JPH0881516A - Transition metal catalyst component for olefin polymerization and method for polymerizing olefin using the same - Google Patents

Abstract

PURPOSE: To improve the efficiency of a catalyst initiator by polymerizing an olefin in the presence of a specific transition metal catalyst. CONSTITUTION: A catalyst is obtd. by combining a transition metal catalyst component for olefin polymn. represented by formula I [wherein CpR'5 is an optionally substd. cyclopentadienyl group; R' is H, a 1-20C hydrocarbon group, a hydrocarbon group of which two carbon atoms may combine with two carbon atoms of the cyclopentadienyl group to form a 4- to 6-membered carbon ring, or silyl; M is Ta or Nb; and 'diene' is a compd. represented by formula II (wherein R<1> to R<6> are each 1-4C alkyl or aryl)] with an organoaluminum compd. represented by formula III or IV (wherein R<7> is a 1-20C hydrocarbon group) in a ratio of the transition metal to aluminum of (1:1)-(1:100,000) or by combining the transition metal catalyst component with an ionized compd. in a ratio of the transition metal to B of the ionized compd. of (0.5/1)-(5:1). An olefin is polymerized at -50 to 250 deg.C in the presence of the catalyst obtd. as above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transition metal catalyst component for olefin polymerization and a method for olefin polymerization using the catalyst component. More specifically, the present invention relates to a novel transition metal catalyst component for olefin polymerization having a cyclopentadienyl ligand and a diene ligand, which is used in combination with aluminoxane and the like, and an olefin polymerization method using the catalyst component.

[0002]

2. Description of the Related Art Conventionally, when an olefin is polymerized in the presence of a catalyst to produce an olefin polymer, a transition metal compound of Group IVB of the periodic table having two cyclopentadienyl ligands is used as a catalyst. The method using an aluminoxane is widely known.

On the other hand, the inventors of the present invention disclosed in Japanese Patent Laid-Open No. 5-31082.
In No. 8, a catalyst component containing Ta and Nb of VB group having a highly active olefin polymerization ability was reported, but it was desired to develop a catalyst component showing a sufficient catalyst initiator efficiency.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a novel organic Nb as a olefin polymerization catalyst component, which has a cyclopentadienyl ligand and a conjugated diene as ligands and exhibits a sufficiently high catalyst initiator efficiency. Alternatively, it is intended to provide a Ta complex and provide a method for polymerizing olefins, especially α-olefins, by a catalyst system in which these are combined with aluminoxane and the like.

The present inventor has previously disclosed a method for synthesizing an organic Nb and Ta complex having only a cyclopentadienyl ligand and a conjugated diene as a ligand (J. Am.
Chem. Soc., 107, 2410 (1985); Organometallics, 7,
2266 (1988); J. Am. Chem. Soc., 110, 5008 (1988)),
There is no description about the use of these compounds as a transition metal component for α-olefin polymerization.

[0006]

The present inventors have arrived at the present invention as a result of earnestly searching for a new catalyst system in order to provide an olefin polymerization method which can replace the above-mentioned conventional technique. That is, the present invention has the general formula

[0007]

Embedded image (CpR ′ ₅ ) M (diene) ₂ [wherein CpR ′ ₅ represents a substituted or unsubstituted cyclopentadienyl group, R ′ is hydrogen which may be the same or different, and has 1 to 1 carbon atoms] 20 hydrocarbon groups, 2 carbon atoms each of which may be bonded to two carbon atoms of a cyclopentadienyl group to form a C ₄ -C ₆ ring, or a silyl group. M is Ta or Nb. diene is a general formula

[0008]

[Chemical 5] (R ^{1 to} R ⁶ are hydrogen, which may be the same or different, an alkyl group or an aryl group having 1 to 4 carbon atoms), and the two conjugated dienes are the same or different. Good. ] It is related with the transition metal catalyst component for olefin polymerization represented by these, and the polymerization method of the olefin characterized by using this catalyst component.

Hereinafter, the present invention will be described in detail. The transition metal catalyst component of the present invention is preferably used for the polymerization of α-olefin in combination with a cocatalyst such as an organoaluminum compound including aluminoxane or an ionic compound. The transition metal catalyst component of the present invention has the general formula

[0010]

Embedded image A transition metal compound having a cyclopentadienyl ligand and a diene ligand represented by (CpR ′ ₅ ) M (diene) ₂ . C in the above general formula
pR ′ ₅ represents a substituted or unsubstituted cyclopentadienyl group.

R'may be the same or different,
It is hydrogen, a hydrocarbon group having 1 to 20 carbon atoms, or a silyl group. Preferred is hydrogen or the aforementioned hydrocarbon group. Examples of the hydrocarbon group include alkyl, aryl, alkenyl, alkylaryl, arylalkyl, etc., preferably alkyl, particularly preferably methyl.

Examples of the cyclopentadienyl group having hydrogen and / or a methyl group as a substituent include a cyclopentadienyl group and a pentamethylcyclopentadienyl group, and among them, a pentamethylcyclopentadienyl group is preferable. preferable. Two hydrocarbon groups bonded to each carbon atoms to form a C ₄ -C ₆ ring carbon 2 carbon atoms cyclopentadienyl group as a hydrogen group used, indenyl group, tetrahydroindenyl group , Fluorenyl group and the like.

Examples of the silyl group include a trimethylsilyl group and a triethylsilyl group. M is Ta or Nb. Nb is particularly preferable. diene is a general formula

[0014]

[Chemical 7] (R ^{1 to} R ⁶ are hydrogen, which may be the same or different, or an alkyl group or an aryl group having 1 to 4 carbon atoms), which is a conjugated diene compound. Examples of the alkyl group having 1 to 4 carbon atoms include methyl, ethyl, propyl and butyl. Specific compounds include butadiene, isoprene, 2,3-dimethyl-1,3-butadiene and 1,4-
Diphenyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 3-methyl-1,3-pentadiene, 2,4-hexadiene and the like can be mentioned. Two conjugated dienes in the same transition metal molecule may be the same or different from each other. Among the conjugated dienes, butadiene, isoprene and 2,3-dimethyl-1,3-butadiene are preferable, and especially 2,3-dimethyl-1,3.
-Butadiene is preferred.

Specific examples of the above transition metal catalyst component include (pentamethylcyclopentadienyl) niobium bis (2,3-dimethyl-1,3-butadiene) and (pentamethylcyclopentadienyl) niobium bis ( Isoprene), (cyclopentadienyl) niobium bis (2,3
-Dimethyl-1,3-butadiene), (pentamethylcyclopentadienyl) niobium (2,3-dimethyl-1,
3-butadiene) (isoprene), (pentamethylcyclopentadienyl) niobium bis (1,3-butadiene), (cyclopentadienyl) niobium bis (1,3-
Butadiene), (pentamethylcyclopentadienyl)
Tantalum bis (2,3-dimethyl-1,3-butadiene), (pentamethylcyclopentadienyl) tantalum bis (isoprene), (cyclopentadienyl) tantalum bis (2,3-dimethyl 1,3-butadiene), (penta Methylcyclopentadienyl) tantalum (2,3-
Dimethyl-1,3-butadiene) (isoprene), (pentamethylcyclopentadienyl) tantalum bis (1,
3-butadiene), (cyclopentadienyl) tantalum bis (1,3-butadiene) and the like.

As a method for synthesizing the transition metal compound of the present invention
Is, for example, Cp * M (diene) ₂(Cp * is a pen
Tamethylcyclopentadienyl group)
Compound is Cp * MX_Four(X represents a halogen element)
Pentamethylcyclopentadienyl halogen represented by
Allyl Grignard corresponding to 2 equivalents of diene
It is obtained by reacting the compound.

The aluminoxane to be combined with the transition metal catalyst component of the present invention during olefin polymerization, particularly α-olefin polymerization, has the general formula

[0018]

Embedded image Or

[0019]

[Chemical 9]

An organoaluminum compound represented by the following is used. R ⁷ is a hydrocarbon group having 1 to 20 carbon atoms, preferably a lower hydrocarbon group having 1 to 4 carbon atoms, and particularly preferably a methyl group. m is an integer of 4 to 30, and particularly preferably 10 or more. As the aluminoxane, those produced by a known method may be used. Examples of the organic aluminum other than aluminoxane include trialkylaluminum such as trimethylaluminum and triethylaluminum. The ratio of the transition metal catalyst component for olefin polymerization of the present invention to the organoaluminum used is 1: 1 in the ratio of the transition metal in the former to Al in the organoaluminum.
It is chosen to be 100,000, preferably 10-2,000. In the present invention, for the transition metal catalyst component,
It is characterized in that desired performance can be obtained by using a small amount of organoaluminum compound.

The transition metal catalyst component for olefin polymerization of the present invention can be used in combination with an ionized compound. Examples of such compounds include triphenylcarbenium tetrakis (pentafluorophenyl) borate, N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate, and tris (pentafluorophenyl) boron.

The ratio of the transition metal catalyst component for olefin polymerization of the present invention to the ionized compound used is 0.5: 1 to 5: 1 in terms of the ratio of B in the transition metal to the ionized compound in the former. As olefins, ethylene, propylene, 1
-Butene, 1-hexene, 3-methylbutene-1,4-
Methylpentene-1, styrene and the like are used. Among them, it is suitable for the polymerization of ethylene. It is also possible to copolymerize these olefins.

The polymerization reaction is carried out using aliphatic hydrocarbons such as butane, pentane, hexane and heptane, alicyclic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as toluene and xylene, and halogenated hydrocarbons such as methylene chloride. It is carried out in the presence or absence of a solvent. The temperature is -5
It is 0 to 250 ° C, preferably -50 to 100 ° C. The pressure is not particularly limited.

Hydrogen may be present as a molecular weight modifier in the polymerization system. The polyethylene obtained as a result of carrying out a polymerization reaction using ethylene as an olefin has a particularly narrow molecular weight distribution (Mw / Mn) and a Mw / Mn value of 1.
The feature is that it is around 1. Further, it can be said that the catalyst initiator efficiency {f (%)} calculated by the following formula is significantly higher than that of the conventional invention, which is also a feature of the present invention. The reason why the efficiency of the catalyst initiator is high is as follows.
Although it is not clear yet, of the two molecules of the conjugated diene contained in the organometallic complex used as the catalyst component, one molecule of the conjugated diene easily undergoes ligand exchange with the α-olefin in the presence of the α-olefin. Since it is involved in the awakening polymerization reaction, the efficiency of the catalyst initiator is, for example, Cp * Nb (DMBD) Cl ₂
(DMBD represents 2,3-dimethyl-1,3-butadiene) as compared with the case of using as a polymerization catalyst component,
It can be explained that it will be much higher.

[0025]

[Equation 1] Here, this formula is applied only to the case where the molecular weight distribution shows a value close to 1, and in that case, the molecular weight distribution is assumed to be 1. )

[0026]

EXAMPLES Next, the present invention will be described more specifically by way of examples, but the present invention is not limited by these examples without departing from the gist thereof. Further, FIG. 1 is a flow chart for facilitating the understanding of the technical contents included in the present invention, and the present invention is not limited by this flow chart without departing from the gist thereof. In the following examples, Cp * represents a pentamethylcyclopentadienyl group and Cp represents a cyclopentadienyl group.

(Synthesis of Transition Metal Catalyst Component-1) Cp * K
And the Me ₃ SiCl Me ₃ obtained by reaction of (Me methyl group) SiCp *, by further reaction with NbCl _5, were synthesized Cp * NbCl _4. Next, this Cp * N
bCl ₄ (1.4 g, 3.7 mmol) in THF 20 m
It was dissolved in 1 and cooled to -78 ° C. THF1 in this solution
Dissolved in 0 ml (2,3-dimethyl-2-butene-
7.4 mmol of 1,4-diyl) magnesium was added dropwise. Hold this solution until it returns to room temperature, then at 30 ° C.
And stirred for 2 hours. The reaction solution was filtered, the filtrate was evaporated under reduced pressure, and then extracted with hexane. As a result of concentrating the solvent, Cp
* Nb (DMBD) ₂ (DMBD = 2,3-dimethyl-
1,3-butadiene) was obtained with a yield of 55%.

(Synthesis of Transition Metal Catalyst Component-2) Instead of using Cp * NbCl ₄ in the above examples, CpNb was used.
The same operation was performed except that Cl ₄ was used. As a result CpN
b (DMBD) ₂ was obtained in a yield of 20%. (Synthesis-3 of Transition Metal Catalyst Component) In Synthesis-1 of transition metal catalyst component, Cp * NbCl ₄ was used instead of Cp * NbCl _4.
* Same operation except that TaCl ₄ was used. As a result, Cp * Ta (DMBD) ₂ was obtained with a yield of 46%.

(Ethylene Polymerization) (Example 1) 5.2 mg (0.013 mmol) of the Cp * Nb (DMBD) ₂ complex obtained above was added to toluene (9.3).
([Nb] = 1.44 mM), and 500 equivalents of methylaluminoxane (manufactured by Tosoh Akzo, MW = 1100) was added to this solution to prepare a catalyst. The color of the solution, which was tan, immediately turned yellow. This solution was stirred at 20 ° C. for 10 minutes and then stirred in the presence of ethylene at 1 atm for 1 hour. The reaction was stopped by removing the gas and then adding hydrochloric acid-acidic methanol to obtain 0.367 g of polyethylene. From this result, the polymerization activity was 24.65 kg PE / hr · mol · a.
The value of tm was obtained. Table 1 shows the results of catalyst initiator efficiency and other factors.
It was shown to. (Examples 2-3) In Example 1, the reaction temperature was 0,-
Polymerization was performed in the same manner as in Example 1 except that the temperature was 20 ° C.
The results are summarized in Table-1.

(Examples 4 to 6) In Example 1, the transition metal catalyst component was Cp * Ta (DMBD) ₂ ([Ta] = 1.
Polymerization was performed in the same manner as in Example 1 except that the reaction temperature was set to the value shown in Table 1. The results are shown in Table-1
Summarized in. (Examples 7 to 9) Example 1 except that the transition metal catalyst component in Example 1 was CpNb (DMBD) ₂ ([Nb] = 1.44 mM) and the reaction temperature was the value shown in Table 1. Polymerization was carried out in the same manner as in. The results are summarized in Table-1. (Comparative Example 1)

Cp * Nb (DMBD) in Example 2
Instead of using ₂ , Cp * Nb (DMBD) Cl ₂ ([N
b] = 1.44 mM) and the polymerization was carried out in the same manner as in Example 1 except that the reaction temperature was the value shown in Table-1. The results are summarized in Table-1. The catalytic activity was the same value as in Example 1, but the catalytic initiator efficiency was low at 27%. (Comparative Example 2) Cp * Nb (DMBD) in Example 3
Instead of using ₂ , Cp * Nb (DMBD) Cl ₂ ([N
b] = 1.44 mM) and the polymerization was carried out in the same manner as in Example 1 except that the reaction temperature was the value shown in Table-1. The results are summarized in Table-1. The catalytic activity was the same as that of Example 1, but the efficiency of the catalyst initiator was as low as 34%.

[0032]

[Table 1]

[0033]

By using the Ta or Nb compound having only the cyclopentadienyl ligand and the diene ligand of the present invention as the transition metal catalyst component for olefin polymerization, an olefin polymer can be efficiently obtained. it can.

[Brief description of drawings]

FIG. 1 is a flowchart showing one embodiment of the present invention.

Claims (2)

[Claims] 1. A compound represented by the general formula: (CpR ′ ₅ ) M (diene) ₂ [wherein CpR ′ ₅ represents a substituted or unsubstituted cyclopentadienyl group, and R ′ may be the same or different. hydrogen, a hydrocarbon group having 20 to no 1 carbon atoms, two of the two combine together C ₄ -C ₆ hydrocarbon group which may form a ring carbon atom of the carbon atoms is a cyclopentadienyl group , Or a silyl group. M is Ta or Nb. diene is a general formula: (R ^{1 to} R ⁶ are hydrogen, which may be the same or different, an alkyl group having 1 to 4 carbon atoms or an aryl group), and the two conjugated dienes are the same or different. Good. ] The transition metal catalyst component for olefin polymerization represented by these. 2. A compound represented by the general formula: (CpR ′ ₅ ) M (diene) ₂ [where CpR ′ ₅ , M and diene are the same as in claim 1. ] The polymerization method of the olefin characterized by using the transition metal represented by these as a catalyst component.