Anionic polymerization diinitiator and process for preparing same
View Patent ↗Disclosed is an anionic diinitiator prepared using a diisopropenyl benzene compound and an organo lithium compound having primary polymerization sites. The anionic diinitiators are prepared by admixing a diisopropenyl benzene compound with diethyl ether, ethylene, an organo lithium compound, and a solvent under reaction conditions sufficient to prepare a diinitiator having primary lithium alkyl reactive sites. The diinitiators are particularly useful in preparing block copolymers.
1. An anionic polymerization diinitiator prepared by admixing a diisopropenyl benzene compound selected from the group 1,2-diisopropenylbenzene; 1,3-diisopropenylbenzene; 1,4-diisopropenylbenzene; 3,4,5,6 - tetramethyl-1,2-diisopropnenylbenzene; 2,4,5,6-tetraethyl-1,3-diiso-propenylbenzene; 2,3,5,6-tetra-n-hexyl-1,4-diisopropenyl-benzene; 3,4-dicyclohexyl-1,2-diisopropenyl-benezene; 5-(3-methyl-cyclopentyl)-1,3-diiso-propenylbenzene; 3-cyclopentyl-methyl-6-n-propyl-1,4 -diisopropenyl-benzene; 4-(2-cyclo-butyl-1-ethyl)-1,2-diisopropenylbenzene; 3-(2-n-propylcyclopropyl)-1,4-diisopropenylbenzene; 2-methyl-5 -n-hexyl-1,3-diisopropenylbenzene; 4-methyl-1,2-diiso-propenyl-benzene; 5-ethyl-1,3-diisopropenylbenzene; 3-methyl-1,4-diisopropenylbenzene; and mixtures thereof, with diethyl ether, ethylene, an organo lithium compound, and a solvent under reaction conditions sufficient to prepare a diinitiator having primary lithium alkyl reactive sites.
2. The anionic polymerization diinitiator of claim 1 wherein the diisopropenyl benzene compound is 1,3-diisopropenylbenzene.
3. The anionic polymerization diinitiator of claim 1 wherein the organo lithium compound is selected from the group isopropyllithium, sec-butyllithium, tert-octyllithium, tert-butyllithium, and mixtures thereof.
4. The anionic polymerization diinitiator of claim 3 wherein the organo lithium compound is sec-butyl lithium.
5. The anionic polymerization diinitiator of claim 1 wherein the solvent is selected from the group cyclopentane, cyclohexane, hexane, cycloheptane, heptane, benzene, naphthalene, toluene, xylene, tetralin, decalin, dimethyl ether, methylethyl ether, diethyl ether, 1,3-diethoxypropane, tetrahydrofuran and mixtures thereof.
6. The anionic polymerization diinitiator of claim 5 wherein the solvent is cyclohexane.
7. An anionic polymerization diinitiator having the general formula:
wherein R 1 has the general formula:
and R 3 is an aliphatic, cycloaliphatic, aromatic or alkyl-substituted aromatic hydrocarbon radical having from 1 to about 20 carbon atoms, each n is independently an integer having a value from 1 to 10, and R 2 is hydrogen or an alkyl or cycloalkyl radical containing from 1 to 6 carbon atoms.
8. The anionic polymerization diinitiator of claim 7 wherein 3 is an alkyl or cycloalkyl radical containing from 1 to 6 carbon atoms.
9. The anionic polymerization diinitiator of claim 8 having the general formula:
wherein each n is independently an integer having a value of from 1 to 10.
10. A process for preparing an anionic polymerization diinitiator comprising admixing a diisopropenyl benzene compound, diethyl ether, ethylene, an organo lithium compound, and a solvent under reaction conditions sufficient to prepare a diinitiator having primary lithium alkyl reactive sites.
11. The process of claim 10 wherein the diisopropenyl benzene compound is 1,3-diisopropenylbenzene; the organo lithium compound is sec-butyl lithium, and the solvent is cyclohexane.
12. The process of claim 11 wherein the mole ratio of 1,3-diisopropenylbenzene to sec-butyl lithium is from about 0.4:1 to about 0.6:1.
13. The process of claim 12 wherein the mole ratio of 1,3-diisopropenylbenzene to sec-butyl lithium is from about 0.45:1 to about 0.5 5:1.
14. The process of claim 13 wherein the mole ratio of 1,3-diisopropenylbenzene to sec-butyl lithium is about 1:2.
15. The process of claim 11 wherein the molar ratio of diethyl ether to sec-butyl lithium is from about 0.1:1 to about 2:1.
16. The process of claim 15 wherein the molar ratio of diethyl ether to sec-butyl lithium is about 1:1.
17. The process of claim 11 wherein the mole ratio of ethylene to sec-butyl lithium is from about 1:1 to about 10:1.
18. The process of claim 17 wherein the mole ratio of ethylene to sec-butyl lithium is from about 2:1 to about 9:1.
19. The process of claim 18 wherein the mole ratio of ethylene to sec-butyl lithium is from about 5:1 to 8:1.
20. An anionic polymer prepared using the diinitiator of claim 1 .