Catalyst composition for ring-opening polymerization

Abstract

To provide a new synthetic method capable of precisely controlling the molecular weight and molecular weight distribution of a produced polymer by suppressing a depolymerization reaction which is a reverse reaction in a polymerization reaction of polysiloxane or the like.SOLUTION: It has been found that by using a novel co-catalyst system comprising an organic base compound and an imidazole analogue, a depolymerization reaction can be highly suppressed in a ring-opening polymerization using cyclic siloxanes as monomers, and a polysiloxane having a desired molecular weight and molecular weight distribution can be obtained.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a novel catalyst composition for ring-opening polymerization and a ring-opening polymerization method using the catalyst composition. [Background technology]

[0002] Polysiloxanes are known as extremely versatile materials with a wide range of uses, from biomaterials such as artificial skin, insulating materials for electronic substrates, adhesives, and even cosmetics. Therefore, there has been a demand for a simple method for synthesizing polysiloxanes with well-defined structures. To solve this problem, the synthesis of polysiloxanes using organic catalysts has been reported (e.g., Non-Patent Document 1). Among these, triazabicyclodecene (TBD), a guanidine base, has been reported to exhibit high catalytic activity and produce polysiloxanes with a narrow distribution. The effectiveness of guanidine bases has been reconfirmed 15 years later (Non-Patent Document 2).

[0003] On the other hand, because the initiation point of polymerization is a highly polar or ionic group, there is a mismatch with the polarity of the solvent that can dissolve the resulting polysiloxanes, and it has generally been difficult to synthesize polysiloxanes with controlled molecular weights and molecular weight distributions from polyfunctional initiators, particularly those with many polar or ionic groups. To address this issue, the present inventors discovered that urea analogs solubilize silanols, and attempted to synthesize polysiloxanes with controlled molecular weights and molecular weight distributions by ring-opening polymerization of cyclic siloxanes using urea analog anions as catalysts and polyfunctional silanols as initiators (Non-Patent Document 3).

[0004] However, in general polysiloxane synthesis, the reverse reaction of polymerization, depolymerization, occurs as the polymerization proceeds, becoming prominent, eventually reaching equilibrium and producing a polymer with a broad molecular weight distribution. Therefore, there remains the problem that it is difficult to obtain an ideal polymer with a narrow molecular weight distribution, etc. This type of polymerization is called equilibrium polymerization, and in a system in which the polymerization and depolymerization reactions proceed reversibly, there is a problem that the product inevitably changes from a kinetically controlled product to a thermodynamically controlled product (e.g., Non-Patent Documents 4 and 5). [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Org.Lett.2006,8,21,4683-4686,DOI:10.1021 / ol0614166 [Non-patent document 2] Chem.Sci.2018,9,2879-2891,10.1039.1039 / c7sc04234e [Non-patent document 3] Adv.Sci.2021,8,2101143,DOI:10.1002 / advs.202101143 [Non-patent document 4] Molecules 2021,26,2755,DOI:10.3390 / molecules26092755 [Non-Patent Document 5] Science 2023,381,1011-1014,DOI:10.1126 / science.adi1342 Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, an object of the present invention is to provide a novel synthesis method that can suppress the reverse depolymerization reaction in the polymerization reaction of polysiloxanes and the like, and enable precise control of the molecular weight and molecular weight distribution of the resulting polymer. [Means for solving the problem]

[0007] The present inventors conducted extensive research to solve the above-mentioned problems and attempted to find a catalyst system that could create an extremely large rate difference between the polymerization and depolymerization reactions, so that the progress of the depolymerization reaction could be ignored on the normal time scale of ring-opening polymerization. As a result, they discovered that by using a novel cocatalyst system consisting of an organic base compound and an imidazole analog, the depolymerization reaction can be highly suppressed in ring-opening polymerization using cyclic siloxanes as monomers, thereby producing polysiloxanes with desired molecular weights and molecular weight distributions. Furthermore, by utilizing the fact that the suppression of the depolymerization reaction maintains the growing end of the polymerization as an active species, they discovered for the first time that living ring-opening polymerization of cyclic siloxanes can be achieved in the strict sense. They also found that the above cocatalyst system is widely applicable to ring-opening polymerization reactions of compounds other than polysiloxanes. Based on these findings, the present invention was completed.

[0008] That is, in one aspect, the present invention relates to a catalyst system capable of suppressing undesired depolymerization reactions in ring-opening polymerization, more specifically, <1> A catalyst composition for ring-opening polymerization, comprising an organic base compound and a compound having an imidazole skeleton; <2> catalyzing the polymerization reaction of cyclic monomers but suppressing the depolymerization reaction in the polymer that is the product of ring-opening polymerization, <1> a catalyst composition according to <3> the compound having an imidazole skeleton has a substituent selected from an optionally substituted branched alkyl group, an optionally substituted aryl group, an alkoxy group, a siloxane group, a fluoroalkyl group, and a combination thereof; <1> a catalyst composition according to <4> The compound having an imidazole skeleton has 1 to 3 phenyl groups. <1> a catalyst composition according to <5> The organic base compound has a pK of 18 or more. b The compound having the value <1> a catalyst composition according to <6> The organic base compound has an imino group, a guanidine moiety, an amidine moiety, or an amino group. <1> a catalyst composition according to <7> The molar ratio of the organic base compound to the compound having an imidazole skeleton is in the range of 100:1 to 1:100. <1> a catalyst composition according to <8> The organic base compound and the compound having an imidazole skeleton are present in the form of a salt. <1> a catalyst composition according to <9> The compound having an imidazole skeleton includes a structure that functions as a polymerization initiator. <1> a catalyst composition according to claim 1; and This provides:

[0009] In another aspect, the present invention relates to a ring-opening polymerization process using the above catalyst composition, and the products therefrom, more specifically <10> A ring-opening polymerization method in which polymerization proceeds by ring-opening of a cyclic monomer, the method comprising carrying out a polymerization reaction in the presence of the catalyst composition according to any one of claims 1 to 9; <11> The method of claim 1, wherein the cyclic monomer is catalyzed in a polymerization reaction, but the depolymerization reaction in the polymer that is the product of the ring-opening polymerization is suppressed. <10> The method described in <12> The polymer produced by the ring-opening polymerization has a molecular weight distribution of D<1.5. <10> The method described in <13> A ring-opening polymer having a structure represented by the following formula (1) or (2): [ka] [ka] (wherein A1, A2, B1, B2, C1, and C2 each independently represent a substituent selected from a hydrogen atom, a halogen atom, an alkyl group, a halogen-substituted alkyl group, an alkenyl group, a halogen-substituted alkenyl group, an aryl group, a halogen-substituted aryl group, an alkoxy group, a siloxane group, a fluoroalkyl group, and combinations thereof, and X represents an optional polymer chain; and <14> X is a polydimethylsiloxane chain. <13> The present invention provides a ring-opening polymer according to the above. [Effects of the Invention]

[0010] According to the present invention, in the ring-opening polymerization of cyclic siloxanes or the like as monomers, depolymerization reactions can be highly suppressed, and polymers having desired molecular weights and molecular weight distributions can be obtained. The catalyst composition of the present invention has the potential for a wide range of industrial applications as a novel, inexpensive, and highly versatile polymerization catalyst. The catalyst composition of the present invention has the potential for a wide range of industrial applications as a novel, inexpensive, and highly versatile polymerization catalyst.

[0011] According to the ring-opening polymerization method using the catalyst composition of the present invention, the molecular weight distribution does not broaden even when the monomer conversion rate exceeds 90%, and the molecular weight distribution can be maintained narrow without performing a termination reaction to stop the polymerization / depolymerization reaction itself. Furthermore, the ring-opening polymerization method of the present invention enables molecular weight control in living polymerization. That is, when a monomer component is added to the system after the monomer component has been consumed, the molecular weight increases by the amount added, thereby providing the excellent effect of adjusting the molecular weight of the resulting polymer within a desired range. Furthermore, polymers obtained by the ring-opening polymerization method of the present invention, particularly polysiloxanes, are expected to be applicable to a wide variety of materials, including biomaterials (e.g., artificial skin), electronic materials (sealants and adhesives), and even cosmetic (beauty product) ingredients (shampoos and rinses). DETAILED DESCRIPTION OF THE INVENTION

[0012] The following describes embodiments of the present invention. The scope of the present invention is not limited to these descriptions, and other than the following examples, the present invention can be implemented with appropriate modifications within the scope that does not depart from the spirit of the present invention.

[0013] 1.Definition In this specification, the term "alkyl or alkyl group" may be any of a linear, branched, or cyclic aliphatic hydrocarbon groups, or a combination thereof. The number of carbon atoms in the alkyl group is not particularly limited, but for example, alkyl groups having 1 to 20 carbon atoms (C 1~20 ), 1 to 15 carbon atoms (C 1~15 ), number of carbons 1 to 10 (C 1~10 In this specification, the alkyl group may have one or more optional substituents. For example, C 1~8 Alkyl includes methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neo-pentyl, n-hexyl, isohexyl, n-heptyl, n-octyl, and the like. Examples of the substituent include, but are not limited to, an alkoxy group, a halogen atom (which may be a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), an amino group, a mono- or di-substituted amino group, a substituted silyl group, or an acyl. When an alkyl group has two or more substituents, they may be the same or different. The same applies to the alkyl moiety of other substituents containing an alkyl moiety (e.g., an alkoxy group, an arylalkyl group, and the like).

[0014] In the present specification, "alkylene" refers to a divalent group consisting of a linear or branched saturated hydrocarbon, and examples thereof include methylene, 1-methylmethylene, 1,1-dimethylmethylene, ethylene, 1-methylethylene, 1-ethylethylene, 1,1-dimethylethylene, 1,2-dimethylethylene, 1,1-diethylethylene, 1,2-diethylethylene, 1-ethyl-2-methylethylene, trimethylene, 1-methyltrimethylene, 2-methyltrimethylene, 1,1-dimethyltrimethylene, 1,2 -dimethyltrimethylene, 2,2-dimethyltrimethylene, 1-ethyltrimethylene, 2-ethyltrimethylene, 1,1-diethyltrimethylene, 1,2-diethyltrimethylene, 2,2-diethyltrimethylene, 2-ethyl-2-methyltrimethylene, tetramethylene, 1-methyltetramethylene, 2-methyltetramethylene, 1,1-dimethyltetramethylene, 1,2-dimethyltetramethylene, 2,2-dimethyltetramethylene, 2,2-di-n-propyltrimethylene, and the like.

[0015] As used herein, the term "alkenyl" refers to a straight-chain or branched-chain hydrocarbon group having at least one carbon-carbon double bond. Non-limiting examples include vinyl, allyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1,3-butadienyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1,3-pentadienyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, 5-hexenyl, and 1,4-hexanedienyl. The double bond may be in either the cis or trans conformation.

[0016] As used herein, the term "aromatic ring" refers to a monocyclic or fused polycyclic conjugated unsaturated hydrocarbon ring structure, which may contain one or more heteroatoms (e.g., oxygen atom, nitrogen atom, sulfur atom, etc.) as ring-constituting atoms.

[0017] As used herein, the term "aryl group" or "aryl" may refer to either a monocyclic or fused polycyclic aromatic hydrocarbon group, and may contain one or more heteroatoms (e.g., oxygen, nitrogen, or sulfur atoms) as ring constituent atoms. In this case, this may be referred to as a "heteroaryl" or "heteroaromatic." Whether the aryl is a monocyclic or fused ring, it may be bonded at any possible position. As used herein, the aryl group may have one or more optional substituents on its ring. Examples of such substituents include, but are not limited to, an alkoxy group, a halogen atom, an amino group, a mono- or di-substituted amino group, a substituted silyl group, or an acyl. When an aryl group has two or more substituents, these may be the same or different. The same applies to the aryl moiety of other substituents containing an aryl moiety (e.g., an aryloxy group or an arylalkyl group).

[0018] In this specification, the term "alkoxy group" refers to a structure in which the alkyl group is bonded to an oxygen atom, and examples thereof include saturated alkoxy groups that are linear, branched, cyclic, or a combination thereof. Suitable examples include methoxy, ethoxy, n-propoxy, isopropoxy, cyclopropoxy, n-butoxy, isobutoxy, s-butoxy, t-butoxy, cyclobutoxy, cyclopropylmethoxy, n-pentyloxy, cyclopentyloxy, cyclopropylethyloxy, cyclobutylmethyloxy, n-hexyloxy, cyclohexyloxy, cyclopropylpropyloxy, cyclobutylethyloxy, and cyclopentylmethyloxy groups.

[0019] As used herein, "alkylamino" and "arylamino" refer to an amino group in which the hydrogen atom of the -NH group is substituted with one or two of the above alkyl or aryl groups. Examples include methylamino, dimethylamino, ethylamino, diethylamino, ethylmethylamino, and benzylamino.

[0020] As used herein, the term "ether chain" refers to a group containing an ether bond (-O-) at any portion thereof, and can include not only -RO-R'- and -OR-, but also structures in which these groups are repeatedly linked (wherein R and R' can be branched or straight-chain hydrocarbons).

[0021] In this specification, the term "halogen atom" refers to a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom.

[0022] In this specification, when a functional group is defined as "optionally substituted," the type, substitution position, and number of substituents are not particularly limited, and when two or more substituents are present, they may be the same or different. Examples of substituents include, but are not limited to, alkyl groups, alkoxy groups, hydroxyl groups, carboxy groups, halogen atoms, sulfo groups, amino groups, alkoxycarbonyl groups, and oxo groups. These substituents may further contain substituents. Examples of such substituents include, but are not limited to, halogenated alkyl groups.

[0023] 2. Catalyst composition of the present invention The catalyst composition of the present invention provides a suitable catalytic action in a ring-opening polymerization reaction, and is a dual catalyst composition characterized by containing two compounds: 1) an organic base compound and 2) a compound having an imidazole skeleton (imidazole analogue).

[0024] Ring-opening polymerization is a type of chain polymerization, and generally refers to a reaction in which a monomer with a cyclic structure having a carbon ring or a heterocycle reacts with an active species generated from a small amount of initiator, thereby opening the ring and generating new active species of the same type, and such a reaction is repeated continuously to generate a chain polymer.

[0025] The catalyst composition of the present invention is characterized by catalyzing the polymerization reaction of cyclic monomers while suppressing depolymerization in the polymer resulting from ring-opening polymerization. Specifically, when ring-opening polymerization is performed using only the organic base compound as a catalyst, depending on the type of monomer, depolymerization, a reverse reaction of polymerization, occurs significantly as the polymerization proceeds, eventually reaching equilibrium and producing a polymer with a wide molecular weight distribution. This is because, as mentioned above, such polymerization is called equilibrium polymerization, and in a system in which polymerization and depolymerization proceed reversibly, the product inevitably changes from a kinetically controlled product to a thermodynamically controlled product. In contrast, the present invention utilizes a cocatalyst system consisting of an organic base compound and an imidazole analogue bearing a bulky group around the nitrogen atom, which serves as a hydrogen bonding site, and has found that the growing polymer end preferentially attacks small-molecular-size monomers over large-molecular-size polymer chains (depolymerization). This mechanism enables ring-opening polymerization with controlled molecular weight and molecular weight distribution. Typically, the depolymerization reaction is a transetherification reaction or a transesterification reaction.

[0026] More specifically, the catalyst composition of the present invention can control the molecular weight and molecular weight distribution by suppressing the depolymerization reaction. As a result, the molecular weight distribution does not broaden even when the monomer conversion rate exceeds 90%, and the molecular weight distribution can be maintained narrow without carrying out a termination reaction that would stop the polymerization / depolymerization reaction itself.

[0027] From another perspective, the catalyst composition of the present invention has the advantage that when a monomer component is added to the reaction system after the monomer component has been consumed, the molecular weight increases by the amount of the added monomer component, thereby making it possible to adjust the molecular weight of the resulting polymer to a desired range. In this sense, it can be said that the catalyst composition of the present invention enables ring-opening polymerization by living polymerization in the strict sense. Here, living polymerization generally refers to chain-growth polymerization that consists only of an initiation reaction and a propagation reaction during the polymerization process, and is not accompanied by side reactions that deactivate the growing chain terminus, such as irreversible termination and irreversible migration.

[0028] The organic base compound in the catalyst composition of the present invention may be any compound known in the art as a catalyst for ring-opening polymerization reactions, but preferably has a pK of 18 or more, particularly preferably 20 or more. b The organic base compounds are compounds having an imino group, a guanidine moiety, an amidine moiety, or an amino group in the molecule. More specifically, examples of such organic base compounds include 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine (BEMP), diazabicycloundecene (DBU), 1,8-bis(dimethylamino)naphthalene (DMAN), 1,8-bis(tetramethylguanidino)naphthalene (TMGN), and the phosphazene bases P1t-Bu and P4t-Bu.

[0029] [ka]

[0030] The compound having an imidazole skeleton (imidazole analog) in the catalyst composition of the present invention may be unsubstituted imidazole or 1-methylimidazole, but is preferably one having one or more bulky substituted imidazole skeletons in the molecule. Examples of such substituents include optionally substituted branched alkyl groups, optionally substituted aryl groups, alkoxy groups, siloxane groups, fluoroalkyl groups, and combinations thereof. Typically, compounds having one to three phenyl groups linked to an imidazole skeleton are preferred. More specifically, compounds having a 2,4,5-triphenylimidazole group (lophine group), a 2-phenylimidazole group, a 4-phenylimidazole group, a 4,5-diphenylimidazole group, a 2-(2-chloro)4,5-diphenylimidazole group, or a 2-(4-chloro)4,5-diphenylimidazole group are preferred. Most preferably, the compound having an imidazole skeleton has a 2,4,5-triphenylimidazole group (lophine group).

[0031] [ka]

[0032] In the catalyst composition of the present invention, the molar ratio of the organic base compound to the compound having an imidazole skeleton is preferably in the range of 100:1 to 1:100, more preferably in the range of 10:1 to 1:10, and even more preferably in the range of 3:1 to 1:3.

[0033] The organic base compound and / or the compound having an imidazole skeleton in the present invention may exist as a salt. Examples of such salts include base addition salts, acid addition salts, and amino acid salts. Examples of base addition salts include metal salts such as sodium salts, potassium salts, calcium salts, and magnesium salts, ammonium salts, and organic amine salts such as triethylamine salts, piperidine salts, and morpholine salts. Examples of acid addition salts include mineral acid salts such as hydrochlorides, sulfates, and nitrates, and organic acid salts such as carboxylates, methanesulfonates, paratoluenesulfonates, citrates, and oxalates. Examples of amino acid salts include glycine salts. However, the salts are not limited to these salts.

[0034] In some cases, the organic base compound and the compound having an imidazole skeleton can form a salt with the organic base compound and the compound having an imidazole skeleton as a cation and an anion, respectively. In particular, when the catalyst composition of the present invention is added to a polymerization reaction system containing a solvent, the organic base compound and the compound having an imidazole skeleton exhibit catalytic activity in the form of such a salt.

[0035] In a preferred embodiment, the compound having an imidazole skeleton in the catalyst composition of the present invention can contain a structure in the molecule that can function as a polymerization initiator in a ring-opening polymerization reaction. In this case, a compound in which the above-mentioned 2,4,5-triphenylimidazole group (lophine group) has been introduced into a polymerization initiator known in the art can typically be used. Such an imidazole analog can function as a cocatalyst in ring-opening polymerization and also provide a polymerization initiation point. For example, in the case of ring-opening polymerization of polysiloxane, the following compound can be mentioned, which has a structure in which SiOH, which serves as the initiation point, is linked to a lophine group:

[0036] [ka]

[0037] In some cases, the catalyst composition of the present invention may further contain a urea compound. Such a urea compound can also function as a catalyst in ring-opening polymerization. For example, the following compounds can be mentioned, in which a phenyl group, a cyclohexyl group, or a fluorinated alkyl group is introduced into urea or thiourea.

[0038] [ka]

[0039] 2. Catalyst composition of the present invention In another aspect, the present invention is directed to a ring-opening polymerization method using the above catalyst composition. More specifically, the ring-opening polymerization method of the present invention is a ring-opening polymerization method in which polymerization proceeds by ring-opening of a cyclic monomer, and includes carrying out a polymerization reaction in the presence of the above catalyst composition containing an organic base compound and a compound having an imidazole skeleton. Details of the organic base compound and the compound having an imidazole skeleton in the co-catalyst are as described above.

[0040] The cyclic monomer in the ring-opening polymerization method of the present invention is not particularly limited, but can typically be a cyclic ester, a cyclic ether, or a cyclic carbonate, and examples thereof include cyclic siloxane monomers such as hexamethylcyclotrisiloxane (D3), and lactones.

[0041] [ka]

[0042] As the polymerization initiator in the ring-opening polymerization method of the present invention, those known in the technical field can be used depending on the type of cyclic monomer used, the type of target polymer, etc. For example, when obtaining a polysiloxane by polymerization of a cyclic siloxane monomer, a compound having one or more SiOH groups can be used.

[0043] Non-limiting examples of compounds having one or more SiOH groups include the following compounds: [ka]

[0044] When the above compound I is used as a polymerization initiator, D3 as a cyclic monomer, and TBD and lophine as cocatalysts, linear polydimethylsiloxane (PDMS) can be obtained as follows. [ka]

[0045] Furthermore, when the above-mentioned compound I3 is used as a polymerization initiator, D3 as a cyclic monomer, and TBD and lophine as cocatalysts, a star-shaped (branched) PDMS can be obtained as follows. [ka]

[0046] The reaction solvent used in the ring-opening polymerization method of the present invention may be any solvent known in the art, typically an organic ether solvent. Examples of such organic solvents include hydrocarbon solvents such as toluene, ether solvents such as tetrahydrofuran (THF), ester solvents such as ethyl acetate, ketone solvents such as methyl ethyl ketone, and halogenated solvents such as chloroform.

[0047] As described above, the polymer obtained by the ring-opening polymerization method of the present invention has a narrow molecular weight distribution D because the depolymerization reaction is suppressed. The polymer preferably has a molecular weight distribution in the range of D<1.2, more preferably D<1.1. Here, the molecular weight distribution D is the value obtained by dividing the weight average molecular weight of the polymer by the number average molecular weight [weight average molecular weight (Mw)) / (number average molecular weight (Mn)), and can be measured by any method known in the technical field.

[0048] In a preferred embodiment, as described above, imidazole analogs with structures (e.g., SiOH groups) that can function as polymerization initiators can be used. PDMS with an imidazole (lophine) structure can be obtained using such compounds and TBD as catalysts and D3 as a cyclic monomer, as follows: [ka]

[0049] The polymer having the lophine group can form a dimer structure as follows: [ka]

[0050] Therefore, in a further aspect, the present invention also relates to a polymer that is a product of the above-mentioned ring-opening polymerization reaction using an imidazole analogue into which a polymerization initiation site has been introduced, and specifically, to a ring-opening polymer (and a dimer thereof) represented by the following general formula (1) or (2):

[0051] [ka] [ka]

[0052] In the above formulas (1) and (2), A1, A2, B1, B2, C1, and C2 are each independently a substituent selected from a hydrogen atom, a halogen atom, an alkyl group, a halogen-substituted alkyl group, an alkenyl group, a halogen-substituted alkenyl group, an aryl group, a halogen-substituted aryl group, an alkoxy group, a siloxane group, a fluoroalkyl group, and a combination thereof. Preferably, either A1 or A2 is a phenyl group which may have a substituent, and more preferably, both A1 and A2 are phenyl groups which may have a substituent. Preferably, B1, B2, C1, and C2 are all hydrogen atoms.

[0053] In the formula, X can be any polymer chain, but preferably X is a polydimethylsiloxane chain obtained by polymerization of cyclic siloxane monomers, although it can also be other types of polymer chains obtained from monomers such as cyclic esters, cyclic ethers, or cyclic carbonates.

[0054] The ring-opening polymer of formula (2) is a compound in which the ring-opening polymer of formula (1) is crosslinked with each other at the amino groups on the imidazole ring to form a dimer structure. [Example]

[0055] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0056] Example 1: Synthesis of linear polydimethylsiloxane by polymerization catalyzed by lophine and TBD

[0057] Linear polydimethylsiloxane (PDMS) was synthesized by the following ring-opening polymerization reaction using TBD as an organic base compound and lophine as a compound having an imidazole skeleton. [ka]

[0058] Hexamethylcyclotrisiloxane (5.35 g), tetrahydrofuran (8.2 mL), dimethylphenylsilanol (42 μL), and lophine were added to a reaction vessel and mixed. Then, a tetrahydrofuran solution (0.5 mL) of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (19 mg) was quickly added to the reaction vessel and stirred at 20° C. under nitrogen purging. During this process, approximately 0.1 mL of the solution was removed at 15, 30, 60, 90, 120, 180, 240, 300, and 1200 minutes (15, 30, 60, 90, 120, 180, 240, 360, and 600 minutes in Examples 1-3). 1 The results of H-NMR and GPC analyses are shown in Table 1.

[0059] [Table 1]

[0060] Example 2: Synthesis of linear polydimethylsiloxane by polymerization of lophine, urea, and TBD as catalyst

[0061] Next, ring-opening polymerization reactions were carried out using TBD as an organic base compound, lophine as a compound having an imidazole skeleton, and various urea derivatives.

[0062] Hexamethylcyclotrisiloxane (5.06 g), tetrahydrofuran (7.6 mL), dimethylphenylsilanol (42 μL), lophine (80 mg), and urea were added to a reaction vessel and mixed, after which a tetrahydrofuran solution (0.5 mL) of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (19 mg) was quickly added to the reaction vessel and stirred at 20°C under nitrogen purging. At this time, approximately 0.1 mL of the solution was taken out at the time points of 15 minutes, 30 minutes, 60 minutes, 90 minutes, 120 minutes, 180 minutes, 240 minutes, 360 minutes, and 600 minutes (1800 minutes, 3240 minutes, and 7500 minutes in Examples 2-2 and 2-3, and 15 minutes, 30 minutes, 60 minutes, 90 minutes, 120 minutes, 180 minutes, 240 minutes, 300 minutes, and 1300 minutes in Examples 2-4 to 2-6), 1 The results of H-NMR and GPC analyses are shown in Table 2.

[0063] [Table 2]

[0064] Example 3: Synthesis of linear polydimethylsiloxane by polymerization of imidazole derivatives with U(Ph-Cy) and TBD as catalyst

[0065] As in Example 2 above, ring-opening polymerization was carried out using various imidazole derivatives.

[0066] Hexamethylcyclotrisiloxane (2.53 g), tetrahydrofuran (3.8 mL), dimethylphenylsilanol (21 μL), an imidazole derivative, and U(Ph-Cy) (32.7 mg) were added to a reaction vessel and mixed. Then, a tetrahydrofuran solution (0.25 mL) of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (9 mg) was quickly added to the reaction vessel and stirred at 20° C. under nitrogen purging. At this time, approximately 0.1 mL of the solution was removed at 15, 30, 60, 90, 120, 180, 240, and 360 minutes. 1 The results of H-NMR and GPC analyses are shown in Table 3.

[0067] [Table 3]

[0068] Example 4: Synthesis of linear polydimethylsiloxane by polymerization of lophine, U(Ph-Cy), and organic base as catalyst

[0069] Furthermore, in the same manner as in Example 2 above, ring-opening polymerization was carried out using various organic base compounds.

[0070] Hexamethylcyclotrisiloxane (5.06 g), tetrahydrofuran (7.6 mL), dimethylphenylsilanol (42 μL), lophine (80.2 mg), and U(Ph-Cy) (63.6 mg) (U(4CF) for YGH-2-100 only) were added to a reaction vessel and mixed, after which a tetrahydrofuran solution of an organic base (0.25 mL) was quickly added to the reaction vessel and stirred at 20°C under nitrogen purging. At this time, approximately 0.1 mL of the solution was taken out at the following times: 15 minutes, 30 minutes, 60 minutes, 90 minutes, 120 minutes, 180 minutes, 240 minutes, 360 minutes, and 600 minutes (120 minutes, 1300 minutes, 2900 minutes, 7000 minutes, and 10000 minutes in Examples 4-2 to 4-3 and 4-5; 1 minute, 3 minutes, 5 minutes, 7 minutes, and 10 minutes in Example 4-7; 1600 minutes in Example 4-4; and 2700 minutes in Example 4-6). 1 The results of H-NMR and GPC analyses are shown in Table 4.

[0071] [Table 4]

[0072] Example 5: Synthesis of three-arm star polydimethylsiloxane by polymerization of lophine, U(Ph-Cy), and TBD as catalyst

[0073] Star-shaped PDMS was synthesized using 1,3,5-tris(dimethylhydroxysilyl)benzene (I3) as an initiator.

[0074] Hexamethylcyclotrisiloxane (1.67 g), tetrahydrofuran (2.5 mL), 1,3,5-tris(dimethylhydroxysilyl)benzene (27 mg), lophine (80 mg), and U(Ph-Cy) (65.4 mg) were added to a reaction vessel and mixed. Then, a tetrahydrofuran solution (0.5 mL) of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (19 mg) was quickly added to the reaction vessel and stirred at 20° C. under nitrogen purging. Approximately 0.1 mL of the solution was removed at 15, 30, 60, 90, 120, 180, 240, 360, and 600 minutes. 1 The results of H-NMR and GPC analyses are shown in Table 5.

[0075] [Table 5]

[0076] Example 6: Synthesis of lophine-terminated linear polydimethylsiloxane by polymerization using U(4CF3) and TBD as catalysts

[0077] Ring-opening polymerization was carried out using lophine with silanol moieties that could serve as initiation sites (an example in which the initiator also served as an imidazole derivative co-catalyst).

[0078] Hexamethylcyclotrisiloxane (5.16 g), tetrahydrofuran (7.6 mL), (4-(4,5-diphenyl-1H-imidazol-2-yl)phenyl)dimethylsilanol (100 mg), and U(4CF3) (408 mg) were added to a reaction vessel and mixed. Then, a tetrahydrofuran solution (0.5 mL) of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (19 mg) was quickly added to the reaction vessel and stirred at 20°C under nitrogen purging. Approximately 0.1 mL of the solution was removed at 15, 30, 60, 90, 120, 180, 240, and 360 minutes. 1 The results of H-NMR and GPC analyses are shown in Table 6.

[0079] [Table 6]

[0080] Example 7: Ring-opening polymerization of cyclic ester (δ-valerolactone) and cyclic carbonate (trimethylene carbonate) using lophine, U(Ph-Cy), and TBD as a ternary catalyst

[0081] The catalyst system of the present invention was applied to the ring-opening polymerization using a cyclic ester (δ-valerolactone) instead of a siloxane monomer.

[0082] δ-Valerolactone (0.98 mL), tetrahydrofuran (3.8 mL), 1-pyrenebutanol (37.3 mg), lophine (39.8 mg), and U(Ph-Cy) (32.7 mg) were added to a reaction vessel and mixed. Then, a tetrahydrofuran solution (0.5 mL) of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (19 mg) was quickly added to the reaction vessel and stirred at 20°C (-40°C for YGH-2-84) under nitrogen purging. At this time, approximately 0.1 mL of the solution was removed at 15, 30, 60, 90, and 120 minutes (5000 minutes for YGH-2-84). 1 Analysis was performed by H-NMR and GPC, and the results are shown in Table 7.

[0083] [Table 7]

Claims

1. A catalyst composition for ring-opening polymerization, comprising an organic base compound and a compound having an imidazole skeleton.

2. 10. The catalyst composition of claim 1, which catalyzes the polymerization reaction of cyclic monomers but inhibits depolymerization reactions in the polymer that is the product of ring-opening polymerization.

3. 2. The catalyst composition according to claim 1, wherein the compound having an imidazole skeleton has a substituent selected from an optionally substituted branched alkyl group, an optionally substituted aryl group, an alkoxy group, a siloxane group, a fluoroalkyl group, and combinations thereof.

4. 2. The catalyst composition according to claim 1, wherein the compound having an imidazole skeleton has 1 to 3 phenyl groups.

5. The organic base compound has a pK of 18 or more ｂ 10. The catalyst composition of claim 1, wherein the compound has a value of 0.

1.

6. 2. The catalyst composition of claim 1, wherein the organic base compound has an imino group, a guanidine moiety, an amidine moiety, or an amino group.

7. 2. The catalyst composition according to claim 1, wherein the molar ratio of the organic base compound to the compound having an imidazole skeleton is in the range of 100:1 to 1:

100.

8. 2. The catalyst composition according to claim 1, wherein the organic base compound and the compound having an imidazole skeleton are present in the form of a salt.

9. The catalyst composition according to claim 1, wherein the compound having an imidazole skeleton comprises a structure that functions as a polymerization initiator.

10. A ring-opening polymerization method in which polymerization proceeds by ring-opening of a cyclic monomer, A process comprising carrying out a polymerization reaction in the presence of the catalyst composition of any one of claims 1 to 9.

11. 11. The method of claim 10, comprising catalyzing the polymerization reaction of the cyclic monomer but suppressing depolymerization reactions in the polymer that is the product of the ring-opening polymerization.

12. 11. The method of claim 10, wherein the polymer that is the product of the ring-opening polymerization has a molecular weight distribution of D<1.

5.

13. A ring-opening polymer having a structure represented by the following formula (1) or (2): 【Chemistry 1】 【Chemistry 2】 (In the formula, A １ , A ２ , B １ , B ２ , C １ , and C ２ are each independently a substituent selected from a hydrogen atom, a halogen atom, an alkyl group, a halogen-substituted alkyl group, an alkenyl group, a halogen-substituted alkenyl group, an aryl group, a halogen-substituted aryl group, an alkoxy group, a siloxane group, a fluoroalkyl group, and a combination thereof, and X is an optional polymer chain.

14. 14. The ring-opening polymer of claim 13, wherein X is a polydimethylsiloxane chain.

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