JPH1192487A - Samarium complex - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a samarium complex useful for a catalyst in the polymerization reaction of styrene or ethylene. SOLUTION: This bivalent samarium complex is shown by the formula [Cp* Sm(N(Si(R<1> )(R<2> )(R<3> ))2 )Cp*X(THF)2 ]n (in this formula, X is an alkali metal ion, Cp* is a pentamethylcyclopentadienyl ligand, R<1> , R<2> and R<3> are each an 1-4C alkyl group (pref. methyl group), THF is a tetrahydrofuran ligand, and (n) defines the complex as a polymeric complex having [Cp*Sm(N(Si(R<1> )(R<2> )(R<3> ))2 ) CP*X(THF)2 ] as a repeating unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a novel divalent samarium complex, a polymerization catalyst containing the complex, and a method for polymerizing styrene or ethylene using the complex.

[0002]

2. Description of the Related Art Divalent samarium which is a divalent lanthanoid
The complex of (Sm), conventionally, Cp ^{* -} (pentamethylcyclopentadienyl anion) or I ^- Studies about the complex having a plurality of identical ligand such as has been promoted. Recently, as a lanthanoid complex having a novel ligand, a divalent lanthanoid complex (ArO) ₂ Ln having a bisaryloxide anion (ArO ⁻ ) as a ligand (Ln represents Sm or Yb,
O represents 2,6-di-tert-butyl-4-methylphenoxide anion), indicating that aryl oxide ligands are useful ligands for lanthanoid complexes. (Hou, Z., et al.,
J. Am. Chem. Soc., 117, pp.4421-4422, 1995; Yoshim
ura, T., et al., Organometallics, 14, pp.4858-486
4, 1995; Hou, Z., et al., J. Am. Chem. Soc., 116, p.
p.11169-11170, 1994). However, samarium complexes having different ligands are difficult to synthesize due to ligand rearrangement and the like, and are hardly studied.

For example, a divalent samarium amide complex Sm [N (S
iMe ₃ ) ₂ ] ₂ (THF) ₂ (Me: methyl group; THF: tetrahydrofuran ligand) is reacted with two equivalents of a hydroxyaryl compound such as 2,6-di-tert-butyl-4-methylphenol. , The corresponding divalent samarium aryl oxide complex (Ar
O) ₂ Sm (THF) ₃ is obtained, and when this complex is reacted with I ₂ , trivalent samarium iodide having an aryl oxide ligand: (ArO) ₂ Sm (THF) ₂ I (The Chemical Society of Japan 1995 Spring Meeting, Abstract No. 3H5 / 43, Kyoto; Hou et al., Inorg. Chem., 35, p
p.7190-7195, 1996). Although all of these can be isolated as monomers, they are known to have little utility as catalysts for olefin polymerization and the like.

Recently, [Cp ^* Sm (OAr) Cp ^* K (THF) ₂ ] _n (where Cp ^* represents a pentamethylcyclopentadienyl ligand, and ArO is 2,6-di-tert- A butyl-4-methylphenoxide ligand, THF is a tetrahydrofuran ligand, and n is a polymer complex in which the complex has [Cp ^* Sm (OAr) Cp ^* K (THF) ₂ ] as a repeating unit. Has been proposed (The 70th Annual Meeting of the Chemical Society of Japan, Abstract No. 2B114, March 29, 1996; Rare Earth No. 28, published by The Japan Rare Earth Society, 1996) May 16; Hou
et al., Organometallics, 16, pp. 2963-2970, 1997).
However, there is no suggestion or teaching in these academic reports that these catalysts are useful for olefin polymerization.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel samarium complex which is useful as a catalyst for polymerization of styrene and / or ethylene. The present inventors have previously described (Cp ^* Sm (OAr) C
p ^* Z (THF) ₂ ] _n (where Z represents an alkali metal ion, Cp ^* represents a pentamethylcyclopentadienyl ligand, ArO represents an aryloxide ligand, and THF represents tetrahydrofuran. And n is an integer of [Cp ^* Sm
(OAr) Cp ^* Z (THF) ₂ ] is a polymeric complex with a repeating unit), and the polymerization of styrene and ethylene efficiently and under normal pressure or pressure in the presence of a divalent samarium complex represented by It has been found that the process proceeds (1997 Patent Application No. 54595). The present inventors did further research,
The inventors have found that a novel samarium complex represented by the following formula is useful as a polymerization catalyst, and have completed the present invention.

That is, the present invention provides a method of formula (I): [Cp ^* Sm (N (S
i (R ¹ ) (R ² ) (R ³ )) ₂ ) Cp ^* X (THF) ₂ ] _n (wherein X represents an alkali metal ion and Cp ^* represents a pentamethylcyclopentadienyl ligand. R ¹ , R ² , and R ³ each independently represent an alkyl group having 1 to 4 carbon atoms, THF represents a tetrahydrofuran ligand, and n represents a compound represented by [Cp ^* Sm (N (S (S
i (R ¹ ) (R ² ) (R ³ )) ₂ ) which indicates a polymer complex having Cp ^* X (THF) ₂ ] as a repeating unit). is there. According to a preferred embodiment of the present invention, there is provided a samarium complex wherein X is a potassium ion, and R ¹ , R ² and R ³ are methyl groups.

Further, according to the present invention, the formula (II): Cp ^* Sm (N
(Si (R ⁴ ) (R ⁵ ) (R ⁶ )) ₂ ) Cp ^* Y (THF) ₃ (wherein Y represents an alkali metal ion and Cp ^* represents a pentamethylcyclopentadienyl ligand. , R ⁴ , R ⁵ , and R ⁶ each independently represent an alkyl group having 1 to 4 carbon atoms, and THF represents a tetrahydrofuran ligand). According to a preferred embodiment of the present invention,
There is provided a samarium complex wherein Y is a sodium ion and R ⁴ , R ⁵ and R ⁶ are methyl groups.

[0008] According to another aspect of the present invention, there is provided a polymerization catalyst containing the samarium complex. The polymerization catalyst can be preferably used for polymerization of styrene, polymerization of ethylene, or polymerization of styrene and ethylene, preferably block copolymerization of styrene and ethylene. According to still another aspect of the present invention, polymerization of styrene under normal pressure or pressure in the presence of the samarium complex, polymerization of ethylene,
Alternatively, there is provided a method for performing polymerization of styrene and ethylene, preferably block copolymerization of styrene and ethylene.

[0009]

DETAILED DESCRIPTION OF THE INVENTION In a first embodiment of the method of the present invention,
Formula ^{(I): [Cp * Sm} (N (Si (R 1) (R 2) (R 3)) 2) Cp * X (THF) 2] n
(Wherein X represents an alkali metal ion, Cp ^* represents a pentamethylcyclopentadienyl ligand, and R ¹ , R ² , and R ³ each independently represent an alkyl group having 1 to 4 carbon atoms. And THF is a tetrahydrofuran ligand, and n is a repeating unit of the complex represented by [Cp ^* Sm (N (Si (R ¹ ) (R ² ) (R ³ )) ₂ ) Cp ^* X (THF) ₂ ] A divalent samarium complex represented by the following formula: In a second embodiment of the present invention, a compound of formula (II): Cp ^* Sm (N (Si (R ⁴ ) (R ⁵ )
(R ⁶ )) ₂ ) Cp ^* Y (THF) ₃ (wherein Y represents an alkali metal ion, Cp ^* represents a pentamethylcyclopentadienyl ligand, and R ⁴ , R ⁵ , and R ⁶ Each independently represents an alkyl group having 1 to 4 carbon atoms, and THF represents a tetrahydrofuran ligand).

In the complex of the formula (I), R ¹ , R ² and R ³ are each independently an alkyl group having 1 to 4 carbon atoms, or in the complex of the formula (II) R ⁴ , R ⁵ and R ⁶ the four alkyl groups 1 -C each independently represent a straight-chain or branched-chain alkyl groups such as methyl group, ethyl group, n- propyl group, an isopropyl group, n- butyl group, tert
-A butyl group or the like can be used. Of these,
A complex wherein R ¹ , R ² , and R ³ are all methyl groups, and
A complex in which R ⁴ , R ⁵ and R ⁶ are all methyl groups is preferred.

In the complex represented by the formula (I), X can be an alkali metal ion such as a potassium ion or a sodium ion, and preferably a potassium ion. In the above complex,
n indicates that this complex is crosslinked by Cp ^{* in the} complex,
It shows that it has a polymer structure having [Cp ^* Sm (N (Si (R ¹ ) (R ² ) (R ³ )) ₂ ) Cp ^* X (THF) ₂ ] as a repeating unit.
The number of the repeating units (so-called degree of polymerization) in the complex represented by the above formula is not particularly limited, and any of those having a substantially polymeric structure can be used in the method of the present invention. In the complex represented by the formula (II), as Y 2, an alkali metal ion such as a potassium ion or a sodium ion can be used, and preferably, a sodium ion can be used.

The method for producing the samarium complex of the present invention represented by the formulas (I) and (II) is not particularly limited, and may be produced by any method. One example of a suitable production method is specifically shown in Examples of the present specification, but the production method of the complex of the present invention is not limited to these methods. (Cp ^* ) ₂ Sm (THF) ₂ used as a raw material is described, for example, in the report of Evans et al. (Evans et al., J. Am. Chem. Soc., 107, pp. 941-9).
46, 1985).

The samarium complex of the present invention represented by the formulas (I) and (II) is used as a polymerization catalyst in a polymerization reaction such as polymerization of styrene, polymerization of ethylene, or copolymerization of styrene and ethylene. be able to. However, the use of the complex of the present invention is not limited to a polymerization catalyst. The complex of the present invention can be carried out, for example, in an inert solvent such as toluene using a catalyst in an amount of about 0.0002 to 0.005 mol, preferably about 0.001 to 0.002 mol, per 1 mol of the monomer.

As the styrene or ethylene used as a monomer, in addition to unsubstituted styrene and ethylene, those having one or more substituents such as a lower alkyl group on a phenyl ring or a carbon atom constituting a double bond can be used. May be used. As used herein, the terms "styrene" and "ethylene" are used as a concept including unsubstituted styrene and substituted styrene, and unsubstituted ethylene and substituted ethylene, and two or more monomers selected from the group consisting of these substances. May be used in appropriate combination. The catalyst of the present invention is particularly useful for copolymerizing styrene and ethylene,
In particular, it is extremely useful for block copolymerizing both.

The concentration of the monomer in the solution is not particularly limited, but may be, for example, 1 to 20% (V / V), preferably 10%
The reaction can be performed at a concentration of about (V / V). When the complex of the present invention is used as a polymerization catalyst, the reaction may be carried out at normal pressure or under pressure. When the reaction is carried out under pressure, for example, the reaction can be carried out at 1,000 atm or more, preferably at 2,000 atm or more, more preferably at about 2,500 atm. When polymerizing styrene, the weight average molecular weight is increased by increasing the monomer concentration in the reaction system.
It is possible to produce more than 100,000, preferably more than 500,000 polymers. The polymerization temperature is not particularly limited, and the polymerization can be carried out at a temperature from room temperature to about 100 ° C (for example, about 60 ° C).

[0016]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples, but the scope of the present invention is not limited to these Examples. Example ^{1: [Cp * Sm (N} (SiMe 3) 2) Cp * K (THF) 2] Production of _n (Me
Represents a methyl group.) In tetrahydrofuran (10 ml), (Cp ^* ) ₂ Sm (THF) ₂ (0.2
mmol) and Sm (N (SiMe ₃ ) ₂ ) ₂ (THF) ₂ (0.2 mmol) and then (Cp ^* ) K (0.4 mmol) to give a green solution. After stirring at room temperature for 4 hours, the solution was filtered and concentrated under reduced pressure. Toluene was added for crystallization to obtain the target needle-like crystals (yield 90%).

When the single crystal of this complex was subjected to X-ray analysis, the following crystal data was obtained, and this crystal was identified as [Cp ^* Sm (N (S
It was confirmed that Cp ^* had a crosslinked polymeric structure using iMe ₃ ) ₂ ) Cp ^* K (THF) ₂ ] as one unit. a = 35.013 (10); b = 10.306 (5); c = 11.684 (3) Å β = 104.00 (3) ° Unit volume: 4091 (3) Å ³ ; Crystal system: monoclinic; Space group: C2 , Z = 4, Dcalcd = 1.24 g / cm
³ , R = 6.51%.

Example 2: Preparation of Cp ^* Sm (N (SiMe ₃ ) ₂ ) Cp ^* Na (THF) _{3 In} tetrahydrofuran (10 ml), (Cp ^* ) ₂ Sm (THF) ₂ (0.2
After adding mmol) and Sm of the _{(N (SiMe 3) 2)} 2 (THF) 2 (0.2 mmol), was dissolved in tetrahydrofuran ^{(10 ml) (Cp *)} Na
(0.4 mmol) gave a green solution. After stirring at room temperature for 4 hours, the solution was filtered and concentrated under reduced pressure. Toluene was added for crystallization to obtain the desired crystal (yield
90%). X-ray analysis was performed on the single crystal in the same manner as in Example 1. a = 17.716 (6); b = 18.188 (5); c = 14.379 (4) Å β = 94.13 (3) ° Unit volume: 4621 (2) Å ³ ; Crystal system: monoclinic; Space group: P21 / n. Z = 4, Dcalcd = 1.18
g / cm ³ , R = 7.80%.

Example 3: Polymerization reaction using the complex of the present invention Using the complex obtained in Example 1, styrene was polymerized. Example 1
Complex (0.05 mmol) and styrene (4 ml) were dissolved in toluene (1
0 ml) and reacted at room temperature for 15 minutes to obtain 3.7 g of polystyrene (Mn = 82,000, Mw / Mn = 2.4
Five). Further, the complex (0.05 mmol) obtained in Example 1 and ethylene (1
atm) was added to toluene (25 ml) and reacted at room temperature for 30 minutes.Polyethylene 0.55 g (Mn = 5.1 × 10 ⁶ , Mw /
Mn = 5.70) was obtained. Similarly, the complex obtained in Example 2 (0.05 m
mol) and ethylene (1 atm) in toluene (25 ml) and reacted at room temperature for 30 minutes.
(Mn = 940,000, Mw / Mn = 4.1) was obtained.

[0020]

The samarium complex of the present invention is useful as a polymerization catalyst for polymerization of styrene or ethylene.

Claims (7)

[Claims] (1) Formula (I): [Cp ^* Sm (N (Si (R ¹ ) (R ² ) (R ³ )) ₂ )
Cp ^* X (THF) ₂ ] _n (wherein X represents an alkali metal ion, Cp ^* represents a pentamethylcyclopentadienyl ligand, and R ¹ , R ² , and R ³ are each independently a carbon atom Represents an alkyl group of several to four, THF represents a tetrahydrofuran ligand, and n represents the complex represented by [Cp ^* Sm (N (Si (R ¹ ) (R ² ) (R ³ ))
₂ ) a divalent samarium complex represented by the formula: Cp ^* X (THF) ₂ ]. 2. The samarium complex according to claim ¹ , wherein X is a potassium ion, and R ¹ , R ² , and R ³ are methyl groups. 3. The formula (II): Cp ^* Sm (N (Si (R ⁴ ) (R ⁵ ) (R ⁶ )) ₂ ) Cp
^* Y (THF) ₃ (where Y represents an alkali metal ion and Cp
^* Indicates a pentamethylcyclopentadienyl ligand,
R ⁴ , R ⁵ , and R ⁶ each independently represent an alkyl group having 1 to 4 carbon atoms, and THF represents a tetrahydrofuran ligand). 4. Y is a sodium ion, R ⁴ , R ⁵ ,
4. The samarium complex according to claim 3, wherein R ⁶ is a methyl group. 5. A polymerization catalyst comprising the samarium complex according to claim 1. Description: 6. The polymerization catalyst according to claim 5, for performing styrene polymerization, ethylene polymerization, or copolymerization of styrene and ethylene. 7. A method for carrying out styrene polymerization, ethylene polymerization, or styrene and ethylene copolymerization in the presence of the samarium complex according to any one of claims 1 to 4 under normal pressure or pressure.