A process for the polymerization of conjugated dienes and conjugated diene polymers prepared by the process

Abstract

This invention discloses a method for polymerizing conjugated dienes and the conjugated diene polymer prepared by this method. The method includes contacting at least one conjugated diene with a transition metal complex of Formula I under polymerization reaction conditions. The polymerization method according to this invention uses the transition metal complex of Formula I as a catalyst. This transition metal complex exhibits enhanced catalytic activity, effectively increasing polymer yield and polymerization efficiency. Furthermore, this transition metal complex also possesses good ability to regulate the structural units of the conjugated diene, achieving a higher content of cis-1,4-structural units.

Description

Technical Field

[0001] This invention relates to a method for polymerizing conjugated dienes, and the conjugated diene polymer prepared by this method. Background Technology

[0002] Catalyst systems for olefin rubber are crucial to olefin rubber production technology. Currently, the main catalyst systems used include nickel (Ni) based, titanium (Ti) based, cobalt (Co) based, rare earth neodymium (Nd) based, and lithium (Li) based. Among these, rare earth catalysts are the most distinctive and possess excellent comprehensive performance, producing olefin rubbers with high cis structure content, high linear structure regularity, high molecular weight, and narrow molecular weight distribution. The most commonly used rare earth catalyst is the ternary neodymium catalyst, which is a multi-center Ziegler-Natta catalyst system.

[0003] Compared to multi-center Ziegler-Natta rare earth catalytic systems, homogeneous single-center rare earth metal catalysts have higher activity, require less dosage, are easier to disperse, and are easier to control in terms of polymerization activity, polymer molecular weight, and regularity.

[0004] Finding suitable ligands for rare earth metals is a major research direction in rare earth metal organochemistry. Developing new olefin-based rubber catalysts to meet diverse application requirements is of great significance. Summary of the Invention

[0005] The purpose of this invention is to improve the activity of the catalyst in the polymerization reaction of conjugated dienes using homogeneous single-center rare earth metal catalysts, thereby improving the efficiency of the polymerization reaction and increasing the yield of polymers.

[0006] According to a first aspect of the present invention, a method for polymerizing a conjugated diene is provided, the method comprising contacting at least one conjugated diene with a transition metal complex of Formula I under polymerization reaction conditions.

[0007]

[0008] In Formula I, Ln represents a lanthanide element, scandium, or yttrium;

[0009] R1, R2, R3, R4, R5, R6, R7, R8, R9 and R 10 Whether the two are the same or different, they are each independently hydrogen, C1-C 20 Alkyl, C6-C 30 aryl or -SiR 23 R 24 R 25 R 23 R 24 and R 25 Whether they are the same or different, they are each independently hydrogen or C1-C20 Alkyl groups;

[0010] R 11 R 12 R 13 R 14 R 15 and R 16 Whether identical or different, each is independently hydrogen or a C1-C5 alkyl group;

[0011] E is O, S, or NR 17 R 17 It is a C1-C5 alkyl group or a C6-C alkyl group. 12 Aryl groups.

[0012] According to a second aspect of the present invention, the present invention provides a conjugated diene polymer prepared by the method described in the first aspect of the present invention.

[0013] The polymerization method according to the present invention uses the transition metal complex shown in Formula I as a catalyst. This transition metal complex exhibits enhanced catalytic activity, effectively increasing polymer yield and polymerization efficiency, and has industrial application value. Furthermore, this transition metal complex also has good ability to regulate the conjugated diene structural units, achieving a higher content of cis-1,4-structural units. Detailed Implementation

[0014] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0015] In this invention, the term "conjugated diene" refers to a compound whose molecular structure contains conjugated double bonds. In this invention, the conjugated diene may be selected from one or more compounds shown in Formula VI.

[0016]

[0017] In equation VI, R 20 R 21 and R 22 They may be the same or different, each selected from hydrogen and C1-C5 straight-chain or branched alkyl groups.

[0018] Specific examples of the conjugated diene may include, but are not limited to, butadiene and / or isoprene. Preferably, the conjugated diene is butadiene.

[0019] According to a first aspect of the present invention, a method for polymerizing a conjugated diene is provided, the method comprising contacting at least one conjugated diene with a transition metal complex of Formula I under polymerization reaction conditions.

[0020]

[0021] In Formula I, Ln represents a lanthanide element, scandium, or yttrium.

[0022] In this invention, the term "lanthanide elements" refers to the collective name of 15 elements from lanthanum (element 57) to lutetium (element 71) in the periodic table.

[0023] In Formula I, specific examples of Ln may include, but are not limited to: scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), or lutetium (Lu).

[0024] Preferably, in Formula I, Ln is gadolinium or scandium. More preferably, in Formula I, Ln is gadolinium.

[0025] In Equation I, R1, R2, R3, R4, R5, R6, R7, R8, R9 and R 10 Whether the two are the same or different, they are each independently hydrogen, C1-C 20 Alkyl, C6-C 30 aryl or -SiR 23 R 24 R 25 R 23 R 24 and R 25 Whether they are the same or different, they are each independently hydrogen or C1-C 20 Alkyl groups; preferably, R 23 R 24 and R 25 At least one of them is C1-C 20 Alkyl groups.

[0026] In this invention, C1-C 20 Alkyl groups include C1-C 20 Straight-chain alkyl, C3-C 20 Branched alkyl groups and C3-C 20Specific examples of cycloalkyl groups may include, but are not limited to: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, pentyl and its various isomers, hexyl and its various isomers, heptyl and its various isomers, octyl and its various isomers, nonyl and its various isomers, decyl and its various isomers, undecyl and its various isomers, dodecyl and its various isomers, tridecyl and its various isomers, tetradecyl and its various isomers, pentadecyl and its various isomers, hexadecyl and its various isomers, heptadecanyl and its various isomers, heptadecanyl and its various isomers, octadecyl and its various isomers, nonadecanyl and its various isomers, eicosyl and its various isomers, cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.

[0027] In this invention, C6-C 30 Specific examples of aryl groups may include, but are not limited to: phenyl, tolyl, ethylphenyl, propanylphenyl (wherein, the propyl group may be n-propyl or isopropyl), butylphenyl (wherein, the butyl group may be n-butyl, sec-butyl, isobutyl or tert-butyl), naphthyl, anthraceneyl or phenanthryl.

[0028] In a preferred embodiment, in Formula I, R1 and R6 are each independently a C1-C5 alkyl group, and R2, R4, R7, and R9 are each independently a C6-C5 alkyl group. 12 Aryl groups, R3, R5, R8 and R 10 All are hydrogen. In this preferred embodiment, R1 and R6 are preferably methyl, and R2, R4, R7 and R9 are preferably phenyl. In this preferred embodiment, Ln is preferably gadolinium.

[0029] In another preferred embodiment, in formula I, R1, R4, R6, and R9 are each independently C1-C1. 20 The alkyl group, R2 and R7 are each independently C6-C. 30 Aryl groups, R3, R5, R8 and R 10 All are hydrogen. In this preferred embodiment, R1, R4, R6, and R9 are each independently preferably C1-C5 alkyl groups, and R2 and R7 are each independently preferably C6-C5 alkyl groups. 12 The aryl group. More preferably, R1, R4, R6, and R9 are methyl or isopropyl, and R2 and R7 are phenyl. Even more preferably, R1 and R6 are methyl, R4 and R9 are methyl or isopropyl, and R2 and R7 are phenyl. In this preferred embodiment, Ln is preferably gadolinium.

[0030] In yet another preferred embodiment, in formula I, R1, R4, R6, and R9 are each independently C1-C1. 20 The alkyl group, R2 and R7 are each independently C6-C. 30 Aryl, R5 and R 10Both are hydrogen, and R3 and R8 are independently -SiR. 23 R 24 R 25 R 23 R 24 and R 25 Whether they are the same or different, each is independently C1-C 20 Alkyl groups. In this preferred embodiment, R1, R4, R6, and R9 are each independently preferably C1-C5 alkyl groups, and R2 and R7 are each independently preferably C6-C5 alkyl groups. 12 The aryl group, R3 and R8 are each independently preferred to be -SiR 23 R 24 R 25 R 23 R 24 and R 25 Whether the groups are the same or different, each is independently hydrogen or a C1-C5 alkyl group, and R 23 R 24 and R 25 At least one of them is a C1-C5 alkyl group. In this preferred embodiment, R1, R4, R6 and R9 are more preferably methyl, R2 and R7 are more preferably phenyl, and R3 and R8 are each more preferably -SiR. 23 R 24 R 25 R 23 R 24 and R 25 All are methyl groups. In this preferred embodiment, Ln is preferably gadolinium.

[0031] In formula I, R 11 R 12 R 13 R 14 R 15 and R 16 Whether identical or different, each is independently hydrogen or a C1-C5 alkyl group. Preferably, in formula I, R 11 R 12 R 13 R 14 R 15 and R 16 Whether the same or different, each is independently hydrogen or a C1-C5 alkyl group, and R 11 R 12 and R 13 At least one of them is a C1-C5 alkyl group, R 14 R 15 and R 16 At least one of them is a C1-C5 alkyl group. More preferably, in formula I, R 11 R 12 R 13R 14 R 15 and R 16 Whether the same or different, each is independently hydrogen or a C1-C5 alkyl group, and R 11 R 12 and R 13 At least two of them are C1-C5 alkyl groups, R 14 R 15 and R 16 At least two of them are C1-C5 alkyl groups. More preferably, in formula I, R... 11 R 12 R 13 R 14 R 15 and R 16 Whether identical or different, each is independently a C1-C5 alkyl group. More preferably, in formula I, R 11 R 12 R 13 R 14 R 15 and R 16 All are methyl groups.

[0032] In Equation I, E represents O, S, or NR. 17 R 17 It is a C1-C5 alkyl group or a C6-C alkyl group. 12 The aryl group. Preferably, in formula I, E is S.

[0033] According to the polymerization method of the present invention, the transition metal complex is preferably a complex shown in Formula II, Formula III, Formula IV, or Formula V.

[0034]

[0035] According to the polymerization method of the present invention, the transition metal complex is particularly preferably a complex represented by formula II, formula IV or formula V.

[0036] The transition metal complex can be prepared using a method comprising the following steps:

[0037] Step 1: In the presence of organolithium, the precursor compound is contacted with a heterocyclic compound selected from the compounds shown in Formula 2-2-1 and Formula 2-2-2.

[0038] Step 2: Contact the mixture obtained in Step 1 with the amine shown in Formula 2-3.

[0039] The precursor compound is selected from the compounds shown in Formula 2-1.

[0040] LnX (Equation 2-1)

[0041] In Formula 2-1, Ln is a lanthanide element, scandium or yttrium, preferably gadolinium or scandium, and more preferably gadolinium;

[0042] X is a halogen atom, such as fluorine, chlorine, bromine or iodine, preferably chlorine;

[0043]

[0044] In equations 2-2-1 and 2-2-2, R 201 R 202 R 203 R 204 and R 205 Whether the two are the same or different, they are each independently hydrogen, C1-C 20 Alkyl, C6-C 30 aryl or -SiR 23 R 24 R 25 R 23 R 24 and R 25 Whether they are the same or different, they are each independently hydrogen or C1-C 20 Alkyl groups;

[0045] In Equations 2-2-1 and 2-2-2, E is O, S, or NR. 17 R 17 It is a C1-C5 alkyl group, C6-C 12 The aryl group is preferably S;

[0046]

[0047] In Equation 2-3, R 206 R 207 R 208 R 209 R 210 and R 211 Whether identical or different, each is independently hydrogen or a C1-C5 alkyl group.

[0048] M is an alkali metal atom, such as lithium, sodium, or potassium, preferably sodium or potassium, and more preferably potassium.

[0049] In the preparation method described above, the mixture obtained in step 1 is directly used as the raw material in step 2 for reaction with the amine without separation. This eliminates the need for separation, which not only increases the complexity and cost of the process but also negatively impacts the yield of the target product due to material loss. In this method, using the mixture obtained in step 1 directly in step 2 simplifies the operation, reduces costs, and avoids adversely affecting the yield of the target product.

[0050] In the preparation method described, R in formulas 2-2-1 and 2-2-2 201 R 202 R 203 R 204 and R 205 The corresponding R1, R2, R3, R4, R5, R6, R7, R8, R9 and R in the compound shown in Formula I. 10 Specific examples are those that yield compounds represented by Formula I, and will not be elaborated upon here.

[0051] In the preparation method described, R in formula 2-3 206 R 207 R 208 R 209 R 210 and R 211 R corresponds to the compound shown in Formula I 11 R 12 R 13 R 14 R 15 and R 16 Specific examples are those that yield compounds represented by Formula I, and will not be elaborated upon here.

[0052] In the preparation method, in step 1, the precursor compound is contacted with the heterocyclic compound in the presence of organolithium, wherein the organolithium is preferably an organic monolithium compound, more preferably a compound represented by formula VIII.

[0053] R 26 Li (Formula VIII)

[0054] In equation VIII, R 26 For C1-C 10 Alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, neopentyl, hexyl (including various isomers of hexyl), heptyl (including various isomers of heptyl), octyl (including various isomers of octyl), nonyl (including various isomers of nonyl), or decyl (including various isomers of decyl).

[0055] Specific examples of the organolithium may include, but are not limited to, one or more of the following: ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, and isobutyl lithium.

[0056] Preferably, the organolithium is one or more selected from the group consisting of n-butyllithium, sec-butyllithium, isobutyllithium, and tert-butyllithium. More preferably, the organolithium is n-butyllithium.

[0057] In step 1, the contact temperature between the precursor compound and the heterocyclic compound can be 0-65°C, and the contact duration can be 1-120 hours, preferably 1.2-80 hours, more preferably 1.5-40 hours, and even more preferably 2-10 hours. In step 1, the precursor compound and the heterocyclic compound lithium salt are contacted in a first solvent, preferably one or more of tetrahydrofuran, diethyl ether, dioxane, and hexane. The precursor compound and the heterocyclic compound can be separately mixed with a portion of the first solvent to form a solution. The solution containing the precursor compound is then mixed with the solution containing the heterocyclic compound, thereby allowing the precursor compound and the heterocyclic compound lithium salt to react.

[0058] In step 1, it is preferable to first contact the organic lithium with the heterocyclic compound to form a lithium salt, and then contact it with the precursor compound. The structure of the lithium salt is shown in Formulas 2-4.

[0059]

[0060] The heterocyclic compound can be dissolved in a first solvent and placed in an environment of -78°C to 0°C, and then alkyllithium is added to carry out the reaction. The reaction temperature of the heterocyclic compound with the alkyllithium is preferably -78°C to 60°C, more preferably -50°C to 50°C, and even more preferably -10°C to 30°C; the reaction time is preferably 0.8-10 h, more preferably 0.8-8 h, and even more preferably 1-5 h.

[0061] In the preparation method, the mixture formed by contacting the precursor compound and the heterocyclic compound in step 1 is not separated and is directly contacted with the amine in step 2, which is the transition metal complex. In step 2, the mixture obtained in step 1 is preferably contacted with the amine in a second solvent, preferably one or more of toluene, xylene, and chlorobenzene. Preferably, at least a portion of the first solvent is removed from the mixture obtained in step 1 to obtain a mixture with at least a portion of the first solvent removed, and this mixture is then mixed with the second solvent, thereby allowing the contact in step 2 to take place in the second solvent.

[0062] In the preparation method, in step 2, the mixture obtained in step 1 can be contacted with the amine at a temperature of 0-30°C for a duration of 1-48 hours.

[0063] In the preparation method, the transition metal complex according to the present invention can be separated from the mixture obtained in step 2 using conventional methods. In a preferred embodiment, at least a portion of the second solvent in the reaction mixture obtained in step 2 can be removed, a third solvent can be added to the reaction mixture to which at least a portion of the second solvent has been removed, followed by solid-liquid separation, collection of the liquid phase, removal of the solvent from the liquid phase, and the remaining solid phase being the transition metal complex. The third solvent can be one or more of hexane, heptane, and toluene.

[0064] According to the polymerization method of the present invention, the transition metal complex is contacted with a conjugated diene in the presence of a co-catalyst, causing the conjugated diene to undergo a polymerization reaction. The co-catalyst can be a commonly used co-catalyst in the field of olefin polymerization.

[0065] In a preferred embodiment, the cocatalyst is an organoaluminum compound and / or an organoboron compound.

[0066] The organoaluminum compound is preferably an aluminum oxane and / or a compound of formula V.

[0067]

[0068] In formula V, R 17 R 18 and R 19 Whether the two are the same or different, they are each independently selected from hydrogen, C1-C 10 Alkyl, C1-C 10 alkoxy groups, C6-C 20 aryl, C7-C 15 alkylaryl, C7-C 15 Aryl groups and hydrogen atoms, and R 17 R 18 and R 19 They are not both hydrogen atoms.

[0069] The C1-C 10 Alkyl groups include C1-C 10 Straight-chain alkyl, C3-C 10 Branched alkyl groups and C3-C 10 Specific examples of cycloalkyl groups may include, but are not limited to: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, pentyl and its various isomers, hexyl and its various isomers, heptyl and its various isomers, octyl and its various isomers, nonyl and its various isomers, decyl and its various isomers, cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.

[0070] The C1-C 10Specific examples of alkoxy groups may include, but are not limited to: methoxy, ethoxy, propoxy, and butoxy.

[0071] The C6-C 20 Specific examples of aryl groups may include, but are not limited to: phenyl, tolyl, ethylphenyl, propanylphenyl (wherein, the propyl group may be n-propyl or isopropyl), butylphenyl (wherein, the butyl group may be n-butyl, sec-butyl, isobutyl or tert-butyl), naphthyl, anthraceneyl or phenanthryl.

[0072] The alkylaryl group refers to an aryl group having an alkyl substituent. Specific examples of the alkylaryl group may include, but are not limited to, tolyl, ethylphenyl, dimethylphenyl, and diethylphenyl.

[0073] The aralkyl group refers to an alkyl group having an aryl substituent. Specific examples of the aralkyl group may include, but are not limited to, benzyl, phenethyl, 1-phenylpropyl, 2-phenylpropyl, and 3-phenylpropyl.

[0074] Specific examples of the organoaluminum compounds may include, but are not limited to: diethylaluminum hydride, di-n-propylaluminum hydride, di-n-butylaluminum hydride, diisobutylaluminum hydride, diphenylaluminum hydride, di(p-tolyl)aluminum hydride, dibenzylaluminum hydride, phenylethylaluminum hydride, phenyl-n-propylaluminum hydride, p-tolylethylaluminum hydride, p-tolyl-n-propylaluminum hydride, p-tolylisopropylaluminum hydride, benzylethylaluminum hydride, benzyl-n-propylaluminum hydride, benzylisopropylaluminum hydride, ethylaluminum dihydride, butyl dihydride. Aluminum chloride, isobutylaluminum dihydrogen hydride, octylaluminum dihydrogen hydride, pentylaluminum dihydrogen hydride, diethylaluminum ethoxide, dipropylaluminum ethoxide, trimethylaluminum, triethylaluminum, tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tripentylaluminum, trihexylaluminum, tricyclohexylaluminum, trioctylaluminum, triphenylaluminum, tri(p-tolyl)aluminum, tribenzylaluminum, ethyl diphenylaluminum, ethyl di(p-tolyl)aluminum, ethyl di(benzyl)aluminum, diethylphenylaluminum, diethyl p-tolyl)aluminum, and diethylbenzylaluminum.

[0075] In a preferred example, in equation V, R 17 R 18 and R 19 It is hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, or isobutyl, and R 17 R 18 and R 19 At most one of them is hydrogen. More preferably, in formula V, R 17 R 18 and R 19 It is hydrogen or butyl, and R 17 R 18 and R 19 At most one of them is hydrogen.

[0076] In a preferred embodiment, the organoaluminum compound is preferably triisobutylaluminum and / or diisobutylaluminum hydride.

[0077] The organoboron compound is preferably an organoborate. The organoborate is an ionic compound composed of a borate anion and a cation.

[0078] Specific examples of the borate anion may include, but are not limited to: tetraphenylborate, tetra(monofluorophenyl)borate, tetra(difluorophenyl)borate, tetra(trifluorophenyl)borate, tetra(tetrafluorophenyl)borate, tetra(pentafluorophenyl)borate, tetra(tetrafluoromethylphenyl)borate, tetra(tolyl)borate, tetra(xylyl)borate, (triphenyl-pentafluorophenyl)borate, [tri(pentafluorophenyl)phenyl]borate, and undecanoyl-7,8-dicarboundecanoate.

[0079] Specific examples of the cations may include, but are not limited to: carbium cations, oxonium cations, ammonium cations, phosphine cations, cycloheptatrienyl cations, and ferrocene cations containing transition metals. Among them, carbium cations include trisubstituted carbium cations, such as triphenylcarbium cations and tri(substituted phenyl)carbium cations. More specific examples of tri(substituted phenyl)carbium cations include tri(tolyl)carbium cations. Specific examples of ammonium cations may include, but are not limited to: trialkylammonium cations, such as trimethylammonium cations, triethylammonium cations, tripropylammonium cations, and tributylammonium cations; N,N-dialkylphenylammonium cations, such as N,N-dimethylphenylammonium cations, N,N-diethylphenylammonium cations, and N,N-2,4,6-pentamethylphenylammonium cations; and dialkylammonium cations, such as diisopropylammonium cations and dicyclohexylammonium cations. Specific examples of phosphine cations may include, but are not limited to, triaryl cations, such as triphenylphosphine cation, tri(tolyl)phosphine cation, and tri(xyl)phosphine cation.

[0080] In a preferred embodiment, the organoboron compound is preferably N,N-dimethylphenylammonium tetra(pentafluorophenyl)borate and / or triphenylmethyl-tetra(pentafluorophenyl)borate.

[0081] In the catalyst composition, the organoaluminum compound and organoboron compound, which serve as co-catalysts, can be used alone or in combination.

[0082] In a preferred embodiment, the cocatalyst is an organoaluminum compound and an organoboron compound. More preferably, the cocatalyst is triisobutylaluminum and N,N-dimethylphenylammonium tetra(pentafluorophenyl)borate. In this preferred embodiment, the molar ratio of the organoaluminum compound to the organoboron compound in the cocatalyst can be 1:0.01-100, preferably 1:0.1-90, more preferably 1:0.5-60, where the organoaluminum compound is calculated as aluminum and the organoboron compound as boron. In this preferred embodiment, the amount of the cocatalyst can be conventionally selected. When the cocatalyst contains an organoboron compound, the molar ratio of the transition metal complex to the organoboron compound is preferably 1:0.1-10, more preferably 1:0.5-5.

[0083] The polymerization method according to the present invention can employ conventional polymerization methods. In one embodiment, the polymerization method according to the present invention employs solution polymerization. In this embodiment, the solvent used in the solution polymerization can be one or more selected from toluene, hexane, and chlorobenzene.

[0084] According to the polymerization method of the present invention, the temperature for polymerizing ethylene with conjugated diene can be from -100°C to 150°C, preferably from 10 to 50°C.

[0085] According to the polymerization method of the present invention, by employing the transition metal complex, not only can the polymerization efficiency of conjugated dienes be effectively improved and the yield of conjugated diene polymers be increased, but the structural regularity of conjugated dienes can also be controlled, so that the conjugated diene structural units have a high degree of structural regularity.

[0086] According to a second aspect of the present invention, the present invention provides a conjugated diene polymer prepared by the method described in the first aspect of the present invention.

[0087] In a preferred embodiment, the conjugated diene is butadiene, and the conjugated diene polymer is polybutadiene. In the polybutadiene, based on the total amount of butadiene structural units, the content of cis-1,4-structural units is 85 mol% or more, preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 98 mol% or more. The number-average molecular weight (Mn) of the polybutadiene is... n The molecular weight distribution index (Mi) can range from 50,000 to 2,000,000, preferably from 80,000 to 1,500,000. w / M n The value can be 1.2-5, preferably 1.5-4.

[0088] In this invention, the content of cis-1,4-structural units in polybutadiene was determined by carbon nuclear magnetic resonance spectroscopy (CMR).13 The molecular weight distribution index of polybutadiene was determined by gel permeation chromatography, using monodistributed polystyrene as the standard sample.

[0089] The present invention will be described in detail below with reference to embodiments, but this does not limit the scope of the invention.

[0090] In the following examples and comparative examples, the molecular weight and molecular weight distribution index (M) of the polymers are... w / M n The assay was performed using an Agilent Technologies 1260 Infinity II high-temperature gel permeation chromatograph, employing two MIXD-B columns (300 × 7.5 mm) and one Guard column (50 × 7.5 mm). The mobile phase was trichlorobenzene, with a flow rate of 1 mL / min; the sample concentration was 1 mg / mL, and the injection volume was 200 μL; the test temperature was 150 °C; and monodistributed polystyrene was used as the standard sample.

[0091] In the following examples and comparative examples, nuclear magnetic resonance (NMR) spectroscopy was performed using a commercially available 400MHz NMR spectrometer from Bruker. Polybutadiene was tested at room temperature with deuterated chloroform as the solvent and tetramethylsilane (TMS) as the internal standard. Ethylene-butadiene copolymer was tested at 100°C with deuterated tetrachloroethane as the solvent. The content of cis-1,4 structural units in the butadiene structural units was determined based on the polymer... 13 Calculations from the C10 NMR spectra showed that the peaks at 26.5–27.5 ppm corresponded to carbon atoms in the cis-1,4 structural units, while the peaks at 26.5–27.5 ppm and 31.5–32.5 ppm corresponded to carbon atoms in the butadiene structural units. Here, a cis structural unit refers to a structural unit with a cis configuration, and a cis-1,4 structural unit refers to a structural unit formed by 1,4-polymerization of butadiene with a cis configuration.

[0092] In the following examples and comparative examples, the formula for calculating the monomer conversion rate is as follows:

[0093] Monomer conversion rate (%) = mass of polymer obtained / mass of added monomer × 100%.

[0094] Preparation Examples 1-4 were used to prepare transition metal complexes according to the present invention.

[0095] Preparation Example 1

[0096] Synthesis of bis(2-methyl-3,5-diphenyl-6-hydrocyclopentadienthiophene)gadolinium bis(trimethylsilylamide) (the complex shown in Formula II)

[0097]

[0098] Under a nitrogen atmosphere, 20 mL of a THF solution containing a lithium salt (1.819 g, 6.2 mmol) synthesized from 2-methyl-3,5-diphenyl-6-hydrocyclopentadienthiophene and n-butyllithium was slowly added dropwise to 40 mL of a THF solution of GdCl3 (0.791 g, 3 mmol). The mixture was then stirred at 65 °C for 6 hours. Subsequently, the THF was distilled off under reduced pressure, and 50 mL of toluene was added. Then, 20 mL of a toluene solution of KN(SiMe3)2 (0.519 g, 2.6 mmol) was slowly added dropwise to the mixture, followed by stirring at room temperature (25 °C) for 12 hours. The toluene was then distilled off under reduced pressure, 100 mL of hexane was added, and the precipitate was removed by filtration. Subsequently, the hexane was distilled off under reduced pressure to give the target product (1.336 g, 50% yield) as a pale yellow solid. The product was analyzed using elemental analysis, and the results were: C 61.91; H 5.42.

[0099] Preparation Example 2

[0100] Synthesis of bis(2,5-dimethyl-3-phenyl-6-hydrocyclopentadienthiophene)scandium bis(dimethylsilylamide) (the complex shown in Formula III)

[0101]

[0102] The transition metal complex was prepared using the same method as in Preparation Example 1, except that ScCl3 was used instead of GdCl3, 2,5-dimethyl-3-phenyl-6-hydrocyclopentadienthiophene was used instead of 2-methyl-3,5-diphenyl-6-hydrocyclopentadienthiophene, and KN(SiMe2H)2 was used instead of KN(SiMe3)2. The target product (1.183 g, yield 63%) was obtained as a pale yellow solid. Elemental analysis of the product yielded the following results: C 65.91; H 6.76.

[0103] Preparation Example 3

[0104] Synthesis of bis(2-methyl-3-phenyl-5-isopropyl-6-hydro-cyclopentadienthiophene)gadolinium bis(trimethylsilylamide) (the complex shown in Formula IV)

[0105]

[0106] The transition metal complex was prepared using the same method as in Preparation Example 1, except that 2-methyl-3,5-diphenyl-6-hydrocyclopentadienthiophene was used instead of 2-methyl-3,5-diphenyl-6-hydrocyclopentadienthiophene in Preparation Example 1, yielding a white solid target product (1.357 g, yield 55%). Elemental analysis of the product yielded the following results: C 58.28; H 6.36.

[0107] Preparation Example 4

[0108] Synthesis of bis(2,5-dimethyl-3-phenyl-4-trimethylsilyl-6-hydro-cyclopentadienthiophene)gadolinium bis(trimethylsilylamide) (the complex shown in Formula V)

[0109]

[0110] The transition metal complex was prepared using the same method as in Preparation Example 1, except that 2-methyl-3,5-diphenyl-6-hydrocyclopentadienthiophene was used instead of 2,5-dimethyl-4-trimethylsilyl-6-hydrocyclopentadienthiophene in Preparation Example 1, yielding a white solid target product (1.232 g, yield 45%). Elemental analysis of the product yielded the following results: C 55.27; H 6.63.

[0111] Preparation of Comparative Example 1

[0112] Complex VI was synthesized according to the method described in Dalton Trans., 2008, 2531-2533.

[0113]

[0114] Preparation of Comparative Example 2

[0115] Complex VII was synthesized according to the method described in Angew. Chem. Int. Ed., 2017(56), 6975-6979.

[0116]

[0117] Examples 1-4 are used to illustrate the present invention.

[0118] Example 1

[0119] In a glove box under argon atmosphere, 4.46 mg of the complex shown in Formula II and 4.00 mg of N,N-dimethylphenylamine tetra(pentafluorophenyl)borate were dissolved in 3.6 mL of toluene in a glass bottle, and 0.1 mL of 1 M triisobutylaluminum hexane solution was added. After complete dissolution, 3.5 mL of butadiene solution (containing 0.54 g of butadiene) was added. Polymerization was carried out at room temperature (25 °C) for 1 hour. After polymerization, a small amount of methanol containing hydrochloric acid was added to terminate the reaction. The product was poured into a large amount of ethanol to separate the polymer, which was then washed with ethanol. The polymer was dried in a vacuum oven until it no longer decreased in weight, thus obtaining polybutadiene. The monomer conversion rate was calculated to be 100%, and the number average molecular weight (Mn) of the polymer was determined by GPC analysis. n The molecular weight distribution index (M) is 112000. w / M n The value is 1.2.

[0120] Nuclear magnetic resonance spectroscopy analysis confirmed that the molar content of cis-1,4-structural units in the obtained polybutadiene was greater than 99%.

[0121] Example 2

[0122] In a glove box under argon atmosphere, 4.12 mg of the complex shown in Formula IV and 4.00 mg of N,N-dimethylphenylamine tetra(pentafluorophenyl)borate were dissolved in 3.6 mL of toluene in a glass bottle, followed by the addition of 0.1 mL of 1 M triisobutylaluminum hexane solution. After complete dissolution, 3.5 mL of butadiene solution (containing 0.54 g of butadiene) was added. Polymerization was carried out at room temperature (25 °C) for 2 hours. After polymerization, a small amount of methanol containing hydrochloric acid (2‰ by weight, hydrochloric acid is calculated as HCl) was added to terminate the reaction. The product was poured into a large amount of ethanol to separate the polymer, which was then washed with ethanol. The polymer was dried in a vacuum oven until it no longer decreased in weight, thus obtaining polybutadiene. The monomer conversion rate was calculated to be 100%, and the number average molecular weight (Mn) of the polymer was determined by GPC analysis. n The molecular weight distribution index (M) is 101000. w / M n The value is 1.4.

[0123] Nuclear magnetic resonance spectroscopy analysis confirmed that the molar content of cis-1,4-structural units in the obtained polybutadiene was greater than 99%.

[0124] Example 3

[0125] In a glove box under argon atmosphere, 4.12 mg of the complex shown in Formula III and 4.61 mg of triphenylmethyl-tetra(pentafluorophenyl)borate were dissolved in 3.6 mL of toluene in a glass bottle, and 0.1 mL of 1 M triisobutylaluminum hexane solution was added. After complete dissolution, 3.5 mL of butadiene solution (containing 0.54 g of butadiene) was added. Polymerization was carried out at room temperature (25 °C) for 2 hours. After polymerization, a small amount of methanol containing hydrochloric acid (2 wt%, hydrochloric acid is calculated as HCl) was added to terminate the reaction. The product was poured into a large amount of ethanol, the polymer was separated, and washed with ethanol. The product was dried in a vacuum oven until the weight no longer decreased, thus obtaining polybutadiene. The monomer conversion rate was calculated to be 100%, and the number average molecular weight (Mn) of the polymer was determined by GPC analysis. n The molecular weight distribution index (M) is 145,000. w / M n The value is 1.4.

[0126] Nuclear magnetic resonance spectroscopy analysis confirmed that the molar content of cis-1,4-structural units in the obtained polybutadiene was 91.5%.

[0127] Example 4

[0128] In a glove box under argon atmosphere, 4.56 mg of the complex shown in Formula V and 4.00 mg of N,N-dimethylphenylamine tetra(pentafluorophenyl)borate were dissolved in 3.6 mL of toluene in a glass bottle, and 0.1 mL of 1 M triisobutylaluminum hexane solution was added. After complete dissolution, 3.5 mL of butadiene solution (containing 0.54 g of butadiene) was added. Polymerization was carried out at room temperature (25 °C) for 2 hours. After polymerization, a small amount of methanol containing hydrochloric acid (2 wt%, hydrochloric acid is calculated as HCl) was added to terminate the reaction. The product was poured into a large amount of ethanol, the polymer was separated, and washed with ethanol. The product was dried in a vacuum oven until the weight no longer decreased, thus obtaining polybutadiene. The monomer conversion rate was calculated to be 100%, and the number average molecular weight (Mn) of the polymer was determined by GPC analysis. n The molecular weight distribution index (M) is 125,000. w / M n The value is 1.3.

[0129] Nuclear magnetic resonance spectroscopy analysis confirmed that the molar content of cis-1,4-structural units in the obtained polybutadiene was greater than 99%.

[0130] Comparative Example 1

[0131] In a glove box under argon atmosphere, 3.50 mg of the complex shown in Formula VI and 4.00 mg of N,N-dimethylphenylamine tetra(pentafluorophenyl)borate were dissolved in 3.6 mL of toluene in a glass bottle, and 0.1 mL of 1 M triisobutylaluminum hexane solution was added. After complete dissolution, 3.5 mL of butadiene solution (containing 0.54 g of butadiene) was added. Polymerization was carried out at room temperature (25 °C) for 2 hours. After polymerization, a small amount of methanol containing hydrochloric acid (2 wt%, hydrochloric acid is calculated as HCl) was added to terminate the reaction. The product was poured into a large amount of ethanol, the polymer was separated, and washed with ethanol. The product was dried in a vacuum oven until the weight no longer decreased, thus obtaining polybutadiene. The monomer conversion rate was calculated to be 96.3%, and the number average molecular weight (Mn) of the polymer was determined by GPC analysis. n The molecular weight distribution index (M) is 125,000. w / M n The value is 1.2.

[0132] Nuclear magnetic resonance spectroscopy analysis confirmed that the molar content of cis-1,4-structural units in the obtained polybutadiene was greater than 99%.

[0133] Comparative Example 2

[0134] In a glove box under argon atmosphere, 2.93 mg of the complex shown in Formula VII and 4.61 mg of triphenylmethyl-tetra(pentafluorophenyl)borate were dissolved in 3.6 mL of toluene in a glass bottle, and 0.1 mL of 1 M triisobutylaluminum hexane solution was added. After complete dissolution, 3.5 mL of butadiene solution (containing 0.54 g of butadiene) was added. Polymerization was carried out at room temperature (25 °C) for 2 hours. After polymerization, a small amount of methanol containing hydrochloric acid (2 wt%, hydrochloric acid is calculated as HCl) was added to terminate the reaction. The product was poured into a large amount of ethanol, the polymer was separated, and washed with ethanol. The product was dried in a vacuum oven until the weight no longer decreased, thus obtaining polybutadiene. The monomer conversion rate was calculated to be 100%, and the number average molecular weight (Mn) of the polymer was determined by GPC analysis. n The molecular weight distribution index (M) is 123,000. w / M n The value is 1.4.

[0135] Nuclear magnetic resonance spectroscopy analysis confirmed that the molar content of cis-1,4-structural units in the obtained polybutadiene was 85.3%.

[0136] The results of Examples 1-4 show that the polymerization method according to the present invention uses the transition metal complex shown in Formula I as a catalyst. This transition metal complex exhibits enhanced catalytic activity, effectively increasing polymer yield and polymerization efficiency, and has industrial application value. Furthermore, this transition metal complex also possesses good ability to regulate conjugated diene structural units, achieving a higher content of cis-1,4-structural units.

[0137] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for polymerizing a conjugated diene, the method comprising contacting at least one conjugated diene with a transition metal complex of Formula I under polymerization reaction conditions. (Formula I) In Equation I, Ln is scandium or gadolinium; R2and R7are each independently C6-C10aryl; and 30 C6-C10aryl; and R4and R9are each independently C1-C 20 alkyl or C6-C 30 aryl; R1, R3, R5, R6, R8 and R 10 Whether the two are the same or different, they are each independently hydrogen, C1-C 20 alkyl or -SiR 23 R 24 R 25 R 23 R 24 and R 25 Whether they are the same or different, they are each independently hydrogen or C1-C 20 alkyl groups, and R 23 R 24 and R 25 At least one of them is C1-C 20 Alkyl groups; R 11 R 12 R 13 R 14 R 15 and R 16 Whether the same or different, each is independently hydrogen or a C1-C5 alkyl group, and R 11 R 12 and R 13 At least one of them is a C1-C5 alkyl group, R 14 R 15 and R 16 At least one of them is a C1-C5 alkyl group; E can be either O or S.

2. The method of claim 1, wherein, In Formula I, R1 and R6 are each independently C1-C5 alkyl groups, and R2, R4, R7, and R9 are each independently C6-C5 alkyl groups. 12 Aryl groups, R3, R5, R8 and R 10 Both are hydrogen.

3. The method of claim 1, wherein, In Formula I, R1 and R6 are methyl groups, and R2, R4, R7 and R9 are phenyl groups.

4. The method of claim 1, wherein, In Equation I, R1, R4, R6, and R9 are each independently C1-C 20 The alkyl group, R2 and R7 are each independently C6-C. 30 Aryl groups, R3, R5, R8 and R 10 Both are hydrogen.

5. The method of claim 1, wherein, R1, R4, R6, and R9 are each independently C1-C5 alkyl, R2and R7are each independently C6-C 12 aryl.

6. The method of claim 1, wherein, R1, R4, R6, and R9 are each independently methyl or isopropyl, while R2 and R7 are phenyl.

7. The method of claim 1, wherein, In Formula I, R1 and R6 are methyl, R4 and R9 are methyl or isopropyl, and R2 and R7 are phenyl.

8. The method of claim 1, wherein, In Equation I, R1, R4, R6, and R9 are each independently C1-C 20 The alkyl group, R2 and R7 are each independently C6-C. 30 Aryl, R5 and R 10 Both are hydrogen, and R3 and R8 are independently -SiR. 23 R 24 R 25 R 23 R 24 and R 25 Whether they are the same or different, each is independently C1-C 20 Alkyl groups.

9. The method of claim 1, wherein, R1, R4, R6, and R9 are each independently C1-C5 alkyl groups, and R2 and R7 are each independently C6-C5 alkyl groups. 12 The aryl group, R3 and R8, are each independently -SiR 23 R 24 R 25 R 23 R 24 and R 25 Whether the groups are the same or different, each is independently hydrogen or a C1-C5 alkyl group, and R 23 R 24 and R 25 At least one of them is a C1-C5 alkyl group.

10. The method of claim 1, wherein, R1, R4, R6and R9are methyl, R2and R7are phenyl, and R3and R8are each independently -SiR 23 R 24 R 25 , R 23 , R 24 and R 25 are each methyl.

11. The method of claim 1, wherein, The transition metal complex is a complex shown in Formula II, Formula III, Formula IV, or Formula V. (Formula II) (Formula III) (Formula IV) (Formula V).

12. The method of any of claims 1-11, wherein, The contact takes place in the presence of a co-catalyst.

13. The method of claim 12, wherein, The cocatalyst is an organoaluminum compound and / or an organoboron compound.

14. The method of claim 13, wherein, The organoaluminum compound is an aluminum oxane and / or a compound represented by formula V. (Formula V) In formula V, R 17 R 18 and R 19 Whether the two are the same or different, they are each independently selected from hydrogen, C1-C 10 Alkyl, C1-C 10 alkoxy groups, C6-C 20 aryl, C7-C 15 alkylaryl, C7-C 15 Aryl groups and hydrogen atoms, and R 17 R 18 and R 19 They are not both hydrogen atoms.

15. The method of claim 13, wherein, The organoaluminum compound is triisobutylaluminum and / or diisobutylaluminum hydride.

16. The method of claim 13, wherein, The organoboron compound is an organoborate.

17. The method of claim 13, wherein, The organoboron compound is N,N-dimethylphenylammonium tetra(pentafluorophenyl)borate and / or triphenylmethyl-tetra(pentafluorophenyl)borate.

18. The method of claim 12, wherein, The cocatalyst is an organoaluminum compound and an organoboron compound.

19. The method of claim 18, wherein, The organoaluminum compound is triisobutylaluminum and / or diisobutylaluminum hydride.

20. The method of claim 18, wherein, The organoboron compound is N,N-dimethylphenylammonium tetra(pentafluorophenyl)borate and / or triphenylmethyl-tetra(pentafluorophenyl)borate.

21. The method of claim 18, wherein, In the co-catalyst, the molar ratio of the organoaluminum compound to the organoboron compound is 1:0.01-100, wherein the organoaluminum compound is calculated as aluminum and the organoboron compound is calculated as boron.

22. The method of claim 18, wherein, In the co-catalyst, the molar ratio of the organoaluminum compound to the organoboron compound is 1:0.1-90, wherein the organoaluminum compound is calculated as aluminum and the organoboron compound is calculated as boron.

23. The method of claim 18, wherein, In the co-catalyst, the molar ratio of the organoaluminum compound to the organoboron compound is 1:0.5-60, wherein the organoaluminum compound is calculated as aluminum and the organoboron compound is calculated as boron.

24. The method of claim 18, wherein, The molar ratio of the transition metal complex to the organoboron compound is 1:0.1-10.

25. The method of claim 18, wherein, The molar ratio of the transition metal complex to the organoboron cofactor is 1:0.5-5.

26. The method of any one of claims 1-11, wherein, The conjugated diene is selected from one or more compounds shown in Formula VI. (Formula VI) In formula VI, R 20 , R 21 and R 22 are the same or different, each selected from the group consisting of hydrogen and C1-C5 straight chain or branched chain alkyl.

27. The method of any one of claims 1-11, wherein, The conjugated diene is butadiene.

28. A conjugated diene polymer prepared by the method of any one of claims 1-27.

29. The conjugated diene polymer of claim 28, wherein, The conjugated diene polymer is polybutadiene.

30. The conjugated diene polymer of claim 29, wherein, In the butadiene, based on the total amount of butadiene structural units, the content of cis-1,4-structural units is 85 mol% or more.

31. The conjugated diene polymer of claim 29, wherein, In the butadiene, based on the total amount of butadiene structural units, the content of cis-1,4-structural units is 95 mol% or more.

32. The conjugated diene polymer of claim 29, wherein, In the butadiene, based on the total amount of butadiene structural units, the content of cis-1,4-structural units is 98 mol% or more.

33. The conjugated diene polymer according to any one of claims 29-32, wherein, The butadiene has a number-average molecular weight of 50,000 to 2,000,000 and a molecular weight distribution index of 1.2-5.

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