JP6015443B2 - Method for purifying crosslinked indenyl compounds - Google Patents

Description

  The present invention relates to a method for purifying a bridged indenyl compound, and more specifically, by reacting a bridged indenyl compound used as a ligand constituting a metallocene complex of a metallocene catalyst with a base compound, This is a technique related to a purification method for isolating the bridged indenyl compound in a high yield by utilizing the change in solubility.

  Polyolefin, an extremely important polymer material in industry, has been industrially produced on a large scale by Ziegler-Natta catalysts. Recently, it has higher catalytic activity than Ziegler-Natta catalysts, and has a unique stereoregulation. Advantageous metallocene catalysts have been widely used, such as bringing about properties and narrowing the molecular weight distribution.

  The metallocene complex forming the metallocene catalyst is basically synthesized from a ligand compound as a precursor thereof. A bridged indenyl compound is used as a ligand compound of the indenyl metallocene complex most widely known as a metallocene complex because of its high catalytic performance. (For example, see Patent Document 1)

  The bridged indenyl compound is usually synthesized by reacting a corresponding indene compound with a crosslinking agent such as dialkyldichlorosilane, but when synthesizing a metallocene complex from the bridged indenyl compound, impurities such as unreacted indene compound are synthesized. A purification step is required to remove.

As a purification technique utilized industrially, there is a method of recrystallization using an organic solvent, but purification of a bridged indenyl compound is not always easy.
The reason is as follows. Recrystallization is a general-purpose technique, but this technique requires that the compound to be purified has a relatively low solubility in the solvent. However, since a crosslinked indenyl compound having a high utility value is readily soluble in industrially used solvents, the target crosslinked indenyl compound does not sufficiently precipitate, and it has been difficult to efficiently purify by recrystallization.

In order to solve this problem, there is known a method of isomerizing a 1,2-ethylenebisindenyl compound as a ligand compound of a metallocene complex, recrystallizing it after changing its solubility (Patent Document) 2).
In this method, a mixture of isomers having different positions of the double bond of the indenyl moiety is treated with a base in a tetrahydrofuran solution to converge to a thermodynamically stable isomer, and tetrahydrofuran is exchanged with hexane for recrystallization. However, the isomer ratio of the two isomer mixtures resulting from the asymmetry of the carbon atom on the indenyl ring bonded to the silicon or germanium bridging group is almost unchanged even when treated by this method. Therefore, the yield of the crosslinked indenyl compound was insufficient.

On the other hand, for dimethylsilylene-bridged indenyl bridged compounds, there are isomers due to the asymmetry of carbon atoms on the indenyl ring bonded to silicon, and a reaction in which these isomerize at high temperatures is known ( (Refer nonpatent literature 1).
However, it was unclear whether this isomerization reaction proceeds even with a bridged indenyl compound as described in Patent Document 1.

  In view of the above state of the prior art, in particular, a bridged indenyl compound used for a bridged indenyl metallocene complex, most widely known as a metallocene complex, particularly silicon or germanium, which can increase the melting point and molecular weight of the polymer. A compound that is difficult to purify by recrystallization, such as an indenyl compound that binds to a bridging group, can be used for general purposes, and can be used industrially by a simple and easy technique and in a high yield. It is desired to realize a separation and purification method that can be sufficiently separated.

Japanese Patent Laid-Open No. 06-100579 Special table 2003-529534 gazette

Organometallics, 1995, 14, 14, 798

  In view of the above-mentioned problems in the background art, a bridged indenyl compound, particularly a silicon or germanium bridge, used for a bridged indenyl metallocene complex, which is most widely known as a metallocene complex, can increase the melting point and molecular weight of the polymer. Even a compound that is difficult to purify by recrystallization, such as an indenyl compound that binds to a group, can be used for general purposes, and can be used industrially by a simple and easy technique and in a high yield. It is an object of the present invention to solve the problem of separation and purification that can be sufficiently isolated.

In order to solve this problem, the inventor of the present application has made many thoughts in a separation method based on a difference in solubility and a chemical separation method using a separating agent, and in the process of multifaceted experimental examination, It was recognized that the separation and purification based on the difference in solubility with the aid of the chemical method described above was effective for solving the above problems.
As a result of consideration and trial from such a viewpoint, in a crosslinked indenyl compound crosslinked with a silicon atom or a germanium atom, an isomerization reaction between isomers of the crosslinked indenyl compound proceeds by acting a specific base compound. As a result, the solubility can be improved, and a separation and purification method capable of separating the bridged indenyl compound can be easily and very effectively separated, and the present invention has been created. .

  That is, in a crosslinked indenyl compound crosslinked with a silicon atom or a germanium atom, there are isomers resulting from the asymmetry of carbon atoms on the indenyl ring bonded to silicon or germanium, as shown in the following scheme. These two isomers exhibit different properties as a compound, such as solubility in a solvent.

Here, the basic feature of the present invention is that the isomerization reaction between the above two isomers proceeds by acting a base compound, and is converted into an isomer with relatively low solubility, The method comprises a purification method of a bridged indenyl compound that is isolated by efficient crystallization.
In addition, the bridged indenyl compound separated and purified by the above method is the same dimetalated bridged indenyl compound in which the asymmetric source causing isomer formation has disappeared by an appropriate metalation reaction when a metallocene complex is synthesized. Therefore, the same metallocene complex can be synthesized from any isomer.

  Specifically, the invention of the present application is a bridged indenyl compound which is simple but very effective by improving the solubility of a crosslinked indenyl compound crosslinked with a silicon atom or a germanium atom by acting a specific base compound. An essential feature is the isolation of the compound.

  Further, the present invention also provides details of the types of substituents in the base compound to be reacted with the crosslinked indenyl compound, the solvent for the recrystallization method, or the crosslinked indenyl compound to which the present invention can be applied, their positions and the number of substituents, and the crosslinking group. It prescribes.

  Accordingly, the present invention is composed of the following invention groups, and consists of the inventions of the embodiments or the application inventions [2] to [6], centering on the basic invention [1].

[1] According to the first invention of the present invention, the following steps (1) and (2) are performed on a mixture containing a crosslinked indenyl compound having a general formula represented by the following formula (I): Provides a method for purifying a bridged indenyl compound, characterized in that the bridged indenyl compound is separated.

[Wherein R ¹ and R ¹¹ may be the same or different from each other, and may be a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 30 carbon atoms which may have a substituent, They are an alkoxy group having 1 to 6 carbon atoms, an amino group having an alkyl group having 1 to 6 carbon atoms, and a 5- to 10-membered heterocyclic substituent.
R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a carbon number. An alkenyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 30 carbon atoms which may have a substituent, and a 5- to 10-membered heterocyclic substituent.
Q is a divalent silylene group having a substituent or a divalent germylene group having a substituent, and represents a group that bridges two indenyl rings. ]
Step (1) Step (2) of reacting the compound of formula (I) with a base compound From the reaction mixture obtained in step (1), the compound represented by formula (I) is obtained by recrystallization or solid-liquid separation. Isolation process

[2] According to a second invention of the present invention, there is provided a method for purifying a bridged indenyl compound according to the first invention, wherein the base compound is an alkali metal alkoxide.
[3] According to the third invention of the present invention, there is provided a method for purifying a crosslinked indenyl compound, characterized in that the reaction solvent used in the first or second invention is selected from methanol, ethanol, and 2-propanol. Is done.
[4] According to the fourth invention of the present invention, in the first to third inventions, one or both of R ¹ and R ¹¹ is always a furyl group, a thienyl group, a furyl group having a substituent, or a substituent. There is provided a method for purifying a bridged indenyl compound, which is any one of thienyl groups having the following formula.
[5] According to the fifth invention of the present invention, in the first to fourth inventions, one or both of R ³ and R ¹³ may have a substituent and an aryl group having 6 to 30 carbon atoms. Alternatively, a method for purifying a bridged indenyl compound, which is a 5- to 10-membered heterocyclic substituent, is provided.
[6] According to a sixth invention of the present invention, there is provided a method for purifying a crosslinked indenyl compound according to the first to fifth inventions, wherein Q is a dialkylsilylene group or a dialkylgermylene group. The

By the way, the present invention uses a difference in solubility in a specific solvent between two isomers resulting from asymmetry of carbon atoms on an indenyl ring bonded to a silicon or germanium bridging group. However, it is a method of isolating a bridged indenyl compound having a very high yield and high purity effectively.
That is, by causing a specific solvent containing a basic compound sufficient to deprotonate the hydrogen on the asymmetric carbon to act on the above isomer mixture, an isomer having low solubility is selectively precipitated. The highly soluble isomer is again protonated via an intermediate having a cyclopentadienyl anion structure by a base-proton exchange reaction (equilibrium reaction) on an asymmetric carbon in a specific solvent phase. Thus, it is possible to easily and efficiently isolate a bridged indenyl compound having a high purity by changing to an isomer having low solubility and selectively precipitating.

The method for separating and purifying a bridged indenyl compound of the present invention can be used for a bridged indenyl compound crosslinked with a silicon atom or a germanium atom, and the bridged indenyl compound can be purified with a high yield.
Further, the purification method of the present invention is economical by a simple and easy technique, and thus can be effectively used for industrialization.

1. Cross-linked indenyl compound The cross-linked indenyl compound to be purified in the present invention is a compound represented by the following formula (I).

[R ¹ and R ¹¹ (positions of 2-, 2′-) may be the same or different from each other, and may have a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a substituent. These are a good aryl group having 6 to 30 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an amino group having an alkyl group having 1 to 6 carbon atoms, and a 5- to 10-membered heterocyclic substituent.
R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a carbon number. An alkenyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 30 carbon atoms which may have a substituent, and a 5- to 10-membered heterocyclic substituent.
Q is a divalent silylene group having a substituent or a divalent germylene group having a substituent, and represents a group that bridges two indenyl rings. ]

  Examples of the alkyl group having 1 to 10 carbon atoms include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, n-pentyl, and n-hexyl. , Cyclopropyl, cyclopentyl, cyclohexyl, n-heptyl, n-octyl and the like, preferably methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl and n-hexyl. More preferred is an alkyl group having 1 to 4 carbon atoms.

Examples of the aryl group having 6 to 30 carbon atoms which may have a substituent include phenyl, biphenylyl, naphthyl and anthracenyl groups as the basic skeleton.
Furthermore, you may have a halogen atom, an alkyl group, a silyl group, an alkoxy group etc. on those frame | skeleton.
Specifically, o-, m-, p-fluorophenyl, o-, m-, p-chlorophenyl, o-, m-, p-bromophenyl, 2,4-, 3,5-, 2,6 -, 2,5-difluorophenyl, 2,4-, 3,5-, 2,6-, 2,5-dichlorophenyl, 2,4,6-trifluorophenyl, 2,4,6-trichlorophenyl, penta Fluorophenyl, pentachlorophenyl, 4-fluoronaphthyl, 4-chloronaphthyl, 2,4-difluoronaphthyl, heptafluoro-1-naphthyl, heptachloro-1-naphthyl, o-, m-, p-trifluoromethylphenyl, o -, M-, p-trichloromethylphenyl, 2,4-, 3,5-, 2,6-, 2,5-bis (trifluoromethyl) phenyl, 2,4-, 3,5-, 2, 6-, 2,5-bis Halogenated aryl groups such as trichloromethyl) phenyl, 2,4,6-tris (trifluoromethyl) phenyl, 4-trifluoromethylnaphthyl, 4-trichloromethylnaphthyl, 2,4-bis (trifluoromethyl) naphthyl , Tolyl, dimethylphenyl, ethylphenyl, trimethylphenyl, methylbiphenylyl, methylnaphthyl, etc., alkyl-substituted aryl groups, 2-, 3-, 4-trimethylsilylphenyl, 2-, 3-, 4-t-butyldimethylsilyl Phenyl, 2-, 3-, 4-diphenylmethylsilylphenyl, 2-, 3-, 4-dimethylphenylsilylphenyl, trimethylsilyltolyl, 4-trimethylsilyl-1-naphthyl, 6-trimethylsilyl-1-naphthyl, 4-trimethylsilyl 2-naphthyl, 6- Aryl groups having a substituted silyl group such as limethylsilyl-2-naphthyl, 4-t-butyldimethylsilyl-2-naphthyl, 6-t-butyldimethylsilyl-2-naphthyl, alkoxy groups such as methoxyphenyl and phenoxyphenyl An aryl group having

  Examples of the alkenyl group having 2 to 10 carbon atoms include vinyl, propenyl, allyl, butenyl, cyclohexenyl and the like.

  Examples of the alkoxy group having 1 to 6 carbon atoms include methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, tert-butoxy, phenoxy and the like.

  Examples of the amino group having an alkyl group having 1 to 6 carbon atoms include dimethylamino, diethylamino, diisopropylamino, pyrrolidinyl and the like.

Examples of 5- to 10-membered heterocyclic substituents include pyridine ring, thiophene ring, furan ring, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, triazole ring, pyrazole ring, furazane. Ring, thiadiazole ring, oxadiazole ring, pyridazine ring, pyrimidine ring, pyrazine ring, indole ring, isoindole ring, indazole ring, chromene ring, quinoline ring, isoquinoline ring, cinnoline ring, quinazoline ring, quinoxaline ring, naphthyridine ring, Phthalazine ring, purine ring, pteridine ring, thienofuran ring, imidazothiazole ring, benzofuran ring, benzothiophene ring, benzoxazole ring, benzthiazole ring, benzthiadiazole ring, benzimidazole ring, imidazo [1,2-a] pi Jin ring, pyrrolopyridine ring, pyrrolopyrimidine ring, and a pyridopyrimidine ring.
Preferably, a monovalent group derived from a pyridine ring, a thiophene ring, a furan ring, a quinoline ring, a quinazoline ring, or a benzofuran ring by removing one hydrogen atom at any position can be exemplified, and further a substituent can be added to them. You may have.
Among them, preferred are a furyl group, a thienyl group, a furyl group having a substituent, or a thienyl group having a substituent, and in particular, 2-furyl, 2- (5-methylfuryl), 2-thienyl, 2- ( 5-methylthienyl) group is preferred.

Q is a divalent silylene group having a substituent or a divalent germylene group having a substituent. Specific examples of the silylene group having a substituent include methylsilylene, dimethylsilylene, diethylsilylene, and di-n-propylsilylene. Alkylsilylene groups such as di-propylsilylene and dicyclohexylsilylene, alkyl (aryl) silylene groups such as methyl (phenyl) silylene and methyl (tolyl) silylene, arylsilylene groups such as diphenylsilylene, and alkylsilylene groups such as tetramethyldisilylene Examples include oligosilylene groups.
Among the examples of the silylene group, a bridging group in which a silicon atom is substituted with a germanium atom may be used. Specific examples of the group in which the crosslinking group portion has a cyclic structure include a silafluorene group and a silacycloalkylene group.

R ¹ and R ¹¹ are preferably a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a 5- to 10-membered heterocyclic substituent, such as a hydrogen atom, methyl, 2-furyl, 2- (5-methylfuryl). ), 2-thienyl and 2- (5-methylthienyl) groups are more preferable, and 2-furyl, 2- (5-methylfuryl), 2-thienyl and 2- (5-methylthienyl) groups are particularly preferable.
One or both of R ¹ and R ¹¹ are preferably either a furyl group, a thienyl group, a furyl group having a substituent, or a thienyl group having a substituent.
R ² , R ⁶ , R ¹² and R ¹⁶ are preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and particularly preferably a hydrogen atom.

As R < ³ > and R < ¹³ >, the C6-C30 aryl group which may have a substituent is preferable.
One or both of R ³ and R ¹³ are preferably either an aryl group having 6 to 30 carbon atoms which may have a substituent or a 5- to 10-membered heterocyclic substituent.

R ⁴ , R ⁵ , R ¹⁴ and R ¹⁵ are preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, particularly preferably a hydrogen atom or a methyl group.

Specific examples of the crosslinked indenyl compound represented by the formula (1) are shown below.
(1) Bis (4-phenyl-1-indenyl) dimethylsilane (2) Bis {4- (4-biphenylyl) -1-indenyl} dimethylsilane (3) Bis {4- (2-naphthyl) -1-indenyl } Dimethylsilane (4) bis {4- (4-chlorophenyl) -1-indenyl} dimethylsilane (5) bis {4- (4-methylphenyl) -1-indenyl} dimethylsilane (6) bis {4- ( 4-Isopropylphenyl) -1-indenyl} dimethylsilane (7) bis {4- (4-t-butylphenyl) -1-indenyl} dimethylsilane (8) bis {4- (4-trimethylsilylphenyl) -1- Indenyl} dimethylsilane (9) bis {4- (2-chloro-4-biphenylyl) -1-indenyl} dimethylsilane (10) bis {4- (2-methyl) -4-biphenylyl) -1-indenyl} dimethylsilane (11) bis {4- (2-chloro-4-biphenylyl) -1-indenyl} dimethylsilane (12) bis {4- (4-chloro-2-naphthyl) ) -1-Indenyl} dimethylsilane

(13) Bis (2-methyl-4-phenyl-1-indenyl) dimethylsilane (14) Bis {2-methyl-4- (4-biphenylyl) -1-indenyl} dimethylsilane (15) Bis {2-methyl -4- (2-Naphtyl) -1-indenyl} dimethylsilane (16) bis {2-methyl-4- (4-chlorophenyl) -1-indenyl} dimethylsilane (17) bis {2-methyl-4- ( 4-methylphenyl) -1-indenyl} dimethylsilane (18) bis {2-methyl-4- (4-isopropylphenyl) -1-indenyl} dimethylsilane (19) bis {2-methyl-4- (4- t-butylphenyl) -1-indenyl} dimethylsilane (20) bis {2-methyl-4- (4-trimethylsilylphenyl) -1-indenyl} dimethylsilane (21) Bis {2-methyl-4- (2-chloro-4-biphenylyl) -1-indenyl} dimethylsilane (22) Bis {2-methyl-4- (2-methyl-4-biphenylyl) -1 -Indenyl} dimethylsilane (23) bis {2-methyl-4- (2-chloro-4-biphenylyl) -1-indenyl} dimethylsilane (24) bis {2-methyl-4- (4-chloro-2-) Naphthyl) -1-indenyl} dimethylsilane

(25) bis (2-ethyl-4-phenyl-1-indenyl) dimethylsilane (26) bis {2-ethyl-4- (4-biphenylyl) -1-indenyl} dimethylsilane (27) bis {2-ethyl -4- (2-naphthyl) -1-indenyl} dimethylsilane

(28) Bis (2- (5-methyl-2-furyl) -4-phenyl-1-indenyl) dimethylsilane (29) Bis {2- (5-methyl-2-furyl) -4- (4-biphenylyl) ) -1-Indenyl} dimethylsilane (30) bis {2- (5-methyl-2-furyl) -4- (2-naphthyl) -1-indenyl} dimethylsilane (31) bis {2- (5-methyl) -2-furyl) -4- (4-chlorophenyl) -1-indenyl} dimethylsilane (32) bis {2- (5-methyl-2-furyl) -4- (4-methylphenyl) -1-indenyl} Dimethylsilane (33) bis {2- (5-methyl-2-furyl) -4- (4-isopropylphenyl) -1-indenyl} dimethylsilane (34) bis {2- (5-methyl-2-furyl) -4- (4-t Butylphenyl) -1-indenyl} dimethylsilane (35) bis {2- (5-methyl-2-furyl) -4- (4-trimethylsilylphenyl) -1-indenyl} dimethylsilane (36) bis {2- ( 5-methyl-2-furyl) -4- (2-chloro-4-biphenylyl) -1-indenyl} dimethylsilane (37) bis {2- (5-methyl-2-furyl) -4- (2-methyl) -4-biphenylyl) -1-indenyl} dimethylsilane (38) bis {2- (5-methyl-2-furyl) -4- (2-chloro-4-biphenylyl) -1-indenyl} dimethylsilane (39) Bis {2- (5-methyl-2-furyl) -4- (4-chloro-2-naphthyl) -1-indenyl} dimethylsilane (40) bis {2- (5-methyl-2-furyl) -4 − 4-methoxyphenyl) -1-indenyl} dimethylsilane (41) Bis {2- (5-methyl-2-furyl) -4- (4-dimethylaminophenyl) -1-indenyl} dimethylsilane

(42) Bis (2- (5-methyl-2-furyl) -4-phenyl-5-methyl-1-indenyl) dimethylsilane (43) Bis {2- (5-methyl-2-furyl) -4- (4-Biphenylyl) -5-methyl-1-indenyl} dimethylsilane (44) bis {2- (5-methyl-2-furyl) -4- (2-naphthyl) -5-methyl-1-indenyl} dimethyl Silane (45) bis (2- (5-methyl-2-furyl) -4-phenyl-5-methyl-1-indenyl) methylphenylsilane

(46) Bis (2- (5-methyl-2-furyl) -4-phenyl-5-methyl-1-indenyl) silafluorene (47) Bis (2- (5-methyl-2-furyl) -4- Examples thereof include phenyl-5-methyl-1-indenyl) dimethylgermane.

  In the above example, germane can be exemplified instead of silane, and as the bridged indenyl compound, a symmetrical bridged bisindenyl compound having the same substituent on the corresponding carbon of the indenyl ring is mentioned, but it has different substituents. An asymmetric bridged indenyl compound may be used.

2. Process (1)
In this invention, it goes through the process of making the compound of Formula (1) react with a base compound.
(A) Base compound The base compound that is the subject of the present invention is not particularly limited as long as it can react with the crosslinked indenyl compound of the formula (1). It is desirable to be. The pKa of the conjugate acid of the compound having a cyclopentadiene structure is approximately 17 to 22 (value measured in DMSO). Journal of Organic Chemistry, 1980, 45, 3,325, the American Chemical Society, 1983, 105, 6,188. For this reason, if pKa which the conjugate acid of this base compound shows is 25 or more, the deprotonation reaction of a bridged indenyl compound can fully be advanced.
More preferable specific examples of the base compound include alkali metal alkoxides, and sodium methoxide, sodium ethoxide, sodium t-butoxide, potassium methoxide, potassium ethoxide, and potassium t-butoxide are particularly preferable.
The amount of the base compound used is usually 0.01 to 0.9 times mol, preferably 0.01 to 0.5 times mol, particularly preferably 0.01 to 0.1 times mol, based on the crosslinked indenyl compound. .

(B) Solvent
The solvent used in this reaction is not limited as long as it dissolves the base compound. Specific examples thereof include toluene, xylene, mesitylene, ethylbenzene, propylbenzene, cumene, butylbenzene, isobutylbenzene, and t-butyl. Alkyl-substituted aromatic hydrocarbons such as benzene, pentylbenzene, hexylbenzene, such as fluorobenzene, difluorobenzene, trifluorobenzene, tetrafluorobenzene, pentafluorobenzene, hexafluorobenzene, chlorobenzene, dichlorobenzene, trichlorobenzene, tetrachlorobenzene , Pentachlorobenzene, hexachlorobenzene, bromobenzene, dibromobenzene, tribromobenzene, tetrabromobenzene, pentabromobenzene, hexabromine Halogen-substituted aromatic carbonization such as benzene, iodobromobenzene, diiodobenzene, triiodobenzene, tetraiodobenzene, pentaiodobenzene, hexaiodobenzene, chloronaphthalene, dichloronaphthalene, fluorotoluene, chlorotoluene, bromotoluene, iodotoluene Hydrogens such as anisole, ethoxybenzene, propyloxybenzene, butoxybenzene, pentyloxybenzene, hexyloxybenzene and other alkoxy-substituted aromatic hydrocarbons such as methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol , Nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecane And alcohols such as benzyl alcohol, for example, ketones such as acetone, methyl ethyl ketone, diethyl ketone, hexanone, cyclohexyl acetone, acetophenone, propiophenone, acetoin, such as dimethyl ether, methyl ethyl ether, diethyl ether, diisopropyl ether, t- Examples thereof include organic solvents such as butyl methyl ether, tetrahydrofuran, tetrahydropyran, 1,4-dioxane, and ethers such as cyclopentylphenyl ether.

These solvents are appropriately selected depending on the type of reaction substrate, reaction temperature, target reaction time, and the like, and may be used alone or in combination of two or more.
Among these, alkyl-substituted aromatic hydrocarbons, ethers, and alcohols are preferable, and diethyl ether, diisopropyl ether, tetrahydrofuran, methanol, ethanol, and propanol are more preferable, and methanol, ethanol, and 2-propanol are particularly preferable. Is preferred.

(C) Reaction The temperature at which the reaction is carried out can be arbitrarily selected within the range of the boiling point of the solvent system used from a low temperature (for example, the freezing point of the solvent system) (in the mixed solvent system, the boiling point indicated by the solvent composition to be reacted).
In the reaction method of the present invention, the concentration of the reaction substrate to be used with respect to the solvent can be arbitrarily selected within the range of dissolution.
The mixture containing a bridged indenyl compound used for the reaction includes a bridged indenyl compound (including a case of a mixture of target compounds and isomers) obtained by synthesizing the bridged indenyl compound, a by-product, an unreacted substrate, and the like. It is a mixture containing.
By the reaction between the bridged indenyl compound and the base compound, the bridged indenyl compound is selectively and preferentially changed into a compound insoluble in the solvent (including the case of isomerization).

4). Step (2)
In this step, the crosslinked indenyl compound is isolated from the reaction mixture obtained in step (1) by recrystallization or solid-liquid separation.
(A) Recrystallization Basically, recrystallization is performed by a usual method. Although it does not specifically limit as an organic solvent used for recrystallization, Specifically, toluene, pentane, hexane, heptane, xylene, tetrahydrofuran (THF), dimethoxyethane (DME), diethyl ether, diisopropyl ether, methanol, Ethanol, etc. can be mentioned, and a mixture thereof can also be used.
A solution of the obtained reaction mixture is heated as necessary and dissolved in a solvent, and then the solvent is concentrated by evaporation or cooled, whereby a desired crosslinked indenyl compound is precipitated and can be separated.
Crystallization is carried out at −78 ° C. to 200 ° C., preferably −30 ° C. to 110 ° C., particularly preferably −15 ° C. to 30 ° C.

(B) Solid-liquid separation Separation after precipitation can be solid-liquid separated. In some cases, a desired crosslinked indenyl compound may precipitate during the reaction in step (1) and can be separated as it is. In that case, purification is possible without performing the recrystallization described above. For solid-liquid separation, known means such as decantation and filtration can be performed.

EXAMPLES Hereinafter, although this invention is demonstrated still in detail based on an Example, in order to clarify this invention and its effect more clearly, the following Example performs the illustration of preferable implementation.
In the following examples, all reaction steps were carried out under a purified nitrogen atmosphere, and the solvent was dehydrated with molecular sieve MS-4A, then bubbled with purified nitrogen and degassed before use.

[Example 1]
The effect of the present invention was verified through synthesis and purification of bis {2- (5-methyl-2-furyl) -4- (4-isopropylphenyl) -1-indenyl} dimethylsilane.
1-1. Synthesis of bridged indenyl compound Crude products of bis {2- (5-methyl-2-furyl) -4- (4-isopropylphenyl) -1-indenyl} dimethylsilane are disclosed in Examples of JP-A-2009-299045. 11 was synthesized with reference to the method described in 11.
To a 500 ml glass reaction vessel, 12.9 g (41 mmol) of 2- (5-methyl-2-furyl) -4- (4-i-propylphenyl) -indene and 150 ml of THF were added, and the mixture was added with a dry ice-methanol bath. Cooled to 40 ° C. To this, 27 ml (45 mmol) of a 1.67 mol / L n-butyllithium-hexane solution was added dropwise and stirred as it was for 3 hours. The mixture was cooled again to −40 ° C., 0.33 ml (4.1 mmol) of 1-methylimidazole and 2.6 g (20 mmol) of dimethyldichlorosilane were sequentially added, and the mixture was stirred for 2 hours while gradually returning to room temperature. Distilled water was added to the reaction solution, transferred to a separatory funnel and washed with brine until neutral, and sodium sulfate was added to dry the reaction solution.
Sodium sulfate was filtered and the solvent was distilled off under reduced pressure to obtain a crude product of bis {2- (5-methyl-2-furyl) -4- (4-isopropylphenyl) -1-indenyl} dimethylsilane. . The isomer ratio in this crude product was 50:50.

1-2. Purification by reaction with base To the obtained crude product, 300 ml of ethanol and 80 mg (0.7 mmol) of t-butoxypotassium were added and stirred overnight at room temperature (step (1)).
The precipitate is then filtered (step (2)) and washed with ethanol to give pure bis (2- (5-methyl-2-furyl) -4- (4-i-propylphenyl) -indenyl). 12.1 g (yield 86%) of colorless crystals of dimethylsilane were obtained. The isomer ratio of the obtained product was approximately 100: 0.

[Example 2]
The effect of the present invention was verified through synthesis and purification of bis {2- (5-methyl-2-furyl) -4- (3,5-dimethylphenyl) -1-indenyl} dimethylsilane.
2-1. Synthesis of cross-linked indenyl compound To a 200 ml glass reaction vessel, 1.62 g (5.2 mmol) of 2- (5-methyl-2-furyl) -4- (3,5-dimethylphenyl) -indene and 35 ml of THF were added, Cooled to -5 ° C. To this, 3.2 ml (5.2 mmol) of a 1.63 mol / L n-butyllithium-hexane solution was added dropwise and stirred at room temperature for 3 hours. The mixture was cooled again to −5 ° C., 4.2 l (0.05 mmol) of 1-methylimidazole and 0.31 ml (2.6 mmol) of dimethyldichlorosilane were sequentially added, and the mixture was stirred for 30 minutes while gradually returning to room temperature. Distilled water was added to the reaction solution, transferred to a separatory funnel and washed with brine until neutral, and sodium sulfate was added to dry the reaction solution.
Sodium sulfate was filtered and the solvent was distilled off under reduced pressure to obtain a crude product of bis {2- (5-methyl-2-furyl) -4- (3,5-dimethylphenyl) -1-indenyl} dimethylsilane. It was. The isomer ratio in this crude product was 50:50.

2-2. Purification by reaction with base To the obtained crude product (1.1 g, 1.59 mmol), 20 ml of ethanol and 5.3 mg (0.048 mmol) of potassium t-butoxy were added and stirred overnight at room temperature (step (1 )). The precipitate is then filtered (step (2)) and washed with ethanol to give pure bis (2- (5-methyl-2-furyl) -4- (3,5-dimethylphenyl) -indenyl). 0.69 g (yield 63%) of colorless crystals of dimethylsilane was obtained. The isomer ratio of the obtained product was approximately 63:37.

[Comparative Example 1]
Recrystallization without the reaction of bis {2- (5-methyl-2-furyl) -4- (4-isopropylphenyl) -1-indenyl} dimethylsilane with a base In the same manner as in Example 1, bis {2 A crude product of-(5-methyl-2-furyl) -4- (4-isopropylphenyl) -1-indenyl} dimethylsilane was synthesized.
When this crude product was recrystallized from hexane (30 ml), colorless crystals of bis {2- (5-methyl-2-furyl) -4- (4-isopropylphenyl) -1-indenyl} dimethylsilane 2 0.0 g (22% yield) was obtained.

[Comparative Example 2]
Recrystallization without the reaction of bis {2- (5-methyl-2-furyl) -4- (3,5-dimethylphenyl) -1-indenyl} dimethylsilane with a base In the same manner as in Example 2, A crude product of {2- (5-methyl-2-furyl) -4- (3,5-dimethylphenyl) -1-indenyl} dimethylsilane was synthesized.
This crude product (0.69 g) was recrystallized from hexane (2 ml), but the target product did not precipitate and could not be isolated and purified.

[Contrast between Example and Comparative Example]
In comparison with the above Examples and Comparative Examples, the method for separating and purifying a crosslinked indenyl compound of the present invention can perform separation very effectively and obtain a desired crosslinked indenyl compound with high purity.
It has also been clarified that the present invention can be used economically advantageously by a simple and easy technique.

The present invention is very useful industrially in the production of a metallocene complex in a metallocene catalyst because it can be effectively separated and purified from a bridged indenyl compound and can be advantageously used economically.

Claims (6)

Formula is represented by the following formula (I), a mixture comprising a crosslinked indenyl compounds that exist isomers due to asymmetric carbon atoms, by operating the following steps (1) and (2), A method for purifying a bridged indenyl compound, comprising separating a compound represented by the following formula (I):

[Wherein R ¹ and R ¹¹ may be the same or different from each other, and may be a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 30 carbon atoms which may have a substituent, They are an alkoxy group having 1 to 6 carbon atoms, an amino group having an alkyl group having 1 to 6 carbon atoms, and a 5- to 10-membered heterocyclic substituent.
R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a carbon number. An alkenyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 30 carbon atoms which may have a substituent, and a 5- to 10-membered heterocyclic substituent.
Q is a divalent silylene group having a substituent or a divalent germylene group having a substituent, and represents a group that bridges two indenyl rings. ]
Step (1) Step (2) of isomerizing a compound of formula (I) in the presence of a base compound From the isomerization mixture obtained in step (1), recrystallization or solid-liquid separation yields formula (I). Isolating the represented compound The method for purifying a crosslinked indenyl compound according to claim 1, wherein the base compound is an alkali metal alkoxide. The method for purifying a crosslinked indenyl compound according to claim 1 or 2, wherein the reaction solvent used in step (1) is selected from methanol, ethanol, and 2-propanol. In the general formula (I), one or both of R ¹ and R ^{11 is} any one of a furyl group, a thienyl group, a furyl group having a substituent, or a thienyl group having a substituent. The method for purifying a crosslinked indenyl compound according to any one of claims 1 to 3. In the general formula (I), one or both of R ³ and R ¹³ are an aryl group having 6 to 30 carbon atoms which may have a substituent or a 5- to 10-membered heterocyclic substituent. The method for purifying a bridged indenyl compound according to any one of claims 1 to 4, wherein: The method for purifying a crosslinked indenyl compound according to any one of claims 1 to 5, wherein Q in the general formula (I) is a dialkylsilylene group or a dialkylgermylene group.