JP2002121157A - Method for producing alpha-olefin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an α-olefin, by which the highly pure α-olefin containing the linear α-olefin in a high concentration can be obtained in the presence of a zirconium-based complex catalyst. SOLUTION: This method for producing the α-olefin, characterized by oligomerizing ethylene in the presence of a zirconium-based complex catalyst comprising an organic aluminum and a zirconium halide represented by the general formula (1): ZrX1nX24-n...(1) [X1 and X2 are each chlorine atom, bromine atom, iodine atom or fluorine atom; (n) is an integer of 0 to 4], characterized by using a compound having an ionization potential of <=9 eV as the third component of the catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an .alpha.-olefin, and more particularly, to a method for producing an .alpha.-olefin useful as a raw material for a polyolefin-modified monomer, a synthetic lubricating oil, a plasticizer and a surfactant. About.

[0002]

2. Description of the Related Art Linear α-olefins have a straight-chain molecular structure without branching and have 4 to 4 carbon atoms having a terminal double bond.
About 20 olefins. High-purity α-olefins, especially high-purity α-olefins containing a high concentration of linear α-olefins, are useful as polyolefin reforming monomers or as raw materials for synthetic lubricating oils, plasticizers and surfactants.

As a method for producing an α-olefin, a method for oligomerizing ethylene is known, and there are methods for producing an α-olefin having a Schulz-Flory distribution and an α-olefin having a Poisson distribution. As a method for producing an α-olefin having a Poisson distribution, there is a two-step method (growth reaction-exchange reaction) using a trialkylaluminum, but the purity of the linear α-olefin becomes low.

One of the methods for producing an α-olefin having a Schulz-Flory distribution is to use a zirconium-based complex catalyst.
-High-purity α-olefins containing a small amount of olefins and containing a large amount of linear α-olefins can be obtained, but depending on the application, highly pure α-olefins containing a higher concentration of linear α-olefins are eagerly desired. . In order to improve the purity, a method of adding various ligands as a third component has been proposed (for example, Japanese Patent Publication No. 6-78373).
JP, JP-A-6-293670, JP-A-7-3
No. 30633, JP-A-7-330634, etc.), the effect was not sufficient.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and uses a zirconium-based complex catalyst.
An object of the present invention is to provide a method for producing an α-olefin capable of obtaining a high-purity α-olefin containing a high concentration of linear α-olefin.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have achieved the above object of the present invention effectively by using a compound having an ionization potential of 9 eV or less as the third component of the catalyst. The present invention has been accomplished by finding out what can be achieved. That is, the gist of the present invention is:
It is as follows. 1. The following general formula _{^{(1) ZrX 1 n X 2}} 4-n ··· (1) ( wherein, X ¹ and X ² are each a chlorine atom, a bromine atom, an iodine MotoHara Komata represents a fluorine atom, n represents 0 When an ethylene oligomerization reaction is carried out using a zirconium-based complex catalyst comprising a zirconium halide and organoaluminum represented by the following formula: a compound having an ionization potential of 9 eV or less as a third component of the catalyst. A method for producing an α-olefin, characterized by using 2. 2. The method for producing an α-olefin according to the above 1, wherein the compound having an ionization potential of 9 eV or less is at least one selected from a polycyclic aromatic compound and a hetero compound. 3. 3. The method for producing an α-olefin according to the above 1 or 2, wherein the zirconium halide is zirconium tetrachloride. 4. 4. The method for producing an α-olefin according to any one of the above items 1 to 3, wherein the organic aluminum comprises triethylaluminum and ethylaluminum sesquichloride.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The zirconium halide of the catalyst used in the present invention is represented by the general formula (1). Specifically, Z
rCl ₄ , ZrBr ₄ , ZrI ₄ , ZrBrCl ₃ , Z
Examples thereof include rBr ₂ Cl ₂ and ZrBr ₃ Cl, which may be used alone or in combination of two or more. Among them, ZrCl ₄ is preferable. The zirconium halide may contain a trace amount of impurities such as hafnium (Hf).

[0008] Next, the organic aluminum used as co-catalyst, the following general formula ^{_{(2) AlR m X 3 3}} -m ··· (2) where, R represents an alkyl group having 1 to 20 carbon atoms shows, X ³
Represents a chlorine atom, a bromine atom, an iodine atom or a halogen atom of a fluorine atom, and m is 1, 1.5, 2 or 3.
(3-m) pieces of X ³ may be a halogen atom, respectively same or different. When m is 1.5, AlR _1.5
X ³ _1.5 . Such compounds are not present in theory, usually, it is conventionally expressed as sesquicarbonate of Al ₂ R ^₃ X _{3 3.}

Specific examples of these organic aluminums include:
Has Al (CH_Three)_Three, Al (C _TwoH_Five)_Three(Less than,
Sometimes abbreviated as TEA. ), Al (n-C
_ThreeH₇)_Three, Al (iso-C_ThreeH₇)_Three, Al (n-
C_FourH₉)_Three, Al (iso-C_FourH₉)_Three, Al (C
_FiveH₁₁)_Three, Al (C₆H₁₃)_Three, Al (C
₈H₁₇)_Three, Al (CH_Three)_TwoCl, Al (C_TwoH_Five)
_TwoCl, Al (C_TwoH_Five)_TwoBr, Al (C _TwoH_Five)_Two
I, Al (C_TwoH_Five)_TwoF, Al (n-C_ThreeH₇)_TwoC
1, Al (iso-C_ThreeH₇)_TwoCl, Al (n-C_Four
H₉)_TwoCl, Al (iso-C_FourH ₉)_TwoCl, Al
(C_FiveH₁₁)_TwoCl, Al (C₈H₁₇)_TwoCl and others
I can do it.

In addition, Al (C_TwoH_Five) Cl_Two, Al (C
_TwoH_Five) Br_Two, Al (C_TwoH_Five) I_Two, Al (C_TwoH
_Five) F_Two, Al (n-C_ThreeH₇) Cl_Two, Al (iso
-C _ThreeH₇) Cl_Two, Al (n-C_FourH₉) Cl_Two, A
l (iso-C_FourH₉) Cl _Two, Al (C_FiveH₁₁) Cl
_Two, Al (C₈H₁₇) Cl_Two, Al_Two(CH_Three)_ThreeCl
_Three, Al_Two(CH_Three)_ThreeBr_Three, Al_Two(C_TwoH_Five)_Three
Cl_Three(Hereinafter, it may be abbreviated as EASC.), Al
_Two(C_TwoH_Five)_ThreeBr_Three, Al_Two(C_TwoH_Five) _ThreeI_Three,
Al_Two(N-C_ThreeH₇)_ThreeCl_Three, Al_Two(Iso-C
_ThreeH₇)_ThreeCl _Three, Al_Two(N-C_FourH₉)_ThreeCl_Three,
Al_Two(Iso-C_FourH₉)_ThreeCl_Three, Al_Two(C_FiveH
₁₁)_ThreeCl_Three, Al_Two(C₈H₁₇)_ThreeCl_ThreeEtc.
Can be In addition, these organic aluminums
Even if used alone, use a combination of two or more
Is also good. Above all, use TEA and EASC in combination
Is preferred. In that case, EASC / TEA (mol
Ratio) is preferably adjusted to 1.5 to 15.

In the present invention, a compound having an ionization potential of 9 eV or less is added as the third component to the above catalyst. This ionization potential is calculated by molecular orbital calculation M
The parameter is a value calculated by PM3 using OPAC97. The compound having an ionization potential of 9 eV or less is not particularly limited, but is preferably selected from a polycyclic aromatic compound and a hetero compound.

As polycyclic aromatic compounds, anthracene,
Examples thereof include phenanthrene, fluorene, fluoranthene, or an alkylated product thereof, or an alkylated diphenyl compound. Examples of the hetero compound include hydrothiophene, diethyl disulfide, dimethyl disulfide, thianthrene, tetrahydrofulvalene, benzothiophene, dibenzothiophene, and alkylated products thereof.

The alkyl group of the above-mentioned alkylated polycyclic aromatic compound and hetero compound has 1 to 18 carbon atoms.
And the number of substitution of the alkyl group is not particularly limited. Further, it may be substituted with an alkoxy group such as an ethoxy group together with the alkyl group. The amount of the third component to be added is preferably 0.5 to 10 times the mol of the zirconium halide. If the molar ratio is less than 0.5 times, a sufficient improvement in purity cannot be expected.
Even if it exceeds twice the molar amount, an effect commensurate with the amount cannot be expected.
More preferably, it is 1 to 8 moles.

These third components may be added to the catalyst during the preparation of the catalyst, or may be added directly to the reaction system for oligomerization, but the effect is obtained in a smaller amount when added during the preparation of the catalyst. It is preferred. The case where the third component is added during the preparation of the catalyst will be described below.

The catalyst is prepared by contacting the above zirconium halide, organoaluminum and the third component in an inert solvent. As an inert solvent,
Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, chlorobenzene, dichlorobenzene, and chlorotoluene or their halogen-substituted products; aliphatic hydrocarbons such as pentane, hexane, heptane, octane, nonane, and decane; cyclohexane and decalin; Examples thereof include alicyclic hydrocarbons and halogenated hydrocarbons such as dichloroethane and dichlorobutane. In the case where an aromatic hydrocarbon solvent is used, an aliphatic hydrocarbon solvent or an alicyclic hydrocarbon solvent is preferable because the solvent may be mixed in a product in some cases.

The concentration of zirconium halide and organoaluminum at the time of preparation of the catalyst is as follows:
10 to 200 mmol, preferably 20 to 150 mmol, of zirconium halide and 25 of organoaluminum
2,000 mmol, preferably 50-1,200 mmol. From the viewpoint of catalytic activity, organoaluminum / zirconium halide (molar ratio) [Al
/ Zr (molar ratio). ] Is preferably set to 2 to 15.

The contact of each component may be performed under stirring at 60 to 80 ° C. for 10 minutes to 2 hours under an atmosphere of an inert gas such as argon. In the present invention, an ethylene oligomerization reaction is carried out using the catalyst prepared as described above. The amount of the catalyst used is usually diluted with the above-mentioned inert solvent, and the zirconium compound is added in an amount of 0.1 per liter of the above-mentioned inert solvent.
２2 mmol.

[0018] The reaction temperature is usually in the range of 80 to 150 ° C, preferably 100 to 130 ° C. The reaction pressure is usually 0.5 MPa (G) or more, preferably 2.5 MPa (G).
(G) and above. The reaction time is generally in the range of 5 minutes to 2 hours, preferably 15 minutes to 1 hour 30 minutes. Ethylene may be continuously supplied so as to maintain the above-mentioned pressure, or may be sealed at the above-mentioned pressure at the start of the reaction to react. Ethylene as a raw material gas may contain a gas inert to the reaction, for example, nitrogen, argon, helium, or the like. Note that all operations from the preparation of the catalyst to the end of the oligomerization reaction are desirably performed in an atmosphere of an inert gas such as argon while avoiding air and moisture.

This reaction can be carried out in any of a batch system, a semi-continuous system and a continuous system. After completion of the oligomerization reaction, the reaction product is adiabatically flushed to remove unreacted ethylene, and the reaction solution is deactivated with water, alcohol, aqueous sodium hydroxide, or the like. After removing the by-product wax and the deactivated catalyst, the formed α-olefin is separated from the reaction solution by a known extraction method or distillation method.

[0020]

[Example 1]

(1) Preparation of catalyst Under an argon atmosphere, a zirconium tetrachloride (ZrCl
₄ ) 25 mmol and 250 ml of dry cyclohexane were introduced and stirred for 10 minutes. To this, 38.89 mmol of triethylaluminum (TEA) was added, and after stirring for 10 minutes, 136.11 mmol of ethylaluminum sesquichloride (EASC) [(EAS
C + TEA) / ZrCl ₄ (molar ratio) 7, EASC / T
EA (molar ratio) 3.5] was added thereto, and a zirconium complex as a catalyst was formed with stirring at 70 ° C. for 1 hour. The catalyst solution turned grayish green after complex formation. To this, 125 mmol of anthracene was added as a third component, and the mixture was stirred at room temperature for 30 minutes.

(2) Ethylene oligomerization reaction Under a dry argon atmosphere, 250 ml of dried cyclohexane and a predetermined amount of undecane as an internal standard substance were added to a 1-liter autoclave equipped with a stirrer. To 0.1 mmol as ZrCl ₄ . When the addition was completed, the temperature of the autoclave was raised to 130 ° C., and the dried ethylene was passed through a regulator to a reaction pressure of 6.5 MPa.
I stuck all at once until it reached a (G). Thereafter, a sample was taken out every 10 minutes and reacted for 1 hour. During this time, ethylene was continuously charged to keep the reaction pressure constant.
That is, in order to keep the reaction pressure constant during the reaction, ethylene was constantly charged with a regulator.

In addition, at the time of sampling every 10 minutes, in order to prevent a decrease in purity due to a decrease in reaction pressure, the product liquid was immediately deactivated from a reactor in a 1N aqueous sodium hydroxide solution at a high pressure. This sampling was performed every 10 minutes, and a total of six tubes were collected in 60 minutes. These samples were washed with water, the solids were filtered off, and then subjected to analysis. Since light fraction loss of C ₄ fraction such unavoidable experimentation, Schultz-from C ₈ -C yield of ₂₀ fractions undecane reference internal standard
C ₄ fraction, the yield of C ₆ fraction obtained using the Flory distribution, was determined yield. Further, the decrease in the purity of the α-olefin is due to the reaction of the α-olefin produced in the reaction and by-products. For example, (1-octadecene concentration (mass% of C ₁₈ distillate)) Purity of C ₁₈ fraction is related to the yield of C ₄ -C ₁₆ fraction α- olefins produced by the reaction,
If this amount is large, the reaction of these olefins leads to
_The purity of the fraction ₁₈ decreases.

Thus, α-olefin purity, for example, C
The purity of the ₁₈ fraction relates to the yield of C ₄ -C ₁₆ α-olefins produced under the same reaction conditions (temperature and pressure). And no accurate purity improvement effect is seen. Therefore, in Table 1, a line of the yield of the C ₄ -C ₁₆ fraction versus the C ₁₈ fraction of the sample every 10 minutes is drawn, and the C ₁₈ fraction when the yield of the C ₄ -C ₁₆ fraction is 75 g is drawn. Was shown.

Examples 2 to 6, Comparative Examples 1 to 3
, An ethylene oligomerization reaction was carried out in the same manner except that the third component shown in Table 1 was added instead of anthracene. The results are shown in Table 1.

Reference Example 1 An ethylene oligomerization reaction was carried out in the same manner as in Example 1 except that the third component was not added. The results are shown in Table 1.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

According to the present invention, there is provided a method for producing an α-olefin capable of obtaining a high-purity α-olefin containing a linear α-olefin at a high concentration using a zirconium-based complex catalyst. Can be.

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Claims (4)

[Claims] 1. The following general formula (1): ZrX ¹ _n X ² _4-n (1) wherein X ¹ and X ² each represent a chlorine atom, a bromine atom, an iodine atom or a fluorine atom. And n represents an integer of 0 to 4.) When an ethylene oligomerization reaction is carried out using a zirconium-based complex catalyst comprising zirconium halide and organoaluminum represented by the following formula, ionization potential is used as a third component of the catalyst. Using a compound having a molecular weight of 9 eV or less. 2. The method for producing an α-olefin according to claim 1, wherein the compound having an ionization potential of 9 eV or less is at least one selected from a polycyclic aromatic compound and a hetero compound. 3. The method for producing an α-olefin according to claim 1, wherein the zirconium halide is zirconium tetrachloride. 4. The method according to claim 1, wherein the organoaluminum comprises triethylaluminum and ethylaluminum sesquichloride.