JPH0813853B2 - Method for producing styrene polymer and its catalyst - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a styrene-based polymer and a catalyst used in the method, and more specifically, the stereochemical structure of the polymer chain mainly has a syndiotactic structure. The present invention relates to a method for efficiently producing a styrene polymer and a catalyst used in the method.

[Problems to be Solved by Prior Art and Invention]

It has been conventionally known to use a two-component catalyst composed of a contact product of (A) a titanium compound and (B) an organoaluminum compound and a condensing agent when polymerizing styrene or a styrene derivative (JP-A-62-62). -187708).

However, the above-mentioned catalyst has a drawback that the catalyst component is expensive and has a problem that it does not exhibit sufficient activity.

In the conventional method, in preparing the above-mentioned catalyst component (B), after filtering the solid matter from the reaction mixture, the solvent was simply distilled off at room temperature.

By the way, the catalyst component (B) usually contains an alkylaluminoxane, but contains an unreacted organoaluminum compound together with a chain or cyclic alkylaluminoxane. Since this organoaluminum compound is coordinate-bonded with aluminoxane to form a complex, it cannot be distilled off by ordinary room temperature vacuum distillation, and the aluminoxane as a condensation product cannot be purified with high purity.

Therefore, the present inventors have improved the activity of the above catalyst,
We have conducted intensive research to develop a more efficient method for producing a styrene polymer.

[Means for solving the problem]

As a result, they have found that by using a heat-treated product of a contact product of an organoaluminum compound and water as the component (B), the catalytic activity can be dramatically improved and the above problems can be solved. The present invention has been completed based on such findings.

That is, the present invention provides (A) a titanium compound and (B)
In a catalyst for producing a styrenic polymer comprising a contact product of an organoaluminum compound and water, after the contact reaction of the organoaluminum compound as component (B) and water, the obtained contact product is treated at 30 ° C to 200 ° C. The present invention provides a catalyst for producing a styrenic polymer, characterized by using a product heat-treated at a temperature of 20 ° C for 20 minutes to 8 hours.

The catalyst of the present invention contains the above-mentioned components (A) and (B) as main components, and there are various titanium compounds as the component (A). For example, the general formula TiR ¹ _a R ² _b R ³ _c R ⁴ _{4- (a + b + c)} ... (I) or TiR ¹ _d R ² _e R ³ _{3- (d + e)} ... (II ) [In the formula, R ¹ , R ² , R ³ and R ⁴ are a hydrogen atom and a carbon number 1 respectively.
To alkyl group having 1 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, aryl group having 6 to 20 carbon atoms, alkylaryl group, arylalkyl group, acyloxy group having 1 to 20 carbon atoms, cyclopentadienyl group, substituted cyclopenta Indicates a dienyl group, an indenyl group or a halogen atom. a, b, and c each represent an integer of 0 to 4, and d and e each represent an integer of 0 to 3. ] At least one compound selected from the group consisting of titanium compounds and titanium chelate compounds represented by:

R ¹ , R ² , R ³ and R ⁴ in the general formula (I) or (II) are each a hydrogen atom, an alkyl group having 1 to 20 carbon atoms (specifically, a methyl group, an ethyl group, a propyl group, Butyl group, amyl group, isoamyl group, isobutyl group, octyl group, 2-ethylhexyl group, etc., alkoxy group having 1 to 20 carbon atoms (specifically, methoxy group, ethoxy group, propoxy group, butoxy group, amyloxy group, Hexyloxy group, phenoxy group, 2-ethylhexyloxy group, etc.), 6 to 20 carbon atoms
Aryl group, alkylaryl group, arylalkyl group (specifically, phenyl group, tolyl group, xylyl group, benzyl group, etc.), C1-20 acyloxy group (specifically, heptadecylcarbonyloxy group, etc.) , Cyclopentadienyl group, substituted cyclopentadienyl group (specifically, methylcyclopentadienyl group, 1,2-dimethylcyclopentadienyl group, pentamethylcyclopentadienyl group, etc.), indenyl group or halogen Indicates an atom (chlorine, bromine, iodine, fluorine). These R ¹ , R ² , R ³ and R ⁴
May be the same or different.
Furthermore, a, b, and c each represent an integer of 0 to 4, and d and e each represent an integer of 0 to 3.

Specific examples of the tetravalent titanium compound and the titanium chelate compound represented by the general formula (I) include methyltitanium trichloride, titanium tetramethoxide, titanium tetraethoxide, titanium monoisopropoxy trichloride, titanium diisotate. Propoxy dichloride, titanium triisopropoxy monochloride, tetra (2-ethylhexyloxy) titanium, cyclopentadienyl titanium trichloride, biscyclopentadienyl titanium dichloride, cyclopentadienyl titanium trimethoxide, cyclopentadienyl trimethyl titanium , Pentamethylcyclopentadienyltitanium trimethoxide, pentamethylcyclopentadienyltrimethyltitanium, titanium tetrachloride Titanium tetrabromide, bis (2,4
Pentane dionato) titanium oxide, bis (2,
4-pentanedionato) titanium dichloride, bis (2,4-pentanedionato) titanium dibutoxide and the like can be mentioned.

As the titanium compound as the component (A), in addition to the above, a general formula [In the formula, R ⁵ and R ⁶ are each a halogen atom and a carbon number of 1 to 20.
And an alkoxyl group and an acyloxy group, and k is 2 to 20. ] A condensed titanium compound represented by the following may be used.

Further, the titanium compound may be used in the form of a complex with an ester or ether. The trivalent titanium compound represented by the general formula (II), which is another type of the component (A), is typically titanium trihalide such as titanium trichloride, cyclopentadienyl such as cyclopentadienyl titanium dichloride. Examples thereof include titanium compounds, and those obtained by reducing tetravalent titanium compounds. These trivalent titanium compounds may be used in the form of a complex with an ester or ether.

On the other hand, the component (B), which constitutes the main component of the catalyst together with the component (A), is obtained by heat-treating contact products of various organoaluminum compounds and water. The organoaluminum compound used as a raw material is generally represented by the general formula AlR ⁷ ₃ ... (a) [In the formula, R ⁷ represents an alkyl group having 1 to 8 carbon atoms. ] Organoaluminum compounds represented by the following, specifically, trimethylaluminum, triethylaluminum, triisobutylaluminum and the like can be mentioned, and among them, trimethylaluminum is most preferable.

The water to be brought into contact with such an organoaluminum compound may be ordinary water, ice or various water-containing compounds such as solvent-saturated water, adsorbed water of inorganic substances or water of crystallization containing metal salts such as CuSO ₄ .5H ₂ O. Good.

Examples of the reaction product of an organoaluminum compound such as alkylaluminum and water as a representative of the component (B) are specifically represented by the general formula (Wherein n represents the degree of polymerization) or a chain alkylaluminoxane represented by the general formula There is a cyclic alkylaluminoxane having a repeating unit represented by

In general, the contact product of an organoaluminum compound such as trialkylaluminum and water is water, along with the above-mentioned chain alkylaluminoxane and cyclic alkylaluminoxane, unreacted trialkylaluminum, a mixture of various condensation products, and further these. Molecules are intricately associated with each other, and they are various products depending on the contact conditions of trialkylaluminum and water.

The reaction between the organoaluminum compound and water at this time is not particularly limited, and the reaction may be performed according to a known method. For example, a method in which an organoaluminum compound is dissolved in an organic solvent and brought into contact with water, a method in which an organoaluminum compound is initially added at the time of polymerization and then water is added, and further, a metal salt is contained. There is a method of reacting water of crystallization, water adsorbed on an inorganic substance or an organic substance with an organoaluminum compound. Although this reaction proceeds in the absence of a solvent, it is preferably carried out in a solvent, and preferable solvents include aliphatic hydrocarbons such as hexane, heptane, and decane, or aromatic hydrocarbons such as benzene, toluene, and xylene. Can be raised.

To produce the catalyst of the present invention, after the above catalytic reaction,
When a water-containing compound is used, the solid residue is filtered off, and the filtrate is heated under normal pressure or reduced pressure at a temperature of 30 to 200 ° C., preferably 40 ° C. to 150 ° C., for 20 minutes to 8 hours, preferably 3
The heat treatment is performed while distilling off the solvent and the unreacted organoaluminum compound in the range of 0 minutes to 5 hours. In this heat treatment, the temperature may be appropriately set according to various situations,
Usually, it is carried out within the above range. Generally, if the temperature is lower than 30 ° C., the effect is not exhibited, and if it exceeds 200 ° C., thermal decomposition of the aluminoxane itself occurs, which is not preferable.

The reaction product may be obtained in the form of a colorless solid or solution depending on the treatment conditions of the heat treatment. The product thus obtained can be used as a catalyst solution after being dissolved or diluted with a hydrocarbon solvent, if necessary.

The catalyst of the present invention contains the above-mentioned components (A) and (B) as main components, and in addition to the above components, other catalyst components such as other organometallic compounds may be added if desired. When using this catalyst, (A) in the catalyst
The ratio of the component to the component (B) varies depending on various conditions and is not uniquely determined, but usually the ratio of aluminum in the component (B) to titanium in the component (A), that is, aluminum / titanium ( Molar ratio) as 1 to 10 ⁶ , preferably 1
0 to 10 ^4.

The catalyst of the present invention as described above exhibits high activity mainly in the production of a styrene polymer having a syndiotactic structure. This is presumably because the unreacted alkylaluminum remaining in the aluminoxane is removed by heat treatment of the contact product of the organoaluminum compound and water, and the purity of the aluminoxane increases.

Therefore, the present invention further provides a method for producing a styrenic polymer using the above catalyst.

To produce a styrenic polymer by the method of the present invention, styrene and / or a styrene derivative (alkylstyrene, alkoxystyrene, halogenated compound) is prepared in the presence of a catalyst containing the above-mentioned components (A) and (B) as a main component. Styrene-based monomers such as styrene and vinyl benzoate) are polymerized (or copolymerized), but this polymerization may be in bulk, and aliphatic hydrocarbons such as pentane, hexane and heptane, and alicyclic hydrocarbons such as cyclohexane. Alternatively, it may be carried out in an aromatic hydrocarbon solvent such as benzene, toluene or xylene. The polymerization temperature is not particularly limited, but is generally -30 ° C to + 120 ° C, preferably -10 ° C to + 100 ° C.

Further, in order to control the molecular weight of the obtained styrene polymer, it is effective to carry out the polymerization reaction in the presence of hydrogen.

The styrene-based polymer thus obtained mainly has a syndiotactic structure. here,
The predominantly syndiotactic structure in the styrene-based polymer means that the stereochemical structure is predominantly a syndiotactic structure, that is, a phenyl group or a substituted phenyl group, which is a side chain with respect to the main chain formed from carbon-carbon bonds, alternates. It means that it has a three-dimensional structure located in the opposite direction, and its tacticity is based on the nuclear magnetic resonance method ( ¹³ C-N
MR method). Tacticity measured by the ¹³ C-NMR method can be indicated by the abundance ratios of a plurality of continuous constitutional units, for example, two diads, three triads, and five pentads. However, the "predominantly styrene-based polymer having a syndiotactic structure" in the present invention is usually a diad.
Polystyrene, poly (alkylstyrene), poly (halogenated styrene), poly having a syndiotacticity of 75% or more, preferably 85% or more, or pentad (racemic pentad) 30% or more, preferably 50% or more (Alkoxystyrene), poly (vinylbenzoic acid ester) and mixtures thereof, or copolymers containing these as the main components, where poly (alkylstyrene) is poly (methylstyrene),
There are poly (ethyl styrene), poly (isopropyl styrene), poly (tertiary butyl styrene), etc.,
Examples of poly (halogenated styrene) include poly (chlorostyrene), poly (bromostyrene), and poly (fluorostyrene). Also, poly (alkoxystyrene)
Examples thereof include poly (methoxystyrene) and poly (ethoxystyrene). Of these, particularly preferable styrene polymers include polystyrene, poly (p-methylstyrene), poly (m-methylstyrene), and poly (p-
Examples thereof include tertiary butyl styrene), poly (p-chlorostyrene), poly (m-chlorostyrene), poly (p-fluorostyrene), and further a copolymer of styrene and p-methylstyrene.

The styrenic polymer produced by the method of the present invention,
Generally a number average molecular weight of 1,000 to 5,000,000, preferably 50,0
00 to 4,000,000, which has a high syndioctacity as described above, but after polymerization, if necessary, deashing with a washing liquid containing hydrochloric acid, etc., and further washing and drying under reduced pressure, such as methyl ethyl ketone If the soluble matter is removed by washing with the solvent described above and the obtained insoluble matter is further treated with chloroform or the like, a high-purity styrene polymer having extremely large syndiotacticity can be obtained.

〔Example〕

 Next, the present invention will be described in more detail with reference to examples.

Example 1 (1) Preparation of heat-treated aluminoxane 74 g (0.30 mol) of copper sulfate pentahydrate (CuSO ₄ .5H ₂ O) and toluene were placed in a glass container having an inner volume of 1000 ml and purged with argon.
500 ml and 74 ml (0.78 mol) of trimethylaluminum were added, and the mixture was reacted at 20 ° C for 30 hours. Then, the solution obtained by removing the solid portion was heat-treated at 110 ° C. for 2 hours under reduced pressure. As a result, toluene and unreacted trimethylaluminum were distilled off to obtain 17.7 g of a colorless glassy contact product (aluminoxane).

 This was dissolved in 50 ml of toluene and used as a catalyst component.

(2) Polymerization of styrene In a reaction vessel having an internal volume of 500 ml, 200 ml of heptane, 6 mmol of the aluminoxane obtained in (1) above as an aluminum atom, 0.06 mmol of pentamethylcyclopentadienyl titanium trimethoxide and 50 ml of styrene.
Was added and the polymerization reaction was carried out at 70 ° C. for 1 hour.

After the reaction was completed, the product was washed with a hydrochloric acid-methanol mixed solution to decompose and remove the catalyst component, and dried to obtain 9.86 g of a polymer (polystyrene). The syndiotacticity of this polymer in racemic pentad was 98% by ¹³ C-NMR measurement.

Examples 2-4 and Comparative Examples 1-2 Except that the heat treatment conditions were changed to those shown in Table 1,
The same operation as in Example 1 (1) was performed to obtain a catalyst component.

Next, Example 1 was repeated except that this catalyst component was used.
The same operation as in (2) was performed to give a polymer (polystyrene).
I got The results are shown in Table 1.

[Effect of the Invention] As described above, the catalyst of the present invention removes unreacted alkylaluminum, which is a catalyst poison, by heat treatment and contains a high-purity aluminoxane, and therefore exhibits a remarkably high activity. Therefore, if a styrene-based monomer is polymerized using this catalyst, a styrene-based polymer with high syndiotacticity can be efficiently produced.

The syndiotactic styrene-based polymer thus obtained has excellent physical properties such as heat resistance and chemical resistance, and is widely and effectively used in various applications.

Claims (3)

[Claims] 1. A catalyst for producing a styrene polymer comprising a contact product of (A) a titanium compound and (B) an organoaluminum compound with water, and a catalytic reaction of the organoaluminum compound with water as the component (B). A catalyst for producing a styrene-based polymer, characterized in that the product obtained by subjecting the obtained contact product to heat treatment at a temperature of 30 ° C. to 200 ° C. for 20 minutes to 8 hours is used. 2. A method for producing a styrene-based polymer, which comprises using the catalyst according to claim 1 in polymerizing styrene and / or a styrene derivative. 3. The styrene-based polymer is a styrene-based polymer mainly having a syndiotactic structure.
The manufacturing method described.