a temperature of about 60° C. to about 180° C.
10. The process according to claim 5 , wherein the acid comprises a compound of formula (I):
where R 1 , R 2 , R 3 , R 4 and R 5 are independently hydrogen, methyl, ethyl, phenyl, chloro or bromo or in one embodiment wherein one of R 1 , R 2 , R 3 , R 4 and R 5 is chloro and four of R 1 , R 2 , R 3 , R 4 and R 5 are hydrogen.
11. The process according to claim 5 , wherein the acid comprises a compound of formula (II):
where R 6 is hydrogen, methyl, ethyl, propyl, butyl, pentyl or hexyl.
12. The process according to claim 5 , wherein the acid is produced in situ with production of the epoxidized unsaturated isoolefin copolymer in an absence of a solvent.
13. The process according to claim 1 , wherein the catalytic amount is about 0.01-10 phr.
14. The process according to claim 1 , wherein the isoolefin copolymer comprises repeating units derived from at least one isoolefin monomer and repeating units derived from at least one multiolefin monomer.
15. The process according to claim 14 , wherein the isoolefin monomer comprises isobutene and/or wherein the at least one multiolefin monomer comprises isoprene.
16. The process according to claim 1 , wherein
the catalytic amount is about 0.01-10 phr;
if the acid has a pKa of about 1 or lower, the contacting is performed at a temperature of about 25° C. to about 60° C.; and
if the acid has a pKa of greater than about 1, the contacting is performed at a temperature of about 160° C. to about 200° C.
17. The process according to claim 1 , wherein:
the acid comprises a compound of formula (II):
wherein R 6 is hydrogen, methyl, ethyl, propyl, butyl, pentyl or hexyl; and
the isoolefin copolymer comprises repeating units derived from isobutylene, and repeating units derived from isoprene.
18. The process according to claim 1 , wherein the process includes forming a hydroxylated unsaturated isoolefin copolymer comprising hydroxyl groups in endo configurations as an intermediate.
19. A process for producing a crosslinked polymer, the process comprising contacting an epoxidized unsaturated isoolefin copolymer with a catalytic amount of an acid in an absence of a solvent;
wherein
the acid has a pKa of greater than about 1 and the contacting is performed at a temperature of about 160° C. to about 250° C.
20. The method of claim 7 , wherein the isoolefin copolymer comprises repeating units derived from at least one isoolefin monomer and repeating units derived from at least one multiolefin monomer, optionally wherein the at least one isoolefin monomer comprises isobutene and/or wherein the at least one multiolefin monomer comprises isoprene.