JP2656928B2 - Method for producing styrenic polymer - Google Patents

Description

The present invention relates to a method for producing a styrenic polymer, and more specifically, to a styrenic polymer having a stereoregularity of a syndiotactic structure (hereinafter referred to as a styrenic polymer). , Syndiotactic polystyrene).

[Conventional technology]

Generally, a styrene-based polymer is produced by radical polymerization, anionic polymerization, cationic polymerization, or polymerization using a so-called Ziegler catalyst. Styrene-based polymers are theoretically divided into isotactic, syndiotactic and atactic structures depending on the stereoregularity of the branched chains. It is known that, among the above polymerization methods, a radical polymerization, an anion polymerization and a cationic polymerization yield a polymer having an atactic structure, while a polymerization using a Ziegler catalyst yields a polymer mainly having an isotactic structure.

In recent years, it has been revealed that polystyrene having a syndiotactic structure can be obtained using a catalyst in which a certain transition metal compound and an organometallic compound are combined. For example,
JP-A-62-104818 exemplifies titanium compounds such as titanium halide and alkoxytitanium as transition metal compounds useful for such catalysts, and organoaluminum compounds as organometallic compounds. further,
The publication and the polymer, the 36, 604 (August 1987), as the organic aluminum compound, methylaluminoxane has been demonstrated to be effective is the reaction product of trimethylaluminum and water. Preparation of methylaluminoxane are usually taken is a method of reacting water of crystallization contained trimethylaluminum, etc. CuSO ₄ · 5H ₂ O or _{Al 2 (SO 4) 3 ·} 15H 2 O. But,
In these methods, methylaminoxan is prepared in advance,
Next, the catalytic performance is exhibited for the first time by adding a titanium compound thereto. Further, many of the above titanium compounds are extremely unstable in the air and are inconvenient to handle.

In view of the problems of the prior art, the present inventors have conducted intensive studies to develop a catalyst that can be advantageously used for syndiotactic polystyrene synthesis. The present inventors have found that the reaction product is extremely effective and completed the present invention.

That is, an object of the present invention is to provide a method capable of industrially and advantageously producing syndiotactic polystyrene using a so-called Ziegler catalyst.

[Means for solving the problem]

Therefore, according to the present invention, there is provided a method for producing a styrene-based polymer having a stereoregularity of a syndiotactic structure, and this method comprises, as a polymerization catalyst, a titanium compound having water of crystallization. It is characterized in that a reaction product with an organoaluminum compound is used.

The titanium compound having water of crystallization useful in the present invention is Ti
_{(SO 4) 2 · 4H 2} O and Ti (SO ₄₎ a 3 _· 8H ₂ O, organic aluminum compound is trimethylaluminum.
These titanium compounds, an organic aluminum compound consisting of trimethyl aluminum, benzene, toluene,
A catalyst effective for polymerization in one step by reacting in an organic solvent such as an aromatic solvent such as xylene or an aliphatic solvent having 5 or more carbon atoms, preferably 6 to 12 carbon atoms such as hexane and heptane. A liquid can be prepared.

The obtained compound is easy to handle, and when it is used as a polymerization catalyst, reproducibility of polymerization is easily obtained.

In the method of the present invention, generally, polymerization can be carried out by directly adding a styrene monomer to the catalyst solution obtained as described above.

Examples of the styrene polymer obtainable by the method of the present invention include polystyrene, poly (p-methylstyrene), poly (m-methylstyrene), and poly (o-styrene).
Methylstyrene), poly (2,4-dimethylstyrene),
Poly (alkylstyrene) such as poly (2,5-dimethylstyrene), poly (3,4-dimethylstyrene), poly (3,5-dimethylstyrene), poly (pt-butylstyrene), and poly (p -Chlorostyrene), poly (m-chlorostyrene), poly (o-chlorostyrene), poly (p
-Bromostyrene), poly (m-bromostyrene), poly (o-bromostyrene), poly (p-fluorostyrene), poly (m-fluorostyrene), poly (o-fluorostyrene), poly (o-methyl) Poly (halogenated styrene) such as -p-fluorostyrene) and poly (p-fluorostyrene).
Chloromethylstyrene), poly (m-chloromethylstyrene), poly (halogen-substituted alkylstyrene) such as poly (o-chloromethylstyrene), poly (p-methoxystyrene), poly (m-methoxystyrene), poly (m-methoxystyrene) o-methoxystyrene), poly (p-ethoxystyrene), poly (m-ethoxystyrene), poly (alkoxystyrene) such as poly (o-ethoxystyrene), poly (p-carboxymethylstyrene), poly (m- Poly (carboxyesterstyrene) such as carboxymethylstyrene), poly (o-carboxymethylstyrene), poly (alkyl ether styrene) such as poly (p-vinylbenzylpropyl ether), and poly (p-trimethylsilylstyrene). (Alkylsilylstyrene), poly (vinyl) Ethylbenzene sulfonic acid), and poly (vinylbenzyl dimethoxyphosphoryl sulfide) and the like.

In general, the polymerization temperature is preferably room temperature to 80 ° C, and more preferably 30 to 60 ° C. The polymerization time varies depending on the concentrations of the catalyst and styrene and the catalytic activity, and usually varies between several minutes to several tens of hours.

〔Example〕

 Hereinafter, the present invention will be further described with reference to examples.

Example 1 (1) Preparation of catalyst component In a flask having a capacity of 300 ml, 25 g of Ti (SO ₄ ) ₃
・ 8H ₂ O and 43 ml of toluene at −20 ° C. under a nitrogen atmosphere
And stir to obtain a dispersion. To this, 1 in 150 ml of toluene
A solution of 5 g of (CH ₃ ) ₃ Al is added dropwise in 3 hours and reacted at -20 ° C. for 20 hours. The reaction mixture is then heated to room temperature,
Leave at room temperature for 96 hours. The reaction compound is filtered to remove the precipitate, and the filtrate is collected to obtain a catalyst solution.

When the titanium concentration and the aluminum concentration in the obtained catalyst solution were measured by atomic absorption spectroscopy, the titanium concentration was 1.35 × 10 ⁻⁵ mol / and the aluminum concentration was 0.26 mol /.

(2) Polymerization In a stainless steel autoclave having a capacity of 100 ml, 40 ml of the catalyst solution obtained above and 10 ml of styrene were charged at room temperature in a nitrogen stream, and the mixture was heated to 40 ° C. and polymerized for 48 hours with stirring. The polymerization was stopped by adding a mixture of methanol and hydrochloric acid into the reactor, and the resulting polymer was filtered, washed with methanol, and dried at room temperature. The yield of polymer is 0.
It was 05g.

The stereoregularity of the polymer obtained as described above was determined by using deuterated chloroform as a solvent and TMS as an internal standard to obtain ¹³ C
-Measured by NMR spectroscopy. FIG. 2 shows the obtained spectrum. As is clear from the figure, the polymer has a syndiotactic structure and has a very high syndiotacticity.

Example 2 A catalyst solution was prepared in the same manner as in Example 1, except that Ti (SO ₄ ) ₂ .4H ₂ O was used as the titanium compound. In the catalyst solution
The concentrations of Ti and Al were as follows, respectively.

Ti: 6.5 × 10 ^-5 mol / Al: 0.13 mol / 10 ml of styrene was added to 40 ml of this catalyst solution, and polymerization was carried out under the same conditions as in Example 1. Further, in the same manner as in Example 1, after the polymerization was stopped, the polymer was filtered, washed, and dried to obtain a polymer 0.1.
18 g were obtained. As a result of measuring the stereoregularity of this polymer by ¹³ C-NMR spectrum method, the same results as in Example 1 were obtained.
A spectrum with extremely high syndiotacticity was obtained.

Example 3 30 ml of styrene was added to 40 ml of the same catalyst solution as in Example 2, and
The reaction was performed at 10 ° C. for 10 hours. Then, in the same manner as in Example 1, after the polymerization was stopped, the polymer was filtered, washed, dried, and then polymerized.
0.49 g was obtained. The measurement of the ¹³ C-NMR spectrum showed that this polymer had an extremely high syndiotacticity, similarly to the polymer of Example 1.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a process for preparing a polymerization catalyst used in the method of the present invention. FIG. 2 is an NMR spectrum of the polymer obtained in the example.

Claims (1)

(57) [Claims] 1. A Upon mainly producing styrenic polymers having a stereoregularity of syndiotactic structure, as a polymerization _{catalyst, Ti (SO 4) 3 ·} 8H 2 O and Ti (SO _{4) 2} ·
Preparation of styrenic polymer, characterized by using the reaction product of at least one and (CH _{3) 3} Al selected from 4H ₂ O.