Supported polymerisation catalysts
View Patent ↗A supported polymerisation catalyst system comprises a porous support, a polymerisation catalyst and a cocatalyst wherein the support has been treated with an inert material such as polyisobutene. The support is preferably silica and is preferably treated with the inert material prior to contact with the other components. Preferably the polymerisation catalyst is a metallocene and the polymerisation catalyst system reduces the initial peak isotherm allowing for a smoother activity increase in particular for polymerisations carried out in the gas phase.
1. A supported polymerisation catalyst system comprising the combination of
(i) a porous support,
(ii) a polymerisation catalyst, and
(iii) a cocatalyst,
the porous support is treated with an inert material prior to contact of the porous support with the other catalyst components and in an amount of less than or equal to the pore volume of the porous support.
2. A supported polymerisation catalyst system according to claim 1 wherein the inert material is chosen from hydrocarbon liquids, oils or waxes.
3. A supported polymerisation catalyst system according to claim 2 wherein the hydrocarbon liquid is a C 5 -C 8 alkane.
4. A supported polymerisation catalyst system according to claim 1 wherein the inert material is polyisobutene.
5. A supported polymerisation catalyst system according to claim 1 wherein the porous support is silica.
6. A supported polymerisation catalyst system according to claim 1 wherein the polymerisation catalyst is a transition metal compound.
7. A supported polymerisation catalyst system according to claim 6 wherein the transition metal compound is a metallocene.
8. A supported polymerisation catalyst system according to claim 7 wherein the metallocene has the formula
wherein:
R′ each occurrence is independently selected from hydrogen, hydrocarbyl, silyl, germyl, halo, cyano, and combinations thereof, said R′ having up to 20 nonhydrogen atoms, and optionally, two R′ groups (where R′ is not hydrogen, halo or cyano) together form a divalent derivative thereof connected to adjacent positions of the cyclopentadienyl ring to form a fused ring structure;
X is hydride or a moiety selected from the group consisting of halo, alkyl, aryl, aryloxy, alkoxy, alkoxyalkyl, amidoalkyl, siloxyalkyl etc. having up to 20 non-hydrogen atoms and neutral Lewis base ligands having up to 20 non-hydrogen atoms,
Y is —O—, —S—, —NR*—, or —PR*—,
M is hafnium, titanium or zirconium,
Z* is SIR* 2 , CR* 2 , SiR* 2 SIR* 2 , CR* 2 CR* 2 , CR*=CR*, CR* 2 SIR* 2 , or GeR* 2 , wherein:
R* each occurrence is independently hydrogen, or a member selected from hydrocarbyl, silyl, halogenated alkyl, halogenated aryl, and combinations thereof, said
R* having up to 10 non-hydrogen atoms, and optionally, two R* groups from Z* (when R* is not hydrogen), or an R* group from Z* and an R* group from Y form a ring system,
and n is 1 or 2 depending on the valence of M.
9. A supported polymerisation catalyst system according to claim 7 wherein the metallocene has the formula
wherein:
R′ each occurrence is independently selected from hydrogen, hydrocarbyl, silyl, germyl, halo, cyano, and combinations thereof, said R′ having up to 20 nonhydrogen atoms, and optionally, two R′ groups (where R′ is not hydrogen, halo or cyano) together form a divalent derivative thereof connected to adjacent positions of the cyclopentadienyl ring to form a fused ring structure;
X is a neutral η 4 bonded diene group having up to 30 non-hydrogen atoms, which forms a π-complex with M;
Y is —O—, —S—, —NR*—, or —PR*—,
M is titanium or zirconium in the +2 formal oxidation state;
Z* is SiR* 2 , CR* 2 , SiR* 2 SIR* 2 , CR* 2 CR* 2 , CR*═CR*, CR* 2 SIR* 2 , or GeR* 2 , wherein:
R* each occurrence is independently hydrogen, or a member selected from hydrocarbyl, silyl, halogenated alkyl, halogenated aryl, and combinations thereof, said
R* having up to 10 non-hydrogen atoms, and optionally, two R* groups from Z* (when R* is not hydrogen), or an R* group from Z* and an R* group from Y form a ring system.
10. A supported polymerisation catalyst system according to claim 1 wherein the cocatalyst has the formula
(L*−H) = d (A d− )
wherein
L* is a neutral Lewis base
(L*−H) + d is a Bronsted acid
A d− is a non-coordinating compatible anion having a charge of d − , and d is an integer from 1 to 3.
11. A supported polymerisation catalyst system according to claim 10 wherein the cocatalyst comprises a cation and an anion wherein the anion has at least one substituent comprising a moiety having an active hydrogen.
12. A supported polymerisation catalyst system comprising the combination of
(i) a porous support,
(ii) a polymerisation catalyst, and
(iii) a cocatalyst,
wherein an inert material and a polymerisable monomer are added to the porous support.
13. A supported polymerisation catalyst system according to claim 12 wherein the polymerisable monomer is 1-hexene.
14. A process for the polymerisation of olefin monomers selected from (a) ethylene, (b) propylene (c) mixtures of ethylene and propylene and (d) mixtures of (a), (b) or (c) with one or more other alpha-olefins, said process performed in the presence of a supported polymerisation catalyst system as claimed in claim 1 .
15. A process for the polymerisation of ethylene or the copolymerisation of ethylene and α-olefins having from 3 to 10 carbon atoms, said process performed under polymerisation conditions in the present of a polymerisation catalyst system as claimed in claim 1 .
16. A process according to claim 15 wherein the α-olefin is 1 -butene, 1-hexene, 4-methyl-1-pentene or 1-octene.
17. A process according to claim 14 performed in the gas phase.
18. A process according to claim 17 performed in a fluidised bed gas phase reactor.