JP2796972B2 - Preparation of stereoregular aromatic vinyl polymer - Google Patents

Description

The present invention relates to a method for producing a stereoregular aromatic vinyl polymer.

More specifically, the present invention relates to a method for producing a polymer of an aromatic vinyl compound having a syndiotactic structure by using a catalyst comprising an organic titanium compound obtained by reacting a titanium compound with an organic compound and alumoxane. It is.

[Conventional technology]

Aromatic vinyl polymers, especially polystyrene, can be produced by various polymerization methods such as radical polymerization, anionic polymerization and cationic polymerization.

Polystyrene produced by radical polymerization using an initiator that generates free radicals and thermally generating radicals is amorphous and has a temperature of about 100 ° C.
Has a glass transition temperature, and at a temperature higher than this, it has no practical properties as a molded article or the like.

Polystyrene obtained by a conventional anionic polymerization method using an initiator such as butyllithium or a cationic polymerization method using aluminum chloride or tin tetrachloride is also amorphous.

Polystyrene obtained by coordinating anionic polymerization using a Ziegler-Natta type catalyst such as a titanium trichloride / triethylaluminum compound system has mainly isotactic stereoregularity and a melting point of about 220.
° C, but its crystallization rate is very slow, and it has not been commercialized.

Here, polystyrene having mainly syndiotactic stereoregularity was first announced by Ishihara et al. At the annual polymer meeting in May 1986. It has been reported that not only the melting point is as high as 260 ° C. or higher, but also that the crystallization rate is much faster than that of isotactic polystyrene. As a catalyst for synthesizing such syndiotactic polystyrene, a catalyst system using a combination of a titanium compound such as titanium tetrachloride or tetraethoxytitanium and an organoaluminum compound such as methylalumoxane is disclosed in -187708 and JP-A-62-104818. Further, a catalyst system comprising a transition metal compound such as titanium tetrachloride, an organic compound having at least two hydroxyl groups, and alumoxane is described in JP-A-63-191811.

[Problems to be solved by the invention]

However, since the activity of the polymerization of a styrene monomer in a catalyst system using a combination of a titanium compound such as titanium tetrachloride or tetraethoxy titanium and methylalumoxane is low, there are many catalyst residues remaining in the produced polymer,
The degree of thermal coloring during heat molding is expected to be large and is not practical.

In a catalyst system comprising methyl alumoxane and a complex obtained by reacting a transition metal compound such as titanium tetrachloride with a diphenyl sulfide-based organic compound, although the polymerization activity is considerably high, mainly an atactic polymer is used. By-products result in a slightly lower proportion of highly stereoregular polymer in the total polymer produced. If the amount of the amorphous polymer increases, it affects the melting point and crystallization rate of the polymer.
There is a problem that a post-treatment such as solvent extraction is required.

[Means for solving the problem]

Accordingly, the present inventors have conducted extensive research and have found that by using a catalyst system comprising an organic titanium compound and a specific organic aluminum compound obtained by reacting a specific titanium compound and an organic compound, a highly active and The present inventors have found that a stereoregular styrene or styrene derivative polymer having nervousness can be efficiently obtained, and have completed the present invention.

That is, the present invention relates to a method for producing a polymer of styrene or a styrene derivative having a syndiotactic structure, wherein (A) a compound represented by the general formula: TiR ¹ (OR ² ) _a X _b (wherein, R ¹ is a cyclopentadiniel group) Or a substituted cyclopentadienyl group, R ² is an alkyl group or an aryl group having 1 to 18 carbon atoms, X represents halogen, a and b are a ≧ 0, b
≧ 0, a + b = 3. ) And a titanium compound represented by (Wherein R ³ , R ⁴ , and R ⁵ represent a hydrocarbon group having 1 to 18 carbon atoms, and R ⁶ , R
⁷ represents a divalent hydrocarbon group having 1 to 8 carbon atoms, and R ⁸ represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. d,
e represents 0 or an integer of 1 to 4; An organic titanium compound obtained by reacting with an organic compound represented by (Wherein, R represents a hydrocarbon group having 1 to 4 carbon atoms, and n represents 1 to 4)
Represents the number 40. ) Wherein the catalyst comprises at least one of alumoxanes.

 Hereinafter, the contents of the present invention will be described in detail.

In the present invention, in the titanium compound represented by the general formula TiR ¹ (OR ² ) _a X _b , R ¹ is a cyclopentadienyl group or a substituted cyclopentadienyl group. For example, cyclopentadienyl, methylcyclopentadiethyl, 1,2-dimethylcyclopentadienyl, pentamethylcyclopentadienyl and the like can be mentioned, and cyclopentadienyl is particularly preferred.

R ² is a hydrocarbon group having 1 to 18 carbon atoms, particularly 2 carbon atoms.
Preferred are alkyl groups having -18 and aryl groups having 6-18 carbon atoms. For example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-butyl
Hexyl, n-octyl, chain alkyl groups such as n-dodecyl, cyclic alkyl groups such as cyclohexyl, phenyl,
And an aryl group such as naphthyl.
-Propyl, isopropyl, n-butyl, isobutyl,
T-butyl, phenyl and the like are preferred.

X represents a halogen atom, and examples thereof include chlorine, bromine and iodine, and chlorine is particularly preferable.

Specific examples of such a titanium compound include cyclopentadienyl titanium trichloride, cyclopentadienyl titanium triethoxide, methylcyclopentadienyl titanium trichloride and the like, and cyclopentadienyl titanium trichloride is particularly preferably used. Can be

In the organic compound represented by R ³ , R ⁴ , R ⁵ has 1 to 1 carbon atoms
A hydrocarbon group having 18 carbon atoms, particularly an alkyl group having 2 to 18 carbon atoms and an aryl group having 6 to 18 carbon atoms are preferable. For example, methyl, ethyl, n-propyl, isopropyl, n
-Butyl, isobutyl, t-butyl, n-hexyl, n
-Octyl, a chain alkyl group such as n-dodecyl, a cyclic alkyl group such as cyclohexyl, an aryl group such as phenyl, naphthyl, and the like.Especially, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl , Phenyl and the like.

R ⁶ and R ⁷ are a divalent hydrocarbon group having 1 to 8 carbon atoms, particularly preferably an alkylene group having 2 to 6 carbon atoms. For example,
Ethylene, propylene, isopropylene, butylene, hexylene and the like are mentioned, and ethylene, propylene and isopropylene are particularly preferable.

R ⁸ is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and includes a hydrogen atom, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-hexyl, and the like. A hydrogen atom and methyl are preferably used. Specific examples of such organic compounds include di (2-hydroxyphenyl) ethylphosphine and di (2
-Hydroxyphenyl) phenylphosphine, di (2-
Methoxyphenyl) phenylphosphine, diethoxyphenylphosphine, diisopropoxyphenylphosphine and the like, and particularly di (2-hydroxyphenyl) phenylphosphine, di (2-methoxyphenyl) Phenylphosphine is preferably used.

The reaction between the titanium compound and the organic compound is, for example, 0 to 150 ° C.
Can be carried out in a hydrocarbon solvent such as toluene or n-hexane or in a polar solvent such as butyl ether.

There is no particular limitation on the molar ratio at the time of the reaction between the titanium compound and the organic compound, and the reaction can be carried out at 0.1 to 10, particularly preferably at an equimolar ratio.

Here, in the reaction between the titanium compound and the organic compound, when R ^{8 in} the general formula of the organic compound is a hydrogen atom, it is bonded to OR ² or X in the general formula of the titanium compound to form an alcohol (HOR ² ) or a halogen, respectively. Hydrogen (HX) is desorbed,
As a result, it is presumed that a titanium complex containing two Ti—O—C bonds is formed. Further, when R ^{8 in} the general formula of the organic compound is a hydrocarbon group, it is bonded to X in the general formula of the titanium compound to release a halogenated hydrocarbon (R ³ X), and as a result, two Ti- It is presumed that a titanium complex containing an OC bond is formed.

The alcohol (HOR ² ), hydrogen halide (HX) or halogenated hydrocarbon (R ³ X) by-produced may be removed from the reaction system by blowing in an inert gas or the like. (HX) may be removed by adding ammonia or the like to cause precipitation.

The alumoxane (B) represented by the formula (1) may be either a chain-like one such as the former or a cyclic one such as the latter,
Further, they may be used in combination.

Here, R represents a hydrocarbon group having 1 to 4 carbon atoms, for example, methyl, ethyl, n-propyl, isopropyl, n
-Butyl, isobutyl, t-butyl and the like, with methyl being particularly preferred. N represents a number of 1 to 40, and particularly preferably 5 or more.

Such an alumoxane is generally obtained by reacting a trialkylaluminum with water, but the method is not particularly limited, and a known method can be used. For example, a method in which a trialkylaluminum is dissolved in a hydrocarbon solvent and gradually brought into contact with an equivalent amount of water, or copper sulfate hydrate or aluminum sulfate hydrate is suspended in the hydrocarbon solvent, and A method in which trialkylaluminum is mildly hydrolyzed using twice as much crystallization water, and the like.

Describing the amount of each catalyst component used, the organic titanium compound obtained by reacting the titanium compound with the organic compound is preferably 10 ^-7 to 10 ³ mmol /, particularly preferably 10 ^-5 to 10 ² as a titanium atom. mmol / is used. The alumoxane (B) is used in a molar ratio of aluminum atom / titanium atom of preferably 1 to 10 ⁵ , particularly preferably 1 to 10 ⁴ . Furthermore, trimethyl aluminum, mu,
General aluminum compounds such as triethylaluminum and diethylaluminum chloride can be used in combination with alumoxane.

The aromatic vinyl compound used in the production of the stereoregular aromatic vinyl polymer in the present invention includes styrene,
o-methylstyrene, m-methylstyrene, p-methylstyrene, o-chlorostyrene, p-chlorostyrene,
α-Methylstyrene and the like can be mentioned, and styrene is particularly preferable. These can be used in homopolymerization or copolymerization of two or more.

The polymerization method using the catalyst system of the present invention is not particularly limited, and ordinary methods such as slurry polymerization and solution polymerization under normal pressure or under pressure can be used. The polymerization process may be a batch type or a continuous type.

As the solvent, an aliphatic hydrocarbon solvent such as n-pentane, n-hexane and isobutane, an alicyclic hydrocarbon solvent such as cyclohexane and methylcyclohexane, or an aromatic hydrocarbon solvent such as benzene and toluene alone or two or more kinds Can be used in combination. Further, it is also possible to carry out the polymerization without using another solvent by using an aromatic vinyl compound as a solvent as a solvent.

The polymerization temperature is preferably from 0 to 150 ° C., particularly preferably from 20 to 150 ° C.
Can be performed at ~ 90 ° C.

〔Example〕

Hereinafter, the effects of the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

In the examples, the methyl ethyl ketone (MEK) insoluble portion (%) is defined as a percentage of the weight of the produced polymer boiling MEK insoluble portion with respect to the weight of the entire produced polymer.

The stereoregularity of the resulting polymer was determined by ¹³ C-NMR analysis by assigning the signal of the aromatic ring C1 carbon. Attribution is made by Makromolecular Che
mie) 176 3051 (1975). The measurement was performed by dissolving the polymer in o-dichlorobenzene and using a magnetic resonance spectrometer FX90Q manufactured by JEOL at 135 ° C.

Example 1 (1) Synthesis of organic titanium compound (I) Di (2-methoxyphenyl) used as an organic compound
Phenylphosphine was reported by AESenear et al. [Journal of Organic Chemistry (Jo
urnal of Organic Chemistry) 25 2001 (1960)] with reference to o-bromoanisole.
rd) It was synthesized by reacting with dichlorophenylphosphine as a reagent.

2.0 mmol of this compound was dissolved in 50 ml of toluene and placed in a 200 ml flask equipped with a stirrer purged with nitrogen, and cyclopentadienyl titanium trichloride 2.
0 mmol was dissolved in 25 ml of toluene and added dropwise over 2 hours. Stirring was further continued for 2 hours, and the reaction solution was added to n-hexane to produce a yellow-orange precipitate, which was separated by filtration, washed and dried.
The obtained yellow-orange solid was dissolved in toluene and used as a 5 mmol / solution.

(2) Synthesis of alumoxane The synthesis was carried out as follows in accordance with Example 1 of JP-A-58-19309. All operations were performed under a nitrogen atmosphere. CuSO ₄ · 5H ₂ O37.5g a (0.15 mol) was suspended in toluene 250 ml, was added trimethylaluminum 50 ml (0.52 mol) Oyutsukuri was continued for 24 hours pay under stirring 20 ° C.. At this time, generation of methane gas was recognized. After the reaction, copper sulfate is filtered off, toluene is removed from the filtrate, and methylalumoxane is removed.
13.0 g was obtained as a white solid. The molecular weight measured by the freezing point depression method of benzene was 640, and the average degree of oligomerization was 11.

(3) Polymerization of Styrene 25 ml of toluene, 5 mmol of methylalumoxane and 0.025 mmol of organic titanium compound (I) were placed in a 100-ml glass pressure-resistant bottle purged with nitrogen. Next, 25 ml of styrene was added and polymerization was carried out at 60 ° C. for 1 hour with stirring. Thereafter, the content was poured into hydrochloric acid-metallur to terminate the reaction, and the precipitated polymer was separated by filtration and dried. The resulting polymer weight is
2.54 g, and the MEK-insoluble portion of the polymer was 99%. This means that 2.12 kg of MEK-insoluble polymer was produced per hour per 1 g of titanium atom. The stereoregularity of the polymer in the insoluble portion was confirmed by ¹³ C-NMR analysis to have an almost 100% syndiotactic structure. (See FIG. 1.) On the other hand, it was confirmed by ¹³ C-NMR analysis that the MEK-soluble polymer was an atactic polymer. (See FIG. 2) Comparative Example 1 2,2'-dihydroxy-3,3'-di-t-butyl-5,5'-dimethyl described in JP-A-62-191811 as an organotitanium compound Polymerization was carried out in the same manner as in Example 1 except that a black-brown solid (A) which was a reaction product of diphenylsulfide and titanium tetrachloride was used. As a result, the weight of the produced polymer was 1.52 g. 89% of MEK insolubles
It was. Therefore, 1.13 kg of ME per hour per gram of titanium atom
This means that the K-insoluble polymer was formed. At this time, it was confirmed by ¹³ C-NMR analysis that the polymer soluble in the MEK was also an atactic polymer.

That is, this catalyst system was inferior to Example 1 in both the polymerization activity and the MEK insoluble part%.

Comparative Example 2 The polymerization was carried out in the same manner as in Example 1 except that tetraethoxytitanium was used as the organic titanium compound and the polymerization time was set to 2 hours.
2.80 g, and the MEK-insoluble portion of the polymer was 93%. This means that 1.09 kg of MEK-insoluble polymer was produced per hour per 1 g of titanium atom.

That is, this catalyst system was inferior to Example 1 in both the polymerization activity and the MEK insoluble part%.

Example 2 The polymerization was carried out in the same manner as in Example 1 except that 10 ml of toluene and 40 ml of styrene were used.
7.75 g, and the MEK-insoluble portion of the polymer was 98%. This means that 6.34 kg of the MEK-insoluble polymer was produced per hour per 1 g of titanium atom.

Comparative Example 3 2,2'-dihydroxy-3,3'-di-tert-butyl-5,5'-dimethyldiphenylsulfide described in JP-A-62-191811 as an organotitanium complex Polymerization was carried out in the same manner as in Example 2 except that a black-brown solid which was a reaction product with titanium tetrachloride was used, and the polymerization time was set to 20 minutes. As a result, the weight of the produced polymer was 1.87 g, The MEK insoluble portion of this polymer was 94%. This means that 4.43 kg of MEK-insoluble polymer was produced per hour per 1 g of titanium atom.

That is, this catalyst system is inferior to Example 2 in both the polymerization activity and the MEK insoluble part%.

Comparative Example 4 Polymerization was carried out in the same manner as in Example 2 except that cyclopentadienyltitanium trichloride was used as the organic titanium compound (B) instead of the organic titanium compound (I). As a result, the weight of the produced polymer was 3.85. g and M of this polymer
The EK insoluble portion was 90%. This means that 2.92 kg of the MEK-insoluble polymer was produced per hour per 1 g of titanium atom.

That is, this catalyst system is inferior to Example 2 in both the polymerization activity and the MEK insoluble part%.

Example 3 (1) Synthesis of organic titanium compound (II) Di (2-hydroxyphenyl) phenylphosphine used as an organic compound was di (2-methoxyphenyl)
Phenylphosphine was obtained by treatment in boiling hydrobromic acid followed by aqueous sodium hydroxide. Dissolve 1.0 mmol of this compound in 50 ml of toluene, place in a 200 ml flask equipped with a stirrer purged with nitrogen, dissolve 1.0 mmol of cyclopentadienyltitanium trichloride in 25 ml of toluene with sufficient stirring at 60 ° C., and heat the solution for 3 hours. It was dropped. Stirring was further continued for 1 hour, and the reaction solution was added to n-hexane to produce a yellow-orange precipitate, which was separated by filtration, washed and dried. The obtained yellow-orange solid was dissolved in toluene and used as a 10 mmol / solution.

(2) Polymerization of styrene The polymerization was carried out in the same manner as in Example 1 except that the organotitanium compound (II) was used. As a result, the weight of the produced polymer was 2.32 g, and the MEK-insoluble portion of this polymer was 97%. Was. This means that 1.88 kg of MEK-insoluble polymer was produced per hour per 1 g of titanium atom.

 The above Examples and Comparative Examples are shown in Table 1.

〔The invention's effect〕

By polymerizing an aromatic vinyl compound using the catalyst system of the present invention, a stereoregular styrene or styrene derivative polymer having a high degree of syndiotacticity can be efficiently produced. MEK in the resulting polymer
Since the insoluble portion% is extremely high, a polymer having high stereoregularity can be obtained without any post-treatment such as extraction, and the significance in the production technology is great.

[Brief description of the drawings]

FIG. 1 shows the MEK of the polystyrene obtained in Example 1.
FIG. 2 shows the MEK fusible portion of the first embodiment.
It is a spectrum of aromatic ring Cl carbon in ¹³ C-NMR. The signal in FIG. 1 is assigned to the [rrrr] pentad, indicating that the insoluble polymer has nearly 100% syndiotactic stereoregularity. On the other hand, in FIG. 2, many signals corresponding to each sequence are detected.
This shows the characteristics of the attack polymer. FIG. 3 is a schematic flow sheet showing an embodiment of the present invention.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C08F 4/60-4/70

Claims (1)

(57) [Claims] 1. A compound of the general formula TiR ¹ (OR ² ) _a X _{b wherein} R ¹ is a cyclopentadienyl group or a substituted cyclopentadienyl group, and R ² is an alkyl or aryl group having 1 to 18 carbon atoms. , X represents halogen, a and b are a ≧ 0, b
≧ 0, a + b = 3. ) And a titanium compound represented by (Wherein, R ³ , R ⁴ and R ⁵ represent a hydrocarbon group having 1 to 18 carbon atoms, and R ⁶ , R ⁷
Represents a divalent hydrocarbon group having 1 to 8 carbon atoms, and R ⁸ represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, respectively. d, e
Represents 0 or an integer of 1 to 4. An organic titanium compound obtained by reacting with an organic compound represented by (Wherein, R represents a hydrocarbon group having 1 to 4 carbon atoms, and n represents 1
Represents the number of ~ 40. A method for producing a polymer of styrene or a styrene derivative having a syndiotactic structure, characterized by using a catalyst comprising at least one alumoxane represented by the following formula: