JP2946753B2 - Purification method of ethylene-α-olefin copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying an ethylene-.alpha.-olefin copolymer. More specifically, the present invention employs a catalyst system comprising a vanadium compound and an organoaluminum compound or a catalyst system comprising a vanadium compound, an organoaluminum compound and a halogenated ester compound in the presence of a hydrocarbon solvent, wherein ethylene and carbon atoms are 3 or more. Α-olefin, or ethylene and 3 carbon atoms
The present invention relates to a method for removing a catalyst component and the like from an ethylene-α-olefin-based copolymer obtained by copolymerizing the above α-olefin and a non-conjugated diene compound.

[0002]

2. Description of the Related Art In the presence of a hydrocarbon solvent, ethylene-α is prepared by using a catalyst system comprising a vanadium compound and an organoaluminum compound or a catalyst system comprising a vanadium compound, an organoaluminum compound and a halogenated ester compound.
-In the case of producing an olefin-based copolymer, if the used catalyst components and the like remain and mix in the final product of the copolymer, problems such as discoloration of the copolymer, deterioration of weather resistance, deterioration of heat resistance, etc. Occurs. Therefore, it is necessary to sufficiently remove the remaining catalyst components and the like from the copolymer obtained by the polymerization reaction.
Conventionally, ethylene produced using a vanadium-based catalyst
As a method of removing the catalyst component from the α-olefin-based copolymer, a large amount of water is added to the polymer solution, mixed with a mixer or the like, and the catalyst is extracted into an aqueous phase, and then the aqueous and organic phases are separated. A method for obtaining a polymer having reduced catalyst components from an organic phase, or a slurry obtained by a copolymerization reaction in a solvent that does not dissolve the polymer, by adding water or alcohol to the catalyst in the copolymer. Methods for reducing residues are known (for example, Koji Saeki, "Polymer Manufacturing Process", Industrial Research Committee, 1971). However, these methods have several disadvantages. For example, in a method of treating with a large amount of water, it is considered that the catalyst component solubilized in water is extracted into water by contact of the catalyst with water, but when it is expected to more completely remove the catalyst component, etc. In addition, it is necessary to sufficiently mix the polymer solution and water. For this purpose, a large and powerful mixing mixer must be used and the number of rotations must be high, which requires a large amount of equipment and power costs, and is not industrially advantageous. Further, in the method using alcohol or the like, it is necessary to purify and reuse the used alcohol, which complicates the process and increases energy consumption, which is not advantageous. As another method, JP-A-63-275605 discloses a copolymer obtained using a titanium-based catalyst,
A method of washing with water containing an alkaline compound is disclosed.Japanese Patent Publication No. 43-6471 further discloses that a copolymer obtained using a vanadium-based catalyst is oxidized, and then the alkaline compound is contained. A method of treating with water is disclosed. By the way, in recent years, ethylene-α-olefin-based rubbery copolymers have been widely used for automobile parts, packaging materials and the like by being mixed with a resin such as polypropylene. Demands for coalescence, such as weather resistance and non-coloring properties, have become more severe. In order to satisfy the demand, it is strongly required to further reduce the catalyst component remaining in the rubbery copolymer. For example, a vanadium compound is 1 ppm in terms of V ₂ O _5.
It has become desirable to: In addition to the metal catalyst component, there is a problem that the halogenated ester compound used as an activator of the polymerization reaction remains in the copolymer. When the halogenated ester compound remains in the copolymer, the quality of the copolymer deteriorates due to halogen,
That is, there is a problem that corrosion of the processing machine and coloring of the copolymer occur, making it impossible to use the containers for foods and pharmaceuticals and packaging materials. In light of such demands, the prior art described in each of the above publications is still unsatisfactory.

[0003]

In view of the above situation, the present inventors have developed a catalyst system comprising a vanadium compound and an organoaluminum compound, or a vanadium compound, an organoaluminum compound and a halogenated ester in the presence of a hydrocarbon solvent. An ethylene-α-olefin copolymer obtained by polymerizing ethylene and an α-olefin having 3 or more carbon atoms or ethylene and an α-olefin having 3 or more carbon atoms and a non-conjugated diene compound using a catalyst system comprising a compound. In the case of purifying the coalesced substance, the present inventors have assiduously studied for the purpose of providing a method capable of removing a catalyst component or the like to a level that cannot be achieved by the conventional method, and have reached the present invention. .

[0004]

That is, the present invention provides a catalyst system comprising a vanadium compound and an organoaluminum compound or a catalyst system comprising a vanadium compound, an organoaluminum compound and a halogenated ester compound in the presence of a hydrocarbon solvent. A method for purifying an ethylene-α-olefin-based copolymer obtained by polymerizing ethylene and an α-olefin having 3 or more carbon atoms, or an ethylene-α-olefin having 3 or more carbon atoms and a non-conjugated diene compound, The polymerization reaction mixture obtained by the polymerization reaction, the following process comprising the step of performing an oxidizing agent treatment in the co-presence of an aqueous alkaline solution in an amount such that the pH of the aqueous phase after the oxidation treatment is 10.0 or more. The present invention relates to a method for purifying an α-olefin copolymer.

The details will be described below. In the present invention, a catalyst system comprising a vanadium compound and an organoaluminum compound, which is subjected to purification in the presence of a hydrocarbon solvent,
Alternatively, using a catalyst system comprising a vanadium compound, an organoaluminum compound and a halogenated ester compound, a polymerization reaction of ethylene with an α-olefin having 3 or more carbon atoms or ethylene with an α-olefin having 3 or more carbon atoms and a non-conjugated diene compound. It is a polymerization reaction mixture containing an ethylene-α-olefin copolymer obtained by the above.

[0006] As the hydrocarbon solvent, either a solvent soluble in the copolymer or a solvent that does not dissolve the copolymer can be used. For example, aromatic compounds such as benzene and toluene,
Pentane, hexane, aliphatic hydrocarbon compounds such as heptane, cyclopentane, methylcyclopentane, alicyclic hydrocarbon compounds such as cyclohexane, liquefied propylene, liquefied 1-butene, α-olefins such as 4-methylpentene-1, And mixtures thereof are preferably used.

As the vanadium compound, for example, VC
l ₃ , VCl ₄ , VOCl ₃ , VO (OR) _3-m Cl _m (R is carbon number 1 to 1
0 linear or branched alkyl group, cycloalkyl group or aryl group, 3 ≧ m ≧ 0) and the like, and VO (OCH ₃ )
_{Cl 2, VO (OCH 3)} 2 Cl, VO (OH 3) 3, VO (OC 2 H 5) Cl 2, VO (OC 2
_{H 5) 2 Cl, VO (} OC 2 H 5) 3, VO (OC 3 H 7) Cl 2, VO (OC 3 H 7) 2 Cl, VO
(OC ₃ H ₇ ) ₃ , VO (OisoC ₃ H ₇ ) Cl ₂ , VO (OisoC ₃ H ₇ ) ₂ Cl, VO (O
isoC ₃ H ₇ ) ₃ , V (OCH ₃ ) ₃ , V (OCH ₂ COOCH ₃ ) _{3 and the} like.

As the organoaluminum compound, for example, AlR'nCl _3-n or AlR'n (OR ') _{3 -n} (R' has 1 carbon atom)
To 8 linear or branched alkyl groups, 3 ≧ n ≧ 0), (C ₂ H ₅ ) ₂ AlCl, (C ₄ H ₉ ) ₂ AlCl, (C ₆ H ₁₃ ) ₂ AlCl, (C ₂ H
₅ ) _1.5 AlCl _1.5 , (C ₄ H ₉ ) _1.5 Al Cl _1.5 , (C ₆ H ₁₃ ) _1.5 AlCl
_1.5 , C ₂ H ₅ AlCl ₂ , C ₄ H ₉ AlCl ₂ , C ₆ H ₁₃ AlCl _{2 and the} like.

In the present invention, in addition to these catalyst components, an activator of the polymerization reaction and a regulator of the composition distribution and molecular weight can be used. For example, using an activator for the polymerization reaction, a halogenated ester compound as a narrowing agent for the composition distribution, hydrogen as a molecular weight regulator, etc.
It is preferable for controlling the structure of the copolymer in industrial practice. In this case, as the halogenated ester compound, for example, a compound represented by the following general formula (Where R "is an organic group partially or entirely halogen-substituted with 1 to 20 carbon atoms, and R"'is a hydrocarbon group having 1 to 20 carbon atoms), and preferably R " Compounds in which all of the substituents are chloro-substituted, or compounds having a phenyl group and a chloro-substituted alkyl group, more preferably perchlorcrotonate, perchlor-3-butenylate or phenyldichloroacetate. Specifically, ethyl dichloroacetate, methyl trichloroacetate, ethyl trichloroacetate,
Methyl dichlorophenyl acetate, ethyl dichlorophenyl acetate, methyl perchlor crotonate, ethyl perchlor crotonate, propyl perchlor chlorotonate, isopropyl perchlor crotonate, butyl perchlor crotonate, butyl perchlor crotonate, cyclopropyl perchlor crotonate, phenyl Perchlorlorcrotonate, methyl perchlor-3-butenylate, ethyl perchlor-3-butenylate, propyl perchlor-3-butenylate,
Perchlor-3-butyl butenylate and the like can be exemplified.

As the α-olefin having 3 or more carbon atoms,
For example, propylene, 1-butene, 1-pentene, 1
-Hexene, 4-methylpentene-1, 1-octene,
1-decene and the like are exemplified. Examples of the non-conjugated diene compound include dicyclopentadiene, tricyclopentadiene, 5-methyl-2,5-norbornadiene,
-Methylene-2-norbornene, 5-ethylidene-2-
Norbornene, 5-isopropylidene-2-norbornene, 5-isopropenyl-2-norbornene, 5-
(1′-butenyl) -2-norbornene, 5- (2′-
Butenyl) -2-norbornene, 1,4-hexadiene, 1,6-octadiene, 6-methyl-1,5-heptadiene and the like. There are no restrictions on the conditions of the polymerization reaction other than the above. Thus, a polymerization reaction mixture which is subjected to the purification of the present invention is obtained.

The purification method of the present invention comprises a step of subjecting the above polymerization reaction mixture to an oxidizing treatment in the presence of an alkaline aqueous solution in an amount such that the pH of the aqueous phase after the following oxidizing treatment becomes 10.0 or more. This is a method for purifying an ethylene-α-olefin copolymer. Further, as a more specific and preferable method, a method comprising the following first step and second step can be mentioned. First step: The polymerization reaction mixture contains an oxidizing agent in a stoichiometric amount or more necessary to oxidize vanadium present in the mixture to pentavalent, and the aqueous phase separated in the following second step A step of treating with an aqueous solution containing an amount of an alkaline compound at which the pH becomes 10.0 or more. Second step:
Separating the mixture obtained in the first step into an aqueous phase and an organic phase, and washing the obtained organic phase with neutral water. Furthermore, a method comprising the following first to third steps can be mentioned. First step: The polymerization reaction mixture obtained by the above polymerization reaction is adjusted to pH 10.0 of the aqueous phase formed as a result of the second step below.
A step of treating with an alkaline aqueous solution containing the above amount of an alkaline compound. Second step: 1/5 parts by volume of the mixture obtained in the first step, water containing at least a stoichiometric amount of oxidizing agent necessary for oxidizing vanadium present in the mixture to pentavalent From 10 to 10 parts by volume.
Third step: a step of separating the mixture obtained in the second step into an aqueous phase and an organic phase, and washing the obtained organic phase with neutral water.

Examples of the alkaline compound used in the present invention include lithium hydroxide, sodium hydroxide, potassium hydroxide, concentrated ammonia, ammonium hydroxide and the like. Among them, lithium hydroxide, potassium hydroxide, water Sodium oxide is particularly preferred. The required amount of the alkaline compound to be used is an amount sufficient to adjust the pH of the aqueous phase separated from the organic phase after the oxidation treatment to 10.0 or more, preferably 11 or more. Insufficient alkaline compounds result in insufficient removal of catalyst components and the like. As a preferred embodiment of the method of adding the alkaline aqueous solution, a method of adjusting the pH of the alkaline aqueous solution to be added to 12 or more, preferably 13 or more, and using 1/1000 to 10 parts by volume with respect to 1 part by volume of the polymerization reaction mixture is mentioned. .

The oxidizing agents used include, for example, sodium nitrite, potassium nitrite, hydrogen peroxide,
Examples include alkali nitrates such as hydroxylamine hydrochloride, persulfates, peroxides, hypochlorite, oxygen, ozone, and air. Among them, the use of air or oxygen as the oxidizing agent is simple in handling and there is no concern that the oxidizing agent remains in the copolymer.
Particularly preferred. The amount of oxidizing agent used is at least the stoichiometric amount necessary to oxidize all vanadium present in the polymerization reaction mixture to pentavalent. If the amount of oxidant is insufficient,
Removal of the catalyst component and the like becomes incomplete, and the effect of the present invention is not exhibited. Furthermore, the valence of all vanadium can be increased to a pentavalent oxidation state by using an oxidizing agent twice or more the above stoichiometric amount. Since pentavalent vanadium is colorless and transparent, it is preferable in that the coloring of the copolymer as the final product can be completely prevented. However, when an oxidizing agent other than oxygen is used, if the oxidizing agent is added in a large excess, the oxidizing agent remains in the final copolymer, which is not preferable.
It is desirable to use 10 times or less of the above stoichiometric amount. When oxygen is used as an oxidizing agent, there is no need to worry about remaining in the copolymer even if it is made to act excessively. However, when applied to a continuous polymerization process (including a solvent circulation process), It is not preferable because it causes oxygen accumulation, oxidative degradation of the copolymer, etc., and is therefore preferably 50 times or less the stoichiometric amount. However, this does not apply when the post-process has a deoxidizing agent process.

The amount of water used in the treatment is an amount sufficient to effectively extract water mainly from the ash generated from the catalyst component, and an amount capable of separating the organic phase and the aqueous phase. It is necessary to specifically add 1 to 1 part by volume of the polymerization mixture.
/ 5 to 10 parts by volume is preferable, and 1/4 to 5 parts by volume is more preferable. It is desirable that the water used here has as little iron content as possible. The presence of iron in water induces coloration of the target copolymer. The preferred iron concentration is 0.1 ppm or less.

The method of treating the polymerization reaction mixture with an alkaline aqueous solution and an alkaline aqueous solution containing an oxidizing agent may be carried out by any method as long as the catalyst components and the aqueous solution are efficiently contacted and the catalyst components and the like are sufficiently extracted into the aqueous phase. Good.
Specifically, a method using a line mixer and the like can be mentioned. A specific method of the step of separating into an aqueous phase and an organic phase is not particularly limited, and examples thereof include a method using a so-called stationary separation drum. The step of treating the polymerization reaction mixture with these alkaline aqueous solution and the oxidizing agent-containing alkaline aqueous solution and the step of separating the aqueous and organic phases,
Normal temperature 20 ~ 160 ℃, preferably 50 ~ 100 ℃, pressure 0 ~
It can be carried out under the conditions of ²⁰ kg / cm ² G, preferably ^{2 to} 10 kg / cm ² G. In carrying out the process, it is preferable to perform water washing a plurality of times after passing through the above-mentioned treatment step of the polymerization reaction mixture with the alkaline aqueous solution and the alkaline aqueous solution containing the oxidizing agent and the step of separating the aqueous and organic phases. The organic phase containing the target copolymer thus obtained is subjected to a usual post-treatment step. That is, for example, the target ethylene-α-olefin-based copolymer can be obtained by distilling off the hydrocarbon solvent by heating and evaporating and drying.

Next, the operation of the present invention will be described. Although the features of the present invention have already been described in the relevant places, the most important feature in the constitution of the present invention is that the oxidation treatment is performed in the presence of an alkaline aqueous solution. As to why the effect of the present invention can be expressed for the first time by such a characteristic configuration, the present inventors have conducted intensive studies,
The following conclusions were reached. When the polymerization reaction mixture is treated with an aqueous alkaline solution, a water-insoluble low-valent vanadium compound remains in the organic phase. Then, when vanadium is oxidized to a pentavalent oxidation state by an oxidizing agent, the hydroxide of pentavalent vanadium moves to the aqueous phase because of its good solubility in water and is removed from the organic phase. On the other hand, when the oxidation treatment is performed in a neutral or acidic state, a vanadium oxide is generated. This compound is inferior in solubility in water even afterwards under alkaline conditions, and is therefore difficult to move to and remove from the aqueous phase.
Therefore, the vanadium compound will remain in the target copolymer. The organoaluminum compound and the halogenated ester as a polymerization activator are decomposed and extracted into an aqueous phase by treatment with an alkaline aqueous solution. In addition, the oxidation treatment does not hinder the extraction and has an effect of promoting the extraction of vanadium into the aqueous phase.

[0017]

EXAMPLES The present invention will be described below with reference to examples.

Example 1 Vanadium oxytrichloride, ethylaluminum sesquichloride, and BPCC (n-butyl perchlorchlortonate, manufactured by Malincklot Co., USA, according to the catalog)
Using a catalyst consisting of
In this manner, ethylene and propylene were copolymerized to prepare a hexane solution containing an ethylene-propylene copolymer. This ethylene / propylene copolymer (ethylene content 73 wt%) in hexane homogeneous solution (copolymer approximately 8 wt%) was 47 ppm as V ₂ O _{5 in} terms of copolymer and A
It contained 560 ppm of l ₂ O ₃ and 700 ppm of Cl. In 2000 ml of the hexane solution of the copolymer, 10 g of sodium hydroxide was dissolved in 200 ml of pure water (a saturated solution of air at atmospheric pressure, iron content 0.1 ppm or less).
l / l, pH 14 or more) at 60 ° C under nitrogen atmosphere.
The mixture was mixed and stirred with a mixer at Kg / cm ² G for 5 minutes (12000 rotations / minute). After stirring, an additional 500 ml of pure water (air in which air was saturated and dissolved at atmospheric pressure) was added, and the mixture was further mixed and stirred for 5 minutes (12000 rpm). After standing and separating for about 10 minutes, the pH of the aqueous phase was measured to be 13.4. Add 500 ml of neutral pure water to the separated oil phase, mix and stir for 5 minutes (12000 rpm) with a mixer, wash, and then distill hexane from the oil phase by heating and distilling off the copolymer. To
The ash content was measured by X-ray fluorescence analysis. Further, the coloring state of the obtained copolymer was visually evaluated. The results are shown in Table 1.

Examples 2 and 3 The procedure was essentially the same as in Example 1, except that the concentration of the aqueous alkali solution and the amount of the aqueous solution were changed. Table 1 shows the conditions and results.

Comparative Example 1 The procedure was carried out in essentially the same manner as in Example 1, except that no alkali was used. The results are shown in Table 1.

Example 4 Ethylene 913 g / Hr, propylene 1630 were placed in a 50 L polymerization tank.
g / Hr and hexane 4.08 L / Hr, vanadium oxytrichloride 0.
32mmol / Hr, ethyl aluminum sesquichloride 6.8m
mol / Hr, and a continuum of 0.28 g / Hr manufactured by Malin Clot Co. of America as a polymerization activator, and further, while supplying 7.2 L / Hr of hydrogen as a molecular weight regulator, a reaction temperature of 50 ° C.
The polymerization reaction was carried out at a pressure of 13 kg / cm ² G. The reaction mixture in the polymerization tank was continuously extracted while controlling the liquid volume in the polymerization tank to 25 L. The withdrawn reaction mixture was led to a flash drum, where the pressure was 0.8 kg / cm ²
G. Flush at 60 ° C. to remove monomer gas. Note that heated hexane was added to maintain the temperature of the flash solution. An aqueous solution of sodium hydroxide (concentration: 0.16 mol / L, pH 13.2) was added at a rate of 200 ml / Hr to 11.6 kg / Hr (about 18 L / Hr) of the polymerization reaction mixture thus obtained, and mixed with a mixer. did. Next, water saturated with air (20 ° C., 1 kg
/ cm ² G saturated with air, iron content 0.1ppm or less) 5L / H
After adding r and mixing with a mixer, an organic phase and an aqueous phase were separated by a stationary separation drum. The obtained organic phase was washed with water to obtain a final organic phase. Hexane was distilled off from the final organic phase by a flash operation, and after drying, an ethylene-propylene copolymer was obtained. The obtained copolymer was analyzed for Cl, Al ₂ O ₃ , and V ₂ O ₅ contents (X-ray fluorescence method), and the coloring state was visually evaluated. The results are shown in Table 2.

Example 5 A reaction was carried out in substantially the same manner as in Example 1 except that no polymerization activator was used. The results are shown in Table 2.

Example 6 The same procedure as in Example 1 was carried out except that 1-butene was used instead of propylene as the α-olefin and degassed alkaline water was used. The results are shown in Table 2.

Comparative Examples 2 and 3 Except that the air-saturated water used in Examples 4 and 5 was replaced with deaerated pure water containing no air,
The procedure was essentially the same as in Example 1 or 2. The results are shown in Table 2.

Table 1 Example Comparative Example 1 2 3 1 Alkaline aqueous solution ⁽¹⁾ Alkaline compound NaOH NaOH NaOH None Concentration mol / l 1.25 2.50 2.500 pH>14>14> 147 Aqueous solution volume ml 200 10 20 Pure water ⁽²⁾ ml 500 500 500 500 Feed 0 ₂ / equivalent 0 ₂ ⁽³⁾ 7 5 5 5 Water phase pH after oil / water separation 13.4 12.4 11.4 4.0 Evaluation of copolymer after purification V ₂ O ₅ ppm <1 <1 <1 15 Al ₂ O ₃ ppm 64 25 77 Cl ppm 20 24 28 47 Color White White White Light yellow (1), (2): Use air-saturated water (3): “Equivalent 0 ₂ ”: 5 vanadium 0 ₂ weight aqueous alkali solution treatment-oil-water separation required for oxidation to the valence, the 60
C., 0 kg / cm ² G.

Table 2 Example Comparative Example 4 5 6 2 3 Amount supplied during polymerization Polymerization solvent 1 / Hr 4.1 7.3 4.9 3.4 5.2 Ethylene g / Hr 910 590 622 660 430 α-Olefin (a) g / Hr 1630 2220 545 1120 1610 V compound (b) mmol / Hr 0.32 5.7 0.14 0.23 4.10 Organic Al compound (C) mmol / Hr 6.8 22.2 4.0 4.8 16.1 Polymerization activator (d) g / Hr 0.28 None 0.13 0.20 None Polymerization temperature ℃ 50 40 60 50 40 Alkaline aqueous solution ⁽¹⁾ Alkaline compound NaOH NaOH NaOH NaOH NaOH Concentration mol / l 0.16 0.41 0.30 0.16 0.50 pH 13.2 13.6 13.5 13.2 13.7 Aqueous solution volume l / Hr 0.2 0.2 0.2 0.2 0.2 Added pure water ⁽²⁾ l / Hr 55 5 5 5 Feed 0 ₂ / equivalent 0 ₂ ⁽³⁾ 17 235 0-0 0 Water phase pH after water separation 10.4 10.4 11.0 10.6 10.8 Evaluation of copolymer after purification V ₂ O ₅ ppm <1 2 <16 35 Al ₂ O ₃ ppm 9 11 3 22 15 Cl ppm 9 <1 3 10 <1 color white white white light gray grey-green (a): butene-1 in Example 6, propylene in others : Vanadium oxytrichloride (c): Ethyl aluminum sesquichloride (d): BPCC (1): Examples 4, 5, using air-saturated water Example 6, Comparative Examples 2, 3, using deaerated water (2): Examples 4 to 6 use air-saturated water Comparative examples 2 and 3 use deaerated water (3): "Equivalent 0 ₂ ": 0 necessary for oxidizing vanadium to pentavalent ₂ volume alkaline aqueous solution treatment-oil-water separation is 70
C., 3 kg / cm ² G.

[0027]

As described above, according to the present invention, a catalyst system comprising a vanadium compound and an organic aluminum compound or a catalyst system comprising a vanadium compound, an organic aluminum compound and a halogenated ester compound is used in the presence of a hydrocarbon solvent. Purification of ethylene-α-olefin copolymer obtained by polymerizing ethylene and α-olefin having 3 or more carbon atoms, or ethylene and α-olefin having 3 or more carbon atoms and diene having a non-conjugated double bond It has been possible to provide a method capable of removing a catalyst component, a halogenated ester and the like to a level which cannot be achieved by the conventional method.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Katsunari Inagaki 5-1, Anesaki Beach, Ichihara City, Chiba Prefecture Within Sumitomo Chemical Co., Ltd. (56) References JP-A-53-22583 (JP, A) JP-A-63- 275605 (JP, A) JP 43-6471 (JP, B1) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08F ⁶ /00-6/28

Claims (5)

(57) [Claims] 1. A catalyst system comprising a vanadium compound and an organoaluminum compound in the presence of a hydrocarbon solvent, wherein ethylene and an α-olefin having 3 or more carbon atoms or ethylene and an α-olefin having 3 or more carbon atoms are not conjugated. A method for purifying an ethylene-α-olefin copolymer obtained by polymerizing a diene compound with a diene compound, wherein a polymerization reaction mixture obtained by the polymerization reaction is treated with p
Ethylene-α characterized by comprising a step of performing an oxidation treatment in the co-presence of an alkaline aqueous solution having an amount of H of 10.0 or more.
-A method for purifying an olefin-based copolymer. 2. The purification method according to claim 1, comprising the following first step and second step. First step: the above-mentioned polymerization reaction mixture is treated with 5% of vanadium present in the mixture.
Treating with an aqueous solution containing an oxidizing agent in a stoichiometric amount or more necessary to oxidize to a valence, and containing an alkaline compound in an amount such that the pH of the aqueous phase separated in the second step below becomes 10.0 or more. . Second step: a step of separating the mixture obtained in the first step into an aqueous phase and an organic phase, and washing the obtained organic phase with neutral water. 3. The purification method according to claim 1, comprising the following first step, second step and third step. First step: a step of treating the polymerization reaction mixture obtained by the polymerization reaction with an alkaline aqueous solution containing an alkaline compound in an amount such that the pH of an aqueous phase formed as a result of the following second step becomes 10.0 or more. Second step: 1 part by volume of the mixture obtained in the first step, from 1/5 of water containing a stoichiometric amount or more of an oxidizing agent necessary for oxidizing vanadium present in the mixture to pentavalent Process with 10 volumes. Third step: a step of separating the mixture obtained in the second step into an aqueous phase and an organic phase, and washing the obtained organic phase with neutral water. 4. The method according to claim 1, wherein the oxidizing agent is oxygen. 5. The method according to claim 1, wherein the catalyst system is a catalyst system comprising a vanadium compound, an organoaluminum compound and a halogenated ester compound.