JP2622797B2 - Method for producing linear α-olefin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear α-polymer useful as a comonomer for producing polyolefin or a raw material for producing synthetic lubricating oil.
More specifically, the present invention relates to a method for producing a linear α-olefin having 10 or less carbon atoms, which has a high yield and a high purity α-olefin.

[0002]

2. Description of the Related Art Conventionally, ethylene has been polymerized in a solvent in the presence of a catalyst such as a zirconium-based catalyst comprising a zirconium component and an organoaluminum component, and has a carbon number of 4 to 20. It is known to produce a degree of linear α-olefin. Linear α-olefins having 4 to 8 carbon atoms are mainly used as comonomers for polyolefin production. In addition, carbon number 10
The following linear α-olefins have recently attracted attention as raw materials for producing synthetic lubricating oils. The demand for these linear α-olefins having 10 or less carbon atoms has increased in recent years as compared with linear α-olefins having 12 or more carbon atoms. However, in the conventional method, the yield of linear α-olefin having 10 or less carbon atoms was only about 60% by weight. For this reason, development of a production method with a high yield of linear α-olefins having 10 or less carbon atoms has been desired.

[0003]

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a result, the zirconium component and the organoaluminum component of the zirconium-based catalyst have a predetermined composition, and the polymerization reaction system It has been found that by maintaining a relatively high pressure, the yield of linear α-olefins having 10 or less carbon atoms can be increased, and the present invention has been completed based on this finding.

That is, the present invention provides a method for producing a linear α-olefin by polymerizing ethylene in an organic solvent in the presence of a zirconium-based catalyst comprising a zirconium component [A] and an organoaluminum component [B]. General formula [I] as zirconium component [A]

Embedded image (Wherein X represents a chlorine atom, bromine atom, iodine atom or alkoxy group, and A represents a chlorine atom, bromine atom, iodine atom or alkoxy group. They may be the same or different from each other. Further, k represents 0 or an integer in the range of 1 to 4.), and the general formula [II] is used as the organoaluminum component [B].

Embedded image (Wherein, R represents an alkyl group having 1 to 20 carbon atoms, Q represents a chlorine atom, a bromine atom, or an iodine atom. Then, m is selected from 0, 1, 1.5 and 2; Also, n is 1,
1.5, 2 and 3; and
m + n = 3. An organoaluminum compound (b) represented by the general formula [III]

Embedded image (In the formula, R ′ represents an alkyl group having 1 to 20 carbon atoms.)
And the molar ratio (b) / (a) between the organoaluminum compound (b) and the zirconium compound (a) in the organoaluminum component [B] is used. 10 or more, and the molar ratio (b) / (c) of the organoaluminum compound (b) to the organoaluminum compound (c) in the organoaluminum component [B] is in the range of 2 to 10, and 65 kg / cm ^2. G
A linear α characterized by conducting a polymerization reaction at the above pressure
The present invention provides a method for producing an olefin.

In the present invention, a zirconium-based catalyst comprising a zirconium component [A] and an organoaluminum component [B] is used as a catalyst, and ethylene is oligomerized to produce a linear α-olefin. Here, as the zirconium component [A] as the transition metal component, a zirconium compound (a) represented by the general formula [I] is used. In the general formula [I], X represents a chlorine atom, a bromine atom,
A represents an iodine atom or an alkoxy group, and A represents a chlorine atom, a bromine atom, an iodine atom or an alkoxy group, which may be the same or different from each other. The alkoxy group preferably has 1 to 20 carbon atoms. K represents 0 or an integer in the range of 1 to 4. Such zirconium compounds include, for example, ZrCl ₄ , ZrBr ₄ , ZrI ₄ , ZrBrCl
₃ , ZrBr ₂ Cl ₂ , Zr (OBu) ₄ , Zr (OC
H ₂ CH ₃ ) ₃ , Zr (OCH ₂ CH ₂ CH ₃ ) _{3 and the} like.
Preferably, rCl ₄ is used. One of these zirconium compounds may be used alone, or two or more thereof may be used in combination. OBu represents a butoxy group.

On the other hand, the organoaluminum component [B], which is another component of the catalyst of the present invention, includes an organoaluminum compound (b) represented by the above general formula [II] and an organoaluminum compound (b) represented by the above general formula [III]. It is necessary to use two kinds of organoaluminum compounds (c). Here, even when only the organoaluminum compound (b) represented by the general formula [II] is used, the catalytic activity is low,
On the other hand, even when only the organoaluminum compound (c) represented by the general formula [III] is used, only a polyethylene is produced, and a lower α-olefin cannot be obtained.

First, the organoaluminum compound (b) represented by the general formula [II] will be described. In the general formula [II], R represents an alkyl group having 1 to 20 carbon atoms, and among them, a methyl group , An ethyl group, a propyl group, and a butyl group are preferred, and an ethyl group is particularly preferred, but a mixture of two or more of these may be used. Also, Q
Represents a chlorine atom, a bromine atom, and an iodine atom, and any one of them may be used alone, or two or more of them may be mixed. Among these, a chlorine atom is preferred. Next, m is selected from 0, 1, 1.5 and 2, and n is selected from 1, 1.5, 2 and 3, and satisfies m + n = 3 Things.

Specific examples of the organoaluminum compound (b) represented by the general formula [II] include:
AlCl ₃ , AlBr ₃ , AlCl ₂ Br, Al (C _{2
H 5) Cl 2, Al (} C 2 H 5) Br 2, Al (C 2
_{H 5) I 2, Al (} C 2 H 5) 1.5 Cl 1.5, Al (C
_{2 H 5) 1.5 Br 1.5,} Al (C 2 H 5) 1.5 I 1.5,
Al (C ₃ H ₇ ) _1.5 Cl _1.5 , Al (iso-C ₃ H ₇ )
_1.5 Cl _1.5 , Al (C ₄ H ₉ ) _1.5 Cl _1.5 , Al
(Iso-C ₄ H ₉ ) _1.5 Cl _1.5 , Al (C ₆ H ₁₃ ) _1.5
Cl _1.5 , Al (C ₈ H ₁₇ ) _1.5 Cl _1.5 , Al (C _{2
H 5) 1.5 Br 0.5 Cl,} Al (C 2 H 5) (CH 3)
_0.5 Cl _1.5 , Al (C ₂ H ₅ ) ₂ Cl, Al (C ₂ H
₅ ) ₂ Br, Al (C ₂ H ₅ ) ₂ I and the like.
Among them, Al (C ₂ H ₅ ) _1.5 Cl _1.5 is particularly preferable. Further, when AlCl ₃ is used, the amount of by-produced polymer increases, but it is extremely inexpensive, so it is frequently used. As described above, the organoaluminum compound (b) represented by the general formula [II] may be used alone or in combination of two or more.

Next, the organoaluminum compound (c) represented by the general formula [III] will be described. In the general formula [III], R ′ represents an alkyl group having 1 to 20 carbon atoms, Group, ethyl group, propyl group,
A butyl group is preferred, and an ethyl group is particularly preferred, but two or more of these may be mixed. Examples of such an organoaluminum compound (c) represented by the general formula [III] include Al (CH ₃ ) ₃ , Al
(C ₂ H ₅ ) ₃ , Al (C ₃ H ₇ ) ₃ , Al (iso-C _{3
H 7) 3, Al (C} 4 H 9) 3, Al (iso-C 4 H 9)
_{3, Al (C 5 H 11} ) 3, Al (C 6 H 13) 3, Al
(C ₈ H ₁₇ ) _{3 and the} like. Among these, A
l (CH _{3) 3} and Al (C ₂ H _{5) 3} is preferable, in particular Al (C ₂ H _{5) 3} preferred. The general formula [II
One type of the organoaluminum compound (c) represented by I] may be used alone, or two or more types may be used in combination.

In the present invention, the above-mentioned catalyst components are basically used, but it is necessary to use such catalyst components in the following ratios. That is, the molar ratio (b) / (a) between the organoaluminum compound (b) and the zirconium compound (a) in the organoaluminum component [B] is 10 or more, preferably 15 or more. If the molar ratio is less than 10, the yield of linear α-olefins having 12 or more carbon atoms increases, which is not preferable. The molar ratio (b) / (c) of the organoaluminum compound (b) and the organoaluminum compound (c) in the organoaluminum component [B] is in the range of 2 to 10, preferably in the range of 3 to 4. And If the molar ratio is less than 2, the activity becomes high, but the amount of by-produced polymer increases, which is not preferable. On the other hand, when this molar ratio is more than 10,
Although the purity of the resulting linear α-olefin improves,
It is not preferable because the activity is reduced.

The zirconium catalyst used in the present invention is prepared from the zirconium component [A] and the organoaluminum component [B] as described above. In preparing the catalyst, a solvent is usually used. Examples of the solvent used herein include alicyclic hydrocarbon solvents such as cyclohexane and decalin, aliphatic hydrocarbon solvents such as pentane, hexane, heptane, octane, nonane, decane, dichloroethane and dichlorobutane, benzene, toluene and xylene. And aromatic hydrocarbon solvents such as chlorobenzene, ethylbenzene, dichlorobenzene, and chlorotoluene. Particularly, it is preferable to use an alicyclic hydrocarbon solvent.

In preparing the catalyst, a third component may be added as required. The third component includes at least one compound selected from a sulfur compound, a phosphorus compound, a nitrogen compound and an alcohol from the viewpoint of improving the purity of the α-olefin.

The sulfur compound may be any organic sulfur compound, and is not particularly limited. Examples thereof include thioethers such as dimethyl sulfide, diethyl sulfide and dipropyl sulfide, dimethyl disulfide, diethyl disulfide, dipropyl disulfide, and dipropyl disulfide. Dialkyl disulfide compounds such as dibutyl sulfide; thiophenes such as thiophene, 2,3-diethylthiophene and 2-ethylthiophene; heterocyclic sulfur compounds such as tetrahydrothiophene and thiopyran; aromatic sulfur compounds such as diphenyl sulfur and diphenyl disulfide Thiourea, sulfides such as methyl sulfide, ethyl sulfide and butyl sulfide. Among these, it is particularly preferable to use dimethyl disulfide, thiophene, and thiourea.

The phosphorus compound is not particularly limited as long as it is an organic phosphorus compound. For example, phosphines such as triphenylphosphine, triethylphosphine, tributylphosphine and trioctylphosphine are preferably used. Further, the nitrogen compound is not particularly limited as long as it is an organic nitrogen compound. For example, methylamine, ethylamine, propylamine, butylamine, aniline, benzylamine, diethylamine, dibutylamine, trimethylamine, triethylamine,
Organic amines such as tributylamine are exemplified. Among them, it is particularly preferable to use aniline. Examples of the alcohol include methanol, ethanol, and propanol. The use ratio of these third components is usually 0.1 to 6 mol per 1 mol of the zirconium compound (a) of the zirconium component [A].

In the present invention, ethylene is polymerized using the above-mentioned catalyst. The polymerization reaction is performed in an organic solvent. As the organic solvent, for example, various solvents such as alicyclic hydrocarbon solvents, aromatic hydrocarbon solvents, and aliphatic hydrocarbon solvents can be used. It is particularly preferable to use an aliphatic hydrocarbon solvent. Examples of such a solvent include the same solvents as those used in the preparation of the catalyst described above.

In the present invention, such an organic solvent 2
Usually, the zirconium component [A] in the catalyst prepared by the above method is 0.01 to 0.25 mmol per 50 ml,
Preferably, a catalyst contained in a ratio of 0.02 to 0.1 mmol is used.

The polymerization temperature is usually from 90 to 150.
° C, preferably 100 to 130 ° C. If the polymerization temperature is too low, undesired poly-α-olefin tends to precipitate during polymerization, which is not preferable. On the other hand, if the polymerization temperature is too high, the amount of generated impurities is undesirably increased.
Next, in the present invention, the polymerization pressure needs to be 65 kg / cm ² G or more, preferably 90 kg / cm ² G or more.
If the polymerization pressure is lower than 65 kg / cm ² G, the by-products increase and the purity of the product decreases.

Since the polymerization time varies depending on the polymerization temperature and the polymerization pressure, it cannot be determined uniformly, but usually about 10 minutes to 1 hour is sufficient. After completion of the polymerization reaction, the reaction product may be adiabatically flashed to remove unreacted ethylene, then subjected to a catalyst deactivation treatment, and the solvent and various linear α-olefins may be separated by distillation. Unreacted ethylene and the solvent are usually recycled to the reaction system. Here, the catalyst deactivation treatment may be performed, for example, by adding deactivation such as amines or aqueous ammonia to the reaction product liquid. As described above, the desired linear α-olefin can be produced.

[0019]

Next, the present invention will be described in detail with reference to examples. Example 1 (1) Preparation of Catalyst Suspension In a 500-ml flask equipped with a stirrer, under an argon atmosphere, 25 mmol of anhydrous zirconium tetrachloride as the organic zirconium compound (a) and 250 ml of dry cyclohexane were added. Then, trimethylaluminum [Al (CH ₃ ) ₃ ] is added as the organoaluminum compound (c), and then ethylaluminum sesquichloride [Al (C ₂ H ₅ ) _1.5 Cl _1.5 ] is added as the organoaluminum compound (b). Was added. In addition, each addition amount was adjusted to the molar ratio shown in Table 1. Thereafter, the mixture was stirred at 70 ° C. for 3 hours to prepare a catalyst suspension.

(2) Ethylene Oligomerization Reaction Under an argon atmosphere, 250 ml of dry cyclohexane was introduced into a 1-liter autoclave equipped with a stirrer, and then the catalyst suspension containing 0.1 mmol as a zirconium component was added. The liquid was introduced. Next, after the temperature was raised to 120 ° C. while stirring, ethylene was rapidly blown in, and the pressure of the autoclave was increased to 65 kg / cm ² G
Maintained. After performing the reaction for 30 minutes under these reaction conditions, aqueous ammonia was added as an inactivator into the autoclave, cooled, and depressurized. The reaction product was processed according to the following procedure. The product liquid remaining in the autoclave was taken out, 20 g of n-undecane, an internal standard substance for gas chromatography, was added, and the wax was filtered off using a filter paper. The obtained filtrate was analyzed by gas chromatography. Incidentally, C ₄ -C ₈ fraction, since the volatile to loss is inevitable during the process, these resulting rate was estimated from the Schulz-Flory distribution. The wax content was added to the yield of a fraction having 12 or more carbon atoms (C ₁₂ ⁺ fraction). C ₄ -C respective fractions of up to ₁₀ and having 12 or more fractions carbon each resulting ratio of (C ₁₂ ⁺ fraction) are shown in Table 1. The "product purity" in Table 1 indicates the ratio of linear α-olefins in the same carbon fraction, and the "product yield" of each fraction.
Indicates the proportion of each fraction in the total product.

Example 2 (1) Preparation of catalyst suspension Triethylaluminum was used instead of trimethylaluminum, and organoaluminum compound (b) was used.
A catalyst suspension was prepared in the same manner as in Example 1, except that the amount of (c) added was adjusted to the molar ratio shown in Table 1. (2) Ethylene oligomerization reaction An oligomerization reaction was performed in the same manner as in Example 1 except that the catalyst suspension obtained in the above (1) was used. Table 1 shows the results.

Example 3 (1) Preparation of Catalyst Suspension Example 2 was prepared in the same manner as in Example 2 except that the amounts of the organoaluminum compounds (b) and (c) were adjusted to the molar ratios shown in Table 1. Similarly, a catalyst suspension was prepared. (2) Ethylene oligomerization reaction The oligomerization reaction was carried out in the same manner as in Example 2 except that the catalyst suspension obtained in the above (1) was used and the reaction pressure was set to 90 kg / cm ² G. Done. Table 1 shows the results.

Comparative Example 1 (1) Preparation of Catalyst Suspension Example 2 was prepared in the same manner as in Example 2 except that the amounts of the organoaluminum compounds (b) and (c) were adjusted to the molar ratios shown in Table 1. Similarly, a catalyst suspension was prepared. (2) Ethylene oligomerization reaction An oligomerization reaction was carried out in the same manner as in Example 2 except that the catalyst suspension obtained in the above (1) was used. Table 1 shows the results.

Comparative Example 2 An oligomerization reaction was carried out in the same manner as in Example 3 except that the catalyst suspension prepared in the same manner as in Example 3 was used and the reaction pressure was set to 50 kg / cm ² G. Was. Table 1 shows the results.

Example 4 (1) Preparation of Catalyst Suspension As the organoaluminum compound (c), triethylaluminum was used in place of trimethylaluminum, and the addition amount of the organoaluminum compounds (b) and (c) was changed. The molar ratio is adjusted to the value shown in Table 1, and zirconium tetrabutoxide [Zr (OC ₄ H ₉ )] is used as the zirconium compound instead of anhydrous zirconium tetrachloride.
_A catalyst suspension was prepared in the same manner as in Example 1 except that ₄ ) was used. (2) Ethylene oligomerization reaction An oligomerization reaction was performed in the same manner as in Example 1 except that the catalyst suspension obtained in the above (1) was used. Table 1 shows the results. When zirconium tetrabutoxide was used as the zirconium compound, a larger amount of polyethylene (by-product polymer) was generated than when zirconium halide such as zirconium tetrachloride was used.

[0026]

[Table 1]

* 1: TMA = trimethyl aluminum TEA = triethyl aluminum * 2: EASC = ethyl aluminum sesquichloride

[0028]

According to the method of the present invention, by using a specific catalyst and increasing the polymerization pressure to 65 kg / cm ² G or more, the yield of linear α-olefin having 10 or less carbon atoms can be reduced to 70% by weight. This can be extremely large. Moreover, according to the method of the present invention, the purity of the obtained linear α-olefin is high. The linear α-olefin obtained by the method of the present invention is useful as a comonomer for producing a polyolefin or a raw material for producing a synthetic lubricating oil. Therefore, the present invention can be effectively used in the field of polyolefin production, the field of synthetic lubricating oil production, and the like.

[Brief description of the drawings]

FIG. 1 is a drawing showing a process for preparing a catalyst used in the method of the present invention.

Claims (1)

(57) [Claims] 1. A method for producing a linear α-olefin by polymerizing ethylene in an organic solvent in the presence of a zirconium-based catalyst comprising a zirconium component [A] and an organoaluminum component [B]. A] has the general formula [I] (Wherein X represents a chlorine atom, bromine atom, iodine atom or alkoxy group, and A represents a chlorine atom, bromine atom, iodine atom or alkoxy group. They may be the same or different from each other. Further, k represents 0 or an integer in the range of 1 to 4.) and a zirconium compound (a) represented by the following general formula [II]: ] (Wherein, R represents an alkyl group having 1 to 20 carbon atoms, Q represents a chlorine atom, a bromine atom, or an iodine atom. Then, m is selected from 0, 1, 1.5 and 2; Also, n is 1,
1.5, 2 and 3; and
m + n = 3. An organoaluminum compound (b) represented by the formula (III): (In the formula, R ′ represents an alkyl group having 1 to 20 carbon atoms.)
And the molar ratio (b) / (a) between the organoaluminum compound (b) and the zirconium compound (a) in the organoaluminum component [B] is used. 10 or more, and the molar ratio (b) / (c) of the organoaluminum compound (b) to the organoaluminum compound (c) in the organoaluminum component [B] is in the range of 2 to 10, and 65 kg / cm ^2. G
A linear α characterized by conducting a polymerization reaction at the above pressure
-Method for producing olefins.