JP2001233913A - Manufacturing method of linear alpha olefin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a highly pure linear α-olefin in good producibility. SOLUTION: In a method of manufacturing a linear α-olefin by polymerizing ethylene in the presence of a catalyst, the method of manufacturing a linear α-olefin uses the catalyst wherein a preliminarily prepared catalyst comprising the combination of a zirconium compound and an aluminum compound as the catalyst is heat-treated at 90150 deg.C for 1-15 min.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a linear α-olefin. More specifically, the present invention relates to a method for producing a linear α-olefin capable of producing a highly pure linear α-olefin with high productivity.

[0002]

2. Description of the Related Art Linear α-olefins are highly useful compounds in a wide variety of fields such as polyolefin production, synthetic lubricating oils and surfactants. This linear α-olefin is generally produced by low-polymerizing ethylene in the presence of a catalyst. As a catalyst used for the low polymerization of ethylene, a known catalyst for ethylene polymerization is used.

By the way, various products using this linear α-olefin as a raw material, for example, alcohols for plasticizers, comonomers for polyolefins, synthetic lubricating oils, alcohols for surfactants, alkylbenzenes, α-olefinsulfonic acids, etc. Although widely used, these products are required to be of high quality. In particular, C ₆ alpha-olefins and C ₈ alpha-olefin comonomer for polyolefins reforming been increasingly high purity required in order to maintain a high activity of the catalyst during performance and polyolefin production of polyolefins ing. In order to meet such a demand, there is a demand for the development of a method for producing a linear α-olefin as a raw material having a higher purity than that obtained by a conventional method.

In the process of producing the linear α-olefin, the linear α-olefin is produced by low-polymerizing ethylene in the presence of a catalyst. It is considered that the purity of the linear α-olefin is reduced by further reacting to form a by-product. From this point of view, as a method of producing a high-purity linear α-olefin, a sulfur compound, a phosphorus compound, a nitrogen compound or alcohol is added to an ethylene polymerization catalyst to reduce the ethylene content. Methods for performing polymerization are known.

However, in these methods,
Although the purity can be improved to some extent, in order to maintain the purity, it is necessary to keep the concentration of the linear α-olefin in the low polymerization reactor low, which leads to a decrease in productivity and purification of the product. There is a disadvantage that the separation of additives in the process requires a great deal of expense.

[0006]

An object of the present invention is to provide a method for producing a linear α-olefin with high purity and high productivity.

[0007]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, as a catalyst for low polymerization of ethylene, a zirconium compound having a specific chemical structure and two aluminum compounds It was found that the above-mentioned object can be achieved by using a catalyst obtained by preliminarily preparing a catalyst component consisting of a predetermined molar ratio and then performing a heat treatment for a predetermined time in a predetermined temperature range. Based on this, the present invention has been completed.

That is, the gist of the present invention is as follows. (1) In a method for producing a linear α-olefin by low polymerization of ethylene in the presence of a catalyst, the catalyst comprises:
(A) The following general formula [1],

[0009]

Embedded image

[In the formula (1), X is each independently a chlorine atom,
A represents a bromine atom or an iodine atom, and A represents an alkoxy group having 1 to 4 carbon atoms. k is 0 or an integer of 1 to 4. A zirconium compound represented by the following general formula [2]:

[0011]

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[In the formula [2], R ¹ represents an alkyl group having 1 to 20 carbon atoms, and Q represents a chlorine atom or an iodine atom.
m is any of 1, 1.5 and 2. An aluminum compound represented by the following general formula [3]:

[0013]

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[In the formula [3], R ² represents an alkyl group having 1 to 20 carbon atoms. Wherein the content of each of these catalyst components is represented by the following formula in a molar ratio:

[0015]

(Equation 2)

A method for producing a linear α-olefin, characterized by using a catalyst obtained by further heating the pre-prepared catalyst at 90 to 150 ° C. for 1 to 15 minutes. (2) The pre-preparation of the catalyst is carried out by dissolving each catalyst component in a solvent, and the concentration of the component (a) is adjusted to 50 to 200 mmol per liter of the solvent. -A process for producing olefins. (3) In the preliminary preparation of the catalyst, the contact order of the catalyst components is prepared by first bringing the component (a) into contact with the component (c) and then bringing the component (b) into contact therewith. Or the method for producing a linear α-olefin according to (2). (4) The preliminary preparation of the catalyst is carried out at 60-70 ° C. for 0.5
The above (1) to (3), which are performed by maintaining for up to 3 hours.
The method for producing a linear α-olefin according to any one of the above. (5) A pre-prepared catalyst or a catalyst obtained by diluting the catalyst,
The method for producing a linear α-olefin according to any one of the above (1) to (4), further using a catalyst obtained by heating at 90 to 140 ° C. for 1 to 10 minutes.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a method for producing a linear α-olefin by low polymerization of ethylene in the presence of a catalyst, wherein the catalyst is represented by (a) represented by the aforementioned general formula [1]. A zirconium compound; (b) an aluminum compound represented by the general formula [2]; and (c) a trialkylaluminum compound represented by the following general formula [3]. Each of the catalyst components satisfies the above formula. The pre-prepared catalyst was further added at 90 to 150 ° C. for 1 to 1
This is a method for producing a linear α-olefin using a catalyst obtained by heating for 5 minutes.

The zirconium compound represented by the above general formula [1], which is the component (a) of the catalyst, has an alkoxy group having 1 to 4 carbon atoms represented by A in the general formula [1]: Examples include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an i-butoxy group, a sec-butoxy group, and a t-butoxy group.

Specific examples of the zirconium compound represented by the general formula [1] include, for example, zirconium tetrachloride, zirconium tetraiodide, tetraethoxy zirconium, tetra n-propoxy zirconium, tetraisopropoxy zirconium, tetra n -Butoxyzirconium and the like.

Next, the aluminum compound represented by the general formula [2], which is the component (b) of this catalyst, is an alkyl group having 1 to 20 carbon atoms represented by R ¹ in the general formula [2]. Represents a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an i-butyl group, s
ec-butyl group, t-butyl group, n-pentyl group, n-
Hexyl group, n-peptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n- Hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, n-eicosyl group and the like can be mentioned.

Specific examples of the aluminum compound (b) include, for example, ethyl aluminum sesquichloride, diethyl aluminum chloride, ethyl aluminum dichloride, dimethyl aluminum chloride, diisopropyl aluminum chloride,
Isopropyl aluminum sesquichloride and the like.

The trialkylaluminum compound represented by the general formula [3], which is the component (c) of the catalyst, has 1 to 3 carbon atoms represented by R ² in the general formula [3].
Examples of the alkyl group 20 include the same alkyl groups as those represented by R ¹ above.

Specific examples of the aluminum compound as the component (c) include triethylaluminum, trimethylaluminum, tri-n-butylaluminum, tri-t-butylaluminum and the like.

Next, the content ratio of each of these catalyst components in the catalyst is determined by comparing the usage ratio of the two types of aluminum compounds, that is, the usage ratio of component (b) and component (c), to 0 in terms of their molar ratios. 0.5 to 15. When the molar ratio is less than 0.5, the amount of the produced polymer increases, and when the molar ratio exceeds 15, the yield of the target linear α-olefin decreases. Because it becomes.

As for the usage ratio of the zirconium compound and the two kinds of aluminum compounds, the mole ratio of the sum of the components (b) and (c) and the component (a) is 2 to 2 in their molar ratios. 20. If this molar ratio is less than 2, the catalytic activity will decrease, leading to a decrease in the yield of linear α-olefins.
This is because, when the ratio exceeds 1, the obtained linear α-olefin has a product distribution with a large amount of light components.

The catalyst used in the present invention is obtained by preliminarily preparing the above catalyst components and then heat-treating the catalyst. At the time of the preparatory preparation of the catalyst, the above catalyst components are used. The dissolution is performed in a solvent. As the solvent that can be used here, alicyclic hydrocarbon solvents such as cyclohexane and decalin, and solvents such as pentane, hexane, heptane, octane, dichloroethane, and aliphatic hydrocarbons such as dichlorobutane and halides thereof, Examples thereof include aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, chlorobenzene, dichlorobenzene, and chlorotoluene, and solvents such as halides thereof. Among these solvents, solvents such as alicyclic hydrocarbon solvents, aliphatic hydrocarbons, and their halides are more preferable because they are less likely to be mixed into products.

Further, when the above catalyst components are brought into contact with each other in this solvent, it is preferred that the zirconium compound as the component (a) and the trialkylaluminum compound as the component (c) be brought into contact first. this is,
This is because if the zirconium compound as the component (a) is brought into contact with the aluminum compound as the component (b) first, the activity of the obtained catalyst may be reduced. Further, the order of adding each of these catalyst components to the solvent is as follows: first, the trialkylaluminum compound as the component (c) is added to the solvent;
After completely removing the water in the solvent, it is preferable to add the zirconium compound as the component (a) and finally add the aluminum compound as the component (b).

The concentration of the zirconium compound as component (a) per liter of the solvent is preferably in the range of 20 to 200 mmol per liter of the solvent. If the zirconium compound is less than 20 mmol, the storage stability of the catalyst may be reduced, and if the zirconium compound exceeds 200 mmol, heavy components in the product during low polymerization of ethylene may be produced. Is increased.

Furthermore, the temperature at the time of pre-preparation of this catalyst is 6
The temperature is preferably in the range of 0 to 80 ° C. This temperature is 60
If the temperature is lower than 80 ° C., the storage stability of the catalyst may decrease, and if the temperature is higher than 80 ° C., the generation ratio of heavy components in the reaction product may increase. . The aging time in this temperature range may be appropriately determined within a range of 30 minutes to 3 hours and 10 minutes.

Next, the catalyst thus preliminarily prepared is further subjected to 90-150 ° C., preferably 90-140 ° C.
A catalyst obtained by heating at 1 ° C. for 1 to 15 minutes, preferably 1 to 10 minutes is used. The heat treatment under such conditions is performed when the heat treatment temperature is lower than 90 ° C. or when the heat treatment time is less than 1 minute. α-
If the heat treatment temperature is higher than 150 ° C. or the heat treatment time exceeds 15 minutes, the weight of the reaction product by the obtained catalyst may be reduced. This is because the production ratio of the mass increases, which may cause a decrease in the yield of the linear α-olefin having the desired number of carbon atoms.

In the process of the present invention, a linear α-olefin is produced by carrying out a low-polymerization reaction of ethylene using the catalyst obtained as described above. The reaction temperature in this case is 80 to 150 ° C, preferably 100 to 120 ° C.
And If the reaction temperature is lower than 80 ° C., the catalytic activity is not sufficiently exhibited, and a high molecular weight polymer may be formed. If the reaction temperature is higher than 150 ° C., the catalyst may be deactivated or the product may be decomposed. This may cause an increase in the weight of heavy materials.

The pressure in this reaction is as follows:
The pressure is 2 to 8 MPa, preferably 3.5 to 7 MPa. When the pressure is less than 2 MPa, the amount of the raw material ethylene dissolved in the reaction solvent is reduced, and the selectivity to the linear α-olefin may be reduced. Polymerization also takes place in the gas phase in the vessel, resulting in a linear α
-The selectivity to olefins may be reduced.

During this reaction period, it is preferable to continuously charge the raw material ethylene while maintaining a constant pressure. After a predetermined reaction period, a catalyst deactivator such as an aqueous alkali solution or an aqueous methanol solution containing alkali is added to the reactor to stop the low polymerization reaction. In this way, a linear α-olefin that is a low-polymer of ethylene having 4 to 18 carbon atoms as a main component is obtained.

[0034]

[Example 1]

(1) Preliminary preparation of catalyst In an argon atmosphere, 25 mmol of anhydrous diconium tetrachloride (ZrCl ₄ ) as a component (a) and 250 ml of dry cyclohexane as a solvent were placed in a flask equipped with a stirrer having an internal volume of 500 ml under an argon atmosphere. And stirred for 10 minutes.

Then, 38.9 mmol of triethylaluminum was added thereto as the component (c) of the catalyst, and about 1
After stirring for 0 minutes, 136.1 mmol of ethyl aluminum sesquichloride was added as the component (b) of the catalyst,
The mixture was heated to 70 ° C. and stirred for 1 hour to form a complex. After the complex formation, the catalyst solution turned grayish green. In this case, the molar ratio of each catalyst component is (b) component / (c) component = 3.5, and [(b) component + (c) component] /
(A) Component = 7.

(2) Heat treatment of pre-prepared catalyst The catalyst solution prepared in the above (1) was put into a stainless steel tube with a stirrer purged with argon gas and immersed in an oil bath whose temperature was adjusted to 90 ° C. Heat treatment was carried out with stirring for minutes. Immediately after the completion of the stirring operation, the stainless steel tube was taken out of the oil bath and cooled with tap water.

(3) Low Polymerization of Ethylene In a 1-liter autoclave equipped with a stirrer, 250 ml of cyclohexane as a polymerization solvent and 12 g of undecane as an internal standard substance were placed under a dry argon gas atmosphere.

Next, 1 ml of the catalyst treated in the above (2) and 20 ml of the solvent cyclohexane were injected into an autoclave in a pot attached with the valve closed in an argon gas atmosphere.

Next, the stirring of the autoclave was started,
The temperature was raised to a reaction temperature of 140 ° C. After the temperature of the autoclave reaches 140 ° C., a dry ethylene supply pipe is connected to the pot, ethylene pressure is applied to the pot, a valve between the autoclave and the valve is opened, and the catalyst liquid in the pot is blown at once. The mixture was charged into the autoclave, ethylene was continuously supplied to the autoclave as it was, and the low polymerization reaction was started at an ethylene pressure of 6.5 MPa.

Every 10 minutes after the start of the reaction, 1
The reaction was carried out for one hour while sampling once. The sample sampled here is immediately injected into a 1N aqueous solution of sodium hydroxide while maintaining the pressure in the autoclave to deactivate the catalyst, and thereby the chemical change of the product due to pressure fluctuation at the time of sampling is measured. Prevented. The collected sample was washed with water, filtered for solid content, and analyzed. Furthermore, light components loss, such as C ₄ fractions such butenes, since unavoidable experimental operation, from C ₈ -C yield of ₂₀ fractions undecane reference internal standard, S
Using the chulz-Flory distribution equation, the production amounts of the C ₄ fraction and the C ₆ fraction were determined.

The main product of this reaction is a linear α-olefin of the C _{4 to} C ₁₈ fraction, and when the purity of the linear α-olefin of the C ₁₈ fraction is increased, other products are obtained. Since the purity of the linear α-olefin of all the fractions can be increased, the purity of the linear α-olefin obtained here is reduced to C ₁₈
It was evaluated by the concentration (Wt%) of 1-octadecene in the linear α-olefin of the fraction.

The impurities which lower the purity of the linear α-olefin of the C ₁₈ cut are branched olefins formed by the further reaction of the α-olefin of the C ₄ -C ₁₆ cut formed by the low polymerization of ethylene, These are vinylidene type olefins and internal olefins, and the amount of these impurities produced, that is, the purity of the linear α-olefin in the C ₁₈ cut varies depending on the amount of α-olefin produced in the C ₄ -C ₁₆ cut.

Therefore, in this embodiment, in order to accurately evaluate the purity of the linear α-olefin of the C ₁₈ fraction,
₄ -C ₁₆ fraction of α- olefin constant production amount of (75
g), the purity of the linear α-olefin of the C ₁₈ fraction was evaluated.

[0044] Further, the amount to C ₂₀ or more heavies product weight and polymer of the obtained oligomer was measured. Table 1 shows the above reaction conditions and evaluation results of the products.

Example 2 The procedure of Example 1 was repeated except that the heat treatment temperature of the pre-prepared catalyst in (2) of Example 1 was changed to 100 ° C. Table 1 shows the reaction conditions and evaluation results of the products.

Example 3 The procedure of Example 1 was repeated except that the temperature of the pretreated catalyst in (2) of Example 1 was changed to 140 ° C. Table 1 shows the reaction conditions and evaluation results of the products.

Example 4 The procedure of Example 1 was repeated except that the heat treatment temperature of the pre-prepared catalyst in (2) of Example 1 was changed to 150 ° C. Table 1 shows the reaction conditions and evaluation results of the products.

Example 5 The procedure of Example 1 was repeated except that the heat treatment temperature of the pre-prepared catalyst in (2) of Example 1 was set at 140 ° C. and the heat treatment time was set at 5 minutes. Table 1 shows the reaction conditions and evaluation results of the products.

Comparative Example 1 The procedure of Example 1 was repeated, except that the preliminarily prepared catalyst was used as it was without performing the heat treatment of the preliminarily prepared catalyst in (2) of Example 1. Table 1 shows the reaction conditions and evaluation results of the products.

Comparative Example 2 The procedure of Example 1 was repeated except that the heat treatment temperature of the pre-prepared catalyst in (2) was changed to 70 ° C. Table 1 shows the reaction conditions and evaluation results of the products.

Comparative Example 3 The procedure of Example 1 was repeated except that the heat treatment temperature of the pre-prepared catalyst in (2) was changed to 80 ° C. Table 1 shows the reaction conditions and evaluation results of the products.

Comparative Example 4 The procedure of Example 1 was repeated except that the heat treatment temperature of the pre-prepared catalyst in (2) was 160 ° C. and the heat treatment time was 5 minutes. Table 1 shows the reaction conditions and evaluation results of the products.

[0053]

[Table 1]

[0054]

[Table 2]

[0055]

According to the present invention, a monomer for polyolefin reforming and a linear α-olefin having high utility as a synthetic lubricating oil, a plasticizer and a surfactant are produced with high purity and high productivity. Can provide a way to

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Claims (5)

[Claims] 1. A method for producing a linear α-olefin by low polymerization of ethylene in the presence of a catalyst, wherein the catalyst comprises (a) a compound represented by the following general formula [1]: [In the formula [1], X independently represents a chlorine atom, a bromine atom or an iodine atom, and A represents an alkoxy group having 1 to 4 carbon atoms. k is 0 or an integer of 1 to 4. A zirconium compound represented by the following general formula [2]: [In the formula [2], R ¹ represents an alkyl group having 1 to 20 carbon atoms, and Q represents a chlorine atom or an iodine atom. m is 1, 1,.
5 or 2. And (c) the following general formula [3]: [In the formula [3], R ² represents an alkyl group having 1 to 20 carbon atoms. Represented by the following formula, the content of each of these catalyst components in molar ratio,
The following equation And the pre-prepared catalyst is
A method for producing a linear α-olefin, comprising using a catalyst obtained by heating at 150 ° C. for 1 to 15 minutes. 2. The linear α according to claim 1, wherein the catalyst is prepared by dissolving each catalyst component in a solvent and adjusting the concentration of the component (a) to 50 to 200 mmol per liter of the solvent. -A process for producing olefins. 3. The preparatory preparation of the catalyst, wherein the order of contact of each catalyst component is prepared by first bringing the component (a) into contact with the component (c) and then bringing the component (b) into contact therewith. Or the method for producing a linear α-olefin according to 2. 4. The process for producing a linear α-olefin according to claim 1, wherein the preliminary preparation of the catalyst is carried out at 60 to 70 ° C. for 0.5 to 3 hours. 5. The linear α-catalyst according to claim 1, wherein the preliminarily prepared catalyst or a catalyst obtained by diluting the catalyst is further heated at 90 to 140 ° C. for 1 to 10 minutes. Olefin production method.