JPH01240502A - Method for producing styrenic polymers and their catalysts - Google Patents

Abstract

PURPOSE:To efficiently produce a styrene-based polymer with a high syndiotacticity with an economical advantage, by using a catalyst consisting of a Ti compound and a product prepared by contacting a specified organoaluminum compound with water. CONSTITUTION:Styrene and/or a styrene derivative is polymerized using a catalyst consisting (A) a Ti compound (e.g., methyltitanium trichloride, TiBr4 or cyclopentadienyltitanium dichloride) and (B) a product prepared by contacting trimethyl aluminum and a tribranched alkyl aluminum (e.g., triisobutyl alumi num) of the formula AlR3 (R is 3-10C branched alkyl) with water to provide the objective polymer preferably composed of a syndiotactic structure as the main structure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a styrenic polymer and a catalyst used in the method. The present invention relates to a method for efficiently producing a styrenic polymer and a catalyst used in the method.

[Problems to be solved by conventional techniques and inventions] Conventionally,
It is known that a catalyst consisting of a contact product of water with (A) a titanium compound and (B) an organoaluminum compound is used to polymerize styrene or styrene derivatives to produce a styrenic polymer having a syndiotactic structure. (Japanese Unexamined Patent Publication No. 187708/1983).

In the above catalyst, a contact product of trimethylaluminum and water is used as the component (B), but since trimethylaluminum as a raw material is expensive, the catalyst cost is extremely high. However, when part of this trimethylaluminum is replaced with other linear alkylaluminum, there is a problem in that the polymerization activity decreases.

Therefore, the present inventors have conducted extensive research in order to develop a method for more efficiently producing a styrenic polymer mainly having a syndiotactic structure, as well as an inexpensive and highly active polymerization catalyst.

[Means to solve the problem]

As a result, it has been found that the above problems can be solved by using trimethylaluminum in combination with a specific organic aluminum compound as a raw material for component (B). The present invention was completed based on this knowledge.

That is, the present invention provides a catalyst for producing a styrenic polymer comprising (A) a titanium compound and (B) a contact product of an organoaluminum compound and water. As a contact product, trimethylaluminum and the general formula % formula % [wherein R represents a branched alkyl group having 3 to 10 carbon atoms] are used.

] The present invention provides a catalyst for producing a styrenic polymer, which is characterized by using a contact product of a tribranched alkyl aluminum represented by the following formula and water.

The catalyst of the present invention has the above-mentioned components (A) and (B) as main components, and there are various kinds of titanium compounds as component (A). For example, the general formula % formula % () [wherein R1, Rz, R:l and R4 are each a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a carbon number 6 to 20 Okay-ru group.

Alkylaryl group, arylalkyl group, carbon number 1-
20 acyloxy group, cyclopentagenyl i, i-substituted cyclopentagenyl group, indenyl group, or 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 the following.

R1, RZ, R3 in this general formula (I) or (II)
and R4 are each a hydrogen atom or an alkyl group having 1 to 20 carbon atoms (specifically, a methyl group, an ethyl group, a propyl group, a butyl group, an amyl group, an isoamyl group).

isobutyl group, octyl group, 2-ethylhexyl group), alkoxy groups 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.).

Aryl groups, alkylaryl groups, and arylalkyl groups having 6 to 20 carbon atoms (specifically, phenyl groups).

[・Ryl group, xylyl group, benzyl group, etc.), carbon number 1
~20 acyloxy groups (specifically heptadecylcarbonyloxy groups, etc.), cyclopentadienyl groups, substituted cyclopentadienyl groups (specifically methylcyclopentadienyl groups 1 t, 2-dimethylcyclopentadienyl groups) group, pentamethylcyclopentagenyl group, etc.),
Indicates an indenyl group or a halogen atom (chlorine, bromine, iodine, fluorine). These R', RZ, R3 and R4 may be the same or different. Further, a, b, and c each represent an integer of 0 to 4, and d,
e each represents an integer of 0 to 3.

Specific examples of the tetravalent titanium compound and titanium chelate compound represented by the general formula (1) include methyltitanium trichloride, titanium tetramethoxide, titanium tetraethoxide, titanium monoisopropoxy trichloride, and titanium diisopropoxytrichloride. Propoxy dichloride, titanium triisoproboxy monoquala ide, tetra(2-ethylhexyloxy) titanium, cyclopentadienyl titanium trichloride, biscyclopentajenyl titanium dichloride, cyclopentadienyl titanium trimethoxide,
Cyclopentadienyltrimethyltitanium, pentamethylcyclopentadienyltitanium trimethoxide, pentamethylcyclopentadienyltrimethyltitanium, titanium tetrachloride, titanium tetrabromide, bis(2,4-pentanedionato)titanium oxide, bis( Examples include 2°4-pentanedionato) titanium dichloride and bis(2,4-pentanedionato) titanium dibutogide. In addition to the above-mentioned titanium compounds as component (A), the general formula [wherein R5 and R6 are each a halogen atom and carbon number 1]
~20 alkoxy group, acyloxy group, k is 2~
20 is shown. ] You may use the condensed titanium compound represented by these.

Furthermore, the titanium compound may be a complex formed with an ester, an ether, or the like.

The trivalent titanium compound represented by the general formula (U), which is another type of component (A), is typically a titanium trihalide such as titanium trichloride, or a cyclopentadienyl titanium compound such as cyclopentadienyl titanium dichloride. Examples include titanium compounds, and those obtained by reducing tetravalent titanium compounds. These trivalent titanium compounds may be complexed with esters, ethers, etc.

On the other hand, as the component (B) which constitutes the main component of the catalyst together with the titanium compound component (A), trimethylaluminum and the general formula % formula % () [wherein R is a carbon number of 3 to 10] are used. Indicates a branched alkyl group.

] A contact product of tribranched alkyl aluminum and water is used. In the above general formula (IV),
R is a branched alkyl group having 3 to 10 carbon atoms, such as isopropyl group 9, isobutyl a, 5ee-butyl%, te
rt-butyl group, isopentyl group, neopentyl group, 2
- methylpentyl group, 2-methylhexyl group, 2-ethylhexyl group, etc., and the tribranched alkylaluminum represented by the general formula (IV) is specifically triisopropylaluminum, triisobutylaluminum, tritert-butylaluminum , triisopentylaluminum, tri(2-methylpentyl)aluminum, tri(2-methylhexyl)aluminum.

Examples include tri(2-ethylhexyl)aluminum, among which triisobutylaluminum is preferred.

In preparing the contact product which is component (B), trimethylaluminum and the tribranched alkyl aluminum represented by the general formula (IV) can be used in various ratios; ;99.9:0.1~50:50(
molar ratio), preferably 98:2 to 75:25 (molar ratio)
Use in combination at a ratio of If the proportion of the tribranched alkyl aluminum is too large, the resulting contact product with water will become insoluble in the hydrocarbon solvent that is the polymerization solvent, and sufficient activity will not be expressed. On the other hand, if the proportion of tribranched alkylaluminum is small, the amount of trimethylaluminum used becomes large, which is economically disadvantageous, and at the same time, the improvement in activity becomes insufficient.

Component (B) of the catalyst of the present invention is a contact product of trimethylaluminum and tribranched alkylaluminum with water as described above, and water here includes ordinary water,
Ice or various water-containing compounds, such as solvent-saturated water, water adsorbed by inorganic substances, or crystal water containing metal salts such as Cu5O, .5H, O, etc., can be used.

The contact product of trimethylaluminum and tribranched alkyl aluminum with water can be prepared by various methods. (2) a method in which trimethylaluminum and tribranched alkylaluminum are initially added during polymerization, and then water is added;
There are methods such as reacting water of crystallization contained in metal salts and water adsorbed to inorganic or organic substances with trimethylaluminum and tribranched alkylaluminum.

The catalyst of the present invention has the above-mentioned components (A) and (B) as main components, and in addition to the above-mentioned components, if desired, other catalyst components, such as general AlR73 [wherein R7 has 1 carbon number]
~8 alkyl group is shown. ] Trialkylaluminum or other organometallic compounds can also be added. When using this catalyst, the (
The ratio of component A) to component (B) varies depending on various conditions and cannot be unambiguously determined, but it is usually determined by the ratio of aluminum in component (B) to titanium in component (A), that is, aluminum/ The titanium (mole ratio) is 1 to 106, preferably 10 to 10'.

The catalyst of the present invention as described above exhibits high activity mainly in the production of styrenic polymers 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 styrenic monomers such as styrene and/or styrene derivatives (alkyl styrene, alkoxystyrene, halogenated styrene, vinyl benzoate, etc.) in the presence of a catalyst containing the components (A) and (B) as main components. (or copolymerization), but this polymerization may be in bulk,
The reaction may be carried out in an aliphatic hydrocarbon solvent such as pentane, hexane or heptane, an alicyclic hydrocarbon solvent such as cyclohexane, or an aromatic hydrocarbon solvent such as Hensen, toluene or xylene. In addition, the polymerization temperature is not particularly limited, but generally -
30°C to +120°C1 preferably =10°C to +1
00°C.

Furthermore, in order to control the molecular weight of the obtained styrenic polymer, it is effective to carry out the polymerization reaction in the presence of hydrogen.

The styrenic polymer thus obtained mainly has a syndiotactic structure. here,
A mainly syndiotactic structure in a styrenic polymer means that the stereochemical structure is mainly a syndiotactic structure, that is, the main chain formed from carbon-carbon bonds has alternate phenyl groups or substituted phenyl groups as side chains. It means that it has a three-dimensional structure located in the opposite direction, and its toughness is determined by nuclear magnetic resonance method using carbon isotope ("C-
Quantified by NMR method). 13c Toughness measured by NMR method is determined by the proportion of consecutive constituent units, e.g.
Triat for pieces.

The case of 5 can be represented by a pentad, but
In the present invention, the term "styrenic polymer mainly having a syndiotactic structure" is usually 75% diad.
Polystyrene, poly(alkylstyrene), poly(halogenated styrene) having syndiotacticity of 85% or more, or 30% or more for pentads (racemic pentads), preferably 50% or more
, poly(alkoxystyrene), poly(vinyl benzoate), mixtures thereof, or copolymers containing these as main components. Here, poly(alkylstyrene) includes poly(methylstyrene), poly(methylstyrene), Poly(ethylstyrene), poly(isopropylstyrene),
Examples include poly(tert-butylstyrene), and examples of poly(halogenated styrene) include poly(chlorostyrene), poly(bromostyrene), poly(fluorostyrene), and the like. Furthermore, examples of poly(alkoxystyrene) include poly(methoxystyrene) and poly(ethoxystyrene). Among these, a particularly preferred styrenic polymer is polystyrene.

Poly(p-methylstyrene), poly(m-methylstyrene), poly(p-tert-butylstyrene), poly(p-chlorostyrene), poly(m-chlorostyrene)
, poly(p-fluorostyrene), and copolymers of styrene and p-methylstyrene.

The styrenic polymer produced by the method of the present invention generally has a number average molecular weight of 1,000 to 5,000,000, preferably 50,000 to 4,000,000. After polymerization, it is deashed with a cleaning solution containing hydrochloric acid, etc., if necessary, and then washed and dried under reduced pressure, and then washed with a solvent such as methyl ethyl ketone to remove soluble components. If the resulting insoluble matter is further treated with chloroform or the like, a highly purified styrenic polymer with extremely high syndiotacticity can be obtained.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 (1) Preparation of contact product of aluminum compound and water In a glass container with an internal volume of 500/d and replaced with argon,
Toluene 200%, copper sulfate pentahydrate (CuSO=・5Hz
O) 23.7 g (95 mmol), 21.5 d (225 mmol) of trimethylaluminum, and 6.3 d (25 mmol) of triisobutylaluminum, and 4
The reaction was carried out at 0°C for 24 hours.

After that, the solution obtained by removing the solid component was further heat-treated at 110°C for 2 hours under reduced pressure to form a colorless solid (
6.12 g of contact product) was obtained. Add this to 50t of toluene
It was dissolved in .rll to prepare a catalyst solution.

(2) In a reaction vessel with a styrene polymerization internal volume of 5001 d, 25 ml of heptane, 6 mmol of the contact product obtained in (1) above as aluminum atoms, 12×10 mmol of pentamethylcyclopentadienyl titanium trimethoxide, and Styrene 225Id was added and a polymerization reaction was carried out at 70°C for 3 hours.

After the reaction was completed, the product was washed with a hydrochloric acid-methanol mixture to decompose and remove the catalyst component, and dried to obtain 48.1 g of a polymer. The polymerization activity was 297 g/g-Al. The racemic pentad syndiotacticity of this polymer was found to be 96% by C-NMR measurement.

Examples 2 to 4 and Comparative Examples 1 to 3 (1) Preparation of contact product of aluminum compound and water In Example 1 (1), the amount of trimethylaluminum was changed, and the amount of triisobutylaluminum was 6.3 mj!
A contact product was obtained by carrying out the same operation as in Example 1 (1), except that the predetermined amount of aluminum compound shown in the table was used instead of (25 mmol), and this was dissolved in toluene. This was used as a catalyst solution.

(2) Polymerization of styrene A polymer (polystyrene) was obtained in the same manner as in Example 1 (2) except that the catalyst solution obtained in (1) above was used. The results are shown in the table.

(The following is a blank space) [Effects of the Invention] As described above, the catalyst of the present invention is cheaper and has significantly higher activity than a catalyst using only trimethylaluminum as the organoaluminum compound in the contact product with water. It is something. Therefore, if a styrenic monomer is polymerized using this catalyst, a styrenic polymer with high syndiotacticity can be produced economically and efficiently.

The styrenic polymer having a syndiotactic structure thus obtained has excellent physical properties such as heat resistance and chemical resistance, and is widely and effectively used in various applications.

Claims (4)

[Claims] (1) In a catalyst for producing a styrenic polymer comprising (A) a titanium compound and (B) a contact product between an organoaluminum compound and water, the contact product between the organoaluminum compound (B) and water; As, trimethylaluminum and the general formula AlR_3 [wherein, R represents a branched alkyl group having 3 to 10 carbon atoms]. ] A catalyst for producing a styrenic polymer, characterized in that it uses a contact product of a tribranched alkyl aluminum represented by the following formula and water. (2) The catalyst according to claim 1, wherein the tribranched alkyl aluminum is triisobutyl aluminum. (3) A method for producing a styrenic polymer, which comprises using the catalyst according to claim 1 or 2 in polymerizing styrene and/or a styrene derivative. (4) The manufacturing method according to claim 3, wherein the styrenic polymer is a styrenic polymer mainly having a syndiotactic structure.