JP2002187902A - PROCESS FOR PREPARATION OF LINEAR alpha-OLEFIN - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for preparing an α-olefin which process is capable of preparing well efficiently a linear α-olefin of high purity while controlling the amount of a byproducted alkyl benzene. SOLUTION: The process for preparing a linear α-olefin by the oligomerization of ethylene using a Ziegler-Natta type catalyst is characterized by preparing the catalyst in the presence of a solvent containing an aromatic solvent and then by carrying out the oligomerization in the presence of an unreactive solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for efficiently producing a high-purity linear α-olefin by oligomerization of ethylene using a Ziegler-Natta type catalyst.

[0002]

2. Description of the Related Art Alpha-olefins are widely used as monomers of olefin polymers or comonomers of various high molecular polymers, and are produced by oligomerizing ethylene in the presence of a Ziegler-Natta type catalyst. . In particular, olefins such as C6 and C8, which are recently used as comonomers of polyolefins, are increasingly required to be highly purified, and the demand for them is increasing year by year. However, the reaction using the Ziegler-Natta type catalyst as described above has a problem that by-products are generated by the reaction of the α-olefin generated in the reaction system, and the purity of the product is reduced. Therefore, it is important to suppress the reaction of α-olefin and give priority to the reaction of ethylene. This not only improves the product quality but also increases the α-olefin concentration in the reactor and lowers the reaction pressure when the purity is the same (same specifications). The significance is very large.

[0003]

In order to improve the purity,
It has been known that when a catalyst is prepared in an aromatic solvent or when an aromatic solvent is used as a reaction solvent, α-olefin purity is improved. However, when an aromatic solvent is used, although the purity is improved, there is a problem that the aromatic solvent reacts with α-olefin and alkylbenzene is produced as a by-product. -There was a problem that the olefin reacts with olefin to produce alkylbenzene as a by-product, which is mixed into the α-olefin of the product. An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a method capable of suppressing the amount of by-product alkylbenzene and efficiently producing a high-purity α-olefin.

[0004]

Means for Solving the Problems The present inventors have made intensive studies in view of the above problems, and have found that an aromatic solvent is used at the time of catalyst preparation, and non-reactive substances such as naphthene solvents are used in the subsequent oligomerization reaction. It has been found that the use of the above solvent increases the purity of the α-olefin and can reduce the amount of by-produced alkylbenzene. The present invention has been completed based on such findings. That is, in the present invention, when producing a linear α-olefin by oligomerization of ethylene using a Ziegler-Natta type catalyst, the catalyst is prepared in a solvent containing an aromatic solvent, and then in a non-reactive solvent. And a method for producing a linear α-olefin, characterized by performing an oligomerization reaction with a linear α-olefin by oligomerization of ethylene using a Ziegler-Natta type catalyst.
In producing an olefin, under a solvent containing an aromatic solvent, and then after preparing a catalyst under a solvent obtained by replacing the solvent containing the aromatic solvent with a non-reactive solvent, or containing an aromatic solvent After preparing a catalyst in a solvent and replacing the solvent containing the aromatic solvent with a non-reactive solvent, a linear α
-To provide a method for producing olefins.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, as described above, a Ziegler-Natta type catalyst is prepared in a solvent containing an aromatic solvent. Here, benzene, toluene, xylene (for example,
o, m, p-xylene), trimethylbenzene (for example, 1,2,4-trimethylbenzene; 1,3,5-trimethylbenzene), tetramethylbenzene, and other alkyl groups such as ethyl group, propyl group, and butyl group And these can be used alone or in combination of two or more. The solvent containing an aromatic solvent used here is an aromatic solvent of 20
It is preferable that the content of 容量 100% by volume be included. When the proportion of the aromatic solvent is out of the above range, the purity of the α-olefin may decrease. The solvent containing the aromatic solvent may contain, for example, a non-reactive solvent used in the oligomerization reaction described below, in addition to the aromatic solvent.

According to the method of the present invention, by preparing a catalyst in the presence of an aromatic solvent, the aromatic solvent coordinates to the catalyst, thereby suppressing the reinsertion addition reaction of the α-olefin. As a result, it is considered that the purity of the α-olefin is improved and by-products of by-products are suppressed. In the present invention, it is also preferable in the present invention that during or after preparation of the catalyst, the solvent containing an aromatic solvent is replaced with a non-reactive solvent, and then the oligomerization reaction is performed under a non-reactive solvent. It is an aspect. That is, after preparing a catalyst in a solvent containing an aromatic solvent and then replacing the solvent containing the aromatic solvent with a non-reactive solvent, the oligomerization reaction is performed in a non-reactive solvent. Or a method of preparing a catalyst in a solvent containing an aromatic solvent, replacing the solvent containing the aromatic solvent with a non-reactive solvent, and then performing an oligomerization reaction in a non-reactive solvent. Can be

For the replacement of the solvent, for example, a solvent containing an aromatic solvent is added to the transition metal component, and the mixture is heated at a temperature of, for example, 70 ° C. or more, cooled, the solid is precipitated, and the liquid phase is decanted. It can be carried out by repeating the operation of removing and adding the same amount of non-reactive solvent as the amount removed to replace the solvent. After replacing the solvent containing the aromatic solvent with the non-reactive solvent in this way, another catalyst component can be added to prepare a catalyst solution. Of course, after adding a solvent containing an aromatic solvent to the transition metal component and further adding another catalyst component, the solvent can be replaced with a non-reactive solvent.

In the present invention, the order of blending each component of the Ziegler-Natta type catalyst and the solvent is not particularly limited. However, after adding a solvent containing an aromatic solvent to the transition metal component of the catalyst component, other components are added. It is preferred to add a catalyst component. For example, ZrCl ₄ - ethyl aluminum sesquichloride (hereinafter, sometimes abbreviated as EASC) - triethylaluminum when preparing (hereinafter sometimes abbreviated as TEA) catalyst is first aromatic solvent ZrCl ₄ It is preferable to add a solvent containing EASC, add TEA, and then add EASC. After blending all the components, for example, by heating at a temperature of 40 ° C. or higher, preferably 50 to 80 ° C. for 30 minutes or longer, a more highly active catalyst can be obtained. The mixing ratio of the catalyst component and the aromatic solvent in the above method is 50 to 100 as the concentration of ZrCl _4.
Mmol / liter solvent.

In the method of the present invention, a catalyst is prepared in a solvent as described above, and then an oligomerization reaction is performed in a non-reactive solvent. Non-reactive solvents include naphthenic compounds such as cyclohexane and ethylcyclohexane,
Examples include paraffinic compounds such as pentane, heptane, and octane, and halides thereof (for example, chlorides). In particular, naphthenic compounds can be preferably used. The oligomerization of ethylene can be performed efficiently by bringing the catalyst solution prepared as described above and ethylene into contact with each other at a predetermined reaction temperature and a predetermined reaction pressure in the presence of a non-reactive solvent.

For example, the polymerization reaction of ethylene is usually 1
30-70 kg / cm ² · G at a temperature of 00-130 ° C
(2.94-6.86 MPa). Also,
The reaction time depends on the temperature and pressure, but usually,
About 10 to 60 minutes is enough. In addition, all operations from the preparation of the catalyst to the end of the polymerization reaction are preferably performed with exclusion of air and moisture, and are preferably performed in an atmosphere of an inert gas such as nitrogen or argon. In the production method of the present invention, ethylene is used as a raw material,
The obtained linear α-olefin has 4 or more carbon atoms, particularly 4 carbon atoms.
To 18 low-polymerized α-olefins,
Olefin oligomers are formed as a mixture thereof.
In the present invention, the reaction product solution obtained by polymerizing ethylene can be subjected to, if necessary, recovery of unreacted α-olefin, deactivation of the catalyst, demineralization treatment and the like.

[0011]

Next, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples. Example 1 (1) Preparation of Catalyst Under an argon atmosphere, 25 mmol of anhydrous zirconium tetrachloride and 250 ml of dry toluene were introduced into a 500-ml flask equipped with a stirrer and stirred for 10 minutes.
To this, 38.9 mmol of triethylaluminum (TEA) was added, and after stirring for about 10 minutes, 136.1 mmol of ethylaluminum sesquichloride (EASC) [molar ratio of (EASC + TEA) / ZrCl ₄ = 7, E
ASC / TEA molar ratio = 3.5)]
To form a complex with stirring for 1 hour. The catalyst solution is
The color changed to reddish brown due to complex formation. (2) Oligomerization of ethylene 250 ml of cyclohexane dried under a dry argon atmosphere in a 1 liter autoclave with a stirrer.
And a predetermined amount of undecane as an internal standard substance, and 13
The temperature was raised to 0 ° C. When the temperature reached 130 ° C., the above prepared catalyst previously introduced into the pot (ZrCl ₄ : 0.08 mmol, EASC: 0.426 mmol, TEA: 0.12)
(4 mmol) together with the raw material ethylene, and the reaction pressure was increased to 6.5 MPa. Then 10
Samples were withdrawn every minute and reacted for 1 hour. During this time, ethylene was continuously charged to keep the reaction pressure constant. 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 deactivated at a stretch with a high pressure from a reactor in a 1N aqueous sodium hydroxide solution. This sampling was performed every 10 minutes, and a total of six samples were collected up to 60 minutes. These samples were washed with water, the solid content was filtered off, and subjected to analysis.

Since light components such as C4 are inevitably loss to some extent in the experimental operation, Schulz is calculated from the amount of the undecane-based C8-C30 fraction of the internal standard.
-The C4 and C6 production amounts were determined using the Flory distribution, and the yield was determined. Further, the decrease in the purity of the α-olefin is caused by the reaction of the α-olefin produced in the reaction and by-products. For example, the purity of C18 [C18
1-octadecene concentration in the fraction (% by weight)] is related to the yield of α-olefins from C4 to C16 produced in the reaction.
18 Purity decreases. Thus, α-olefin purity,
For example, the C18 purity relates to the yield of α-olefins from C4 to C16 when the reaction conditions (temperature, pressure) are the same. No accurate purity improvement effect can be seen. Therefore, Table 1 shows that when the relative olefin concentration [C4 to C16α-olefin / ethylene (molar ratio)] in the reaction field affecting the C18 purity is 0.002,
Comparison was made with 18α-olefin purity.

Example 2 The procedure of Example 1 was repeated, except that benzene was used instead of toluene as the solvent during catalyst preparation, and the C18α-olefin purity and the amount of alkylbenzene produced were measured. The results are shown in Table 1. Example 3 The procedure of Example 1 was repeated, except that mesitylene was used instead of toluene as the solvent during catalyst preparation, and the C18α-olefin purity and the amount of alkylbenzene produced were measured.
The results are shown in Table 1.

Example 4 25 mmol of anhydrous zirconium tetrachloride and 250 ml of dry toluene were introduced into a flask equipped with a stirrer having an inner volume of 500 ml under an argon atmosphere, followed by heating and stirring at 70 ° C. for 30 minutes. Thereafter, the mixture was cooled to room temperature and the solid of the slurry catalyst was settled. After that, extract the liquid phase with a syringe,
Dry cyclohexane corresponding to the amount withdrawn was added and stirred. This solvent replacement was performed three times. Thus,
After replacing most of the solvent with cyclohexane, 38.9 mmol of triethylaluminum (TEA) was added, and after stirring for about 10 minutes, 136.1 mmol of ethylaluminum sesquichloride (EASC) [(EAS)
C + TEA) / ZrCl ₄ molar ratio = 7, EASC / T
EA molar ratio = 3.5], and a complex was formed with stirring at 70 ° C. for 1 hour. For the product, C18α
-Olefin purity and alkylbenzene production were measured. The results are shown in Table 1.

Example 5 The same operation as in Example 1 was carried out except that a mixed solvent of benzene and cyclohexane (benzene: cyclohexane = 50: 50) was used instead of toluene as a solvent for preparing the catalyst. The C18α-olefin purity and the amount of alkylbenzene produced were measured. The results are shown in Table 1. Example 6 The same operation as in Example 1 was carried out except that a mixed solvent of benzene and cyclohexane (benzene: cyclohexane = 30: 70) was used instead of toluene as a solvent for preparing the catalyst, and the product was a C18α-olefin. The purity and the amount of alkylbenzene produced were measured. The results are shown in Table 1.

Comparative Example 1 The procedure of Example 1 was repeated, except that cyclohexane was used instead of toluene as the solvent during catalyst preparation, and the C18α-olefin purity and the amount of alkylbenzene produced were measured for the product. The results are shown in Table 1. Comparative Example 2 The procedure of Example 1 was repeated, except that toluene was used instead of cyclohexane as the solvent for the polymerization reaction, and the C18α-olefin purity and the amount of alkylbenzene produced for the product were measured. The results are shown in Table 1. Comparative Example 3 The same operation as in Example 1 was carried out except that benzene was used instead of toluene as the solvent at the time of preparing the catalyst, and benzene was used instead of cyclohexane as the solvent for the polymerization reaction. The amount of alkylbenzene produced was measured. The results are shown in Table 1. The first
In the table, Tol represents toluene, Bz represents benzene, Mes represents mesitylene, and Cy represents cyclohexane.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

According to the present invention, the amount of alkylbenzene as a by-product can be suppressed, and a highly pure linear α-olefin can be efficiently produced by a simple operation.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C08F 4/642 C08F 4/642 F-term (Reference) 4H006 AA02 AC29 BA09 BA10 BA39 BA44 BB11 BB12 4H039 CA19 CL19 4J011 HA03 HB22 4J028 AA01A AB00A AC24A BA00A BA02B BB00A BB02B BC15B BC19B EB02 FA02 GA02 4J128 AA01 AB00 AC24 BA00A BA02B BB00A BB02B BC15B BC19B EB02 FA02 GA02

Claims (5)

[Claims] In producing a linear α-olefin by oligomerization of ethylene using a Ziegler-Natta type catalyst, the catalyst is prepared in a solvent containing an aromatic solvent and then in a non-reactive solvent. A method for producing a linear α-olefin, comprising performing an oligomerization reaction. 2. The linear α-olefin according to claim 1, wherein the Ziegler-Natta catalyst is prepared by heating at a temperature of 40 ° C. or more for 30 minutes or more in a solvent containing an aromatic solvent. Manufacturing method. 3. A process for producing a linear α-olefin by oligomerization of ethylene using a Ziegler-Natta type catalyst, in the presence of a solvent containing an aromatic solvent and then using a non-reactive solvent containing the aromatic solvent. After preparing the catalyst in a solvent substituted with the solvent of, or after preparing the catalyst in a solvent containing an aromatic solvent and replacing the solvent containing the aromatic solvent with a non-reactive solvent, A method for producing a linear α-olefin in which an oligomerization reaction is carried out in a neutral solvent. 4. The method for producing a linear α-olefin according to claim 1, wherein the non-reactive solvent is a naphthene compound, a paraffin compound or a halide thereof. 5. The method according to claim 1, wherein the Ziegler-Natta type catalyst is obtained by adding a solvent containing an aromatic solvent to a transition metal component and then adding another catalyst component. A method for producing a linear α-olefin.