KR101880810B1 - Process for olefin oligomerization - Google Patents

Abstract

As a method for selectively oligomerizing olefins including ethylene, a method for preparing olefin oligomers using a novel catalyst system capable of tripletization and quaternization of olefins unlike the olefin oligomerization catalyst systems reported so far is disclosed. The present invention relates to a ligand compound represented by formula (1); Chromium compounds; And a metal alkyl compound, in the presence of an olefin oligomerization catalyst system.

Description

PROCESS FOR OLEFIN OLIGOMERIZATION < RTI ID = 0.0 >

The present invention relates to a process for preparing olefin oligomers, and more particularly, to a process for preparing olefin oligomers capable of trimerization and quantification of olefins.

Linear alpha-olefins are widely used commercially as important materials for comonomers, detergents, lubricants, plasticizers and the like. Particularly, 1-hexene and 1-octene are used in the production of linear low density polyethylene (LLDPE) Is used as a comonomer for controlling the density of the polymer.

Specifically, previously known processes for preparing LLDPE include forming alpha-olefins such as 1-hexene, 1-octene, and 1-hexene in order to control the density by forming branches in the polymer backbone together with ethylene. And the like. Therefore, in producing LLDPE having a high comonomer content, the cost of the comonomer is a large part of the manufacturing cost. Accordingly, various attempts have been made to reduce the production cost of such comonomers. In addition, since the application fields and the market sizes of the alpha-olefins vary depending on the type, the production of a specific alpha-olefin selectively

The technology that can be used is of great commercial significance, and recent research into chromium catalyst technology for producing 1-hexene, 1-octene, etc. at a high selectivity through selective ethylene oligomerization has been conducted.

For example, as a catalyst system for producing 1-hexene or the like by polymerizing an olefin such as ethylene, a catalyst comprising chromium 3 as a compound, a pyrrole compound, a non-hydrolyzed aluminum alkyl and an unsaturated hydrocarbon (unsaturated (see U.S. Patent No. 5,376,612), and thereafter commercial production of 1-hexene starting from 2003 based on the above catalyst system have. Catalytic systems using tris (2-ethylhexanoate) chromium (III) (Cr (EH) ₃ , EH = O2C8H15) among various chromium trivalent compounds showed particularly good catalytic activity and use Cr (EH) ₃ The catalyst system has been intensively studied and commercialized.

Such a catalyst system using Cr (EH) ₃ can be prepared by, for example, adding a mixed solution of triethylaluminum and ethylaluminum dichloride to an unsaturated hydrocarbon solvent (toluene etc.) in which Cr (EH) ₃ and 2,5- In an unsaturated hydrocarbon solvent. Since the trimerization reaction of olefins is usually carried out in a saturated hydrocarbon solvent such as cyclohexane, the unsaturated hydrocarbon solvent of the prepared catalyst system is removed by vacuum decompression and then re-dissolved in a saturated hydrocarbon solvent such as cyclohexane, The unsaturated hydrocarbon solution phase catalyst system is used in the trimerization reaction, and after the reaction, the unsaturated hydrocarbon solvent used for preparing the catalyst should be separated and removed. In addition, since Cr (EH) ₃ is used as a byproduct for forming a catalytic activated species during the production of catalyst, black precipitate is formed as a by-product, and therefore, a process for removing it by filtration is required (see US Pat. No. 5,563,312). Such an unsaturated hydrocarbon solvent removing step such as toluene, a filtration step, etc., can be a burden for commercialization. When the above catalyst system is produced in an aliphatic hydrocarbon solvent such as cyclohexane in which the trimerization reaction is carried out in order to omit the unsaturated hydrocarbon solvent removing step, the thermal stability of the produced catalyst is lowered, (See U.S. Patent No. 5,563,312), unsaturated hydrocarbons are included as an essential component in the catalytic systems of the above-mentioned Phillips catalysts and the like.

International Patent Publication WO2015 / 133805 discloses a process for producing a catalyst system in which a by-product is not produced during the production of a catalyst, so that a filtration process or the like is not necessary, and a raw material compound of a catalyst system capable of producing a catalyst system in a saturated hydrocarbon solvent, A catalyst system excellent in activity has been disclosed.

However, all of the prior patents have a problem in that only tripletization proceeds in the process of proceeding to olefin oligomerization.

The present invention provides a method of selectively oligomerizing olefins including ethylene, and a method for preparing olefin oligomers using a novel catalyst system capable of tripletization and quaternization of olefins unlike the olefin oligomerization catalyst systems reported so far.

In order to solve the above problems, the present invention provides a ligand compound represented by the following formula (1): Chromium compounds; And a metal alkyl compound, in the presence of an olefin oligomerization catalyst system.

[Chemical Formula 1]

Wherein E1 to E4 each independently represent an element of boron (B), carbon (C), nitrogen (N), oxygen (O), silicon (Si), phosphorus (P) or sulfur (S) (B), nitrogen (N), oxygen (O), silicon (Si), phosphorus (P) or sulfur (S) elements, and B1 is at least one element selected from the group consisting of aluminum (Al) Wherein R 1 to R 9 are each independently selected from the group consisting of hydrogen, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 1 to 20 carbon atoms, An alkylsilyl group, a haloalkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 40 carbon atoms, an arylalkyl group having 7 to 20 carbon atoms, an arylsilyl group having 6 to 20 carbon atoms Arylsilyl) group, an Alkylaryl group having 7 to 20 carbon atoms, an Aryloxy group having 6 to 20 carbon atoms, a Halogen group or an amino group)

Wherein E1 in the formula (1) is nitrogen (N) and E2 is oxygen (O), E3 is nitrogen (N) and E4 is oxygen (O).

And the chromium compound is chromium (III) or chromium (II) containing compound.

And wherein said olefin oligomerization comprises trimerization and quaternization.

And the olefin oligomerization reaction is carried out in a homogeneous liquid phase reaction.

And the olefin oligomerization reaction is carried out in an inert solvent that does not react with the catalyst compound.

And the olefin oligomerization reaction is carried out at a temperature of 0 to 250 ° C and a pressure of 1 to 200 bar.

The present invention relates to a novel catalyst system capable of selectively trimerizing and quaternizing olefins including ethylene by applying a compound not conventionally employed as a ligand compound in the production of olefin oligomers, Octene can be produced.

Hereinafter, preferred embodiments of the present invention will be described in detail. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Throughout the specification, when an element is referred to as "including " an element, it means that it can include other elements, not excluding other elements, unless specifically stated otherwise.

The present invention relates to ligand compounds; Chromium compounds; And a metal alkyl compound, in the presence of an olefin oligomerization catalyst system.

The catalyst system for olefin oligomerization according to the present invention is used in an olefin oligomerization method comprising the step of mass-reacting olefins in the presence of this catalyst system. According to the present invention, olefins including ethylene can be selectively quantized and quaternized.

Hereinafter, a catalyst system for olefin oligomerization according to a specific embodiment of the present invention will be described in detail.

In the present invention, the ligand compound is a compound represented by the following formula (1).

[Chemical Formula 1]

E1 to E4 each independently represent an element selected from boron (B), carbon (C), nitrogen (N), oxygen (O), silicon (Si), phosphorus (P) E2 may be boron (B), nitrogen (N), oxygen (O), silicon (Si), phosphorus (P) or sulfur (S) E2 may be oxygen (O), E3 may be nitrogen (N), and E4 may be oxygen (O).

B1 may be aluminum (Al), boron (B), nitrogen (N), or phosphorus (P) element, preferably aluminum (Al).

Each of R1 to R9 independently represents hydrogen, an alkyl (Alky) group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, a halo An arylalkyl group having 6 to 40 carbon atoms, an arylalkyl group having 7 to 20 carbon atoms, an arylsilyl group having 6 to 20 carbon atoms, an alkylaryl group having 7 to 20 carbon atoms An aryloxy group having 6 to 20 carbon atoms, a halogen group or an amino group. Wherein the aryl group is optionally substituted with at least one substituent selected from the group consisting of phenyl, biphenyl, triphenyl, triphenylene, naphthalenyl, anthracenyl, phenalenyl, phenanthrenyl, fluorenyl, pyrenyl, Aromatic hydrocarbon functional groups, dibenzothiophenyl, dibenzofuranyl, dibenzoselenophenyl, furanyl, thiophenyl, benzofuranyl, benzothiophenyl, benzoselenophenyl, carbazonyl, indolocarbazolyl, Pyridyl, pyridyl, pyridyl, pyridyl, pyridyl, pyridyl, pyridyl, pyridyl, pyridyl, pyridyl, pyridyl, pyridyl, pyridyl, pyrimidinyl, Pyrimidyl, pyrazinyl, triazinyl, oxazinyl, oxathiazinyl, oxadiazinyl, indolinine, benzimidazolyl, indazolyl, indoxazinyl, benzoxazolyl, benzisoxazolyl, benzothiazolyl, quinolyl Nin, isoquinolinyl, cinnolinyl, quinazolyl, quinoxalinine, But are not limited to, phthalidyl, phthalazinyl, phthalidinyl, xanthenyl, acridyl, phenazinyl, phenothiazinyl, phenoxazinyl, benzofuropyridyl, furodipyridyl, benzothienopyridyl, Aromatic heterocyclic functional groups such as benzenesulfonylphenidyl, benzoselenophenopyridyl, selenophenodipyridyl, and the like.

R 1 to R 9 in Formula 1 are preferably hydrogen, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, or an aryl group, from the viewpoint of stabilization of the central metal.

The term " olefin oligomerization " as used herein means that the olefin is polymerized. It is called "trimerization" and "tetramerization" according to the number of olefins to be polymerized, and is collectively referred to as "multimerization". In particular, the present invention means to selectively produce 1-hexene and 1-octene from ethylene.

The term 'catalyst system' refers to a state in which the ligand compound, the chromium compound, and the metal alkyl compound are simply mixed together, or whether they form a separate catalytically active species, or their reaction product Any composition, compound or complex that exhibits catalytic activity for ' olefin oligomerization ' including catalytically active species may be collectively referred to.

The optional olefin oligomerization reaction is also closely related to the catalyst system used. The catalyst system used in the olefin oligomerization reaction includes a chromium compound serving as a main catalyst and a metal alkyl compound as a cocatalyst wherein the structure of the active catalyst can be changed according to the chemical structure of the ligand, The activity becomes different.

The present inventors have found that a ligand compound having a specific structure as described above and a catalyst system for olefin oligomerization comprising a metal compound as a chromium compound and a promoter can control the electronic and stereoscopic environment around a transition metal by suitably controlling the ligand compound Therefore, it has been confirmed through experimentation that oligomerization of olefins, especially trimerization and tetramerization, is possible with high catalytic activity and selectivity, and the present invention has been completed.

Particularly, the ligand compound is a hexagonal ring compound. The ligand compound is a hexagonal ring compound, and includes boron (B), nitrogen (N), oxygen (O), silicon (Si), phosphorus (P), sulfur ). Due to such structural features, the ligand compound can be applied to oligomerization catalyst systems of olefins to exhibit a high oligomerization reaction activity, and particularly, 1-hexene and 1-octene Can exhibit a high degree of selectivity. This is presumably due to the interaction between each adjacent chromium active point.

In the present invention, the chromium compound acts as a main catalyst, and it is preferable to use a compound containing chromium (III) or chromium (II) because the reaction activity can be enhanced.

Examples of the chromium (III) compound include chromium carboxylate, chromium naphthenate, chromium halide and chromium dionate. More specific examples thereof include chromium (III) 2,2,6,6-tetramethylheptanedio (III) naphthenate [Cr (NP) 3], bis (2-ethylhexanoate), chromium ) Chromium (III) hydroxide, bis (2-butanoate) chromium (III) hydroxide, chromium (III) chloride, iodine chromium bromide, iodine chromium, chromium (III) acetylacetonate, chromium ) Acetate, chromium (Ⅲ) butyrate, chromium (Ⅲ) neopentanoate, chromium (Ⅲ) laurate, chromium (Ⅲ) stearate, chromium (Ⅲ) oxalate, bis (2-ethylhexanoate) III) hydroxide, and the like.

Specific examples of the chromium (II) compound include chromium bromide, chromium fluoride, chromium (II) chloride, chromium (II) acetate, chromium (II) (II) neopentanoate, chromium (II) laurate, chromium (II) stearate, chromium (II) oxalate and the like.

Meanwhile, the chromium compound may be in a state dissolved in a hydrocarbon solvent. The hydrocarbon solvent is an inert solvent which does not react with a chromium compound or a cocatalyst and may be selected from benzene, benzene, toluene, heptane, cyclohexane, methylcyclohexane, methylcyclopentane, hexane, pentane, butane, isobutane, But is not limited thereto.

(III) 2-ethylhexanoate, chromium (III) acetylacetonate or bis (2-ethylhexanoate) chromium (III) hydroxide is used as the chromium compound in the olefin oligomerization catalyst system of this embodiment , It is preferable to use it by dissolving it in anhydrous toluene or anhydrous cyclohexane solvent in view of the improvement of the catalytic activity by the difference in the solubility of the solvent.

In the present invention, the metal alkyl compound is not particularly limited as long as it can be used as a cocatalyst in an olefin oligomerization catalyst system and is generally used for mass-producing olefins under a transition metal compound catalyst. For example, as the metal alkyl compound, an alkyl aluminum compound, an alkyl boron compound, an alkyl magnesium compound, an alkyl zinc compound, an alkyl lithium compound and the like can be used.

However, in order to exhibit high selectivity and activity in the olefin oligomerization reaction, an alkylaluminum compound can be used as the above-described promoter compound. Specific examples of such alkylaluminum compounds include triethylaluminum, tripropylaluminum, tributylaluminum, diethyl There may be mentioned aluminum chloride, diethylaluminum bromide, diethylaluminum ethoxide, diethylaluminum phenoxide, ethylaluminum dichloride, ethylaluminum sesquichloride and the like, preferably triethylaluminum, ethylaluminum dichloride, ethylaluminum Sesquichloride can be mixed and used. In such a case, it is preferable to effectively remove moisture and improve catalytic activity including electron donating atoms.

The molar ratio of the ligand compound: chromium compound: metal alkyl compound is in the range of 0.5: 1: 1 to 10: 1: 1, in order to increase the selectivity for the linear alpha-olefin and increase the mass- 10,000, preferably 0.5: 1: 100 to 5: 1: 3,000. However, the present invention is not limited thereto.

In the catalyst system for olefin oligomerization comprising the ligand compound, the chromium compound and the metal alkyl compound, the three components may be used in combination with one or more precursors thereof, either simultaneously or in any order, in any suitable solvent, Can be added to give an active catalyst. Suitable solvents include, but are not limited to, heptane, toluene, cyclohexane, methylcyclohexane, 1-hexene, diethyl ether, tetrahydrofuran, acetonitrile, dichloromethane, chloroform, chlorobenzene, methanol and acetone.

There is provided a process for preparing an olefin oligomer comprising the step of mass-reacting an olefin in the presence of the above-mentioned catalyst system for olefin oligomerization. The use of the catalyst system for olefin oligomerization according to the present invention can provide a method for oligomerization of olefins in which the activity of the reaction is improved. At this time, the olefin is preferably ethylene.

In the present invention, the olefin oligomerization is carried out by using the olefin oligomerization catalyst system and a conventional apparatus and contact technique, in a homogeneous liquid phase reaction in the presence or absence of an inert solvent, a slurry reaction in which the catalyst system is partially or completely dissolved, Liquid / liquid reaction or product phase reaction or gas phase reaction in which the olefin serves as the main medium, preferably a homogeneous liquid phase reaction can be employed.

The olefin oligomerization reaction may be carried out in any inert solvent that does not react with the catalyst compound and the activator. Suitable inert solvents include, but are not limited to, benzene, toluene, xylene, cumene, heptane, cyclohexane, methylcyclohexane, methylcyclopentane, hexane, pentane, butane and isobutane. At this time, the solvent may be treated with a small amount of alkylaluminum to remove a small amount of water or air acting as a catalyst poison.

The olefin oligomerization reaction may be carried out at a temperature of 0 to 250 ° C, preferably 20 to 200 ° C, more preferably 40 to 130 ° C. Excessively low reaction temperatures can produce, for example, undesirable insoluble products such as polymers in excess, and excessively high temperatures can cause decomposition of the catalyst system and reaction products, Do. In addition, the olefin oligomerization reaction can be carried out at a pressure of 1 to 200 bar, preferably 10 to 150 bar. Excessively low reaction pressures can result in low catalytic activity. In the process for preparing the olefin oligomer, hydrogen may be added to the reactor at 0.01 to 50 bar, preferably at 0.5 to 10 bar, in order to promote the reaction or to increase the activity of the catalyst system.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Manufacturing example  One: Ligand  Compound manufacturing

2,6-Dimethylmorpholine (30 mmol) was dissolved in toluene (60 mL) under an inert atmosphere (nitrogen) in a two-necked flask, and the mixture was cooled to 0 캜 with ice while stirring. When the temperature was sufficiently lowered, n-butyllithium (66 mmol, 2.5M in Hexane Aldrich reagent) was slowly added dropwise over 10 minutes. After the addition was completed, the reaction solution was maintained at 0 ° C for 1 hour, and then the ice was removed from the reaction solution and the temperature was raised to room temperature. After stirring for 12 hours, toluene as a solvent was removed under reduced pressure. The resulting white solid was washed twice with hexane (20 mL) in which water was removed. The washed white solid was dried under reduced pressure and dissolved again in toluene (60 mL). The temperature of the reaction solution was lowered to -78 ° C using dry ice, and then ethylaluminum dichloride (15 mmol, 25 wt% in toluene Aldrich reagent) was slowly added dropwise for 10 minutes. After stirring at the same temperature for 1 hour, the temperature was raised to room temperature and the reaction was carried out for 12 hours. After completion of the reaction, the resulting white solid was filtered and reduced in pressure to remove the toluene solvent. The resulting yellow oil was dissolved again in toluene (4 mL) and recrystallized at -3 DEG C to prepare a ligand compound represented by the following formula (2)

(2)

Example : Catalyst system  Produce

Example  One

The reaction was carried out in an inert atmosphere using chromium (III) 2-ethylhexanoate (21.3 mmol), ligand compound (63.8 mmol) prepared in Preparation Example 1, ethyl aluminum dichloride (85.1 mmol) (Nitrogen). Specifically, chromium (III) 2-ethylhexanoate was dissolved in 30 mL anhydrous toluene and the ligand was added. Ethyl aluminum dichloride and triethyl aluminum were mixed together in a separate vessel. The aluminum alkyl solution was then slowly poured into the chromium / ligand solution. The reaction solution was stirred for 5 minutes and then the solvent was removed under vacuum. The remaining oily liquid was diluted with cyclohexane to 150 mL and the solution was filtered to remove the black precipitate from the filtrate containing the catalyst system and diluted with toluene to a volume of 250 mL to produce the final catalyst system.

Example  2

A catalyst system was prepared in the same manner as in Example 1, except that chromium (III) acetylacetonate was used instead of chromium (III) 2-ethylhexanoate in Example 1.

Example  3

A catalyst system was prepared in the same manner as in Example 1, except that bis (2-ethylhexanoate) chromium (III) hydroxide was used instead of chromium (III) 2-ethylhexanoate in Example 1.

Comparative Example

(Under nitrogen) using chromium (III) 2-ethylhexanoate (21.3 mmol), 2,5-dimethylpyrrole (63.8 mmol), ethylaluminum dichloride (85.1 mmol) and triethylaluminum (319 mmol) A representative catalyst system was prepared. Specifically, chromium (III) 2-ethylhexanoate was dissolved in 30 mL anhydrous toluene and the ligand was added. Ethyl aluminum dichloride and triethyl aluminum were mixed together in a separate vessel. The aluminum alkyl solution was then slowly poured into the chromium / ligand solution. The reaction solution was stirred for 5 minutes and then the solvent was removed under vacuum. The remaining oily liquid was diluted with cyclohexane to 150 mL and the solution was filtered to remove the black precipitate from the filtrate containing the catalyst system and diluted with toluene to a volume of 250 mL to produce the final catalyst system.

Experimental Example

A 2 L stainless steel reactor was charged with nitrogen, 1 L of cyclohexane was added, 3 mL of triethylaluminum was added, ethylene was charged to 10 bar, and the temperature was raised to 90 캜. Each of the prepared catalyst solutions (30 μmol) was charged into a reactor, ethylene was charged at 35 bar, and the mixture was stirred at a stirring speed of 500 rpm. After one hour, the ethylene feed to the reactor was stopped, the stirring was stopped to stop the reaction, and the reactor was cooled to below 10 ° C. After the excess ethylene was discharged from the reactor, ethanol containing 10 vol% hydrochloric acid was injected into the liquid contained in the reactor. A small amount of organic layer sample was passed over silica gel, dried and analyzed by GC-FID. The remaining organic layer was filtered to separate the solid wax / polymer product. These solid products were dried in an oven at 80 DEG C for 8 hours and then weighed to obtain polyethylene. The results are shown in Table 1 below.

As shown in Table 1, the ethylene oligomerization reaction was carried out using the catalyst system according to the present invention. As a result, 1-hexene and 1-octene can be simultaneously produced at a high selectivity of 90 wt% or more, preferably 95 wt% or more. . It can be seen that when a specific ligand compound and a chromium compound are used in combination (Examples 2 and 3), they show excellent activity compared to the conventional (comparative example).

The preferred embodiments of the present invention have been described in detail above. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning, range, and equivalence of the claims are included in the scope of the present invention Should be interpreted.

Claims (7)

A ligand compound represented by the following formula (1); Chromium compounds; And a metal alkyl compound, in the presence of an olefin oligomerization catalyst system.
[Chemical Formula 1]

Wherein E1 and E3 are nitrogen (N) or phosphorus (P) and E2 and E4 are nitrogen (N), oxygen (O), phosphorus (P) or sulfur (S) At least one of them is nitrogen (N) or phosphorus (P), B1 is aluminum (Al) or boron (B), and R1 to R9 are each independently hydrogen or an alkyl (Alkyl) group having 1 to 20 carbon atoms. The method according to claim 1,
Wherein E1 in the formula (1) is nitrogen (N) and E2 is oxygen (O), E3 is nitrogen (N) and E4 is oxygen (O). The method according to claim 1,
Wherein the chromium compound is chromium (III) or chromium (II) containing compound. The method according to claim 1,
Wherein said olefin oligomerization comprises trimerization and quaternization. The method according to claim 1,
Wherein said olefin oligomerization reaction is carried out in a homogeneous liquid phase reaction. The method according to claim 1,
Wherein the olefin oligomerization reaction is carried out in an inert solvent that does not react with the catalyst compound. The method according to claim 1,
Wherein the olefin oligomerization reaction is carried out at a temperature of from 0 to 250 < 0 > C and a pressure of from 1 to 200 bar.