INORGANIC POROUS FRAMEWORK-LAYERED DOUBLE HYDROXIDE CORE-SHELL MATERIALS AS CATALYST SUPPORTS IN ETHYLENE POLYMERISATION

Abstract

A catalyst system comprises an activated solid support material and having, on its surface, one or more catalytic transition metal complexes.

Claims

1. A catalyst system comprising an activated solid support material and having, on its surface, one or more catalytic transition metal complex, wherein the solid support material comprises a core@layered double hydroxide shell material having the formula I
T.sub.p @ {[M.sup.z+.sub.(1x)M.sub.x.sup.y+(OH).sub.2].sup.a+(X.sup.n).sub.a/n.bH.sub.2O.c(AMO-solvent)}.sub.q (I) wherein T is a solid, porous, inorganic oxide-containing framework material, M.sup.z+ and M.sup.y+ are independently selected charged metal cations; M.sup.z+ is a metal cation of charge z or a mixture of two or more metal cations each independently having the charge z; M.sup.y+ is a metal cation of charge y or a mixture of two or more metal cations each independently having the charge y; z=1 or 2; y=3 or 4; 0<x<0.9; b is 0 to 10; c is 0.01 to 10; p>0; q>0; X.sup.n is an anion; with n>0; a=z(1x)+xy2; and AMO-solvent is an organic solvent which is completely miscible with water.

2. The catalyst system according to claim 1, wherein M is Al, and/or M is Li, Mg or Ca and/or X.sup.n is selected from CO.sub.3.sup.2, OH.sup., F.sup., Cl.sup., Br.sup., I.sup., SO.sup.2, NO.sub.3.sup. and PO.sub.4.sup.3, preferably CO.sub.3.sup.2, Cl.sup. and NO.sub.3.sup., or mixtures thereof.

3. The catalyst system according to claim 1, wherein the AMO-solvent is selected from acetone, methanol, ethanol or isopropanol, preferably acetone or ethanol.

4. The catalyst system according to claim 1, wherein T is a molecular sieve material selected from silicate, aluminium silicate, vanadium silicate, iron silicate, silicon-aluminium phosphate (SAPO) and aluminium phosphate (AIPO).

5. The catalyst system according to claim 1, wherein T is an aluminium silicate having a silicon:aluminium ratio of from 1 to 100, preferably 25 to 100, more preferably 30 to 50.

6. The catalyst system according to claim 1, wherein the aluminium silicate has a framework structure selected from zeolite types A, X, Y, BEA, MOR and MFI, and/or the aluminium silicate has a framework structure containing non-framework organic and/or inorganic cations, wherein the non-framework organic and inorganic cations are preferably selected from NR.sub.4.sup.+, where R is an optionally-substituted alkyl group, Na.sup.+, K.sup.+ and Cs.sup.+.

7. The catalyst system according to claim 1, wherein the catalytic transition metal complex is at least one complex of a metal selected from zirconium, iron, chromium, cobalt, nickel, titanium and hafnium, the complex containing one or more aromatic or heteroaromatic ligands, preferably is a metallocene containing zirconium or hafnium.

8. The catalyst system according to claim 1, wherein the catalyst systems comprise an activated solid support material and having, on its surface, one or more catalytic transition metal complexes, wherein the catalytic transition metal complex is a metallocene containing zirconium or hafnium; and wherein the solid support material comprises a core@layered double hydroxide shell material having the formula IIc
T.sub.p@ {[M.sup.z+.sub.(1x)M.sup.y+.sub.x(OH).sub.2].sup.a+(X.sup.n).sub.a/n.bH.sub.2O.c(ethanol)}.sub.q (IIC) wherein, T is; i) an aluminium silicate with a framework structure selected from zeolite types LTA, FAU, BEA, MOR or MFI; ii) an aluminophosphate; iii) a silicoaluminophosphate; or iv) a mesoporous silicate, wherein the aluminium silicate has a silicon:aluminium ratio of from 1 to 50, more preferably of 1 to 40, most preferably of 1 to 30; M.sup.z+ is selected from Li.sup., Ca.sup.2+, Cu.sup.2+, Zn.sup.2+, Ni.sup.2+ or Mg.sup.2+, and M.sup.y+ is Al.sup.3+, Ga.sup.3+, In.sup.3+, or Fe.sup.3+; 0<x<0.9; b is 0 to 10; c is 0.01 to 10; p>0, q>0; X.sup.n is is selected from CO.sub.3.sup.2, NO.sub.3.sup. or Cl.sup.; with n>0 (preferably 1-5) a=z(1x)+xy2.

9. The catalyst system according to claim 1, wherein activating to achieve the activated catalyst is activating the solid support material with an alkylaluminoxane, preferably methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), or trisobutylaluminium (TIBA), triethylaluminium (TEA) or diethylaluminium chloride (DEAC).

10. A method of making the catalyst system according to claim 1, which comprises (a) providing a solid support material comprising a core@layered double hydroxide shell material having the formula I
T.sub.p @ {[M.sup.z+.sub.(1x)M.sub.x.sup.y+(OH).sub.2].sup.a+(X.sup.n).sub.a/n.bH.sub.2O.c(AMO-solvent)}.sub.q (I) wherein T is a solid, porous, inorganic oxide-containing framework material, M.sup.z+ and M.sup.y+ are two independently selected charged metal cations; M.sup.z+ is a metal cation of charge z or a mixture of two or more metal cations each independently having the charge z; M.sup.y+ is a metal cation of charge y or a mixture of two or more metal cations each independently having the charge y; z=1 or 2; y=3 or 4; 0<x<0.9; b is 0 to 10; c is 0.01 to 10; p>0; q>0; X.sup.n is an anion; with n>0; a=z(1x)+xy2; and AMO-solvent is an organic solvent which is completely miscible with water; and (b) thermally treating the core@layered double hydroxide shell material; (c) activating the material obtained from the thermal treatment step (b); and (d) treating the activated material obtained from step (c) with at least one catalytic transition metal complex having olefin polymerisation catalytic activity.

11. The method according to claim 10, wherein the catalytic transition metal complex is at least one complex of a metal selected from zirconium, iron, chromium, cobalt, nickel, titanium and hafnium, the complex containing one or more aromatic or heteroaromatic ligands.

12. The method according to claim 10, further comprising a step of calcining the core@AMO-LDH microparticles before the treating step (b).

13. The method according to claim 10, further comprising a step of treating the calcined core@AMO-LDH microparticles with an alkylaluminoxane, preferably methylaluminoxane (MAO) and/or modified methylaluminoxane (MMAO), before the treating step (b).

14. A use of a catalyst system according to claim 1 in combination with a suitable scavenger as a catalyst in the polymerisation and/or copolymerisation of at least one olefin for producing a homopolymer and/or copolymer, preferably comprising 1-10 wt % of a (4-8C) -olefin, thereof.

15. A use of a catalyst system according to claim 14, where a suitable scavenger is an alkylaluminoxane, preferably methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), or trisobutylaluminium (TIBA), triethylaluminium (TEA), or diethylaluminium chloride (DEAC).

16. A process for preparing a polyolefin homopolymer or a polyolefin copolymer which comprises reacting olefin monomers in the presence of a catalyst system according to claim 1, wherein the polyolefin is preferably polyethylene and the olefin monomer is preferably ethylene.

17. A process for producing a polymer of an olefin, preferably ethylene, which comprises contacting the olefin with the solid catalyst system according to claim 1.

18. The process according to claim 16, wherein the process is performed at a temperature of 50-100 C., most preferably 70 to 80 C.

Description

FIGURES

[0274] FIG. 1. TEM images of (a) zeolite HY5.1 and (b) HY5.1 @ AMO-LDH

[0275] FIG. 2. Thermal analysis data for the zeolite@layered double hydroxide shell material (HY5.1 @ AMO-LDH) showing the thermal events on heating. [0276] LeftThermogravimetric Analysis (TGA), where (a) is HY 5.1, (b) is HY 5.1@LDA-A and (c) is LDH-A. [0277] Rightderivative Thermogravimetric Analysis (dTGA), where (a) is HY 5.1, (b) is HY 5.1@LDA-A and (c) is LDH-A. [0278] LDH-A denotes AMO-synthesised LDH using acetone treatment.

[0279] FIG. 3. Pore size distribution of HY5.1 and HY5.1 @ AMO-LDH after calcination at 300 C., where (a) is HY5.1 and (b) is HY5.1@LDH-A and LDH-A denotes AMO-synthesised LDH.

[0280] FIG. 4. TEM images of HY5.1 @ LDH [0281] top shows water-washed product [0282] bottom shows acetone-washed product [0283] LDH-W denotes conventionally-synthesised LDH, LDH-A denotes AMO-synthesized LDH.

[0284] FIG. 5. X-ray powder diffraction of HY5.1 @ LDH [0285] Lefta comparison with starting material, where (a) is HY5.1, (b) is HY5.1@LDH-A and (c) is LDH-A. [0286] Righta comparison between water- and acetone-washed samples, where (a) is HY5.1@LDH-W and (b) is HY5.1@LDH-A. [0287] LDH-W denotes conventionally synthesised LDH, LDH-A denotes AMO-synthesised LDH.

[0288] FIG. 6. Thermal analysis data for the zeolite@layered double hydroxide shell material, HY5.1 @ LDH, showing the thermal events on heating. [0289] LeftThermogravimetric Analysis (TGA), where the solid line is HY(5.1)@LDH-W and the dashed line is HY(5.1)@LDH-A. [0290] Rightderivative Thermogravimetric Analysis (dTGA), where the solid line is HY(5.1)@LDH-W and the dashed line is HY(5.1)@LDH-A. [0291] LDH-W denotes conventionally-synthesised LDH, LDH-A denotes AMO-synthesised LDH with acetone treatment.

[0292] FIG. 7. TEM images of HY @ AMO-LDH. [0293] AMOST method treatment using acetone as the AMO solvent.

[0294] FIG. 8. TEM images of HY30 @ AMO-LDH. [0295] AMOST method treatment using acetone as the AMO solvent.

[0296] FIG. 9. TEM images of HY15 @ AMO-LDH. [0297] AMOST method treatment using acetone as the AMO solvent.

[0298] FIG. 10. TEM images of ZSM5 @ AMO-LDH. [0299] AMOST method treatment using acetone as the AMO-solvent.

[0300] FIG. 11. TEM images of ZSM5-23 @ LDH at a rate of 60 ml/hr drop rate.

[0301] FIG. 12. TEM images of ZSM5-40 @ LDH at rates of 60 ml/hr, 40 ml/hr and 20 ml/hr drop rates.

[0302] FIG. 13. Thermal analysis data for the zeolite@layered double hydroxide shell material, ZSM5-23 @ LDH, showing the thermal events on heating. [0303] LeftThermogravimetric Analysis (TGA), where the solid line is LDH-A, the dashed line is ZSM-5(23)@LDH-A and the dotted line is ZSM-5(23). [0304] Rightderivative Thermogravimetric Analysis (dTGA), where the solid line is LDH-A, the dashed line is ZSM-5(23)@LDH-A and the dotted line is ZSM-5(23). [0305] AMOST method treatment using acetone as the AMO-solvent. LDH-A denotes AMO-synthesised LDH using acetone treatment.

[0306] FIG. 14. Thermal analysis data for the zeolite@layered double hydroxide shell material, ZSM5-23 @ LDH, [0307] Leftacetone-washed, where the squared line is ZSM-5(23), the circled line is ZSM-5(23)@LDH-A and the triangular line is LDH-A. [0308] Rightwater-washed, where the squared line is ZSM-5(23), the circled line is ZSM-5(23)@LDH-W and the triangular line is LDH-W [0309] LDH-A denotes AMO-synthesised LDH using acetone treatment and LDH-W denotes conventionally synthesised LDH.

[0310] FIG. 15. Represents the different BET values at various calcination temperatures using HY5.1 @ LDH demonstrating no particular change.

[0311] FIG. 16. TEM image of HY5.1@Mg.sub.2AlNO.sub.3 LDH-A. LDH-A denotes AMO-synthesised LDH, [0312] Left1 m scale zoom [0313] Right500 nm scale zoom.

[0314] FIG. 17. X-Ray powder diffraction of HY5.1@Mg.sub.2AlNO.sub.3 LDH-A. LDH-A denotes AMO-synthesised LDH.

[0315] FIG. 18. Thermogravimetric Analysis (TGA) of (a) HY5.1, (b) HY5.1@ Mg.sub.2AlNO.sub.3 LDH-A and (c) LDH-A. LDH-A denotes AMO-synthesised LDH.

[0316] FIG. 19. Two TEM images of HY5.1@ Mg.sub.2Al.sub.0.8Fe.sub.0.2CO.sub.3 LDH-A. LDH-A denotes AMO-synthesised LDH.

[0317] FIG. 20. X-Ray powder diffraction of HY5.1@ Mg.sub.2Al.sub.0.8Fe.sub.0.2CO.sub.3 LDH-A. LDH-A denotes AMO-synthesised LDH.

[0318] FIG. 21. Thermogravimetric Analysis (TGA) of (a) HY5.1, (b) HY5.1@ Mg.sub.2Al.sub.0.8Fe.sub.0.2CO.sub.3 LDH-A and (c) LDH-A. LDH-A denotes AMO-synthesised LDH.

[0319] FIG. 22. Two TEM images of HY5.1@ Mg.sub.1.8AlNi.sub.0.2CO.sub.3 LDH-A. LDH-A denotes AMO-synthesised LDH.

[0320] FIG. 23. X-Ray powder diffraction of HY5.1@ Mg.sub.1.8AlNi.sub.0.2CO.sub.3 LDH-A. LDH-A denotes AMO-synthesised LDH.

[0321] FIG. 24. Thermogravimetric Analysis (TGA) of (a) HY5.1, (b) HY5.1@ Mg.sub.1.8AlNi.sub.0.2CO.sub.3 LDH-A and (c) LDH-A. LDH-A denotes AMO-synthesised LDH.

[0322] FIG. 25. X-Ray powder diffraction of MSN@LDH (a) MCM-41@AMO-LDH (b) SBA-15@AMO-LDH.

[0323] FIG. 26. TEM images of (a, b) MCM-41@AMO-LDH and (c, d) SBA-15@AMO-LDH.

[0324] FIG. 27. X-Ray powder diffraction of Microporous Aluminophosphate @LDH: (a)ALPO-5@AMO-LDH, (b)SAPO-5@AMO-LDH.

[0325] FIG. 28. Two TEM images of SAPO-5@AMO-LDH.

[0326] FIG. 29. Two TEM images of ALPO-5@AMO-LDH.

[0327] FIG. 30. Ethylene polymerisation data using HY5.1 @LDH/MAO/(EBI)ZrCl.sub.2 (square), LDH/MAO/(EBI)ZrCl.sub.2 (triangle) and pure HY5.1/MAO/(EBI)ZrCl.sub.2 (circle).

[0328] FIG. 31. Ethylene polymerisation data using ZSMS-23@LDH/MAO/(EBI) (square), LDH/MAO/(EBI)ZrCl.sub.2 (triangle), ZSMS-23/MAO/(EBI) ZrCl.sub.2 (circle).

EXAMPLES

[0329] Experimental Methods

[0330] 1. General Details

[0331] 1.1 Powder X-Ray Diffraction

[0332] Powder X-ray diffraction (XRD) data were collected on a PANAnalytical X'Pert Pro diffractometer in reflection mode and a PANAnalytical Empyrean Series 2 at 40 kV and 40 mA using Cu Ka radiation (1=1.54057 , 2=1.54433 , weighted average=1.54178 ). Scans were recorded from 5070 with varying scan speeds and slit sizes. Samples were mounted on stainless steel sample holders. The peaks at 43-44 are produced by the XRD sample holder and can be disregarded.

[0333] 1.2 Thermogravimetric Analysis

[0334] Thermogravimetric analysis (TGA) measurements were collected using a Netzsch STA 409 PC instrument. The sample (10-20 mg) was heated in a corundum crucible between 30 C. and 800 C. at a heating rate of 5 C. min.sup.1 under a flowing stream of nitrogen.

[0335] 1.3 Transmission Electron Microscopy

[0336] Transmission Electron Microscopy (TEM) analysis was performed on a JEOL 2100 microscope with an accelerating voltage of 200 kV. Particles were dispersed in water or ethanol with sonication and then cast onto copper grids coated with carbon film and left to dry.

[0337] 1.4 Brunauer-Emmett-Teller Surface Area Analysis

[0338] Brunauer-Emmett-Teller (BET) specific surface areas were measured from the N2 adsorption and desorption isotherms at 77 K collected from a Quantachrome Autosorb surface area and pore size analyser.

[0339] General Method of Synthesis of Catalyst Support Material

[0340] Zeolite (100 mg) was dispersed in deionised water (20 mL) using ultrasound treatment. After 30 minutes, the sodium carbonate was added to the solution and a further 6 minutes of sonication was carried out to form solution A. An aqueous solution (19.2 mL) containing magnesium nitrate hexahydrate and aluminium nitrate nonahydrate was added at a rate of 60 mL/h to solution A under vigourous stirring. The pH of the reaction solution was controlled with the addition of 1 M NaOH by an autotitrator. The obtained suspension was stirred for 1 h. The obtained solid was collected and then re-dispersed in deionised water (40 mL) and stirred for 1 h. The collection and re-dispersion was repeated once. The samples (Zeolite@LDH) were then dried under vacuum. The Zeolite@AMO-LDH was synthesized using the same procedure. However, before final isolation, the solid was treated with AMOST method, which was washed with acetone (40 mL) and then re-dispersed in acetone (40 mL) under stirring for overnight. The solid was then dried under vacuum for materials characterization.

[0341] Using this general method, zeolite@LDH shell materials were synthesised using the different zeolite types HY5.1, HY30, HY15, ZSM5, ZSM5-23 and ZSM5-40.

[0342] The zeolite@LDH shell materials obtained using these different zeolite types were characterised and/or studied according to the following.

[0343] Characterisation of HY5.1@LDH

[0344] The zeolite HY5.1 was used to attempt the synthesis of the first Zeolite@AMO-LDH. FIGS. 1 and 2 highlight the synthesis and characterisation of HY5.1@AMO-LDH. Acetone was used as the AMO-solvent. The AMO-LDH can fully coat the surface of HY5.1 with open hierarchical structure. The content of LDH is around 61.5% according to the TGA result. After thermal treatment at 300 C., the total surface area of HY5.1@AMO-LDH is similar to that of pure HY5.1 as shown in Table 1. The external surface area increased close to three times (70 to 201 m.sup.2/g) and the accumulate volume increased from 0.07 to 0.66 cc/g. While the micropore surface area dropped from 625 to 497 m.sup.2/g.

[0345] Comparison between HY5.1@AMO-LDH and HY5.1@LDH

[0346] A similar procedure was used to synthesise and characterise zeolite core-shell material using conventionally synthesised LDH, HY5.1@LDH, FIG. 4. The morphology of HY5.1@LDH-W and HY5.1@LDH-A are similar.

[0347] FIG. 5 and FIG. 6 are the XRD and TGA results from conventional and AMO-synthesised HY5.1@LDH. Both samples show similar crystallinity and weight loss.

[0348] Variation of Si/Al Ratio in HY@AMO-LDH

[0349] FIG. 7 shows the increased affinity for LDH with increased aluminium content, providing a better Al.sup.3+ source for LDH growth.

[0350] Variation of Other Parameters using HY30@LDH

[0351] The coating of LDH on the HY30 surface did not increase by changing temperature and Mg/Al ratio. However, a change in pH and Na.sub.2CO.sub.3 soaking time demonstrated a small improvement in affinity of LDH on the surface.

[0352] Variation of Zeolite to LDH Ratio in HY15@AMO-LDH

[0353] FIG. 9 shows that for HY15, 200 mg seems to possess the best coating of the three. 90% of HY15 has been coated with dense LDH layer when using 200 mg.

[0354] Variation of Si/Al Ratio in ZSM5@LDH

[0355] LDH can easily grow on the surface of ZSM5 regardless of the Si/Al ratio.

[0356] Variation of Zeolite to LDH Ratio in ZSM5-23@LDH

[0357] By increasing the amount of ZSM5-23, the free LDH was reduced. However, less ZSM5 was coated with LDH.

[0358] Variation of the Drop Rate in ZSM5-40@LDH

[0359] Change in the drop rate has no significant effect.

[0360] Characterisation of ZSM5-23@AMO-LDH

[0361] FIG. 13 shows around 50% LDH in the sample ZSM5-23@AMO-LDH.

TABLE-US-00001 TABLE 1 Summary data from N2 adsorption and desorption Cumu- BET External Micropore Micropore lative SSA SSA SSA volume Volume Samples (m.sup.2/g) (m.sup.2/g) (m.sup.2/g) (cc/g) (cc/g) HY5.1 813 72 740 0.28 0.08 HY5.1@LDH-W 565 164 401 0.17 0.60 HY5.1@LDH-W 698 497 LDH-W 11 0.4 11 0.004 0.04 LDH-A 281 252 29 0.01 1.08 ZSM5-23 424 45 379 0.15 0.05 ZSM5-23@LDH-W 167 54 113 0.04 0.33 ZSM5-23@LDH-A 339 140 199 0.08 0.05 HY5.1 300 C. 695 70 625 0.30 0.07 HY5.1@LDH-A 698 201 497 0.23 0.66 300 C.

[0362] LDH-W means the LDH was prepared by the conventional method in water. LDH-A means the LDH was treated with acetone.

[0363] FIG. 15 represents the different BET values at various calcination temperatures using HY5.10LDH demonstrating no particular change.

[0364] Further Core @ Layered Double Hydroxide Shell Materials

[0365] Variation of the Anion of the LDH

[0366] Example Method of HY5.1@Mg.sub.2AlNO.sub.3 LDH-A

[0367] HY5.1 (100 mg) was dispersed in deionised water (20 mL) using ultrasound treatment. After 36 minutes, an aqueous solution (19.2 mL) containing magnesium nitrate hexahydrate and aluminium nitrate nonahydrate was added at a rate of 60 mL/h to HY5.1 solution under vigour stirring. The pH of the reaction solution was controlled to 10 with the addition of 1 M NaOH by an autotitrator. The obtained suspension was stirred for 1 h. The obtained solid was collected and then re-dispersed in deionised water (40 mL) and stirred for 1 h. The collection and re-dispersion was repeated once. The solid was treated with AMOST method, which was washed with acetone (40 mL) and then re-dispersed in a fresh acetone (40 mL) under stirring for overnight. The solid was then dried under vacuum oven for materials characterization.

[0368] Characterisation

[0369] HY5.1@Mg.sub.2AlNO.sub.3 LDH

[0370] The same synthesis method is applied to LDH-NO3. The TEM (FIG. 16) show that the Mg.sub.2AlNO.sub.3 LDH-A can grow on the surface of HY5.1. However, the amount of LDH on the surface is less, compared to LDH-CO.sub.3 when using the same conditions. The XRD (FIG. 17) indicates that HY5.10 Mg.sub.2AlNO.sub.3 LDH-A has both characterization peaks of HY5.1 and LDH. TGA (FIG. 18) shows that HY5.10 Mg.sub.2AlNO.sub.3 LDH-A exhibits the typical three decompose stage of LDH.

[0371] Variation of the Metal of the LDH

[0372] Example Method of HY5.1@ Mg.sub.2Al.sub.0.8Fe.sub.0.2CO.sub.3 LDH-A

[0373] HY5.1 (100 mg) was dispersed in deionised water (20 mL) using ultrasound treatment. After 36 minutes, an aqueous solution (19.2 mL) containing magnesium nitrate hexahydrate, iron nitrate nonahydrate and aluminium nitrate nonahydrate (Mg:Al:Fe 2:0.8:0.2) was added at a rate of 60 mL/h to HY5.1 solution under vigour stirring. The pH of the reaction solution was controlled to 10 with the addition of 1 M NaOH by an autotitrator. The obtained suspension was stirred for 1 h. The obtained solid was collected and then re-dispersed in deionised water (40 mL) and stirred for 1 h. The collection and re-dispersion was repeated once. The solid was treated with AMOST method, which was washed with acetone (40 mL) and then re-dispersed in a fresh acetone (40 mL) under stirring for overnight. The solid was then dried under vacuum oven for materials characterization.

Characterisation

[0374] HY5.1@Mg.sub.2Al.sub.0.8Fe.sub.0.2CO.sub.3 LDH

[0375] The TEM (FIG. 19) show that the Mg.sub.2Al.sub.0.8Fe.sub.0.2CO.sub.3 LDH can grow on the surface of HY5.1. The XRD (FIG. 20) indicates that HY5.1@ Mg.sub.2Al.sub.0.8Fe.sub.0.2CO.sub.3 LDH-A has both characterization peaks of HY5.1 and LDH. TGA (FIG. 21) shows that HY5.1@ Mg.sub.2Al.sub.0.8Fe.sub.0.2CO.sub.3 LDH-A exhibits the typical three decompose stage of LDH.

[0376] Example Method of HY5.1@ Mg1.8AlNi.sub.0.2CO.sub.3 LDH-A

[0377] HY5.1 (100 mg) was dispersed in deionised water (20 mL) using ultrasound treatment. After 36 minutes, an aqueous solution (19.2 mL) containing magnesium nitrate hexahydrate, nickel nitrate hexahydrate and aluminium nitrate nonahydrate (Mg:Al:Ni 1.8:1:0.2) was added at a rate of 60 mL/h to HY5.1 solution under vigour stirring. The pH of the reaction solution was controlled to 10 with the addition of 1 M NaOH by an autotitrator. The obtained suspension was stirred for 1h. The obtained solid was collected and then re-dispersed in deionised water (40 mL) and stirred for 1 h. The collection and re-dispersion was repeated once. The solid was treated with AMOST method, which was washed with acetone (40 mL) and then re-dispersed in a fresh acetone (40 mL) under stirring for overnight. The solid was then dried under vacuum oven for materials characterization.

[0378] Characterisation

[0379] HY5.1@Mg.sub.1.8AlNi.sub.0.2CO.sub.3 LDH

[0380] The TEM (FIG. 22) show that the Mg.sub.1.8AlNi.sub.0.2-CO.sub.3 LDH-A can grow on the surface of HY5.1. The XRD (FIG. 23) indicates that HY5.1@ Mg.sub.1.8AlNi.sub.0.2CO.sub.3 LDH-A has both characterization peaks of HY5.1 and LDH. TGA (FIG. 24) shows that HY5.1@ Mg.sub.1.8AlNi.sub.0.2CO.sub.3 LDH-A exhibits the typical three decompose stage of LDH.

[0381] Mesoporous Silica Based Materials

[0382] Example Method of MSN@ Mg.sub.3AlCO.sub.3 LDH

[0383] Generally, MCM-41 (50 mg) was dispersed in deionised water (20 mL) using ultrasound treatment. After 30 minutes, the sodium carbonate was added to the solution and a further 6 minutes of sonication was carried out to form solution A. An aqueous solution (19.2 mL) containing magnesium nitrate hexahydrate and aluminium nitrate nonahydrate was added at a rate of 60 mL/h to solution A under vigorous stirring. The pH of the reaction solution was controlled with the addition of 1 M NaOH by an autotitrator. The obtained suspension was stirred for 1 h. The obtained solid was collected and then re-dispersed in deionised water (40 mL) and stirred for 1 h. The collection and re-dispersion was repeated once. Before final isolation, the solid was treated with AMOST method, which was washed with acetone (40 mL) and then re-dispersed in acetone (40 mL) under stirring for overnight. The samples (MCM-41@AMO-LDH) were then dried under vacuum. The other MSN@AMO-LDH (such as SBA-15@AMO-LDH) was synthesized using the same procedure.

[0384] Characterisation

[0385] MSN@Mg3AlCO.sub.3 LDH

[0386] According to X-ray diffraction (XRD) pattern (FIG. 25) of MSN@LDH, the core of MCM-41 has a mean pore diameter about 3 nm and SBA-15 has a mean pore diameter about 9 nm. The XRD pattern of low angle (Figure S25 inset) showed that the samples had an high ordered hexagonal structure and high crystallinity, these Bragg peaks can be indexed as (100), and overlapped (110) of the two-dimensional hexagonal mesostructure (space group p6m). Since MCM-41 and SBA-15 consists of amorphous silica, it has no crystallinity at the atomic level. Therefore, only the typical peaks of LDH have been observed at higher degrees. We can observe from the TEM images (FIG. 26) that LDH-nanosheet can grow on the Mesoporous Silica Nanoparticles surface.

[0387] Microporous Molecular Sieves @ LDH

[0388] Example Method of ALPO-5/SAPO-5@LDH

[0389] Generally, ALPO-5(100 mg) was dispersed in deionised water (20 mL) using ultrasound treatment. After 30 minutes, the sodium carbonate was added to the solution and a further 6 minutes of sonication was carried out to form solution A. An aqueous solution (19.2 mL) containing magnesium nitrate hexahydrate and aluminium nitrate nonahydrate was added at a rate of 60 mL/h to solution A under vigorous stirring. The pH of the reaction solution was controlled with the addition of 1 M NaOH by an autotitrator. The obtained suspension was stirred for 1 h. The collection and re-dispersion was repeated once. Before final isolation, the solid was treated with AMOST method, which was washed with acetone (40 mL) and then re-dispersed in acetone (40 mL) under stirring for overnight. The samples (ALPO-5@AMO-LDH) were then dried under vacuum. The SAPO-5@AMO-LDH was synthesized using the same procedure.

[0390] SAPO5@Mg.sub.3AlCO.sub.3 LDH & ALPO5@Mg.sub.3AlCO.sub.3 LDH

[0391] XRD (FIG. 27) shows typical peaks of ALPO-5/SAPO-5 which is an AFI-type. On the other hand, typical peaks of LDH have been also observed at higher degrees. TEM images (FIGS. 28 and 29) show that LDH can grow on the surface of ALPO and SAPO. However, the thickness is depended on the composites of materials and synthesis method. For example, ALPO with higher Al content could have thicker layer of LDH, comparing SAPO.

[0392] Polymerisation of Ethylene Using Zeolite@LDH

[0393] Synthesis of ZSM5-23/MAO and ZSM5-23@LDH/MAO

[0394] A sample of ZSM5-23@LDH, prepared as described above, was thermally treated at 150 C. for 6 h before being reacted with methylaluminoxane (MAO) in a 2:1 ratio (support:MAO) in toluene at 80 C. for 2 h. The solvent was removed under vacuum to give ZSM5-23@LDH/MAO as a free-flowing colourless powder.

[0395] A sample of the zeolite ZSM5-23 was also thermally treated and then reacted with MAO, according to the procedure described above. Following removal of the solvent, the solid product ZSM5-23/MAO was obtained.

[0396] Synthesis of Catalysts Based on ZSM5-23

[0397] The ZSM5-23@LDH/MAO, obtained as described above, was reacted with rac-(EBI)ZrCl.sub.2 in a 200:1 ratio (support/MAO:(EBI)ZrCl.sub.2) in toluene. The reaction was carried out at 60 C. for 1 h. After removing the solvent, the beige solid product ZSM5-23@LDH/MAO/(EBI)ZrCl.sub.2 was obtained. The same process was carried out with the ZSM5-23/MAO to give ZSM5-23/MAO/(EBI)ZrCl.sub.2. In addition, the same process was carried out using, as support, LDH/MAO to give the product LDH/MAO/(EBI)ZrCl.sub.2.

[0398] Ethylene Polymerisation Studies

[0399] The catalysts were tested for their ability to act as a catalyst for ethylene polymerisation under slurry conditions in the presence of TIBA (TIBA).sub.0/[Zr].sub.0=1000). The reactions were performed with ethylene (2 bar) in a 200 mL ampoule, with the catalyst precursor (10 mg) suspended in hexane (50 mL). The reactions were run for 15-120 minutes at 50-90 C. controlled by heating in an oil bath. The polyethylene product was washed with pentane (350 mL) and the resulting polyethylene was filtered through a sintered glass frit.

[0400] The polymerisation activity of the catalyst supported metallocene complexes plotted against temperature is shown in FIG. 30 and FIG. 31.

[0401] FIG. 31 shows that ZSM5-23@LDH/MAO/(EBI)ZrCl.sub.2 is better than ZSM5-23/MAO/(EBI)ZrCl.sub.2 and LDH/MAO/(EBI)ZrCl.sub.2. Furthermore, there is the same tendency to go higher in activity with higher temperature.

[0402] Catalysts were also produced using the zeolite HY5.1 according to the processes described above. Each of these catalysts, HY5.1@LDH/MAO/(EBI)ZrCl.sub.2, LDH/MAO/(EBI)ZrCl.sub.2 and pure HY5.1/MA0/(EBI)ZrCl.sub.2, was also tested for its ability to act as a catalyst for ethylene polymerisation as described above. The polymerisation activities of these plotted against temperature are shown in FIG. 30. In this Figure, it is shown that when the coverage of the zeolite@LDH is too complete, the HY5.1@LDH/MAO/(EBI) ZrCl.sub.2 acts similarly as LDH/MAO/(EBI)ZrCl.sub.2 and is lower than pure HY5.1/MAO/(EBI)ZrCl.sub.2.

[0403] The features disclosed in the foregoing description, in the claims and in the accompanying drawings may, both separately and in any combination, be material for realising the invention in diverse forms thereof.

[0404] 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