SILYL BIS(HEXAMETHYLINDENYL) COMPLEXES OF GROUP IVA METALS AS POLYMERIZATION CATALYSTS

Abstract

Novel Si-bridged metallocene catalysts of formula I defined herein are disclosed, as well as their use in olefin polymerisation reactions.

##STR00001##

Claims

1. A compound of the formula I shown below: ##STR00026## wherein: R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each (1-3C)alkyl; R.sub.a and R.sub.b are independently selected from the group consisting of (1-6C)alkyl, (1-6C)alkoxy, (2-6C)alkenyl, (2-6C)alkynyl, (1-6C)alkylamino, [(1-6C)alkyl].sub.2amino, aryl, halo, amino, nitro and cyano; X is selected from the group consisting of zirconium, titanium and hafnium; and each Y group is independently selected from the group consisting of halo, hydride, phosphonate, sulfonate, borate, (1-6C)alkyl, (1-6C)alkoxy, aryl, aryl(1-3C)alkyl and aryloxy group, wherein each of (1-6C)alkyl, (1-6C)alkoxy, aryl, aryl(1-3C)alkyl and aryloxy group is optionally substituted with halo, nitro, amino, phenyl, (1-6C)alkoxy, or Si[(1-4C)alkyl].sub.3, or, both Y groups are (1-3C)alkylene groups joined at their respective ends to a group Q, such that when taken with X and Q, the two Y groups form a 4, 5 or 6-membered ring; wherein Q is Si(R.sub.x)(R.sub.y), wherein R.sub.x and R.sub.y are independently (1-4C)alkyl.

2. The compound according to claim 1, wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each independently (1-2C)alkyl.

3. The compound according to claim 1, wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are all methyl.

4. The compound according to claim 1, wherein X is zirconium or hafnium.

5. The compound according to claim 1, wherein R.sub.a and R.sub.b are each independently (1-6C)alkyl or (2-6C)alkenyl.

6. The compound according to claim 1, wherein R.sub.a and R.sub.b are each independently (1-4C)alkyl.

7. The compound according to claim 1, wherein each Y is independently halo or (1-2C)alkyl group which is optionally substituted with halo, phenyl, or Si[(1-4C)alkyl].sub.3.

8. The compound according to claim 1, wherein Y is halo.

9. The compound according to claim 8, wherein R.sub.a and R.sub.b are each independently selected from the group consisting of methyl, propyl and allyl.

10. The compound according to claim 9, wherein X is zirconium.

11. The compound according to claim 1, where the compound has the structural formula: ##STR00027##

12. The compound according to claim 1, where the compound has the structural formula: ##STR00028##

13-14. (canceled)

15. A composition comprising a compound of formula I as defined in claim 1, and a suitable activator.

16. The composition of claim 15, wherein the suitable activator is solid MAO and the compound of formula I is supported thereon.

17. A process for forming a polyethylene which comprises reacting olefin monomers in the presence of (i) a compound of formula I as defined in claim 1, and (ii) a suitable activator.

18. The process according to claim 17, wherein the activator comprises an aluminoxane, tri(isobutyl)aluminium (TIBA) or triethylaluminium (TEA).

19. The process according to claim 17, wherein the activator is provided as an activated support.

20. The process according to claim 19, wherein the compound of formula I is supported on the activated support.

21. The process according to claim 19, wherein the activated support is methylaluminoxane activated silica or methylaluminoxane activated AMO-MgAl layered double hydroxide.

22. The process according to claim 19, wherein the activated support is solid methylaluminoxane.

Description

EXAMPLES

[0118] Examples of the invention will now be described by reference to the accompanying figures, in which:

[0119] FIG. 1 shows the molecular structure of rac-[(SBI*)ZrCl.sub.2] determined by X-ray crystallography.

[0120] FIG. 2 shows the .sup.1H NMR spectroscopy of rac-[(SBI*)ZrCl.sub.2] (CDCl.sub.3, 23 C., 400 MHz).

[0121] FIG. 3 shows the .sup.1H NMR (400 MHz) spectrum of (SBI*)Zr(CH.sub.2Ph).sub.2 in benzene-d.sub.6. Asterisk marks the residual protio-solvent resonance which is coincident with a multiplet in the aromatic region.

[0122] FIG. 4 shows the molecular structure of rac-(SBI*)Zr(CH.sub.2)CH.sub.2SiMe.sub.2, 50% ellipsoids, hydrogen atoms omitted for clarity; grey: carbon, pink: zirconium and green: chloride.

[0123] FIG. 5 shows the .sup.1H NMR (400 MHz) spectrum of (SBI*.sup.3-Ethyl)ZrCl.sub.2 in benzene-d.sub.6.

[0124] FIG. 6 shows the molecular structure of (SBI*.sup.3-Ethyl)ZrCl.sub.2 rac- (left) and meso- (right), 50% ellipsoids, hydrogen atoms omitted for clarity; grey: carbon, orange: silicon, pink: zirconium and green: chloride.

[0125] FIG. 7 shows the .sup.1H NMR (400 MHz) spectrum of (SBI*.sup.3-Ethyl)Zr(CH.sub.2Ph).sub.2 in benzene-d.sub.6.

[0126] FIG. 8 shows the molecular structure of rac-(SBI*.sup.3-Ethyl)Zr(CH.sub.2Ph).sub.2, 50% ellipsoids, hydrogen atoms omitted for clarity; grey: carbon, orange: silicon, and pink: zirconium.

[0127] FIG. 9 shows scanning electron microscopy images at 500 and 5000 magnification. a) AMO-MgAlSO.sub.4 LDH; b) AMO-MgAlSO.sub.4 LDHMAO; c) AMO-MgAlSO.sub.4 LDHMAO-(SBI*)ZrCl.sub.2.

[0128] FIG. 10 shows scanning electron microscopy images at 500 magnification. a) amorphous SiO.sub.2 (Grace); b) SSMAO; c) SSMAO-(SBI*)ZrCl.sub.2.

[0129] FIG. 11 shows a graph demonstrating the ethylene polymerisation activity dependence of rac-(SBI*)ZrCl.sub.2 on temperature. MAO (2000:1); 2 bar ethylene; 0.2 mg catalyst loading; 50 ml hexane; timed until cessation of stirring.

[0130] FIG. 12 shows a graph demonstrating the dependence of activity and molecular weight, M.sub.w, for rac-(SBI*)ZrCl.sub.2 on the Al:Zr co-catalyst (MAO) ratio. PDIs are given in parentheses. 70 C.; 2 bar ethylene; 0.2 mg catalyst loading; 50 ml hexane; timed until cessation of stirring.

[0131] FIG. 13 shows a graph demonstrating the ethylene polymerisation activity dependence of rac-(SBI*)ZrCl.sub.2 on temperature, supported on SSMAO (200:1 loading) and LDHMAO (300:1 loading). TIBA co-catalyst; 2 bar ethylene; 10 mg catalyst; 50 ml hexane; 30 minutes.

[0132] FIG. 14 shows a graph demonstrating the dependence of activity and M.sub.w for rac-(SBI*)ZrCl.sub.2 on temperature. PDIs are given in parentheses. Supported on SSMAO (200:1 loading); TIBA co-catalyst; 2 bar ethylene; 10 mg catalyst; 50 ml hexane; 30 minutes.

[0133] FIG. 15 shows a graph demonstrating the dependence of activity and M.sub.w for rac-(SBI*)ZrCl.sub.2 on length of run. PDIs are given in parentheses. Supported on SSMAO (200:1 loading); TIBA co-catalyst; 70 C.; 2 bar ethylene; 10 mg catalyst; 50 ml hexane.

[0134] FIG. 16 shows a graph demonstrating the dependence of activity and M.sub.w, for rac-(SBI*)ZrCl.sub.2 on temperature. PDIs are given in parentheses. Supported on Solid MAO (300:1 loading); TIBA co-catalyst; 2 bar ethylene; 10 mg catalyst; 50 ml hexane; 30 minutes.

[0135] FIG. 17 shows a graph demonstrating the ethylene polymerisation activity dependence of rac-EBI*ZrCl.sub.2 and rac-(SBI*)ZrCl.sub.2 on temperature. Supported on Solid MAO (200:1 rac-EBI*ZrCl.sub.2, 300:1 rac-SBI*ZrCl.sub.2); TIBA co-catalyst; 2 bar ethylene; 10 mg catalyst; 50 ml hexane; 30 minutes.

[0136] FIG. 18 shows a graph demonstrating the variation in molecular weight, M.sub.w, of the polyethylene produced by rac-(SBI*)ZrCl.sub.2 in solution and on three different supports. PDIs are given in parentheses. 70 C.; 2 bar ethylene; 0.2 mg catalyst (solution), 10 mg catalyst (slurry); 50 ml hexane; timed until cessation of stirring or 30 minutes, where possible.

[0137] FIG. 19 shows a graph demonstrating the ethylene polymerisation activity dependence of rac-(SBI*.sup.3-ethyl)ZrCl.sub.2 on temperature. Supported on Solid MAO (200:1); TIBA co-catalyst; 2 bar ethylene; 10 mg catalyst; 50 ml hexane; 30 minutes.

[0138] FIG. 20 shows a graph demonstrating the ethylene polymerisation activity dependence of rac-(SBI*.sup.3-ethyl)ZrCl.sub.2 on time. Supported on Solid MAO (200:1); TIBA co-catalyst; 2 bar ethylene; 10 mg catalyst; 50 ml hexane; 30 minutes.

[0139] FIG. 21 shows a graph demonstrating the ethylene polymerisation activity dependence of rac-(SBI*.sup.3-ethyl)ZrCl.sub.2 on temperature in solution. MAO co-catalyst; 2 bar ethylene; 0.5 mg complex; 50 ml hexane; 2 minutes.

[0140] FIG. 22 shows a graph demonstrating the ethylene-1-hexene copolymerisation activity dependence of Solid MAO/rac-(SBI*)ZrCl.sub.2 on time. TEA co-catalyst; 8 bar ethylene; 0.10 mg catalyst; 5 ml heptane; 70 C.

INTERMEDIATE 1

Synthesis of Si-Bridged Alkyl Indenyl Ligands ((SBI) Ligands)

[0141] The synthesis of silane proligands was achieved by reacting two equivalents of indenyl lithium, [(Ind.sup.#)Li], with one equivalent dichlorosilane at room temperature in tetrahydrofuran. After work-up, [(SBI*)H.sub.2], [(.sup.Me,PropylSBI*)H.sub.2] and [(.sup.Me,AllylSBI*)H.sub.2], shown below, were obtained as colourless powders in high yield.

##STR00016##

Example 1

Synthesis of Si-Bridged Alkyl Indenyl Zirconocene Complexes

Synthesis of [(SBI*)ZrCl.SUB.2.]

[0142] The synthesis of [(SBI*)ZrCl.sub.2] was achieved by reacting [(SBI*)H.sub.2] with two equivalents of n-butyllithium at room temperature. After work-up, [(SBI*)Li.sub.2] was obtained as a yellow powder in quantitative yield.

[0143] In a Schlenk tube, 1.06 mmol stoichiometric reaction of 0.5 g of [(SBI*)Li.sub.2] and 0.25 g of ZrCl.sub.4 in benzene (50 mL) was stirred at room temperature for 2 hours. Then the red solution was filtered away from the colourless solid, LiCl, by-product, concentrated in vacuum to half and leaved standing over-night at room temperature. Orange crystals were formed, the solution was filtered away and the crystals were dried to afford rac-[(SBI*)ZrCl.sub.2], shown below, as an orange solid in crystalline material yield.

##STR00017##

Synthesis of [(.SUP.Me, Propyl.SBI*)ZrCl.SUB.2.] and [(.SUP.Me, Allyl.SBI)ZrzCl.SUB.2.]

[0144] Using the Si-bridged alkyl indenyl ligand intermediates described above, [(.sup.Me, PropylSBI*)ZrCl.sub.2] and [(.sup.Me, AllylSBI*)ZrCl.sub.2], shown below, were prepared according to the method described in relation to [(SBI*)ZrCl.sub.2] above.

##STR00018##

Synthesis of dimethylsiliconbis[1(2,3,4,5,6,7-hexamethylindenyl)]zirconium dibenzyl, [(SBI*)Zr(CH.SUB.2.Ph).SUB.2.]

[0145] Using the Si-bridged alkyl indenyl ligand intermediates described above, [(SBI*)Zr(CH.sub.2Ph).sub.2], shown below, was prepared according to the method described in relation to [(SBI*)ZrCl.sub.2] above.

##STR00019##

Synthesis of dimethylsiliconbis[1(2,3,4,5,6,7-hexamethylindenyl)]zirconium alkyl, [(SBI*)Zr(CH.SUB.2.)CH.SUB.2.SiMe.SUB.2.]

[0146] Using the Si-bridged alkyl indenyl ligand intermediates described above, [(SBI*)Zr(CH.sub.2)CH.sub.2SiMe.sub.2], shown below, was prepared according to the method described in relation to [(SBI*)ZrCl.sub.2] above.

##STR00020##

Synthesis of dimethylsiliconbis[1-(2-ethyl-3,4,5,6,7-pentamethylindenyl)]zirconium dichloride, [(SBI*.SUP.3-Ethyl.)ZrCl.SUB.2.]

[0147] Using the Si-bridged alkyl indenyl ligand intermediates described above, [(SBI*.sup.3-Ethyl)ZrCl.sub.2], shown below, was prepared according to the method described in relation to [(SBI*)ZrCl.sub.2] above.

##STR00021##

Synthesis of dimethylsiliconbis[1-(2-ethyl-3,4,5,6,7-pentamethylindenyl)]zirconium dibenzyl, [(SBI*.SUP.3-Ethy.l)Zr(CH.SUB.2.Ph).SUB.2.]

[0148] Using the Si-bridged alkyl indenyl ligand intermediates described above, [(SBI*.sup.3-Ethtyl)Zr(CH.sub.2Ph).sub.2], shown below, was prepared according to the method described in relation to [(SBI*)ZrCl.sub.2] above.

##STR00022##

Example 2

Characterisation of Si-Bridged Alkyl Indenyl Zirconocene Complexes

Characterisation of [(SBI*)ZrCl.SUB.2.]

[0149] Single crystals suitable for X-ray crystallography were grown from room temperature benzene solution. The molecular structure of rac-[(SBI*)ZrCl.sub.2] is shown in FIG. 1, in which ellipsoids are drawn at 50% probability level. Hydrogen atoms were omitted for clarity. The bond lengths and angles of [(SBI*)ZrCl.sub.2] are within the range of the literature.

[0150] The .sup.1H NMR spectroscopy of rac-[(SBI*)ZrCl.sub.2] is shown FIG. 2. It shows 5 resonances for 36 methyl groups for the ligand around 1.71-2.42 ppm and one resonance for the dimethylsilyl group at 1.28 ppm.

Characterisation of [(SBI*)Zr(CH.sub.2Ph).sub.2]

[0151] FIG. 3 shows .sup.1H NMR (400 MHz) spectrum of (SBI*)Zr(CH.sub.2Ph).sub.2 in benzene-d.sub.6. Asterisk marks the residual protio-solvent resonance which is coincident with a multiplet in the aromatic region.

[0152] .sup.1H NMR (400 MHz, C.sub.6D.sub.6): 1.10 (s, 6H, Si-Me), 1.69 (s, 6H, Ar-Me), 1.79 (s, 6H, Ar-Me), 2.11 (s, 12H, Ar-Me), 2.13 (s, 4H, Ph-CH.sub.2), 2.37 (s, 6H, Ar-Me), 2.40 (s, 6H, Ar-Me), 6.75 (d, J=7.1 Hz, 4H, o-Ph), 6.85 (t, J=6.5 Hz, 2H, p-Ph), 7.13 (t, J=7.0 Hz, 4H, m-Ph).

[0153] .sup.13C{.sup.1H} NMR (400 MHz, C.sub.6D.sub.6): 11.31 (Si-Me), 14.20 (Ar-Me), 15.25 (Ar-Me), 16.41 (Ar-Me), 17.43 (Ar-Me), 17.89 (Ar-Me), 22.00 (Ar-Me), 70.49 (PhCH.sub.2), 121.48 (o-Ph), 124.30 (Ar), 125.70 (Ar), 126.81 (p-Ph), 127.94 (Ar), 128.18 (Ar), 128.41 (Ar), 128.57 (m-Ph), 129.33 (Ar), 129.64 (Ar), 131.21 (Ar), 133.72 (Ar), 134.00 (Ar).

[0154] IR (KBr) (cm.sup.1): 2962, 1544, 1434, 1261, 1093, 1022, 802, 668.

Characterisation of [(SBI*)Zr(CH.sub.2)CH.sub.2SiMe.sub.2]

[0155] The molecular structure for [(SBI*)Zr(CH.sub.2)CH.sub.2SiMe.sub.2] is shown in FIG. 4, in which ellipsoids are drawn at 50% probability level. Hydrogen atoms were omitted for clarity.

Characterisation of [(SBI*.sup.3-Ethyl)ZrCl.sub.2]

[0156] FIG. 5 shows .sup.1H NMR (400 MHz) spectrum of [(SBI*.sup.3-Ethyl)ZrCl.sub.2] in benzene-d.sub.6.

[0157] The molecular structure for [(SBI*.sup.3-Ethyl)ZrCl.sub.2] is shown in FIG. 6 (rac: left; meso: right), in which ellipsoids are drawn at 50% probability level. Hydrogen atoms were omitted for clarity.

Characterisation of [(SBI*.sup.3-Ethyl)Zr(CH.sub.2Ph).sub.2]

[0158] FIG. 7 shows .sup.1H NMR (400 MHz) spectrum of [(SBI*.sup.3-Ethyl)Zr(CH.sub.2Ph).sub.2] in benzene-d.sub.6.

[0159] The molecular structure for [(SBI*.sup.3-Ethyl)Zr(CH.sub.2Ph).sub.2] is shown in FIG. 8, in which ellipsoids are drawn at 50% probability level. Hydrogen atoms were omitted for clarity.

Example 3

Synthesis of Activated Solid-Supports (Eg. SSMAO or LDHMAO)

[0160] In slurry polymerisation of olefins the molecular pro-catalysts may be immobilized on an activated support which is insoluble under polymerisation conditions. Suitable solid supports include; methylaluminoxane activated silica (SiO.sub.2), solid methylaluminoxane and methylaluminoxane activated AMO-MgAl layered double hydroxide (LDHMAO) (eg. of an AMO-MgAl is [Mg.sub.1-xAl.sub.x(OH)].sup.x+(A.sup.n).sub.a/n 0.55(H.sub.2O)0.13 (acetone). (0.1<x>0.9; A=anion eg. CO.sub.3.sup.2, SO.sub.4.sup.2).

[0161] To a Schlenk tube containing a slurry of two equivalents of an amorphous spherical silica or [Mg.sub.0.75Al.sub.0.25(OH).sub.2](SO.sub.4).sub.0.1250.55(H.sub.2O)0.13(acetone) in toluene (25 ml), a colourless solution of one equivalent of methylaluminoxane in toluene (25 ml) was added swiftly at room temperature. The mixture was heated to 80 C. and left for two hours with occasional swirling. The resulting suspension was then left to cool down to room temperature and the toluene solvent was carefully filtered and removed in vacuo to obtain methylaluminoxane activated silica (SSMAO) or methylaluminoxane activated AMO-MgAl layered double hydroxide (LDHMAO) as a white, free-flowing powders in quantitative yield (3.14 g).

Example 4

Synthesis of Solid-Supported [(SBI*)ZrCl.SUB.2.] Catalysts

[0162] To a Schlenk tube containing a slurry of SSMAO, LDHMAO or Solid MAO (1.00 g) in toluene (25 ml), a solution of an appropriate amount of an orange solution of [(SBI*)ZrCl.sub.2] in toluene (25 ml) was added swiftly at room temperature. The mixture was heated to 60 C. and left, with occasional swirling, for two hours during which time the solution turned colourless and the solid colourised purple. The resulting suspension was then left to cool down to room temperature and the toluene solvent was carefully filtered and removed in vacuo to obtain solid-supported [(SBI*)ZrCl.sub.2] catalyst as a light purple, free-flowing powder.

[0163] FIG. 9 shows scanning electron microscopy images at 500 and 5000 magnification. a) AMO-MgAlSO.sub.4 LDH; b) AMO-MgAlSO.sub.4 LDHMAO; c) AMO-MgAlSO.sub.4 LDHMAO-(SBI*)ZrCl.sub.2. FIG. 9 clearly reveals two points; small particle size of AMO-LDHs and the consistency of their morphology under the immobilisation process. Image a) illustrates the small diameters of the individual particles, which are poorly resolved even under 5000 magnification, and a high surface area was anticipated. It is also noteworthy that there is a significant degree of aggregation of the smaller particles. Images b) and c) display the fine detail which appears unaffected by the reaction with MAO or the complex -(SBI*)ZrCl.sub.2 as well as the aggregation noted above.

LDHMAO-(SBI*)ZrCl.SUB.2.:

[0164] .sup.13C CPMAS NMR: 9.32 (AlOMe), 12.87 (SiMe.sub.2), 22.44 (Ar-Me), 24.57 (Ar-Me), 29.54 (Ar-Me), 31.10 (Ar-Me), 74.97 (Cp), 128.39 (Ar).

[0165] .sup.27Al CPMAS NMR: 527, 28, 470.

LDHMAO-(SBI*)ZrCl.SUB.2.:

[0166] .sub.max=395 nm.

[0167] FIG. 10 shows scanning electron microscopy images at 500 magnification. a) amorphous SiO.sub.2 (Grace); b) SSMAO; c) SSMAO-(SBI*)ZrCl.sub.2. FIG. 10 illustrates a dramatically different particle morphology from LDH. The silica, supplied by Grace, is much more uniform in shape and size with no aggregation. The particles are not spherical but granular with an average size of approximately 10 m. They do not change in either shape or dimension on reaction with MAO, nor on the immobilisation of (SBI*)ZrCl.sub.2. It can be seen that no further aggregation has occurred, justifying the omission of stirrer bars during the supporting procedure.

SSMAO-(SBI*)ZrCl.SUB.2.:

[0168] .sup.13C CPMAS NMR: 9.03 (AlOMe).

[0169] .sup.27Al CPMAS NMR: 309, 113, 3, 182, 336.

[0170] .sup.29Si CP SSMAO-EBI*ZrCl.sub.2: .sub.max=390 nm.

SSMAO-(SBI*)ZrCl.SUB.2.:

[0171] .sub.max=390 nm.

Example 5

Ethylene Polymerization Studies

Unsupported [(SBI*)ZrCl.SUB.2.]

[0172] Unsupported rac-SBI*ZrCl.sub.2 was used to catalyse the polymerisation of ethylene at a range of temperatures from 40-90 C. using methylaluminoxane (MAO) as the co-catalyst and scavenger (FIG. 11). The most striking feature of the temperature profile for rac-SBI*ZrCl.sub.2 in solution is the activity achieved at 60 C. (22,622 kg.sub.PE/mol.sub.Zr/h/bar) which compares well with some of the highest reported values in the literature. Another interesting feature is the sharp increase in activity seen between 50 (1,123 kg.sub.PE/mol.sub.Zr/h/bar) and 60 C. (22,622 kg.sub.PE/mol.sub.Zr/h/bar). The weight average molecular weight, M.sub.w, of the resultant polymer was seen to peak at 70 C. (261,337 daltons), up from 213,927 daltons at the activity peak (60 C.). A drop-off is also noted at 80 C. to c. 200,000 daltons. The molecular weight distribution (MWD), measured by the polydispersity index (PDI), was also recorded and was found to increase with increasing temperature from 2.32 (60 C.) to 2.99 (80 C.).

[0173] A study was undertaken with rac-(SBI*)ZrCl.sub.2 to test the effect that the Al:Zr ratio has on activity (FIG. 12) and the value for M.sub.w and M.sub.n, the number average molecular weight, were measured in each case. The polymerisation runs were carried out at 70 C. for ease of comparison since most of the catalysts tested are at or near their optima at this temperature. A very strong dependence of the activity on the Al:Zr ratio was noted, with a linear regression of R.sup.2=0.9862 calculated. The activity at 2000:1 (18,703 kg.sub.PE/mol.sub.Zr/h/bar) is more than four greater than that at 200:1 (3,996 kg.sub.PE/mol.sub.Zr/h/bar). The behaviour of M.sub.w is quite unusual, however. At an Al:Zr ratio of 200, it is recorded as 204,374 daltons rising quickly to 271,713 daltons at a ratio of 500 and plateauing on further increases.

[(SBI*)ZrCl.SUB.2.] Supported on SSMAO and LDHMAO

[0174] The solid-supported [(SBI*)ZrCl.sub.2] catalysts were tested for their ethylene polymerisation activity under slurry conditions in the presence of tri(isobutyl)aluminium (TIBA), an aluminium-based scavenger. The reactions were performed under 2 bar of ethylene in a 200 ml ampoule, with 10 mg of the catalyst suspended in 50 ml of hexane. The reactions were run for 60 minutes at 60 C. and 80 C. controlled by heating in an oil bath. The resulting polyethylene was immediately filtered under vacuum through a dry sintered glass frit. The polyethylene product was then washed with pentane (250 ml) and then dried on the frit for at least one hour. The tests were carried out at least twice for each individual set of polymerisation conditions.

[0175] As shown in Table 1 below, preliminary results demonstrated that ethylene polymerisation using SSMAO-[(SBI*)ZrCl.sub.2] had an activity of 1,173 and 2,160 kg.sub.PE/mol.sub.Zr complex/h at 80 and 60 C. respectively. However, the activity is five times higher at 60 C. using MgAlSO.sub.4/MAO as a support (activity of 11,761 kg.sub.PE/mol.sub.Zr complex/h). The polydispersity is low (M.sub.w/M.sub.n of 2.40) and relatively high molecular weight M.sub.w of 276,905 g/mol.

TABLE-US-00001 TABLE 1 Ethylene polymerisation activity, PE molecular weight and polydispersity for [(SBI*)ZrCl.sub.2] supported on MAO activated silica and MAO activated AMO-layered double hydroxide (MAOLDH) Average activity T (kg.sub.PE/mol.sub.Zr complex/ M.sub.w Support ( C.) h) (g/mol) M.sub.w/M.sub.n SSMAO.sup.a 80 1,173 SSMAO.sup.a 60 2,160 MgAlSO.sub.4/ 60 11,761 276,905 2.40 MAO.sup.b .sup.aSSMAO is MAO activated spherical amorphous silica. .sup.bMgAlSO.sub.4/MAO is an MAO activated AMO-LDH. MgAlSO.sub.4 has the formula [Mg.sub.0.75Al.sub.0.25(OH).sub.2](SO.sub.4).sub.0.1250.55(H.sub.2O)0.13(acetone).

[0176] As shown in Table 2 below, ethylene polymerisation using MgAlSO.sub.4/MAO as a support demonstrated that MgAlSO.sub.4/MAO-[(SBI*)ZrCl.sub.2] had an activity of 11,761 kg.sub.PE/mol.sub.Zr complex/h at 60 C., five and six times higher than ethylene-bridged analogues, [(EBI*)ZrCl.sub.2] and [(EBI)ZrCl.sub.2] (structures shown below), respectively (activity of 2,263 and 1,862 kg.sub.PE/mol.sub.Zr complex/h respectively). Furthermore, the molecular weight for [(SBI*)ZrCl.sub.2] is higher (M.sub.w of 276,905 g/mol) than the two ethylene-bridged complexes (M.sub.w of 251,512 g/mol for [(EBI*)ZrCl.sub.2] and M.sub.w of 213,804 g/mol for [(EBI)ZrCl.sub.2]). The polydispersity is far lower for the permethylated complexes (M.sub.w/M.sub.n<2.40) in comparison with the non-permethylated version (M.sub.w/M.sub.n of 3.76).

TABLE-US-00002 TABLE 2 Ethylene polymerisation activity, PE molecular weight and polydispersity for bridged indenyl complexes supported on MgAlSO.sub.4/MAO; which is a MAO activated AMO-LDH (LDHMAO) T Average activity M.sub.w Support ( C.) (kg.sub.PE/mol.sub.Zr complex/h) (g/mol) M.sub.w/M.sub.n [(EBI)ZrCl.sub.2] 60 1,862 213,804 3.76 [(EBI*)ZrCl.sub.2] 60 2,263 251,512 2.36 [(SBI*)ZrCl.sub.2] 60 11,761 276,905 2.40 MgAlSO.sub.4/MAO is an MAO activated AMO-LDH. The AMO-LDH (MgAlSO.sub.4) has the formula [Mg.sub.0.75Al.sub.0.25(OH).sub.2](SO.sub.4).sub.0.1250.55(H.sub.2O)0.13(acetone). [00023][00024][00025][(EBI)ZrCl.sub.2], [(EBI*)ZrCl.sub.2] and [(SBI*)ZrCl.sub.2]

[0177] FIG. 13 is a graph showing the ethylene polymerisation activity dependence of rac-(SBI*)ZrCl.sub.2 on temperature, supported on SSMAO (200:1 loading) and LDHMAO (300:1 loading). It is clear that the LDH supported catalyst displays a higher activity (953 kg.sub.PE/mol.sub.Zr/h/bar at 70 C.) than that achieved by its silica counterpart (759 kg.sub.PE/mol.sub.Zr/h/bar at 80 C.). The trends identified are similar with an optimum seen in both cases and the activity diminishing on either heating or cooling.

[0178] FIG. 14 is a graph showing the dependence of activity and M.sub.w on temperature for rac-(SBI*)ZrCl.sub.2 supported on SSMAO (200:1 loading). PDIs are given in parentheses. FIG. 14 shows that the molecular weights obtained using rac-(SBI*)ZrCl.sub.2 supported on SSMAO are higher (258,536 daltons; 60 C.) than those obtained using rac-EBI*ZrCl.sub.2 (202,746 daltons; 60 C.). The molecular weight trend for rac-(SBI*)ZrCl.sub.2 on SSMAO sees a decline in molecular weight with increasing temperature.

[0179] FIG. 15 is a graph showing the dependence of activity and M.sub.w on length or run for rac-(SBI*)ZrCl.sub.2 supported on SSMAO (200:1 loading). PDIs are given in parentheses. As with rac-EBI*ZrCl.sub.2, rac-(SBI*)ZrCl.sub.2 on SSMAO was tested to see the effect of increasing the residence time on the activity and M.sub.w. The activity trends in both cases are very similar, with the rate decreasing on increased length of run. However, the relative decrease in activity is not as severe for rac-(SBI*)ZrCl.sub.2: a reduction of 1.4 as opposed to 2.1. The value of M.sub.w drops off at two hours which is not seen for rac-EBI*ZrCl.sub.2 on SSMAO.

[(SBI*)ZrCl.SUB.2.] Supported on Solid MAO

[0180] Ethylene polymerisation studies were also performed using [(SBI*)ZrCl.sub.2] supported on Solid MAO (the solid MAO support is as described in US2013/0059990 and obtainable from Tosoh Finechem Corporation, Japan).

[0181] FIG. 16 is a graph showing the dependence of activity and M.sub.w on temperature for rac-(SBI*)ZrCl.sub.2 supported on Solid MAO (300:1 loading). PDIs are given in parentheses. FIG. 17 is a graph showing the ethylene polymerisation activity dependence on temperature for rac-EBI*ZrCl.sub.2 and rac-(SBI*)ZrCl.sub.2 supported on Solid MAO (200:1 loading for rac-(EBI*)ZrCl.sub.2; 300:1 loading for rac-(SBI*)ZrCl.sub.2). FIGS. 16 and 17 focus on rac-(SBI*)ZrCl.sub.2 immobilised on solid MAOFIG. 16 displaying both activity and molecular weight data with FIG. 17 offering a comparison of the activity with rac-EBI*ZrCl.sub.2. Clearly the activity of rac-(SBI*)ZrCl.sub.2 on Solid MAO is very high, bordering on exceptional in comparison with literature, and peaking at 70 C. (7,760 kg.sub.PE/mol.sub.Zr/h/bar). As outlined above, the best values reported hitherto are Cp.sub.2ZrCl.sub.2, EBTHIZrCl.sub.2, and Cp.sub.2ZrCl.sub.2 which show activities of 5,400, 4,320, and 9,180 kg.sub.PE/mol.sub.Zr/h/bar (all at 60 C.) respectively; all of these bar the dimethylzirconocene dichloride are improved upon by rac-(SBI*)ZrCl.sub.2. In addition, the high activities reported are remarkably temperature stable, maintaining ethylene polymerisation activities in excess of 6,000 kg.sub.PE/mol.sub.Zr/h/bar, and outperforming rac-EBI*ZrCl.sub.2 on Solid MAO, from 50 to 70 C. At either end of the temperature spectrum measured, the activity is seen to dip but still remains as one of the highest activity supported catalysts known in the academic literature.

[0182] It is clear from FIG. 16 that M.sub.w is also high and a value of 288,557 daltons is recorded at 40 C. This decreases rapidly on heating, falling below 150,000 daltons by 90 C. The PDIs narrow in the middle of the temperature range as previously described.

[0183] The synergy of complex and support is clearly demonstrated here as the activities reported for rac-(SBI*)ZrCl.sub.2 on SSMAO and LDHMAO clearly trail those for rac-EBI*ZrCl.sub.2. However, on changing the immobilisation surface to Solid MAO, rac-(SBI*)ZrCl.sub.2 experiences a much more marked improvement than rac-EBI*ZrCl.sub.2. There is a ten-fold increase in performance from SSMAO to Solid MAO for rac-(SBI*)ZrCl.sub.2 compared to just 2.5 times for rac-EBI*ZrCl.sub.2. While this increase is remarkable, the drop from the reported value of 22,622 kg.sub.PE/mol.sub.Zr/h/bar in solution is also very significant.

[0184] In contrast to the large activity variation observed across different media for rac-(SBI*)ZrCl.sub.2, the molecular weight and PDI are comparatively constant (FIG. 18). The well-ordered layered structure of LDHMAO gives rise to high molecular weight polymer and a narrow PDI (297,583 daltons and 2.74). The values for the solution polymerisation and the SSMAO immobilised run are intermediate.

rac-(SBI*.sup.3-ethyl)ZrCl.sub.2 Supported on Solid MAO

[0185] FIGS. 19 and 20 show the polymerisation of ethylene using Solid MAO supported rac-(SBI*.sup.3-ethyl)ZrCl.sub.2 as a function of time and temperature. When comparing these results with earlier data, it is clear that rac-(SBI*)ZrCl.sub.2 is generally 1.5 to 2 times faster than rac-(SBI*.sup.3-ethyl)ZrCl.sub.2 over time and temperature.

Unsupported rac-(SBI*.sup.3-ethyl)ZrCl.sub.2

[0186] FIG. 21 shows the solution polymerisation using unsupported rac-(SBI*.sup.3-ethyl)ZrCl.sub.2 with activity around 11 000 kg.sub.PE/mol.sub.Zr/h/bar, which is close to four times higher than when supported on Solid MAO.

Example 6

Ethylene and -Olefin Polymerization Studies

[0187] In addition to the homo-polymerisation of ethylene, co-polymerisation with 1-hexene was carried out to test the co-monomer incorporation (FIG. 22). It shows a clear co-monomer effect, enhanced activity with respect to the homo-polymerisation up to 5% (v/v) loading of 1-hexene.

[0188] The .sup.13C NMR spectroscopy data for the resulting polymer the rate of 1-hexene incorporation was impressive (Table 3). rac-SBI*ZrCl.sub.2 was able to incorporate effectively double the proportion of co-monomer: 0.4 and 0.8 mol % at 5 and 10% concentrations of 1-hexene respectively. As well as improved levels of 1-hexene incorporation, rac-SBI*ZrCl.sub.2 maintains high molecular weights on addition of co-monomer at all concentrations (Table 4).

TABLE-US-00003 TABLE 3 1-hexene incorporation (mol %) into the final polymer as determined by .sup.13C NMR spectroscopy at different concentrations of co-monomer. 5% (v/v) 1-hexene 10% (v/v) 1-hexene 1-hexene incorporation 1-hexene incorporation Catalyst (mol %) (mol %) rac-SBI * ZrCl.sub.2 0.4 0.8 Polymerisation conditions: supported on Solid MAO (300:1); 70 C.; 5 ml heptane; 15 mol AlEt.sub.3; 8.274 bar ethylene; 0.1-0.5 mg catalyst.

TABLE-US-00004 TABLE 4 M.sub.w (daltons) and PDI data for the final polymer as determined by GPC at different concentrations of 1-hexene. 2% (v/v) 5% (v/v) 10% (v/v) 1-hexene 1-hexene 1-hexene Catalyst M.sub.w PDI M.sub.w PDI M.sub.w PDI rac-SBI * ZrCl.sub.2 384,000 4.4 302,000 3.3 244,000 2.8 rac-SBI * ZrCl.sub.2 384,000 4.4 302,000 3.3 244,000 2.8 Polymerisation conditions: supported on Solid MAO (300:1); 70 C.; 5 ml heptane; 15 mol AlEt.sub.3; 8.274 bar ethylene; 0.1-0.5 mg catalyst

[0189] Further to the characterisation by .sup.13C NMR spectroscopy, the co-polymer was analysed by crystallisation elution fractionation (CEF). This corroborated the 1-hexene incorporation data as well as analysing the amorphous fractions (AF) and temperatures of melting (Table 5).

TABLE-US-00005 TABLE 5 Temperature at maximum elution ( C.) and amorphous fraction (%) data for the final polymer as determined by CEF at different concentrations of 1-hexene. 2% (v/v) 5% (v/v) 10% (v/v) 1-hexene 1-hexene 1-hexene T.sub.el. max. AF T.sub.el. max. AF T.sub.el. max. AF Catalyst ( C.) (%) ( C.) (%) ( C.) (%) rac-SBI*ZrCl.sub.2 111.3 110.4 109.2 Polymerisation conditions: supported on Solid MAO (300:1); 70 C.; 5 ml heptane; 15 mol AlEt.sub.3; 8.274 bar ethylene; 0.1-0.5 mg catalyst.

[0190] The data for the temperature at maximum elution (T.sub.el. max.) fits very well with the 1-hexene incorporation data: T.sub.el. max. decreases as the proportion of 1-hexene in the co-polymer rises. Poly(1-hexene) has a much lower glass transition temperature (T.sub.g) and melting temperature than PE, and this is reflected in the reduction of T.sub.el. max. with increasing 1-hexene concentration. At 0.8% incorporation, the temperature of elution has decreased to 109.2 C. (rac-SBI*ZrCl.sub.2 at 10% 1-hexene). Viscosity measurements were also recorded and these were found to be in good agreement with the molecular weight data obtained by GPC.

[0191] While specific embodiments of the invention have been described herein for the purpose of reference and illustration, various modifications will be apparent to a person skilled in the art without departing from the scope of the invention as defined by the appended claims.