Method for producing 1,2-polybutadiene, and catalyst composition

Abstract

Provided are: a method for producing 1,2-polybutadiene, the method capable of producing 1,2-polybutadiene by polymerization without impairing the catalytic activity of a catalyst composition; and a catalyst composition for use in the method.　A method for producing 1,2-polybutadiene according to the present invention has a step for polymerizing 1,3-butadiene in the presence of a catalyst system, the catalyst system containing component (a) that is a salt of a transition metal, component (b) that is an aluminoxane compound, component (c) that is a phosphine compound represented by general formula (1), and component (d) that is a compound containing at least one element selected from the group consisting of nitrogen, oxygen, and sulfur. In general formula (1): R1 and R2 each represent a substituted or unsubstituted hydrocarbyl group having 6 to 30 carbon atoms; and R3 represents a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted branched alkyl group having 3 to 20 carbon atoms, or a substituted cycloalkyl group having 6 to 30 carbon atoms.

Description

Method for producing 1,2-polybutadiene and catalyst composition

[0001] The present invention relates to a method for producing 1,2-polybutadiene by polymerizing 1,3-butadiene in the presence of a specific catalyst system, and to a catalyst composition used therefor.

[0002] Syndiotactic-1,2-polybutadiene has a structure consisting of highly crystalline and amorphous regions, giving it the functionality of a thermoplastic elastomer. Furthermore, because it contains highly chemically reactive carbon-carbon double bonds in its molecule, it also possesses the functions of conventional vulcanized rubber and thermosetting resins with increased crosslinking density. In addition, due to its excellent processability, 1,2-polybutadiene is used as a modifier for other resins and thermoplastic elastomers (for example, in tire applications to improve strength) and as a polymer material for medical use.

[0003] Conventional methods for producing 1,2-polybutadiene include a method in which 1,3-butadiene is polymerized in the presence of a cis polymerization catalyst to produce cis-1,4-polybutadiene, and then 1,2-polymerization catalyst is added to this polymerization system to polymerize 1,3-butadiene to produce the final polybutadiene (see, for example, Patent Document 1), and a method in which butadiene or a conjugated diene other than butadiene is polymerized in the presence of a catalyst containing a cobalt compound and an aluminoxane (see, for example, Patent Document 2).

[0004] However, the above method for producing 1,2-polybutadiene has a problem in that the catalytic activity is low because the catalyst precursor, such as the cobalt compound used, has low solubility in organic solvents. Therefore, it is necessary to use a large amount of halogenated solvent as the polymerization solvent, which is undesirable from an environmental perspective.

[0005] Japanese Patent Publication No. 49-017667, Japanese Patent Publication No. 2006-089759

[0006] The present invention has been made based on the circumstances described above, and its object is to provide a method for producing 1,2-polybutadiene that can polymerize 1,2-polybutadiene having the desired stereoregularity without impairing the catalytic activity of the catalyst composition, and a catalyst composition used therefor.

[0007] As a result of diligent research to achieve the above objective, the present inventors have discovered that by using a specific Lewis base compound, the solubility in solvents of a complex of a transition metal salt coordinated to a phosphine compound can be improved, and moreover, the Lewis base compound does not inhibit polymerization, and therefore, 1,2-polybutadiene with the desired stereoregularity can be selectively synthesized, thus completing the present invention.

[0008] The present invention provides a method for producing 1,2-polybutadiene, characterized by comprising the step of polymerizing 1,3-butadiene in the presence of a catalyst system containing (a) a salt of a transition metal, (b) an aluminoxane compound, (c) a phosphine compound represented by the following general formula (1), and (d) a compound containing at least one element selected from the group consisting of nitrogen, oxygen, and sulfur.

[0009]

[0010] [In the above general formula (1), R 1 and R 2 R represents a substituted or unsubstituted hydrocarbyl group having 6 to 30 carbon atoms, and may be the same or different from each other. 3 This represents a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted branched alkyl group having 3 to 20 carbon atoms, or a substituted cycloalkyl group having 6 to 30 carbon atoms.

[0011] In the method for producing 1,2-polybutadiene of the present invention, it is preferable that the transition metal constituting component (a) is cobalt, and it is particularly preferable that component (a) is a cobalt halide.

[0012] In the method for producing 1,2-polybutadiene of the present invention, it is preferable that the 1,2-polybutadiene has a 1,2-vinyl bond content of 30% by mass or more.

[0013] In the method for producing 1,2-polybutadiene of the present invention, the usage ratio of the component (c) to 1 mol of the component (a) is preferably 0.1 to 5 mol, and the usage ratio of the component (d) to 1 mol of the component (a) is preferably 0.1 to 20 mol. Also, in the method for producing 1,2-polybutadiene of the present invention, the usage ratio of the component (d) to 1 mol of the component (c) is preferably 0.02 to 200 mol.

[0014] In the method for producing 1,2-polybutadiene of the present invention, the component (d) is not particularly limited as long as it is a compound having a lone pair of electrons capable of coordinating to a transition metal salt. For example, a phosphine oxide group, a phosphine sulfide group, a phosphate group, an amino group, an amide group, an imine group, a hydroxy group, a (thio) aldehyde group, a (thio) ketone group, a (thio) carboxyl group, a thioester group (-C(=O)-S-), a thionoester group (-C(=S)-O-), a dithioester group (-C(=S)-S-), a thiocarbamide group (-NR 4 -C(=S)-NR 5 -), a xanthate group (-O-C(=S)-S-), a trithiocarbonate group (-S-C(=S)-S-), a carbamate group (-O-CO-NH-), a dithiocarbamate group (-NR 4 -C(=S)-S-), an ether group, a sulfide group, a sulfoxide group (-S(=O)-), a nitrile group (-C≡N), a urea group (-NH-CO-NH-), an azide group (-N 3 ), a nitro group (-NO 2 ), a pyridyl group, an ester group (-C(=O)-O-) selected from the group consisting of at least one functional group (where R 4 and R 5 are each independently a hydrocarbyl group having 1 to 20 carbon atoms). It is preferably included.

[0015] The catalyst composition of the present invention contains: component (a): a salt of a transition metal; component (b): an aluminoxane compound; component (c): a phosphine compound represented by the following general formula (1); and component (d): a compound containing at least one element selected from the group consisting of nitrogen, oxygen, and sulfur, and is characterized by this.

[0016]

[0017] [In the above general formula (1), R 1 and R 2 each represent a substituted or unsubstituted hydrocarbyl group having 6 to 30 carbon atoms, and may be the same as or different from each other. Further, R 3 represents a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted branched alkyl group having 3 to 20 carbon atoms, or a substituted cycloalkyl group having 6 to 30 carbon atoms. ]

[0018] In the catalyst composition of the present invention, it is preferable that the transition metal constituting the component (a) is cobalt, and it is particularly preferable that the component (a) is a halide of cobalt.

[0019] In the catalyst composition of the present invention, the usage ratio of the component (c) with respect to 1 mol of the component (a) is preferably 0.1 to 5 mol, and the usage ratio of the component (d) with respect to 1 mol of the component (a) is preferably 0.1 to 20 mol. Also, in the catalyst composition of the present invention, the usage ratio of the component (d) with respect to 1 mol of the component (c) is preferably 0. of 02 to 200 mol.

[0020] In the catalyst composition of the present invention, the component (d) is not particularly limited as long as it is a compound having a lone pair of electrons capable of coordinating to a transition metal salt. For example, a phosphine oxide group, a phosphine sulfide group, a phosphate group, an amino group, an amide group, an imine group, a hydroxy group, a (thio) aldehyde group, a (thio) ketone group, a (thio) carboxyl group, a thioester group (-C(=O)-S-), a thionoester group (-C(=S)-O-), a dithioester group (-C(=S)-S-), a thiocarbamide group (-NR 4 -C(=S)-NR 5 -), xanthate group (-O-C(=S)-S-), trithiocarbonate group (-S-C(=S)-S-), carbamate group (-O-CO-NH-), dithiocarbamate group (-NR 4 -C(=S)-S-), ether group, sulfide group, sulfoxide group (-S(=O)-), nitrile group (-C≡N), urea group (-NH-CO-NH-), azide group (-N 3 ), nitro group (-NO 2 ), a pyridyl group, an ester group (-C(=O)-O-), at least one functional group selected from the group (where R 4 and R 5 It is preferable that the following are hydrocarbyl groups having 1 to 20 carbon atoms, independently of each other.

[0021] According to the method for producing 1,2-polybutadiene and the catalyst composition of the present invention, the presence of component (d) in the catalyst composition improves the solubility in the solvent of the complex having component (a): a transition metal salt and component (c): a phosphine compound represented by the above general formula (1). Moreover, since component (d) does not inhibit polymerization, high catalytic activity is obtained in the catalyst composition, and as a result, 1,2-polybutadiene having the desired stereoregularity can be polymerized with high accuracy.

[0022] Embodiments of the present invention will be described below. In this specification, the numerical range described using "X to Y" means that the numerical value X is included as the lower limit and the numerical value Y is included as the upper limit.

[0023] The present invention provides a method for producing 1,2-polybutadiene, comprising the step of polymerizing 1,3-butadiene in the presence of a catalyst system comprising a catalyst composition (hereinafter also referred to as a "specific catalyst composition") containing (a) a transition metal salt, (b) an aluminoxane compound, (c) a phosphine compound represented by the above general formula (1) (hereinafter also referred to as a "specific phosphine compound"), and (d) a compound containing at least one element selected from the group consisting of nitrogen, oxygen, and sulfur (hereinafter also referred to as a "specific Lewis base compound"). Specifically, the specific catalyst composition is obtained by dissolving a catalyst precursor containing (a) a transition metal salt, (c) a specific phosphine compound, and (d) a specific Lewis base compound in a solvent to prepare a catalyst precursor solution, and then mixing the catalyst precursor solution with (b) an aluminoxane compound.

[0024] Component (a) of a specific catalyst composition: a transition metal salt acts as a catalyst initiator for polymerizing butadiene by being activated by component (b): an aluminoxane compound. Examples of transition metals constituting component (a) of a specific catalyst composition: manganese, iron, cobalt, nickel, etc., with cobalt being preferred among these. Furthermore, component (a): the transition metal salt is preferably a transition metal halide, nitrate, sulfate, carboxylate, diketonate, or trifluoromethanesulfonate, more preferably a transition metal halide, and particularly preferably a cobalt halide. Specific examples of component (a): the transition metal salt include cobalt chloride, cobalt bromide, cobalt iodide, cobalt fluoride, cobalt nitrate, cobalt sulfate, cobalt naphthenate, tris(2,4-pentadionato)cobalt, cobalt(II) triflate, etc.

[0025] Component (b) of a specific catalyst composition: an aluminoxane compound acts as a co-catalyst that activates component (a): a transition metal salt, thereby imparting polymerization capability. Examples of components (b) of a specific catalyst composition: an aluminoxane compound can be the compounds represented by the following general formulas (2) or (3).

[0026]

[0027]

[0028] In the aluminoxane compound represented by the above general formula (2) or the above general formula (3), R 6 ~R 11 Each of these is independently a hydrocarbon group such as a methyl group, an ethyl group, a propyl group, or a butyl group, preferably a methyl group or an ethyl group, and particularly preferably a methyl group. Also, m is an integer of 2 or more, preferably 5 or more, and more preferably 10 to 100.

[0029] (b) Components: Specific examples of aluminoxane compounds include methylaluminoxane, ethylaluminoxane, propylaluminoxane, and butylaluminoxane, with methylaluminoxane being particularly preferred.

[0030] Component (c) of a specific catalyst composition: a specific phosphine compound acts to contribute to the stereoregularity of the polymer obtained by coordinating with component (a): a transition metal salt. In the above general formula (1) representing component (c) of a specific catalyst composition: a specific phosphine compound, R 1 and R 2 These represent substituted or unsubstituted hydrocarbyl groups having 6 to 30 carbon atoms, and may be the same or different from each other.

[0031] R 1 and R 2 Preferably, the substituent is a C6-C15 alkyl group, or a substituted or unsubstituted C6-C15 aryl group. When the aryl group is substituted, examples of substituents include C1-C12 alkyl groups and C1-C12 alkoxyl groups, and if there are two or more substituents, they may be the same or different from each other. Specific examples of substituted or unsubstituted C6-C30 hydrocarbyl groups include cyclohexyl group, hexamethylcyclohexyl group, 2-isopropyl-5-methylcyclohexyl group (neomentyl group), pentamethylcyclopentyl group, 2-cyclooctylethyl group, 2-methylcyclohexyl group, 3-methylcyclohexyl group, 4-methylcyclohexyl group, 2-methoxycyclohexyl group, 3-methoxycyclohexyl group, 4-methoxycyclohexyl group, 2-phenylcyclohexyl group, 3-phenylcyclohexyl group, 4-phenylcyclohexyl group, phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 3-ethylphenyl group, 4-ethylphenyl group, 2,4-dimethylphenyl group, 3 Examples include 4-dimethylphenyl group, 3,5-dimethylphenyl group, 3,5-diethylphenyl group, 2-tert-butylphenyl group, 3-tert-butylphenyl group, 2,4,6-trimethylphenyl group, 2-isopropylphenyl group, 3-isopropylphenyl group, 4-methoxyphenyl group, 3-methoxyphenyl group, 3-methyl-5-ethylphenyl group, 3-phenylphenyl group, 3,4,5-trimethylphenyl group, 4-methoxy-3,5-dimethylphenyl group, 4-ethoxy-3,5-diethylphenyl group, 4-butoxy-3,5-dibutylphenyl group, 4-dodecylphenyl group, 1,1-diphenylethyl group, phenoxyphenyl group, naphthyl group, phenylnaphthyl group, phenanthrene group, and anthracene group. 1 and R 2 Specifically, it is preferable that all of them be phenyl groups.

[0032] Furthermore, in the above general formula (1), R 3 R represents a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted branched alkyl group having 3 to 20 carbon atoms, or a substituted cycloalkyl group having 6 to 30 carbon atoms. 3 Preferably, the substituent is a substituted or unsubstituted branched alkyl group having 4 to 15 carbon atoms, or a substituted cycloalkyl group having 6 to 15 carbon atoms. Specific examples of substituted or unsubstituted branched alkyl groups having 3 to 20 carbon atoms include isopropyl group, isobutyl group, tert-butyl group, tert-pentyl group, isopentyl group, 3-ethylpento-3-yl group, and 3-methylpento-3-yl group. Substituents for the cycloalkyl group include alkyl groups having 1 to 12 carbon atoms, alkoxyl groups having 1 to 12 carbon atoms, and alkylsilyl groups having 1 to 12 carbon atoms. If there are two or more substituents, they may be the same or different from each other. Specific examples of substituted carbon-6 to carbon-30 cycloalkyl groups include hexamethylcyclohexyl group, 2-isopropyl-5-methylcyclohexyl group (neomentyl group), pentamethylcyclopentyl group, 2-cyclooctylethyl group, 2-methylcyclohexyl group, 3-methylcyclohexyl group, 4-methylcyclohexyl group, 2-methoxycyclohexyl group, 3-methoxycyclohexyl group, 4-methoxycyclohexyl group, 2-phenylcyclohexyl group, 3-phenylcyclohexyl group, and 4-phenylcyclohexyl group. 3 Specifically, it is preferable that this is a tert-butyl group or a 2-isopropyl-5-methylcyclohexyl group (neomentyl group).

[0033] (c) Components: Specific examples of certain phosphine compounds include triphenylphosphine, tris(3-methylphenyl)phosphine, tris(3-ethylphenyl)phosphine, tris(4-methylphenyl)phosphine, tris(3,5-dimethylphenyl)phosphine, tris(3,4-dimethylphenyl)phosphine, tris(3-isopropylphenyl)phosphine, tris(3-t-butylphenyl)phosphine, tris(3,5-diethylphenyl)phosphine, tris(3-methyl-5-ethylphenyl)phosphine), tris(3-phenylphenyl)phosphine, tris(3,4,5-trimethylphenyl)phosphine, tris(4-methoxy-3,5-dimethylphenyl)phosphine, tris(4-ethoxy-3,5-diethylphenyl)phosphine, tris(4-butoxy-3,5-dibutylphenyl)phosphine, tris( Examples include 4-methoxyphenyl)phosphine, tris(3-methoxyphenylphosphine), tris(4-dodecylphenyl)phosphine, tris(4-ethylphenylphosphine), diphenylcyclohexylphosphine, diphenylisopropylphosphine, diphenylisobutylphosphine, diphenyl t-butylphosphine, diphenylcyclopentylphosphine, diphenyl(4-methylcyclohexyl)phosphine, diphenylcycloheptylphosphine, diphenylcyclooctylphosphine, tricyclohexylphosphine, isopropyldiphenylphosphine, t-butyldiphenylphosphine, cyclohexyldiphenylphosphine, cis-2-methylcyclohexyldiphenylphosphine, (S)-(+)-neomentyldiphenylphosphine, etc., with (S)-(+)-neomentyldiphenylphosphine being particularly preferred.

[0034] Component (d) of the specific catalyst composition: The specific Lewis base compound acts as a solubilizer for component (a): the transition metal salt, and does not inhibit the polymerization of 1,2-polybutadiene by acting as a catalyst poison. Component (d) of the specific catalyst composition: The specific Lewis base compound is not particularly limited as long as it is a compound having a lone pair of electrons that can coordinate to the transition metal salt, and is a compound containing at least one element selected from the group consisting of nitrogen, oxygen, and sulfur, specifically a phosphine oxide group, phosphine sulfide group, phosphoric acid group, amino group, amide group, imine group, hydroxyl group, (thio)aldehyde group, (thio)ketone group, (thio)carboxyl group, thioester group (-C(=O)-S-), thionoester group (-C(=S)-O-), dithioester group (-C(=S)-S-), thiocarbamide group (-NR 4 -C(=S)-NR 5 -), xanthate group (-O-C(=S)-S-), trithiocarbonate group (-S-C(=S)-S-), carbamate group (-O-CO-NH-), dithiocarbamate group (-NR 4 -C(=S)-S-), ether group, sulfide group, sulfoxide group (-S(=O)-), nitrile group (-C≡N), urea group (-NH-CO-NH-), azide group (-N 3 ), nitro group (-NO 2 Examples of compounds include those containing at least one functional group selected from the group consisting of a pyridyl group and an ester group (-C(=O)-O-). 4 and R 5 These are hydrocarbyl groups with 1 to 20 carbon atoms, independently of each other.

[0035] Examples of compounds containing the phosphine oxide group or phosphine sulfide group include compounds represented by the following general formula (4).

[0036]

[0037] In the above general formula (4), R 12 , R 13 and R 14These are, independently of each other, a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms. Also, Y is an oxygen atom or a sulfur atom.

[0038] Examples of compounds containing the phosphate group include those represented by the following general formula (5).

[0039]

[0040] In the above general formula (5), R 15 and R 16 These are, independently of each other, the hydroxyl group and the group "-OR" 17 (However, R 17 This is a hydrocarbyl group having 1 to 20 carbon atoms.

[0041] Note R 4 , R 5 , R 12 ~R 17 Examples of C1-C20 hydrocarbyl groups exhibiting this property include linear or branched alkyl groups with C1-C20, cycloalkyl groups with C5-C20, aryl groups with C6-C20, and aralkyl groups with C7-C20.

[0042] Examples of compounds containing the aforementioned amino group include compounds having a primary amino group with 1 to 20 carbon atoms, compounds having a linear or cyclic secondary amino group, and compounds having a linear or cyclic secondary amino group.

[0043] Examples of compounds containing the aforementioned amide group include linear or cyclic amide compounds having 1 to 20 carbon atoms.

[0044] Examples of compounds containing the hydroxyl group include linear or branched alcohol compounds having 1 to 20 carbon atoms.

[0045] The aforementioned (thio)aldehyde group, (thio)ketone group, (thio)carboxyl group, thioester group (-C(=O)-S-), thionoester group (-C(=S)-O-), dithioester group (-C(=S)-S-), thiocarbamide group (-NR 4 -C(=S)-NR 5 -), xanthate group (-O-C(=S)-S-), trithiocarbonate group (-S-C(=S)-S-), dithiocarbamate group (-NR 4 Examples of compounds containing a -C(=S)-S-) or sulfide group include ethylene sulfide, propylene sulfide, vinylphenyl sulfide, cumyldithiobenzoate (2-phenylpropane-2-yl benzodithioate), 4,4'-bis(dimethylamino)thiobenzophenone, di-tert-butyl-thioketone, carbon disulfide, 2-propyl dithiobenzoate, S-ethyl thioacetate, S-furfuryl thiopropionate, S,S-dibenzyltrithiocarbonate, and methyl thionobenzoate.

[0046] Examples of compounds containing the ether group include linear or cyclic ether compounds having 1 to 20 carbon atoms. In linear or cyclic ether compounds having 1 to 20 carbon atoms, it is more preferable that the carbon atom bonded to the oxygen atom is either a methyl group or a primary carbon atom not bonded to an electron-withdrawing group (except for the oxygen atom constituting the ether group), as this enhances the coordinating power to the transition metal related to component (a).

[0047] Examples of compounds containing the sulfoxide group (-S(=O)-) include dimethyl sulfoxide, diethyl sulfoxide, and ethyl methyl sulfoxide.

[0048] (d) Components: Preferred specific examples of certain Lewis base compounds include piperidine, 2-methyl-2-oxazoline, pyridine, acetone, N-methyl-ε-caprolactam, laurocapram, tris(2-ethylhexyl)amine, trioctylamine, N,N-diethylacetamide, 2,5-hydroxyphenyldiphenylphosphine oxide, diphenylphosphine oxide, cyclohexyldiphenylphosphine oxide, methyl(diphenyl)phosphine oxide, (2-ethylhexyl)phosphonic acid mono-2-ethylhexyl, 2-ethylhexanol, methanol, ethanol, 2-ethylhexanoic acid, triphenylphosphine sulfide, tetrahydrofuran, triphenylphosphine oxide, etc., and piperidine is particularly preferred from the viewpoint of balancing the solubility of the transition metal salt complex in the solvent and catalytic activity.

[0049] The amount of the specific catalyst composition used is preferably such that the molar ratio (BD / Al) of aluminum atoms (Al) of component (b): aluminoxane compound to 1,3-butadiene is 50 to 6,000, more preferably 100 to 4,500, and particularly preferably 200 to 2,000. When (BD / Al) is 50 or higher, it tends to be possible to obtain a product that balances catalytic activity and economic efficiency, while when it is 6,000 or lower, polymerization activity tends to be high. Furthermore, the amount of component (b): aluminoxane compound used is preferably such that the molar ratio (Al / (a) component) of aluminum atoms (Al) to 1 mole of component (a) is 4 to 300, more preferably 7.5 to 150, and particularly preferably 10 to 130. Furthermore, the amount of component (c): specific phosphine compound used is preferably such that the ratio of component (c) to 1 mole of component (a) is 0.1 to 5 moles, more preferably 0.5 to 5 moles, and particularly preferably 1 to 5 moles. Furthermore, the amount of component (d): a specific Lewis base compound used is preferably 0.02 to 200 moles of component (d) per mole of component (c), more preferably 1 to 20 moles, and particularly preferably 1 to 5 moles. Furthermore, the amount of component (d): a specific Lewis base compound used is preferably 0.1 to 20 moles of component (d) per mole of component (a), even more preferably 0.5 to 10 moles, and particularly preferably 1 to 5 moles.

[0050] For preparing a catalyst precursor solution containing (a) a transition metal salt, (c) a specific phosphine compound, and (d) a specific Lewis base compound, it is preferable to use a halogenated solvent. Examples of halogenated solvents include dichloromethane, 1,2-dichloroethane, trichloroethylene, tetrachloroethylene, 1,2-dichlorobenzene, 1,1-dichloro-1-fluoroethane, and mixtures thereof.

[0051] The amount of solvent used to prepare the catalyst precursor solution is such that the transition metal concentration of component (a), assuming it is completely dissolved in the catalyst precursor solution, is 0.01 M or higher.

[0052] The present invention provides a method for producing 1,2-polybutadiene in the presence of the above-mentioned catalyst precursor solution and a catalyst composition (polymerization solvent) containing component (b): an aluminoxane compound. An inert organic solvent is used as the polymerization solvent. Examples of inert organic solvents include aromatic hydrocarbons such as benzene, toluene, xylene, and cumene; aliphatic hydrocarbons such as n-pentane, isopentane, neopentane, n-hexane, isohexane, neohexane, n-pentane, and n-butane; alicyclic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, and cycloheptane; and mixtures thereof.

[0053] The polymerization temperature is typically -50°C to 120°C, preferably -20°C to 100°C. The polymerization reaction is preferably a continuous polymerization in which multiple groups are linked in series. The monomer concentration in the solvent is typically 5 to 50% by mass, preferably 10 to 35% by mass. Furthermore, in order to produce 1,2-polybutadiene, care must be taken to minimize the inclusion of deactivating compounds such as oxygen, water, or carbon dioxide in the polymerization system, so as not to deactivate the catalyst and polymer.

[0054] In addition, in the method for producing 1,2-polybutadiene of the present invention, conjugated dienes other than 1,3-butadiene can also be used in combination in amounts of 10% or less. Examples of conjugated dienes include 4-alkyl-substituted-1,3-butadiene and 2-alkyl-substituted-1,3-butadiene. Among these, examples of 4-alkyl-substituted-1,3-butadiene include 1,3-pentadiene, 1,3-hexadiene, 1,3-heptadiene, 1,3-octadiene, 1,3-nonadien, and 1,3-decadien. In addition, typical examples of 2-alkyl-substituted-1,3-butadienes include 2-methyl-1,3-butadiene (isoprene), 2-ethyl-1,3-butadiene, 2-propyl-1,3-butadiene, 2-isopropyl-1,3-butadiene, 2-butyl-1,3-butadiene, 2-isobutyl-1,3-butadiene, 2-amyl-1,3-butadiene, 2-isoamyl-1,3-butadiene, 2-hexyl-1,3-butadiene, 2-cyclohexyl-1,3-butadiene, 2-isohexyl-1,3-butadiene, 2-heptyl-1,3-butadiene, 2-isoheptyl-1,3-butadiene, 2-octyl-1,3-butadiene, and 2-isooctyl-1,3-butadiene. Among these conjugated dienes, preferred conjugated dienes used in combination with 1,3-butadiene include isoprene and 1,3-pentadiene.

[0055] Once the polymerization reaction has progressed to the desired stage, the reaction mixture can be mixed with polymerization inhibitors such as alcohol, antioxidants, UV absorbers, etc. Then, the polymer produced can be separated, washed, and dried according to a conventional method to obtain the desired 1,2-polybutadiene.

[0056] [Product] The 1,2-polybutadiene obtained by the above manufacturing method has a 1,2-vinyl bond content of 30% by mass or more, preferably 35% by mass or more, more preferably 40% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more. The method for measuring the 1,2-vinyl bond content is the same as the method described in the examples below.

[0057] Furthermore, the melting point of 1,2-polybutadiene is preferably 80°C or higher, more preferably 100°C or higher, even more preferably 135°C or higher, and particularly preferably 150°C or higher. The method for measuring the melting point is the same as that described in the examples below.

[0058] The molecular weight of 1,2-polybutadiene is the number-average molecular weight on a polystyrene basis, and is typically 5.0 × 10⁻⁶. 3 ~500 x 10 3 It is preferable that it be 5.0 × 10 3 The above tends to result in superior mechanical strength, while 500 × 10 3 The following conditions tend to result in superior processability. The molecular weight can be adjusted by the ratio of aluminum atoms (Al) in component (b) of the aluminoxane compound to the transition metal atoms (M) in component (a).

[0059] Furthermore, the 1,2-polybutadiene obtained by the above manufacturing method provides sufficient strength even without crosslinking, making it suitable for non-crosslinking applications such as industrial parts and films, as well as injection molding and extrusion molding. It also exhibits excellent crosslinking reactivity, making it suitable for use in crosslinking rubber applications and as a reaction aid in vulcanization rubber. There are no particular restrictions on the processing method; mixing by melt kneading using rolls, kneaders, Banbury mixers, screw extruders, feeder-ruder extruders, etc., commonly used in resin and rubber processing, is possible. Moreover, the 1,2-polybutadiene obtained in this way is suitable as a modifier for other thermoplastic elastomers and resins. Specific applications of the 1,2-polybutadiene obtained in this way include various film materials, shoe soles, tire materials, and medical polymer materials.

[0060] The following describes specific embodiments of the present invention, but the present invention is not limited to these embodiments. In the embodiments, "parts" and "%" are based on mass unless otherwise specified.

[0061] Furthermore, various measurements and evaluations in the examples were performed using the following methods. The solid content concentration ratio was measured when polymerization was carried out under conditions where the polymerization conversion rate was 90% or more, and expressed as an index with Example 1 set to 100. To measure the solid content concentration, a sample was taken into an aluminum dish whose mass had been measured in advance, the aluminum dish was heated on a hot plate at 170°C for 5 minutes, and the solid content concentration in the sample was determined from the mass before and after heating. The vinyl bond content (1,2-bond content) and cis bond content (cis-1,4-bond content) of 1,2-polybutadiene were determined by infrared absorption spectroscopy (Morello method). The number-average molecular weight (Mn) was measured using gel permeation chromatography (GPC) at 135°C with o-dichlorobenzene as the solvent, and the polystyrene equivalent value was measured. The melting point was determined by the ASTM method using a DSC analyzer. The temperature at which the endothermic peak showed the minimum value was defined as the melting point.

[0062] [Example 1] <Preparation of catalyst precursor solution> In a dry nitrogen atmosphere, 13 mg of cobalt chloride, 32 mg of (S)-(+)-neomentyldiphenylphosphine, and 10 μl of piperidine were added to a sealed glass container, and then 10 ml of deoxygenated and dehydrated dichloromethane was added. The mixture was stirred overnight at room temperature to prepare catalyst precursor solution [1]. The supernatant solution of catalyst precursor solution [1] was used in the polymerization of 1,3-butadiene described later, and the solubility of the catalyst precursor was evaluated by drying the undissolved components and measuring their mass. The results are shown in Table 1. In Table 1, for "Solubleness of the catalyst precursor," the mass of undissolved components was evaluated as follows: "A" if it was 5% or less relative to the total amount of (a) component: transition metal salt, (c) component: specific phosphine compound, and (d) component: specific Lewis base compound used; "B" if it was more than 5% but 10% or less; "C" if it was more than 10% but 12% or less; and "D" if it was more than 12%. If the evaluation is "A" or "B", it can be determined that the catalyst precursor has high solubility.

[0063] <Polymerization of 1,3-Butadiene> In a 300 ml pressure bottle, 14 g of 1,3-butadiene (BD) and 109 g of cyclohexane (S / M = 8.0) were placed. 0.84 ml of the supernatant solution of the catalyst precursor solution [1] and a 1.0% methylaluminoxane (as Al atoms) toluene solution were added to achieve a BD / Al (molar ratio) of 250. Polymerization was carried out in a 75°C constant temperature water bath for 90 minutes. The reaction was stopped by adding a small amount of methanol as a stopper. Next, 0.3 parts of 2,6-di-t-butyl-p-cresol were added per 100 parts of polymer, and the mixture was heated on a hot plate to remove the solvent and obtain the polymer. The polymerization conversion rate was determined from the yield. The results are shown in Table 1.

[0064] [Examples 2-33 and Comparative Examples 1-8] Catalyst precursor solutions were prepared in the same manner as in Example 1, according to the conditions in Tables 1-5 below. Polymerization of 1,3-butadiene was then carried out using these catalyst precursor solutions in the same manner as in Example 1. In addition, the solubility of the catalyst precursor was evaluated by measuring the undissolved components of the catalyst precursor solution, in the same manner as in Example 1. The results are shown in Tables 1-5.

[0065] In Tables 1 to 5 below, the abbreviations for the compounds are as follows: • CoCl 2 : Cobalt chloride (CoBr) 2 Cobalt bromide NMDPP: (S)-(+)-neomenthyldiphenylphosphine TPP: Triphenylphosphine CHDPP: Cyclohexyldiphenylphosphine MeCHDPP: cis-2-methylcyclohexyldiphenylphosphine iPrDPP: Isopropyldiphenylphosphine tBuDPP: t-butyldiphenylphosphine

[0066]

[0067]

[0068]

[0069]

[0070]

[0071] By comparing Comparative Example 1 with Examples 1-16, Comparative Example 2 with Example 17, Comparative Example 3 with Examples 18,19, Comparative Example 4 with Examples 20,21, Comparative Example 5 with Examples 22,23, Comparative Example 6 with Examples 24,25, and Comparative Example 7 with Examples 26,27, as shown in Tables 1-4, it was confirmed that catalyst compositions containing (a) component: transition metal salt, (b) component: aluminoxane compound, (c) component: specific phosphine compound, and (d) component: specific Lewis base compound exhibit high solubility of the catalyst precursor in the solvent. As a result, when 1,3-butadiene is polymerized in the presence of the catalyst system of the catalyst composition, high catalytic activity (monomer conversion rate) can be obtained without impairing the stereoregularity properties of the polymer (1,2-vinyl bond content of 30% by mass or more). On the other hand, in Comparative Examples 1 to 7, which did not use component (d): a specific Lewis base compound, the solubility of the catalyst precursor was lower, and therefore the catalytic activity (monomer conversion rate) was lower, compared to the corresponding examples that used the same component (a): a transition metal salt and component (c): a specific phosphine compound.

[0072] Furthermore, as shown in Tables 3 to 5, the solubility of the catalyst precursor in the solvent can be increased regardless of the type or amount of the specific phosphine compound. As a result, it was confirmed that when 1,3-butadiene is polymerized in the presence of the catalyst system of this catalyst composition, high catalytic activity (monomer conversion rate) can be obtained without impairing the stereoregularity properties of the polymer (1,2-vinyl bond content of 30% by mass or more). In Comparative Example 8, it was confirmed that the polymer did not sufficiently acquire the desired stereoregularity properties because component (c): the specific phosphine compound was not used.

Claims

1. A method for producing 1,2-polybutadiene, characterized by comprising the step of polymerizing 1,3-butadiene in the presence of a catalyst system containing (a) a salt of a transition metal, (b) an aluminoxane compound, (c) a phosphine compound represented by the following general formula (1), and (d) a compound containing at least one element selected from the group consisting of nitrogen, oxygen, and sulfur. [In the above general formula (1), R 1 and R 2 R represents a substituted or unsubstituted hydrocarbyl group having 6 to 30 carbon atoms, and may be the same or different from each other. 3 This represents a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted branched alkyl group having 3 to 20 carbon atoms, or a substituted cycloalkyl group having 6 to 30 carbon atoms.

2. The method for producing 1,2-polybutadiene according to claim 1, characterized in that the transition metal constituting component (a) is cobalt.

3. The method for producing 1,2-polybutadiene according to claim 2, characterized in that the component (a) is a cobalt halide.

4. The method for producing 1,2-polybutadiene according to claim 1, characterized in that the 1,2-polybutadiene has a 1,2-vinyl bond content of 30% by mass or more.

5. The method for producing 1,2-polybutadiene according to claim 1, characterized in that the ratio of component (c) used to 1 mole of component (a) is 0.1 to 5 moles, and the ratio of component (d) used to 1 mole of component (a) is 0.1 to 20 moles.

6. The method for producing 1,2-polybutadiene according to claim 1, characterized in that the ratio of component (d) used to 1 mole of component (c) is 0.02 to 200 moles.

7. The component (d) is a phosphine oxide group, a phosphine sulfide group, a phosphoric acid group, an amino group, an amide group, an imine group, a hydroxy group, a (thio) aldehyde group, a (thio) ketone group, a (thio) carboxyl group, a thioester group (—C(═O)—S—), a thionoester group (—C(═S)—O—), a dithioester group (—C(═S)—S—), a thiocarbamide group (—NR 4 —C(═S)—NR 5 —), a xanthate group (—O—C(═S)—S—), a trithiocarbonate group (—S—C(═S)—S—), a carbamate group (—O—CO—NH—), a dithiocarbamate group (—NR 4 —C(═S)—S—), an ether group, a sulfide group, a sulfoxide group (—S(═O)—), a nitrile group (—C≡N), a urea group (—NH—CO—NH—), an azide group (—N 3 ), a nitro group (—NO 2 ), a pyridyl group, an ester group (—C(═O)—O—), and at least one functional group selected from the group consisting of these (however, R 4 and R 5 are each independently a hydrocarbyl group having 1 to 20 carbon atoms). The method for producing 1,2-polybutadiene according to claim 1, characterized by comprising this.

8. A catalyst composition characterized by containing (a) a salt of a transition metal, (b) an aluminoxane compound, (c) a phosphine compound represented by the following general formula (1), and (d) a compound containing at least one element selected from the group consisting of nitrogen, oxygen, and sulfur. [In the above general formula (1), R 1 and R 2 R represents a substituted or unsubstituted hydrocarbyl group having 6 to 30 carbon atoms, and may be the same or different from each other. 3 This represents a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted branched alkyl group having 3 to 20 carbon atoms, or a substituted cycloalkyl group having 6 to 30 carbon atoms.

9. The catalyst composition according to claim 8, characterized in that the transition metal constituting component (a) is cobalt.

10. The catalyst composition according to claim 9, characterized in that the component (a) is a cobalt halide.

11. The catalyst composition according to claim 8, characterized in that the ratio of component (c) used to 1 mole of component (a) is 0.1 to 5 moles, and the ratio of component (d) used to 1 mole of component (a) is 0.1 to 20 moles.

12. The catalyst composition according to claim 8, characterized in that the ratio of component (d) used to 1 mole of component (c) is 0.02 to 200 moles.

13. The above-mentioned component (d) is a phosphine oxide group, phosphine sulfide group, phosphate group, amino group, amide group, imine group, hydroxyl group, (thio)aldehyde group, (thio)ketone group, (thio)carboxyl group, thioester group (-C(=O)-S-), thionoester group (-C(=S)-O-), dithioester group (-C(=S)-S-), thiocarbamide group (-NR 4 -C(=S)-NR 5 -), xanthate group (-O-C(=S)-S-), trithiocarbonate group (-S-C(=S)-S-), carbamate group (-O-CO-NH-), dithiocarbamate group (-NR 4 -C(=S)-S-), ether group, sulfide group, sulfoxide group (-S(=O)-), nitrile group (-C≡N), urea group (-NH-CO-NH-), azide group (-N 3 ), nitro group (-NO 2 ), a pyridyl group, an ester group (-C(=O)-O-), at least one functional group selected from the group (where R 4 and R 5 The catalyst composition according to claim 8, characterized by comprising: ) which are independently hydrocarbyl groups having 1 to 20 carbon atoms.

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