JPH0813852B2 - 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 for polymerizing styrene and / or a styrene derivative (special characteristics Kaisho 62-187708
Issue).

These two-component catalysts are used for polymerization by contacting and reacting in the reaction vessel immediately before the polymerization reaction, but using two kinds of catalysts is complicated in terms of operation and equipment. Is. However, there is a problem that the catalyst is modified by simply mixing the titanium compound and the organoaluminum compound, and the catalyst is deactivated after a certain period of time.

Therefore, the present inventors have mainly proposed a method for more efficiently producing a styrene-based polymer having a syndiotactic structure, and a highly active method that is easy to prepare and does not deactivate even if stored for a long time after preparation. We have conducted intensive research to develop a catalyst for producing a styrene polymer.

[Means for solving the problem]

As a result, the contact product obtained by adding the titanium compound and further reacting at the same time as the contact reaction between the organoaluminum compound and water or when the reaction proceeds to some extent does not deactivate even when stored for a long time. It has been found that it is suitable for the above purpose. The present invention has been completed based on such findings.

That is, the present invention provides a catalyst for producing a styrene-based polymer, which comprises a contact product of an organoaluminum compound and a titanium compound and water.

The catalyst of the present invention is mainly composed of a contact product of an organoaluminum compound and a titanium compound with water. Here, the organoaluminum compound can be applied to various organoaluminum compounds, but usually, the general formula AlR ₃ [wherein, R 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.

There are various titanium compounds.
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. 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, in addition to the above, the 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.

A trivalent titanium compound represented by the general formula (II), which is another type of the above components, is typically a titanium trihalide such as titanium trichloride, a cyclopentadienyl titanium compound such as cyclopentadienyl titanium dichloride. Other examples include those obtained by reducing a tetravalent titanium compound. These trivalent titanium compounds are esters,
You may use what formed the complex with ether etc.

The catalyst of the present invention is obtained by catalytically reacting the above-mentioned organoaluminum compound and titanium compound with water, and the water may be ordinary water, ice or various water-containing compounds, for example, solvent saturated water. , Inorganic water or
Crystal water containing a metal salt such as CuSO ₄ .5H ₂ O is used.

In order to produce the catalyst of the present invention, the above-mentioned organoaluminum compound and water are placed in an inert hydrocarbon solvent such as an aliphatic hydrocarbon such as hexane, heptane or decane or an aromatic hydrocarbon such as benzene, toluene or xylene. The catalytic reaction is carried out by adding the titanium compound at the same time as the catalytic reaction or when the catalytic reaction proceeds to some extent. The degree of progress of the reaction can be determined by the amount of alkane gas generated (1 molecule of alkylaluminum to 3 molecules of alkane can be generated).

After the completion of such a contact reaction, the solid matter may be filtered, if necessary, and then dried under reduced pressure at room temperature, and the solid matter may be redissolved in an appropriate hydrocarbon solvent and used as a polymerization catalyst.

The use ratio of the aluminum compound and the titanium compound in preparing the catalyst of the present invention is not uniquely defined because it varies depending on various conditions, but usually the ratio of aluminum atom / titanium atom is 5 to 10 ⁶ , preferably It should be 10 to 10 ⁴ .

The catalyst of the present invention is mainly composed of the contact product as described above, and in addition to the above, optionally other catalyst components, for example, the general formula AlR ⁷ ₃ [wherein R ⁷ has 1 to 1 carbon atoms]. 8 represents an alkyl group. ] It is also possible to add a trialkylaluminum represented by the above or other organometallic compounds.

The catalyst of the present invention as described above exhibits high activity mainly in the production of a styrene polymer having a syndiotactic structure.

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 (alkyl styrene, alkoxy styrene, halogenated styrene, vinyl benzoate ester) is prepared in the presence of a catalyst containing the above-mentioned components as a main component. Etc.) and the like are polymerized (or copolymerized) with each other, but the polymerization may be in the form of a block, and an aliphatic hydrocarbon such as pentane, hexane, heptane, an alicyclic hydrocarbon such as cyclohexane, or benzene, toluene, xylene. It may be carried out in an aromatic hydrocarbon solvent such as. The polymerization temperature is not particularly limited, but is generally -30
C. to + 120.degree. C., preferably -10.degree. C. to + 100.degree.

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 and Comparative Examples.

Example 1 (1) Preparation of contact product In a glass container having an internal volume of 1000 ml and substituted with argon, 60 g of copper sulfate pentahydrate (CuSO ₄ .5H ₂ O) (0.24 mol) and toluene
The reaction was started at 20 ° C by adding 500 ml and 60 ml (0.63 mmol) of trimethylaluminum. When the amount of methane gas generated reached 18.5 l (750 mmol), 1.5 mmol of cyclopentadienyl titanium trichloride was dissolved in 100 ml of toluene and added. The reaction was further continued at 20 ° C., and when the total amount of methane gas generated reached 35.6 l (1.45 mol), the solid matter was filtered off. Then, the filtrate was dried under reduced pressure at room temperature to obtain 20.9 g of a catalyst (contact product).

This was redissolved in 100 ml of toluene to obtain a catalyst solution. The ratio of Al atoms to Ti atoms contained in this solution was 408: 1.

(2) Polymerization of styrene In a reaction vessel having an internal volume of 500 ml, 100 ml of toluene and the catalyst (catalytic product) obtained in the above (1) as titanium atom were used.
Add 025 mmol and 150 mmol of styrene, and add 1 at 50 ° C.
The polymerization reaction was carried out for a time.

After completion of the reaction, the product was washed with a hydrochloric acid-methanol mixed solution to decompose and remove the catalyst component, and dried to obtain 12.5 g of a polymer (polystyrene).

The polymerization activity of the catalyst is 10.4 kg / g.Ti, and the syndiotacticity of this polymer in racemic pentad is
It was found to be 98% by ¹³ C-NMR measurement.

The polymerization activity did not change even 2 weeks after the catalyst was prepared.

Comparative Example 1 (1) Preparation of contact product (aluminoxane) Solid (aluminoxane) 19.5 g was prepared in the same manner as in Example 1 (1) except that cyclopentadienyltitanium trichloride was not added. Got

(2) Polymerization of styrene Cyclopentanedienyl titanium trichloride
3 mmol and aluminoxane of the above (1) with Al atom 12.
The mixture was brought into contact with 2 mmol and kept at room temperature for 2 weeks to obtain a two-component catalyst.

Then, styrene was polymerized in the same manner as in Example 1 (2) except that this two-component catalyst was used to obtain 0.5 g of a polymer (polystyrene). The polymerization activity of this catalyst is 0.
It was 4 kg / g · Ti, and the syndiotacticity of this polymer in racemic pentad was found to be 85% by ¹³ C-NMR measurement.

Example 2 (1) Preparation of contact product Example 1 except that 1.5 mmol of titanium tetraethoxide was added from the beginning as a titanium compound.
Performing the same operation as in (1), the catalyst (contact product) 19.8
got g.

This was redissolved in 100 ml of toluene to obtain a catalyst solution.
The ratio of Al atoms to Ti atoms contained in this solution was 390: 1.

(2) Polymerization of styrene Polymerization of styrene was carried out in the same manner as in Example 1 (2) except that the catalyst obtained in Example 2 (1) was used to obtain 7.2 g of a polymer (polystyrene). . The polymerization activity of this catalyst is
It was found to be 6.0 kg / g · Ti, and the syndiotacticity of this polymer in racemic pentad was found to be 98% by ¹³ C-NMR measurement.

The polymerization activity of this catalyst did not change even 2 weeks after the catalyst was prepared.

Comparative Example 2 (1) Preparation of catalyst product Titanium tetraethoxide (0.3 mmol) was contacted with the aluminoxane (117 mmol) of Comparative Example 1 (1) and kept at room temperature for 2 weeks to prepare a contact product.

(2) Polymerization of styrene Except for using the contact product obtained in the above Example 2 (1), styrene was polymerized in the same manner as in Example 1 (2) to obtain 0.3 g of a polymer (polystyrene). Obtained. The polymerization activity of this catalyst (catalytic product) was 0.3 kg / g · Ti, and the syndiotacticity of this polymer in racemic pentad was 87% by ¹³ C-NMR measurement. It was

Example 3 (1) Preparation of contact product The same as Example 1 (1) except that 1.5 mmol of pentamethylcyclopentadienyltitanium trimethoxide was used in place of cyclopentadienyltitanium trichloride. Operate the catalyst (contact product)
21.1 g was obtained. This was redissolved in 100 ml of toluene to obtain a catalyst solution. The ratio of Al atoms and Ti atoms contained in this solution is
It was 395: 1.

(2) Polymerization of Styrene Polymerization of styrene was carried out in the same manner as in Example 1 (2) except that the contact product obtained in Example 3 (1) was used to obtain 14.0 g of a polymer (polystyrene). Obtained. The polymerization activity of this catalyst (contact product) was 11.7 kg / g · Ti, and the syndiotacticity of this polymer in racemic pentad was found to be 98% by ¹³ C-NMR measurement. It was

The polymerization activity of this catalyst did not change even 2 weeks after the catalyst was prepared.

Comparative Example 3 (1) Preparation of contact product Pentamethylcyclopentadienityltitanium trimethoxide 0.2 mmol was contacted with 79 mmol of the aluminoxane of the above Comparative Example 1 (1) and kept at room temperature for 2 weeks to obtain a contact product. Was prepared.

(2) Polymerization of Styrene Polymerization of styrene was carried out in the same manner as in Example 1 (2) except that the contact product obtained in Comparative Example 3 (1) was used to obtain 0.6 g of a polymer (polystyrene). Obtained. The polymerization activity of this catalyst (contact product) was 0.5 kg / g · Ti, and the syndiotacticity of this polymer in racemic pentad was found to be 90% by ¹³ C-NMR measurement. It was

〔The invention's effect〕

As described above, the catalyst of the present invention is obtained by adding a titanium compound when a contact product of an organoaluminum compound and water is prepared. The compound is effectively used, and the catalyst complex is efficiently formed. Further, since the titanium complex is surrounded and surrounded by the aluminum compound, deactivation of the catalyst complexes is unlikely to occur. Therefore, the catalyst of the present invention has high activity even after being stored for a long time. Therefore, if a styrene-based monomer is polymerized using this catalyst, a styrene-based polymerization having high syndiotacticity can be efficiently produced by a simple operation.

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-based polymer, which comprises a contact product of an organoaluminum compound and a titanium compound and water. 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.