Polymerization Catalyst System and Process to Produce Highly Reactive Polyisobutylene

Abstract

The present invention provides a method for producing highly reactive polyisobutylene by liquid phase polymerization of isobutylene or isobutylene containing feed stock, wherein at least 70 mole % of polymer chains in the polyisobutylene have exo olefin end groups. Further, the present invention provides a catalyst composition for polymerization, comprising of a Lewis acid complexed with at least two Lewis bases selected from sterically hindered ether and linear dialkyl ether; or a Lewis base complexed with at least two Lewis acids selected from aluminium halides mixture. The present invention additionally provides that Lewis acid with Lewis bases mixture or Lewis base with Lewis acids mixture constituting the catalyst show synergistic effect resulting in high isobutylene conversion and production of polyisobutylene having high exo olefin content, while maintaining desired molecular weight range of 250-10000 Dalton.

Claims

1. A polymerization catalyst system for liquid phase polymerization of isobutylene or an isobutylene containing feed stock for producing highly reactive polyisobutylene, the catalyst system comprising: one or more Lewis acids, one or more Lewis bases, and optionally one or more initiators, wherein the catalyst system is a complex of a Lewis acid with a mixture of Lewis bases, or a complex of a Lewis base with a mixture of Lewis acids; and wherein the polyisobutylene comprises homo or copolymers of isobutylene with at least 70 mole % of polymer chains in the polyisobutylene having exo olefin end groups.

2. The polymerization catalyst system as claimed in claim 1, wherein the Lewis acid is
MR.sub.mX.sub.n  (Formula I) wherein M is selected from a group consisting of Al, Ga, Zr, W, Fe, and Hf, R is an alkyl group having 1 to 12 carbon atoms, X is a halogen, wherein X is selected from F, Cl, or Br, m is in the range of 0 to 5, n is an integer in the range of 1 to 6, and wherein m+n is equal to the valency of M; wherein the catalyst system comprises one Lewis acid or a mixture of Lewis acids of Formula I.

3. The polymerization catalyst system as claimed in claim 2, wherein M is Al, Ga, or Fe, X is Cl or Br, R is an alkyl group having 1 to 8 carbon atoms, m ranges from 0 to 3, and n ranges from 1 to 4.

4. The polymerization catalyst system as claimed in claim 3, wherein M is Al, and the Lewis acid is selected from AlX.sub.3, alkyl AlX.sub.2, or a mixture of AlX.sub.3 and alkyl AlX.sub.2, wherein X is Cl or Br, and the alkyl group has 1 to 8 carbon atoms.

5. The polymerization catalyst system as claimed in claim 4, wherein X is Cl, and wherein the Lewis Acid is selected from AlCl.sub.3, or ethyl aluminum dichloride, or a mixture of AlCl.sub.3 and or ethyl aluminum dichloride.

6. The polymerization catalyst system as claimed in claim 1, wherein the Lewis base is selected from an ether, an alcohol, an amine, an ester, and mixtures thereof.

7. The polymerization catalyst system as claimed in claim 6, wherein the Lewis base is a dihydrocarbyl ether, wherein each hydrocarbyl group is independently selected from C.sub.1 to C.sub.8 hydrocarbyl.

8. The polymerization catalyst system as claimed in claim 7, wherein the hydrocarbyl group of the ether is selected from branched alkyl group, linear dialkyl group, sterically hindered alkyl group, or cyclic group.

9. The polymerization catalyst system as claimed in claim 7, wherein the Lewis base is selected from a sterically hindered ether, linear dialkyl ether, and a mixture of sterically hindered ether and linear dialkyl ether.

10. The polymerization catalyst system as claimed in claim 9, wherein the ether is selected from group consisting of methyl ether, ethyl ether, n-propyl ether, n-butyl ether, n-pentyl ether, n-hexyl ether, n-heptyl ether, n-octyl ether, sec-butyl ether, isopropyl ether, isobutyl ether, (2-ethylhexyl) ether, methyl n-butyl ether, methyl sec-butyl ether, methyl n-hexyl ether, methyl n-octyl ether, ethyl n-hexyl ether, ethyl n-octyl ether, ethyl 2-ethylhexyl ether, n-butyl n-octyl ether, n-butyl 2-ethylhexyl ether, ethyl n-butyl ether, ethyl sec-butyl ether, ethyl isobutyl ether, n-propyl-n-butyl ether, n-propyl sec-butyl ether, n-propyl isobutyl ether, n-propyl tert-butyl ether, isopropyl n-butyl ether, methyl isobutyl ether, methyl tert-butyl ether, isopropyl sec-butyl ether, isopropyl isobutyl ether, iso propyl tert-butyl ether, dicyclohexyl ether, diisopropyl ether, dibutyl ether, diphenyl ether, ditolyl ether, dibenzyl ether, tetrahydrofuran, tetrahydropyran, 1,2-dioxane, 1,3-dioxane and 1,4-dioxane.

11. The polymerization catalyst system as claimed in claim 1, wherein the catalyst system comprises sterically hindered ether, linear dialkyl ether and AlCl.sub.3, and wherein during polymerization reaction the catalyst is present in an amount ranging from 0.005 to 0.01 M.

12. The polymerization catalyst system as claimed in claim 11, wherein mole ratio of the sterically hindered ether, linear dialkyl ether, and AlCl.sub.3 is in the range of 0.25-0.75:0.25-0.75:0.5-1.

13. The polymerization catalyst system as claimed in claim 11, wherein the sterically hindered ether is diisopropyl ether and the linear dialkyl ether is dibutyl ether.

14. The polymerization catalyst system as claimed in claim 1, wherein the catalyst comprises a Lewis acid selected from AlCl.sub.3, ethyl aluminum dichloride (EADC), and a mixture of AlCl.sub.3 and ethyl aluminum dichloride; and a Lewis base mixture.

15. The polymerization catalyst system as claimed in claim 14, wherein the Lewis base mixture is a mixture of sterically hindered ether and linear dialkyl ether.

16. The polymerization catalyst system as claimed in claim 14, wherein molar ratio of AlCl.sub.3, ethylaluminum dichloride (EADC) and the Lewis base mixture is in the range of 0.25-0.75:0.25-0.75:0.5-1.5.

17. The polymerization catalyst system as claimed in claim 1, wherein the initiator is selected from hydrochloric acid, water, and a compound of the formula ROH or RX, wherein R is a hydrocarbyl group.

18. The polymerization catalyst system as claimed in claim 17, wherein the initiator is selected from tert-butyl chloride and adventitious moisture.

19. A process for preparing highly reactive polyisobutylene by liquid phase polymerization of isobutylene or an isobutylene containing feed stock using the polymerization catalyst system as claimed in claim 1, the process comprising: a) adding a non-polar solvent at a temperature ranging from −20° C. to 25° C. in a jacketed polymerization reactor equipped with a condenser operating at a temperature ranging from −20 to 10° C. under nitrogen atmosphere, wherein the non-polar solvent is selected from C.sub.4 feed, pentanes, hexanes, heptanes, octanes, decanes, paraffins, toluene, and xylenes, b) adding isobutylene or an isobutylene containing feed stock to the polymerization reactor containing the non-polar solvent, c) adding the polymerization catalyst system at a temperature ranging from −20° C. to 20° C. to the polymerization reactor, and d) terminating polymerization reaction after 1 hour by addition of a polymerization quencher and obtaining the highly reactive polyisobutylene, wherein the polymerization quencher is selected from alcohols, amines, caustics, and water, wherein polymer chains in the polyisobutylene comprises exo olefin end groups in an amount of greater than 70 mole % and molecular weight of the polyisobutylene rages from 500 to 5000 Dalton.

20. The process as claimed in claim 19, wherein the polymerization quencher is selected from methanol, water, sodium hydroxide solution, and ammonia solution.

Description

BRIEF DESCRIPTION OF THE DRAWING OF THE PRESENT INVENTION

[0028] FIG. 1 represents the 1H NMR spectrum of HRPIB prepared by the process of the present disclosure.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0029] Those skilled in the art will be aware that the present disclosure is subject to variations and modifications other than those specifically described. It is to be understood that the present disclosure includes all such variations and modifications. The disclosure also includes all such steps of the process, features of the product, referred to or indicated in this specification, individually or collectively, and any and all combinations of any or more of such steps or features. The present disclosure is not to be limited in scope by the specific embodiments described herein, which are intended for the purposes of exemplification only. Functionally-equivalent products and methods are clearly within the scope of the disclosure, as described herein.

[0030] The present invention provides a polymerization catalyst system for liquid phase polymerization of isobutylene or an isobutylene containing feed stock for producing highly reactive polyisobutylene, the catalyst system comprising: [0031] one or more Lewis acids, [0032] one or more Lewis bases, and [0033] optionally one or more initiators,

[0034] wherein the catalyst system is a complex of a Lewis acid with a mixture of Lewis bases, or a complex of a Lewis base with a mixture of Lewis acids;

[0035] wherein the polyisobutylene comprises homo or copolymers of isobutylene with at least 70 mole % of polymer chains in the polyisobutylene having exo olefin end groups. Thus, the present invention provides a catalyst of a catalyst-initiator system which comprises a Lewis acid.

[0036] In an embodiment, the Lewis acid is:

MR.sub.mX.sub.n  (Formula I)

[0037] wherein

[0038] M is selected from a group consisting of Al, Ga, Zr, W, Fe, and Hf,

[0039] R is an alkyl group having 1 to 12 carbon atoms,

[0040] X is a halogen, wherein X is selected from F, Cl, or Br,

[0041] m is in the range of 0 to 5,

[0042] n is an integer in the range of 1 to 6, and

[0043] wherein m+n is equal to the valency of M (e. g. 3 for Al);

[0044] wherein the catalyst system comprises one Lewis acid or a mixture of Lewis acids of Formula I.

[0045] In a further embodiment, M is Al, Ga, or Fe, X is Cl or Br, R is an alkyl group having 1 to 8 carbon atoms, m ranges from 0 to 3, and n ranges from 1 to 4. In a preferred embodiment, M is Al.

[0046] In another embodiment, the Lewis acid is selected from AlX.sub.3, alkyl AlX.sub.2, or a mixture of AlX.sub.3, alkyl AlX.sub.2 or a mixture of AlX.sub.3 and alkyl AlX.sub.2, wherein X is Cl or Br and the alkyl group has 1 to 8 carbon atoms. These compounds have been found to be particularly useful as Lewis acids for preparing complex with Lewis base.

[0047] In another embodiment, the present invention provides that X is Cl, wherein the Lewis Acid is selected from AlCl.sub.3 or ethyl aluminum dichloride, or a mixture of AlCl.sub.3 and or ethyl aluminum dichloride.

[0048] The Lewis base or nucleophile or complexing agent is any compound containing a lone pair of electrons. In one embodiment, the Lewis base is selected from an ether, an alcohol, an amine, an ester, and a mixture thereof.

[0049] In another embodiment, the Lewis base is selected from dihydrocarbyl ether, wherein each hydrocarbyl group is independently selected from C.sub.1 to C.sub.8 hydrocarbyl. In a preferred embodiment, the hydrocarbyl group of the ether is selected from branched alkyl group, linear dialkyl group, sterically hindered alkyl group, or cyclic group.

[0050] In an embodiment, the Lewis base is selected from a sterically hindered ether, linear dialkyl ether, and a mixture of sterically hindered ether and linear dialkyl ether.

[0051] In an embodiment, the ether is selected from group consisting of methyl ether, ethyl ether, n-propyl ether, n-butyl ether, n-pentyl ether, n-hexyl ether, n-heptyl ether, n-octyl ether, sec-butyl ether, isopropyl ether, isobutyl ether, (2-ethylhexyl) ether, methyl n-butyl ether, methyl sec-butyl ether, methyl n-hexyl ether, methyl n-octyl ether, ethyl n-hexyl ether, ethyl n-octyl ether, ethyl 2-ethylhexyl ether, n-butyl n-octyl ether, n-butyl 2-ethylhexyl ether, ethyl n-butyl ether, ethyl sec-butyl ether, ethyl isobutyl ether, n-propyl-n-butyl ether, n-propyl sec-butyl ether, n-propyl isobutyl ether, n-propyl tert-butyl ether, isopropyl n-butyl ether, methyl isobutyl ether, methyl tert-butyl ether, isopropyl sec-butyl ether, isopropyl isobutyl ether, iso propyl tert-butyl ether, dicyclohexyl ether, diisopropyl ether, dibutyl ether, diphenyl ether, ditolyl ether, dibenzyl ether, tetrahydrofuran, tetrahydropyran, 1,2-dioxane, 1,3-dioxane and 1,4-dioxane. Among the above-mentioned ethers, sterically hindered ether, linear dialkyl ether or a mixture of sterically hindered and linear dialkyl ethers have been found to be particularly useful as Lewis bases for preparing complex with Lewis acid.

[0052] The hydrocarbyl groups (one or both) of the branched ether, linear dialkyl ether, sterically hindered ether, and cyclic ether are optionally substituted with an electron-donating group or electron-withdrawing group. The catalyst of the present invention is AlCl.sub.3, EADC or a mixture thereof together with nucleophiles, sometimes referred to as Lewis bases or complexing agents.

[0053] In one embodiment, the catalyst system comprises sterically hindered ether, linear dialkyl ether, and AlCl.sub.3, wherein during polymerization reaction the catalyst is present in an amount ranging from 0.005-0.01 M. In yet another embodiment, the mole ratio of the sterically hindered ether, linear dialkyl ether, and AlCl.sub.3 is in the range of 0.25-0.75:0.25-0.75:1.

[0054] In a preferred embodiment, the sterically hindered ether is diisopropyl ether and the linear dialkyl ether is dibutyl ether.

[0055] In another embodiment, the catalyst comprises: [0056] a Lewis acid selected from AlCl.sub.3, or ethyl aluminum dichloride (EADC), or and a mixture of AlCl.sub.3 and ethyl aluminum dichloride; and [0057] a Lewis base mixture.

[0058] In a preferred embodiment, the Lewis base mixture is a mixture of sterically hindered ether and linear dialkyl ether.

[0059] In another embodiment, the molar ratio of AlCl.sub.3 or ethylaluminum dichloride (EADC) or a mixture of AlCl.sub.3 and ethyl aluminum dichloride to complexing agent or Lewis bases mixture or nucleophiles mixture or ethers mixture in the catalyst composition is generally in the range of 1:0.5 to 1:4, preferably from about 1:0.75 to about 1:1.5, more preferably from about 1:1 to about 1:1.1. In a preferred embodiment, the molar ratio is 1:1.

[0060] In a preferred embodiment, molar ratio of AlCl.sub.3, ethylaluminum dichloride (EADC) and the Lewis base mixture is in the range of 0.25-0.75:0.25-0.75:0.5-1.5

[0061] Typically, the Lewis acid catalyst together with nucleophile or Lewis base or complexing agent is dosed in a single dose or continuously or in a pulsed manner in the polymerization reactor. The catalyst system employed is typically passed into the polymerization reactor in the form of a slurry or completely dissolved in a solvent, or as a solid.

[0062] The invention is directed to a chain transfer cationic polymerization of IB or a C4 feed containing IB and other C4 olefins in a non-polar medium at a temperature in the range of −20° C. to +20° C., initiated using Lewis acid complexes comprising certain mixtures of nucleophiles. This polymerization of IB provides high yields of HR PIB and high IB conversion.

[0063] In another embodiment, the initiator of the present invention is selected from hydrochloric acid, water, and a compound of the formula ROH or RX, wherein R is a hydrocarbyl group capable of forming a stable carbonation, for example, benzylic or tertiary carbonation. In one preferred embodiment of the invention, the initiator is tert-butyl chloride. In another preferred embodiment of the invention, the initiator is adventitious moisture. In the present invention, the moisture works as initiator and there is no need to add any initiator separately. Because of this advantage, the moisture pre-existing in the polymerization reaction is the adventitious moisture. Undried reaction solvent like hexane, catalyst components like ethers and monomer feed like isobutylene/C4 obviously consist of certain ppm level of moisture. Apparently, required active cationic species for the polymerization are generated only from the moisture in the presence of AlCl.sub.3.ether complex. On the contrary, if the cationic polymerization is conducted in dry conditions, there could be requirement of some external active species generators/initiators namely, alcohols, alkyl halides, esters, etc.

[0064] Further, the present invention provides a process for preparing highly reactive polyisobutylene by liquid phase polymerization of isobutylene or an isobutylene containing feed stock using the disclosed polymerization catalyst system, the process comprising: [0065] a) adding a non-polar solvent at a temperature ranging from −20 to 25° C. in a jacketed polymerization reactor equipped with a condenser operating at a temperature ranging from −20 to 10° C. under nitrogen atmosphere, [0066] b) adding isobutylene or an isobutylene containing feed stock to the polymerization reactor containing the non-polar solvent, [0067] c) adding the polymerization catalyst system at a temperature ranging from −20° C. to 20° C. to the polymerization reactor, and [0068] d) terminating polymerization reaction after 1 hour by addition of a polymerization quencher and obtaining the highly reactive polyisobutylene,

[0069] wherein polymer chains in the polyisobutylene comprises exo olefin end groups in an amount of is greater than 70 mole % and molecular weight of the polyisobutylene ranges from 250 to 10000 Dalton, preferably 500 to 5000 Dalton.

[0070] In yet another embodiment, the non-polar solvent is selected from C4 feed, pentanes, hexanes, heptanes, octanes, decanes, paraffins, toluene, or xylenes.

[0071] After the desired parameters of the HRPIB are attained in the polymerization of IB or IB containing feed stock, the polymer product is quenched with a medium that quenches the polymerization catalyst and stops the polymerization. In an embodiment, the polymerization quencher is selected from alcohols, amines, caustics, and water. By washing with caustic, traces of the residual quantities of catalyst are removed. In a preferred embodiment, the polymerization quencher is selected from methanol, water, sodium hydroxide solution, ammonia solution, etc.

[0072] The IB or IB containing feed stock polymerization in a continuous process under steady state conditions is of industrial interest. The conventional continuous process reactors, such as continuous stirred tank reactors, tube reactors, or tube-bundle reactors, are used for feed stock polymerization. Obviously, the inlet feed rate is equal to the rate of the polymerization discharge/outlet after the steady-state equilibrium has been established in the polymerization reactor.

Abbreviations

[0073] IB=Isobutylene

[0074] HRPIB=Highly reactive polyisobutylene

[0075] AlCl.sub.3=Aluminum trichloride

[0076] EADC=Ethylaluminum dichloride

[0077] i-Pr.sub.2O=Diisopropyl ether

[0078] Bu.sub.2O=Dibutyl ether

[0079] NMR=Nuclear magnetic resonance

[0080] Technical advantages of the present invention: [0081] 1. Present invention overcomes challenges of cost and corrosive byproducts formation associated with traditional commercial catalyst. [0082] 2. Present invention provides efficient, highly active, and low cost AlCl.sub.3 based catalyst system for HRPIB preparation in completely non-polar solvent medium. [0083] 3. Combination of different catalyst components such as Lewis acids mixture or Lewis bases mixture is able solve the prior art disadvantages, including conversion, exo content, catalyst performance or activity in nonpolar solvents, etc. [0084] 4. The catalyst system of the present invention works at 0-10° C., whereas a traditional commercial catalyst requires temperatures as low as −30° C. [0085] 5. The invention enables high conversions and production of polyisobutylene having high exo olefin content of greater than 75%. [0086] 6. Polyisobutylene with targeted molecular weight of 250-10000 Dalton, particularly 500-5000 Dalton are achieved by controlling polymerization parameters. [0087] 7. The process is environmentally friendly with no usage of dangerous chemicals like chlorinated solvents/chlorinated ethers.

EXAMPLES

[0088] The disclosure will now be illustrated with working examples, which is intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice of the disclosed methods, the exemplary methods, devices and materials are described herein. It is to be understood that this disclosure is not limited to particular methods, and experimental conditions described, as such methods and conditions may vary.

Example 1

[0089] Polymerizations were performed in a jacketed reactor equipped with condenser operating at −10° C. under nitrogen atmosphere. In a typical example of experiment, 800 mL of hexanes was placed in the reactor at 0° C. 200 mL of IB (4 M) was condensed and added to the polymerization reactor containing hexanes. Then, polymerization was started under stirring by the addition of the prepared AlCl.sub.3⋅ethers complex, 0.01 M (wherein, [AlCl.sub.3]=0.01 M, [i-Pr.sub.2O]=0.005 M, and [Bu.sub.2O]=0.005 M) to the reactors at 0° C. After 1 hour of the polymerization time, polymerization was terminated by addition of methanol. 98% polymerization yield observed. The product had Mn, NMR=1500 Dalton, and exo olefin content 78%.

[0090] The polymerization yields were determined gravimetrically. The distribution of different olefin end-groups and molecular weight (Mn, NMR) were determined by 1H NMR.

Example 2

[0091] Polymerizations were performed in a jacketed reactor equipped with condenser operating at −10° C. under nitrogen atmosphere. In a typical example of experiment, 800 mL of hexanes was placed in the reactor at 0° C. 200 mL of IB (4 M) was condensed and added to the polymerization reactor containing hexanes. Then, polymerization was started under stirring by the addition of the prepared Lewis acids⋅i-Pr.sub.2O complex, 0.01 M (wherein, [AlCl.sub.3]=0.005 M, [EADC]=0.005 M, and [i-Pr.sub.2O]=0.01 M) to the reactors at 0° C. After 1 hour of the polymerization time, polymerization was terminated by addition of NaOH solution. 98% polymerization yield observed. The product had Mn, NMR=1500 Dalton, and exo olefin content 80%.

TABLE-US-00001 TABLE 1 Polymerization of IB using [Lewis acid .Math. Lewis base] = 0.005 to 0.01 M in dry hexanes at 0° C. with [Lewis acid]/[Lewis base] = 0.5 to 1.0 Mn, [AlCl.sub.3] [i-Pr.sub.2O] [Bu.sub.2O] Conv..sup.a NMR.sup.b exo.sup.b Entry (M) (M) (M) (%) (Dalton) (%) 1. 0.01 0.01 — 98 1300 56 2. 0.01 — 0.01 28 2800 77 3. 0.01 0.005 0.005 98 1500 78 4. 0.01 0.0025 0.0075 97 1500 66 5. 0.01 0.0075 0.0025 62 2100 79 6..sup.c 0.01 0.005 0.005 87 1700 76 7. 0.01 0.001 0.009 30 2800 76 8. 0.01 0.009 0.001 98 1400 58 9. 0.01 0.006 0.006 98 1000 84 10. 0.01 0.0075 0.0075 72  800 85 11. 0.01 0.01 0.01 14 3200 85 12. 0.005 0.0025 0.0025 74 2600 77 13..sup.d 0.01 0.005 0.005 98 1400 77 14..sup.c 0.01 0.005 0.005 95 1500 79 .sup.aDetermined gravimetrically (Macromolecules 2012, 45, 8598-8603) based on [IB] .sup.bDetermined by 1H NMR .sup.cC4 feed was used for the polymerization .sup.dAromatic solvent, toluene was used for the polymerization .sup.cCyclic ether, tetrahydrofuran was used instead of Bu.sub.2O for the polymerization

[0092] The polymerization of IB in the presence of mixture of ethers (i-Pr.sub.2O and Bu.sub.2O, at particular ratio with respect to AlCl.sub.3) afforded HR PIB with synergistic effect resulting in a high yield (98%) and with high exo content (85%) in comparison with these obtained with neat i-Pr.sub.2O or Bu.sub.2O (compare Entry 1 and 2 with Entry 3-13).

TABLE-US-00002 TABLE 2 Polymerization of IB using [Lewis acid .Math. Lewis base] = 0.005 to 0.02 M in dry hexanes at 0° C. with [Lewis acid]/[Lewis base] = 0.5 to 1.0 Mn, [AlCl.sub.3] [EADC] [i-Pr.sub.2O] [Bu.sub.2O] Conv..sup.a NMR.sup.b exo.sup.b Entry (M) (M) (M) (M) (%) (Dalton) (%) 1. 0.01 — 0.01 — 98 1300 56 2. — 0.01 0.01 — 07 4200 82 3. 0.005 0.005 0.01 — 98 1400 84 4. 0.0025 0.0075 0.01 — 85 1800 80 5. 0.0075 0.0025 0.01 — 98 1400 64 6..sup.c 0.005 0.005 0.01 — 86 1600 76 7. 0.001 0.009 0.01 — 10 3800 83 8. 0.009 0.001 0.01 — 98 1300 55 9. 0.01 0.01 0.02 — 98 1000 81 10. 0.0025 0.0025 0.005 — 70 2800 80 11. 0.01 — — 0.01 28 2800 77 12. — 0.01 — 0.01 <5 4200 88 13. 0.005 0.005 — 0.01 20 3400 82 14..sup.d 0.005 0.005 0.01 — 98 1300 83 .sup.aDetermined gravimetrically (Macromolecules 2012, 45, 8598-8603) based on [IB] .sup.bDetermined by 1H NMR .sup.cCatalyst was blended with low molecular weight HR PIB .sup.dAromatic solvent, xylene was used for the polymerization

[0093] The polymerization of IB in the presence of mixture of Lewis acids (AlCl.sub.3 and EADC, at particular ratio with respect to i-Pr.sub.2O) afforded HR PIB with synergistic effect resulting in high yield (98%) and with high exo content (84%) in comparison with these obtained with neat AlCl.sub.3 or EADC (compare Entry 1 and 2 with Entry 3-10).

TABLE-US-00003 TABLE 3 Polymerization of IB using [Lewis acid .Math. Lewis base] = 0.01 M in dry hexanes at 0° C. with [Lewis acid]/[Lewis base] = 1.0 and used different polymerization quenchers Mn, [AlCl.sub.3] [EADC] [iPr.sub.2O] Conv..sup.a NMR.sup.b exo.sup.b Entry (M) (M) (M) Quencher (%) (Dalton) (%) 1. 0.005 0.005 0.01 Methanol 98 1300 83 2. 0.005 0.005 0.01 Water 98 1400 82 3. 0.005 0.005 0.01 Sodium 98 1400 83 hydroxide solution 4. 0.005 0.005 0.01 Ammonia 98 1300 82 solution .sup.aDetermined gravimetrically (Macromolecules 2012, 45, 8598-8603) based on [IB] .sup.bDetermined by 1H NMR

[0094] The distribution of PIB end-groups was determined by 1H NMR spectroscopy (Macromolecules 2012, 45, 8598-8603). The olefinic region of the spectrum shown in FIG. 1 refers to two major characteristic signals at 4.64 and 4.85 ppm of the exo-olefin end groups. The small peaks of endo, tri (both the E and Z configurations), and tetra-substituted olefinic end groups are observed at 5.15, 5.37 and 5.17, and 2.84 ppm, respectively. Moreover, the methylene and methyl protons of the PIB main chain repeat units are observed at 1.42 and 1.11 ppm, respectively.