WO2011085951A1

WO2011085951A1 - Oligomerization of olefins

Info

Publication number: WO2011085951A1
Application number: PCT/EP2011/000050
Authority: WO
Inventors: Katrin Schuhen; Reynald Chevalier; Sandro Gambarotta; Sebastiano Licciulli; Indira Thapa; Robbert Duchateau
Original assignee: Basell Polyolefine Gmbh; University Of Ottawa
Priority date: 2010-01-15
Filing date: 2011-01-08
Publication date: 2011-07-21
Also published as: WO2011085951A8

Abstract

The invention deals with oligomerization, especially tetramerization of olefins by use of a catalyst system comprising an organometalliccomplex of an element of group 3 to 10 of the Periodic Table of the Elements and a didendate nitogen comprising ligand.

Description

Oligomerization of Olefins Field of the Invention

The present invention relates to oligomerization of olefins, including oligomerization process, catalyst system for the oligomerization, a complex for the use in a catalyst system for the

oligomerization of olefins and a precursor of that complex. More particularly, the invention relates to a tetramerization process, a catalyst system for tetramerization of olefins and a complex for use in a catalyst system for tetramerization of olefins and the precursor of that complex. Background of the invention

Oligomers, and especially a-olefins, are used in polymerization processes often as monomers or comonomers to prepare polyolefins having interesting properties. Unfortunately, very few efficient processes are known which selectively produce a specifically desired oligomer. Conventional ethylene oligomerization technologies produce a range of olefins following either a Schulz-Flory or Poisson product distribution. By definition, these mathematical distributions limit the mass % of the dimer, trimer or tetramer that can be formed and make a distribution of products.

In US patents 3,676,523 and 3,635,937, the so-called SHOP process is disclosed which today is used for the synthesis of a statistical mixture of a-olefins, which can be fractioned for being marketed for a range of commercial applications. In these patents catalyst systems comprising Ni complexes comprising chelating ligands, e.g. 2-diphenyl phosphino benzoic acid, are reported.

But there also have been developed processes for producing selectively trimers as e.g. disclosed in US 2002/0035029 A1 , wherein pyrrazolyl chromium complexes are disclosed as precatalysts. Further examples are WO 2002/041 19 A1 disclosing a catalyst for trimerization of ethylene which comprises a source of chromium, molybdenum and tungsten and a ligand containing at least one phosphorous, arsenic or antimony atom bound to at least one heterohydrocarbyl group. Further examples are disclosed in US 5,811 ,618 A1 , WO 03/004158 A2, WO 03/053890 A1 , WO 04/056479 A1.

WO 2009/006979 A2 also discloses a catalyst system comprising a ligand of the general structure R₁R2P-N(R₃)-P(R4)-N(R₅)-H or R₁R₂P-N(R₃)-P(R₄)-N(R₅)-PR6R7.

In WO 2004/056478 A1 and WO 2004/056479 A1 a process for preparing 1-octene as the major component is disclosed, wherein a complex comprises a ligand having a phosphor-nitrogen- phosphor basic structure. A discussion of the catalytic process is described in J. Am. Chem. Soc, 2004, 126 (45), 14712-14713 and J. Am. Chem. Soc, 2005, 127 (30), 10723-10730. Catalysts having similar basic structures are also disclosed in Organometallics 2006, 25 (3), 715-718 and Organometallics 2007, 26 (10), 2782-2787. The cocatalyst influence on one of these complexes has been examined in Organometallics 2007, 26(10), 2561-2569.

Recently, in WO 2009/006979 A1 a process for di-, tri- and tetramerization of ethylene has been published, wherein also a catalyst is used which comprises chromium complexes with a ligand having a phosphor-nitrogen-phosphor structure. In the examples good yields of di- and trimers are disclosed.

Summary of the Invention

In view of the prior art there still exists a need for providing compositions and processes for preparing lower oligomers and especially preparing selectively one kind of a low oligomer. A special interest exists in a process for preparing tetramers.

It is an object of the present invention to find compounds which, when used as catalyst constituents, are able to produce oligomers additionally to polymers and especially to selectively produce one kind of low oligomer.

We have found that this object is achieved by an organometallic transition metal compound of the formula (I)

wherein

L¹ and L² are each independently selected from carbon, silicon, germanium, phosphorous, and arsenic,

R⁰¹ together with R⁰² and the atoms connecting them may form an aromatic or aliphatic five-, six- or seven-mem bered nitrogen heterocycle or R⁰¹ and R⁰² are identical or different and are each, independently of one another, Ci-C₅₀-alkyl, C2-C₅₀-alkenyl, C₅-C₅₀-aryl, Ci-C₅₀-alkoxy, or C₅-C₅₀- aryloxy, wherein the organic radicals R⁰ and R⁰² may also be substituted by halogens, CrCso-alkyl, C₂-C₅₀-alkenyl, C₅-C₅o-aryl, d-Cso-alkoxy, C₅-C₅₀-aryloxy or SiR⁰⁷ ₃, R⁰¹ and R⁰² and their substituents may also contain one or more heteroatoms selected from N, P, O or S, adjacent substituents also may form an aromatic or aliphatic five-, six- or seven-membered ring, and

R⁰⁷ are each, independently of one another, hydrogen, Ci-C₅₀-alkyl, C₂-C₅₀-alkenyl, C5-C₅₀-aryl, arylalkyi or alkylaryl having from 1 to 50 carbon atoms in the alkyl part and 5-50 carbon atoms in the aryl part, C^Cso-alkoxy or C₅-C₅o-aryloxy and two radicals R⁰⁷ may also be joined to form a five- or six-membered ring, R together with R and atoms connecting them may form an aromatic or aliphatic five-, six- or seven-membered nitrogen heterocycle or R⁰³ and R⁰⁴ are identical or different and are each, independently of one another, C Cso-alkyl, C2-C₅₀-alkenyl, C₅-C₅o-aryl, d-Cso-alkoxy, or C₅-C₅₀- aryloxy, wherein the organic radicals R⁰³ and R⁰⁴ may also be substituted by halogens, Ci-C₅o-alkyl, C₂-C₅o-alkenyl, C₅-C5₀-aryl, d-C₅o-alkoxy, C₅-C₅o-aryloxy or SiR⁰⁷ ₃, R⁰³ and R⁰⁴ and their substituents may also contain one or more heteroatoms selected from N, P, O or S, adjacent substituents also may form an aromatic or aliphatic five-, six- or seven-membered ring, and the radicals R⁰⁷ are defined as above,

n, o, p, q are each independently 1 or 2;

Y is a divalent linking group and is selected from -N(R⁰⁵)-, -C(O)-, -C(R⁰⁵R⁰⁶)-, -Si(R⁰⁵R⁰⁶)-, - P(R⁰⁵)- , -P(0)R⁰⁵-, -Ge-,-Ge(R⁰⁵R⁰⁶)-,-Sn- -0-, -S-, -S(O)-, -S(0₂)-,

where R⁰⁵ and R⁰⁶ are identical or different and are each, independently of one another, hydrogen, halogen, d-Cso-alkyl, C2-C₅₀-alkenyl, C₅-C₅₀-aryl, alkylaryl or arylalkyl having from 1 to 50 carbon atoms in the alkyl part and 5-50 carbon atoms in the aryl part, d-Cso-alkoxy, or C₅-C₅₀-aryloxy, where the organic radicals R⁰⁵ and R⁰⁶ may also be substituted by halogens, d-C₅o-alkoxy, C₅-C₅o- aryloxy or SiR⁰⁷ ₃ and two geminal radicals R⁰⁵ and R⁰⁶ may also be joined to form a five- or six- membered ring, the radicals R⁰⁵ and R⁰⁶ and their substituents may also contain heteroatoms selected from N, P, O or S, and the radicals R⁰⁷ are defined as above,

m is 1 or 0;

M is an element of group 3 to 10 of the Periodic Table of the Elements

X is halogen, C₁-C₂o-alkyl, C₂-C₂o-alkenyl, C₅-C₂₂-aryl, alkylaryl or arylalkyl group having from 1 to 10 carbon atoms in the alkyl radical and from 5 to 22 carbon atoms in the aryl radical, -OR⁰⁸ or - NR⁰⁸R⁰⁹, preferably -OR⁰⁸, where two radicals X may also be joined to one another, where R⁰⁸ and R⁰⁹ are each independently d-C₁₀-alkyl, C₅-C₁₅-aryl, alkylaryl, arylalkyl, fluoroalkyl or fluoroaryl each having from 1 to 10 carbon atoms in the alkyl radical and from 5 to 22, carbon atoms in the aryl radical,

r is a natural number from 1 to 5. L¹ and L² are each independently selected from carbon, silicon, germanium, phosphorous, and arsenic, L¹ and L² preferably are the same and are each carbon.

R⁰¹ together with R⁰² and atoms connecting them may form an aromatic or aliphatic five-, six- or seven-membered nitrogen heterocycle or R⁰¹ and R⁰² are identical or different and are each, independently of one another, Ci-C₅₀-alkyl, preferably d-Cio-alkyl, C₂-C₅₀-alkenyl, preferably C₂-C₁₀-alkenyl, C₅-C₅₀-aryl, preferably C₅-Ci -aryl, d-C₅o-alkoxy, preferably Ci-C₁₀-alkoxy, or C₅-C₅₀-aryloxy, preferably C₅-C₁₄-aryloxy where the organic radicals R⁰¹ and R⁰² may also be substituted by halogens, .i.e. by fluorine, bromine, chlorine, or iodine, d-Cso-alkyl, preferably CrC₁₀- alkyl, C₂-C₅o-alkenyl, preferably C₂-C₁₀-alkenyl, C₅-C₅o-aryl, preferably C₅-C₁₄-aryl, d-Cso-alkoxy, preferably d-C₁₀-alkoxy, C₅-C₅₀-aryloxy preferably C₅-C₁ -aryloxy or SiR ₃ and R and R and their substituents may also contain heteroatoms selected from N, P, O or S.

Preferably R⁰¹ together with R⁰² and atoms connecting them may form an aromatic or aliphatic five-, six- or seven-mem bered nitrogen heterocycle, e.g. pyridine, pyrimidine, pyrazine, pyrrol. It is especially preferred that R⁰ together with L¹, R⁰² and the nitrogen atom connecting them form a pyridine ring.

R⁰³ together with R⁰ and atoms connecting them may form an aromatic or aliphatic five-, six- or seven-membered nitrogen heterocycle or R⁰³ and R⁰⁴ are identical or different and are each, independently of one another, Ci-C₅₀-alkyl, preferably Ci-Cio-alkyl, C₂-C₅o-alkenyl, preferably C₂-C₁₀-alkenyl, C₅-C₅₀-aryl, preferably C₅-Ci₄-aryl, (VCso-alkoxy, preferably Ci-Ci₀-alkoxy, or C₅-C₅o-aryloxy, preferably C₅-C₁₄-aryloxy where the organic radicals R⁰³ and R⁰⁴ may also be substituted by halogens, .i.e. by fluorine, bromine, chlorine, or iodine, C^Cso-alkyl, preferably C Cio- alkyl, C₂-C₅₀-alkenyl, preferably C₂-C₁₀-alkenyl, C₅-C₅o-aryl, preferably C₅-C₁₄-aryl, d-Cso-alkoxy, preferably C Cuj-alkoxy, Cs-Cso-aryloxy preferably C₅-C₁₄-aryloxy or SiR⁰⁷ ₃ and R⁰³ and R⁰⁴ and their substituents may also contain one or more heteroatoms selected from N, P, O or S.

Preferably R⁰³ together with R⁰⁴ and atoms connecting them may form an aromatic or aliphatic five-, six- or seven-membered nitrogen heterocycle, e.g. pyridine, pyrimidine, pyrazine, pyrrol. It is especially preferred that R⁰³ together with L², R⁰⁴ and the nitrogen atom connecting them form a pyridine ring.

The radicals R⁰⁷ in organosilicon substitutents SiR⁰⁷ ₃ can be the same or different are each, independently of one another, hydrogen, C^Cso-alkyl, preferably CrC₁₀-alkyl, C₂-C₅₀-alkenyl, preferably C₂-C₁₀-alkenyl, C₅-C₅o-aryl, C₅-C₁₄-aryl, arylalkyl or alkylaryl having from 1 to 50, preferably 1-4 carbon atoms in the alkyl part and 5-50, preferably 5-14 carbon atoms in the aryl part, Ci-C₅₀-alkoxy, preferably Ci-Ci₀-alkoxy or C₅-C₅₀-aryloxy, preferably C₅-C₁₄-aryloxy, where two radicals R⁰⁷ may also be joined to form a 5- or 6-membered ring. Examples for the radicals R⁰⁷ are trimethylsilyl, triethylsilyl, butyldimethylsilyl, tributylsilyl, tritert-butylsilyl, triallylsilyl, triphenylsilyl or dimethylphenylsilyl. Preferred radicals R⁰⁷ are hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, methoxy, ethoxy, propoxy, butoxy, benzyl, phenyl, ortho-dialkyl- or dichloro-substituted phenyls, trialkyl- or trichloro-substituted phenyls, naphthyl, biphenyl and anthranyl. n, o, p, q each independently may be 1 or 2, dependent on whether the respective radicals are connected by single, aromatic or double bonds. E.g. in case R⁰¹, R⁰², L¹, and the nitrogen atom connecting R⁰² and L¹ together form an aromatic system , n and o each are 1. And similarily if R⁰³, R⁰⁴, L², and the nitrogen atom connecting R⁰⁴ and L² together form an aromatic system, p and q each are 1. If, however, only single bonds connect R⁰¹, N, L¹, and R⁰² n and o are each 2.

Y is preferably a group -NR⁰⁵-, -C(O)-, -CR⁰⁵R⁰⁶- with m = 1 , or Y being a bridge, i.e. m representing 0. The preferred embodiments of the substituents R⁰⁵ and R⁰⁶ described above are likewise preferred embodiments here. Especially preferred embodiments of Y are N(R⁰⁵)- bridges, wherein R⁰⁵ is a hydrogen atom, a halogen atom, a tri-Ci-Cso-alkylsilyl group, a tri-C^Cso-alkoxysilyl group, a Ci-C₅₀-alkyl group, a 5- to 7-membered cycloalkyl group or a cycloalkenyl group, a C₂-C₂₂-alkenyl group, a C₆-C₂2-aryl group, a alkylaryl group or a arylalkyl group having from 1 to 10 carbon atoms in the alkyl part and from 6 to 20 carbon atoms in the aryl part, a C₁-C₂o-alkoxy group, or a C₆-C₂₂- aryloxy group, wherein the organic radical R⁰⁵ may also be substituted by tri-C_1-10-alkylsilyl, tri-C_1-10- alkoxysilyl, (^-Cur-alkoxy, C₆-C₁₂-aryloxy and halogen groups with. Most preferred embodiments for Y are N,N-neopentylamine, Ν,Ν-methyl amine, Ν,Ν-hexadecyl amine, Ν,Ν-benzyl amine, N,N- (trimethylsilyl)methyl amine, N,N-(triethoxysilyl)propyl amine.

Preferred carboorganic substituents R⁰⁵and R⁰⁶ on the linkage Y are, for example, the following: hydrogen, C^-C^-alky! which may be linear or branched, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, n-octyl, n-decyl, n-dodecyl, n-hexadecyl 5- to 7-membered cycloalkyl which may in turn bear a C₅-C₂₀-aryl group as substituent, e.g.

cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclododecyl, C₂-C₂₀-alkenyl which may be linear, cyclic or branched and in which the double bond may be internal or terminal, e.g. vinyl, 1-allyl, 2-allyl, 3-allyl, butenyl, pentenyl, hexenyl, cyclopentenyl, cyclohexenyl, cyclooctenyl or cyclooctadienyl, C₆-C₂₀-aryl which may be substituted by further alkyl groups, e.g. phenyl, naphthyl, biphenyl, anthranyl, o-, m-, p-methylphenyl, 2,3-, 2,4-, 2,5- or 2,6-dimethylphen-1- yl, 2,3,4-, 2,3,5-, 2,3,6-, 2,4,5-, 2,4,6- or 3,4,5-trimethylphen-1-yl, or arylalkyl which may be substituted by further alkyl groups, e.g. benzyl, o-, m-, p-methylbenzyl, 1- or 2-ethylphenyl, where R⁰⁵and R⁰⁶ may also be substituted by halogens such as fluorine, chlorine or bromine or SiR⁰⁷ ₃. is a transition metal of group 3 to 10 of the periodic table of the elements or the lanthanides, M is preferably an element of group 3, 4, 5 or 6 of the Periodic Table of the Elements or the lanthanides, for example titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum or tungsten, preferably chromium, molybdenum or tungsten, particularly preferably chromium.

The radicals X are identical or different, preferably identical, with two radicals X also being able to be joined to one another. X is preferably halogen, for example fluorine, chlorine, bromine, iodine, preferably chlorine, CrC₂₀-, preferably ⁽-VCralkyl, in particular methyl, C₂-C₂₀-, preferably C₂-C₄- alkenyl, C₅-C₂₂-, preferably C₅-C₁₀-aryl, an alkylaryl or arylalkyl group having from 1 to 10, preferably from 1 to 4, carbon atoms in the alkyl radical and from 5 to 22, preferably from 5 to 10, carbon atoms in the aryl radical, -OR⁰⁸ or -NR⁰⁸R⁰⁹, preferably -OR⁰⁸, where two radicals X, preferably two radicals -OR , may also be joined to one another. It is also possible for two radicals X to form a substituted or unsubstituted diene ligand, in particular a 1 ,3-diene ligand. The radicals R⁰⁸ and R⁰⁹ are each C Cio-, preferably Ci-C₄-alkyl, C₅-C₁₅-, preferably C₅-C₁₀-aryl, alkylaryl, arylalkyl, fluoroalkyl or fluoroaryl each having from 1 to 10, preferably from 1 to 4, carbon atoms in the alkyl radical and from 5 to 22, preferably from 5 to 10, carbon atoms in the aryl radical.

The variable r is a number from 1 to 5. The number r of the ligands X depends on the oxidation state of the transition metal M. The oxidation state of the transition metals M in catalytically active complexes is usually known to those skilled in the art. E.g. chromium, molybdenum and tungsten are very probably present in the oxidation state +3 and titanium, zirconium, and hafnium in the oxidation state 4, titanium and vanadium can be present in the oxidation state 3. However, it is also possible to use complexes whose oxidation state does not correspond to that of the active catalyst. Such complexes can then be appropriately reduced or oxidized by means of suitable activators. M is preferably chromium chromium in the oxidation states 2, 3 and 6. Chromium is very probably present in the oxidation state +3.

In the above formula (I), and below formulae (IA), (II), and (IIA) as well as throughout the whole specification the terms have the following meanings: The term "alkyl" as used herein refers to a branched or unbranched saturated hydrocarbon group containing 1 to 50 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec- butyl, t-butyl, octyl, decyl, and the like, as well as cycloalkyl groups such as cyclopentyl, cyclohexyl and the like. Generally, alkyl groups herein may contain 1 to 20 carbon atoms. The term "alkenyl" as used herein refers to a branched or unbranched, cyclic or acyclic hydrocarbon group containing 2 to 50 carbon atoms and at least one double bond, such as ethenyl, n-propenyl, isopropenyl, n-butenyl, isobutenyl, octenyl, decenyl, and the like. Generally, alkenyl groups herein contain 2 to 20 carbon atoms. The term "aromatic" is used in its usual sense, including unsaturation that is delocalized across several bonds around a ring. The term "aryl" as used herein refers to a group containing an aromatic ring. Aryl groups herein include groups containing a single aromatic ring or multiple aromatic rings that are fused together, linked covalently, or linked to a common group such as a methylene or ethylene moiety. More specific aryl groups contain one aromatic ring or two or three fused or linked aromatic rings, e.g., phenyl, naphthyl, biphenyl, anthracenyl, or phenanthrenyl. Aryl groups include 5 to 50 atoms other than hydrogen, typically 5 to 20 atoms other than hydrogen. In some embodiments herein, multi-ring moieties are substituents and in such embodiments the multi-ring moiety can be attached at an appropriate atom. For example, "naphthyl" can be 1 -naphthyl or 2- naphthyl; "anthracenyl" can be 1-anthracenyl, 2-anthracenyl or 9-anthracenyl; and "phenanthrenyl" can be 1 -phenanthrenyl, 2-phenanthrenyl, 3-phenanthrenyl, 4-phenanthrenyl, or 9-phenanthrenyl.

The term "alkoxy" as used herein intends an alkyl group bound through a single, terminal ether linkage; that is, an "alkoxy" group may be represented as -O-alkyl where alkyl is as defined above. The term "aryloxy" is used in a similar fashion, and may be represented as -O-aryl, with aryl as defined below. The term "hydroxy" refers to -OH.

The terms "halo" and "halogen" are used in the conventional sense to refer to a chioro, bromo, fiuoro or iodo radical.

The term "containing heteratoms selected from N, P, O or S" refer to a molecule or molecular fragment in which one or more carbon atoms is replaced with a heteroatom. Thus, for example, in view of "alkyl" it refers to an alkyl substituent that is heteroatom-containing. In respect of "cycles" containing a heteroatom one or more carbon atoms in a ring is replaced with a heteroatom-that is, an atom other than carbon, i.e. nitrogen, oxygen, sulfur, phosphorus. The term "aryl containing heteroatoms" refers to an aryl radical that includes one or more heteroatoms in the aromatic ring. Specific heteroaryl groups include groups containing heteroaromatic rings such as thiophene, pyridine, pyrazine, isoxazole, pyrrazole, pyrrole, furan, thiazole, oxazole, imidazole, isothiazole, oxadiazole, triazole, and benzo-fused analogues of these rings, such as indole, carbazole, benzofuran, benzothiophene and the like.

By "divalent" as in "divalent linking group", is meant that the hydrocarbyl, alkyl, aryl or other moiety bound at two points to atoms, molecules or moieties with the two bonding points being covalent bonds.

Special preference is given to organometallic transition metal compounds of the formula (IA)

wherein

M, X, r, Y, and m are defined as for formula (I) above;

and R^A01, R^A02, R^A03, R^A04, R^A0S, R^A06, R^A07, and R^A08, are identical or different and are each hydrogen, halogen, Ci-C₅₀-alkyl, C₂-C₅o-alkenyl, C₅-C5₀-aryl, d-Cso-alkoxy, C₅-C₅o-aryloxy or SiR° and the substituents may also contain heteroatoms selected from N, P, O or S, wherein the radicals R are each, independently of one another, hydrogen, d-Cso-alkyl, C₂-C_3o- alkenyl, C₅-C₅₀-aryl, arylalkyl or alkylaryl having from 1 to 50 carbon atoms in the alkyl part and 5-50 carbon atoms in the aryl part, CrCso-alkoxy or C₅-C₅o-aryloxy and two radicals R⁰⁷ may also be joined to form a five- or six-membered ring.

M, X, r, Y, and R⁰⁷ are defined and their preferred embodiments are as stated above.

R^A01, R^A02, R^A03, R^A04, R^A05, R^A06, R^A07, and R^A08 are identical or different and are each hydrogen, halogen, e.g. fluorine, bromine, chlorine or iodine, CrCso-alkyl, preferably Ci-C₁₀-alkyl, C₂-C₅₀- alkenyl, preferably C₂-C₁₀-alkenyl, C₅-C5₀-aryl, preferably C₅-Ci -aryl, Ci-C₅₀-alkoxy, preferably Ci-C₁₀-alkoxy, C₅-C₅o-aryloxy, preferably C₅-C₁₄-aryloxy or SiR⁰⁷ ₃ and the substituents may also contain heteroatoms selected from N, P, O or S. Especially preferred is R^A01, R^A02, R^A03, R^A04, R^A0S, R^A06, R^A07, and R^A08 being identical and each being hydrogen. Examples for especially preferred compounds are A/-neopentyl-2,2'-dipyridylamine chromium chloride, /V-methyl-2,2'-dipyridylamine chromium chloride, /V-hexadecyl-2,2'-dipyridylamine chromium chloride, /\/-benzyl-2,2'-dipyridylamine chromium chloride, W-(trimethylsilyl)methyl-2,2'- dipyridylamine chromium chloride, W-(triethoxysilyl)propyl-2,2'-dipyridylamine chromium chloride, 2,2'-bispyridyl chromium chloride, 2,2'-dipyridylmethanon chromium chloride.

The present invention further refers to a catalyst system for the oligomerization of olefins, which comprises

a) at least one organometallic transition metal compound of formula (I) or (IA) and

b) at least one cocatalyst which is able to convert the organometallic transition metal compound into a species which is oligoerization-active toward at least one olefin.

It will be appreciated that the above catalyst system may either be formed prior to use in an oligomerization reaction, or it may be formed in situ by adding the individual components thereof to the reaction mixture.

The oligomerization catalyst system may also be formed in-situ by mixing

(a1 ) a transition metal precursor of a transition metal of group 3 to 10 of the Periodic Table of the

Elements and

(a2) a ligand of formula (II)

wherein the radicals are defined like for formula (I) and further component or components Especially preferred ligands are of formula (MA)

wherein the radicals are defined as for formula (IA).

In the case of the transition metal precursor being a chromium precursor, examples for a metal precursor of the present invention care chromium salts in oxidation state +11 or +111 , preferably THF adducts of chromium(ll) and chromium(lll) salts. Examples for these chromium precursors are (THF)₃CrMeCI₂, (THF)₃CrCI₃, (Mes)₃Cr(THF), [{TFA}₂Cr(OEt₂)]₂, (THF)₃CrPh₃, Cr(NMe₃)₂CI₃, CrCI₃, Cr(acac)₃, Cr(2-ethylhexanoate)₃, Cr(neopentyl)₃(THF)₃, Cr(CH₂-C₆H₄-o-NMe₂)₃, Cr(TFA)₃,

Cr(CH(SiMe₃)₂)₃, Cr(Mes)₂(THF)₃, Cr(Mes)₂(THF), Cr(Mes)CI(THF)₂, Cr(Mes)CI(THF)_{0 5}, Cr(p- tolyl)CI₂(THF)_3l Cr(diisopropylamide)₃, Cr(picolinate)_3l CrCI₂(THF)₂, Cr(N0₃)₃, CrCI₂,

Cr(hexafluoroacetylacetonato)_3l (THF)₃Cr(n² -2,2'-Biphenyl)Br as well as mixtures thereof. Especially preferred chromium precursors are (THF)₃CrCI₃, CrCI₃, Cr(acac)₃ , CrCI₂, CrCI₂(THF)₂. The abbreviation used are as follows: Mes=mesityl=2,4,6-trimethylphenyl; TFA=trifluoroacetate;

acac=acetylacetonato; ET= ethyl.

The ligands can be prepared using procedures known to one skilled in the art and disclosed in published literature. Examples of preferred ligands are:

/\/-neopentyl-2,2'-dipyridylamine, /V-methyl-2,2'-dipyridylamine, /V-hexadecyl^^'-dipyridylamine, N- benzyl-2,2'-dipyridylamine, W-(trimethylsilyl)methyl-2,2'-dipyridylamine, A7-(triethoxysilyl)propyl-2,2'- dipyridylamine, 2,2'-bispyridyl chromium chloride, 2,2'-dipyridylmethanon.

As activating agent a co-catalysts b) is also present in the invention. Suitable activators for the types of catalyst mentioned are generally known.

Preferred components (b) are aluminoxanes. It is possible to use, for example, the compounds described in WO 00/31090 A1. Particularly suitable aluminoxanes are open-chain or cyclic aluminoxane compounds of the general formulae (MIA) or (1MB)

where

R is each, independently of one another, a C^Ce-alkyl group, preferably a ethyl, butyl or isobutyl group, and

s is an integer from 1 to 40, preferably from 4 to 25.

A particularly suitable aluminoxane compound is methylaluminoxane.

The catalyst system may also comprise additional to components a) and b) Suitable components are, for example, also strong, uncharged Lewis acids, ionic compounds having Lewis-acid cations or an ionic compounds containing Bronsted acids as cations. Examples are

tris(pentafluorophenyl)borane, tetrakis(pentafluorophenyl)borate or salts of N,N-dimethylanilinium.

The catalyst system may further comprise, as additional component c), a metal compound of general formula (IV),

M^,v (R^lv1)_t (R^lv2)_u (R^,V3)_v (IV)

where

IV

M is lithium, sodium, potassium, beryllium, magnesium, calcium, strontium, barium, boron, aluminum, gallium, indium, thallium, zinc, preferably lithium, sodium, potassium, magnesium, boron, aluminum or zinc and in particular lithium, magnesium, boron or aluminum,

IV1

R is hydrogen, C-i-Cio-alkyl, C₆-C₁₅-aryl, alkylaryl or arylalkyl each having from 1 to

16 carbon atoms in the alkyl radical and from 6 to 20 carbon atoms in the aryl radical, preferably C₁-C₂₀-alkyl

R^IV2 and R are each hydrogen, halogen,

C₆-C₁₅-aryl, alkylaryl, arylalkyl or alkoxy each having from 1 to 20 carbon atoms in the alkyl radical and from 6 to 20 carbon atoms in the aryl radical, or alkoxy with Ci-Ci₀-alkyl or C₆-Ci₅-aryl,

t is an integer from 1 to 3

and

u and v are integers from 0 to 2, with the sum t+u+v corresponding to the valence of M^IV It is also possible to use mixtures of various metal compounds of the formula (IV). Particularly preferred metal compounds of the formula (IV) are methyllithium, ethyllithium, n-butyllithium, methylmagnesium chloride, methylmagnesium bromide, ethylmagnesium chloride, ethylmagnesium bromide, butylmagnesium chloride, dimethylmagnesium, diethylmagnesium, dibutylmagnesium, n- butyl-n-octylmagnesium, n-butyl-n-heptylmagnesium, preferably n-butyl-n-octylmagnesium, tri- n-hexylaluminum, triisobutylaluminum, tri-n-butylaluminum, triethylaluminum, dimethylaluminum chloride, dimethylaluminum fluoride, methylaluminum dichloride, methylaluminum sesquichloride, diethylaluminum chloride and trimethylaluminum and mixtures thereof. The partial hydrolysis products of aluminum alkyls with alcohols can also be used.

If a metal compounds of general formula (III) is used, it is preferably comprised in the catalyst system in such an amount that the molar ratio of M from formula (III) to the sum of all metals of catalyst components a) and b) is from 3000: 1 to 0.1 : 1 , preferably from 800:1 to 0.2:1 and particularly preferably from 100:1 to 1 :1.

For carrying out the process of the present invention in gas-phase or in suspension it is often advantageous to use a catalyst system comprising oligomerization catalyst components a) and b) in solid form. Accordingly, in a preferred embodiment of the present invention catalyst at least one of components a) and b) are applied to a solid support.

To prepare the catalyst systems of the invention, preference is given to immobilizing component a) on the support by physisorption or else by means of a chemical reaction, i.e. covalent binding of the components, with reactive groups on the support surface. Transition metal complex a), and the cocatalyst b) can be immobilized independently of one another, e.g. in succession or simultaneously. Thus, the support component can firstly be brought into contact with the cocatalyst or cocatalysts b) or the support component can firstly be brought into contact with the transition metal complex a). Preactivation of the transition metal complex a) by means of one or more cocatalysts b) prior to mixing with the support is also possible. The immobilization is generally carried out in an inert solvent which can be removed by filtration or evaporation after the immobilization. After the individual process steps, the solid can be washed with suitably inert solvents such as aliphatic or aromatic hydrocarbons and dried. However, the use of the still moist, supported catalyst is also possible. As support component, preference is given to using finely divided supports which can be any organic or inorganic solid. In particular, the support component can be a porous support such as talc, a sheet silicate such as montmorillonite, mica or an inorganic oxide or a finely divided polymer powder (e.g. polyolefin or a polymer having polar functional groups). The inorganic support can be subjected to a thermal treatment, e.g. to remove adsorbed water. Such a drying treatment is generally carried out at temperatures in the range from 50 to 1000°C, preferably from 100 to 600°C, with drying at from 100 to 200°C preferably being carried out under reduced pressure and/or under a blanket of inert gas (e.g. nitrogen), or the inorganic support can be calcined at temperatures of from 200 to 1000°C to produce the desired structure of the solid and/or set the desired OH concentration on the surface. The support can also be treated chemically using customary dessicants such as metal alkyls preferably aluminum alkyls, chlorosilanes or SiCI₄, or else methylaluminoxane.

Appropriate treatment methods are described, for example, in WO 00/31090 A1.

The invention further refers to a process for olefin oligomerization, especially tetramerization, carried out in the presence of a catalyst system as defined above.

In this specification the term "tetramerization" means catalytic reaction of a single olefinic monomer or a mixture of olefinic monomers to give products enriched in those constituents derived from the reaction(s) of four olefinic monomers, as distinct from polymerization. "Tetramerization" includes the case where all the monomer units in the tetramerization product are identical, where the

tetramerization product is made from two different olefins (i.e. two equivalents of one monomer react with two equivalents of a second monomer), and also where four different monomer units react to yield the product. A reaction involving more than one monomer is often referred to as co- tetramerization. The term "tetramerization" generally refers to the reaction of four, and preferably four identical, olefinic monomer units or a-olefins to yield a linear and/or branched olefin. Under the term a-olefinic monomer units or a-olefins is meant all hydrocarbon compounds with terminal double bonds. This definition includes ethylene, propylene, 1-butene, isobutylene, 1-pentene, 1-hexene, 1- octene and the like. In the present application the term "oligomerization" means catalytic reaction of a single olefinic monomer or a mixture of olefinic monomers to give products enriched in those constituents derived from the reaction(s) of 2 to 15 olefinic monomers.

The cocatalyst or cocatalysts b) (also referred to as activating compound(s)) can in each case be used in any amounts based on the complexes a) of the catalyst composition of the invention. They are preferably used in an excess or in stoichiometric amounts, in each case based on the complex a) which they activate. The amount of activating compound(s) to be used depends on the type of the cocatalyst b). In general, the molar ratio of transition metal complex a) to activating compound b) can be from 1 :0.1 to 1 :10000, preferably from 1 :1 to 1 :2000.

Suitable olefinic monomers, or combinations thereof for use in the tetramerization process of the present invention are hydrocarbon olefins, for example, ethylene, C₃-C₂o a-olefins, internal olefins, vinylidene olefins, cyclic olefins and dienes, propylene, 1-butene, 1-pentene, 1-hexene, 4- methylpentene-1 , 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1- eicosene, styrene, 2-butene, 2-ethyl-1-hexene, cyclohexene, norbomene, butadiene and 1 ,5- bexadiene. Olefins with a polar functionality, such as methyl (meth)acrylate, vinyl acetate, α,ω- undecenol and the like, may also be used. The preferred monomer is ethylene. Mixtures of these monomers may also be used, for example a 1-butene unit and three ethylene units may be co- tetramerised to form C₁₀ olefins, or 1-hexene and ethylene co-tetramerised to C₁₂ olefins, or 1- dodecene and ethylene co-tetramerised to C₁₈ olefins. Combinations of these co-tetramerization reactions may be performed simultaneously, especially when one or more of the monomers are produced in-situ (e.g. a mixture of ethylene and butene can be used to form mixtures containing predominantly hexenes, octenes, and decenes.) Techniques for varying the distribution of products from these reactions include controlling process conditions (e.g. concentration, reaction

temperature, pressure, residence time) and properly selecting the design of the process and are well known to those skilled in the art. Olefinic monomers or mixtures of olefinic monomers for oligomerization may be substantially pure or may contain olefinic impurities. One embodiment of the process of the invention comprises the oligomerization, preferably tetramerization of olefin-containing waste streams from other chemical processes or other stages of the same process. When operating under solution or slurry phase conditions, any diluent or solvent that is an olefin, a mixture of olefins, or is substantially inert under tetramerization conditions may be employed.

Mixtures of inert diluents, with or without one or more olefins, also could be employed. The preferred diluents or solvents are aliphatic and aromatic hydrocarbons and halogenated hydrocarbons such as, for example, isobutane, pentane, toluene, xylene, ethylbenzene, cumene, mesitylene, beptane, cyclohexane, methylcyclohexane, 1-hexene, 1-octene, chlorobenzene, dichlorobenzene, and the like, and mixtures such as isopar.

The oligomerization can be carried out in a known manner in bulk, in suspension, in the gas phase or in a supercritical medium in the customary reactors used for the oligomerization or polymerization of olefins. It can be carried out batchwise or continuously in one or more stages. High-pressure oligomerization processes in tube reactors or autoclaves, solution processes, suspension processes, stirred gas-phase processes or gas-phase fluidized-bed processes are all possible.

The oligomerizations are usually carried out at temperatures in the range from -60 to 350°C and under pressures of from 0.5 to 4000 bar. The mean residence times are usually from 0.5 to 5 hours, preferably from 0.5 to 3 hours. The advantageous pressure and temperature ranges for carrying out the oligomerizations usually depend on the oligomerization method. In the case of high-pressure oligomerization processes, which are usually carried out at pressures of from 1000 to 4000 bar, in particular from 2000 to 3500 bar, high oligomerization temperatures are generally also set. Advantageous temperature ranges for these high-pressure oligomerization processes are from 200 to 320°C, in particular from 220 to 290°C. In the case of low-pressure oligomerization processes, a temperature which is at least a few degrees below the softening temperature of the oligomer is generally set. In particular, temperatures of from 50 to 180°C, preferably from 70 to 120°C, are set in these oligomerization processes. The oligomerization temperatures are generally in the range from - 20 to 115°C, and the pressure is generally in the range from 1 to 100 bar. The solids content of the suspension is generally in the range from 10 to 80%. The oligomerization can be carried out batchwise, e.g. in stirring autoclaves, or continuously, e.g. in tube reactors, preferably in loop reactors. Particular preference is given to employing the Phillips PF process as described in US- A 3 242 150 and US-A 3 248 179. The gas-phase oligomerization is generally carried out in the range from 30 to 125°C.

There exist a number of options for the oligomerization reactor including batch, semi-batch, and continuous operation. The oligomerization and co- oligomerization reactions of the present invention can be performed under a range of process conditions that are readily apparent to those skilled in the art: as a homogeneous liquid phase reaction in the presence or absence of an inert hydrocarbon diluent such as toluene or heptanes; as a two-phase liquid/liquid reaction; as a slurry process where the catalyst is in a form that displays little or no solubility; as a bulk process in which essentially neat reactant and/or product olefins serve as the dominant medium; as a gas-phase process in which at least a portion of the reactant or product olefin(s) are transported to or from a supported form of the catalyst via the gaseous state. The oligomerization reactions may be performed in the known types of gas-phase reactors, such as circulating bed, vertically or horizontally stirred-bed, fixed-bed, or fluidized-bed reactors, liquid-phase reactors, such as plug-flow, continuously stirred tank, or loop reactors, or combinations thereof. A wide range of methods for effecting product, reactant, and catalyst separation and/or purification are known to those skilled in the art and may be employed: distillation, filtration, liquid-liquid separation, slurry settling, extraction, etc. It is within the scope of this invention that an oligomerization product, preferably a tetramerization product might also serve as a reactant (e.g. 1-octene, produced via the tetramerization of ethylene, might be converted to tetradecene products via a subsequent co-tetramerization reaction with ethylene.

An example of an "in situ" process is the production of branched polyethylene catalyzed by components a1 ), a2), and b) , added in any order such that the active catalytic species derived from components (a1 ), (a2) and b) is/are at some point present in a reactor. In the slurry phase process and the gas phase process, the catalyst is generally supported and metered and transferred into the oligomerization zone in the form of a particulate solid either as a dry powder (e.g. with an inert gas, ethylene or an olefin) or as a slurry. In addition, an optional cocatalyst can be fed to the oligomerization zone, for example as a solution, separately from or together with the solid catalyst. The catalyst components a), - or a1 ) and a2)- and b) and optionally c) can be added to any part of the oligomerization reactor either on the same support particle or as a physical mixture on different support particles, or may be added separately to the same or different parts of the reactor sequentially in any order or simultaneously. Alternatively, the components may be unsupported and independently added to any part of the oligomerization reactor simultaneously or sequentially together or separately.

Methods for operating gas phase oligomerization processes are well known in the art. Such methods generally involve agitating (e.g. by stirring, vibrating or fluidizing) a bed of catalyst, and feeding thereto a stream of monomer (under conditions such that at least part of the monomer oligomerizes in contact with the catalyst in the bed. The bed is generally cooled by the addition of cool gas (e.g. recycled gaseous monomer) and/or volatile liquid (e.g. a volatile inert hydrocarbon, or gaseous monomer which has been condensed to form a liquid)..

The gas phase process can be operated under batch, semi-batch, or so-called "continuous" conditions. It is preferred to operate under conditions such that monomer is continuously recycled to an agitated oligomerization zone containing oligomerization catalyst, make-up monomer being provided to replace oligomerized monomer, and continuously or intermittently withdrawing produced oligomer from the oligomerization zone at a rate comparable to the rate of formation of the oligomer, fresh catalyst being added to the oligomerization zone to replace the catalyst withdrawn from the oligomerization zone with the produced oligomer.

Methods for operating gas phase fluidized bed processes for making polyethylene, ethylene copolymers, polypropylene and oligomers of ethylene are well known in the art. The process can be operated, for example, in a vertical cylindrical reactor equipped with a perforated distribution plate to support the bed and to distribute the incoming fluidizing gas stream through the bed. The fluidizing gas circulating through the bed serves to remove the heat of oligomerization or polymerization from the bed and to supply monomer in the bed. Thus the fluidizing gas generally comprises the monomer(s) normally together with some inert gas (e.g. nitrogen or inert hydrocarbons such as methane, ethane, propane, butane, pentane or hexane) and optionally with hydrogen as molecular weight modifier. The hot fluidizing gas emerging from the top of the bed is led optionally through a velocity reduction zone (this can be a cylindrical portion of the reactor having a wider diameter) and, if desired, a cyclone and or filters to disentrain fine solid particles from the gas stream. The hot gas is then led to a heat exchanger to remove at least part of the heat of oligomerization or

polymerization. Catalysts are preferably fed continuously or at regular intervals to the bed. Oligomer is produced continuously within the bed by the oligomerization of the monomer(s). Preferably means are provided to discharge oligomer from the bed continuously or at regular intervals to maintain the fluidized bed at the desired height. The process is generally operated at relatively low pressure, for example, at 10 to 50 bars, and at temperatures for example, between 50 and 135°C. In the gas phase fluidized bed process for oligomerization and polymerization of olefins the heat evolved by the exothermic reaction is normally removed from the polymerization or oligomerization zone (i.e. the fluidized bed) by means of the fluidizing gas stream as described above. The hot reactor gas emerging from the top of the bed is led through one or more heat exchangers wherein the gas is cooled. The cooled reactor gas, together with any make-up gas, is then recycled to the base of the bed. In the gas phase fluidized bed process it is desirable to provide additional cooling of the bed (and thereby improve the space time yield of the process) by feeding a volatile liquid to the bed under conditions such that the liquid evaporates in the bed thereby absorbing additional heat of polymerization and oligomerization from the bed by the "latent heat of evaporation" effect. When the hot recycle gas from the bed enters the heat exchanger, the volatile liquid can condense out. In one embodiment of the present invention the volatile liquid is separated from the recycle gas and reintroduced separately into the bed. Thus, for example, the volatile liquid can be separated and sprayed into the bed. In another embodiment of the present invention the volatile liquid is recycled to the bed with the recycle gas. Thus the volatile liquid can be condensed from the fluidizing gas stream emerging from the reactor and can be recycled to the bed with recycle gas, or can be separated from the recycle gas and then returned to the bed.

The tetramerization catalyst is preferably (but optionally) added before the oligomerization catalyst such that the desired primary monomer to comonomer(s) ratio is established prior to introduction of the oligomerization catalyst. The desired comonomer composition at start-up may however be achieved through introduction of fresh comonomer feed or through judicious initiation of the tetramerization reaction before or during oligomerization catalyst introduction. The present invention is illustrated in the following Examples.

EXAMPLES

All reactions concerning synthesis of the catalyst were carried out under a dry nitrogen atmosphere in Schlenk line or in a purified nitrogen-filled dry box. Solvents were dried using an aluminium oxide solvent purification system except for anhydrous DMF (dimethyl formamide) which was purchased from Sigma-Aldrich and used as received. 2,2'-dipyridylamine, 1-chloro-2,2-dimethylpropane and any other alkyl halide used for the synthesis of the ligands were purchased from Sigma-Aldrich and used without further purification. Potassium hydride was purchased from Strem Chemicals and washed with hexane and dried prior to use. CrCI₃(THF)₃ and CrCI₂(THF)₂ were prepared according to standard procedures. MAO (methylaluminoxane, 10% wt. in Toluene) was purchased from Sigma- Aldrich. Ethylene was purchased from BOC Gases (polymer grade 3.0) and used as received. Data for X-ray crystal structure determination were obtained with a Bruker diffractometer equipped with a 1 K Smart CCD area detector. NMR spectra were collected on a Bruker 300 MHz instrument. Methylalumoxane (MAO) used for supportation reactions was received from Chemtura as a 30% wt/wt toluene solution.

Support pretreatment (calcination)

a) XPO-2326, a spray-dried silica gel from Grace, was calcinated at 600°C for 6 hours and subsequently 2.5 Kg of the dried silica gel were put into a 10 L vessel and cooled at 10°C.

b) XPO-2107, a spray-dried silica gel from Grace, was baked at 600°C for 6 hours and subsequently admixed with 3 mmol of MAO per g of baked silica gel and the solvent was subsequently removed under reduced pressure.

Support pretreatment (heating)

a) XPO-2326, a spray-dried silica gel from Grace, was heated at 130°C for 8 hours and subsequently 1.0 Kg of the dried silica gel were put into a 10 L vessel and cooled at 10°C.

Example 1 :

1.1 Synthesis of N-neopentyl-2,2'-dipyridylamine

In a two-necked flask equipped with condenser 2,2'-dipyridylamine (10 g, 54.5 mmol) was dissolved in dry DMF (100 ml) and the resulting solution was stirred under N₂ at 0°C for 15 min. Potassium hydride (1.2 eq., 65.4 mmol) was added portion wise and the resulting solution was stirred at 0°C for 1.5h. 1-chloro-2,2-dimethylpropane (1.3 eq, 71 mmol) was added in one portion and the resulting yellow/green solution was refluxed at 70-75°C for 2 days after which 10 ml of ethanol were added to quench the reaction. After stirring the reaction solution for 20 min, the solvent was evaporated under reduced pressure and the resulting thick yellow oil was treated with ether (30 ml). The resulting yellow suspension was filtered and the liquid organic phase was evaporated under reduced pressure to give yellow oil which was purified by column chromatography on silica gel (Hexane/AcOEt 7/3). The pure product was obtained as white crystalline material (9.72 g, 74% yield).

1.2 Synthesis of Cr(lll) complex

The complexation was carried out in dry box. In a 50 ml flask the ligand (3 mmol) was dissolved in toluene (20 ml, most commonly used solvent). To the resulting clear colorless solution CrCI₃(THF)₃ was added (0.98 eq., 2.94 mmol, 1 ,10 g). The resulting suspension was stirred at room temperature for 24h while the color slowly changes from purple into green. With no stirring the green complex decants leaving the solvent totally colorless. The green powder was filtered and washed with toluene (6 ml) and hexane (2 x 6 ml) and finally dried under reduced pressure (1.36 g, >98% yield; in the case of the neopentyl ligand the chemical formula determined according to crystal structure and other experimental data is C₁₉H₂7Cl₃CrN₃0 (or LCrCI₃THF) which formula weight is 471 ,79 g/mol) Example 2

2.1 Synthesis of A/-methyl-2,2'-dipyridylamine

The synthesis of the ligand was performed according to the description under 1.1 in Example 1 with the exception that instead of 1-chloro-2,2-dimethylpropane iodomethane 1.3 eq, 70.8 mmol) was added. The product was obtained as pale yellow oil (5.4 g, 50% yield).

Example 3

3.1 Synthesis of /V-hexadecyl-2,2'-dipyridylamine

The synthesis of the ligand was performed according to the description under 1.1 in Example 1 with the exception that instead of 1-chloro-2,2-dimethylpropane 1-bromohexadecane (1.3 eq, 70.8 mmol) was added. The product was obtained as white crystalline material (17.25 g, 85% yield).

Example 4

4.1 Synthesis of A/-benzyl-2,2'-dipyridylamine

The synthesis of the ligand was performed according to the description under 1.1 in Example 1 with the exception that instead of 1-chloro-2,2-dimethylpropane benzylchloride (1.3 eq, 70.8 mmol) was added. The product was obtained as pale yellow crystals (10.7 g, 70% yield). Example 5

5.1 Synthesis of /V-(trimethylsilyl)methyl-2,2'-dipyridylamine

The synthesis of the ligand was performed according to the description under 1.1 in Example 1 with the exception that instead of 1-chloro-2,2-dimethylpropane (chloromethyl)trimethylsilane (1.3 eq, 70.8 mmol) was added. The product was obtained as pale yellow oil (9.5 g, 67% yield).

Example 6

6.1 Synthesis of A/-(triethoxysilyl)propyl-2,2'-dipyridylamine

The synthesis of the ligand was performed according to the description under 1.1 in Example 1 with the exception that instead of 1-chloro-2,2-dimethylpropane (3-chloropropyl)triethoxysilane (1.3 eq, 70.8 mmol) was added. The product was obtained as colorless oil (15.4 g, 75% yield).

Example 7

7.1 Synthesis of 2, 2'-bispyridyl

Available from Aldrich Example 8

8.1 Synthesis of 2,2'-dipyridylmethanon

Available from Aldrich Example 9

Oliqomerization in an 1 I glass autoclave

A Parr reactor was dried in an oven at 1 15°C overnight prior to each run and then placed under vacuum for 1 h at 120°C. The reactor was then cooled to 50°C and charged with toluene (85.5 ml), MAO (400 eq., 8 mmol, -4.6 ml of a 10% wt solution in toluene) and 200 psi of ethylene with stirring. After 15 min the pressure was momentarily released to allow injecting the catalyst (20 μηιοΙ, fin suspension in 10 ml of toluene, prepared in dry box) into the reactor under a stream of ethylene and then the reactor was immediately repressurized with ethylene (600 psi). The reaction was allowed to run for 30 min while maintaining the temperature below 90°C. The temperature was then rapidly reduced to 5°C with an ice bath; the reactor was depressurized and a mixture of MeOH/HCI cone. (45ml/5ml) was injected to quench the reaction. The resulting oligomers and polymers were separated from the organic and aqueous phases by press filtration and dried at 60 °C for 18 h under reduced pressure before the final mass was weighed. The organic phase was separated from the aqueous phase and analysis and yield of oligomers were obtained respectively by GC by using calibrated standard solutions by ^*H-NMR, integrating the intensity of the olefinic resonances versus the Ph and the Me group of the toluene solvent. Precautions were taken to maintain the temperature as low as possible during the workup to minimize loss of volatiles. Process conditions and results are listed in Table 1.

Table 1

Results from homogeneous oligomerization catalyst performance

Example 10

Supportation of M-(triethoxysilyl)propyl-2,2'-dipyridylamine chromium trichloride

1.0 kg of spray-dried Sylopol XPO 2326 obtained from Grace GmbH & Co. KG, Worms, Germany were heated at 130°C for 8 hours and then stored at 10°C. 179.1 mg of 2,2-dipyridyl

(propyltriethoxysilane) amine chromium trichloride (MW: 533.9 g/mol) obtained in Example 6 was dissolved in 220 ml toluene. The solution was added to 6.7 g of the pre-treated spray-dried silica at 0°C. After 30 min stirring at 0°C the colourless solution was removed and a pale green coloured chromium-silica support was obtained. To the chromium-silica support 6.3 ml MAO and 100 ml Toluene were added at 0°C. The suspension was stirred for 30 min at 0°C and 30 min at room temperature. The color of the solution turned dark green. The suspension was filtered over an argon overlaid frit and the obtained solid was dried under argon flow. 7 g of an oyster white coloured powder was obtained.

The theoretical loading was 50 mol of 2,2-dipyridyl(propyltriethoxysilane)amine chromium trichloride and the theoretical molar ratio of AI:Cr was 90:1.

Example 11

Oligomerization in an 1 I Steel autoclave

A 1 I Steel autoclave was flushed with Argon at 70°C. Then 150 mg Triisobutylaluminium (TIBA in heptane 50 mg/ml) as well as 50 mg Costelan AS 100 (Costelan in heptane 50mg/ml) were added. Afterward 400 ml isobutane were pressed with ethylene into the autoclave and the pressure was adjusted to 26 bar with ethylene. 183 mg of the catalyst obtained in example 9 was then added, by a lance to avoid contact with air. The pressure of 26 bar at 70°C was kept constant for 1 hour via adding additional ethylene fed in constant ratio to ethylene variable from 0 to 0.1 ml/g, during the oligomerization. After one hour the pressure was released and the oligomer was removed from the autoclave. Process conditions and results are listed in Table 2.

Table 2

Results from supported oligomerization catalyst performance

Selectivity in the sense of this application means selectivity in view of isomers produced during oligomerization.

Claims

An organometallic transition metal compound of the formula (I)

wherein

L¹ and L² are each independently selected from carbon, silicon, germanium, phosphorous, and arsenic, together with R and the atoms connecting them may form an aromatic or aliphatic five-, six- or seven-membered nitrogen heterocycle or R⁰¹ and R⁰² are identical or different and are each, independently of one another, Ci-C₅₀-alkyl, C₂-C₅₀-alkenyl, Cs-Cso-aryl, C^Cso-alkoxy, or C₅-C₅₀-aryloxy, wherein the organic radicals R⁰¹ and R⁰² may also be substituted by halogens, Ci-C₅₀-alkyl, C₂-C₅o-alkenyl, C₅-C₅₀-aryl, Ci-C₅o-alkoxy, C₅-C₅o-aryloxy or SiR⁰⁷ ₃, R⁰¹ and R⁰² and their substituents may also contain one or more heteroatoms selected from N, P, O or S, adjacent substituents also may form an aromatic or aliphatic five-, six- or seven-membered ring, and are each, independently of one another, hydrogen, Ct-Cso-alkyl, C₂-C₅₀-alkenyl, Cs-Cso-aryl, arylalkyl or alkylaryl having from 1 to 50 carbon atoms in the alkyl part and 5-50 carbon atoms in the aryl part, Ci-Cso-alkoxy or C₅-C₅o-aryloxy and two radicals R⁰⁷ may also be joined to form a five- or six-membered ring, together with R⁰⁴ and atoms connecting them may form an aromatic or aliphatic five-, six- or seven-membered nitrogen heterocycle or R⁰³ and R⁰⁴ are identical or different and are each, independently of one another, C^Cso-alky!, C₂-C₅₀-alkenyl, C₅-C₅₀-aryl, d-Cso-alkoxy, or C₅-C₅o-aryloxy, wherein the organic radicals R⁰³ and R⁰⁴ may also be substituted by halogens, C^Cso-alky!, C₂-C₅₀-alkenyl, Cs-Cso-aryl, C Cso-alkoxy, Cs-Cso-aryloxy or SiR⁰⁷ ₃, R⁰³ and R⁰⁴ and their substituents may also contain one or more heteroatoms selected from N, P, O or S, adjacent substituents also may form an aromatic or aliphatic five-, six- or seven-membered ring, and the radicals R⁰⁷ are defined as above, n, o, p, q are each independently 1 or 2; Y is a divalent linking group and is selected from

-N(R⁰⁵)-, -C(O)-, -C(R⁰⁵R⁰⁶)-, -Si(R⁰⁵R⁰⁶)-, -P(R⁰⁵)- , -P(0)R⁰⁵-, -Ge-, -Ge(R⁰⁵R⁰⁶)-,

-Sn- -0-, -S-, -S(O)-, -S(0₂)-,

wherein

R⁰⁵and R⁰⁶ are identical or different and are each, independently of one another,

hydrogen, halogen, CrC₅o-alkyl, C₂-C₅₀-alkenyl, C₅-C₅o-aryl, alkylaryl or arylalkyl having from 1 to 50 carbon atoms in the alkyl part and 5-50 carbon atoms in the aryl part, CrCso-alkoxy, or C₅-C₅o-aryloxy, where the organic radicals R⁰⁵ and R⁰⁶ may also be substituted by halogens, CrCso-alkoxy, C₅-C₅o-aryloxy or SiR⁰⁷ ₃ and two geminal radicals R⁰⁵ and R⁰⁶ may also be joined to form a five- or six-membered ring, the radicals R⁰⁵ and R⁰⁶ and their substituents may also contain heteroatoms selected from N, P, O or S, wherein the radicals R⁰⁷ are defined as above, m is 1 or 0;

M is an element of group 3 to 10 of the Periodic Table of the Elements

X is halogen, C₁-C₂o-alkyl, C₂-C₂o-alkenyl, C₅-C₂₂-aryl, alkylaryl or arylalkyl group having from 1 to 10 carbon atoms in the alkyl radical and from 5 to 22 carbon atoms in the aryl radical, -OR⁰⁸ or -NR⁰⁸R⁰⁹, preferably -OR⁰⁸, where two radicals X may also be joined to one another, where R⁰⁸ and R⁰⁹ are each independently

C Cw-alkyl, C₅-C₁₅-aryl, alkylaryl, arylalkyl, fluoroalkyl or fluoroaryl each having from 1 to 10 carbon atoms in the alkyl radical and from 5 to 22, carbon atoms in the aryl radical, r is a natural number from 1 to 5.

wherein M, X, r, Y, and m are defined as for formula (I) in claim 1 ; and

R^A01, R^A02, R^A03, R^AtM, R^A05, R^A06, R^A07, and R^A08 are identical or different and are each hydrogen, halogen, d-Cso-alkyl, C₂-C₅₀-alkenyl, C₅-C₅₀-aryl, Ci-Cso-alkoxy, C₅-C₅₀-aryloxy or SiR⁰⁷3, wherein the radicals R^A01, R^A02, R^A03, R^AM, R^A05, R^A06, R^A07, and R^A08 may also contain heteroatoms selected from N, P, O or S, adjacent radicals R^A01, R^A02, R^A03, R^A04, R^A0S, R^A06, R^A07, and R^A08 also may form an aromatic or aliphatic five-, six- or seven-membered ring, and the radicals R⁰⁷are each, independently of one another, hydrogen, C Cso-alkyl, C₂-C₅o- alkenyl, C₅-C₅₀-aryl, arylalkyl or alkylaryl having from 1 to 50 carbon atoms in the alkyl part and 5-50 carbon atoms in the aryl part, C^Cso-alkoxy or C₅-C₅₀-aryloxy and two radicals R⁰⁷ may also be joined to form a five- or six-membered ring.

A li and of the formula (II)

where the variables L¹, L², Y, m, n, o, p, q, R⁰¹, R⁰², R⁰³, R⁰⁴, are as defined for the formula (I).

4. The ligand of claim 3 defined by formula (IIA)

wherein

A05 _DA06 _DA07 _DA08

the variables R^A01, R^A02, R^A03, R^A04, Y, m, R^MUO, R^AUO, R^AU', R^Aue are as defined for formula (IA)

5. A catalyst system for the oligomerization of olefins, which comprises the product obtained by contacting

a) at least one organometallic transition metal compound as claimed in claim 1 or 2 and b) at least one cocatalyst which is able to convert the organometallic transition metal compound into a species which is oligomerization-active toward at least one olefin. A catalyst system for the oligomerization of olefins, comprising the product obtained by contacting:

a1) a transition metal precursor of a transition metal of group 3 to 10 of the Periodic Table of the Elements and

a2) at least one ligand claimed in claim 3 or 4 and

b) at least one cocatalyst which is able to convert the organometallic transition metal compound into a species which is oilgomerization-active toward at least one olefin.

The catalyst system according to claim 5 or 6,

further comprising a support.

A process for the oligomerization of olefinic monomers, carried out in the presence of a catalyst system according to one of claims 5 to 7.

The process of claim 8 for the oligomerization of ethylene, optionally with other olefin monomers.

The process of claim 8 or 9 wherein the oligomerization is a tetramerization.