KR20160086511A - Chromium compound, catalyst system comprising the same, and ethylene trimerization method using the thereof - Google Patents

Abstract

Embodiments of the present invention relate to a chromium compound represented by chemical formula 1, [{CH_3(CH_2)_3CH(CH_2CH_3)CO_2}_2Cr(OH)]_4·2H_2O, and relate to a catalyst system comprising the same. The embodiments have excellent catalytic activities in a trimerization reaction of olefin.

Description

TECHNICAL FIELD [0001] The present invention relates to a chromium compound, a catalyst system containing the chromium compound, and an ethylene trimerization method using the same. BACKGROUND ART < RTI ID = 0.0 >

Embodiments of the present invention relate to a chromium compound, a catalytic system comprising the same, and a process for ethylene trimerization using the same.

As a catalyst system for producing 1-hexene or the like by trimerization of olefins such as ethylene, a catalyst comprising chromium (III) compounds, pyrrole compounds, non-hydrolyzed aluminum alkyls and unsaturated hydrocarbons ), A highly active, highly selective ethylene trimerization catalyst system was disclosed by Philips in 1994 (U.S. Patent No. 5,376,612). Since then, commercial production of 1-hexene has been started in 2003 based on the catalyst system. Catalytic systems using tris (2-ethylhexanoate) chromium (III) (Cr (EH) ₃ , EH = O ₂ C ₈ H ₁₅ ) in various chromium trivalent compounds showed particularly good catalytic activity and Cr EH) ₃ was intensively studied and commercialized.

The catalyst system using Cr (EH) ₃ can be prepared by, for example, adding a mixed solution of triethylaluminum and ethylaluminum dichloride to an aromatic hydrocarbon solvent (toluene etc.) in which Cr (EH) ₃ and 2,5- In an aromatic hydrocarbon solvent. Since the trimerization reaction of olefins is usually carried out in an aliphatic hydrocarbon solvent such as cyclohexane, the aromatic hydrocarbon solvent of the prepared catalyst system is removed by vacuum decompression and then re-dissolved in an aliphatic hydrocarbon solvent such as cyclohexane, After the completion of the reaction, the aromatic hydrocarbon solvent used for preparing the catalyst should be separated and removed. Further, in the production of a catalyst using Cr (EH) ₃ , a black precipitate is formed as a byproduct as a catalyst activating species is formed, and therefore, a process for removing the black precipitate by filtration is required (see U.S. Patent No. 5,563,312). Such an aromatic hydrocarbon solvent removing step such as toluene, a filtration step and the like may be burdened in commercialization. When the catalyst system is produced in an aliphatic hydrocarbon solvent such as cyclohexane in which the trimerization reaction is performed in order to omit the step of removing the aromatic hydrocarbon solvent, the thermal stability of the produced catalyst is lowered, (See U.S. Patent No. 5,563,312). In the catalyst system of Phillips, etc., an unsaturated hydrocarbon is included as an essential component.

Therefore, there is a need to develop a raw material compound of a catalyst system capable of producing a catalyst system in an aliphatic hydrocarbon solvent, and a catalyst system having excellent catalytic activity in ethylene trimerization, since no byproduct is produced during the production of the catalyst, .

An object of the present invention is to provide a chromium compound having a novel structure.

Another object of the present invention is to provide a catalyst system comprising the chromium compound, wherein the catalyst preparation process is simple and has excellent catalytic activity in the ethylene trimerization reaction.

Another object of the present invention is to provide an ethylene trimerization reaction using the above catalyst system.

The above and other objects of the present invention can be achieved by the present invention described below.

An embodiment of the present invention relates to a chromium compound represented by the following formula (1).

[Chemical Formula 1]

[{CH ₃ (CH ₂ ) ₃ CH (CH ₂ CH ₃ ) CO ₂ } ₂ Cr (OH)] ₄ .2H ₂ O

Another embodiment of the present invention relates to a catalyst system comprising a chromium compound represented by the following general formula (1).

The catalyst system of one embodiment comprises: a chromium compound represented by the following formula (1); An aluminum compound represented by the following formula (3); And a pyrrole compound represented by Formula 4 below; ≪ / RTI >

The catalyst system of another embodiment is a chromium compound represented by the following formula (1): ???????? An aluminum compound represented by the following formula (3); And an alumino-pyrrole compound represented by the following formula (5); ≪ / RTI >

[Chemical Formula 1]

[{CH ₃ (CH ₂ ) ₃ CH (CH ₂ CH ₃ ) CO ₂ } ₂ Cr (OH)] ₄ .2H ₂ O

(3)

(R ² ) _n Al (X ² ) _3-n

In Formula 3, R ² is a hydrocarbon group having 1 to 20 carbon atoms, X ² is a halogen atom, and the average value of n is 1 to 3;

[Chemical Formula 4]

In Formula 4, R ³ , R ⁴ , R ^5, and R ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms;

[Chemical Formula 5]

Wherein R ² is a hydrocarbon group having 1 to 20 carbon atoms and R ³ , R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

The aluminum compound of Formula 3 may be a mixture of triethylaluminum (Et ₃ Al) and diethylaluminum chloride (Et ₂ AlCl).

The pyrrole compound of Formula 4 may be 2,5-dimethylpyrrole.

In Formula 5, R ³ and R ⁶ may be methyl, R ⁴ and R ⁵ may be hydrogen, and R ² may be ethyl.

 The catalyst system may have a molar ratio (Cr: Al) of the chromium compound and the aluminum compound introduced at the time of preparation (reaction) from 1:10 to 1:50.

 In the catalyst system, the molar ratio of the chromium compound and the pyrrole compound (chromium compound: pyrrole compound) to be added during the production (reaction) may be 1: 1 to 1: 5.

The catalyst system may further include an aliphatic hydrocarbon solvent.

Another embodiment of the catalyst system comprises a catalyst precursor represented by the following formula (2); And an aluminum compound represented by Formula 3; ≪ / RTI >

(2)

Wherein R ² is a hydrocarbon group having 1 to 20 carbon atoms, X is R ² or a halogen atom, R ³ , R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms to be.

In Formula 2, R ² is methyl or ethyl, X is R ² or a chlorine atom, R ³ and R ⁶ are methyl, and R ⁴ and R ⁵ are hydrogen atoms.

Another embodiment of the present invention relates to a catalyst precursor represented by the following general formula (2).

(2)

Wherein R ² is a hydrocarbon group having 1 to 20 carbon atoms, X is R ² or a halogen atom, R ³ , R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms to be.

Another embodiment of the present invention relates to an olefin polymerization process comprising contacting an olefin polymer having a carbon number of 2 to 10 with a catalyst system comprising the above-mentioned chromium compound to prepare an olefin polymer.

The olefin monomer may be ethylene, and the olefin polymer may be an olefin trimer.

The embodiments of the present invention have the effect of the invention of providing a chromium compound having a novel structure. Further, the present invention has the effect of providing a catalyst system comprising the chromium compound and a method for producing 1-hexene using the catalyst system, wherein the catalyst preparation process is simple and excellent in catalytic activity in the ethylene trimerization reaction.

1 is an IR spectrum of a chromium compound prepared according to Production Example 1 of the present invention.
2 shows the structure revealed by single crystal X-ray diffraction analysis of the catalyst precursor prepared according to Production Example 4 of the present invention.
FIG. 3 shows the structure revealed by single crystal X-ray diffraction analysis of the catalyst precursor prepared according to Production Example 5 of the present invention.
4 shows the result of single crystal X-ray diffraction analysis of the intermediate compound obtained in the catalyst system prepared in Example 3 of the present invention.
5 is a photograph of a catalyst system manufactured according to Embodiment 2 of the present invention.
6 is a photograph before filtration of a catalyst system manufactured according to Comparative Example 1 of the present invention.

Hereinafter, the present invention will be described in detail.

One embodiment of the present invention relates to a chromium compound represented by the following formula (hereinafter referred to as " chromium compound ").

[Chemical Formula 1]

[{CH ₃ (CH ₂ ) ₃ CH (CH ₂ CH ₃ ) CO ₂ } ₂ Cr (OH)] ₄ .2H ₂ O

The chromium compound forms a structure in which four molecules of {CH ₃ (CH ₂ ) ₃ CH (CH ₂ CH ₃ ) CO ₂ } ₂ Cr (OH) compound and two molecules of water are combined as shown in Formula 1, When used in a catalyst system for polymerization, the catalytic activity for the ethylene trimerization reaction is excellent.

The chromium compound of one embodiment is obtained by, for example, reacting an aqueous solution of a chromium trivalent salt compound represented by the following formula (6) and an aqueous solution of an alkali metal salt of 2-ethylhexanoic acid represented by the following formula (7) Quot; production reaction ").

[Chemical Formula 6]

Cr (X ¹ ) ₃

In Formula 6, X ¹ is a halogen atom, NO ₃ (nitrate ion), or ClO ₄ (perchlorate ion). Examples of the halogen atom include a chlorine atom (Cl), an iodine atom (I), a fluorine atom (F), and a bromine atom (Br).

Specifically, chrome trivalent salt compound represented by formula (6) is chloride, chromium (CrCl _3), its hydrate _{(CrCl 3 · 6H 2 O)} , nitric acid, chromium _{(Cr (NO 3) 3)} , its hydrate (Cr (NO ₃ ) ₃ .9H ₂ O), chromium perchlorate (Cr (ClO ₄ ) ₃ ), hydrate thereof (Cr (ClO ₄ ) ₃ .6H ₂ O), and the like. In one embodiment, chromium 3 is used as a salt compound with a hydrate (for example, CrCl ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .9H ₂ O, Cr (ClO ₄ ) ₃ .6H ₂ O, etc.) , The solubility in water is high so that the reactivity can be improved and the economical efficiency can be excellent.

(7)

{CH ₃ (CH ₂ ) ₃ CH (CH ₂ CH ₃ ) CO ₂ } M

In the above formula (7), M is an alkali metal, and examples of the alkali metal include sodium (Na), potassium (K), and lithium (Li). The alkali metal salt of formula (7) can be easily obtained, for example, by reacting 2-ethylhexanoic acid with an alkali metal hydroxide (NaOH, KOH, LiOH, etc.) in water in equivalent amounts.

The reaction for preparing the chromium compound (reaction of an aqueous solution of a chromium trivalent salt compound and an aqueous solution of an alkali metal salt of 2-ethylhexanoate) is carried out at a reaction temperature of 20 to 100 캜, for example, 50 to 100 캜, Lt; 0 > C to 95 < 0 > C. In the above reaction, the equivalent ratio of the alkali metal salt of 2-ethylhexanoic acid to 1 equivalent of the chromium trivalent salt compound is 1: 3 to 1: 4, specifically 1: 3 to 1: 3.5 or 1: 1: 3.2. Within this range, chromium compounds can be obtained in high yield.

When the chromium compound production reaction is carried out within the range of the temperature and the equivalence ratio, one equivalent of 2-ethylhexanoic acid, which is a by-product, can be produced.

The reaction for preparing the chromium compound may be carried out by further containing a hydrocarbon solvent (methylcyclohexane, mineral spirit, etc.). The chromium compound and 2-ethylhexanoic acid prepared by the above reaction have low solubility in water, but high solubility in hydrocarbon solvent. Therefore, when a hydrocarbon solvent is further added during the reaction for producing the chromium compound, the chromium compound and the by-product, 2-ethylhexanooxy acid, which are produced by the addition of the hydrocarbon solvent, are dissolved in the hydrocarbon solvent layer, and the other by- Purification may be easy. For example, when a hydrocarbon solvent is further added, a hydrocarbon solvent layer may be recovered after the reaction for preparing the chromium compound, followed by washing with a basic aqueous solution to remove the by-product, 2-ethylhexanoic acid, as an aqueous solution layer. In this way, the chromium compound can be easily obtained in the form of a solution in a hydrocarbon solvent. The thus obtained solution can be used as it is in the production of the catalyst system, and in some cases, the solvent may be distilled off and used as a powder phase.

The hydrocarbon solvent may be, for example, an aliphatic hydrocarbon solvent having 4 to 20 carbon atoms, an aromatic hydrocarbon solvent having 6 to 20 carbon atoms, or a mixture thereof. Specific examples of the aliphatic hydrocarbon solvent include isobutane, pentane, hexane, heptane, octane, nonane, decane, cyclohexane and methylcyclohexane. Examples of the aromatic hydrocarbon solvent include benzene, toluene, xylene, Mesitylene, ethylbenzene, cumene, and the like.

The chromium compound prepared by the above method can be demonstrated by observing an OH stretching signal of 3,630 cm ^-1 in the IR spectrum. Further, it is possible to further demonstrate the production of a chromium compound having the composition represented by the above formula (1) by measuring the mass of the obtained chromium compound and the mass of 1 equivalent of 2-ethylhexanoic acid produced as a by-product relative to the mass of the charged chromium trivalent salt compound have.

In one embodiment, when a chromium compound is prepared by using chromium chloride (CrCl ₃ ) as a salt compound, the amount of chloride ion (Cl ^- ) remaining in the aqueous solution layer is titrated with silver nitrate (AgNO ₃ ) , It can be proved that the chromium compound prepared from the neutralization of the acidity of the aqueous solution layer is composed of the basic composition of {CH ₃ (CH ₂ ) ₃ CH (CH ₂ CH ₃ ) CO ₂ } ₂ Cr (OH) .

In addition, the chromium compound prepared by the above _{method, {CH 3 (CH 2)} 3 CH (CH 2 CH 3) CO 2} 2 Cr (OH) molecules four dogs [{CH in the formula (1) to two molecules of water dog copolymer ₃ (CH ₂ ) ₃ CH (CH ₂ CH ₃ ) CO ₂ } ₂ Cr (OH)] ₄ · 2H ₂ O is the molecular weight and elemental analysis data calculated by measuring the freezing point in benzene .

In one embodiment, the structure of the chromium compound may be of the formula (I)

[Formula 1a]

In the above formula (I), R ¹ is CH ₃ (CH ₂ ) ₃ CH (CH ₂ CH ₃ ) -. The chromium compound of Formula 1a has an adamantane type structure. The chromene compound of the adamantane structure can be obtained, for example, by a structural analysis of a single crystal of an intermediate compound precipitated partially from the catalyst solution prepared in Example 3 described below by X-ray diffraction, (Fig. 4).

The _{[{CH 3 (CH 2)} 3 CH (CH 2 CH 3) CO 2} 2 Cr (OH)] 4 · when the chromium compounds of the 2H ₂ O having an Ada-Men retain the structure of formula (1a) form, the stable form . In this case, the reliability of the chromium compound is high, making it efficient and economical. Also, by having the above structure, the solubility is high, and when it is dissolved, viscosity is low, and handling and uniformity of reaction are excellent. The structural stability of the compound containing two water molecules is determined by dissolving the two molecules of water coordinated in the chromium compound of formula (1) in xylene and then refluxing at 160 DEG C for 10 hours using a Dean- The water molecule can not be removed at all. Also, it was confirmed that there was no change in molecular weight calculated by measuring IR spectrum, elemental analysis data and freezing point of benzene before and after the dehydration reaction. In the case of Cr (EH) ₃ used in the conventional Phillips catalyst production, its composition varies depending on the preparation of the compound, and there is a problem in reliability and reproducibility in the preparation of the catalyst. However, since the chromium compound of the formula (1) It is easy to ensure reproducibility and reliability in the preparation of compounds and catalysts.

Compounds of the type consisting of four molecules of chromium compound and two molecules of water of Formula 1 were unique and unique when chromium compounds were prepared using 2-ethylhexanoic acid.

Another embodiment of the present invention relates to a catalyst system comprising the chromium compound represented by Formula 1 above. The catalyst system comprises an aluminum compound and a pyrrole compound; Or aluminum compounds and alumino-pyrrole compounds; May be included together with the chromium compound. These catalyst systems are highly active when used in olefin polymerization.

The catalyst system of one embodiment includes the chromium compound represented by Formula 1; An aluminum compound represented by the following formula (3); And a pyrrole compound represented by Formula 4 below; ≪ / RTI > Such a catalyst system does not require a filtration step since a precipitate is not produced in the production of the catalyst, and thus the catalyst is easily produced. Further, such a catalyst system is very useful in the ethylene trimerization reaction.

The catalyst system of another embodiment is a chromium compound represented by the above formula (1); An aluminum compound represented by the following formula (3); And an alumino-pyrrole compound represented by the following formula (5). Such a catalyst system is very useful in the ethylene trimerization reaction, and is also useful because it is possible to prepare a catalyst in an aliphatic hydrocarbon solvent.

In the catalyst system, the chromium compound is the same as the chromium compound represented by the above-mentioned formula (1). When the chromium compound of Formula 1 is used, the catalyst is easily prepared because of its high solubility in aliphatic and aromatic hydrocarbon solvents, and the catalytic activity of the prepared catalyst system is high.

In the catalyst system, the aluminum compound is a compound represented by the following formula (3).

(3)

(R ² ) _n Al (X ² ) _3-n

In the above formula (3), R ² is a hydrocarbon group having 1 to 20 carbon atoms, X ² is a halogen atom, and the average value of n is 1 to 3.

In the general formula (3), the hydrocarbon group may specifically be an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 15 carbon atoms, an alkyl group having 1 to 10 carbon atoms, or an alkyl group having 1 to 5 carbon atoms. The structure of the alkyl group may be, for example, linear, branched or cyclic. More specifically, examples of the hydrocarbon group include a methyl group, an ethyl group, a propyl group, and an isobutyl group.

(I), fluorine atom (F), bromine atom (Br), and the value of n is, for example, 2 to 3 days have.

In an embodiment, the aluminum compound may be a single compound or a mixture of aluminum compounds with different values of n, but is not limited thereto. Specifically, the aluminum compound ((R ² ) ₃ Al) in which n is 3 in Formula 3 and / or the aluminum compound ((R ² ) ₂ Al (X ² )) in which n in Formula 3 is 2 can be used. Among them, triethylaluminum (Et ₃ Al) and diethylaluminum chloride (Et ₂ AlCl) in which R ² is an ethyl group in the above formula (3) are used in large quantities as a promoter of a Ziegler-Natta catalyst in industry, But it is not limited thereto. The (R ² ) ₂ Al (X ² ) can be obtained by reacting the (R ² ) ₃ Al with organic and inorganic materials containing various halogens.

The mixing ratio (molar ratio) of (R ² ) ₃ Al and (R ² ) ₂ Al (X ² ) may be 1: 0.5 to 1: 2, for example, 1: 1.

In one exemplary catalytic system, the aluminum compound of Formula 3 may be a mixture of triethylaluminum (Et ₃ Al) and diethylaluminum chloride (Et ₂ AlCl). In this case, the mixing ratio (molar ratio) of triethylaluminum (Et ₃ Al): diethylaluminum chloride (Et ₂ AlCl) may be 1: 0.5 to 1: 2, for example 1: 1. Within this range, it is possible to increase the reaction efficiency of the catalyst system without remaining excessively unreacted aluminum compounds.

The molar ratio (Cr: Al) of the chromium compound and the aluminum compound introduced in the production (reaction) of the catalyst system is 1: 3 to 1: 100, for example, 1:10 to 1:50, 1:40. Within the above range, the catalyst system can be realized with high activity while improving the economical efficiency. In such a case, 1-hexene as an ethylene trimer can be obtained in high yield and high purity.

In the catalyst system, the aluminum compound reacts with the chromium compound and the pyrrole compound to participate in the activation catalyst species forming reaction, and in addition, some of the water and oxygen included in the solvent and the monomer during the production of the catalyst system or the olefin polymerization (trimerization) The catalyst poison can be removed. The amount of water, oxygen, etc. contained in the solvent and the monomer may vary depending on the case. Therefore, the amount of the aluminum compound to be added may be set to a suitable optimum value depending on each case.

In addition, when the catalyst system is used for olefin polymerization, an aluminum compound may be separately added to the olefin polymerization reaction solvent separately from the catalyst system for removing water, oxygen, and the like. In this case, the amount of the aluminum compound added separately to the olefin polymerization reaction solvent is not included in the above molar ratio.

In the catalyst system of one embodiment, the chromium compound represented by Formula 1; The pyrrole compound to be reacted with the aluminum compound represented by the following formula (3) may be a compound represented by the following formula (4).

[Chemical Formula 4]

In Formula 4, R ³ , R ⁴ , R ^5, and R ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

In Formula 4, the alkyl group may have 1 to 8, 1 to 6, or 1 to 4 carbon atoms, for example, and the structure may be linear, branched or cyclic. Specifically, examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and an isobutyl group.

(Wherein R ³ , R ⁴ , R ⁵ and R ⁶ are hydrogen atoms), R ³ in the formula (4) is a hydrogen atom, and R ⁴ , R ⁵ , and R ⁶ is an alkyl group having 1 to 10 carbon atoms, but the present invention is not limited thereto.

In one embodiment of the catalyst system, the pyrrole compound of Formula 4 may use 2,5-dimethylpyrrole wherein R ³ and R ⁶ are methyl groups. In this case, the unit cost of the raw material is low, and the catalyst system can realize high activity.

In the catalyst system, the molar ratio (chromium compound: pyrrole compound) of the chromium compound and the pyrrole compound (chromium compound: pyrrole compound) to be added during the production (reaction) is in the range of 1: 1 to 1:10, such as 1: 1 to 1: 1 to 1: 3. In the above range, the activity of the catalyst system is excellent, and 1-hexene, which is an ethylene trimer, can be obtained in high yield and high purity.

In the catalyst system of another embodiment, the alumino-pyrrole compound to be reacted together with the chromium compound represented by the formula (1) and the aluminum compound represented by the formula (3) may be a compound represented by the following formula (5).

[Chemical Formula 5]

Wherein R ² is a hydrocarbon group having 1 to 20 carbon atoms and R ³ , R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

In Formula 5, R ² may specifically be a hydrocarbon group, for example, an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 15 carbon atoms, an alkyl group having 1 to 10 carbon atoms, or an alkyl group having 1 to 5 carbon atoms.

In Formula 5, R ³ , R ⁴ , R ^5, and R ⁶ are each independently a hydrogen atom; Or an alkyl group having 1 to 8, 1 to 6 or 1 to 4 carbon atoms, for example.

In Formula 5, the alkyl group may have a linear, branched or cyclic structure. More specifically, examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and an isobutyl group.

In an exemplary embodiment of the catalyst system, the alumino-pyrrole compound of Formula 5 is such that R ³ and R ⁶ are methyl groups, R ⁴ and R ⁵ are hydrogen, and R ² is an ethyl group. When such an alumino-pyrrole compound is used, the activity of the catalyst system is high.

The alumino-pyrrole compound of one embodiment can be obtained by, for example, a method of reacting the pyrrole compound of Formula 4 with (R ² ) ₃ Al; Or a method of forming an N-lithio pyrrole compound by using n-BuLi or the like in the pyrrole compound of Formula 4 and reacting it with (R ² ) ₂ AlCl ₃ ; . In this case, diethyl ether or the like can be used as a reaction solvent, and in such a case, the compound of formula (5) can be obtained as a combined product of aluminum and diethyl ether. Since diethyl ether coordinated to aluminum is easily decarboxylated in the preparation of the catalyst system, the presence or absence of diethyl ether coordination does not significantly affect the activity of the prepared catalyst system.

The catalyst system according to the above embodiments may further include a hydrocarbon solvent. When a hydrocarbon solvent is included, the catalyst system may be present in a homogeneous solution in which the reactant is dissolved in a hydrocarbon solvent.

Also, as described in the background art, the Philips catalyst system is essentially required to have an aromatic hydrocarbon solvent. However, the catalyst system according to the embodiments of the present invention is excellent in solubility in a hydrocarbon solvent and can realize high activity in an aliphatic hydrocarbon solvent. Therefore, the catalyst system can be produced in the aliphatic hydrocarbon solvent in which the ethylene trimerization reaction is carried out, so that the aromatic hydrocarbon solvent removing step and the filtration step can be omitted.

Examples of the hydrocarbon solvent include an aliphatic hydrocarbon solvent having 4 to 20 carbon atoms, an aromatic hydrocarbon solvent having 6 to 20 carbon atoms, a mixture thereof, and the like. Examples of the aliphatic hydrocarbon solvent include isobutane, pentane, hexane, heptane, octane, nonane, decane, cyclohexane and methylcyclohexane. Specific examples of the aromatic hydrocarbon solvent include benzene, toluene, xylene, Tylene, ethylbenzene, cumene, and the like. Since the ethylene trimerization reaction is carried out in an aliphatic hydrocarbon solvent, it is possible to prepare a catalyst system using the same aliphatic hydrocarbon solvent as the solvent used in the ethylene trimerization reaction, in view of separation and purification after the reaction.

The catalyst system of one embodiment can be obtained, for example, by contacting and reacting a chromium compound represented by Formula 1, an aluminum compound represented by Formula 3, and a pyrrole compound represented by Formula 4 in a hydrocarbon solvent. Specifically, the catalyst system of one embodiment can be produced by contacting and reacting the chromium compound and the pyrrole compound in a mixed solvent of the hydrocarbon solvent and the aluminum compound.

The catalyst system of another embodiment is obtained by, for example, contacting and reacting a chromium compound represented by the formula (1), an aluminum compound represented by the formula (3) and an alumino-pyrrole compound represented by the following formula (5) in a hydrocarbon solvent have.

Another embodiment of the catalyst system comprises a catalyst precursor represented by the following formula (2); And an aluminum compound represented by Formula 3; ≪ / RTI >

In the catalyst system, the catalyst precursor may be a compound represented by the following formula (2).

(2)

Wherein R ² is a hydrocarbon group having 1 to 20 carbon atoms, X is R ² or a halogen atom, R ³ , R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms to be.

In Formula 2, R ² may specifically be a hydrocarbon group, for example, an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 15 carbon atoms, an alkyl group having 1 to 10 carbon atoms, or an alkyl group having 1 to 5 carbon atoms.

In Formula 2, R ³ , R ⁴ , R ^5, and R ⁶ are each independently a hydrogen atom; Or an alkyl group having 1 to 8, 1 to 6, or 1 to 4 carbon atoms, for example.

In Formula 5, the alkyl group may have a linear, branched or cyclic structure. Specifically, examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and an isobutyl group.

In one specific example of the catalyst system, the catalyst precursor of Formula 2 is a compound wherein R ² is a methyl group or an ethyl group, X is the same as R ² or a chlorine atom, R ³ and R ⁶ are methyl groups, R ⁴ and R ⁵ are hydrogen atoms . When such a catalyst precursor is used, the activity of the catalyst system is high.

In the catalyst system of another embodiment described above, the aluminum compound is the same as the aluminum compound represented by the general formula (3) in the foregoing embodiments.

In one embodiment of the catalyst system, the molar ratio (Cr: Al) of the catalyst precursor of Formula 2 and the aluminum compound of Formula 3 is 1: 3 to 1: 100, such as 1:10 to 1:50, 1:10 To 1:40, 1:10 to 1:30, or 1:10 to 1:20. Within the above range, the catalyst system can be realized with high activity while improving the economical efficiency. In such a case, 1-hexene as an ethylene trimer can be obtained in high yield and high purity. In addition, the amount of unreacted material can be reduced to further improve the efficiency of the catalyst system.

The catalyst system of one embodiment comprises a catalyst precursor represented by the following formula (2); And an aluminum compound represented by Formula 3; , And the mixture may be a reactant of the catalyst system of one embodiment described above or a catalyst system of another embodiment.

Another embodiment of the present invention relates to a catalyst precursor represented by the above formula (2). Such a catalyst precursor may be derived from the chromium compound of the above formula (1). The specific contents of the catalyst precursor are as defined in the above-described catalyst system.

The catalyst precursor of one embodiment may be prepared, for example, by way of reaction in the catalyst system of the preceding embodiments; Or a method of reacting the chromium compound of Formula 1 with the compound of Formula 5; And the like. For example, it may be synthesized as described in Production Example 4 or Production Example 5 below.

Another embodiment of the present invention relates to a process for olefin polymerization using the catalyst system described above.

 And contacting the catalyst system with an olefin monomer having 2 to 10 carbon atoms to prepare an olefin polymer (trimer).

Since the catalyst system of the present invention can exist not only in a homogeneous solution state but also in a form supported on a carrier and an insoluble particle form of a carrier, the olefin polymerization (trimerization) reaction can be carried out in liquid phase, slurry phase, bulk phase, Or a gas phase polymerization reaction. Each of the polymerization reaction conditions may be varied depending on the state of the used catalyst composition (homogeneous or heterogeneous phase (supported type)), polymerization method (solution polymerization, slurry polymerization, gas phase polymerization) And can be variously modified. The degree of deformation thereof can be easily performed by a person skilled in the art. When the polymerization is carried out in liquid phase or slurry, the hydrocarbon solvent or olefin monomer itself may be used as the medium. As the hydrocarbon solvent, an aliphatic hydrocarbon solvent having 4 to 20 carbon atoms, an aromatic hydrocarbon solvent having 6 to 20 carbon atoms, a mixture thereof, or the like can be used. Examples of the aliphatic hydrocarbon solvent include isobutane, pentane, hexane, heptane, octane, nonane, decane, cyclohexane and methylcyclohexane. Specific examples of the aromatic hydrocarbon solvent include benzene, toluene, xylene, Tylene, ethylbenzene, cumene, and the like. Normally, the olefin polymerization (trimerization) reaction can be carried out in an aliphatic hydrocarbon solvent in terms of environment. The boiling point of the hydrocarbon solvent used when separating the product from the olefin polymer after the reaction is considered to be preferably 10 to 50 ° C to the boiling point of the product. For example, if the olefin monomer is ethylene and the product is 1-hexene (boiling point: 63 占 폚), cyclohexane having a low unit cost and boiling point of 80.74 占 폚 or methylcyclohexane having a boiling point of 101 占 폚 can be used have.

In an embodiment, examples of the olefin monomer include ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, mixtures thereof and the like. Preferably ethylene can be used alone.

In the olefin polymerization (trimerization) method of the present invention, the amount of the catalyst system to be used is not particularly limited, but the catalyst system of the present invention exhibits high activity, . In an embodiment, when the olefin polymerization method is a solution polymerization, the molar concentration (based on chromium) of the catalyst system is 0.01 to 0.1 mmol / L, for example, 0.01 to 0.03 mmol / L, , An olefin polymer (trimer) such as 1-hexene in which the volume of the solution is produced by continuously feeding an olefin monomer such as ethylene and reacting for 30 minutes to 1 hour can be made about twice as much. For reference, in the known Philips patent, polymerization was carried out at a catalyst concentration of 0.25 mmol / L for reasons of lower catalytic activity than the catalyst system of the present invention (see U.S. Patent No. 5,856,257).

The polymerization temperature may vary depending on the reactants, reaction conditions and the like, and may be 0 to 150 ° C, for example, 60 to 130 ° C. For example, the polymerization can be carried out batchwise, semi-continuously or continuously. The polymerization may also be carried out in two or more stages with different reaction conditions.

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to embodiments of the present invention. It should be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

Example

Production Example 1: Preparation of chromium compound represented by the formula (1)

2-ethyl hexanoic acid (2.44 g, 16.9 mmol) was added to a one-necked flask, and NaOH (0.68 g, 16.9 mmol) was dissolved in distilled water (13 mL) Ethylhexanoate) was formed. The hydrated chromium (III) chloride (CrCl ₃ .6H ₂ O, 1.50 g, 96%, 5.40 mmol) was dissolved in distilled water (1 mL) at 95 ° C, mL) and administered slowly. The reaction proceeded rapidly and the product dissolved into the organic layer. After 2 hours of reaction, all of the product dissolved in the organic layer and became viscous dark blue and the water layer became transparent. The pH of the water layer showed the neutrality, an excess of silver nitrate _{(AgNO 3, 3.03 g, 17.8} mmol) substantially all Cl ion in the CrCl ₃ judging by weight (2.28 g) of the silver chloride (AgCl) which is precipitated when added to (Calculated value, 2.32 g). Hexane (5 mL) was further added to dilute the organic layer. Only the organic layer was removed. The organic layer was then added to distilled water (3 mL) in which NaOH (0.22 g, 5.40 mmol) was dissolved and stirred vigorously for 30 minutes. The 2-ethylhexanoic acid (one equivalent of chromium trivalent salt compound) produced as a byproduct was removed as a water layer in the form of sodium salt. Only the organic layer was removed, and the remaining water was removed with magnesium sulfate. Then, the organic solvent was removed by vacuum drying (0.3 mmHg) at room temperature. Ultramarine chromium compound in solid form _{([{CH 3 (CH 2} ) 3 CH (CH 2 CH 3) CO 2} 2 Cr (OH)] 4 · 2H 2 O) to give a 1.94 g. The yield was 98% based on the structure of [{CH ₃ (CH ₂ ) ₃ CH (CH ₂ CH ₃ ) CO ₂ } ₂ Cr (OH)] ₄ .2H ₂ O.

The IR spectrum of the prepared chromium compound is shown in Fig. IR spectrum analysis revealed an OH stretching signal at 3630 cm ^-1 . Benzene. The molecular weight was found to be 1580 by using freezing point lowering method. The elemental analysis showed that [{CH ₃ (CH ₂ ) ₃ CH (CH ₂ CH ₃ ) CO ₂ } ₂ Cr (OH)] ₄ · in agreement with the structure of the _{2H 2 O (C, 52.48;} H, 8.88; [{CH 3 (CH 2) 3 CH (CH 2 CH 3) CO 2} 2 Cr (OH)] 4 · calcd for _{2H 2 O C, 52.73; H} , 8.85).

When the chromium compound prepared in Preparation Example 1 was dissolved in xylene and refluxed at 160 ° C for 10 hours, the color of the chrome compound remained almost unchanged. It is also confirmed that there is almost no change in the element analysis data value.

Production Example 2: Preparation of alumino-pyrrole compound (B1)

Triethylaluminum (7.20 g, 63.1 mmol) was dissolved in toluene (60 mL) and added to a one-necked flask under an inert atmosphere (nitrogen), and 2,5-dimethylpyrrole (1.50 g, 15.8 mmol) And the mixture was stirred at room temperature for 5 hours. Next, toluene and unreacted triethyl aluminum were removed by vacuum distillation (0.3 mmHg, 70 DEG C) to obtain a pyrrole aluminum compound (1- (diethylalumino) -2,5-dimethylpyrrole ). In the same manner as described above, an alumino-pyrrole compound (B1) having the structure of Formula 5, R ² being an ethyl group, R ³ and R ⁶ being a methyl group, and R ⁴ and R ⁵ being hydrogen was prepared. ^The results of ¹ H NMR analysis were as follows. ^{{Yield: 99%, 1 H NMR (} C 6 D 6): δ 5.51 (s, 2H, Ar-H), 2.01 (s, 6H, CH 3), 1.35 (t, J = 8 Hz, 6H, CH _{3), 0.35 (q, J} = 8 Hz, 4H, CH 2) ppm}.

Production Example 3: Preparation of alumino-pyrrole compound (B2)

A solution of 2,5-dimethylpyrrole (3.00 g, 31.5 mmol) in diethyl ether (30 mL) was cooled to -78 ^° C in a one-necked flask under an inert atmosphere (nitrogen) g, 31.5 mmol, 1.6 M hexane solution) was slowly injected. After stirring overnight at room temperature, the mixture was cooled again to -78 ^° C and dimethylaluminum chloride (Me ₂ AlCl, 20.6 g, 31.5 mmol, 1.0 M hexane solution) was slowly added. After stirring overnight, the solution was filtered to obtain a yellow solution. The solution was vacuum-dried to obtain 6.67 g of (1- (dimethylalumino) -2,5-dimethylpyrrole) compound. In the same manner as above, an alumino-pyrrole compound (B2) having the structure of Formula 5 and having R ² , R ^3, and R ⁶ as a methyl group and R ⁴ and R ⁵ as hydrogen was prepared. ¹ H NMR analysis confirmed that 1 equivalent of diethyl ether was attached (94% yield). _{^{1 H NMR (C 6 D 6}} ): δ 6.23 (s, 2H, CH), 3.15 (q, J = 7.2 Hz, 4H, CH 2), 2.44 (s, 6H, CH 3), 0.55 (t, J = 6.8 Hz, 6H, CH ₃ ), -0.33 (s, 6H, CH ₃ ) ppm}.

Preparation Example 4: Preparation of Catalyst Precursor (P1)

The chromium compound (200 mg, 0.563 mmol) prepared in Preparation Example 1 was dissolved in pentane (9.0 mL) and added to a 25 mL single-necked flask under an inert atmosphere (nitrogen) The p-toluenesulphonyl chloride (380 mg, 1.69 mmol) was dissolved in toluene (1.0 mL) and slowly poured into the two solutions. In the same manner as above, a catalyst precursor (P1) having the structure of Formula 2 and having R ² , X, R ^3, and R ⁶ as a methyl group and R ⁴ and R ⁵ as hydrogen was prepared.

The crystals were immersed (143 mg, yield 65%) while slowly reacting the two solutions in a layered state for one week as described above. The obtained single crystals were analyzed by X-ray diffractometry and shown in Fig.

Production Example 5: Preparation of Catalyst Precursor (P2)

Lithium diisopropylamide (LiNiPr ₂ , 1.50 g, 14.0 mmol) was dissolved in toluene (15 mL) and then diethylaluminum chloride (Et ₂ AlCl, 0.844 g, 7.00 mmol) was slowly added at room temperature to prepare a mixed solution. The obtained lithium chloride was filtered off and the resulting solution was vacuum dried to obtain 1.64 g of white solid LiAlEt ₂ (NiPr ₂ ) ₂ (yield 80%, ¹ H NMR (C ₆ D ₆ ): δ 3.14 (m, 4H, CH ), 1.56 (t, J = 8.0 Hz, 6H, CH 3), 1.01 (d, J = 6.4 Hz, 24H, CH 3), 0.34 (q, J = 7.6 Hz, 4H , CH ₂ ) ppm. ^{_{13 C NMR (C 6 D 6}} ): δ 46.06, 26.25, 11.11, -8.18 ppm}. LiAlEt ₂ (NiPr _{2) 2} (1.00 g, 3.42 mmol) was dissolved in toluene (15 mL), cooled to -30 ° C and then CrCl ₃ (THF) ₃ (1.28 g, 3.42 mmol) was added. During 8 hours of stirring at room temperature, the color of the solution changed from dark green to blue. The solvent was removed using a vacuum pump and hexane (20 mL) was added. The precipitated lithium chloride was removed by filtration, and then cooled to -30 DEG C to obtain crystals (770 mg). After dissolving the crystals obtained in the above manner (100 mg, 0.245 mmol) in toluene (1 mL), the compound of Formula 5 (132 mg, 0.735 mmol) prepared in Example 4 was dissolved in toluene Lt; / RTI >

In the same manner as above, a catalyst precursor (P2) having the structure of Formula (2) wherein R ² is ethyl, X is chlorine atom, R ³ and R ⁶ are methyl groups, and R ⁴ and R ⁵ are hydrogen is prepared.

After the reaction solution was stirred for 1 hour, the pentane was diffused overnight to lower the solubility of the crystals to immerse the crystals (90 mg). X-ray diffraction analysis of the obtained single crystal compound showed the structure in Fig.

Example 1: Preparation of Catalyst System (1)

(110 mg, 0.30 mmol) prepared in Preparation Example 1 was dissolved in toluene (3 mL), 2,5-dimethylpyrrole (86 mg, 0.90 mmol) was added and the temperature was lowered to 0 ° C . A solution of toluene (2 mL) in which triethylaluminum (377 mg, 3.30 mmol) and diethylaluminum chloride (289 mg, 2.40 mmol) were mixed and dissolved was slowly added. When reacted at 0 ° C for 1 hour, a dark yellow solution with almost no precipitate formed. After the temperature rises to room temperature, the dark yellow solution turns into a dark orange solution (concentration: 50 μmol chromium / g-solution).

Example 2: Preparation of catalyst system (2)

(R ² = ethyl, R ³ = R ⁶ = methyl, R ⁴ = R ⁵ = hydrogen) synthesized in Preparation Example 2 Triethyl aluminum (137 mg, 1.20 mmol) and diethyl aluminum chloride (145 mg, 1.20 mmol) were dissolved in methyl cyclohexane (1 mL), and methyl allyl-pyrrole compound (81 mg, 0.45 mmol) Was dissolved in cyclohexane (2 mL), and the mixture was added to prepare a mixed solution. Manufactured blend , A chromium compound (55 mg, 0.15 mmol) prepared in Preparation Example 1 was dissolved in methylcyclohexane (1 mL), and the mixture was reacted to prepare a catalyst system of a dark green transparent solution having almost no precipitate Concentration: 50 mmol chromium / g-solution). A photograph of the prepared catalyst system is shown in Fig.

Example 3: Preparation of catalyst system (3)

Pyrrole compound represented by the formula 5 (R ² = ethyl, R ³ = R ⁶ = methyl and R ⁴ = R ⁵ = hydrogen) prepared in Preparation Example 2 was used instead of the alumino-pyrrole compound represented by the formula 5 Pyrrol compounds represented by the following general formula (1) wherein R ² = methyl, R ³ = R ⁶ = methyl and R ⁴ = R ⁵ = hydrogen are used, trimethylaluminum and dimethylaluminum chloride are used instead of triethylaluminum and diethylaluminum chloride (Concentration: 50 占 퐉 ol chromium / g-solution), except that the solution was used. When the prepared catalyst system was stored at room temperature for one month, some single crystals of the reaction intermediate were precipitated. When the structure of the catalyst intermediate was analyzed by X-ray diffraction, a cluster compound composed of four chromium atoms was confirmed as shown in FIG. 4 .

Example 4: Preparation of Catalyst System (4) Containing Catalyst Precursor

(10 mg, 25.5 μmol) represented by the formula 2 (R ² = X = methyl, R ³ = R ⁶ = methyl and R ⁴ = R ⁵ = hydrogen) synthesized in Preparation Example 4 was dissolved in methyl (137 mg, 1.20 mmol) and diethyl aluminum chloride (145 mg, 1.20 mmol) were dissolved in methylcyclohexane (0.7 mL), and the solution was added to a dark green transparent solution (Concentration: 50 μmol chromium / g-solution).

Example 5: Preparation of a catalyst system (5) comprising a catalyst precursor

Except that the compound represented by the formula 2 (R ² = X = methyl, R ³ = R ⁶ = methyl and R ⁴ = R ⁵ = hydrogen) prepared in Preparation Example 5 was used instead of the compound represented by the formula 2 ² = ethyl, X = chlorine, R ³ = R ⁶ = methyl, R ⁴ = R ⁵ = hydrogen), and it is the embodiment except that there was used the compound shown in example 4 and the transparent solution was dark green in the same manner as the catalyst system (Concentration: 50 μmol chromium / g-solution).

Comparative Example 1: Production of Phillips' four catalyst system

And the method disclosed in U.S. Patent No. 5,856,257. After dissolving tris (2-ethylhexanoate) chromium (III) (Cr (EH) ₃ ) (145 mg, 0.30 mmol) in toluene (3 mL), 2,5-dimethylpyrrole (86 mg, 0.90 mmol ) Was added and the temperature was lowered to 0 < 0 > C. A solution of toluene (2 mL) in which triethylaluminum (377 mg, 3.30 mmol) and diethylaluminum chloride (289 mg, 2.40 mmol) were mixed and dissolved was slowly added. Black precipitate formed when reacted at 0 ℃ for 1 hour. The precipitate formed by filtration was removed to obtain a clear deep orange catalyst system solution. The pre-filtration photograph of the prepared catalyst system is shown in Fig.

Comparative Example 2: Production of Phillips' four catalyst system

Chromium (III) (Cr (EH) ₃ ) was prepared in the same manner as in Comparative Example 1, except that the products of different product numbers from the same manufacturer were used.

Examples 6 to 10: Ethylene trimerization reaction using the catalyst system of the examples

Methylcyclohexane (20 mL) and triethylaluminum (0.024 mmol) were charged into a high-pressure polymerization reactor in a dry box and then taken out of the dry box, and the temperature was raised to 90 ° C. The catalyst systems (0.25 μmol to 1.00 μmol) prepared in Examples 1 to 5 were quantitatively taken and then methylcyclohexane was added to make the total solution 2 mL. In addition, triethylaluminum (8 equivalents to chromium) and diethylaluminum chloride (8 equivalents to chromium) were added to the scavenger as a reason for taking a very small amount of the catalyst, the catalyst solution was injected into the reactor after taking the syringe Ethylene was injected at a pressure of 50 bar and polymerized for 30 minutes. After rapidly heating to 0 ° C, ethylene gas was removed by venting, and 5 mL of ethanol and 5 mL of 10% hydrochloric acid were added to terminate the reaction. Some samples were taken to determine the amount of 1-hexene produced via gas chromatography. Further, the total solution was filtered to measure the amount of the solid polymer formed. The results are shown in Table 1 below.

Comparative Examples 3 to 4: Ethylene trimerization reaction using the catalytic system of Comparative Example

In a dry box, methylcyclohexane (20 mL) and triethylaluminum (0.024 mmol) were charged into a high-pressure polymerization reactor and then taken out of the dry box, and the temperature was raised to 90 ° C. The catalyst system solutions (1.00 μmol to 2.00 μmol) prepared in Comparative Examples 1 and 2 were quantified and then methylcyclohexane was added to make the total solution 2 mL. The catalyst solution was injected into the reactor by injecting the injector, and ethylene was injected at a pressure of 50 bar to polymerize for 30 minutes. After rapidly heating to 0 ° C, ethylene gas was removed by venting, and 5 mL of ethanol and 5 mL of 10% hydrochloric acid were added to terminate the reaction. Some samples were taken to determine the amount of 1-hexene produced via gas chromatography. Further, the total solution was filtered to measure the amount of the solid polymer formed. The results are shown in Table 1 below.

Comparative Example 5: Preparation of a chromium compound having no structure (1) ({CH ₃ CH ₂ CH (CH ₂ CH ₃ ) CO ₂ } ₂ Preparation of Cr (OH)

A compound was prepared in the same manner as in Preparation Example 1, except that 2-ethylbutyric acid (16.9 mmol) was used instead of 2-ethylhexanoic acid. 1.62 g of a compound in the form of a dark blue solid was obtained (100% yield).

After dissolving the above compound in benzene freezing point to molecular weight measurement result 3330 by the descending method _{{CH 3 CH 2 CH (CH} 2 CH 3) CO 2} 2 Cr (OH) aggregate at about 11 dogs molecular benzene (i. E., [ {CH ₃ CH ₂ CH (CH ₂ CH ₃ ) CO ₂ } ₂ Cr (OH)] ₁₁ ).

The compound prepared in Comparative Example 5 corresponds to the structure of {CH ₃ CH ₂ CH (CH ₂ CH ₃ ) CO ₂ } ₂ Cr (OH) in which no water molecule is contained in the elemental analysis (C, 48.52; H, 7.85 ; {CH ₃ CH ₂ CH (CH ₂ CH ₃ ) CO ₂ } ₂ C (OH) calculated for C, 48.15; H, 7.75).

The compound prepared in Comparative Example 5 was dissolved in xylene and then refluxed at 160 ° C for 10 hours to change color to change from gray to green and to change in elemental analysis data (C, 50.85, H, 7.96 ).

As a result, it was found that the compound prepared in Comparative Example 5 had a completely different structure from the chromium compound of Formula (1). In addition, it was confirmed that the compound prepared in Comparative Example 5 had a large viscosity by being present in the form of an 11-dimer, which is not suitable for application to a catalyst system.

Comparative Example 6: Preparation of chromium compound having no structure of formula (1)

The procedure of Production Example 1 was repeated except that 2,2-dimethylpropionic acid was used instead of 2-ethylhexanoic acid. After the compound was synthesized, vacuum decompression was performed at 120 ° C to remove the 2,2-dimethylpropionic acid produced as a solvent and a by-product, thereby forming a gel that was not dissolved in the hydrocarbon solvent.

As a result, it was found that the compound prepared in Comparative Example 6 was completely different from the chromium compound of Formula 1 prepared in Preparation Example 1. In addition, it was found that the compound of Comparative Example 6 was insoluble in a hydrocarbon solvent.

Comparative Example 7: Preparation of chromium compound having no structure of formula (1)

Except that heptanoic acid was used in place of 2-ethylhexanoic acid. After the synthesis of the compound, vacuum decompression was performed at 120 ° C to remove the heptanoic acid produced as a solvent and a by-product, and a gel not soluble in the hydrocarbon solvent was formed.

As a result, it was found that the compound prepared in Comparative Example 7 was completely different from the chromium compound of Formula 1 prepared in Preparation Example 1. It was also found that the compound of Comparative Example 7 was insoluble in hydrocarbon solvents.

Comparative Example 8: Preparation of chromium compound having no structure of formula (1)

The procedure of Production Example 1 was repeated except that benzoic acid was used instead of 2-ethylhexanoic acid. During the course of the reaction, a milky blue gel that did not dissolve in the hydrocarbon solvent was formed.

As a result, it was found that the compound prepared in Comparative Example 8 was completely different from the chromium compound of Formula 1 prepared in Preparation Example 1. Further, it was found that the compound of Comparative Example 8 was insoluble in a hydrocarbon solvent.

Comparative Example 9: Preparation of chromium compound having no structure of formula (1)

The procedure of Production Example 1 was repeated except that cyclohexanecarboxylic acid was used instead of 2-ethylhexanoic acid. During the course of the reaction, a milky blue gel that did not dissolve in the hydrocarbon solvent was formed.

As a result, it was found that the compound prepared in Comparative Example 9 was completely different from the chromium compound of Formula 1 prepared in Preparation Example 1. Further, it was found that the compound of Comparative Example 9 was insoluble in a hydrocarbon solvent.

Property evaluation method

(1) Activity (unit: Kg (1-hexene) / g (catalyst (Cr)) / hr): The mass of 1-hexene obtained is divided by the amount of catalyst added.

(2) Identification of structure of compounds: For the compounds prepared in Comparative Examples 5 to 9, benzene free point measurement and elemental analysis were carried out. Based on the result, it was evaluated whether or not it was consistent with the structure of the formula (1) obtained in Preparation Example 1. The results are shown in Table 2 below. &Quot;? &Quot;

(3) Evaluation of stability of compounds: The compounds prepared in Preparation Example 1 and Comparative Example 5 were respectively dissolved in xylene and refluxed at 160 DEG C for 10 hours to evaluate the stability. When there is little change in the color and elemental analysis results after 10 hours of reflux, the results are shown as "? &Quot;, and when the color and elemental analysis results are greatly changed after 10 hours of refluxing, the results are evaluated as " X "

Example Comparative Example 6 7 8 9 10 3 4 Catalyst system Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 The amount of catalyst (μmol) 0.25 0.25 1.00 1.00 1.00 1.00 1.00 The amount of 1-hexene obtained (g) 6.9 7.1 5.6 12.4 6.4 7.2 3.2 activation
(Kg (1-hexene) / g (Cr) / h) 1070 1,100 220 500 260 280 120 Dimer C ₄ (wt%) 4.26 0.70 0.24 3.21 0.86 0.52 1.00 The trimer C ₆ (wt%) 88.08 94.12 92.38 88.08 93.60 92.97 93.04 Tetramer C ₈ (wt%) 0.29 0.48 0.39 0.39 0.32 0.38 0.64 Pentamer C ₁₀ (wt%) 7.37 4.70 6.99 8.32 5.22 6.08 5.33 The content of 1-hexene in the trimer (wt%) 99.21 98.42 98.77 98.2 98.56 98.85 97.78 PE yield (mg) 27 27 35 17 6 32 11

Production Example 1 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Identification of chemical structure of compounds ○ X X X X X Solubility in hydrocarbon solvents ○ ○ X X X X Evaluation of the stability of the compound Great Bad - - - -

From the above results, the catalyst systems of Examples 6 to 10 containing the chromium compounds of Formula 1 or the chromium-based catalyst precursors of Formula 2 showed significantly higher catalytic activity than the catalyst systems of Comparative Examples 3 to 4 And the catalyst cost can be remarkably reduced.

 In addition, the catalyst systems of Examples 6 to 10 are capable of producing a catalyst in an aliphatic hydrocarbon solvent, so that there is no need to remove the aromatic hydrocarbon solvent for trimerization of ethylene in the aliphatic hydrocarbon solvent, And the catalyst system manufacturing process is simple and easy.

In addition, it was found that the chromium compound having the structure of the formula (1) prepared in the same manner as in Production Example 1 is excellent in stability and solubility in hydrocarbon solvents and has characteristics suitable for application to a catalyst system.

On the other hand, it was found that the compounds having no structure of the formula 1 of the present invention prepared as in Comparative Examples 5 to 9 were highly viscous and thus unsuitable for use in a catalyst system or insoluble in a hydrocarbon solvent and low in stability.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims (16)

A chromium compound represented by the following formula (1):
[Chemical Formula 1]
[{CH ₃ (CH ₂ ) ₃ CH (CH ₂ CH ₃ ) CO ₂ } ₂ Cr (OH)] ₄ .2H ₂ O A chromium compound represented by the following formula (1);
An aluminum compound represented by the following formula (3); And
A pyrrole compound represented by the following formula (4); ≪ / RTI > a catalyst system for olefin polymerization comprising:
[Chemical Formula 1]
[{CH ₃ (CH ₂ ) ₃ CH (CH ₂ CH ₃ ) CO ₂ } ₂ Cr (OH)] ₄ .2H ₂ O
(3)
(R ² ) _n Al (X ² ) _3-n
In Formula 3, R ² is a hydrocarbon group having 1 to 20 carbon atoms, X ² is a halogen atom, and the average value of n is 1 to 3;
[Chemical Formula 4]

In Formula 4, R ³ , R ⁴ , R ^5, and R ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. The method of claim 2, wherein the aluminum compound is triethylaluminum (Et ₃ Al) and diethylaluminum chloride (Et ₂ AlCl) and mixtures thereof;
Wherein the pyrrole compound is 2,5-dimethylpyrrole. The catalyst system for olefin polymerization according to claim 2, wherein the catalyst system has a molar ratio (Cr: Al) of the chromium compound and the aluminum compound introduced at the time of production (reaction) in the range of 1:10 to 1:50. 3. The catalyst system for olefin polymerization according to claim 2, wherein the catalyst system has a molar ratio (chromium compound: pyrrole compound) of the chromium compound and the pyrrole compound introduced at the time of production (reaction) in the range of 1: 1 to 1: A chromium compound represented by the following formula (1);
An aluminum compound represented by the following formula (3); And
An alumino-pyrrole compound represented by the following formula (5); ≪ / RTI > a catalyst system for olefin polymerization comprising:
[Chemical Formula 1]
[{CH ₃ (CH ₂ ) ₃ CH (CH ₂ CH ₃ ) CO ₂ } ₂ Cr (OH)] ₄ .2H ₂ O
(3)
(R ² ) _n Al (X ² ) _3-n
In Formula 3, R ² is a hydrocarbon group having 1 to 20 carbon atoms, X ² is a halogen atom, and the average value of n is 1 to 3;
[Chemical Formula 5]

Wherein R ² is a hydrocarbon group having 1 to 20 carbon atoms and R ³ , R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. 7. The method of claim 6 wherein the aluminum compound is triethylaluminum (Et ₃ Al) and diethylaluminum chloride (Et ₂ AlCl) and mixtures thereof;
In the formula (5), R ³ and R ⁶ are methyl groups, R ⁴ and R ⁵ are hydrogen atoms, and R ² is an ethyl group. 7. The catalyst system for olefin polymerization according to claim 6, wherein the catalyst system further comprises an aliphatic hydrocarbon solvent. A catalyst precursor represented by the following formula (2); And
An aluminum compound represented by the following formula (3); A catalyst system for olefin polymerization comprising:
(2)

Wherein R ² is a hydrocarbon group having 1 to 20 carbon atoms, X is R ² or a halogen atom, R ³ , R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms to be.
(3)
(R ² ) _n Al (X ² ) _3-n
In the above formula (3), R ² is a hydrocarbon group having 1 to 20 carbon atoms, X ² is a halogen atom, and the average value of n is 1 to 3. [10] The method according to claim 9, wherein in Formula 2, R ² is methyl or ethyl, X is R ² or a chlorine atom, R ³ and R ⁶ are methyl, and R ⁴ and R ⁵ are hydrogen atoms. 10. The method of claim 9, wherein the aluminum compound is triethylaluminum (Et ₃ Al) and diethylaluminum chloride (Et ₂ AlCl) mixture of the catalyst system. The catalyst system of claim 9, wherein the reactant has a molar ratio (Cr: Al) of a catalyst precursor and an aluminum compound of 1:10 to 1:50. A catalyst precursor represented by the following formula (2):
(2)

Wherein R ² is a hydrocarbon group having 1 to 20 carbon atoms, X is R ² or a halogen atom, R ³ , R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms to be. The catalyst precursor according to claim 13, wherein R ² is methyl or ethyl, X is R ² or a chlorine atom, R ³ and R ⁶ are methyl, and R ⁴ and R ⁵ are hydrogen atoms. A process for olefin polymerization comprising contacting an olefin polymer with a catalyst system according to any one of claims 2 to 12 and an olefin monomer having 2 to 10 carbon atoms. The olefin polymerization process according to claim 15, wherein the olefin monomer is ethylene, and the olefin polymer is an olefin trimer.

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