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Title:
SUPPORTED OLEFIN POLYMERIZATION CATALYSTS
Document Type and Number:
WIPO Patent Application WO/2002/079276
Kind Code:
A2
Abstract:
A method for forming supported late transition metal olefin polymerization catalysts is described in which an al-ready formed transition metal complex, usually containing a reactive functional group, is placed on a support containing a complementary reactive functional group. Also described are novel polymerization catalyst components containing late transition metal complexes of neutral tridentate ligands.

Inventors:
PREISHUBER-PFLUEGL PETER (DE)
Application Number:
PCT/US2002/010044
Publication Date:
October 10, 2002
Filing Date:
March 28, 2002
Export Citation:
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Assignee:
DU PONT (US)
UNIV NORTH CAROLINA (US)
PREISHUBER-PFLUEGL PETER (DE)
International Classes:
A61N1/40; A61N2/02; C08F4/70; C08F110/02; (IPC1-7): C08F10/02; C08F10/00
Foreign References:
US6103658A2000-08-15
US6197715B12001-03-06
Other References:
PANCHENKO V N ET AL: "POLYMERIZATION OF ETHYLENE ON SUPPORTED CATALYSTS BASED ON ORGANIC CHELATE NICKEL COMPLEXES" POLYMER SCIENCE: SERIE A, INTERPERIODICA, US, vol. 37, no. 9, 1 September 1995 (1995-09-01), pages 867-873, XP000540700 ISSN: 0965-545X
Attorney, Agent or Firm:
Bowen Jr., Alanson G. (Legal Patent Records Center 4417 Lancaster Pik, Wilmington DE, US)
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Claims:
CLAIMS What is claimed is:
1. A process for the preparation of a supported olefin polymerization catalyst component, comprising the step of contacting: (a) a transition metal complex of a Group 610 transi tion metal (IUPAC notation), and a neutral bidentate or a neutral tridentate ligand, which ligand contains a first re active group, with (b) a solid support which has attached to it a compli mentary second reactive group, under conditions such that the first reactive group and com plimentary second reactive group interact to form an ionic or covalent bond.
2. The process of claim 1, wherein said first reactive group is hydroxyl, carboxyl, amino, carboxyl ester, alk oxysilane, thiol, siloxane, silanol, hydrosilane, aminosi lane, halosilane, alkyl groups bound to aluminum, zinc or magnesium, borane, sulfonate ester, epoxide, ketone, alde hyde, carboxylate salt, isocyanate, ammonium salt, phos phine, or sulfonate salt.
3. The process of claim 2, wherein said first reactive group is hydroxyl or amino.
4. The process of claim 3, wherein said complementary second reactive group is isocyanate, acyl halide, alkoxysi lane, siloxane, silanol, hydrosilane, aminosilane, halosi lane, an alkyl group bound to aluminum, zinc or magnesium, borane, phosphine, or alkyl halide.
5. The process of claim 1, wherein said support is an organic polymer, an inorganic oxide or a magnesium halide.
6. The process of claim 1, wherein said neutral biden tate ligand is wherein: R13 and R16 are each independently hydrocarbyl or substi tuted hydrocarbyl, provided that the atom bound to the imino nitrogen atom has at least two carbon atoms bound to it; and R14 and R15 are each independently hydrogen, hydrocarbyl, sub stituted hydrocarbyl or an inert functional group, or R14 and R15 taken together are hydrocarbylene or substituted hydro carbylene to form a carbocyclic ring.
7. The process of claim 6, wherein said transition metal is nickel.
8. The process of claim 1, wherein said neutral triden tate ligand is wherein: R, R2, R3, R4 and R5 are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl, or an inert functional group, provided that any two of R1, R2 and R3 vicinal to one another, taken together may form a ring; and R6 and R7 are aryl or substituted aryl.
9. The process of claim 8, wherein said transition metal is iron or cobalt.
10. A supported olefin polymerization catalyst compo nent, comprising a transition metal complex of a Group 610 transition metal and a neutral tridentate ligand, and a sup port material, whereby said transition metal complex is bound to said support material through an ionic or covalent bond between said neutral tridentate ligand and said sup port.
11. The supported olefin polymerization catalyst compo nent of claim 10, wherein said neutral tridentate ligand is wherein: R, R2, R3, R4 and R are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl, or an inert functional group, provided that any two of R1, R2 and R3 vicinal to one another, taken together may form a ring; and R6 and R7 are aryl or substituted aryl.
12. The supported olefin polymerization catalyst compo nent of claim 11 wherein said transition metal is iron or cobalt.
Description:
TITLE SUPPORTED OLEFIN POLYMERIZATION CATALYSTS FIELD OF THE INVENTION A method for forming supported late transition metal olefin polymerization catalysts is described in which an al- ready formed transition metal complex, usually containing a reactive functional group, is placed on a support containing a complementary reactive functional group.

FIELD OF THE INVENTION Olefin polymerization catalyst systems are an important commercial technology. In many instances these catalyst systems contain a transition metal complex which is essen- tial to their catalytic activity. In recent years, polym- erization catalysts containing late transition metals such as iron, cobalt, palladium and nickel have been developed, and in some instances these polymerization catalyst systems make unique polymers. It is well known in the art that po- lymerization catalysts containing transition metals are of- ten advantageously used when the transition metal (complex) is part of a supporting material such as a polymer or an in- organic compound such as silica, alumina, a magnesium hal- ide, etc. These supported catalysts are especially useful in so-called gas phase or liquid slurry polymerization proc- esses.

In a simple process for supporting a transition metal containing polymerization catalyst, a solution of the appro- priate transition metal compound is mixed with the desired support and the solvent is evaporated. In many such in- stances the transition metal containing polymerization cata- lyst may simply be coated (as paint is coated on a wall) onto the support and may be removed. In some instances, the support such as silica may be prereacted with another com- pound of the polymerization system such as an alkylaluminum

compound and then this support mixed with the transition metal containing polymerization catalyst.

Another less common way to affix the transition metal containing polymerization catalyst to a support is through a covalent bonded linkage which is attached to both the sup- port and the transition metal containing polymerization catalyst, see for instance EP-A-0953580 which describes the preparation of a heterogeneous catalyst containing metallo- cene-type catalysts. Metallocenes have anionic ligands.

US6030917 describes methods for making supported polym- erization catalysts containing late transition metals having neutral ligands attached to them. In the methods described therein, the ligand is attached to the support first and then ligand is coordinated with the desired transition metal.

WO00/56786 and WO00/56787 describe the preparation of supported transition metal polymerization catalysts in which the transition metal is complexed to an anionic ligand, but not to a neutral ligand.

W099/28352 describes the preparation of various sup- ported polymerization catalysts containing transition met- als. Some neutral ligands are used, but the metal is not complexed with the ligand until after the ligand is attached to the support.

US5955555 and W099/12981 describe the use of certain iron and cobalt complexes containing neutral tridentate lig- ands as olefin polymerization catalysts. Although supported catalysts are mentioned, no mention is made of having reac- tive groups on the neutral tridentate ligands.

All of the above-mentioned publications are incorpo- rated by reference herein for all purposes as if fully set forth.

SUMMARY OF THE INVENTION This invention concerns a process for the preparation of a supported olefin polymerization catalyst component, comprising the step of contacting: (a) a transition metal complex of a Group 6-10 transi- tion metal (IUPAC notation), and a neutral bidentate or a neutral tridentate ligand, which ligand contains a first re- active group, with (b) a solid support which has attached to it a compli- mentary second reactive group, under conditions such that the first reactive group and com- plimentary second reactive group interact to form an ionic or covalent bond.

This invention also concerns a supported olefin polym- erization catalyst component, comprising a transition metal complex of a Group 6-10 transition metal and a neutral tri- dentate ligand, and a support material, whereby said transi- tion metal complex is bound to said support material through an ionic or covalent bond between said neutral tridentate ligand and said support.

This invention still further concerns a process for the polymerization of one or more olefins, comprising the step of contacting said one or more olefins with an olefin polym- erization catalyst under polymerization conditions, whereby said olefin polymerization catalyst comprises the aforemen- tioned tridentate ligand based polymerization catalyst com- ponent, or a polymerization catalyst component obtained by the aforementioned process.

These and other features and advantages of the present invention will be more readily understood by those of ordi- nary skill in the art from a reading of the following de- tailed description. It is to be appreciated that certain features of the invention which are, for clarity, described

below in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any subcombination.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Herein, certain terms are used. Some of them are: A"hydrocarbyl group"is a univalent group containing only carbon and hydrogen. As examples of hydrocarbyls may be mentioned unsubstituted alkyls, cycloalkyls and aryls.

If not otherwise stated, it is preferred that hydrocarbyl groups herein contain 1 to about 30 carbon atoms.

By"substituted hydrocarbyl"herein is meant a hydro- carbyl group that contains one or more (types of) substitu- ents that do not substantially interfere with the operation of the polymerization catalyst system. Suitable substitu- ents in some polymerizations may include some or all of halo, ester, keto (oxo), amino, imino, carboxyl, phosphite, phosphonite, phosphine, phosphinite, thioether, amide, ni- trile, and ether. Preferred substituents when present are halo, ester, amino, imino, carboxyl, phosphite, phosphonite, phosphine, phosphinite, thioether, and amide. Which sub- stituents are useful in which polymerizations may in some cases be determined by reference to previously incorporated US5955555, as well as US5880241 (also incorporated by refer- ence herein for all purposes as if fully set forth). If not otherwise stated, it is preferred that substituted hydrocar- byl groups herein contain 1 to about 30 carbon atoms. In- cluded in the meaning of"substituted"are chains or rings containing one or more heteroatoms, such as nitrogen, oxygen and/or sulfur, and the free valence of the substituted hy- drocarbyl may be to the heteroatom. In a substituted hydro-

carbyl, all of the hydrogens may be substituted, as in tri- fluoromethyl.

By" (inert) functional group"herein is meant a group other than hydrocarbyl or substituted hydrocarbyl that is, other than participating in the ionic or covalent bond be- tween the ligand and support, inert under the process condi- tions to which the compound containing the group is sub- jected. The functional groups also do not substantially in- terfere with any process described herein that the compound in which they are present may take part in. Examples of functional groups include some halo groups (for example fluoro and some unactivated chloro) ether such as-OR22 wherein R22 is hydrocarbyl or substituted hydrocarbyl. In cases in which the functional group may be near a metal atom, the functional group should not coordinate to the metal atom more strongly than the groups in those compounds are shown as coordinating to the metal atom, that is they should not displace the desired coordinating group.

By an"activator","cocatalyst"or a"catalyst activa- tor"is meant a compound that reacts with a transition metal compound to form an activated catalyst species. This tran- sition metal compound may be added initially, or may be formed in situ, as by reaction of a transition metal com- pound with an oxidizing agent. A preferred catalyst activa- tor is an"alkyl aluminum compound", that is, a compound which has at least one alkyl group bound to an aluminum atom. Other groups such as, for example, alkoxide, hydride and halogen, may also be bound to aluminum atoms in the com- pound.

"Alkyl group"and"substituted alkyl group"have their usual meaning (see above for substituted under substituted hydrocarbyl). Unless otherwise stated, alkyl groups and

substituted alkyl groups preferably have 1 to about 30 car- bon atoms.

By"aryl"is meant a monovalent aromatic group in which the free valence is to the carbon atom of an aromatic ring.

An aryl may have one or more aromatic rings which may be fused, connected by single bonds or other groups.

By"substituted aryl"is meant a monovalent aromatic group substituted as set forth in the above definition of "substituted hydrocarbyl". Similar to an aryl, a substi- tuted aryl may have one or more aromatic rings which may be fused, connected by single bonds or other groups; however, when the substituted aryl has a heteroaromatic ring, the free valence in the substituted aryl group can be to a het- eroatom (such as nitrogen) of the heteroaromatic ring in- stead of a carbon.

By a"neutral"ligand is meant a ligand that electri- cally neutral, that is bears no charge. Another way of put- ting this is that the ligand is not ionic. However, the li- gand may contain a functional group that is an anion but, when the ligand is complexed with a transition metal, such functional group is not coordinated to the transition metal and thus is free to ionically or covalently bond to a sup- port.

By a"bidentate"ligand is meant a ligand that is capa- ble of being a bidentate ligand, that is it has two sites, often heteroatom sites, that can coordinate to a transition metal atom simultaneously. Preferably both sites do coordi- nate to the transition metal.

By a"tridentate"ligand is meant a ligand that is ca- pable of being a tridentate ligand, that is it has three sites, often heteroatom sites, that can coordinate to a transition metal atom simultaneously. Preferably all three sites do coordinate to the transition metal.

By a"first reactive group"is meant a group, usually a functional group which is reactive (see below), and whose presence does not substantially interfere with the function- ing of the transition metal complex as a component of an olefin polymerization catalyst system. Typically this group will be placed at a location in the transition metal complex which is somewhat remote from the transition metal atom it- self, so as to avoid potential interference in the catalytic function of the complex.

By a"complimentary second reactive group"is meant a reactive group which is part of the support, or is placed on the support, which usually (that is usually reacts in simi- lar situations) reacts under the process conditions of the contacting with the first reactive group to in effect con- nect, preferably covalently connect, the support and the transition metal complex.

By a"neutral tridentate ligand is bound to said sup- port through an ionic or covalent bond"is meant that the ligand is bound to the support through a group bound to the neutral tridentate ligand and not through a"bridging group" which includes the transition metal and/or any other ligand (other than the neutral tridentate ligand) bound to the transition metal.

When the transition metal complex and the support are mixed the second reactive group may not be present yet on the support, but another reagent may be added (either be- fore, simultaneously with or after the transition metal com- plex is contacted) which"reacts"with the support and forms the complimentary second reactive group on the support. The first reactive group of the transition metal complex may also be formed in a similar way, although it is preferred that it be formed before coming into contact with the sup- port.

The first reactive group may be any reactive group which is covalently bonded to the neutral bidentate or tri- dentate ligand. Reactive groups include, but are not lim- ited to, hydroxyl, carboxyl, amino, carboxyl ester, alk- oxysilane, thiol, siloxane, silanol, hydrosilane (silicon hydride), aminosilane, halosilane, alkyl groups bound to aluminum, zinc or magnesium, borane, sulfonate ester, epox- ide, ketone, aldehyde, carboxylate salt, isocyanate, ammo- nium salt, phosphine, and sulfonate salt. Preferred first reactive groups are hydroxyl, amino, carboxyl, carboxyl es- ter, alkoxysilane, halosilane, and hydroxyl and amino are especially preferred. Usually the neutral bidentate or tri- dentate ligand containing the first reactive group will be synthesized and then coordinated to the transition metal atom by reaction with an appropriate transition metal com- pound. Typical useful types of neutral bidentate and tri- dentate ligands will be found in previously incorporated US5880241, US5955555 and W09912981, as well as in US5932670, US6034259, US5714556, US6103658, US6174976, W09847934, W09840420, W09946302, W09946303, W09946304, W00006620, W00018776, W00020427, W00050470 and W00059914, all of which are also incorporated by reference herein for all purposes as if fully set forth. These references describe which transition metals are useful with these types of ligands, and also describe how to make the complexes of these ligands with appropriate transition metals, and reference may be had thereto for further details.

The complimentary second reactive group is a functional group that, under the contacting conditions (contacting of the transition metal compound and support), normally reacts with the first reactive group. Such pairs are well known in the art. For example, functional groups which are compli- mentary with a hydroxyl group include isocyanate, acyl hal-

ide, alkoxysilane, aminosilane, halosilane, alkyl groups bound to aluminum, zinc or magnesium, epoxide, carboxyl, carboxylic anhydride, and borane. Table I lists other first reactive groups and potential groups useful as complimentary second reactive groups. This list is not all inclusive for any first reactive group.

Table 1 First Reactive Group Second Reactive Group (s) carboxylic acid halide hydroxyl, amino carboxylic acid hydroxyl, amino, epoxide, isocyanate, alkyi groups bound to aluminum carboxylic acid anhydride hydroxyl, amino, alkyl bound to aluminum carboxyl ester alkyl groups bound to aluminum c ano alk I rou s bound to aluminum, hydroxyl sulfonyl halide hydroxyl, amino amino epoxide, isocyanate, carboxylic acid, carboxylic acid anhy- dride, carboxylic acid halide, alkyl halide, alkyl groups bound to aluminum, halosilane hydroxyl epoxide, isocyanate, carboxylic acid anhydride, carboxylic acid halide, alkyl groups bound to aluminum, alkyl groups bound to zinc, alkyl groups bound to magnesium, halosilane, alkoxysilane, siloxane, borane thiol epoxide, isocyanate, carboxylic acid anhydride, carboxylic acid halide, alkyl groups bound to aluminum, halosilane, alkoxysilane, siloxane, borane ketone alkyl groups bound to aluminum, amino aldehyde alkyl groups bound to aluminum, amino epoxide hydroxyl, isocyanate, carboxylic acid, carboxylic acid anhy- dride, carboxylic acid halide, alkyl groups bound to alumi- num, halosilane, alkoxysilane, siloxane, phosphine isocyanate carboxylic acid borane Hydroxyl alkoxysilane, halosilane, hydroxyl, amino siloxane silanol epoxide, isocyanate, carboxylic acid, carboxylic acid anhy- dride, carboxylic acid halide, alkyl groups bound to alumi- num, alkyl groups bound to zinc, halosilane, alkoxysilane, siloxane, borane phosphine alkyl halide, epoxide alkyl halide amino, phosphine borane Hydroxy carboxylate salt Ammonium salt, positive charged support sulfonatesalt Ammonium salt, positive charged support ammonium salt Carboxylate salt, sulfonate salt, negative charged clay min- erals

Preferred"pairs"of functional groups include: hy- droxyl and aluminum alkyl, hydroxyl and halosilane, hydroxyl and alkoxysilane, hydroxyl and epoxide, hydroxyl and carbox-

ylic acid anhydrides, amino and aluminum alkyl, amino and halosilane, amino and alkyl halides, aldehydes and aluminum alkyl, ketones and aluminum alkyl, esters and aluminum al- kyl ; especially preferred are hydroxyl and aluminum alkyl, amino and aluminum alkyl. Note that in principle in such "pairs", the first reactive group is interchangeable with the second reactive group. This interchangeability will be limited to some degree by the ability to synthesize the li- gand containing the first reactive group and then form the transition metal complex, as well as the ability to synthe- size a support containing any particular second reactive group.

The reactive pairs of first and second reactive groups would normally be expected under most circumstances to react with each other to form linkages between the moieties that two groups were originally bound to. These linkages may be covalent bonds or ionic"bonds". It is preferred that these first and second reactive groups be chosen so that covalent bonds would normally be thought to be formed by reaction of the first and second reactive groups. It is preferred also that the neutral bidentate or tridentate ligand is bound to the support through a group bound to the neutral bidentate or tridentate ligand and not through a"bridging group" which includes the transition metal and/or any other ligand (other than the neutral tridentate ligand) bound to the transition metal. This will normally be the case when the first reactive group is attached to the neutral bidentate or tridentate ligand.

Depending on what the supporting material is, the sec- ond functional group may"inherently"be part of the sup- port. For example, if the support is an organic polymer, a functional group which was part of one of the monomers used to prepare that polymer may be the second functional group.

An example of this would be a halo group which can react with an amino first reactive group. If the support is an inorganic material, for example silica based, a hydroxyl group which is a first reactive group may react with a sila- nol or a siloxane (particularly when the silica is highly dehydrated) to attach the ligand essentially as an alkoxysi- lane group onto the silica support.

As mentioned above the first and/or second reactive groups may be formed before, during or after the contacting of the metal complex and the support. For instance a silica support may be reacted with an alkylaluminum compound in such a manner so that not all of the alkyl groups bonded to aluminum are reacted. This is usually believed to attach alkylaluminum compounds to the silica surface. A transition metal complex having hydroxyl groups bonded to the ligand may then be added. Under these conditions hydroxyl groups normally react with (some of) the remaining alkylaluminum groups on the surface of the support. The procedure can also be run in"reverse", the transition metal complex re- acted with an alkylaluminum compound and then the silica support added. In a third procedure, the transition metal complex with a hydroxyl group, the silica and the alkylalu- minum compound may be contacted essentially simultaneously.

Silicon compounds such as dialkoxysilanes, dihalosilanes, diaminosilanes and silicon hydrides may be used in methods analogous to the use of alkylaluminum compounds. Other pro- cedures will be evident to the artisan, and may also be found in previously incorporated US6030917, W099/28352, WO00/56786, WO00/56787 and EP-A-0953580.

A preferred neutral bidentate ligand is

wherein: R13 and R16 are each independently hydrocarbyl or substi- tuted hydrocarbyl, provided that the atom bound to the imino nitrogen atom has at least two carbon atoms bound to it; and R14 and R15 are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or an inert functional group, or R14 and R15 taken together are hydrocarbylene or substituted hy- drocarbylene to form a carbocyclic ring.

As examples of when R14 and Rl5 are each independently a substituted hydrocarbyl may be mentioned when R is -A (Rl7) (Rl8) and R15 is-E (R19) (RZ°), wherein A and E are each independently nitrogen, oxygen, phosphorous or sulfur and Rl7 and Rl9are each independently hydrocarbyl, or substituted hydrocarbyl or taken together form a ring, and R18 and R20 are each independently hydrogen, hydrocarbyl, or substituted hy- drocarbyl, provided that when A is oxygen or sulfur R18 is not present, and when E is oxygen or sulfur R 20 is not pres- ent.

In one preferred embodiment of (I), at least one of R14 and Rl5 is an inert functional group constituting the first reactive group, or a substituted hydrocarbyl containing such an inert functional group. More preferably, at least one of R14 and Rl5 is a substituted hydrocarbyl containing such an inert functional group.

In another preferred embodiment of (I), at least one of R13 and R16 is a substituted hydrocarbyl containing an inert functional group constituting the first reactive group. In

a particularly preferred embodiment, at least one of R13 and R16 is a substituted aryl which is substituted with such an inert functional group at a position remote from the imino nitrogen (e. g., the 4-position), or a substituted hydrocar- byl (e. g., substituted alkyl) containing such an inert func- tional group.

A preferred neutral tridentate is wherein: R, R2, R3, R4 and Rs are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl, or an inert functional group, provided that any two of Rl, R2 and R3 vicinal to one another, taken together may form a ring; and R6 and R7are aryl or substituted aryl.

In one preferred embodiment of (II), at least one of Rl, R2, R3, R4 and R is an inert functional group constituting the first reactive group, or a substituted hydrocarbyl con- taining such an inert functional group. More preferably, at least one of Rl, R2, R3, R4 and R5 (and particularly at least one of R1, R2 and R3) is a substituted hydrocarbyl containing such an inert functional group.

In another preferred embodiment of (II), at least one of R6 and R7 is a substituted aryl containing an inert func- tional group constituting the first reactive group. In a particularly preferred embodiment, at least one of R6 and R7 is a substituted aryl which is substituted with such an in- ert functional group at a position remote from the imino ni- trogen (e. g., the 4-position), or a substituted hydrocarbyl

(e. g., substituted alkyl) containing such an inert func- tional group.

In other preferred forms of (I) and (II) it is pre- ferred that R6, R7, Rl3 and Rl5 are each independently dior- tho (substituted aryl), that is have aryl or substituted aryl groups in both ortho positions to the carbon atom bound to the imino nitrogen atom, and it is even more preferred that R6, R7, R13 and R16 are 2,6-diaryl (or substituted di- aryl) phenyl groups. Preferred substitutents R6, R7, Rl3 and R16 may be found in analogous complexes [applicable to both (I) and (II) herein, no matter what type of complex they are found in these references] in W00050471, and W01042257, which is hereby included by reference. Therefore useful groups for R6, R7, R13 and R16 include groups such as 2,6- diphenylphenyl, 2,6-bis (2-methylphenyl) phenyl and 2,6-bis (4- t-butylphenyl) phenyl. In addition diortho substitution, other groups may also be substituted in the R6, R7, R13 and R16 moieties, including the first reactive group or a group containing the first reactive group, as described herein.

Preferred transition metals are in Groups 8-10. Pre- ferred specific transition metals are Fe, Co, Pd, Ni, Mn and Ru, and more preferred metals are Fe, Co, Pd and Ni. With (I), Ni and Pd are preferred metals, and Ni is especially preferred, while with (II) Fe and Co are preferred and Fe is especially preferred.

A preferred olefin for polymerization (including oli- gomerization) with the present supported catalysts is ethyl- ene, or a combination of ethylene and an olefin of the for- mula R8CH=CH2 wherein R8 is n-alkyl, the latter to give an ethylene copolymer. Another preferred combination of ole- fins is ethylene with an olefin containing a polar group, such as methyl acrylate. Which catalysts can be used to po- lymerize which olefin (s) will be found in previously incor-

porated US5880241, US5932670, US5955555, US6034259, US5714556, US6103658, US6174976, W098/47934, W098/40420, <BR> <BR> W099/12981, W099/46302, W099/46303, W099/46304, WO00/06620, WO00/18776, WO00/20427, WO00/50470 and WO00/59914, and other references known to the artisan.

Also the polymerization conditions for the present sup- ported catalysts are the same as reported previously for those of these classes already known, as disclosed in the aforementioned incorporated references as well as US5852145, US6063881, US6114483, US6150482, W097/48735, W098/56832, W099/50318, W099/62963, W099/62967, W00010945, WO00/22007 and WO00/50475, all of which are also incorporated by refer- ence herein for all purposes as if fully set forth. These references also describe the use of olefin polymerization catalysts containing these types of transition metal cata- lysts in various ways, such as the types (gas phase, slurry, etc.) of polymerization processes that may be used, modifi- ers (hydrogen for example) that may be added, and the use of more than one polymerization catalyst to produce various kinds of polymer products. All of these processes are equally applicable to the present supported catalysts. For example, more than one transition metal complex may be on the catalyst support, one or both them being attached through first reactive groups.

Preferred supports are organic polymers, especially those containing a complimentary second reactive group as part of their polymer"structure", inorganic oxides such as silica, silica gel, or alumina, a magnesium halide, titania, and clay minerals. Especially preferred supports include organic polymer, especially those containing a complimentary second reactive group as part of their polymer"structure", silica, alumina, and alumina silicates. Loadings of the transition metal complex onto the supports may the same as

those conventionally used with other similar supported cata- lysts.

The supported olefin polymerization catalyst component, comprising, a Group 6-10 transition metal complex containing a neutral tridentate ligand complexed to said transition metal, and a support material, provided that said neutral tridentate ligand is bound to said support through an ionic or covalent bond, may be made by the methods described herein, that is the fully formed complex (including transi- tion metal) may be contacted with the support, or the ligand (without transition metal) can be contacted with the support and then the ligand complexed with the transition metal.

In the Examples, the following abbreviations are used: dme-1, 2-dimethoxyethane Me-methyl MMAO-methyl aluminoxane modified with isobutyl groups Rt-room temperature THF-tetrahydrofuran TLC-thin layer chromatography The following convention is used for describing some of the complexes: (i) DAB (ii), wherein DAB stands for a- diimine; (i) are the groups attached to the nitrogen (see R13 and R16 in (I)); and (ii) are the group (s) on the two carbon atoms of the a-diimine (see R14 and Rl5 in (I)). More de- tails on this nomenclature will be found in previously in- corporated US6034259.

Example 1 Synthesis of 3- (4-Amino-3, 5-dimethylphenyl) propan-1-ol

Palladium acetate (68 mg) and 720 mg of tris-o- tolylphosphine were mixed in a Schlenk tube under a nitrogen atmosphere. After 15 ml of triethylamine, 6 g of 4-bromo- 2,6-dimethylaniline and 3.2 g of methyl acrylate had been added, the tube was heated to 100°C in an oil bath and kept there for 6 h. The mixture was added to water and extracted 3 times with ethyl ether. After drying in vacuum 6.2 g of a yellow solid was obtained. The solid was dissolved in THF and 3.5 g of lithium aluminum hydride was added. After 6 h the reaction was poured into water and purified by column chromatography (silica, hexane: ethyl acetate 2: 1). A mix- ture of 3- (4-amino-3, 5-dimethyl-phenyl-propan-l-ol and 3- (4- amino-3,5-dimethylphenyl) propan-1-ol (3.5 g) was obtained.

The mixture was dissolved in ethyl acetate and 50 mg of pal- ladium (10 wt%) on carbon was added. Hydrogen was bubbled through the solution for one h. After removing the palla- dium catalyst and the solvent, 3.1 g of 3- (4-amino-3, 5- dimethyl-phenyl)-prop-2-en-1-ol was obtained.'H-NMR (200MHz, CDC13) : 6.77 (s, 2H), 3.64 (t, 2H), 3.47 (b s, 2H), 2.54 (t, 2H), 2.15 (s, 6H), 1.82 ppm (m, 2H).

Example 2 Synthesis of (2,6-Me2-4- (3-hydroxypropyl) Ph) 2DABAn 3- (4-Amino-3, 5-dimethylphenyl) propan-1-ol (2.9 g) and 1.33 g acenapthoquinone were solved in 60 ml of toluene.

After 0.1 ml of sulfuric acid had been added, the solution was refluxed and the water produced was removed by using a Dean-Stark trap. The red product was purified by column chromatography (silica, solvent ethyl acetate: hexane 3: 1).

Yield: 2.2 g of diimine. 1H-NMR (200 MHz, CDC13) : 7.86 (d, 2H), 7.37 (t, 2H), 6.97 (s, 4H), 6.69 (d, 2H), 3.74 (quart., 4H), 2.72 (t, 4H), 2.13 (s, 8H), 1.97 ppm (t, 4H) Example 3 Synthesis of (2,6-Me2-4- (3-hydroxypropyl) Ph) 2DABAnNiBr2 (2,6-Me2-4- (3-hydroxypropyl) Ph) 2DABAn (1785 mg) and 993 mg of NiBr2 dme were stirred in 30 ml of CH2Cl2 for 16 h. Af- ter removal of the solvent, the brown powder was washed 3 times with diethyl ether. Yield: 2.5 g of brown powder.

Example 4 Synthesis of Support, Si02/Me3Al Silica (Grace XPO 2402), 8 g, was mixed with 40 ml of dry toluene and 12 ml of a 2M Me3Al in hexane solution (Al- drich) was added. After 2 h the silica was washed 3 times with toluene and once with pentane. Afterwards the material was dried in vacuum at 25°C.

Example 5 Synthesis of Support, Si02/Me2AlCl Silica (Grace XPO 2402), 6 g, was mixed with 30 ml of dry toluene and 15 ml of a 1M Me2AlCl solution in hexane (Al- drich) was added. After 2 h the silica was washed 3 times with toluene, once with pentane and then dried in vacuum.

Example 6 Supporting of (2,6-Me2-4- (3-hydroxypropyl) Ph) 2DABAnNiBr2 On Si02/Me3Al Four hundred mg of Si02/Me3Al from Example 4 was mixed with a solution of 56.4 mg (2,6-Me2-4- (3- hydroxypropyl) Ph) 2DABAnNiBr2 (from Example 3) in 10 ml CH2C12.

After one h the clear CH2C12 phase was subjected to a vacuum, and the brown solid remaining was washed once with CH2C12.

Example 7 Supporting of (2,6-Me2-4- (3-hydroxypropyl) Ph) 2DABAnNiBr2 On Si02/Me3Al One hundred mg of SiO2/Me3Al from Example 4 were mixed with a solution of 58. 7 mg (2,6-Me2-4- (3- hydroxypropyl) Ph) 2DABAnNiBr2 (from Example 3) in 12 ml CH2Cl2.

After one h the colored CH2C12 phase was filtered off and the brown solid was washed once with CH2Cl2.

Example 8 Supporting of (2,6-Me2-4- (3-hydroxypropyl) Ph) 2DABAnNiBr2 On Si02/Me2AlCl Two hundred mg of Si02/Me2AlCl from Example 5 was mixed with a solution of 24 mg (2,6-Me2-4- (3- hydroxypropyl) Ph) 2DABAnNiBr2 (from Example 3) in 60 ml CH2C12.

After 2 h the slightly yellow solution was decanted and the remaining yellow solid dried in vacuum after washing 2 times with CH2C12.

Example 9 Polymerization of Ethylene with Catalyst of Example 6 One hundred ml pentane and 1.2 ml of 0.91 M solution of ethyl aluminum sesquichloride in toluene were pumped into a 300 ml Parr@ autoclave. The catalyst synthesized (6.5 mg) in Example 6 was added and the reactor was heated to 60°C and pressurized with 1.03 MPa of ethylene. After 2 h the polym-

erization was quenched by addition of methanol. White poly- ethylene particles (27.4 g) were obtained.

Example 10 Polymerization of Ethylene with Catalyst of Example 6 One hundred ml pentane, 0.1 ml of 0.91M ethyl aluminum sesquichloride in toluene, and 6.9 mg of the catalyst syn- thesized in Example 6 were combined in a 300 ml autoclave.

After 2 h at 60°C and 1.03 MPa ethylene, 28.1 g of PE was ob- tained.

Example 11 Polymerization of Ethylene with Catalyst of Example 7 One Hundred ml pentane, 1.0 ml of 0.91M ethyl aluminum sesquichloride in toluene, and 3.7 mg of the catalyst syn- thesized in Example 7 were combined in a 300 ml autoclave.

After 2 h at 60°C and 1.03 MPa ethylene, 38.2 g of polyethyl- ene was obtained.

Example 12 Polymerization of Ethylene with Catalyst of Example 8 One hundred ml pentane, 1.7 ml of a 1M Me2AlCl solution in hexane, and 40.5 mg of the catalyst synthesized in Exam- ple 8 were combined in a 300 ml autoclave. After 30 min at 50°C and 1.10 MPa ethylene, 21 g of polyethylene was ob- tained.

Example 13 Synthesis of 2,6-Bis- [l- (4-hydroxy-2- methylphenylimino) ethyl] pyridine 4-Amino-m-cresol (450 mg) and 300 mg 2,6- diacetylpyridine were dissolved in 20 ml methanol. Four drops of formic acid were added and the solution was stirred for 2 d. The yellow solid was washed with cold methanol.

Yield: 600 mg. 1H-NMR (200 MHz, CDC13) : 8.35 (d, 2H), 7.85 (t, 1H), 6.53-6.74 (6 H), 4.50 (s, 2H), 2.32 (s, 6H), 2.09 ppm (s, 6H)

Example 14 Synthesis of 2,6-Bis- [l- (4-hydroxy-2- methylphenylimino) ethyl] pyridine iron (II) chloride 2,6-Bis- [l- (4-hydroxy-2- methylphenylimino) ethyl] pyridine (73 mg) from Example 13 and 38 mg of FeCl2 4H2O were stirred in 10 ml THF for 16 h. After removal of the solvent by cannula transfer, the black powder was washed 3 times with THF. Yield 90 mg.

Example 15 Supporting of 2,6-bis- [l- (4-hydroxy-2- methylphenylimino) ethyl] pyridine Iron (II) Chloride On S iO2/Me3Al One hundred mg of SiO2/Me3Al from Example 4 was mixed with a solution of 10.5 mg 2,6-bis- [l- (4-hydroxy-2- methylphenylimino) ethyl] pyridine iron (II) chloride in 10 ml toluene. After 4 h the toluene phase was decanted and the black solid was washed once with toluene.

Example 16 Polymerization of Ethylene with Catalyst of Example 15 One hundred ml pentane and 1 ml MMAO solution in tolu- ene (7 wt% Al) were pumped in a 300 ml Parr@ autoclave.

Catalyst (15.9 mg) synthesized in Example 15 was added and the reactor was heated to 60°C and pressurized with 1.03 MPa of ethylene. After 60 min the polymerization was quenched by addition of water. The particles insoluble in pentane at 25°C were filtered off (6.1 g). The pentane phase was sepa- rated from the water in a separatory funnel. The pentane was distilled from the pentane phase (head temperature 38°C), and 6.2 g of an oil was obtained which turned solid on cool- ing to 20°C. The solid insoluble in pentane had a melting point of 80-110°C, while the materiel in the pentane phase was analyzed by 1H NMR and shown to be predominantly a- olefins with an average chain length of 12 carbon atoms.

Example 18 Synthesis of 2,6-bis- [l- (2, 6-dimethyl-4- (3- hydroxypropyl) phenylimino) ethyl] pyridine 3- (4-Amino-3, 5-dimethylphenyl) propan-1-ol (2.5 g) was synthesized following the method described in Example 1.

Two g of it and 0.9 g 2,6-diacetylpyridine were dissolved in 3 ml methanol. Two drops of formic acid were added and the solution was refluxed for 40 h. The crude product was puri- fied by column chromatography (silica, solvent ethyl ace- tate: hexane 1: 1). Yield 1.5 g of yellow powder. 1H-NMR (200 MHz, CDC13): 8.46 (d, 2H), 7.93 (t, 1H), 6.92 (s, 4H), 3.65 (t, 4H), 2.63 (t, 4H), 2.22 (s, 6H), 2.01 (s, 12H), 1.86 ppm (quin., 4H) Example 19 Synthesis of 2,6-bis- [l- (2, 6-dimethyl-4- (3- hydroxypropyl) phenylimino) ethyl] pyridine Iron (II) Chloride Five hundred mg of 2,6-bis- [l- (2, 6-dimethyl-4- (3- hydroxypropyl) phenylimino) ethyl] pyridine and 190 mg of FeCl2'4H20 were stirred in 7 ml THF for 80 min. After fil- tration the remaining purple powder was washed 2 times with THF and once with diethyl ether. Yield 600 mg.

Example 20 Supporting of 2,6-bis- [l- (2, 6-dimethyl-4- (3- hydroxypropyl) phenylimino) ethyl] pyridine Iron (II) Chloride on Si02/Me3Al Three hundred mg of SiO2/Me3Al from Example 4 was mixed with a solution of 38.5 mg 2,6-bis- [l- (2, 6-dimethyl-4- (3- hydroxypropyl) phenylimino) ethyl] pyridine iron (II) chloride in 10 ml CH2Cl2. After 60 min the clear CH2Cl2 phase was de- canted, and the green solid remaining was washed once with CH2Clz.

Example 21 Polymerization of Ethylene with Catalyst of Example 20 One hundred ml pentane, 1.0 ml MMAO solution in toluene (7 wt% Al) and 0.3 ml of trimethylaluminum (2 M solution in hexane) were pumped into a 300 ml Parr@ autoclave. The het- erogeneous catalyst synthesized in Example 20 (8.0 mg) was added and the suspension was stirred for 5 min at 25 °C.

Then the reactor was heated to 80°C and pressurized with 2.75 MPa of ethylene. After 120 min the polymerization was quenched by addition of methanol. White polyethylene parti- cles (51.9 g) were obtained.

Example 22 Synthesis of (4- (4-Amino-3, 5-Me2-benzyl)-2,6-Me2-Ph) 2DABAn Three g of 4,4'-methylenebis (2,6-dimethylaniline) (from Aldrich) and 0.54 g acenaphthoquinone were dissolved in 50 ml toluene. Four drops of sulfuric acid were added and the solution was refluxed for 14 h and the water produced was removed continuously by using a Dean-Stark trap. The crude product was purified by column chromatography (silica, sol- vent ethyl acetate: hexane 1: 1). Yield 1.2 g of red powder.

1H-NMR (200 MHz, CD2Cl2) : 7.89 (d, 2H), 7.37 (t, 2H), 7.01 (s, 4H), 6.87 (s, 4H), 6.74 (s, 2H), 3.84 (s, 4H), 3.53 (s, 4H), 2.19 (s, 12H), 2.06 ppm (s, 12H) Example 23 Synthesis of (4- (4-Amino-3, 5-Me2-benzyl)-2, 6-Me2- Ph) 2DABAnNiBr2 Sixty mg of (4- (4-amino-3, 5-Me2-benzyl)-2,6-Me2- Ph) 2DABAn and 28 mg of NiBr2'dme were stirred in 5 ml CH2Cl2 for 14 h. After the solvent had been removed via vacuum, the brown product was washed 2 times with diethyl ether.

Yield 70 mg of brown powder.

Example 24 Supporting of (4- (4-Amino-3, 5-Me2-benzyl)-2,6-Me2- Ph) 2DABAnNiBr2 on Si02/Me3Al One hundred mg of SiO2/Me3Al from Example 4 was mixed with a solution of 17.5 mg (4- (4-amino-3, 5-Me2-benzyl)-2,6- Me2-Ph) 2DABAnNiBr2 in 2 ml CH2C12. After 60 min the CH2C12 phase was subjected to vacuum, and the brown solid remaining was washed three times with CH2C12.

Example 25 Polymerization of Ethylene with Catalyst of Example 24 One hundred ml pentane, 1.0 ml of 0.91M solution of ethyl aluminum sesquichloride in toluene were pumped into a 300 ml Parr (E) autoclave. The catalyst synthesized in Example 24 (11.9 mg) was added and the reactor was heated to 60°C and pressurized with 1.03 MPa of ethylene. After 120 min the polymerization was quenched by addition of methanol. White polyethylene particles (38.7 g) were obtained.

Example 26 Synthesis of 2,6-Bis- [l- (4-amino-2,3,5,6-tetramethyl- phenylimino) ethyl] pyridine Eight hundred mg of 2,3,4,5-tetramethyl-1,4- phenylenediamine (from Aldrich) and 200 mg 2,6- diacetylpyridine were dissolved in 6 ml methanol. Two drops of formic acid were added and the solution was stirred for 16 h. Yellow crystals precipitated and were washed 2 times with cold methanol. Five hundred mg of yellow powder was obtained. 1H-NMR (200 MHz, CDC13): 8.44 (d, 2H), 7.91 (t, 1H), 3.45 (s, 4H), 2.15 (s, 6H), 2.13 (s, 12H), 1.94 ppm (s, 12H).

Example 27 Synthesis of 2,6-Bis- [l- (4-amino-2,3,5,6-tetramethyl- phenylimino) ethyl] pyridine Iron (II) Chloride 2,6-Bis- [l- (4-amino-2,3,5,6-tetramethyl- phenylimino) ethyl] pyridine (240 mg) and 95 mg of FeCl4HO were stirred in 5 ml THF for 60 min. After filtration the remaining gray powder was washed 3 times with THF and once with diethyl ether. Yield 220 mg.

Example 28 Supporting of 2,6-Bis- [l- (4-amino-2,3,5,6-tetramethyl- phenylimino) ethyl] pyridine Iron (II) Chloride on SiO2/Me3Al One hundred mg of Si02/Me3Al from Example 4 was mixed with a solution of 11.6 mg 2,6-bis- [l- (4-amino-2,3,5,6- tetramethyl-phenylimino) ethyl] pyridine iron (II) chloride in 25 ml CH2Clz. After 2 h the CH2C12 phase was decanted, and the black solid remaining was washed twice with CH2C12.

Example 29 Polymerization of Ethylene with Catalyst of Example 28 One hundred ml pentane and 1.5 ml MMAO solution in toluene (7 wt% Al) were pumped into a 300 ml Parr@ auto- clave. The catalyst synthesized in Example 28 (13.6 mg) was added and the reactor was heated to 60°C and pressurized with 2.75 MPa of ethylene. After 30 min the polymerization was quenched by addition of methanol. White polyethylene parti- cles (17.1 g) were obtained.

Example 30 Synthesis of 2- (4-amino-3, 5-dibromo) ethanol In a 1 L round bottom flask capped with a rubber sep- tum, 2- (4-aminophenyl) ethanol (15g, 109.3 mmol) was dis- solved in 450 mL glacial acetic acid. Bromine (12.4 mL, 242 mmol) was added drop-wise with a syringe at RT within 20 min. After stirring for 30 additional min at RT, the reac- tion was poured into 2 L of ice water. The resulting solid

was filtered in a Buchner filter and washed 5 times with 300 mL of ice water. The dibromide thus obtained was mostly in the acetate form. Yield 34 g (92.3 %). 1H-NMR (300MHz, CDC13) 7.21 (s, arom, 2H), 4.42 (br s, NH2, 2H) 4.14 (t, CH2-O, 2H), 2.75 (t, CH2-Ph, 2H), 1.95 (s, CH3-COOR, 3H).

Hydrolysis of the acetate was achieved by dissolving the crude dibromide (20g) in MeOH (150mL), adding K2CO3 (20g), 10 mL of H20 and stirring for 1 h at RT. The solution was then filtered and MeOH removed on a rotavap. The dibromide was then dissolved in diethyl ether (150mL) and washed with water (150mL) to remove residual contaminants. The water phase was extracted with diethyl ether. Both ether phases were combined and solvent removed (rotavap). A beige solid was obtained. Yield 12.8g (73.1%). 1H-NMR (300MHz, CDC13) 7.21 (s, arom, 2H), 4.42 (br s, NH2, 2H) 3.77 (t, CH2-O, 2H), 2.69 (t, CH2-Ph, 2H), 1.58 (br s, OH, 1H).

Example 31 Synthesis of 2- (4-amino-3, 5-diphenyl) ethanol 2- (4-Amino-3, 5-dibromo) ethanol (12.2g, 41.4 mmol), tetrakis (triphenylphosphine) palladium (5.6 g, 5.0 mmol), phenylboronic acid (15.6g, 127.9 mmol) and Na2CO3 (26.4g, 248.7 mmol) were dissolved in a degassed mixture of 350mL toluene, 75mL ethanol and 125mL of water, and refluxed under argon for 72h.. After cooling under argon, the water phase was extracted with diethyl ether and combined with the or- ganic phase. The crude product was purified by column chro- matography (silica gel/CHC13) under inert atmosphere. A first chromatographic column (W=45mm, L=100mm) was used to do a coarse separation and a second column (w=45mm, L=210mm) separated the desired ortho diphenyl substituted amine as the second main fraction (orange band). Column chromatogra- phy was followed by TLC. The ortho diphenyl substituted amine presented a characteristic blue spot under the W

lamp. After removing the solvent, 6.9g of a yellow solid were obtained (57.2%). 1H-NMR (300MHz, CDC13) 7.3-7.5 (m, arom, 10H), 6.98 (s, arom, 2H), 3.84 (t, CHz-O, 2H), 2.82 (t, CH2-Ph,2H).

Example 32 Synthesis of 2,3-Butanedione bis (2,6-diphenyl-4- hydroxyethylphenylimine) In a 1 L closed round bottom flask 2.2 equiv of 2- (4- amino-3,5-diphenyl) ethanol (3g, 10.4 mmol) were dissolved in benzene and a catalytic amount of p-toluenesulfonic acid monohydrate was added (110 mg, 0.58 mmol). Then 1 equiv of 2,3-butanedione (0.41 mL, 4.69 mmol) was added dropwise by syringe with stirring. After that, the flask was connected to a Dean Stark trap and a reflux condenser. After reflux- ing the mixture for 48 h, the solvent was removed. The crude product was purified in a short chromatographic column (silica, W=45mm, L=100mm). The diimine eluted as the second orange band, after elution of the unreacted amine, and after changing solvent mixture from CHCl3/EtOAc (5: 1) to CHC13/EtOAc (2: 1). Solvent was removed and the diimine was further purified by dissolving in warm methylene chloride and adding pentane. A bright yellow solid precipitated upon storage at-30°C overnight. Yield l. Og (33.9%). 1H-NMR (300MHz, CDC13) 7.08-7.25 (m, arom, 24H), 3.86 (t, CH2-O, 4H), 2.87 (t, CH2-Ph, 4H), 1.38 (s, CH3-C=N, 6H). Anal..

Calcd for C44H4oN202 : C, 84.04; H, 6.41; N, 4.46; O, 5.09 Found: C, 83.02; H, 6.41; N, 4.31; O, 5.12 Example 33 Synthesis of 2,3-Butanedione bis (2,6-diphenyl-4- hydroxyethylphenylimine) NiBr2 2,3-Butanedione-bis (2,6-diphenyl-4- hydroxyethylphenylimimine) (448mg, 0.713 mmol) and NiBr2 (dme) (200mg, 0.648 mmol) were stirred in 10 mL of dry CH2C12 for

18 h under argon. After removing the solvent under vacuum, the brown powder was washed 5 times with 15 mL of dry di- ethyl ether and cannula filtered. Yield 500 mg (91.1%).

Anal.. Calcd for C44H40N202NiBr2 : C, 62.37; H, 4.76; N, 3.31; O, 3.78 Found: C, 62.27; H, 4.86; N, 3.22; O, 4.04 Example 34 Preparation of support SiO2/Me3Al Silica (8g) was gently mixed with 40 mL of dry toluene and 12 mL of a 2M Me3Al hexane solution. For 2 h the reac- tion mixture was gently shaken several times, so as to avoid silica fragmentation. The treated silica was finally washed 3 times with toluene (40 mL) and once with pentane (40mL).

The material was dried under vacuum at 25°C.

Example 35 Supporting 2,3-Butanedione bis (2,6-diphenyl-4- hydroxyethylphenylimine) NiBr2 on Si02/Me3Al 2,3-Butanedione-bis (2,6-diphenyl-4- hydroxyethylphenylimine) NiBr2 (100 mg, from Example 33) was stirred for 15 minutes in 25 mL CH2C12. SiO2/Me3Al (600 mg, from Example 34) was added and gently mixed with the cata- lyst precursor. Almost instantaneously all catalyst precur- sor was trapped on the silica and the solution became clear.

The reaction was allowed to proceed for 1 h, after which the CH2Cl2phase was removed under vacuum and the brown solid was washed once with 15 mL of CH2C12. After cannula filtering, the brown solid was dried under vacuum.