KR20170018636A

KR20170018636A - Ligand compound, organic chromium compound, catalyst system for oligomerization of olefins and method for oligomerization of olefins using the catalyst system

Info

Publication number: KR20170018636A
Application number: KR1020150112517A
Authority: KR
Inventors: 신은지; 이기수; 이용호; 손경선; 박종은
Original assignee: 주식회사 엘지화학; 충남대학교산학협력단
Priority date: 2015-08-10
Filing date: 2015-08-10
Publication date: 2017-02-20
Also published as: KR102026889B1

Abstract

The present invention relates to a ligand compound, a catalyst system for olefin oligomerization, and an oligomerization method of olefin using the same. The ligand compound according to the present invention can be applied to the catalyst system for olefin oligomerization, thereby being able to exhibit improved 1-hexene selectivity and catalytic activity.

Description

FIELD OF THE INVENTION The present invention relates to a ligand compound, an organic chromium compound, a catalyst system for olefin oligomerization, and an oligomerization method of an olefin using the same. BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to a catalyst system for olefin oligomerization comprising a ligand compound, an organochrome compound, a ligand compound or an organic chromium compound, and a method for oligomerization of an olefin using the same.

Linear alpha-olefins such as 1-hexene, 1-octene and the like are used as cleaning agents, lubricants, plasticizers and the like. Especially, as a monomer for controlling the density of polymers in the production of linear low density polyethylene (LLDPE) Is used.

These linear alpha-olefins were produced mainly through the Shell Higher Olefin Process. However, since the alpha-olefins of various lengths are simultaneously synthesized in accordance with the Schultz-Flory distribution, the method requires a separate separation step in order to obtain a specific alpha-olefin.

In order to solve this problem, a method of selectively synthesizing 1-hexene through trimerization of ethylene or selectively synthesizing 1-octene through a tetramerization reaction of ethylene has been proposed. A number of studies have been conducted on a catalyst system capable of oligomerizing such selective ethylene.

However, up to now, the oligomerization catalyst system of olefins was insufficient in catalytic activity and selectivity to alpha-olefins. In addition, the production efficiency of the polyolefin wax can not be sufficiently secured with the prior art catalyst system, and therefore, there is a need to supplement this.

The present invention is to provide a novel ligand compound capable of exhibiting improved 1-hexene selectivity and catalytic activity in the oligomerization reaction of olefins.

The present invention also provides a novel chromium complex capable of exhibiting improved 1-hexene selectivity and catalytic activity in oligomerization of olefins.

The present invention also provides a catalyst system for olefin oligomerization comprising the ligand compound or the chromium complex.

The present invention also provides a method for oligomerization of olefins using the catalyst system.

According to the present invention, there is provided a ligand compound represented by the following Formula 1:

[Chemical Formula 1]

In Formula 1,

N is nitrogen;

B is phosphorus (P), arsenic (As) or antimony (Sb);

R ¹ to R ¹⁴ are each independently hydrogen, a hydrocarbyl group having 1 to 10 carbon atoms or a heterohydrocarbyl group,

At least one of R ¹ to R ⁴ , at least one of R ⁵ to R ⁹ , or at least one of R ¹⁰ to R ¹⁴ is independently a hydrocarbyl group or a heterohydrocarbyl group having 1 to 10 carbon atoms, or

R ⁹ and R ¹⁰ are connected to form a single bond and the remaining group is hydrogen.

According to the present invention, a complex compound in which a chromium compound is coordinated to the ligand compound is provided.

And, according to the present invention, there is provided a process for preparing a chromium source, comprising: i) a chromium source, the ligand compound and a cocatalyst; Or ii) a catalyst system for olefin oligomerization comprising the complex and the cocatalyst.

According to the present invention, there is provided a method for oligomerization of an olefin comprising the step of mass-reacting an olefin in the presence of the catalyst system.

Hereinafter, a ligand compound, a chromium complex, a catalyst system for olefin oligomerization, and an oligomerization method of an olefin using the same will be described in detail.

Prior to that, and unless explicitly stated throughout the present specification, the terminology is used merely to refer to a specific embodiment and is not intended to limit the present invention.

And, the singular forms used herein include plural forms unless the phrases expressly have the opposite meaning.

Also, as used herein, the term " comprises " embodies certain features, areas, integers, steps, operations, elements and / or components, It does not exclude the existence or addition of a group.

Herein, the term "catalyst system" means a catalyst system in which three components including a chromium source, a ligand compound, and a cocatalyst, or alternatively, two components of a chromium complex and a cocatalyst are added simultaneously or in any order, &Lt; / RTI > of the catalyst composition. The three or two components of the catalyst system may be added in the presence or absence of a solvent and a monomer, and may be used in a supported or non-supported state.

I. Ligand Compound

According to one embodiment of the invention, there is provided a ligand compound represented by the following formula (1): < EMI ID =

[Chemical Formula 1]

In Formula 1,

N is nitrogen;

B is phosphorus (P), arsenic (As) or antimony (Sb);

As a result of continuous research by the present inventors, it has been confirmed that when the ligand compound represented by the above formula (1) is applied to a catalyst system for oligomerization of olefins, it can exhibit improved 1-hexene selectivity and catalytic activity.

Since the ligand compound has substituent groups introduced into at least one of R ¹ to R ⁴ , at least one of R ⁵ to R ⁹ , or at least one of R ¹⁰ to R ¹⁴ in the formula 1, To show the electronic effect and steric effect of the remarkable difference. Due to these properties, in particular the ligand compounds can exhibit high 1-hexene selectivity as well as high catalytic activity under low olefin pressures.

In the above formula (1), B is phosphorus (P), arsenic (As) or antimony (Sb), preferably phosphorus (P).

In Formula 1, R ¹ to R ¹⁴ are each independently hydrogen, a hydrocarbyl group having 1 to 10 carbon atoms, or a heterohydrocarbyl group; At least one of R ¹ to R ⁴ , at least one of R ⁵ to R ⁹ , or at least one of R ¹⁰ to R ¹⁴ is independently a hydrocarbyl group or a heterohydrocarbyl group having 1 to 10 carbon atoms, or R ⁹ and R ¹⁰ are connected to form a single bond and the remaining group is hydrogen.

Preferably, at least one of R ¹ to R ⁴ , at least one of R ⁵ to R ⁹ , or at least one of R ¹⁰ to R ¹⁴ is independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms , A substituted or unsubstituted cycloalkyl group having 4 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, a substituted or unsubstituted arylalkyl group having 7 to 10 carbon atoms, or a substituted or unsubstituted C1- Lt; / RTI > Here, at least one hydrogen contained in the alkyl group, cycloalkyl group, aryl group, arylalkyl group, and alkoxy group may be substituted with an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a halogen atom, or a cyano group .

Preferably, each of R ¹ to R ⁴ may be hydrogen; At least one of R ⁵ to R ⁹ and at least one of R ¹⁰ to R ¹⁴ is independently selected from the group consisting of methyl, ethyl, propyl, propenyl, propynyl, But are not limited to, butyl, trifluoromethyl, cyclohexyl, 2-methylcyclohexyl, 2-ethylcyclohexyl, 2-isopropylcyclohexyl, 2- isopropylcyclohexyl, benzyl, phenyl, tolyl, xylyl, o-methylphenyl, o-ethylphenyl, o-isopropylphenyl o isopropylphenyl, ot-butylphenyl, o-methoxyphenyl, o-isopropoxyphenyl, cumyl, mesityl, biphenyl for example, biphenyl, naphthyl, anthracenyl, methoxy, ethoxy, phenoxy, tolyloxy, dimethylamino, thiomethyl, ), Or a trimethylsilyl group.

The ligand compounds may be represented by the following examples:

;

;

;

;

;

;

;

;

;

;

;

;

;

;

;

;

;

;

.

In addition to the representative examples, the ligand compound may have various structures within the above-mentioned range.

The ligand compound can be synthesized according to the following scheme, for example.

[Scheme]

In this scheme, X is halogen, Et ₃ N is triethylamine, and THF is tetrahydrofuran.

A more detailed synthesis method for the ligand compound is described in the Example section.

II. Complex

On the other hand, according to another embodiment of the present invention, a complex compound in which a chromium compound is coordinated to the above-mentioned ligand compound is provided.

The complex compound is a complex compound of the above-mentioned ligand compound, and the ligand compound and the chromium (Cr) of the chromium source may have coordination bond.

As a non-limiting example, the complex may be represented by the following formula:

(2)

In Formula 2,

N is nitrogen;

B is phosphorus (P), arsenic (As) or antimony (Sb);

R ¹ to R ¹⁴ are each independently hydrogen, a hydrocarbyl group or a heterohydrocarbyl group having 1 to 10 carbon atoms; At least one of R ¹ to R ⁴ , at least one of R ⁵ to R ⁹ , or at least one of R ¹⁰ to R ¹⁴ is independently a hydrocarbyl group or a heterohydrocarbyl group having 1 to 10 carbon atoms, or R ⁹ and R ¹⁰ are connected to form a single bond and the remaining group is hydrogen;

Cr is chrome;

Y ¹ to Y ³ are each independently halogen, hydrogen, oxygen, or a hydrocarbyl group having 1 to 10 carbon atoms.

Such chromium complexes can be synthesized by a conventional method for preparing the ligand compound.

The complex may be applied to a catalyst system for oligomerization of olefins to exhibit improved 1-hexene selectivity and catalytic activity.

III. Olefin For oligomerization Catalyst system

According to another embodiment of the invention,

i) a chromium source, the ligand compounds and cocatalysts described above; or

ii) the above-described complex and co-catalyst

&Lt; RTI ID = 0.0 > a < / RTI > catalyst system for olefin oligomerization.

That is, the catalyst system for olefin oligomerization comprises i) a three-component catalyst system comprising a chromium source, the ligand compound and cocatalyst described above; Or ii) a two-component catalyst system comprising the complex and the cocatalyst described above.

In the catalyst system, the chromium source may be an organic or inorganic chromium compound having an oxidation state of chromium of 0 to 6, for example, a chromium metal, or a compound in which any organic or inorganic radical is bonded to chromium. Here, the organic radical may be alkyl, alkoxy, ester, ketone, amido radical having 1 to 20 carbon atoms per radical, and the inorganic radical may be a halide, sulfate, oxide, or the like.

Preferably, the chromium source is selected from the group consisting of chromium (III) acetylacetonate, chromium (III) chloride tetrahydrofuran, chromium (III) 2 At least one compound selected from the group consisting of ethyl hexanoate, chromium (III) acetate, chromium (III) butyrate, chromium (III) pentanoate, chromium (III) laurate, and chromium (III) .

The cocatalyst included in the catalyst system may be any organometallic compound capable of activating the main compound contained in the catalyst system. Preferably, the promoter is an organometallic compound containing a Group 13 metal, and is not particularly limited as long as it can be used in the polymerization of an olefin under the catalyst of a transition metal compound.

For example, the cocatalyst may be at least one compound selected from the group consisting of compounds represented by the following formulas (3) to (5):

(3)

^{- [Al (R 31) -O} ] c -

In Formula 3, R ³¹ are the same or different from each other and each independently represents a halogen radical, a hydrocarbyl radical having 1 to 20 carbon atoms, or a hydrocarbyl radical having 1 to 20 carbon atoms substituted with halogen, c is an integer of 2 or more ,

[Chemical Formula 4]

D (R < ⁴¹ ^> ) ₃

In Formula 4, D is aluminum or boron, R ⁴¹ is hydrocarbyl having 1 to 20 carbon atoms or hydrocarbyl having 1 to 20 carbon atoms substituted with halogen,

[Chemical Formula 5]

[LH] ⁺ [Q (E) ₄ ] ^-

In Formula 5,

L is a neutral Lewis base, [LH] ⁺ is a Bronsted acid, Q is boron or aluminum in a +3 type oxidation state, and E is independently at each occurrence one or more hydrogen atoms are replaced by halogen, hydrocarbyl having 1 to 20 carbon atoms, An aryl group having 6 to 20 carbon atoms or an alkyl group having 1 to 20 carbon atoms which is substituted or unsubstituted with an alkoxy functional group or a phenoxy functional group.

According to one embodiment, the compound represented by Formula 3 may be an alkylaluminoxane such as methylaluminoxane, ethylaluminoxane, isobutylaluminoxane, or butylaluminoxane. Further, it may be a modified alkylaluminoxane (MMAO) in which two or more alkylaluminoxanes are mixed.

According to one embodiment, the compound represented by Formula 4 may be selected from the group consisting of trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylchloroaluminum, dimethylisobutylaluminum, dimethylethylaluminum, di But are not limited to, ethyl chloro aluminum, triisopropyl aluminum, triisobutyl aluminum, tri-s-butyl aluminum, tricyclopentyl aluminum, tripentyl aluminum, triisopentyl aluminum, trihexyl aluminum, ethyl dimethyl aluminum, Aluminum, tri-p-tolyl aluminum, dimethyl aluminum methoxide, dimethyl aluminum ethoxide, trimethyl boron, triethyl boron, triisobutyl boron, tripropyl boron, tributyl boron and the like.

Also, according to one embodiment, the compound represented by the general formula (5) is at least one selected from the group consisting of triethylammonium tetraphenylboron, tributylammonium tetraphenylboron, trimethylammonium tetraphenylboron, tripropylammonium tetraphenylboron, trimethylammonium (O, p-dimethylphenyl) boron, triethylammoniumtetra (p-tolyl) boron, triethylammoniumtetra (P-trifluoromethylphenyl) boron, butylammoniumtetra (p-trifluoromethylphenyl) boron, trimethylammoniumtetra (p -trifluoromethylphenyl) boron, tributylammonium tetrapentafluorophenylboron, N, N-diethylanilinium tetraphenyl Boron, N, N-diethylanilinium tetraphenylboron, N, N-diethylanilinium tetrapentafluorophenylboron, diethylammonium tetrapentafluorophenylboron, triphenylphosphonium tetraphenylboron,Trimethylammonium tetraphenyl aluminum, trimethylammonium tetraphenyl aluminum, trimethylammonium tetraphenyl aluminum, trimethylammonium tetraphenyl aluminum, trimethylammonium tetraphenyl aluminum, trimethylammonium tetraphenyl aluminum, (P-tolyl) aluminum, triethylammoniumtetra (o, p-dimethylphenyl) aluminum, tributylammoniumtetra (ptrifluoromethylphenyl) aluminum, trimethylammoniumtetra Fluoromethylphenyl) aluminum, tributylammonium tetrapentafluorophenyl aluminum, N, N-diethylanilinium tetraphenyl aluminum, N, N-diethylanilinium tetraphenyl aluminum, N, N-diethylaniline Aluminum tetraphenylphosphonium aluminum, diethylammonium tetrapentafluorophenyl aluminum, triphenylphosphonium tetraphenyl aluminum, trimethylphenyl aluminum Boron tetraphenylboron, triphenylboronium tetraphenylboron, triphenylboronium tetraphenylboron, triphenylboronium tetraphenylboron, triphenylboronium tetraphenylboron, triphenylboronium tetraphenylboron, triphenylboronium tetraphenylboron, triphenylboronium tetraphenylboron, And the like.

The promoter may be an organoaluminum compound, an organoboron compound, an organomagnesium compound, an organozinc compound, an organolithium compound, or a mixture thereof.

For example, the promoter is preferably an organoaluminum compound, more preferably trimethyl aluminum, triethyl aluminum, triisopropyl aluminum, triisobutyl aluminum, ), Ethylaluminum sesquichloride, diethylaluminum chloride, ethyl aluminum dichloride, methylaluminoxane, and modified methylaluminoxane), and the like. Lt; / RTI > group.

On the other hand, the content ratio of the components constituting the catalyst system can be determined in consideration of catalytic activity and selectivity to linear alpha-olefins. In one embodiment, the molar ratio of the ligand compound: chromium source: cocatalyst is about 1: 1: 1 to 10: 1: 10,000, or about 1: 1: 100 to 5: 1 : 3,000. In the case of the two-component catalyst system, it is advantageous that the molar ratio of the complex compound to the co-catalyst is controlled to be 1: 1 to 1: 10,000, or 1: 1 to 1: 5,000, or 1: 1 to 1: 3,000.

In addition, the catalyst system may further include a carrier. That is, the ligand compound and the complex compound can be applied to ethylene oligomerization in a form supported on a carrier. The carrier may be a metal, a metal salt, a metal oxide, or the like, which is applied to a conventional supported catalyst. Non-limiting examples of the carriers include silica, silica-alumina, silica-may be magnesia or the _{like, Na 2 O, K 2 CO} 3, BaSO 4, Mg (NO 3) 2 oxides of metals, such as carbonates, sulfates, be May contain a trichromatic component.

The components constituting the catalyst system can be added simultaneously or in any order, in the presence or absence of a suitable solvent and a monomer, to function as a catalyst system having activity. At this time, suitable solvents include heptane, toluene, diethyl ether, tetrahydrofuran, acetonitrile, dichloromethane, chloroform, chlorobenzene, methanol, acetone and the like.

IV. Olefinic Oligomerization Way

On the other hand, according to another embodiment of the present invention, there is provided a method for oligomerization of an olefin comprising the step of mass-reacting an olefin in the presence of the above-mentioned catalyst system.

The method of oligomerization of olefins according to the present invention can be carried out by applying an olefin (for example, ethylene) as a raw material to the above-described catalyst system, conventional apparatus and contact technique. As a non-limiting example, the oligomerization reaction of the olefin may be carried out in the presence of a homogeneous liquid phase reaction in the presence or absence of an inert solvent, or a slurry reaction in which the catalyst system is partially or completely dissolved, or the product alpha- Or a gaseous reaction.

The oligomerization reaction of the olefin may be carried out in an inert solvent. By way of non-limiting example, the inert solvent may be benzene, toluene, xylene, cumene, heptane, cyclohexane, methylcyclohexane, methylcyclopentane, n-hexane, 1-hexene, 1-octene, and the like.

The oligomerization reaction of the olefin may be carried out at a temperature of about 0 to 200 ° C, or about 0 to 150 ° C, or about 30 to 100 ° C, or about 50 to 100 ° C. The reaction may also be carried out under a pressure of from about 1 to 300 bar or from 2 to 150 bar.

The ligand compounds and complexes according to the present invention can be included in a catalyst system for olefin oligomerization to exhibit improved 1-hexene selectivity and catalytic activity.

1 is an NMR spectrum of a ligand compound according to Synthesis Example 1. Fig.
2 is an NMR spectrum of a ligand compound according to Synthesis Example 2. Fig.
3 is an NMR spectrum of a ligand compound according to a control example.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. However, the following embodiments are intended to illustrate the invention, but the invention is not limited thereto.

Synthetic example One

Pyrrole (20 mmol), triethylamine (20 mmol), and tetrahydrofuran (5 mL) were placed in a Schlenk flask and chlorodi- p- toluylphosphine (4.6 mmol) was added dropwise at 0 ° C. The reaction was stirred for 30 minutes at 0 ° C, then the temperature was increased to room temperature and the reaction was further continued for 30 minutes. Thereafter, they were reacted with reflux for 15 hours.

The resulting precipitate was filtered off with THF and the filtrate was dried under vacuum. After drying the filter, and rinsed and the resulting oil with hexane, purified by column chromatography to give 1- (di-p-tolylphosphino) -1 H -pyrrole. ¹ H NMR (CDCl ₃ ) spectrum and ³¹ P NMR (CDCl ₃ ) spectrum of the compound are shown in FIG.

Synthetic example 2

chlorodi- p -tolylphosphine place of bis (3,5-bis (trifluoromethyl) phenyl) except for using the chlorophosphine and 1 in the same manner as in Synthesis Example 1 (bis (3,5-bis ( trifluoromethyl) phenyl) phosphino) - 1 H -pyrrole. The ¹ H NMR (CDCl ₃ ) spectrum and ³¹ P NMR (CDCl ₃ ) spectrum of the compound are shown in FIG.

Control Example

except that instead of diphenylphosphine chlorodi- p -tolylphosphine, and in the same manner as in Synthesis Example 1 1- (diphenylphosphino) -1 H -pyrrole was obtained a. The ¹ H NMR (CDCl ₃ ) spectrum and the ³¹ P NMR (CDCl ₃ ) spectrum of the compound are shown in FIG.

Manufacturing example One

A 125 mL Parr reactor equipped with a pressure controller was prepared. Methylcyclohexane (47 mL) and aluminum cocatalyst were added to the reactor. After saturation with nitrogen gas, the solution was stirred for 15 minutes.

A catalyst solution containing chromium (III) acetylacetonate (0.01 mmol), the ligand according to Synthesis Example 1 (0.02 mmol) and methylcyclohexane (3 mL) was prepared.

The time when the catalyst solution was injected with the ethylene gas into the reactor was regarded as a time zero. After 30 minutes, the reaction was terminated by stopping the ethylene feed and cooling the reactor (below 5 占 폚).

After excess ethylene was vented from the reactor, nonane (1 mL) was added as an internal standard for GC-FID analysis of the liquid phase. A small amount of the reaction solution was sampled to confirm the distribution of oligomers by GC-FID analysis. The mixture of methanol and diluted HCl was added to the remaining reaction solution and stirred to analyze the amount of the solid.

Manufacturing example 2 to 6

As shown in the following Tables 1 and 2, except that the ligand according to Synthesis Example 2 or the control example was used instead of the ligand according to Synthesis Example 1, and the ratio of the cocatalyst and the pressure of ethylene were adjusted, The oligomerization reaction of ethylene was carried out.

Production Example 1 Production Example 2 Production Example 3 Ligand Synthesis Example 1 Synthesis Example 2 Control Example Co-catalyst
(DMAO eq / TiBAl eq to Cr) 500/50 500/50 500/50 Ethylene pressure (bar) 10 10 10 Catalytic activity (g / g Cr / hr) 214.1 582.7 232.2 Olefin
in liquid
(wt%) 1-C ₆ 94.7 96.3 88.3 1-C ₈ 2.4 0.8 3.2 C ₁₀ to C ₄₀ 1.5 0.5 1.0 Solid (wt%) 14.4 6.2 13.7

Production Example 4 Production Example 5 Production Example 6 Ligand Synthesis Example 2 Synthesis Example 2 Synthesis Example 2 Co-catalyst
(DMAO eq / TiBAl eq to Cr) 500/50 500/100 100/500 Ethylene pressure (bar) 20 20 20 Catalytic activity (g / g Cr / hr) 1550 2200 1937 Olefin
in liquid
(wt%) 1-C ₆ 99.0 99.1 98.7 1-C ₈ 0.5 0.4 0.5 C ₁₀ to C ₄₀ 0.4 0.4 0.4 Solid (wt%) 4.8 3.2 1.8

Referring to Tables 1 and 2, Production Example 1 in which the compound of Synthesis Example 1 was applied as a ligand exhibited an equivalent degree of catalytic activity as compared with Production Example 3 in which the compound of the comparative example was applied as a ligand, Respectively.

Particularly, in the case of Production Example 2, the catalyst activity and the 1-hexene selectivity were improved more than twice as compared with Production Example 3. In addition, in Examples 4 to 6, it was confirmed that the catalyst activity and the 1-hexene selectivity were remarkably improved by increasing the pressure of ethylene and changing the composition of the co-catalyst.

Claims

A ligand compound represented by the following formula (1):
[Chemical Formula 1]

In Formula 1,
N is nitrogen;
B is phosphorus (P), arsenic (As) or antimony (Sb);
R ¹ to R ¹⁴ are each independently hydrogen, a hydrocarbyl group having 1 to 10 carbon atoms or a heterohydrocarbyl group,
At least one of R ¹ to R ⁴ , at least one of R ⁵ to R ⁹ , or at least one of R ¹⁰ to R ¹⁴ is independently a hydrocarbyl group or a heterohydrocarbyl group having 1 to 10 carbon atoms, or
R ⁹ and R ¹⁰ are connected to form a single bond and the remaining group is hydrogen.

The method according to claim 1,
Wherein B is phosphorus (P) and R ¹ to R ⁴ are each hydrogen.

The method according to claim 1,
At least one of R ¹ to R ⁴ , at least one of R ⁵ to R ⁹ , or at least one of R ¹⁰ to R ¹⁴ is independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, A substituted or unsubstituted aryl group having 6 to 10 carbon atoms, a substituted or unsubstituted arylalkyl group having 7 to 10 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms. Ligand compound.

A complex compound in which a chromium compound is coordinated to the ligand compound according to claim 1.

i) a chromium source, a ligand compound according to claim 1 and a cocatalyst; or
ii) a complex according to claim 4 and a promoter
&Lt; / RTI >

6. The method of claim 5,
The chromium source may be selected from the group consisting of chromium (III) acetylacetonate, chromium (III) chloride tetrahydrofuran, chromium (III) 2- ethylhexanoate, chromium (III) acetate, chromium (III) Octylate, chromium (III) laurate, and chromium (III) stearate.

6. The method of claim 5,
The cocatalyst may be selected from the group consisting of trimethyl aluminum, triethyl aluminum, triisopropyl aluminum, triisobutyl aluminum, ethylaluminum sesquichloride, diethyl aluminum Wherein the catalyst is at least one compound selected from the group consisting of diethylaluminum chloride, ethyl aluminum dichloride, methylaluminoxane, and modified methylaluminoxane.

A process for the oligomerization of olefins comprising reacting the olefins in the presence of a catalyst system according to claim 5.

9. The method of claim 8,
Wherein said step is carried out at a temperature of from 0 to 200 < 0 > C and a pressure of from 1 to 300 bar.

9. The method of claim 8,
Wherein said olefin is ethylene.