JPH10251319A - Polymerization - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for polymerizing styrene or ethylene by using a divalent samarium complex. SOLUTION: Styrene and/or ethylene is polymerized in the presence of a divalent samarium complex expressed by the formula: [Cp*Sm(ArO)Cp*X (THF)2 ]n X is an alkali metal ion; Cp* is a pentamethylcyclopentadienyl ligand; ArO is an aryloxide ligand; THF is a tetrahydrofuran ligand; (n) means that the complex is a polymeric complex} or the formula: (ArO)2 Sm(THF)3 , preferably under a pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for polymerizing styrene and / or ethylene using a divalent samarium 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 It is known that it can be obtained (Chemical Society of Japan 1995 Spring Meeting, Abstract No. 3H5 / 43, Kyoto City). 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). However, there is no suggestion or teaching in these academic reports that these catalysts are useful for olefin polymerization.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a method for polymerizing styrene and / or ethylene using a samarium complex as a catalyst, preferably a method for block copolymerizing styrene and ethylene. Is what you do. The present inventors have determined the above [Cp ^* Sm (OAr) Cp
^* K (THF) ₂ ] that the samarium complex represented by _n is useful for the polymerization of styrene and / or ethylene, and that the polymerization reaction proceeds under normal pressure and pressure, and particularly excellent yield under pressure It has been found that block copolymers of polystyrene and / or polyethylene, preferably styrene and ethylene, can be produced. The present inventors have also found that the use of a samarium complex represented by (ArO) ₂ Sm (THF) ₃ allows the above polymerization reaction to proceed efficiently under pressure. The present invention has been completed based on these findings.

That is, the present invention provides a compound represented by the formula: (ArO) ₂ Sm (THF)
It is intended to provide a method for polymerizing styrene and / or ethylene under a pressure of 1,000 atm or more in the presence of a divalent samarium complex represented by ₃ (ArO represents an aryl oxide ligand). According to a preferred embodiment of the present invention, a complex wherein the aryl oxide ligand is a 2,6-di-tert-butyl-4-methylphenoxide ligand or a 2,6-di-tert-butylphenoxide ligand The above-mentioned method of performing polymerization using the same; and the above-mentioned method of performing copolymerization of styrene and ethylene, preferably block copolymerization of styrene and ethylene are provided.

According to another aspect of the present invention, there is provided a compound represented by the formula:
[Cp ^* Sm (OAr) Cp ^* X (THF) ₂ ] _n (where X represents an alkali metal ion, Cp ^* represents a pentamethylcyclopentadienyl ligand, and ArO represents an aryloxide ligand And THF represents a tetrahydrofuran ligand, and n represents that the complex is a polymeric complex having [Cp ^* Sm (OAr) Cp ^* X (THF) ₂ ] as a repeating unit. The present invention provides a method for performing polymerization of styrene and / or ethylene at normal pressure or under pressure in the presence of a valent samarium complex. According to a preferred embodiment of the present invention, a complex wherein the aryl oxide ligand is a 2,6-di-tert-butyl-4-methylphenoxide ligand or a 2,6-di-tert-butylphenoxide ligand The above method of performing polymerization using styrene and ethylene, preferably the above method of performing block copolymerization of styrene and ethylene; and the above method of performing polymerization under a pressure of 1,000 atm or more are provided. .

[0008]

DETAILED DESCRIPTION OF THE INVENTION In a first embodiment of the method of the present invention,
A catalyst of the formula (I): [Cp ^* Sm (OAr) Cp ^* X (THF) ₂ ] _n (wherein X represents an alkali metal ion, Cp ^* represents a pentamethylcyclopentadienyl ligand, ArO represents an aryloxide ligand, THF represents a tetrahydrofuran ligand, and n represents that the complex is a polymeric complex having [Cp ^* Sm (OAr) Cp ^* X (THF) ₂ ] as a repeating unit. Using a divalent samarium complex represented by the following formula) under normal pressure or pressure to polymerize styrene and / or ethylene, preferably copolymerize styrene and ethylene, and more preferably perform block copolymerization of styrene and ethylene. It is characterized by.

In a second aspect of the present invention, the compound of formula (II):
Using a divalent samarium complex represented by (ArO) ₂ Sm (THF) ₃ (ArO represents an aryl oxide ligand), polymerization of styrene and / or ethylene, preferably copolymerization of styrene and ethylene, Preferably, the block copolymerization of styrene and ethylene is performed under a pressure of 1,000 atm or more.

In the complexes of the formulas (I) and (II), a substituted phenoxide anion can be preferably used as the aryl oxide ligand, and the substituted phenoxide anion may be, for example, one or more on the benzene ring. Those substituted with two or more, preferably two or three alkyl groups can be used. When it has two or more alkyl groups on the benzene ring, these alkyl groups may be the same or different, and two of these alkyl groups are respectively in the 2-position and the 6-position ( The carbon atom substituted by the oxide group in the benzene ring of phenoxide
To form a 2,6-dialkyl-substituted phenoxide anion.

As the alkyl group to be substituted at the 2-position and the 6-position on the benzene ring, a sterically bulky C ₃ group such as an isopropyl group, a tert-butyl group or a neopentyl group is used from the viewpoint of the stability of the complex. it is preferred to use -C ₆ alkyl group. For example, 2,6-di-tert-butylphenoxide anion, 2,6-diisopropylphenoxide anion, 2,6-dineopentylphenoxide anion, 2-tert-butyl-6
-Isopropylphenoxide anion, 2-tert-butyl
-6-neopentylphenoxide anion or 2-isopropyl-6-neopentylphenoxide anion can be used. Of these, a phenoxide anion in which both the 2- and 6-positions of the benzene ring are substituted with a tert-butyl group (2,6-di-tert-butylphenoxide anion) is particularly preferred.

When the benzene ring of these 2,6-dialkyl-substituted phenoxide anions has one or more, preferably one, alkyl group, the alkyl group may be C ₁ -C _4. An alkyl group is preferable, and the substitution position of the alkyl group is preferably the 4-position. For example, C ₁ -C ₄ such as a methyl group or an ethyl group at the 4-position of the benzene ring of a 2,6-dialkyl-substituted phenoxide anion
A complex having a phenoxide anion into which an alkyl group has been introduced as a ligand is preferable from the viewpoint of solubility and the like.
More specifically, the ligand is 2,6-di-tert-butyl-4-
Complexes having a methylphenoxide anion can be particularly suitably used in the method of the present invention.

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 (OAr) 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.

The complex represented by the formula (II) can be prepared by a known method (for example, Jesorka, A. et al., The Chemical Society of Japan, 1995 Spring Meeting,
Abstract No. 3H5 / 43, Kyoto, 1995; Inorg. Chem., 35,
pp. 7190-7195, 1996), the divalent samarium amide complex Sm [N (SiMe ₃ ) ₂ ] ₂ (THF) ₂ (SiMe ₃ : trimethylsilyl group) is easily reacted with two equivalents of a hydroxyaryl compound. Can be manufactured. As the hydroxyaryl compound, a compound corresponding to a desired aryl oxide ligand may be used, for example, 2,6-di-ter
When the t-butyl-4-methylphenoxide anion is introduced as a ligand, the hydroxyaryl compound 2,6-di-
-tert-butyl-4-methylphenol may be used. The complex represented by the formula (I) is obtained by converting the complex represented by the formula (II) into two equivalents of Cp ^* X (X and Cp ^* are as described above, and X is preferably a potassium ion) and tetrahydrofuran. The reaction can be carried out at a high yield by reacting in a solution.

The polymerization of styrene and / or ethylene using these catalysts is carried out, for example, in an inert solvent such as toluene in an amount of about 0.0002 to 0.005 mole, preferably about 0.001 to 0.002 mole, per mole of monomer. It can be performed using a catalyst. As styrene or ethylene used as a monomer, in addition to unsubstituted ones, those having one or two or more substituents such as a lower alkyl group or a halogen atom on a phenyl ring or a carbon atom constituting a double bond may 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 method of the present invention is particularly useful for copolymerizing styrene and ethylene, and is particularly useful for block copolymerizing both.

The concentration of the above monomer in the solution is not particularly limited, but is, for example, 1 to 20% (V / V), preferably 10%
The reaction can be performed at a concentration of about (V / V). When the catalyst of the formula (I) is used, the polymerization reaction may be carried out at normal pressure, but the reaction is preferably carried out under pressure. For example, 1,00
The reaction may be carried out under a pressure of at least 0 atm, preferably at least 2,000 atm, more preferably about 2,500 atm. Also,
When polymerizing styrene, a polymer having a weight average molecular weight of 100,000 or more, preferably 500,000 or more can be produced by increasing the monomer concentration in the reaction system. formula
When using the catalyst of (II), it is necessary to carry out the polymerization reaction under pressure, for example, at least 1,000 atm, preferably 2,0 atm.
The reaction can be carried out under a pressure of at least 100 atm, more preferably about 2,500 atm. The polymerization temperature is not particularly limited,
The polymerization can be carried out at room temperature or under heating up to about 100 ° C (for example, about 60 ° C).

[0017]

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: Sm [N (SiMe ₃ ) ₂ ] ₂ (THF) ₂ (4.44 g, 7.21 mmol) was dissolved in tetrahydrofuran (50 ml) and 2,6-ditert-butyl-4 dissolved in 20 ml of tetrahydrofuran. -
Methylphenol (3.18 g, 14.42 mmol) was added, and the mixture was stirred at room temperature for 2 hours. The residue obtained by distilling off the solvent under reduced pressure was washed with hexane and recrystallized from tetrahydrofuran / toluene to form a phenoxide-samarium complex Sm (OAr) ₂ (TH
F) ₃ (OAr: 2,6-di-tert-butyl-4-methylphenoxide ligand: complex 1) was obtained as dark brown crystals (4.81 g, 5.9).
7 mmol, 83% yield). Anal.Calcd. For C ₄₂ H ₇₀ O ₅ Sm: C, 62.67%; H, 8.76%.
Found: C, 62.30%, H, 8.81%.

The above complex Sm (OAr) ₂ (THF) ₃ (0.805 g, 1.00
mmol) in 10 ml of tetrahydrofuran, and Cp ^* K
(0.35 g, 2.01 mmol) in tetrahydrofuran (2 m
l) and stirred at room temperature for about 18 hours. After the reaction solution was filtered and the mother liquor was concentrated under reduced pressure, tetrahydrofuran was added to the residue, and the precipitate was filtered off to obtain a dark green mother liquor. The mother liquor was concentrated for crystallization, and tetrahydrofuran was further added, and the precipitate was filtered off to obtain a green-brown mother liquor. The solvent of this liquid separation was distilled off to crystallize the residue, and the obtained crystals were collected by filtration and recrystallized from tetrahydrofuran to give a samarium complex.
[Cp ^* Sm (OAr) Cp ^* K (THF) ₂ ] _n (ArO: 2,6-ditert-butyl-4-methylphenoxide ligand: complex 2) was obtained. Anal.Calcd .: C, 62.72%; H, 8.45%. Found: C, 63.3
9%, H, 8.11%.

Single crystal of this complex (0.40 × 0.35 × 0.20 mm)
Was subjected to X-ray analysis to obtain the following crystal data.
This crystal has [Cp ^* Sm (OAr) Cp ^* K (THF) ₂ ] as one unit.
It was confirmed that Cp ^* had a crosslinked polymeric structure. a = 13.002 (3); b = 17.202 (4); c = 10.373 (6) Å α = 91.40 (3) °; β = 103.97 (3) °; γ = 100.38 (2) ° Unit volume: 2209 (1 ) Å ³ ; crystal system: triclinic; space group:
P-1 (# 2)

Example 2 Using the samarium complex obtained in Example 1, polymerization of styrene, polymerization of ethylene, and copolymerization of styrene and ethylene were carried out. For styrene polymerization, at normal pressure (1 atm), samarium catalyst (0.1 mmol) in toluene (12 ml)
And a reaction solution containing styrene (1.2 ml) under pressure.
(2500 atm), a reaction solution containing a samarium catalyst (0.1 mmol) and styrene (1.5 ml) in toluene (3.5 ml) was used. For the polymerization of ethylene, toluene
(10 ml) and samarium catalyst (0.05 mmol) and ethylene (1
(Atmospheric pressure). For the copolymerization, a reaction solution containing a samarium catalyst (0.05 mmol), styrene (6 ml), and ethylene (1 atm) in toluene (10 ml) was used. The reaction temperature and reaction time, and the yield and molecular weight of the polymer are shown in Table 1 (St and
Et indicates styrene and ethylene, respectively, and St / Et indicates a combination of styrene and ethylene). From these results, the above divalent samarium complex polymerizes styrene,
And it is clear that it is useful for copolymerization of styrene and ethylene.

[0021]

[Table 1] 錯 体 Complex monomer Temperature P / atm Time (h) Yield Mw ³⁾ × 10 ^-4 Mw / Mn ⁴⁾錯 体 complex 1 ¹⁾ St 25 ℃ 2500 2 64% 2.67 1.29 Complex 2 ²⁾ St 0 1 4 20% 40.7 1.87 〃 St 25 1 4 70% 44.5 2.76 〃 St 60 1 1.5 100% 20.2 2.16 〃 St 25 2500 2 100% 59.5 2.84 〃 Et 25 1 0.17 1.55g ⁵⁾ 124.0 2.75 〃 St / Et 25 1 1.5 1.1g ^{5) 6)} 21.7 2.30 〃 ──────── ¹⁾ Sm (OAr) ₂ (THF) ₃ ; ArO is 2,6-di-tert-Bu-4-Me-phenoxy group ²⁾ [Cp ^* Sm (OAr) Cp ^* K (THF) ₂ ] _n ; ArO is 2,6-di-tert-Bu-4-Me-phenoxy group ³⁾ Weight average molecular weight of product ⁴⁾ Number average molecular weight of product ⁵⁾ Product yield (g) ⁶⁾ Styrene / ethylene = 0.65

[0022]

According to the method of the present invention, styrene and / or ethylene can be efficiently polymerized using a divalent samarium complex. In particular, according to the method of the present invention,
This is useful because block copolymerization of styrene and ethylene, which has hardly been reported so far, can be carried out.

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification symbol FI // (C08F 210/02 212: 08)

Claims (7)

[Claims] 1. The formula: [Cp ^* Sm (OAr) Cp ^* X (THF) ₂ ] _n , wherein X represents an alkali metal ion, Cp ^* represents a pentamethylcyclopentadienyl ligand, ArO represents an aryloxide ligand, THF represents a tetrahydrofuran ligand, and n represents that the complex is a polymeric complex having [Cp ^* Sm (OAr) Cp ^* X (THF) ₂ ] as a repeating unit. A) polymerization of styrene and / or ethylene at normal pressure or under pressure in the presence of a divalent samarium complex represented by 2. X is a potassium ion, and the aryloxide ligand is a 2,6-di-tert-butyl-4-methylphenoxide ligand or a 2,6-di-tert-butylphenoxide ligand. The method according to claim 1, wherein the polymerization is carried out using a complex. 3. The method according to claim 1, wherein a block copolymerization of styrene and ethylene is carried out. 4. The process according to claim 1, wherein the polymerization is carried out under a pressure of at least 1,000 atm. 5. In the presence of a divalent samarium complex represented by the formula: (ArO) ₂ Sm (THF) ₃ (ArO represents an aryl oxide ligand), styrene and / or A method for conducting polymerization of ethylene. 6. An aryl oxide ligand comprising 2,6-di-tert-
Butyl-4-methylphenoxide ligand or 2,6-di-tert-
The method according to claim 5, wherein the polymerization is carried out using a complex that is a butylphenoxide ligand. 7. The method according to claim 5, wherein block copolymerization of styrene and ethylene is carried out.