JPH0757767B2 - Method for producing styrene polymer and 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. More specifically, the stereochemical structure of the polymer chain is mainly a syndiotactic structure. The present invention relates to a method for efficiently producing the styrene-based polymer and a catalyst used in the method.

[Problems to be Solved by Prior Art and Invention]

Conventionally, as styrene-based polymers, those having stereotactic structures of atactic structure and isotactic structure are known, but those of syndiotactic structure are known.
A styrene polymer having a particularly high syndiotactic structure has not been known.

Recently, the group of the present inventors succeeded in developing a styrene-based polymer having a stereochemical structure mainly having a syndiotactic structure, and one of the production methods thereof was disclosed in JP-A-62-187708.
Disclosed in Japanese Patent Publication No. However, the catalyst used in this method was not only high in cost, but also did not show sufficiently high activity, and the molecular weight of the obtained polymer was not so high.

Therefore, the inventors of the present invention have conducted extensive studies mainly to develop a method for more efficiently producing a styrene polymer having a syndiotactic structure and a catalyst with improved activity.

[Means for Solving the Problems]

As a result, by using a combination of a specific titanium compound and a specific catalyst product as a catalyst,
It has been found that the activity is remarkably improved and the production efficiency of the target styrene polymer having a syndiotactic structure is dramatically improved. The present invention has been completed based on such findings.

That is, the present invention provides (A) the general formula TiRXYZ [wherein R represents a cyclopentadienyl group, a substituted cyclopentadienyl group or an indenyl group, and X, Y and Z each independently have 1 to 12 carbon atoms. Alkyl group of 1 to 12 carbon atoms
Alkoxy group, aryl group having 6 to 20 carbon atoms, 6 carbon atoms
Represents an aryloxy group having 20 to 20 carbon atoms, an arylalkyl group having 6 to 20 carbon atoms, or halogen. Titanium compound and represented by] (B) a contact product of trimethylaluminum and water, aluminum observed by proton nuclear magnetic resonance absorption method - methyl (Al-CH ₃₎ methyl proton signal region based on binding And a high magnetic field component of 50% or less in the high magnetic field component.

The catalyst of the present invention is mainly composed of the following components (A) and (B). Here, the component (A) is represented by the general formula TiRXYZ ... (I) [Formula In the formula, R represents a cyclopentadienyl group, a substituted cyclopentadienyl group or an indenyl group, and X, Y and Z each independently represent an alkyl group having 1 to 12 carbon atoms and 1 to 12 carbon atoms.
Alkoxy group, aryl group having 6 to 20 carbon atoms, 6 carbon atoms
Represents an aryloxy group having 20 to 20 carbon atoms, an arylalkyl group having 6 to 20 carbon atoms, or halogen. ] It is a titanium compound represented by. In this formula, the substituted cyclopentadienyl group represented by R has, for example, 1 to 1 carbon atoms.
A cyclopentadienyl group substituted with one or more alkyl groups of 6, specifically, a methylcyclopentadienyl group, 1,2
A dimethylcyclopentadienyl group and a pentamethylcyclopentadienyl group. Further, X, Y and Z are each independently an alkyl group having 1 to 12 carbon atoms (specifically, methyl group, ethyl group, propyl, n-butyl group, isobutyl group,
Amyl group, isoamyl group, octyl group, 2-ethylhexyl group, etc., alkoxy group having 1 to 12 carbon atoms (specifically, methoxy group, ethoxy group, propoxy group, putoxy group, amyloxy group, hexyloxy group, octyloxy group) Base, 2
-Ethylhexyloxy group, etc.), C6-C20 aryl group (specifically, phenyl group, naphthyl group, etc.), C6-C20 aryloxy group (specifically, phenoxy group, etc.), C6 To 20 arylalkyl groups (specifically benzyl groups) or halogens (specifically chlorine, bromine, iodine or fluorine).

Specific examples of the titanium compound represented by the general formula (I) include cyclopentadienyl trimetal titanium, cyclopentadienyl triethyl titanium, cyclopentadienyl tripropyl titanium, cyclopentadienyl tributyl titanium, penta Methylcyclopentadienyl trimethyl titanium, pentamethyl cyclopentadienyl triethyl titanium, pentamethyl cyclopentadienyl tripropyl titanium, pentamethyl cyclopentadienyl tributyl titanium, cyclopentadienyl methyl titanium dichloride, cyclopentadienyl ethyl titanium Dichloride, pentamethylcyclopentadienylmethyl titanium dichloride, pentamethyl cyclopentadienyl ethyl titanium dichloride, cyclopentadienyl dimethyl titanium monochloride Cyclopentadienyl diethyl titanium monochloride, cyclopentadienyl titanium trimethoxide, cyclopentadienyl titanium triethoxide, pentamethylcyclopentadienyl titanium trimethoxide, pentamethylcyclopentadienyl titanium triethoxide, penta Methylcyclopentadienyl titanium tripropoxide, cyclopentadienyl monomethoxy titanium dichloride, cyclopentadienyl dimethoxy titanium monochloride, pentamethyl cyclopentadienyl monomethoxy titanium dichloride, cyclopentadienyl titanium triphenoxide, pentamethyl cyclo Pentadienyl titanium triphenoxide, cyclopentadienyl diphenoxy titanium monochloride, pentamethyl cyclopentadienyl diphenoxy titanium mono Rorido cyclopentadienyl mono phenoxy titanium dichloride, pentamethylcyclopentadienyl mono phenoxy titanium dichloride, cyclopentadienyl tribenzyl titanium, cyclopentadienyl methyl dibenzyl titanium, pentamethylcyclopentadienyl tribenzyl titanium,
Pentamethyldiethoxymethyl titanium, indenyl titanium trimethoxide, indenyl titanium triethoxide,
Examples thereof include indenyl trimethyl titanium and indenyl tribenzyl titanium. As Among them preferred the general formula TiRX ¹ ₃ ··· (II) [wherein, R represents a cyclopentadienyl group, substituted cyclopentadienyl group or indenyl group, X ¹ is 1 to the number of carbon atoms
A 12-alkyl group, a C1-C12 alkoxy group, a C6-C20 aryl group, a C6-C20 aryloxy group, and a C6-C20 arylalkyl group are shown. ] The titanium compound represented by these is mentioned.

On the other hand, a contact product of trimethylaluminum and water is used as the component (B) which constitutes the main component of the catalyst together with the component (A). This contact product usually contains methylaluminoxane, but this methylaluminoxane has the general formula (Wherein n represents an integer of 2 to 50) or a chain methylaminoxane represented by the general formula Cyclic methylaluminoxane (polymerization degree 2 to 52) having a repeating unit represented by

Generally, the contact product of trimethylaluminum and water is unreacted trimethylaluminum, a mixture of various condensation products, and a molecule in which these are intricately associated, together with the above-mentioned chain methylaluminoxane and cyclic methylaluminoxane. However, these are various products depending on the contact condition between trimethylaluminum and water. Of these, in the present invention, the contact product of the trimethylaluminum with water used as the component (B) of the catalyst, of aluminum is observed by proton nuclear magnetic resonance absorption method - methyl (Al-CH ₃₎ based on the binding The high magnetic field component in the methyl proton signal region is 50% or less. In other words, when the proton nuclear magnetic resonance ( ¹ H-NMR) spectrum of the above contact product is observed in a toluene-like medium at room temperature, the methyl proton signal based on Al-CH ₃ is tetramethylsilane (TMS). It is found in the range of 1.0 to −0.5 ppm in the standard. TMS proton signal (0ppm) is Al-C
Since it is in the methyl proton observation region based on H ₃ , this Al-
The CH ₃ -based methyl proton signal was measured with reference to the toluene methyl proton signal of 2.35 ppm in the TMS standard, and the high magnetic field component (that is, −0.1 to −0.5 ppm) and other magnetic field components (that is, 1.0 to 0.1 ppm) were measured. ppm),
The high magnetic field component of 50% or less, preferably 45 to 5%, is used as the component (B) of the catalyst of the present invention. If the component having a high magnetic field of more than 50% of the total is used as the component (B) of the catalyst, the activity is lowered and the styrene polymer having a desired syndiotactic structure cannot be efficiently produced.

This contact product of trimethylaluminum and water can be prepared by various methods, for example, a method of dissolving trimethylaluminum in an organic solvent and then contacting this with water, initially adding trimethylaluminum during polymerization. There is a method of adding water later, and a method of reacting crystallization water contained in a metal salt or the like, or water adsorbed to an inorganic substance or an organic substance with trimethylaluminum.

In the above contact operation, the above-mentioned high magnetic field component is
Although it is not always possible to specify the value so as to be less than or equal to%, it is not always possible to specify, but generally, conditions such as lengthening the contact reaction time, raising the temperature of the contact reaction, and increasing the ratio of water to trimethylaluminum are selected. Preferably.

In addition to the components (A) and (B) described above, the catalyst according to the present invention may further have other desired catalyst components such as the general formula AlR '
₃ (In the formula, R'represents an alkyl group having 1 to 8 carbon atoms.)
It is also possible to add a trialkylaluminum represented by and other organic metal compounds. When this catalyst is used, the ratio of the component (A) to the component (B) in the catalyst varies depending on various conditions and is not uniquely determined, but usually it is the same as aluminum in the component (B) ( Ratio of titanium in component A), that is, aluminum / titanium (molar ratio)
Is 1 to 10 ⁴ , preferably 10 to 10 ³ .

The catalyst of the present invention as described above exhibits a 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,
Polymerization of styrene-based monomers such as styrene and / or styrene derivatives (alkylstyrene, alkoxystyrene, halogenated styrene, vinyl benzoate, etc.) in the presence of a catalyst containing the above-mentioned components (A) and (B) as a main component. (Or copolymerization), but this polymerization may be performed in bulk, in an aliphatic hydrocarbon such as pentane, hexane, heptane, an alicyclic hydrocarbon such as cyclohexane, or an aromatic hydrocarbon solvent such as benzene, toluene, xylene. You can go. The polymerization temperature is not particularly limited, but is generally -30 to 120 ° C, preferably -10 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 a styrene-based polymer means that the stereo-compounded structure is mainly a syndiotactic structure, that is, a phenyl group or a substituted phenyl group, which is a side chain, alternates with respect to the main chain formed from carbon-carbon bonds. It has a steric structure located in the opposite direction, and its tacticity is based on the nuclear magnetic resonance method ( ¹³ C-N
MR method). ^The tacticity measured by the ¹³ C-NMR method can be indicated by the abundance ratio of a plurality of continuous constitutional units, for example, diad in the case of 2, triad in the case of 3 and pentad in the case of 5. 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 has a weight average molecular weight of 5,000 or more, preferably 10,000 to 20,
, 000,000, number average molecular weight 2,500 or more, preferably 5,000 to 1
Although it is 0,000,000 and has high cycioctaticity as described above, after polymerization, if necessary, deashing is performed with a washing liquid containing hydrochloric acid, etc., and further washing and reduced pressure drying are followed by a solvent such as methyl ethyl ketone. Soluble matter is removed by washing with, and the obtained insoluble matter is further treated with chloroform or the like to obtain a high-purity styrene polymer having extremely high syndiotacticity.

〔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 of trimethylaluminum and water 17.8 g (71 mmol) of toluene and copper sulfate pentahydrate (CuSO ₄ .5H ₂ O) were placed in a glass container having an inner volume of 500 ml and purged with argon. 200 ml and 24 ml (250 mmol) of trimethylaluminum were added and reacted at 40 ° C. for 8 hours. Then, toluene was further distilled off from the solution obtained by removing the solid portion at room temperature under reduced pressure to obtain 6.7 g of a contact product. The molecular weight of this product measured by the freezing point depression method was 610. The high magnetic field component of the above according to the ¹ H-NMR measurement (i.e. -0.1
-0.5 ppm) was 43%.

(2) Production of styrenic polymer In a reaction vessel having an internal volume of 500 ml, 200 ml of heptane, the above (1)
8 mmol of the contact product obtained as above as an aluminum atom, 0.08 mmol of pentamethylcyclopentadienyl titanium trimethoxide and 50 ml of styrene were added, and a polymerization reaction was carried out at 50 ° C. for 2 hours. After the reaction was completed, the product was treated with hydrochloric acid-
It was washed with a mixed solution of methanol to decompose and remove the catalyst-produced component, and dried to obtain 25.0 g of a polymer. Next, this polymer was extracted with methyl ethyl ketone using a Soxhlet extractor, and an extraction residue (MIP) of 98.0% was obtained. The weight average molecular weight of the obtained polymer was 1.6 million, and the number average molecular weight was 66.2.
It was good. It was confirmed that the polymer obtained by melting point and ¹³ C-NMR measurements was polystyrene having a syndiotactic structure.

Example 2 The same operation as in Example 1 was carried out except that pentamethylcyclopentadienyl titanium triethoxide was used in place of pentamethyl cyclopentadienyl titanium trimethoxide in Example 1 (2). It was As a result, syndiotactic polystyrene having a weight average molecular weight of 1.62 million was obtained at a conversion rate of 44.7%.

Example 3 The same operation as in Example 1 except that pentamethylcyclopentadienyl ditertiary butoxy titanium monochloride was used in place of pentamethylcyclopentadienyl titanium trimethoxide in Example 1 (2). I went. As a result, syndiotactic polystyrene having a weight average molecular weight of 1.48 million was obtained at a conversion rate of 16.9%.

Example 4 (1) Preparation of contact product of trimethylaluminum and water The same operation as in Example 1 (1) was performed except that the reaction time was changed to 24 hours in Example 1 (1). as a result,
6.2 g of a contact product having a molecular weight of 750 and a high magnetic field component of 41% was obtained.

(2) Production of styrene-based polymer In Example 1 (2), the contact product obtained in Example 4 (1) was used, and cyclopentadiene was used instead of pentamethylcyclopentadienyl titanium trimethoxide. Example 1 except that phenyl titanium trimethoxide was used.
The same operation as in (2) was performed. As a result, syndiotactic polystyrene having a weight average molecular weight of 128,000 was obtained at a conversion of 75.2%.

Example 5 Syndiotactic by the same operation as in Example 4 (2) except that cyclopentadienyl titanium triethoxide was used in place of cyclopentadienyl titanium trimethoxide in Example 4 (2). Chick polystyrene 6
Obtained at a conversion of 8.6%.

Example 6 Example 4 (2) except that cyclopentadienyl titanium triphenoxide was used in place of cyclopentadienyl titanium trimethoxide in Example 4 (2).
Syndiotactic polystyrene
Obtained at a conversion of 60.3%.

Comparative Example 1 (1) Preparation of contact product of trimethylaluminum and water In Example 1 (1), trimethylaluminum was mixed with 3
4.6 mm (360 mmol), copper sulfate pentahydrate (CuSO ₄ / 5H ₂ O)
Was used in the same manner as in Example 1 (1) except that 29.4 g (117 mmol) was used and the reaction time was 3 hours. As a result, a contact product with a molecular weight of 470 and a high magnetic field component of 65%
Obtained 5.5 g.

(2) Production of Styrenic Polymer In Example 1 (2), using the contact product obtained in Comparative Example 1 (1), titanium tetraethoxide was used instead of pentamethylcyclopentadienyl titanium trimethoxide. The same operation as in Example 1 (2) was performed except that the above was used. As a result, syndiotactic polystyrene
It was obtained only at a conversion of 6.6%.

Conversion rate, yield, extraction residue (MIP) of the syndiotactic polystyrene obtained in Examples 1 to 6 and Comparative Example 1 above.
The weight average molecular weight (M _W ) is shown in Table 1 below.

Examples 7-10 200 ml of heptane in a reaction vessel having an internal volume of 500 ml, Example 1
The contact product obtained in (1) was 8 mmol as an aluminum atom, and the titanium compound shown in Table 2 below was added to 0.1 mmol.
08 mmol and 50 ml of styrene were added, and a polymerization reaction was carried out at 50 ° C. for 2 hours. 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 a polymer. Then, the polymer was extracted with methyl ethyl ketone using a Soxhlet extractor, and an extraction residue (MIP) of 98.0% was obtained. The weight average molecular weight of the obtained polymer was 1.45 million and the number average molecular weight was 662,000. This polymer was confirmed to be a polystyrene having a syndiotactic structure by melting point and ¹³ C-NMR measurement.

Table 2 shows the conversion rate, yield, extraction residue (MIP), weight average molecular weight (M _W ) and number average molecular weight (M _W ) of polystyrene obtained in each example.

[Effect of the Invention] As described above, the catalyst of the present invention has 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] (A) General formula TiRXYZ [wherein R represents a cyclopentadienyl group, a substituted cyclopentadienyl group or an indenyl group, and X, Y and Z each independently have 1 to 12 carbon atoms. Alkyl group, C1-12
Alkoxy group, aryl group having 6 to 20 carbon atoms, 6 carbon atoms
Represents an aryloxy group having 20 to 20 carbon atoms, an arylalkyl group having 6 to 20 carbon atoms, or halogen. Titanium compound and represented by] (B) a contact product of trimethylaluminum and water, aluminum observed by proton nuclear magnetic resonance absorption method - methyl (Al-CH ₃₎ methyl proton signal region based on binding A catalyst for producing a styrene-based polymer, which comprises a contact product having a high magnetic field component of 50% or less. 2. The high magnetic field component in the methyl proton signal region based on the aluminum-methyl group (Al—CH ₃ ) bond observed by the proton nuclear magnetic resonance absorption method is 2.35 ppm of the methyl proton of toluene under the toluene solvent measurement conditions. The catalyst for producing a styrenic polymer according to claim 1, which has a standard of -0.1 to -0.5 ppm. 3. 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.