JPH04366107A - Preparation of syndiotactic polypropylene - Google Patents

Abstract

PURPOSE:To produce highly syndiotactic polypropylene having a desired mol.wt. without decreasing polymerization activity, by using a catalyst comprising a specific transition metal compound and a promoter to polymerize propylene in the presence of an internal olefin. CONSTITUTION:Propylene is polymerized using a catalyst which comprises a transition metal compound of the formula (wherein A<1> and A<2> each is cyclopentadienyl, indenyl, or fluorenyl; A<3> and A<4> each is a 6-20C aryl, a halogenated aryl, a 1-10C alkyl, or H, provided that at least either of A<3> and A<4>b is an aryl or a halogenated aryl; R<1> and R<2>b each is a halogen, H, a 1-10C alkyl, or an aryl; M is Ti, Zr, or Hf; and Q is a compound connecting A<1> to A<2> and containing C, Si, Ge, or Sn) and a promoter in the presence of an internal olefin. Thus, a highly syndiotactic polypropylene having a desired mol.wt. is produced without decreasing polymerization activity.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing syndiotactic polypropylene. Specifically, the present invention relates to a method for producing syndiotactic polypropylene having a desired molecular weight and high tacticity. More specifically, the present invention relates to a method for producing syndiotactic polypropylene having a desired molecular weight and high tacticity without reducing polymerization activity.

0002

[Prior Art] Transition metal compounds, so-called metallocene compounds, having a cyclopentadienyl group, indenyl group, fluorenyl group, or a derivative thereof as a ligand are used together with a cocatalyst such as aluminoxane to polymerize α-olefins. It is known that poly-α-olefins can be produced by this method.

JP-A-58-19309 discloses (cyclopentadienyl) 2 MeRHal (where R is cyclopentadienyl, C1 to C6 alkyl, halogen, Me is a transition metal, A method is described in which ethylene and/or α-olefin are polymerized or copolymerized in the presence of a catalyst consisting of a transition metal compound represented by (Hal is halogen) and aluminoxane.

[0004] JP-A-60-35008 describes that poly-α-olefins having a wide molecular weight distribution can be produced by using a catalyst consisting of at least two metallocene compounds and aluminoxane.

JP-A-61-130314 describes a method for producing polyolefins using a catalyst consisting of a sterically fixed zircon chelate compound and aluminoxane. The publication also describes a method for producing polyolefins with a high degree of isotacticity by using ethylene-bis-(4,5,6,7-tetrahydro-1-indenyl)zirconium dichloride as a transition metal compound. Are listed. JP-A-64-66124 discloses a catalyst for producing stereoregular olefin polymers containing a transition metal compound having a silicon-crosslinked cyclopentadienyl compound as a ligand and aluminoxane as an active ingredient. .

[0006] In JP-A-2-41303, the following formula (Chemical formula 2)

[0007]

[Chemical formula 2]R”(CpRn)(CpR'm)Me
Qk (wherein each Cp is a cyclopentadienyl or substituted cyclopentadienyl ring; each Rn may be the same or different and is a hydrocarbyl residue having 1 to 20 carbon atoms; each R' m may be the same or different and are hydrocarbyl residues having 1 to 20 carbon atoms; R'' is C which provides steric rigidity to the catalyst.
is a structural bridge between the p rings; Me is a metal of group 4b, 5b, or 6b of the periodic table of the elements; each Q is 1 to 20
is a hydrocarbyl residue or halogen having a carbon atom; 0≦k≦3: 0≦n≦4: and 1≦m≦4;
and R'm are selected such that (CpR'm ) is sterically different from (CpRn ). It is described that a poly-α-olefin with good syndiotacticity can be produced by using a catalyst containing as one component.

[0008] The same publication also describes that syndiotactic poly-α-olefins having a wide molecular weight distribution can be produced by using two or more of the above metallocene compounds. In JP-A-2-274703, the following formula (Chemical formula 3)

[0009]

[In the formula, M1 is titanium, zirconium, vanadium, niobium or tantalum, and R1 and R2
may be the same or different from each other, hydrogen atom, halogen atom, alkyl group having 1 to 10 carbon atoms, alkoxy group having 1 to 10 carbon atoms, aryl group having 6 to 20 carbon atoms, 6 carbon atoms -20 aryloxy group, C2-10 alkenyl group, C7-40 arylalkyl group, C7-40 alkylaryl group or C8-40 arylalkenyl group R3 and R4 are different and represent mononuclear or polynuclear hydrocarbon groups capable of forming a sandwich structure together with the central atom M1, and R5 is

0010

[Chemical formula 4] =BR6, =AlR6, -Ge-, -Sn-, -O
-, -S-, =SO, =SO, =NR6, =CO,
=PR6 or =P(O)R6, in which case R
6, R7 and R8 may be the same or different and each represents a hydrogen atom, a halogen atom, or a carbon atom number of 1 to 1.
0 alkyl group, fluoroalkyl group having 1 to 10 carbon atoms, fluoroaryl group having 6 to 10 carbon atoms, aryl group having 6 to 20 carbon atoms, alkoxy group having 1 to 10 carbon atoms, number of carbon atoms Alkenyl group having 2 to 10 carbon atoms, arylalkyl group having 7 to 40 carbon atoms, 8 to 4 carbon atoms
40 arylalkenyl groups or 7 to 40 carbon atoms
or R6 and R7 or R6 and R8 respectively take together with their bonding atoms to form a ring, and M2
is silicon, germanium or tin. A method for producing a high molecular weight syndiotactic polyolefin by polymerizing an olefin in the presence of a catalyst consisting of a transition metal component represented by ] and aluminoxane is described.

Furthermore, JP-A-2-274704 describes a method for producing a high molecular weight syndiotactic polyolefin using a similar hafnium compound. However, these publications contain phenyl (
Only zirconium or hafnium compounds having a methyl)methylene-(9-fluorenyl)(cyclopentadienyl) group or a diphenylmethylene-(9-fluorenyl)(cyclopentadienyl) group as a ligand are described; There is no description at all about the synthesis and physical properties of the transition metal compound containing a halogen atom used in the present invention.

On the other hand, the active species of the so-called Kaminsky type catalyst as described above is [Cp'2MR]+ (where Cp'
= cyclopentadienyl derivative, M = Ti, Zr, H
Since it was suggested that transition metal cations such as those represented by f, R = alkyl), some catalyst systems that do not use aluminoxanes as promoters have been reported.

[0013] Taube et al. Organom
etall. Chem. , 347, C9 (1
988) to [Cp2 TiMe (THF)] + [B
Ph4]- (Me=methyl group, Ph=phenyl group)
Ethylene polymerization has been successfully carried out using the compound represented by

[0014] Jordan et al. Am. Che
m. Soc. , 109, 4111 (1987)
and [Cp2 ZrR(L)]+ (R=methyl group,
Zirconium complexes such as benzyl group, L = Lewis base) have been shown to polymerize ethylene.

[0015] Special Publication Publication No. 1-501950, Special Publication No. 1-501950
JP-A-502036 describes a method for polymerizing olefins using a catalyst comprising a cyclopentadienyl metal compound and an ionic compound capable of stabilizing the cyclopentadienyl metal cation.

[0016] Zambelli et al.
Ecules, 22, 2186 (1989) reports that isotactic polypropylene can be produced using a catalyst that combines a zirconium compound having a cyclopentadiene derivative as a ligand, trimethylaluminum, and fluorodimethylaluminum.

[0017]

[Problem to be solved by the invention] The above-mentioned Japanese Patent Application Laid-Open No. 2-413
In the method for producing syndiotactic polypropylene according to No. 03 and JP-A-2-274703, the molecular weight of the polymer is determined by the polymerization temperature and the type of catalyst,
In order to obtain syndiotactic polypropylene having a desired molecular weight and good tacticity, there has been a problem in that various catalyst components must be synthesized and used.

[0018]Although the method disclosed in JP-A-2-274703 is an excellent method in which the molecular weight of syndiotactic polypropylene can be adjusted using hydrogen, it has the problem that the polymerization activity changes depending on the amount of hydrogen added. there were.

[0019] The present applicants previously published the above-mentioned Japanese Patent Application Laid-open No. 2-4130.
By polymerizing propylene in the presence of an internal olefin using the catalyst described in Publication No. 3 or a catalyst similar thereto, they succeeded in obtaining syndiotactic polypropylene with a desired molecular weight and good tacticity, and filed an application. However, these methods have the problem that the addition of internal olefins lowers the polymerization activity.

[0020]

[Means for Solving the Problems] The present inventors have conducted intensive studies on a method for solving the above-mentioned problems and producing syndiotactic polypropylene having a desired molecular weight, and have finally completed the present invention.

That is, the present invention provides a method for producing syndiotactic polypropylene by polymerizing propylene, in which (A) general formula (I) (chemical formula 5)

[0022]

embedded image (where A1 and A2 are cyclopentadienyl groups,
Indicates an indenyl group, a fluorenyl group, or a derivative thereof. A3 and A4 represent an aryl group having 6 to 20 carbon atoms, a halogenated aryl group, an alkyl group having 1 to 10 carbon atoms, or a hydrogen atom;
At least one of them is an aryl group or a halogenated aryl group. R1 and R2 represent a halogen atom, a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group. M is titanium, zirconium, or hafnium. Q is a compound containing carbon or silicon, germanium, or tin that connects A1 and A2. ) using a catalyst consisting of a transition metal compound represented by and (B) a co-catalyst,
A method for producing syndiotactic polypropylene, further comprising carrying out polymerization in the presence of an internal olefin. Furthermore, the present invention provides (B) a method for producing syndiotactic polypropylene as described above, characterized in that aluminoxane is used as a co-catalyst component, and (B) an organometallic compound as a co-catalyst component, and (b) a transition metal. The method for producing syndiotactic polypropylene is characterized by using a compound capable of stabilizing cations.

In the transition metal compound represented by the general formula (I) used in the present invention, A1 and A2 represent a cyclopentadienyl group, an indenyl group, a fluorenyl group, or a derivative thereof. Syndiotactic polypropylene can be produced by using specific compounds for A1 and A2. As such suitable examples, A1 and A2 may each be a cyclopentadienyl group, a fluorenyl group; a cyclopentadienyl group, a substituted fluorenyl group; a cyclopentadienyl group, a 4-substituted cyclopentadienyl group, etc. can. A3, A
4 represents an aryl group having 6 to 20 carbon atoms, a halogenated aryl group, an alkyl group having 1 to 10 carbon atoms, or a hydrogen atom, and at least one of A3 and A4 is an aryl group or a halogenated aryl group. It is. A
Specific examples of 3 and A4 include hydrogen atom, methyl group,
Examples include ethyl group, propyl group, phenyl group, tolyl group, chlorophenyl group, dichlorophenyl group, fluorophenyl group, and difluorophenyl group. Q is a compound containing carbon or silicon, germanium, or tin that connects A1 and A2, and is preferably a carbon atom. R1 and R2 represent a halogen atom, a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group, preferably a chlorine atom or a methyl group. M represents titanium, zirconium, or hafnium, preferably zirconium,
It is hafnium.

The transition metal compound represented by the general formula (I) is described, for example, in JP-A-2-274703 and JP-A-2-2.
It can be synthesized using a method similar to the method for synthesizing transition metal compounds described in Japanese Patent No. 74704.

As specific examples of the transition metal compound represented by the general formula (I), in addition to the transition metal compounds described in JP-A-2-274703 and JP-A-2-274704, for example, methyl ( 4-fluorophenyl)methylenecyclopentadienylfluorenylzirconium dichloride, methyl(4-fluorophenyl)methylenecyclopentadienyl(2,7-di-t-butylfluorenyl)zirconium dichloride, methyl(4-fluorophenyl) ) Methylene cyclopentadienyl fluorenyl hafnium dichloride, methyl (4-fluorophenyl)
Methylenecyclopentadienyl (2,7-di-t-butylfluorenyl) hafnium dichloride, bis(4-fluorophenyl)methylenecyclopentadienylfluorenylzirconium dichloride, bis(4-fluorophenyl)methylenecyclopentadi enyl (2,7-dit-
butylfluorenyl) zirconium dichloride, bis(
4-fluorophenyl)methylenecyclopentadienylfluorenyl hafnium dichloride, bis(4-fluorophenyl)methylenecyclopentadienyl(2,7-
Examples include di-t-butylfluorenyl) hafnium dichloride.

[0026] In addition to known aluminoxanes, the co-catalyst used together with the transition metal compound during polymerization includes ionic compounds capable of forming transition metal cations, such as those described in Japanese Patent Publication No. Hei 1-501950, Omotehira 1-
Boron compounds such as those described in Japanese Patent No. 502036 can also be used as promoters. In addition, a co-catalyst consisting of (a) an organometallic compound and (b) a compound capable of stabilizing transition metal cations can also be used. As aluminoxanes, the general formula (Chemical formula 6
)

[0027]

It is a compound represented by [Chemical formula 6] (where R is a hydrocarbon group having 1 to 3 carbon atoms and n is an integer of 2 or more), especially methylaluminoxane where R is a methyl group and n is 5 or more. , preferably 10 or more. There is no problem even if a small amount of an alkyl aluminum compound is mixed in the above aluminoxanes.

[0028] In the present invention, the ratio of aluminoxane to the above transition metal compound is 10 to 10,000.
0 mole times, usually 50 to 10,000 times.

The organometallic compound (a) used in the present invention is a metal compound selected from aluminum, zinc, and magnesium. These organometallic compounds have residues such as halogen, oxygen, hydrogen, alkyl, alkoxy, and aryl as ligands, and these ligands may be the same or different. However, at least one has an alkyl group. For example, an alkyl metal compound in which 1 to n alkyl residues having 1 to 12 carbon atoms are bonded, an alkyl metal halide, an alkyl metal alkoxide, etc. can be used. Among them, alkylaluminum compounds are preferably used, such as trimethylaluminum, triethylaluminum, triisopropylaluminum, tributylaluminum, dimethylaluminum chloride, diethylaluminum chloride, diisopropylaluminum chloride, diisopropylaluminium isopropoxide, ethylaluminum dichloride, ethylaluminum dichloride, and ethylaluminum dichloride. Examples include isopropoxide.

The ratio of the organometallic compound to the transition metal compound used is 1 to 100,000 times by mole, usually 1
It is 0 to 5000 times the mole.

Compounds capable of stabilizing transition metal cations as component (b) used in the present invention include compounds containing anions capable of stabilizing transition metal cations, and electrophilic compounds. can be mentioned.

Compounds containing anions capable of stabilizing transition metal cations include, for example, organoboron compound anions, organoarsenic compound anions, organoaluminium compound anions, etc. Preferably, it does not bind to the transition metal cation compound or strongly coordinate to inactivate the polymerization active species. Examples of such suitable anions include the above-mentioned tetraphenyl boron anion by Taube, Jordan et al.
Tetrakis (pentafluorophenyl) boron anion described in Japanese Patent Publication No. Hei 1-502036 can be mentioned.

The cation to form an ionic compound by pairing with these anions is not particularly limited as long as it does not react with the polymerization active species to inactivate it, and any cation that can pair with the above anions can be used. Known cations can be mentioned. Such cations include metal cations, organometallic cations, carbonium cations, trypium cations, oxonium cations, sulfonium cations, phosphonium cations, ammonium cations, and the like. More specifically, they include silver cation, dicyclopentadienyl iron cation, triphenylcarbenium cation, triphenylphosphonium cation, and tributylammonium cation.

[0034] Also, Marks et al.
r 4, 1212 (1988), electrophilic compounds such as metal oxides and metal halides that act as Lewis acids can also stabilize transition metal cations, and in the present invention such electrophilic compounds can be used to stabilize transition metal cations. An electrophilic compound can be used as component (b). Examples of such compounds include Al2O3,S
Examples include iO2, MgCl2, AlCl3, and the like. The ratio of the compound that reacts with the transition metal compound to form an ionic compound to the above transition metal compound is 0.1 to 10,000 times by mole, usually 0.5 to 5 times by mole.
000 moles.

What is important in the present invention is to contact (A) the transition metal compound with (a) the organometallic compound and then (b) contact with a compound capable of stabilizing the transition metal cation. If this order is different, polymerization will not occur, or even if polymerization occurs, the activity will be very low.

The transition metal catalyst component and/or in the present invention
Alternatively, the co-catalyst can be used as is, such as SiO2, Al2O
3, MgCl2 or the like may be supported on a known carrier supporting a Ziegler type catalyst.

What is important in the present invention is the presence of an internal olefin during propylene polymerization. As the internal olefin, unsaturated compounds having 4 to 20 carbon atoms can be preferably used, specifically, internal monoolefins having 4 to 20 carbon atoms, cyclic olefins, nonconjugated dienes having 5 to 20 carbon atoms, and 4 to 40 carbon atoms. cyclic nonconjugated dienes can be utilized. More specifically, linear internal olefins such as 2-butene, 2-pentene, and 2-hexene, cyclic olefins such as cyclopentene, cyclohexene, cycloheptene, and norbornene, 5-methylene-2-norbornene, and 5-ethylidene-2- Examples include cyclic dienes such as norbornene and dicyclopentadiene. The amount of these internal olefins used varies depending on the molecular weight of the target polypropylene, but is usually 1/100,000 to 1/10 of propylene.

The polymerization method and polymerization conditions carried out in the method of the present invention are not particularly limited, and known methods for polymerizing α-olefins may be used, such as solvent polymerization using an inert hydrocarbon medium or substantially Bulk polymerization methods and gas phase polymerization methods in which no inert hydrocarbon medium is present can also be used, and polymerization temperatures are generally from -100 to 200 DEG C. and polymerization pressures from normal pressure to 100 kg/cm@2. Preferably -50 to 100°C, normal pressure to 50 kg/cm2
It is.

Examples of the hydrocarbon medium used in the treatment or polymerization of the catalyst component in the present invention include butane, pentane, hexane, heptane, octane, nonane,
In addition to saturated hydrocarbons such as decane, cyclopentane, and cyclohexane, aromatic hydrocarbons such as benzene, toluene, and xylene can also be used.

In the present invention, in addition to the homopolymerization of propylene, copolymers of propylene and ethylene or propylene and ethylene or α-olefin having about 2 to 25 carbon atoms, such as propylene and 1-butene, can be produced. Also available.

[0041]

[Examples] The present invention will be specifically explained below with reference to Examples. Example 1 JP-A-2-2 was placed in a 2-liter autoclave that was sufficiently purged with nitrogen.
5 ml of a toluene solution containing 2.0 mg of diphenylmethylenecyclopentadienylfluorenylzirconium dichloride synthesized by the method described in Publication No. 74703 and 0.63 g of methylaluminoxane (degree of polymerization 17.7) manufactured by Tosoh Akzo was charged, Next, 1.0L of liquid propylene
and 0.5 g of norbornene were charged. Polymerization temperature 4
The temperature was set to 0°C, and polymerization was carried out for 1 hour. The obtained syndiotactic polypropylene powder was 119.2 g, and the intrinsic viscosity (hereinafter abbreviated as [η]) of the powder measured in a tetralin solution at 135°C was 3.03 dl/g, 13C-N.
The syndiotactic pentad fraction determined from the ratio of the peak intensity observed at about 20.2 ppm in MR measurement to the peak intensity attributable to all methyl groups was 0.881.

Example 2 Example 1 except that the amount of norbornene used was 1.5 g.
Polymerization was carried out in the same manner. The obtained syndiotactic polypropylene powder was 107.2 g, [η] of the powder was 1.87 dl/g, and the syndiotactic pentad fraction was 0.878.

Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 without using norbornene. The obtained syndiotactic polypropylene powder was 102.2 g, and the [η] of the powder was 4.11.
dl/g, syndiotactic pentad fraction is 0.8
It was 73.

Example 3 In a 2-liter autoclave that was sufficiently purged with nitrogen,
2.0 mg of diphenylmethylenecyclopentadienylfluorenylzirconium dichloride synthesized by the method described in JP 74703 and 60 mg of triethylaluminum
5 ml of a toluene solution containing 1.0 ml of liquid propylene and 0.5 g of norbornene and 15 mg of triphenylcarbeniumtetrakis(pentafluorophenyl)boron were charged. The polymerization temperature was set to 40°C, and polymerization was carried out for 1 hour. The obtained syndiotactic polypropylene powder was 83.2 g, powder [η]
was 2.83 dl/g, and the syndiotactic pentad fraction was 0.858.

Example 4 Example 3 except that the amount of norbornene used was 1.5 g.
Polymerization was carried out in the same manner. The obtained syndiotactic polypropylene powder was 89.6 g,
η] was 1.41 dl/g, and the syndiotactic pentad fraction was 0.846.

Example 5 [Synthesis of transition metal compound] Bis(4-fluorophenyl)fulvene 0.18 mol of cyclopentadienyl sodium T
100 ml of THF solution containing 38 g of difluorobenzophenone was added dropwise to 200 ml of HF solution at room temperature. After stirring for 2 hours at room temperature, 500 ml of ice water and 300 ml
After adding diethyl ether, the ether layer was washed with water and dehydrated with magnesium sulfate, and the solvent was distilled off under reduced pressure to obtain 41.6 g of an orange solid. 21. This orange solid was purified by column chromatography.
9 g of bis(4-fluorophenyl)fulvene was obtained as red crystals. The elemental analysis values of this compound are shown below.

Calculated value (%) C: 81.20 H:
4.51 F: 14.29 Actual value (%)
C: 81.81 H: 4.63 F:
13.88Bis(4-fluorophenyl)cyclopentadienylfluorenylmethane 6.25 g of fluorene was dissolved in 100 ml of THF, and 37.6 mmol of methyllithium was added dropwise to this solution, followed by stirring at room temperature for 5 hours. 10 g of bis(4-fluorophenyl)fulvene synthesized above was added to the obtained red solution.
The mixture was added at 20°C and reacted overnight at room temperature. Add 3. to this reaction solution.
After adding 100 ml of 6% hydrochloric acid water and washing the organic layer with water and dehydrating it with magnesium sulfate, the solvent was distilled off under reduced pressure to obtain 15.4 g of red sticky substance. By purifying this sticky substance with column chromatography, 6.5 g of bis(
4-fluorophenyl)cyclopentadienylfluorenylmethane was obtained.

The elemental analysis values of this compound are shown below. Calculated value (%) C: 86.11 H:
5.09 F: 8.80 Actual value (%)
C: 86.02 H: 4.97 F: 8
．． 94bis(4-fluorophenyl)methylenecyclopentadienylfluorenylzirconium dichloride6.
5g of the above synthesized bis(4-fluorophenyl)cyclopentadienylfluorenylmethane was dissolved in 150ml of THF.
30 mmol of n-BuLi was added dropwise to this solution. After reacting overnight at room temperature, the solvent was distilled off under reduced pressure and the solid obtained was washed with pentane.
350 ml of a dichloromethane slurry containing g of zirconium tetrachloride was added at -78°C. After stirring at -78°C for 4 hours, the mixture was heated to room temperature and further reacted overnight. The reaction slurry was filtered and the filtrate was concentrated to approximately 50 ml. By adding 100 ml of pentane to this concentrated solution, 1.8 g of bis(4-fluorophenyl)methylenecyclopentadienylfluorenyl zirconium dichloride was obtained.The elemental analysis value of this compound is shown below. Calculated value (%) C: 62. 83 H:3.38 F:
6.42 Cl: 11.96 Actual value (%) C: 63.
44 H: 3.50 F: 6.14 Cl: 11
．． 32 [Polymerization] 2.0 mg of bis(4-fluorophenyl)methylenecyclopentadienylfluorenylzirconium dichloride synthesized above as a transition metal compound component
Polymerization was carried out in the same manner as in Example 1 except that . The obtained syndiotactic polypropylene powder was 54.2 g, [η] was 1.95 dl/g, and the syndiotactic pentad fraction was 0.884.

Example 6 Example 5 except that the amount of norbornene used was 1.5 g.
Polymerization was carried out in the same manner as in [Polymerization]. The obtained syndiotactic polypropylene powder was 48.9 g, [η] of the powder was 1.25 dl/g, and the syndiotactic pentad fraction was 0.871.

Comparative Example 2 Polymerization was carried out in the same manner as in Example 5 (polymerization) without using norbornene. The obtained syndiotactic polypropylene powder was 50.7 g, [η] of the powder was 2.48 dl/g, and the syndiotactic pentad fraction was 0.873.

[0051]

EFFECTS OF THE INVENTION By carrying out the method of the present invention, syndiotactic polypropylene having a desired molecular weight can be produced without reducing polymerization activity, which is extremely valuable industrially.

Claims (3)

[Claims] Claim 1. A method for producing syndiotactic polypropylene by polymerizing propylene, comprising: (A) general formula (I) (Formula 1) [Formula 1] (where A1 and A2 are cyclopentadienyl groups,
Indicates an indenyl group, a fluorenyl group, or a derivative thereof. A3 and A4 represent an aryl group having 6 to 20 carbon atoms, a halogenated aryl group, an alkyl group having 1 to 10 carbon atoms, or a hydrogen atom;
At least one of them is an aryl group or a halogenated aryl group. R1 and R2 represent a halogen atom, a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group. M is titanium, zirconium, or hafnium. Q is a compound containing carbon or silicon, germanium, or tin that connects A1 and A2. 1. A method for producing syndiotactic polypropylene, which comprises using a catalyst consisting of a transition metal compound represented by () and (B) a co-catalyst, and further carrying out polymerization in the presence of an internal olefin. 2. The method for producing syndiotactic polypropylene according to claim 1, characterized in that (B) aluminoxane is used as the promoter component. 3. (B) Claim 1, characterized in that (a) an organometallic compound and (b) a compound capable of stabilizing transition metal cations are used as cocatalyst components.
The method for producing syndiotactic polypropylene as described.