JPS62277411A - Polymerization of styrene - Google Patents

Abstract

PURPOSE:To produce polystyrene in high yield per unit volume, by reacting styrene by a specific method in the presence of a catalyst obtained by combining an organic Al compound and a solid catalyst produced by supporting a titanium halide on a magnesium halide. CONSTITUTION:Styrene is polymerized in an aliphatic or alicyclic hydroarbon solvent (e.g. hexane) at a styrene concentration of <=20vol% preferably at room temperature - 60 deg.C in the presence of a catalyst consisting of an organic Al compound and a solid catalyst produced by supporting a titanium halide on a magnesium halide. The polymerization of styrene is continued at a higher styrene concentration and higher temperature than those of the former polymerization process, preferably at a styrene concentration of 15-16vol% and a polymerization temperature of 50-100 deg.C. The organic Al compound used as a component of the catalyst is preferably tripropylaluminum, etc.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for polymerizing styrene. Specifically, it relates to a method for polymerizing styrene using a specific catalyst and in a specific manner.

[Conventional technology]

Methods for polymerizing styrene using Ziegler-Nanta catalysts are already well known (e.g. Macromolecular Synthesis).
Lhesis) supra, 1 (1963)).

In conventional methods using styrene itself or aromatic hydrocarbon solvents, the viscosity of the polymerization solution increases as the conversion rate of styrene increases, making it difficult not only to stir but also to remove the heat of polymerization. Therefore, polymerization has been stopped under conditions where the polystyrene concentration is relatively low.

[Problem that the invention seeks to solve]

To stop polymerization under conditions of low polystyrene concentration, it is necessary to use a relatively large amount of solvent or to stop the reaction when the conversion rate of styrene is low.Industrially, solvents, styrene j! In addition to problems such as recovery of polymers, there were other problems such as the need for a large amount of poor solvent to separate polystyrene. A possible solution to these problems is to carry out slurry polymerization using a poor solvent for polystyrene as a medium, but simply changing the solvent will not only significantly reduce the yield of polystyrene as a catalyst, but also Since the bulk specific gravity of polystyrene is small, there was a problem in that it was not possible to raise the slurry to 21 degrees.

[Means for solving problems]

The present inventors have diligently studied methods for solving the above-mentioned problems, found that the above-mentioned problems can be solved by a specific method, and have completed the present invention.

That is, the present invention uses a solid catalyst obtained by supporting titanium halide on magnesium halide and a catalyst consisting of an organoaluminum compound. This is a styrene polymerization method characterized by polymerizing styrene at a higher styrene concentration and at a higher temperature after polymerizing styrene.

In the present invention, styrene includes styrene and its nuclear substituted styrene, and in addition to styrene, methylstyrene, ethylstyrene, propylstyrene, isomers of butylstyrene, dimethylstyrene, diethylstyrene, dipropylstyrene, and dibutylstyrene are used as styrene. Examples include isomers.

Various types of solid catalysts obtained by supporting titanium halide on magnesium halide used in the present invention are already known, and those used for stereoregular polymerization of α-olefins such as propylene can be used. , for example, Journal of Macromolecular Science Review in Macromolecular Chemistry
acromolecular Science Rev
iews in Macromolecular
Chemistry and Physics)C24
(3), 355-385 (1984), same stop.

57-95 (1985). Specifically, there are two methods: ■ A method of co-pulverizing magnesium halide and titanium halide together with an oxygen-containing organic compound as necessary;
A method of contact-treating titanium halide after co-pulverizing or contact-treating magnesium halide and an oxygen-containing organic compound; A hydrocarbon solvent can be obtained by treating a complexed magnesium halide (or alkoxymagnenoum, etc.) with a halogenating agent (halogenated hydrocarbon, metal halide, etc.) in the presence or absence of an oxygen-containing organic compound. Examples include a method in which the titanium halide is insolubilized and then brought into contact with a titanium halide.

In the present invention, as the fi aluminum compound, trialkylaluminium, dialkylaluminum halide, or a mixture thereof can be preferably used, and trialkylaluminum such as trimethylaluminum, triethylaluminum, tripropylaluminum, tributylaluminum, trihexylaluminum, etc., especially tripropylaluminum , tributylaluminum is preferably used. There is no particular restriction on the ratio of organoaluminum compound to titanium halide, but it is 1 to 1000.
0 molar ratio is usually 10 to 1000 molar ratio.

In the present invention, aliphatic hydrocarbons or alicyclic hydrocarbons are used as the polymerization medium, and specific examples include fukune, pentane, hexane, cyclohexane, methylcyclohexane, heptane, nonane, decane, and mixtures thereof.

What is important in this invention is that the styrene concentration is 20V at the beginning.
The purpose is to polymerize styrene under conditions where olX or less. When the styrene concentration is higher than 20 VolX, the bulk specific gravity of the polystyrene obtained is small and the activity of the catalyst is poor. The preferred concentration range of styrene is 0. I
Volχ~20Volχ, particularly preferably 1~15V
It is olχ. The polymerization temperature here is 0°C to 70°C.
, preferably room temperature to 60°C. There is no particular limit to the time for this initial polymerization, but 0.00% per 1g of solid catalyst.
It is preferable to carry out the reaction for a period of time until 0.1 g or more of styrene is polymerized.

In the present invention, the styrene concentration is then further increased and the polymerization reaction is carried out at a higher temperature. The styrene concentration at this time is 10 to 80 Volχ, preferably 15 to 60 V.
The polymerization temperature is from room temperature to 130°C, preferably from 50 to 100°C. Here, the polymerization time may be arbitrarily determined so as to obtain a desired styrene conversion rate.

During the above polymerization reaction, it is also possible to add a molecular weight regulator such as hydrogen, and the organoaluminum compound can also be used in portions.

After the polymerization reaction, the catalyst is deactivated with alcohol or the like, and then treated with water or the like to deash, and then the polystyrene can be separated by filtering and washing the car.

〔Example〕

The present invention will be further explained below with reference to Examples.

Example 1 Magnesium chloride 20g, tetraethoxysilane 3II
A co-pulverized product obtained by co-pulverizing 11 and 4 ml of α, α, α-trichlorotoluene for 40 hours was contacted with 200 ml of titanium tetrachloride at 80°C for 2 hours, and then the solid was washed with n-heptane. A solid transition metal catalyst supporting halogen titanium such as magnesium chloride was obtained.

500+++ g of this solid transition metal catalyst and 1.6 ml of triisobutylaluminum were placed in a 300 ml round bottom flask, 100 ml of n-hebutane and 10 ml of styrene were added, and the mixture was stirred at 50°C for 30 minutes. When a portion was taken out, 1.2 g of styrene had been polymerized.

Put 900 ml of n-hebutane and 590 ml of styrene into a No. 31 autoclave, add the above polystyrene slurry and triisobutylaluminum 41111, and add 0.5 kg/c+ of hydrogen! was added and polymerized at 70°C for 1 hour.

Next, 10 ml of methanol was added to deactivate the catalyst, the temperature was lowered, the mixture was filtered and dried, and weighed to obtain 155 g of polystyrene. The weight average molecular weight was 1.5 x 10', the melting point was 223°C, and the bulk specific gravity was 0.26 g/tt.

Comparative Example 1 Catalyst components, 600 ml of styrene and 10,100 O of n-hebutane were placed in an autoclave from the beginning without pretreatment in a flask, and polymerization was carried out. The amount of polystyrene taken out after 1 hour was 104 g, and the weight average molecular weight was 3.
．． lX10', bulk specific gravity is 0.19g#! Met.

Example 2 Pretreatment with 100 ml of n-hebutane. Polymerization was carried out at 50°C using 5 ml of styrene and 5 ml of tripropyl aluminum, and 900 n+l of hebutane and 595 ml of styrene were added for polymerization in an autoclave at 70°C for 1 hour.

The obtained polystyrene weighed 140 g, had a weight average molecular weight of 1.6 x 10', and a bulk specific gravity of 0.24 g/1.

Furthermore, it is solid when processed! 0.214% per gram of metal catalyst.
3g of styrene had been polymerized.

Example 3 The same procedure as in Example 1 was carried out except that the pretreatment was carried out using styrene 201 at 40°C. The obtained polymer weighed 175 g, had a weight average molecular weight of 1.8 x 10', and a bulk specific gravity of 0.2.
8g/7! , the melting point was 225°C. The amount of styrene polymerized in the pre-treatment was 0.9g vs. solid i! ! The amount of transfer metal catalyst was 1 g.

〔Effect of the invention〕

By employing the method of the present invention, polystyrene can be obtained with a good yield per catalyst, a relatively high conversion rate, and a high yield per reaction volume, and is extremely valuable industrially.

[Brief explanation of drawings]

FIG. 1 is a flowchart to aid in understanding the polymerization method of the present invention.

Claims (1)

[Claims] 1. Using a solid catalyst obtained by supporting titanium halide on magnesium halide and a catalyst consisting of an organoaluminum compound, a styrene concentration of 20 vol% or less is used in an aliphatic or alicyclic hydrocarbon solvent. A method for polymerizing styrene, which comprises polymerizing styrene and then polymerizing styrene at a higher styrene concentration and at a higher temperature. 2. A method for polymerizing styrene according to claim 1, in which the polymerization is carried out at a styrene concentration of 20 Vol% or less until 0.01 g or more of styrene is polymerized per 1 g of solid catalyst. The method for polymerizing styrene according to claims 1 and 2, wherein the polymerization is carried out at 60°C.