Catalyst composition, polycarbonate, and method for producing polycarbonate.

Abstract

The present invention aims to provide a catalyst composition that yields a polycarbonate with high molecular weight and excellent heat resistance, a polycarbonate with excellent heat resistance, and a method for producing polycarbonate. [Solution] A catalyst composition comprising a cerium complex represented by a specific formula (1) or (2) and a one-electron reducing agent, a method for producing a polycarbonate comprising the step of ring-opening polymerization of a cyclic carbonate using the catalyst composition, and a specific polycarbonate.

Description

[Technical Field]

[0001] This invention relates to a catalyst composition, polycarbonate, and a method for producing polycarbonate. [Background technology]

[0002] Among polycarbonates, aliphatic polycarbonates, especially those with an alicyclic structure, are excellent in terms of impact resistance, lightness, optical properties, and light resistance, and in recent years, their application in medical materials, engineering plastics, optical materials, and other fields has been actively developed.

[0003] One of the main polymerization methods for alicyclic polycarbonates is ring-opening polymerization of cyclic carbonates. Various catalysts and polymerization processes are used in this polymerization method, but the selection of the catalyst system is an important factor contributing to the properties of the resulting polycarbonate.

[0004] Among alicyclic polycarbonates, poly(cyclohexene carbonate), which has a cyclohexane carbonate structure, is the simplest polycarbonate having a saturated six-membered carbon ring corresponding to the benzene ring. For example, as described in Patent Documents 1 and 2, and Non-Patent Documents 1 and 2, it is known that poly(cyclohexene carbonate) can be obtained by ring-opening polymerization of 1,2-cyclohexene carbonate.

[0005] Furthermore, polycarbonates synthesized using not only petroleum raw materials but also biomass-derived raw materials, which are renewable resources, are being actively developed from the perspective of reducing environmental impact. Inositols, which have an alicyclic skeleton with six hydroxyl groups, are cyclic polyhydric alcohols obtained from biomass resources. Taking myo-inositol as an example, it can be used as a diol monomer for alicyclic polycarbonates by modifying and protecting four of the six hydroxyl groups. For example, Patent Document 3 reports that polycarbonates can be obtained by ring-opening polymerization of five-membered ring carbonates derived from 1,2-diol derivatives of inositols. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 7284296 [Patent Document 2] Japanese Patent Publication No. 2019-108547 [Patent Document 3] Japanese Patent Publication No. 2022-134073 [Non-patent literature]

[0007] [Non-Patent Document 1] Macromolecules 2014, 47, 4230-4235. [Non-Patent Document 2] Polymer Journal 2013, 45, 1183-1187. [Overview of the project] [Problems that the invention aims to solve]

[0008] However, when the inventors conducted a detailed investigation and examination of conventional polymerization catalysts and polycarbonates, including those described in the above-mentioned literature, they found that the catalytic activity and the heat resistance of the resulting polycarbonates were insufficient.

[0009] For example, Patent Document 1 describes the ring-opening polymerization of 1,2-cyclohexene carbonate using potassium tert-butoxide and benzyl alcohol as catalysts.

[0010] Furthermore, Patent Document 2 and Non-Patent Document 2 describe ring-opening polymerization of 1,2-cyclohexene carbonate at temperatures above 60°C, using catalysts such as zinc complexes or yttrium complexes combined with alcohols, TBD (1,5,7-triazabicyclo[4.4.0]deca-5-ene), or DBU (1,8-diazabicyclo[5.4.0]-7-undecene) combined with alcohols.

[0011] However, in order to obtain a polymer with a higher molecular weight, from the perspective of the ceiling temperature during polymerization of 1,2-cyclohexene carbonate, it is considered desirable that the catalyst used for polymerization has activity that allows the reaction to proceed even at 40°C or lower.

[0012] In addition, since thermal decomposition of polycyclohexene carbonate starts from terminal hydroxyl groups, it is considered preferable to synthesize a polymer without using an alcohol that generates terminal hydroxyl groups during ring-opening polymerization or a corresponding metal salt thereof.

[0013] Patent Document 1 describes copolymerization of a 5-membered cyclic carbonate derived from a 1,2-diol derivative of myo-inositol and poly(1,2-cyclohexene carbonate) using potassium tert-butoxide as a catalyst, but the proportion of the 5-membered cyclic carbonate derived from the 1,2-diol derivative of myo-inositol in the copolymer and the molecular weight of the obtained polymer remain low.

[0014] In addition, Patent Document 3 describes ring-opening polymerization of a 5-membered cyclic carbonate derived from a 1,2-diol derivative of myo-inositol using DBU (1,8-diazabicyclo[5.4.0]-7-undecene) as a catalyst, but both the molecular weight and heat resistance of the obtained polymer are insufficient.

[0015] The reason why a high molecular weight product cannot be obtained includes that the reaction is difficult to proceed due to the influence of the steric bulk of substituents around the carbonate group of the 5-membered cyclic carbonate derived from a 1,2-diol derivative of myo-inositol.

[0016] The present invention has been made in view of the above problems, and an object of the present invention is to provide a catalyst composition capable of obtaining a polycarbonate having a high molecular weight and excellent heat resistance, a polycarbonate excellent in heat resistance, and a method for producing a polycarbonate. [Means for Solving the Problems]

[0017] The inventors of the present invention conducted diligent research to solve the above problems. As a result, they found that the above problems could be solved by using a catalyst composition having the following configuration, and thus completed the present invention.

[0018] In other words, the present invention is as follows:

[0019] [1] A catalyst composition comprising a cerium complex represented by the following general formula (1) or (2) and a one-electron reducing agent. [ka] [ka] (In formulas (1) and (2), R1, R2, R1', R2', X1, X2, X3, X4, X5, X6, X7, X8, Y1, and Y2 independently represent a hydrogen atom, a linear, branched, or cyclic saturated or unsaturated C1-C10 alkyl group, a linear, branched, or cyclic saturated or unsaturated C1-C10 alkoxy group, a C6-C40 aryl group, a halogen atom, a hydroxyl group, an aldehyde group, a carboxyl group, an amino group, a thiol group, a nitro group, a cyano group, or an amide structure, carbonyl structure, ether structure, ester structure, phosphine structure, silyl structure, or sulfonyl structure having a linear, branched, or cyclic saturated or unsaturated C1-C10 alkyl group, where n is an integer of 0, 1, or 2.) [2] In formula (1) or (2) above X2 and X6 are independently a t-butyl group or an isopropyl group. X4 and X8 are independently a hydrogen atom, a methyl group, an isopropyl group, or a t-butyl group. Y1 and Y2 are hydrogen atoms, R1, R2, R1', R2', X2, X3, X6 and X7 are independently selected from the group consisting of a hydrogen atom, a linear, branched, or cyclic saturated or unsaturated C1-C10 alkyl group, a linear, branched, or cyclic saturated or unsaturated C1-C10 alkoxy group, a C6-C40 aryl group, a halogen atom, a hydroxyl group, an aldehyde group, a carboxyl group, an amino group, a thiol group, a nitro group, a cyano group, or an amide structure, carbonyl structure, ether structure, ester structure, phosphine structure, silyl structure, or sulfonyl structure having a linear, branched, or cyclic saturated or unsaturated C1-C10 alkyl group. The catalyst composition according to [1], wherein the one-electron reducing agent is any of bis(cyclopentadienyl)cobalt(II), bis(pentamethylcyclopentadienyl)cobalt(II), samarium(II)iodide, sodium naphthalenide, metallic sodium, or metallic lithium. [3] In formula (1) or (2) above X2 and X6 are t-butyl groups, X4 and X8 are independently a hydrogen atom, a methyl group, or a t-butyl group. Y1 and Y2 are hydrogen atoms, The catalyst composition according to [1], wherein R1, R2, R1', R2', X2, X3, X6, and X7 are independently selected from the group consisting of a hydrogen atom and a linear, branched, or cyclic saturated or unsaturated alkyl group having 1 to 10 carbon atoms, and the one-electron reducing agent is bis(cyclopentadienyl)cobalt(II), bis(pentamethylcyclopentadienyl)cobalt(II), or samarium(II)iodide. [4] In formula (1) or (2) above X2 and X6 are t-butyl groups, X4 and X8 are independently a hydrogen atom, a methyl group, or a t-butyl group. R1, R2, R1', R2', X2, X3, X6, X7, Y1 and Y2 are hydrogen atoms, The catalyst composition according to [1], wherein the one-electron reducing agent is either bis(cyclopentadienyl)cobalt(II) or bis(pentamethylcyclopentadienyl)cobalt(II). [5] A polycarbonate containing 50 mol% to 100 mol% of the structural unit represented by the following general formula (3), and having a weight-average molecular weight Mw of 30,000 to 500,000. [ka] (In formula (3), R3 and R4 are each independently a hydrogen atom, an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, an aromatic alkyl group having 7 to 30 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an acyl group having 1 to 11 carbon atoms, or an aryl group having 6 to 30 carbon atoms, and at least one of R3 and R4 is an alkyl group having 8 or more carbon atoms, and OR3 and OR4 may be bonded to each other via an alkylene group or a carbonyl group to form a cyclic structure, and the alkylene group may be substituted with a hydroxyl group, a phosphate group, an amino group, an alkoxy group, or an ester group, and a carbonyl group may be inserted into the main chain, and n is the number of repeating units.) [6] The polycarbonate according to [5], which contains 80 mol% or more and 100 mol% or less of the structural unit represented by formula (3) above, and has a weight-average molecular weight Mw of 50,000 or more and 500,000 or less. [7] The polycarbonate according to [5], which contains 100 mol% of the structural unit represented by formula (3) and has a weight-average molecular weight Mw of 70,000 or more and 500,000 or less. [8] A polycarbonate having a weight-average molecular weight Mw of 50,000 or more and 500,000 or less, an absolute molecular weight of 50,000 or more and 650,000 or less as measured by size-removal chromatography, low-angle light scattering detector (LALS), and right-angle light scattering detector (RALS), with an average intrinsic viscosity (η) of 0.5 or more and 4.0 or less, and containing a repeating structure represented by the following formula (4). [ka] (In equation (4), n is the number of repeating units.) [9] The polycarbonate according to [8], wherein the weight-average molecular weight Mw is 50,000 or more and 500,000 or less, and the average intrinsic viscosity (η) of the absolute molecular weight is 50,000 or more and 650,000 or less is 1.0 or more and 3.5 or less.

[10] A method for producing polycarbonate, comprising the step of ring-opening polymerization of a cyclic carbonate using a catalyst composition described in any of [1] to [4].

[11] The method for producing the cyclic carbonate according to

[10] , wherein the structure of the cyclic carbonate is represented by the following general formula (5) or (6), and a catalyst composition according to any one of [1] to [4] is used in a quantity of 1 / 100 of a mole percent or less relative to the cyclic carbonate. [ka] (In formula (5), R5 and R6 are each independently a hydrogen atom, an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, an aromatic alkyl group having 7 to 30 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an acyl group having 1 to 11 carbon atoms, or an aryl group having 6 to 30 carbon atoms, and at least one of R5 and R6 is an alkyl group having 8 or more carbon atoms, and OR5 and OR6 may be bonded to each other via an alkylene group or a carbonyl group to form a cyclic structure, and the alkylene group may be substituted with a hydroxyl group, a phosphate group, an amino group, an alkoxy group, or an ester group, and a carbonyl group may be inserted into the main chain.) [ka] [Effects of the Invention]

[0020] According to the present invention, a catalyst composition can be obtained that yields a polycarbonate with high molecular weight and excellent heat resistance, and a polycarbonate with excellent heat resistance can be provided. [Brief explanation of the drawing]

[0021] [Figure 1] Figure 1 is a model diagram of a single-crystal X-ray structure showing an example of the three-dimensional structure of a complex contained in the catalyst composition of the present invention. [Figure 2] The 1H-NMR spectrum of polycarbonate in Example B-1 is shown. [Modes for carrying out the invention]

[0022] The following describes in detail embodiments for carrying out the present invention (hereinafter also referred to as "this embodiment"). It should be noted that the present invention is not limited to this embodiment and can be implemented in various modifications within the scope of its gist.

[0023] [Catalyst composition] The catalyst composition of this embodiment is a catalyst composition comprising a cerium complex represented by the following general formula (1) or (2) (hereinafter also referred to as "pre-catalyst") and a one-electron reducing agent. [ka] [ka]

[0024] By adopting this configuration, the catalyst composition of this embodiment yields a polycarbonate with high molecular weight and excellent heat resistance.

[0025] The catalyst composition of this embodiment exhibits catalytic activity by reducing a cerium complex represented by formula (1) or (2), which serves as a pre-catalyst, with a one-electron reducing agent. Cerium, the central metal of the pre-catalyst, is a type of lanthanide and is characterized by a large atomic radius and high oxygen affinity. It is believed that by reacting these with a one-electron reducing agent, the valence of cerium is reduced from tetravalent to trivalent, further increasing its atomic radius and expanding the reaction field for polymerization, resulting in excellent catalytic activity and the production of a polycarbonate with high molecular weight and excellent heat resistance, although the factors are not limited to this.

[0026] Next, the substituents R1, R2, R1', R2', X1, X2, X3, X4, X5, X6, X7, X8, Y1, and Y2 in formula (1) or (2) of the catalyst composition of this embodiment will be described.

[0027] In formulas (1) and (2), R1, R2, R1', R2', X1, X2, X3, X4, X5, X6, X7, X8, Y1, and Y2 independently represent a hydrogen atom, a linear, branched, or cyclic saturated or unsaturated C1-C10 alkyl group, a linear, branched, or cyclic saturated or unsaturated C1-C10 alkoxy group, a C6-C40 aryl group, a halogen atom, a hydroxyl group, an aldehyde group, a carboxyl group, an amino group, a thiol group, a nitro group, a cyano group, or an amide structure, carbonyl structure, ether structure, ester structure, phosphine structure, silyl structure, or sulfonyl structure having a linear, branched, or cyclic saturated or unsaturated C1-C10 alkyl group, where n is an integer of 0, 1, or 2.

[0028] The linear, branched, or cyclic saturated alkyl group having 1 to 10 carbon atoms is not particularly limited, but examples include methyl group, ethyl group, n-propyl group, 2-propyl group, n-butyl group, isobutyl group, t-butyl group, n-pentyl group, 1-ethylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 2,2-dimethylpropyl group, 1,1-dimethylpropyl group, n-hexyl group, 1-ethylbutyl group, 2-ethylbutyl group, 3-ethylbutyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4 -Methylpentyl group, 1,1-dimethylbutyl group, 2,2-dimethylbutyl group, 3,3-dimethylbutyl group, 1,2-dimethylbutyl group, 1,3-dimethylbutyl group, 2,3-dimethylbutyl group, n-heptyl group, 1-methylhexyl group, 2-methylhexyl group, 3-methylhexyl group, 4-methylhexyl group, 5-methylhexyl group, 1-ethylpentyl group, 2-ethylpentyl group, 3-ethylpentyl group, 1,1-dimethylpentyl group, 2,2-dimethylpentyl group, 3,3-dimethylpentyl group, 4,4-dimethylpentyl group, 1,2-dimethyl Pentyl group, 1,3-dimethylpentyl group, 1,4-dimethylpentyl group, 2,3-dimethylpentyl group, 2,4-dimethylpentyl group, 3,4-dimethylpentyl group, 2-methyl-3,3-dimethylbutyl group, 1-methyl-3,3-dimethylbutyl group, 1,2,3-trimethylbutyl group, 1,3-dimethyl-2-pentyl group, 2-isopropylbutyl group, n-octyl group, 2-octyl group, 3-octyl group, 4-octyl group, 2-methylheptyl group, 3-methylheptyl group, 4-methylheptyl group, 5-methylheptyl group, 6-methylheptyl group , 2-ethylhexyl group, 3-ethylhexyl group, 4-ethylhexyl group, 5-ethylhexyl group, 1,1-dimethylhexyl group, 2,2-dimethylhexyl group, 3,3-dimethylhexyl group, 4,4-dimethylhexyl group, 5,5-dimethylhexyl group, 1,2-dimethylhexyl group, 1,3-dimethylhexyl group, 1,4-dimethylhexyl group, 1,5-dimethylhexyl group, 2,3-dimethylhexyl group, 2,4-dimethylhexyl group, 2,5-dimethylhexyl group, 1,1-ethylmethylpentyl group, 2,2-ethylmethylpentyl group, 3,3-ethylmethylpentyl group, 4,4-ethylmethylpentyl group, 1-ethyl-2-methylpentyl group, 1-ethyl-3-methylpentyl group, 1-ethyl-4-methylpentyl group, 2-ethyl-1-methylpentyl group, 3-ethyl-1-methylpentyl group, 4-ethyl-1-methylpentyl group, 2-ethyl-3-methylpentyl group, 2-ethyl-4-methylpentyl group, 3-ethyl-2-methylpentyl group, 4-ethyl-3-methylpentyl group, 3-ethyl-4-methylpentyl group, 4-ethyl-3-methylpentyl group, 1-(2-methylpropyl)butyl group, 1-(2-methylpropyl)-2-methylbutyl group, 1,1-(2-methylpropyl)ethyl group, 1,1-(2-methylpropyl)ethylpropyl group, 1,1-diethylpropyl group, 2,2-diethylpropyl group, 1,1-ethylmethyl-2,2-dimethylpropyl group Examples include 2,2-ethylmethyl-1,1-dimethylpropyl group, 2-ethyl-1,1-dimethylbutyl group, nonyl group, isononyl group, decyl group, isodecyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, 2-ethylcyclopentyl group, 3-ethylcyclopentyl group, 2,3-dimethylcyclopentyl group, 2,4-dimethylcyclopentyl group, 1-methylcyclohexyl group, 2-methylcyclohexyl group, 3-methylcyclohexyl group, 4-methylcyclohexyl group, 2,3-dimethylcyclohexyl group, 2,3-dimethylcyclohexyl group, 2,5-dimethylcyclohexyl group, 2,6-dimethylcyclohexyl group, 3,5-dimethylcyclohexyl group, 2-ethylcyclohexyl group, 3-ethylcyclohexyl group, and 4-ethylcyclohexyl group. From the viewpoint of achieving the effects of the present invention more effectively and reliably, when R1, R2, R1', R2', X1, X2, X3, X4, X5, X6, X7 and X8 in formula (1) or (2) are linear, branched, or cyclic saturated alkyl groups having 1 to 10 carbon atoms, preferably methyl group, ethyl group, n-propyl group, 2-propyl group, n-butyl group, isobutyl group, t-butyl group, n-pentyl group, 1-ethylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 2,2-dimethylpropyl group, 1,1-dimethylpropyl group, n-hexyl group, 1-ethylbutyl group, 2-ethylbutyl group, 3-ethylbutyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, 1,1-dimethylbutyl group, 2,2-dimethylbutyl group, 3,3-dimethylbutyl group, 1,2-dimethylbutyl group, 1,3-dimethylbutyl group, 2,3-dimethylbutyl group, more preferably methyl group, ethyl group, n-propyl group, 2-propyl group, n-butyl group, isobutyl group, t-butyl group, n-pentyl group, 1-ethylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 2,2-dimethylpropyl group, 1,1-dimethylpropyl group, and even more preferably methyl group, ethyl group, n-propyl group, 2-propyl group, n-butyl group, isobutyl group, t-butyl group.

[0029] A linear, branched, or cyclic unsaturated alkyl group having 1 to 10 carbon atoms represents a hydrocarbon group in which a portion of the alkyl group is represented by an unsaturated bond. Examples include, but are not limited to, vinyl group, 1-propenyl group, allyl group, 2-butenyl group, 3-butenyl group, 4-pentenyl group, 5-hexenyl group, 6-heptenyl group, 7-octenyl group, 8-nonenyl group, and 9-decenyl group. From the viewpoint of achieving the effects of the present invention more effectively and reliably, when R1, R2, R1', R2', X1, X2, X3, X4, X5, X6, X7, and X8 in formula (1) or (2) are linear, branched, or cyclic unsaturated alkyl groups having 1 to 10 carbon atoms, they are preferably vinyl groups, 1-propenyl groups, allyl groups, 2-butenyl groups, 3-butenyl groups, more preferably vinyl groups, allyl groups, 3-butenyl groups, and even more preferably vinyl groups and allyl groups.

[0030] The structure of the hydrocarbon with a linear, branched, or cyclic saturated or unsaturated alkoxy group having 1 to 10 carbon atoms is the same as that of the linear, branched, or cyclic saturated or unsaturated alkyl groups described above, and the preferred groups are also the same.

[0031] The structures of linear, branched, or cyclic saturated or unsaturated C1-C10 alkyl groups in amide, carbonyl, ether, ester, phosphine, silyl, and sulfonyl structures are the same as those of linear, branched, or cyclic saturated or unsaturated alkyl groups described above, and the preferred groups are also the same.

[0032] The aryl group having 6 to 40 carbon atoms is not particularly limited, but examples include phenyl, tolyl, naphthyl, biphenyl, phenanthryl, and anthracenyl groups. Furthermore, at least one hydrogen atom in these aryl groups may be substituted with a linear, branched, or cyclic saturated or unsaturated alkyl group as defined above.

[0033] In formula (1) or (2) above, preferably, among R1, R2, R1', R2', X1, X2, X3, X4, X5, X6, X7, X8, Y1 and Y2, X2 and X6 are independently a t-butyl group or an isopropyl group, X4 and X8 are independently a hydrogen atom, a methyl group, an isopropyl group, or a t-butyl group, Y1 and Y2 are each a hydrogen atom, and R1, R2, R1', R2', X2, X3, X6 and X7 are independently a hydrogen atom, a linear, branched, or cyclic saturated or unsaturated carbon The structure is selected from the group consisting of an alkyl group having prime numbers 1 to 10, a linear, branched, or cyclic saturated or unsaturated alkoxy group having 1 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, a halogen atom, a hydroxyl group, an aldehyde group, a carboxyl group, an amino group, a thiol group, a nitro group, a cyano group, or an amide structure, carbonyl structure, ether structure, ester structure, phosphine structure, silyl structure, or sulfonyl structure having a linear, branched, or cyclic saturated or unsaturated alkyl group having 1 to 10 carbon atoms. The definitions and preferred embodiments of the alkyl group, alkoxy group, aryl group, amide structure, carbonyl structure, ether structure, ester structure, phosphine structure, silyl structure, or sulfonyl structure are the same as described above.

[0034] In formula (1) or (2) above, more preferably, among R1, R2, R1', R2', X1, X2, X3, X4, X5, X6, X7, X8, Y1 and Y2, X2 and X6 are each t-butyl groups, X4 and X8 are independently a hydrogen atom, a methyl group, or a t-butyl group, Y1 and Y2 are each hydrogen atoms, and R1, R2, R1', R2', X2, X3, X6 and X7 are independently a hydrogen atom and a structure selected from the group consisting of a linear, branched, or cyclic saturated or unsaturated alkyl group having 1 to 10 carbon atoms. The definition and preferred embodiments of this alkyl group are the same as described above.

[0035] In formula (1) or (2) above, more preferably, among R1, R2, R1', R2', X1, X2, X3, X4, X5, X6, X7, X8, Y1 and Y2, X2 and X6 are t-butyl groups, X4 and X8 are independently a hydrogen atom, a methyl group, or a t-butyl group, and R1, R2, R1', R2', X2, X3, X6, X7, Y1 and Y2 are hydrogen atoms.

[0036] The method for producing the cerium complex represented by formula (1) or (2) is not particularly limited, but examples include reacting a tetravalent cerium complex, such as a cerium(IV) alkoxide complex, with the corresponding salen ligand, or reacting cerium(III) chloride with the corresponding salen complex and oxidizing it in air. From the viewpoint of raw material availability, the reaction using cerium(III) chloride is more preferable.

[0037] (One-electron reducing agent) The cerium complex represented by formula (1) or (2) above is catalytically activated by combining it with a one-electron reducing agent (hereinafter also referred to as an activated cocatalyst). In this embodiment, the term "one-electron reducing agent" refers to a reducing agent that reduces the valence of the cerium complex from tetravalent to trivalent. The one-electron reducing agent suitable for use in this embodiment is not particularly limited as long as it can reduce the valence of the cerium complex from tetravalent to trivalent, but is preferably bis(cyclopentadienyl)cobalt(II), bis(pentamethylcyclopentadienyl)cobalt(II), samarium(II)iodide, sodium naphthalenide, metallic sodium, or metallic lithium, more preferably bis(cyclopentadienyl)cobalt(II), bis(pentamethylcyclopentadienyl)cobalt(II), or samarium(II)iodide, and even more preferably bis(cyclopentadienyl)cobalt(II) or bis(pentamethylcyclopentadienyl)cobalt(II).

[0038] In the catalyst composition of this embodiment, the content ratio of the one-electron reducing agent is preferably 1 to 10 equivalents, more preferably 1 to 5 equivalents, and even more preferably 1 to 3 equivalents, relative to the pre-catalyst.

[0039] [First Polycarbonate] The first polycarbonate of this embodiment contains 50% to 100% of structural units represented by the following general formula (3), and has a weight-average molecular weight Mw of 30,000 to 500,000. The first polycarbonate of this embodiment has excellent heat resistance due to these characteristics.

[0040] The first polycarbonate in this embodiment is preferably derived from myo-inositol. Furthermore, the first polycarbonate in this embodiment is preferably 10% weight loss temperature of 280°C or higher. [ka] (In formula (3), R3 and R4 are each independently a hydrogen atom, an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, an aromatic alkyl group having 7 to 30 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an acyl group having 1 to 11 carbon atoms, or an aryl group having 6 to 30 carbon atoms, and at least one of R3 and R4 is an alkyl group having 8 or more carbon atoms, and OR3 and OR4 may be bonded to each other via an alkylene group or a carbonyl group to form a cyclic structure, and the alkylene group may be substituted with a hydroxyl group, a phosphate group, an amino group, an alkoxy group, or an ester group, and a carbonyl group may be inserted into the main chain, and n is the number of repeating units.)

[0041] The first polycarbonate of this embodiment has an inositol skeleton as shown in formula (3) above, and therefore has a high biomass resource content, which can reduce the environmental burden. Generally, the thermal decomposition of polymers is caused by pericyclic reactions and ring-closing reactions resulting from molecular motion in the main chain and terminals at high temperatures. In the first polycarbonate of this embodiment, all four carbon atoms in the cyclohexane ring of formula (3) that are not intermolecularly linked by carbonate groups have substituents, and it is thought that the aforementioned reactions are less likely to occur due to the effect of this bulkiness, resulting in excellent heat resistance, but the factors are not limited to this.

[0042] In this embodiment, the inositol skeleton refers to the skeleton represented by the following formula (7) derived from 1,2,3,4,5,6-hexahydroxycyclohexane, and compounds containing this skeleton are called inositols. [ka]

[0043] The inositol skeleton is derived from biomass-derived inositols, including myo-inositol. Despite being biomass-derived, inositols do not contain heteroatoms such as oxygen or nitrogen in their alicyclic skeleton, resulting in excellent transparency, heat resistance, and color tone, while also providing well-balanced properties such as low water absorption and high thermal stability.

[0044] The inositols used in this embodiment are not particularly limited as long as they can form the structure of formula (7) above, but examples include allo-inositol, chiro-inositol, cis-inositol, epi-inositol, myo-inositol, muco-inositol, neo-inositol, and scyllo-inositol, and myo-inositol, represented by the following formula (8), is preferred from the viewpoint of availability. [ka]

[0045] In the synthesis of the first polycarbonate of this embodiment, inositol may be used as a raw material, or an inositol derivative such as a methyl ester of inositol or a phosphate ester of phytic acid may be used as a raw material. Such an inositol derivative is not particularly limited as long as it can form the structure of formula (7) above, but examples include bornesitol, pinitol, ononitol, pinpolitol, and quebranthol (quebrachitol).

[0046] The substituents R3 and R4 in formula (3) will be explained below.

[0047] In formula (3) above, R3 and R4 are each independently a hydrogen atom, an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, an aromatic alkyl group having 7 to 30 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an acyl group having 1 to 11 carbon atoms, or an aryl group having 6 to 30 carbon atoms, and at least one of R3 and R4 is an alkyl group having 8 or more carbon atoms, and OR3 and OR4 may be bonded to each other via an alkylene group or a carbonyl group to form a cyclic structure, and the alkylene group may be substituted with a hydroxyl group, a phosphate group, an amino group, an alkoxy group, or an ester group, and a carbonyl group may be inserted into the main chain, and n is the number of repeating units. In formula (3), n is preferably 2 to 20, more preferably 4 to 14, and even more preferably 6 to 12.

[0048] The unsubstituted linear or branched C1-C10 alkyl group is not particularly limited, but examples include methyl group, ethyl group, n-propyl group, 2-propyl group, n-butyl group, isobutyl group, t-butyl group, n-pentyl group, 1-ethylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 2,2-dimethylpropyl group, 1,1-dimethylpropyl group, n-hexyl group, 1-ethylbutyl group, 2-ethylbutyl group, 3-ethylbutyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl 1,1-dimethylbutyl group, 2,2-dimethylbutyl group, 3,3-dimethylbutyl group, 1,2-dimethylbutyl group, 1,3-dimethylbutyl group, 2,3-dimethylbutyl group, n-heptyl group, 1-methylhexyl group, 2-methylhexyl group, 3-methylhexyl group, 4-methylhexyl group, 5-methylhexyl group, 1-ethylpentyl group, 2-ethylpentyl group, 3-ethylpentyl group, 1,1-dimethylpentyl group, 2,2-dimethylpentyl group, 3,3-dimethylpentyl group, 4,4-dimethylpentyl group, 1,2-dimethylpentyl group, 1,3 -dimethylpentyl group, 1,4-dimethylpentyl group, 2,3-dimethylpentyl group, 2,4-dimethylpentyl group, 3,4-dimethylpentyl group, 2-methyl-3,3-dimethylbutyl group, 1-methyl-3,3-dimethylbutyl group, 1,2,3-trimethylbutyl group, 1,3-dimethyl-2-pentyl group, 2-isopropylbutyl group, n-octyl group, 2-octyl group, 3-octyl group, 4-octyl group, 2-methylheptyl group, 3-methylheptyl group, 4-methylheptyl group, 5-methylheptyl group, 6-methylheptyl group, 2-ethylhexyl group, 3 -Ethylhexyl group, 4-ethylhexyl group, 5-ethylhexyl group, 1,1-dimethylhexyl group, 2,2-dimethylhexyl group, 3,3-dimethylhexyl group, 4,4-dimethylhexyl group, 5,5-dimethylhexyl group, 1,2-dimethylhexyl group, 1,3-dimethylhexyl group, 1,4-dimethylhexyl group, 1,5-dimethylhexyl group, 2,3-dimethylhexyl group, 2,4-dimethylhexyl group, 2,5-dimethylhexyl group, 1,1-ethylmethylpentyl group, 2,2-ethylmethylpentyl group, 3,3-ethylmethylpentyl group, 4,4-ethylmethylpentyl group, 1-ethyl-2-methylpentyl group, 1-ethyl-3-methylpentyl group, 1-ethyl-4-methylpentyl group, 2-ethyl-1-methylpentyl group, 3-ethyl-1-methylpentyl group, 4-ethyl-1-methylpentyl group, 2-ethyl-3-methylpentyl group, 2-ethyl-4-methylpentyl group, 3-ethyl-2-methylpentyl group, 4-ethyl-3-methylpentyl group, 3-ethyl-4-methylpentyl group, 4-ethyl-3-methylpentyl Examples include the group, 1-(2-methylpropyl)butyl group, 1-(2-methylpropyl)-2-methylbutyl group, 1,1-(2-methylpropyl)ethyl group, 1,1-(2-methylpropyl)ethylpropyl group, 1,1-diethylpropyl group, 2,2-diethylpropyl group, 1,1-ethylmethyl-2,2-dimethylpropyl group, 2,2-ethylmethyl-1,1-dimethylpropyl group, 2-ethyl-1,1-dimethylbutyl group, nonyl group, isononyl group, decyl group, isodecyl group, etc.

[0049] The unsubstituted cyclic alkyl groups having 1 to 10 carbon atoms are not particularly limited, but examples include unsubstituted cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups; substituted cyclopentyl groups such as 2-ethylcyclopentyl, 3-ethylcyclopentyl, 2,3-dimethylcyclopentyl, and 2,4-dimethylcyclopentyl groups; and substituted cyclohexyl groups such as 1-methylcyclohexyl, 2-methylcyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, 2,3-dimethylcyclohexyl, 2,5-dimethylcyclohexyl, 2,6-dimethylcyclohexyl, 3,5-dimethylcyclohexyl, 2-ethylcyclohexyl, 3-ethylcyclohexyl, and 4-ethylcyclohexyl groups.

[0050] The aromatic alkyl group having 7 to 30 carbon atoms is not particularly limited, but may have substituents on the aromatic ring. Examples include benzyl groups, methoxybenzyl groups, and ethoxybenzyl groups.

[0051] The alkenyl group having 2 to 10 carbon atoms is not particularly limited, but for example, it represents a linear, branched, or cyclic hydrocarbon group in which part of the alkyl group is represented by an unsaturated bond. Specifically, although not particularly limited, examples include vinyl group, 1-propenyl group, allyl group, 2-butenyl group, 3-butenyl group, 4-pentenyl group, 5-hexenyl group, 6-heptenyl group, 7-octenyl group, 8-nonenyl group, 9-decenyl group, etc.

[0052] The acyl group having 1 to 11 carbon atoms is not particularly limited, but examples include the formyl group, acetyl group, propionyl group, butyryl group, valeryl group, and benzoyl group.

[0053] When the above acyl group is present, OR3 and OR4 mean that they have a carbonate structure ((-OC(=O)O- group)).

[0054] The aryl group having 6 to 30 carbon atoms is not particularly limited, but examples include the phenyl group, tolyl group, xylyl group, trimethylphenyl group, coumenyl group, biphenyl group, naphthyl group, etc.

[0055] Furthermore, preferably at least one of R3 and R4 is an alkyl group having 8 or more carbon atoms (C8 or more), and more preferably both R3 and R4 are alkyl groups having 8 or more carbon atoms (C8 or more). The alkyl group having 8 or more carbon atoms (C8 or more) is preferably a linear alkyl group having 8 or more carbon atoms (C8 or more).

[0056] R3 and R4 may be bonded to each other via an alkylene group or a carbonate group (-OC(=O)O- group) to form a cyclic structure, and the alkylene group may be substituted with a hydroxyl group, a phosphate group, an amino group, an alkoxy group, or an ester group, and a carbonyl group may be inserted into the main chain. From the viewpoint of more reliably and effectively achieving the effects of the present invention, when R3 and R4 are bonded to each other via an alkylene group to form a cyclic structure, the number of carbon atoms in the alkylene group is preferably 1 to 10, more preferably 1 to 8, and even more preferably 1 to 6. Furthermore, from the same viewpoint, the substituents on the alkylene group are preferably a hydroxyl group, an alkoxy group, or an ester group, and more preferably a hydroxyl group or an alkoxy group. From the same viewpoint, when R3 and R4 form a cyclic structure, it is preferably formed via an unsubstituted alkylene group or a carbonate group (-OC(=O)O- group). Examples of unsubstituted alkylene groups include methylene, ethylene, n-propylene, n-butylene, n-pentylene, and n-hexylene groups.

[0057] The aforementioned phosphate group and amino group may be unsubstituted or substituted. That is, they may be monosubstituted or disubstituted. From the viewpoint of achieving the effects of the present invention more effectively and reliably, when the phosphate group and amino group are substituted, the substituent is preferably an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms. From a similar viewpoint, the phosphate group and amino group in this embodiment are preferably unsubstituted.

[0058] In the first polycarbonate of this embodiment, the weight-average molecular weight (Mw) measured by size exclusion chromatography (SEC) using polystyrene as a standard sample is preferably 30,000 to 500,000, more preferably 50,000 to 500,000, and even more preferably 70,000 to 500,000. When using conventional catalysts, polymerization of myo(myo)-inositol-derived monomers presents challenges: (1) high molecular weight polymers cannot be obtained through homopolymerization, and (2) even in copolymerization, it is difficult to increase the content of myo(myo)-inositol-derived monomers in the resulting polymer or to achieve high molecular weight polymers. However, by utilizing the catalyst composition of this embodiment, it has become possible for the first time to synthesize polymers in which myo(myo)-inositol-derived monomer units (structural units) are 50 mol% or more and the weight-average molecular weight (Mw) is 30,000 or more, thereby improving the thermal decomposition temperature of the resulting polymers.

[0059] In the first polycarbonate of this embodiment, the number-average molecular weight Mn, measured by size exclusion chromatography using polystyrene as a standard sample, is preferably 20,000 to 500,000, more preferably 30,000 to 400,000, and even more preferably 45,000 to 300,000. In the first polycarbonate of this embodiment, there are no particular limitations on the method for controlling the number-average molecular weight Mn within the aforementioned range, but examples include appropriately adjusting the ratio of polymerizable monomer to catalyst composition and the polymerization time. Reducing the ratio of catalyst composition to polymerizable monomer tends to increase the Mn. In addition, increasing the polymerization time also tends to increase the Mn.

[0060] In this embodiment, the weight-average molecular weight and number-average molecular weight of the polycarbonate can be measured by the method described in the examples below.

[0061] The 10% weight loss temperature of the first polycarbonate in this embodiment is preferably 280°C or higher, more preferably 290°C or higher, and even more preferably 300°C or higher, from the viewpoint of suppressing discoloration, decrease in strength, molding defects, etc., caused by main chain severance and decomposition from the ends when using the polymer. The upper limit of the 10% weight loss temperature of the first polycarbonate in this embodiment is not particularly limited, but for example, it is 450°C.

[0062] In the first polycarbonate of this embodiment, the method for controlling the 10% weight loss temperature within the above range is not particularly limited, but for example, the molecular weight of the polycarbonate can be controlled or the residual metals in the polycarbonate can be reduced. In particular, increasing the weight-average molecular weight Mw of the polycarbonate to 30,000 or more in terms of polystyrene, or reducing the amount of residual metals in the polymer through purification operations, tends to reduce the weight loss rate. In this embodiment, the 10% weight loss temperature can be measured by the method described in the examples below.

[0063] When the monomer units constituting the first polycarbonate of this embodiment are set to 100 mol%, from the viewpoint of suppressing discoloration, decrease in strength, molding defects, etc. caused by main chain severance and decomposition from the ends when using the polymer, the content of the structural unit represented by formula (3) is preferably 50 mol% or more and 100 mol% or less, more preferably 80 mol% or more and 100 mol% or less, and even more preferably 100 mol%.

[0064] The structure represented by formula (3) above may be either cis-type or trans-type, but is preferably a trans-type structure represented by the following formula (9). [ka]

[0065] When the carbonate groups of the main chain in formula (9) are at positions 1 and 2, the carbonate groups of the other side chain at positions 4 and 5 may be in either the cis or trans configuration, but are preferably in the cis configuration represented by formula (10) below. [ka]

[0066] In this embodiment, in formulas (9) and (10), if one of the two bonding portions between the cyclohexane portion and the carbonate group is a dotted line and the other is a thick solid line, it represents the trans type, and if both are dotted lines or thick solid lines, it represents the cis type.

[0067] In this embodiment, when both the cyclohexane portion and the carbonate group in the structural formula are represented by ordinary solid lines, it indicates that the compound can take either the cis or trans form. Unless otherwise specified, the main chain carbonate groups at positions 1 and 2 in formula (9) represent a compound containing (1S,2S)-trans and (1R,2R)-trans isomers in any ratio. Unless otherwise specified, the stereostructure of formula (10) represents a compound consisting of structural units made up of any combination of two types of main chain carbonate groups at positions 1 and 2: (1S,2S)-trans and (1R,2R)-trans isomers, and two types of side chain carbonate groups at positions 3 and 4: (3S,4R-)-cis and (3R,4S)-cis isomers.

[0068] In equations (9) and (10) above, R3, R4, and n are the same as those in equation (3) above.

[0069] The first polycarbonate of this embodiment may be a cyclic structure in which the terminal portions T1 and T2 in the following formula (11) are bonded to each other (single bond), that is, a cyclic structure without terminal structures, or it may be a structure in which both ends are hydroxyl groups as represented by the following formula (12). [ka] [ka]

[0070] In equations (11) and (12) above, R3, R4, and n are the same as those in equation (3) above.

[0071] In the first polycarbonate of this embodiment, in order to control the weight-average molecular weight (Mw) within the above range, the ratio of polymerizable monomer to polymerization initiator and the polymerization time can be appropriately adjusted, or the polycarbonate can be produced by the manufacturing method described later. Reducing the ratio of polymerization initiator to polymerizable monomer tends to increase the Mw. Also, increasing the polymerization time tends to increase the Mw.

[0072] [The second polycarbonate] The second polycarbonate of this embodiment (hereinafter also referred to as "poly(cyclohexane carbonate)") contains a repeating structure represented by the following formula (4), wherein the weight-average molecular weight Mw is 50,000 or more and 500,000 or less, and the average intrinsic viscosity (η) is 0.5 or more and 4.0 or less, with an absolute molecular weight of 50,000 or more and 650,000 or less, as measured by size removal chromatography, low-angle light scattering detector (LALS), and right-angle light scattering detector (RALS). [ka] (In equation (4), n is the number of repeating units.) The second polycarbonate of this embodiment has excellent heat resistance due to these characteristics. In formula (4), n is preferably between 100 and 50000, more preferably between 350 and 35000, and even more preferably between 350 and 25000.

[0073] In the poly(cyclohexane carbonate) of this embodiment, the weight-average molecular weight (Mw) measured by size exclusion chromatography (SEC) using polystyrene as a standard sample is preferably 50,000 to 500,000, more preferably 80,000 to 500,000, and even more preferably 100,000 to 500,000.

[0074] In the poly(cyclohexane carbonate) of this embodiment, the number-average molecular weight Mn, measured by size exclusion chromatography using polystyrene as a standard sample, is preferably 50,000 to 500,000, more preferably 65,000 to 400,000, and even more preferably 80,000 to 300,000.

[0075] In the poly(cyclohexane carbonate) of this embodiment, there are no particular limitations on the method for controlling the number-average molecular weight Mn within the aforementioned range, but examples include appropriately adjusting the ratio of polymerizable monomer to catalyst composition and the polymerization time. Reducing the ratio of catalyst composition to polymerizable monomer tends to increase the Mn. In addition, increasing the polymerization time also tends to increase the Mn.

[0076] In this embodiment, the weight-average molecular weight and number-average molecular weight of the polycarbonate resin can be measured by the method described in the examples below using size exclusion chromatography.

[0077] In this embodiment, the poly(cyclohexane carbonate) has a Mw within the above range, which reduces the content of low molecular weight components (mainly quantifiers) with low thermal decomposition temperatures. This is thought to suppress the acceleration of polymer chain decomposition by chemical species resulting from the decomposition of these low molecular weight components. In addition, the increased entanglement of the polymer molecular chains is thought to contribute to improved heat resistance, although the factors are not limited to this.

[0078] In the poly(cyclohexane carbonate) of this embodiment, the average intrinsic viscosity (η) of an absolute molecular weight of 50,000 to 650,000, as measured by size removal chromatography (SEC), low-angle light scattering detector (LALS), and right-angle light scattering detector (RALS), is preferably 0.5 to 4.0, more preferably 1.0 to 3.5.

[0079] In this embodiment, the absolute molecular weight and intrinsic viscosity (η) of the polycarbonate resin can be measured by the methods described in the examples below, using size removal chromatography (SEC), low-angle light scattering detector (LALS), and right-angle light scattering detector (RALS).

[0080] Generally, the lower the intrinsic viscosity (η) of a polymer, the higher its density. In this embodiment, the average intrinsic viscosity (η) within the absolute molecular weight of poly(cyclohexane carbonate) falls within the above range, which is thought to contribute to improved heat resistance by making the polymer's main chain less mobile; however, the contributing factors are not limited to this.

[0081] The 10% weight loss temperature of poly(cyclohexane carbonate) in this embodiment is preferably 280 to 320°C, and more preferably 285 to 300°C, from the viewpoint of suppressing discoloration, decrease in strength, molding defects, etc., caused by main chain severance and decomposition from the ends when using the polymer. In the poly(cyclohexane carbonate) of this embodiment, the method for controlling the 10% weight loss temperature within the above range is not particularly limited, but for example, the molecular weight of the polycarbonate can be controlled or the residual metals in the polycarbonate can be reduced. In particular, increasing the weight-average molecular weight Mw of the polycarbonate to 15,000 or more in terms of polystyrene, or reducing the residual metals in the polymer through purification operations, tends to reduce the weight loss rate. In this embodiment, the 10% weight loss temperature can be measured by the method described in the examples below.

[0082] In this embodiment, if one of the two bonding portions between the cyclohexane moiety and the carbonate group in formula (4) is represented by a dotted line and the other by a thick solid line, it represents the trans form, and unless otherwise specified, the main chain carbonate groups at positions 1 and 2 represent a compound containing (1S,2S)-trans and (1R,2R)-trans isomers in any ratio.

[0083] The poly(cyclohexane carbonate) of this embodiment may be a cyclic structure in which the terminal portions T1 and T2 are bonded to each other (single bond) in the following formula (13), that is, a cyclic structure without terminal structures, or a structure in which both ends are hydroxyl groups as represented by the following formula (14), but it is preferable that it forms a cyclic structure in which the terminal portions T1 and T2 are bonded to each other (single bond). [ka] [ka] (In equations (13) and (14), n is the number of repeating units.) In equations (13) and (14) above, n is the same as in equation (4) above.

[0084] In the poly(cyclohexane carbonate) of this embodiment, in order to control the weight-average molecular weight (Mw) and the average of the intrinsic viscosity (η) within the absolute molecular weight range to within the above range, the ratio of polymerizable monomer to polymerization initiator and the polymerization time can be appropriately adjusted, or the poly(cyclohexane carbonate) can be produced by the production method described later. Reducing the ratio of polymerization initiator to polymerizable monomer tends to increase Mw. Also, increasing the polymerization time tends to increase Mw.

[0085] [Method for manufacturing polycarbonate] The method for producing polycarbonate in this embodiment includes a step of ring-opening polymerization of a cyclic carbonate using the catalyst composition described above. According to the manufacturing method of this embodiment, the first and second polycarbonates described above can be manufactured. The method for producing polycarbonate according to this embodiment specifically includes, for example, a step of ring-opening polymerization of at least one compound selected from the group of cyclic carbonates represented by the following formulas (5) and (6) in the presence of a catalyst composition containing a cerium complex (pre-catalyst) represented by formula (1) or (2) and a one-electron reducing agent. [ka] (In formula (5), R5 and R6 are each independently a hydrogen atom, an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, an aromatic alkyl group having 7 to 30 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an acyl group having 1 to 11 carbon atoms, or an aryl group having 6 to 30 carbon atoms, and at least one of R5 and R6 is an alkyl group having 8 or more carbon atoms, and OR5 and OR6 may be bonded to each other via an alkylene group or a carbonyl group to form a cyclic structure, and the alkylene group may be substituted with a hydroxyl group, a phosphate group, an amino group, an alkoxy group, or an ester group, and a carbonyl group may be inserted into the main chain.)

[0086] In this embodiment, preferred R5 and R6 in formula (5) are the same as R3 and R4 in formula (3), respectively. Furthermore, the examples of phosphate groups, amino groups, unsubstituted linear, branched, or cyclic alkyl groups having 1 to 10 carbon atoms, aromatic alkyl groups having 7 to 30 carbon atoms, alkenyl groups having 2 to 10 carbon atoms, acyl groups having 1 to 11 carbon atoms, or aryl groups having 6 to 30 carbon atoms in formula (5) are the same as those in formula (3).

[0087] In this embodiment, unless otherwise specified, the stereostructure of the carbonate group in formula (5) represents a compound consisting of a structural unit comprising any combination of two types of main chain carbonate groups at positions 1 and 2: (1S,2S)-trans and (1R,2R)-trans, and two types of side chain carbonate groups at positions 3 and 4: (3S,4R-)-cis and (3R,4S)-cis.

[0088] [ka]

[0089] In this embodiment, unless otherwise specified, the stereostructure of the carbonate group in formula (5) represents a compound containing the (1S,2S)-trans and (1R,2R)-trans isomers in any ratio.

[0090] In the method for producing polycarbonate according to this embodiment, the structure of the cyclic carbonate is represented by formula (5) or (6), and it is preferable to use the above-mentioned catalyst composition at a concentration of 1 / 100th of a mole percent or less relative to the cyclic carbonate. In the method for producing polycarbonate according to this embodiment, the amount of the catalyst composition used is more preferably 1 / 50 to 1 / 5000 of a mole percent relative to the cyclic carbonate, and even more preferably 1 / 100 to 1 / 2500 of a mole percent.

[0091] (Catalyst composition) In the polycarbonate production method of this embodiment, the amount of the cerium complex represented by formula (1) or (2) used as a pre-catalyst is preferably 1 / 50 to 1 / 5000 equivalents, more preferably 1 / 50 to 1 / 2500 equivalents, and even more preferably 1 / 50 to 1 / 1000 equivalents relative to the raw material carbonate. To promote ring-opening polymerization, a one-electron reducing agent may be added to the reaction system, preferably in amounts of 1 to 10 equivalents, more preferably 1 to 5 equivalents, and even more preferably 1 to 3 equivalents, relative to the pre-catalyst. Within the above range, the polymerization reaction tends to proceed efficiently. The mixing order of each component is not particularly limited; for example, the one-electron reducing agent may be added to a solution of the solvent, carbonate, and pre-catalyst, or a solution containing a catalyst composition produced by separately reacting the pre-catalyst and the one-electron reducing agent may be added to the solvent and carbonate solution.

[0092] In the method for producing polycarbonate resin according to this embodiment, the one-electron reducing agent is not particularly limited, but examples include, but are not limited to, bis(cyclopentadienyl)cobalt(II), bis(pentamethylcyclopentadienyl)cobalt(II), samarium(II)iodide, sodium naphthalenide, metallic sodium, metallic lithium, etc. From the viewpoint of suppressing side reactions with the carbonate, the above one-electron reducing agent is preferably bis(cyclopentadienyl)cobalt(II), bis(pentamethylcyclopentadienyl)cobalt(II), samarium(II)iodide, sodium naphthalenide, more preferably bis(cyclopentadienyl)cobalt(II), bis(pentamethylcyclopentadienyl)cobalt(II), samarium(II)iodide, and even more preferably bis(pentamethylcyclopentadienyl)cobalt(II).

[0093] In the method for producing polycarbonate according to this embodiment, the solvent is not particularly limited, but examples include ether-based solvents such as diethyl ether, diisopropyl ether, dibutyl ether, diphenyl ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran, 1,4-dioxane, cyclopentyl methyl ether, tert-butyl methyl ether, and propylene glycol monomethyl ether acetate; halogen-based solvents such as methylene chloride, chloroform, dichloromethane, dichloroethane, and trichloroethane; saturated hydrocarbon-based solvents such as hexane, heptane, octane, nonane, cyclohexane, and methylcyclohexane; aromatic hydrocarbon-based solvents such as toluene, xylene, o-xylene, m-xylene, p-xylene, and cresol; and ketone-based solvents such as acetone, 2-butanone, 2-pentanone, 3-pentanone, cyclopentanone, cyclohexanone, and methyl isobutyl ketone. Alternatively, a mixture of two or more solvents in any combination may be used.

[0094] In the polycarbonate manufacturing method of this embodiment, the reaction temperature in the polymerization step is not particularly limited as long as it is within the range that allows for the production of the polycarbonate of this embodiment, but is preferably 0°C to 150°C, more preferably 0°C to 60°C, and even more preferably 0°C to 40°C. By having the reaction temperature in the polymerization step within the above range, it becomes even easier to control the weight-average molecular weight of the obtained polycarbonate to the range of 50,000 to 500,000. In the polycarbonate manufacturing method of this embodiment, the polymerization time is preferably 2 to 360 hours, more preferably 4 to 240 hours, and even more preferably 8 to 150 hours. Furthermore, in the polycarbonate manufacturing method of this embodiment, polymerization is preferably carried out under an inert gas atmosphere (for example, Ar or N2).

[0095] In the polycarbonate production method of this embodiment, in order to control the average molecular weight of the obtained polycarbonate resin, a solvent in which the polymer is insoluble may be added to precipitate the polymer when a predetermined molecular weight is reached, or the reaction solution may be brought into contact with air to deactivate the catalyst, or a polymerization inhibitor may be added. The solvent used to precipitate the polymer is not particularly limited, but examples include methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, decanol, etc. The method of contacting with air is not particularly limited, but for example, the reaction solution may be directly exposed to air, or a solvent that has not been purged with an inert gas may be added to the reaction solution. Polymerization inhibitors are not particularly limited, but examples include inorganic and organic acids such as hydrochloric acid, sulfuric acid, nitric acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid, phosphoric acid, metaphosphoric acid, formic acid, acetic acid, propionic acid, butyric acid, lactic acid, citric acid, ascorbic acid, gluconic acid, oxalic acid, tartaric acid, meldrumic acid, and benzoic acid.

[0096] In the method for producing polycarbonate according to this embodiment, it is preferable to have a purification step. The purification method is not limited to the following, but examples include devolving purification by heating under reduced pressure, precipitation purification using a precipitation solvent, and purification using a metal scavenger. Furthermore, one type of purification step may be used alone, or two types may be used in combination.

[0097] [Devolatilization purification] In the purification process of the polycarbonate used in this embodiment, devolatilization purification may or may not be used. The devolatilization purification conditions are not particularly limited as long as they are within the range that can purify the polycarbonate of this embodiment, but the devolatilization temperature is preferably 0 to 300°C, more preferably 0 to 270°C, and even more preferably 100 to 270°C. The devolatilization pressure is preferably 0 to 80 kPaA, more preferably 0 to 50 kPaA, and even more preferably 0 to 10 kPaA.

[0098] [Precipitation and purification] In the polycarbonate purification process of this embodiment, precipitation purification may or may not be used. The precipitation purification conditions are not particularly limited as long as they are within a range that can purify the polycarbonate of this embodiment, but the precipitation solvent is preferably an alcohol solvent such as methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, or decanol.

[0099] [Purification using metal scavengers] In the purification process of the polycarbonate in this embodiment, purification using a metal scavenger may or may not be used. The purification conditions are not particularly limited as long as they are within a range that can purify the polycarbonate of this embodiment, but the metal scavenger used is preferably one in which a structure containing amino groups, thiol groups, hydroxyl groups, imidazole groups, phosphate groups, carbonyl groups, sulfone groups, etc., is supported on silica gel or the like.

[0100] The polycarbonate of this embodiment is not particularly limited in terms of stereoregularity, but examples include isotactic, syndiotactic, and atactic structures. In the polycarbonate of this embodiment, an atactic structure is preferred from the viewpoint of improving transparency, while an isotactic or syndiotactic structure is preferred from the viewpoint of improving chemical resistance and mechanical strength.

[0101] The polycarbonate of this embodiment may have two or more polymerization arrangements. To further enhance transparency, it is preferable to use a random copolymer or an alternating copolymer. To further enhance chemical resistance and mechanical strength, it is preferable to use a block copolymer. Generally, many aliphatic and alicyclic (especially 5-membered and 6-membered ring) polycarbonates, including polyethylene carbonate, tend to have low heat resistance. However, by including structural units represented by general formula (3) and / or formula (4) as copolymer components, it is possible to improve the heat resistance of the resulting copolymer. From the viewpoint of improving the heat resistance of the copolymer, it is preferable that the content of structural units represented by general formula (3) and / or formula (4) is 50 mol% or more. Seven-membered ring carbonates exhibit relatively high heat resistance, and copolymerizing them with structural units represented by general formula (3) and / or formula (4) tends to further improve heat resistance and is preferable because it allows for a higher glass transition temperature (Tg). [Examples]

[0102] The present invention will be described in more detail using examples and comparative examples, but the present invention is not limited in any way by these examples.

[0103] [Synthesis of pre-catalysts and monomers]

[0104] In the following examples, reagents used were those manufactured by Fujifilm Wako Pure Chemical Industries unless otherwise specified. Unless otherwise noted, all examples were carried out under a dry nitrogen atmosphere using a dry solvent.

[0105] In this embodiment, the pre-catalyst, carbonate monomer, structural analysis, and measurement of the physical properties of the polycarbonate were performed as follows.

[0106] (Identification of the structures of pre-catalysts, polymers, and monomers) The structure and purity of the compounds and pre-catalysts obtained in the examples were determined using nuclear magnetic resonance (NMR, JEOL ECZ400S: probe TFH) and single-crystal X-ray diffraction (Bruker D8 VENTURE, Cu source). The reference peak for the deuterated solvent used in NMR measurements was determined when chloroform-d (hereinafter referred to as CDCl3) was used. 1 HNMR: 7.26 ppm, 13 ¹1 1H NMR: 2.08 ppm, 13 13C NMR: 20.43 ppm. When benzene-d6 (hereinafter referred to as C6D6) is used, 1 1H NMR: 7.16 ppm, 13 13C NMR: 128.06 ppm. When tetrahydrofuran-d8 (hereinafter referred to as thf-d8) is used, 1 1H NMR: 1.72 ppm, 13 the measurement was carried out with 13C NMR at 67.21 ppm.

[0107] [Synthesis of Pre-catalyst A]

[0108] [Chemical Formula]

[0109] 5-tert-butyl-2-hydroxybenzaldehyde (1.00 g, 5.62 mmol, Sigma-Aldrich) was weighed into a 50 mL three-necked flask, and the interior of the flask was replaced with nitrogen. After adding 15 mL of dehydrated ethanol into the flask, the flask was immersed in an oil bath, the internal temperature was heated to 78° C. to achieve a reflux state, and the compound was completely dissolved by stirring with a magnetic stirrer. Subsequently, ethylenediamine (0.169 g, 2.81 mmol, Tokyo Chemical Industry) was added and stirred for 4 hours. The precipitated yellow solid was collected by vacuum filtration and washed with 20 mL of ethanol. The obtained yellow solid was vacuum-dried at 40° C. for 6 hours, to obtain 1.00 g of the target product (the compound represented by the above formula (15)). 1 1H NMR (CDCl3, 400MHz): δ 13.01 (s, 2H), 8.35 (s, 2H), 7.33 (dd, J = 8.8, 2.4 Hz, 2H), 7.20 (d, J = 2.4 Hz, 2H), 6.88 (d, J = 8.8 Hz, 2H), 3.93 (s, 4H), 1.28 (s, 18H), 13 C{ 1H} NMR(CDCl3, 100 MHz): δ166.98, 158.78, 141,47, 129.85, 128.06, 118.04, 116.56, 60.10, 34.09, 31.55

[0110] [ka] In a glove box, 0.687 g (1.81 mmol) of ligand A (the compound represented by formula (15) above) and 8.90 g of tetrahydrofuran (hereinafter also referred to as "THF") were added to a 30 mL Schlenk tube dried at 150°C, and the mixture was stirred at room temperature using a magnetic stirrer to completely dissolve the compound. Subsequently, 1.91 mL (3.62 mmol) of sodium bis(trimethylsilyl)amide / THF solution (1.9 M, Tokyo Chemical Industry Co., Ltd.) was added, the tube was tightly sealed with a glass stopper, and the mixture was stirred for 2 hours to obtain solution A. In parallel, 0.445 g (1.81 mmol, Thermo Scientific Chemicals) of CeCl3 and 21.4 g of THF were added to a 100 mL Schlenk tube dried at 150°C, the tube was tightly sealed with a glass stopper, and the mixture was stirred for 2 hours to obtain solution B. These Schlenk tubes were removed from the glove box. Solution A was stirred at room temperature for 30 minutes under a nitrogen atmosphere, and solution B was stirred in a low-temperature reactor at -78°C for 30 minutes. Then, solution A was pumped into solution B using dry nitrogen and the Schlenk tube technique, and stirred at -78°C for 2 hours. After evaporating the solvent in the Schlenk tubes using a vacuum line, the purified compound was exposed to air in a desiccator for 15 minutes. Subsequently, the Schlenk tubes were purged with dry nitrogen and placed in the glove box. Next, 50 mL of super-dehydrated toluene was added to the Schlenk tubes in the glove box to dissolve the compound, and toluene-insoluble components were removed by cotton filtration and suction filtration using a 1 μm PTFE filter. The solvent of the obtained toluene solution was evaporated to obtain 540 mg of the reddish-brown target cerium complex (formula (16): pre-catalyst A). 1H NMR(toluene-d8, 400MHz): δ 7.97(s,4H), 7.06(dd, J = 8.8, 2.8Hz, 4H), 6. 95(d, J = 2.8 Hz, 4H), 6.20(d, J=8.8 Hz, 4H), 4.16(s, 8H), 1.18(s, 36H), 13 C{ 1 H} NMR(C6D6, 100 MHz): δ 166.02, 164.55, 138.29, 131.20, 130.44, 123.09, 117.61, 63.74, 33.68, 31.73

[0111] Figure 1 shows the structure of pre-catalyst A determined by single-crystal X-ray analysis (ORTEP diagram). The single-crystal X-ray analysis was performed as follows: The reddish-brown crystals were transferred to a glass slide containing crystal fixing oil (Parabar 10312, HAMPTON RESEARCH). A single crystal was then selected and mounted on a goniometer head. Data was collected under the following conditions: X-ray source: Cu-Kα, measurement temperature: 100K, voltage / current: 50kV-1.2mA, exposure time: 10 seconds. Subsequently, the collected data was analyzed using SHELEX software to determine the structure. The crystals used for single-crystal X-ray structure analysis were obtained by recrystallization using heptane.

[0112] [Synthesis of pre-catalyst B]

[0113] [ka] 6,6'-((ethane-1,2-diylbis(azanylidene))bis(methanylylidene))bis(2,4-di-tert-butylphenol) (0.350 g, 0.710 mmol, BLD pharm) was dried in a vacuum oven at 60°C for 4 hours, and then added to a 30 mL Schlenk tube that had been dried at 150°C in a glove box. Subsequently, 3.50 g of THF was added, and the compound was stirred at room temperature using a magnetic stirrer to completely dissolve it. Then, sodium bis(trimethylsilyl)amide / THF solution (1.9 M, Tokyo Chemical Industry Co., Ltd.) (0.747 mL, 1.49 mmol) was added, the container was tightly sealed with a glass stopper, and stirred for 2 hours to obtain solution C. In parallel, 0.175 g of CeCl3 (7.11 mmol, Thermo Scientific Chemicals) and 8.30 g of THF were added to a 30 mL Schlenk tube dried at 150°C, and the tube was sealed with a glass stopper and stirred for 2 hours to obtain solution D. These Schlenk tubes were removed from the glove box, and solution C was stirred at room temperature for 30 minutes under a nitrogen atmosphere. Solution D was stirred in a low-temperature reactor at -78°C for 30 minutes. Then, solution A was pumped into solution B using dry nitrogen and the Schlenk tube technique, and stirred at -78°C for 2 hours. After evaporating the solvent in the Schlenk tube using a vacuum line, the purified compound was exposed to air in a desiccator for 15 minutes. Subsequently, the Schlenk tube was purged with dry nitrogen and placed in a glove box. Next, super-dehydrated toluene was added to a 50 mL Schlenk tube in the glove box to dissolve the compound, and toluene-insoluble components were removed by cotton filtration and suction filtration using a 1 μm PTFE filter. The solvent in the obtained toluene solution was evaporated to obtain 339 mg of the target purple cerium complex (formula (17): pre-catalyst B). 1 1H NMR (C6D6, 400MHz): δ 8.52(s, 4H), 7.52(d, J = 2.8 Hz, 4H), 7.10(d, J = 2.8 Hz, 4H), 4.60 Hz(s, 8H), 1.41(s, 36H), 1.28(s, 36H), 13 C{ 1H} NMR(C6D6, 100 MHz): δ168.04, 166.83, 138.21, 135.89, 130.10, 129.54, 124.59, 64.26, 35.31, 33.93, 31.78, 30.30

[0114] [Synthesis of carbonate monomers]

[0115] (Synthesis Example 1) Synthesis of 4-di-O-octyl-2,3:5,6-dicarbonate-myo-inositol (hereinafter also referred to as "OCI")

[0116] (Step 1-1) Synthesis of 2,3:5,6-di-O-cyclohexylidene-myo-inositol [ka] In a 500 mL four-necked flask that had been degassed and purged with argon (Ar), myo-inositol (125 g, 0.69 mol) was dispersed in anhydrous dimethylformamide (hereinafter also referred to as "DMF"; 860 mL). 1,1-dimethoxycyclohexane (400 g, 2.77 mol) and p-toluenesulfonic acid monohydrate (13.2 g, 69 mmol, Kishida Chemical) were added in sequence, and the resulting reaction mixture was heated to 100 °C. After 45 minutes, trimethylamine (30 mL) was added to the reaction mixture, and the reaction mixture was concentrated under reduced pressure. The resulting concentrate was dissolved in ethyl acetate (3.0 L) and washed with 5% by mass aqueous sodium bicarbonate solution (400 mL). The ethyl acetate phase was dried over an appropriate amount of sodium sulfate, filtered, and then concentrated under reduced pressure to obtain a solid. The concentrated solid obtained was recrystallized with diisopropyl ether (1.0 L) to yield 50.5 g of colorless crystals of 2,3:5,6-di-O-cyclohexylidene-myo-inositol (formula (20) above).

[0117] (Steps 1-2) Synthesis of 1,4-di-O-octyl-2,3:5,6-di-O-cyclohexylidene-myo-inositol derivative (hereinafter also referred to as "OCyI") [ka] 55% sodium hydride (8.66 g, 198 mmol, Kanto Chemical) was added to a 200 mL two-necked flask and washed with hexane. After degassing and purging the flask with N2, a solution of the diol compound (2,3:5,6-di-O-cyclohexylidene-myo-inositol) (15.0 g, 44.1 mmol) obtained in step 1-1 was dissolved in dimethylformamide (DMF, 171 mL, Kanto Chemical) and added to the flask. The solution in the flask was stirred at room temperature for 1 hour, and then reacted with octyl bromide (17.4 g, 15.9 mmol, Tokyo Chemical Industry Co., Ltd.) under an ice bath. After stirring the reaction mixture at room temperature for 18 hours, 200 mL of water was added to obtain a precipitate. The precipitated 1,4-di-O-benzyl-2,3:5,6-di-O-cyclohexylidene-myo-inositol derivative was filtered off and washed with water. The filtrate was vacuum-dried to obtain 23.7 g of the colorless liquid 1,4-di-O-octyl-2,3:5,6-di-O-cyclohexylidene-myo-inositol derivative (formula (21) above).

[0118] (Steps 1-3) Synthesis of 1,4-di-O-octyl-myo-inositol (hereinafter also referred to as "OI")

[0119] [ka] Methanol (180 mL, Daishin Chemical) was added to a 500 mL round-bottom flask, and the OCyI (1,4-di-O-octyl-2,3:5,6-di-O-cyclohexylidene-myo-inositol derivative; 10.0 g, 17.7 mmol) obtained in the above (steps 1-2) was added and stirred to obtain a solution. To the obtained solution, concentrated hydrochloric acid (18 mL) was gradually added and the mixture was stirred at room temperature for 17 hours. The disappearance of the starting material was confirmed by thin-layer chromatography (TLC). The resulting reaction mixture was concentrated under reduced pressure, and the remaining material was recrystallized in a mixed solvent of ethyl acetate and hexane to obtain 5.01 g of 1,4-di-O-octyl-myo-inositol (formula (22) above) as white crystals.

[0120] (Steps 1-4) Synthesis of 1,4-di-O-octyl-2,3:5,6-dicarbonate-myo-inositol (hereinafter also referred to as "OCI") [ka] In a 1 L round-bottom flask, 1,4-di-O-octyl-myo-inositol (4.50 g, 11.1 mmol), triethylamine (31.2 mL, 223 mmol, Kanto Chemical), and anhydrous THF (45.0 mL, Kanto Chemical) obtained in steps 1-3 above were added, and the resulting solution was cooled in an ice bath. To the cooled solution, ethyl chloroformate (61.2 mL, 642 mmol, Kishida Chemical) diluted with THF (63.0 mL) was added dropwise, and the reaction was carried out by stirring at room temperature for 30 minutes. Then, ethyl chloroformate (30.6 mL, 321 mmol) was added again to the reaction mixture, and the reaction was carried out by stirring for 1 hour. The salt formed in the reaction mixture was removed by filtration. The resulting filtrate was neutralized with 1% hydrochloric acid by mass until it became acidic, and then the THF was removed by distillation. The resulting residue was dissolved in ethyl acetate (600 mL) and washed with water. The organic phase was dried over anhydrous magnesium sulfate and then concentrated under reduced pressure. The resulting concentrate was recrystallized from hexane to obtain 2.25 g of 1,4-di-O-octyl-2,3:5,6-dicarbonate-myo-inositol (OCI: a cyclic carbonate represented by formula (23) above) as white crystals. 1 H NMR(CDCl3, 400MHz): δ 5.04-5.06(1H, m), 4.63-4.66(1H, m), 4.40-4.46(1H, m), 3,61-3.99(7H, m), 0.82-1,67(m, 30H)

[0121] (Synthesis Example 2) Synthesis of trans-cyclohexene carbonate (hereinafter also referred to as "T6C") [ka] Under an argon stream, trans-1,2-cyclohexanediol (200.0 g, 1.722 mmol) and anhydrous 1,4-dioxane (2.0 L) were added to a 5 L four-necked flask. Then, while stirring with a mechanical stirrer and cooling the reaction vessel in an ice bath, ethyl chloroformate (280.2 g, 2.582 mmol) was slowly added dropwise to the reaction mixture. Furthermore, while maintaining stirring and cooling, a solution of triethylamine (348.4 g, 3.443 mmol) diluted with anhydrous toluene (2.5 L) was slowly added dropwise to the reaction mixture. After the addition, the mixture was stirred for 1.5 hours while maintaining cooling, then the internal temperature of the reaction vessel was raised to room temperature, and the mixture was stirred for a further 12 hours. The resulting white solid was removed by vacuum filtration, and the filtrate was concentrated under reduced pressure. Ethyl acetate (2.0 L) was added to the residue to dissolve it, and then the mixture was washed with 1% hydrochloric acid aqueous solution (2.0 L). The organic layer was collected and washed three times with deionized water (2.0 L). Further dehydration was performed by adding magnesium sulfate, followed by vacuum filtration. The filtrate was concentrated under reduced pressure to obtain a white solid, which was purified by silica gel column chromatography to obtain 110.0 g of the target trans-cyclohexene carbonate (T6C: a cyclic carbonate represented by formula (24) above). 1 H NMR(CDCl3, 400MHz): δ3.98-4.05(m, 2H), 2.24-2.28(m, 2H), 1.86-1.98(m, 2H),1.60- 1.75(m, 2H), 1.37-1.47(m, 2H), 13 C{ 1 H} NMR(CDCl3, 100 MHz): δ155.06, 83.47, 28.08, 23.01

[0122] [Polycarbonate derived from myo-inositol] In this embodiment, the physical properties of the polycarbonate were measured as follows.

[0123] (Measurement of molecular weight in terms of polystyrene) A solution prepared by adding 2.0 g of tetrahydrofuran to 0.02 g of polycarbonate was used as the measurement sample, and the weight-average molecular weight of the polycarbonate was measured using a high-speed GPC instrument (Tosoh Corporation, product name "HLC-8420GPC"). The columns used were Tosoh Corporation's TSK Guard Column SuperH-H, TSKgel SuperHM-H, TSKgel SuperHM-H, TSKgel SuperH2000, and TSKgel SuperH1000 (all Tosoh Corporation product names) connected in series. The column temperature was 40°C, and analysis was performed at a rate of 0.60 mL / min using tetrahydrofuran as the mobile phase. An RI detector was used as the detector. Calibration curves were created using polystyrene standard samples from Polymer Standards Service (molecular weights: 2,520,000, 1,240,000, 552,000, 277,000, 130,000, 66,000, 34,800, 19,700, 8,680, 3470, 1306, 370) as standard samples. Based on these calibration curves, the number-average molecular weight Mn and weight-average molecular weight Mw of polycarbonate were determined.

[0124] (Thermogravimetric measurement) Using a Shimadzu TG-DTA apparatus (product name: DTG-60A) and an aluminum krypton cell, polycarbonate was heated to 400°C at a rate of 10°C / min in a nitrogen stream. The thermal decomposition (TGA) of the polycarbonate composition was measured, and the temperature at which the weight of the TGA curve decreased by 10% was defined as the 10% weight loss temperature (°C).

[0125] (Example B-1) In a glove box, OCI (4.00 g, 8.77 mmol, cyclic carbonate obtained in Synthesis Example 1), which had been dried under reduced pressure at 150°C in a vacuum oven for 2 hours at 60°C, was placed in a 30 mL screw bottle. Then, 6.00 g of super-dehydrated toluene was added, and the mixture was stirred with a magnetic stirrer and a rotor to obtain a homogeneous solution. Next, pre-catalyst A (11.2 mg, 0.00877 mmol) was added, and the mixture was stirred again to obtain a homogeneous solution. Then, one-electron reducing agent CoCp2 (1.66 mg, 0.0125 mmol, Ardrich) was added, and the ring-opening polymerization reaction was carried out by stirring at room temperature for 4 days. 10.0 g of super-dehydrated acetone was added to the reaction solution, and the reaction solution was removed from the glove box. The reaction solution was added to 150 mL of methanol to precipitate the polymer. The precipitated polymer was recovered by vacuum filtration and washed with methanol. The obtained polymer was vacuum-dried at 100°C for 1 hour to obtain 2.21 g of polymer. 4.00 g of acetone and 4.00 g of stabilizer-free THF were added to this polymer and stirred to form a homogeneous solution. Then, metal scavenger (R-Cat-Sil, MP, Kanto Chemical) was added until the solution became clear, and the mixture was left to stand for about 30 minutes. Afterward, the metal scavenger was removed by pressure filtration using a 1 μm pore size membrane filter (PTFE type), and the solution was collected. The metal scavenger was washed with 10 mL of acetone. The collected solution and the washing solution were mixed and added to 150 mL of methanol to re-precipitation the polymer. The precipitated polymer was collected by vacuum filtration and washed with methanol. The resulting polymer was vacuum-dried at 100°C for 4 hours to obtain 1.51 g of polymer (polycarbonate). 50 mg of the obtained polycarbonate was dissolved in 1 mL of various solvents (acetone, THF, chloroform, toluene, DMF, 1,4-dioxane), showing high solubility. Furthermore, the obtained homopolymer 1 The HNMR measurement results are shown in Figure 2. The sample dissolved in CDCl3 1In the 1H-NMR spectrum, signals at 2.3–5.7 ppm were observed at concentrations attributed to the 10H fraction consisting of 6H hydrogen atoms bonded to the cyclohexene ring of OCI and 4H methylene hydrogen atoms adjacent to the oxygen atom of the octoxy group, while signals at 0.3–2.0 ppm were observed at concentrations attributed to the 30H fraction of hydrogen atoms excluding the 4H methylene hydrogen atoms adjacent to the oxygen atom of the octoxy group. Furthermore, the polystyrene-equivalent molecular weight (number-average molecular weight (Mn), weight-average molecular weight (Mw)) and the 10% weight loss temperature (°C) of the obtained polymer were determined. The results are shown in Table 1.

[0126] (Example B-2) The ring-opening polymerization reaction was carried out in the same manner as in Example B-1, except that the one-electron reducing agent was changed to bis(pentamethylcyclopentadienyl)cobalt(II) (hereinafter also referred to as "CoCp*2", 4.11 mg, 0.0125 mmol, Ardrich), yielding 1.88 g of OCI polymer (polycarbonate). The polystyrene-equivalent molecular weight (number average molecular weight (Mn), weight average molecular weight (Mw)) and the 10% weight loss temperature (°C) of the obtained polymer (polycarbonate) were determined. The results are shown in Table 1.

[0127] (Comparative example B-1) In a 30 mL Schlenk tube dried under reduced pressure at 150°C, T6C (1.01 g, 7.04 mmol), dried in a vacuum oven at 40°C for 2 hours, was added, and the flask was purged with nitrogen. Super-dehydrated toluene (4.02 g) was added to the flask, and the mixture was stirred using a magnetic stirrer and rotor to completely dissolve the monomer and obtain a monomer solution. Separately, in a 30 mL Schlenk tube dried under reduced pressure at 150°C, benzyl alcohol (0.0381 g, 0.352 mmol, hereafter also referred to as "BnOH") and 1.00 mL of super-dehydrated toluene were added, and the mixture was purged with nitrogen. Then, a tetrahydrofuran solution of potassium tert-butoxide (1.0 M, 0.0352 mL, 0.0352 mmol, hereafter also referred to as "tBuOK") was added to prepare an initiator solution. While stirring the T6C toluene solution, 0.536 mL of the prepared initiator solution was added, and the mixture was stirred at room temperature for 30 minutes. 0.0011 g of acetic acid was added to stop the reaction and obtain a polymerization solution containing polycarbonate. 2.0 g of super-dehydrated acetone was added to this solution and immersed in 80 mL of methanol to precipitate the polymer. The precipitated polymer was recovered by vacuum filtration and washed with methanol. The obtained polymer was vacuum-dried at 100°C for 1 hour to obtain 0.912 g of polymer. The polystyrene-equivalent molecular weight (number average molecular weight (Mn), weight average molecular weight (Mw)) and the 10% weight loss temperature (°C) of the obtained polymer were determined. The results are shown in Table 1.

[0128] (Comparative example B-2) In a 100 mL Schlenk tube dried under reduced pressure at 150°C, 5.00 g (35.2 mmol) of T6C, dried in a vacuum oven at 40°C for 2 hours, was added, and the flask was purged with nitrogen. 15.3 g of super-dehydrated toluene was added to the flask, and the mixture was stirred using a magnetic stirrer and rotor to completely dissolve the monomer and obtain a monomer solution. Separately, in a 30 mL Schlenk tube dried under reduced pressure at 150°C, 0.0218 g (0.201 mmol) of benzyl alcohol and 1.00 mL of super-dehydrated toluene were added, and the mixture was purged with nitrogen. Then, a tetrahydrofuran solution of potassium tert-butoxide (1.0 M, 0.100 mL, 0.100 mmol) was added to prepare an initiator solution. While stirring the T6C toluene solution, 0.282 mL of the prepared initiator solution was added, and the mixture was stirred at room temperature for 30 minutes. 0.0021 g of acetic acid was added to stop the reaction and obtain a polymerization solution containing polycarbonate resin. 10.0 g of super-dehydrated acetone was added to the solution and immersed in 400 mL of methanol to precipitate the polymer. The precipitated polymer was recovered by vacuum filtration and washed with methanol. The obtained polymer was vacuum-dried at 100°C for 1 hour to obtain 4.52 g of polymer. The polystyrene-equivalent molecular weight (number-average molecular weight (Mn), weight-average molecular weight (Mw)) and the 10% weight loss temperature (°C) of the obtained polymer were determined. The results are shown in Table 1.

[0129] (Comparative example B-3) In a 30 mL Schlenk tube dried under reduced pressure at 150°C, OCI (3.21 g, 7.04 mmol), dried in a vacuum oven at 40°C for 2 hours, was added, and the flask was purged with nitrogen. Super-dehydrated toluene (12.84 g) was added to the flask, and the mixture was stirred using a magnetic stirrer and rotor to completely dissolve the monomer and obtain a monomer solution. Separately, in a 30 mL Schlenk tube dried under reduced pressure at 150°C, benzyl alcohol (0.0109 g, 0.101 mmol) and 1.00 mL of super-dehydrated toluene were added, and the mixture was purged with nitrogen. Then, a solution of potassium tert-butoxide in tetrahydrofuran (1.0 M, 0.101 mL, 0.101 mmol) was added to prepare an initiator solution. While stirring the OCI toluene solution, 0.111 mL of the prepared initiator solution was added, and the mixture was stirred at room temperature for 30 minutes. The reaction was stopped by adding 0.0011 g of acetic acid, then 8.0 g of super-dehydrated acetone was added to the solution and placed in 120 mL of methanol to precipitate the polymer. The solution was then filtered under reduced pressure, but no polymer was obtained.

[0130] [Table 1]

[0131] Table 1 shows that the polycarbonates of Examples B-1 and B-2 have a 10% higher temperature of weight loss compared to the polycarbonates of Comparative Examples B-1 and B-2, indicating sufficient heat resistance.

[0132] [Heat-resistant poly(cyclohexene carbonate)]

[0133] In this embodiment, the physical properties of the polycarbonate were measured as follows.

[0134] (Measurement of molecular weight in terms of polystyrene) A solution prepared by adding 2.0 g of tetrahydrofuran to 0.02 g of polycarbonate was used as the measurement sample, and the weight-average molecular weight of the polycarbonate was measured using a high-speed GPC instrument (Tosoh Corporation, product name "HLC-8420GPC"). The columns used were Tosoh Corporation's TSK Guard Column SuperH-H, TSKgel SuperHM-H, TSKgel SuperHM-H, TSKgel SuperH2000, and TSKgel SuperH1000 (all Tosoh Corporation product names) connected in series. The column temperature was 40°C, and analysis was performed at a rate of 0.60 mL / min using tetrahydrofuran as the mobile phase. An RI detector was used as the detector. Calibration curves were created using polystyrene standard samples from Polymer Standards Service (molecular weights: 2,520,000, 1,240,000, 552,000, 277,000, 130,000, 66,000, 34,800, 19,700, 8,680, 3470, 1306, 370) as standard samples. Based on these calibration curves, the number-average molecular weight Mn and weight-average molecular weight Mw of polycarbonate were determined.

[0135] (Measurement of absolute molecular weight and intrinsic viscosity) A) Measuring equipment Measurements were performed using the following measuring equipment and conditions. Equipment: Size removal chromatography (Tosoh HLC-8320GPC (with TSKgel GMHXL and TSKgel G1000HXL columns)), M alvern OMNISEC REVEAL (RI (Refractive Index) detector, viscometer, light scattermeter (LALS7° (Low Angle Light Scattering detector), RA LS90° (Right Angle Light Scattering detector), 640nm laser)) Column temperature: 40℃ Eluent:THF Flow rate: 1mL / min Injection volume: 100μL B) Sample measurement B-1) RI detector calibration Standard polystyrene F-10 (product name manufactured by Tosoh Corporation, Mw=9.64×10) in 1.00 mg / mL THF 4 The RI detector was calibrated using GPC measurement results for Mw / Mn = 1.01 (LS (Light Scattering) calculation) and dn / dc (Refractive Index Increment) = 0.185. Subsequently, standard polystyrene F-40 (Tosoh Corporation product name, LS calculation Mw = 4.27 × 10) was used. 5 We measured Mw / Mn=1.02 and confirmed that the measurement results were consistent. B-2) Sample Preparation THF was added to the sample concentration to 2.00 mg / mL and allowed to stand overnight. The mixture was then filtered through a 0.45 μm disc filter. B-3) Measurement / analysis The samples prepared in B-2 were subjected to measurement according to the apparatus and conditions described above. The absolute molecular weight was determined from the RALS, LALS, and dn / dc values, and the absolute molecular weight between 50,000 and 650,000 was plotted on the x-axis, with the corresponding intrinsic viscosity (η) on the y-axis. Subsequently, the average intrinsic viscosity (η(average)) for absolute molecular weights in the range of 50,000 to 650,000 was calculated according to the following formula (2). Note that dn / dc was calculated from the area value of the RI detector. η(average) = (sum of intrinsic viscosities for each absolute molecular weight) / (number of plots in the range of absolute molecular weights from 50,000 to 650,000) ... (2)

[0136] (Thermogravimetric measurement) Using a Shimadzu TG-DTA apparatus (product name: DTG-60A) and an aluminum krypton cell, polycarbonate was heated to 400°C at a rate of 10°C / min in a nitrogen stream. The thermal decomposition (TGA) of the polycarbonate resin composition was measured, and the temperature at which the weight of the TGA curve decreased by 10% was defined as the 10% weight loss temperature (°C).

[0137] (Example C-1) In a glove box, T6C (1.50 g, 10.6 mmol, cyclic carbonate obtained in Synthesis Example 2), which had been dried under reduced pressure at 150°C in a vacuum oven for 2 hours, was placed in a 30 mL screw bottle. Then, 2.25 g of super-dehydrated toluene was added, and the mixture was stirred with a magnetic stirrer and a rotor to obtain a homogeneous solution. Subsequently, pre-catalyst A (13.6 mg, 0.0151 mmol) was added, and the mixture was stirred again to obtain a homogeneous solution. Then, the one-electron reducing agent bis(cyclopentadienyl)cobalt(II) (hereinafter, CoCp2) (2.86 mg, 0.0151 mmol, Ardrich) was added, and the ring-opening polymerization reaction was carried out by stirring at room temperature for 4 days. 10.0 g of super-dehydrated acetone was added to the reaction solution, and the reaction solution was removed from the glove box. The reaction solution was added to 150 mL of methanol to precipitate the polymer. The precipitated polymer was recovered by vacuum filtration and washed with methanol. The obtained polymer was vacuum-dried at 100°C for 1 hour to obtain 1.21 g of polymer. 3.50 g of acetone and 3.50 g of stabilizer-free THF were added to this polymer and stirred to form a homogeneous solution. Then, a metal scavenger (R-Cat-Sil, MP, Kanto Chemical) was added until the solution became clear, and the mixture was left to stand for about 30 minutes. After that, the metal scavenger was removed by pressure filtration using a 1 μm pore size membrane filter (PTFE type), and the solution was collected. The metal scavenger was washed with 10 mL of acetone. The collected solution and the washing solution were mixed and added to 150 mL of methanol to precipitate the polymer again. The precipitated polymer was collected by vacuum filtration, washed with methanol, and the resulting polymer was vacuum-dried at 100°C for 4 hours to obtain 0.856 g of polymer (polycarbonate). The polystyrene-equivalent molecular weight (number-average molecular weight (Mn), weight-average molecular weight (Mw)), average intrinsic viscosity (η (average)), and 10% weight loss temperature (°C) of the obtained polymer (polycarbonate) were determined. The results are shown in Table 2.

[0138] (Example C-2) In a glove box, T6C (1.00 g, 7.07 mmol, cyclic carbonate obtained in Synthesis Example 2), which had been dried under reduced pressure at 150°C in a vacuum oven for 2 hours, was placed in a 30 mL screw bottle. Then, 1.50 g of super-dehydrated toluene was added, and the mixture was stirred with a magnetic stirrer and a rotor to obtain a homogeneous solution. Next, pre-catalyst A (9.01 mg, 0.0101 mmol) was added, and the mixture was stirred again to obtain a homogeneous solution. Then, the one-electron reducing agent bis(cyclopentadienyl)cobalt(II) (hereinafter, CoCp2) (1.91 mg, 0.0101 mmol, Ardrich) was added, and the ring-opening polymerization reaction was carried out by stirring at room temperature for 4 days. 7.2 g of super-dehydrated acetone was added to the reaction solution, and the reaction solution was removed from the glove box. The reaction solution was added to 100 mL of methanol to precipitate the polymer. The precipitated polymer was recovered by vacuum filtration and washed with methanol. The obtained polymer was vacuum-dried at 100°C for 4 hours to obtain 1.26 g of polymer. The polystyrene-equivalent molecular weight (number-average molecular weight (Mn), weight-average molecular weight (Mw)), average intrinsic viscosity (η (average)), and 10% weight loss temperature (°C) of the obtained polymer were determined. The results are shown in Table 2.

[0139] (Example C-3) In a glove box, a 30 mL vacuum sample tube (manufactured by Furukawa Rikou) dried under reduced pressure at 150°C was filled with T6C (1.50 g, 10.6 mmol, cyclic carbonate obtained in Synthesis Example 2) that had been dried under reduced pressure in a vacuum oven at 40°C for 2 hours. Then, 2.25 g of super-dehydrated toluene was added, and the mixture was stirred with a magnetic stirrer and a rotor to obtain a homogeneous solution. Subsequently, pre-catalyst B (16.9 mg, 0.0151 mmol) was added, and the mixture was stirred again to obtain a homogeneous solution. After that, the one-electron reducing agent bis(cyclopentadienyl)cobalt(II) (hereinafter, CoCp2) (2.86 mg, 0.0151 mmol, Ardrich) was added, the container was sealed with a Teflon needle valve, and the ring-opening polymerization reaction was carried out by stirring for a total of 87 hours in a 40°C oil bath, while taking a sample of the solution and checking the molecular weight. For molecular weight confirmation, the tube was opened with a nitrogen flow condition and the needle valve was opened to obtain the sample solution. The needle valve was then sealed while maintaining the nitrogen flow, preserving the inert gas state inside the tube. After confirming that the desired molecular weight had been reached, the reaction solution was removed from the oil bath and 10.0 g of super-dehydrated acetone was added. The reaction solution was added to 150 mL of methanol to precipitate the polymer. The precipitated polymer was recovered by vacuum filtration and washed with methanol. The obtained polymer was vacuum-dried at 100°C for 1 hour to obtain 0.94 g of polymer. 3.00 g of acetone and 3.00 g of stabilizer-free THF were added to this polymer and stirred to form a homogeneous solution. Metal scavenger (R-Cat-Sil, MP, Kanto Chemical) was then added until the solution became clear, and it was left to stand for about 30 minutes. Afterward, the metal scavenger was removed by pressure filtration using a 1 μm pore size membrane filter (PTFE type), and the solution was collected. The metal scavenger was then washed with 10 mL of acetone. The recovered solution and washing solution were mixed and added to 150 mL of methanol to re-precipitation the polymer. The precipitated polymer was recovered by vacuum filtration, washed with methanol, and the resulting polymer was vacuum-dried at 100°C for 4 hours to obtain 0.856 g of polymer (polycarbonate).The polystyrene-equivalent molecular weight (number-average molecular weight (Mn), weight-average molecular weight (Mw)), average intrinsic viscosity (η (average)), and 10% weight loss temperature (°C) of the obtained polymer (polycarbonate) were determined. The results are shown in Table 2.

[0140] (Comparative example C-1) In a 50 mL three-necked flask dried under reduced pressure at 150 °C, 9.84 g of T6C (69.2 mmol), dried in a vacuum oven at 40 °C for 2 hours, was added, and the flask was purged with nitrogen. 39.5 g of super-dehydrated toluene was added to the flask, and the mixture was stirred using a magnetic stirrer and a rotor to completely dissolve the monomer and obtain a monomer solution. Separately, in a 30 mL Schlenk tube dried under reduced pressure at 150 °C, benzyl alcohol (0.0712 g, 0.658 mmol) and 2.90 mL of super-dehydrated toluene were added, and the mixture was purged with nitrogen. Then, a tetrahydrofuran solution of potassium tert-butoxide (1.0 M, 0.329 mL, 0.329 mmol) was added to prepare an initiator solution. While stirring the T6C toluene solution, 0.261 mL of the prepared initiator solution was added, and the mixture was stirred at room temperature for 30 minutes. 0.0015 g of acetic acid was added to stop the reaction and obtain a polymerization solution containing polycarbonate resin. Next, to evaluate the methanol-insoluble content, a reprecipitation procedure was performed as follows: A 2.0 mL sample of the polymerization solution was taken and diluted with 8.12 g of super-dehydrated toluene. The diluted solution was added to 100 mL of methanol to precipitate the polymer. The precipitated polymer was recovered by vacuum filtration, and the obtained polymer was vacuum-dried at 100°C for 4 hours to obtain a polymer (polycarbonate resin). The weight loss rate was determined from the thermogravimetric results when the obtained homopolymer was heated under a nitrogen atmosphere. The polystyrene-equivalent molecular weight (number average molecular weight (Mn), weight average molecular weight (Mw)), average intrinsic viscosity (η (average)), and 10% weight loss temperature (°C) of the obtained polymer were determined. The results are shown in Table 2.

[0141] (Comparative example C-2) As Comparative Example C-2, poly(cyclohexene carbonate) synthesized by copolymerization of cyclohexene oxide and carbon dioxide (Empower Materials, product name "QPAC130") was used. The polystyrene-equivalent molecular weight (number average molecular weight (Mn), weight average molecular weight (Mw)), average intrinsic viscosity (η (average)), and 10% weight loss temperature (°C) of this polymer were determined. The results are shown in Table 2.

[0142] [Table 2]

[0143] Table 2 shows that the polycarbonates of Examples C-1 to C-3 had a 10% weight loss temperature higher and improved heat resistance compared to the polycarbonates of Comparative Examples C-1 and C-2. [Industrial applicability]

[0144] According to the present invention, it is possible to provide a catalyst composition that yields polycarbonate with excellent catalytic activity and is more useful, as well as a method for producing polycarbonate. Furthermore, the polycarbonate of the present invention has industrial applicability in fields such as medical materials, engineering plastics, and optical materials.

Claims

1. A catalyst composition comprising a cerium complex represented by the following general formula (1) or (2) and a one-electron reducing agent. 【Chemistry 1】 【Chemistry 2】 (In formulas (1) and (2), R 1 , R 2 , R 1 ', R 2 ', X 1 , X 2 , X 3 , X 4 , X 5 , X 6 , X 7 , X 8 , Y 1 and Y 2 each independently represent a hydrogen atom, a linear, branched or cyclic saturated or unsaturated alkyl group having 1 to 10 carbon atoms, a linear, branched or cyclic saturated or unsaturated alkoxy group having 1 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, a halogen atom, a hydroxy group, an aldehyde group, a carboxyl group, an amino group, a thiol group, a nitro group, a cyano group, or an amide structure, carbonyl structure, ether structure, ester structure, phosphine structure, silyl structure or sulfonyl structure having a linear, branched or cyclic saturated or unsaturated alkyl group having 1 to 10 carbon atoms, and n is an integer of 0, 1 or 2.)

2. In formula (1) or (2) above X 2 , X 6 These are independently a t-butyl group or an isopropyl group. X 4 , X 8 These are independently a hydrogen atom, a methyl group, an isopropyl group, or a t-butyl group. Y 1 , Y 2 These are each hydrogen atoms, R 1 , R 2 , R 1 ', R 2 ', X 2 , X 3 , X 6 and X 7 These are independently selected from the group consisting of a hydrogen atom, a linear, branched, or cyclic saturated or unsaturated C1-C10 alkyl group, a linear, branched, or cyclic saturated or unsaturated C1-C10 alkoxy group, a C6-C40 aryl group, a halogen atom, a hydroxyl group, an aldehyde group, a carboxyl group, an amino group, a thiol group, a nitro group, a cyano group, or an amide structure, carbonyl structure, ether structure, ester structure, phosphine structure, silyl structure, or sulfonyl structure having a linear, branched, or cyclic saturated or unsaturated C1-C10 alkyl group. The catalyst composition according to claim 1, wherein the one-electron reducing agent is any of bis(cyclopentadienyl)cobalt(II), bis(pentamethylcyclopentadienyl)cobalt(II), samarium(II)iodide, sodium naphthalenide, metallic sodium, or metallic lithium.

3. In formula (1) or (2) above X 2 , X 6 These are each t-butyl groups, X 4 , X 8 These are independently a hydrogen atom, a methyl group, or a t-butyl group. Y 1 , Y 2 These are each hydrogen atoms, R 1 , R 2 , R 1 ', R 2 ', X 2 , X 3 , X 6 and X 7 The catalyst composition according to claim 1, wherein each of the elements is independently selected from the group consisting of a hydrogen atom and a linear, branched, or cyclic saturated or unsaturated alkyl group having 1 to 10 carbon atoms, and the one-electron reducing agent is any of bis(cyclopentadienyl)cobalt(II), bis(pentamethylcyclopentadienyl)cobalt(II), or samarium(II)iodide.

4. In formula (1) or (2) above X 2 , X 6 Each of these is a t-butyl group, X 4 , X 8 These are independently a hydrogen atom, a methyl group, or a t-butyl group. R 1 , R 2 , R 1 ', R 2 ', X 2 , X 3 , X 6 , X 7 , Y 1 and Y 2 That is a hydrogen atom, The catalyst composition according to claim 1, wherein the one-electron reducing agent is either bis(cyclopentadienyl)cobalt(II) or bis(pentamethylcyclopentadienyl)cobalt(II).

5. A polycarbonate containing 50 mol% to 100 mol% of the structural unit represented by the following general formula (3), and having a weight-average molecular weight Mw of 30,000 to 500,000. 【Transformation 3】 (In formula (3), R 3 and R 4 Each is independently a hydrogen atom, an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, an aromatic alkyl group having 7 to 30 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an acyl group having 1 to 11 carbon atoms, or an aryl group having 6 to 30 carbon atoms, R 3 and R 4 At least one of them is an alkyl group having 8 or more carbon atoms, OR 3 and OR 4 The units may be bonded to each other via alkylene groups or carbonyl groups to form a cyclic structure, and the alkylene groups may be substituted with hydroxyl groups, phosphate groups, amino groups, alkoxy groups, or ester groups, and carbonyl groups may be inserted into the main chain, where n is the number of repeating units.

6. The polycarbonate according to claim 5, comprising 80 mol% to 100 mol% of the structural unit represented by formula (3) and having a weight-average molecular weight Mw of 50,000 to 500,000.

7. The polycarbonate according to claim 5, comprising 100 mol% of the structural unit represented by formula (3) and having a weight-average molecular weight Mw of 70,000 or more and 500,000 or less.

8. A polycarbonate having a weight-average molecular weight Mw of 50,000 or more and 500,000 or less, an absolute molecular weight of 50,000 or more and 650,000 or less as measured by size-removal chromatography, low-angle light scattering detector (LALS), and right-angle light scattering detector (RALS), with an average intrinsic viscosity (η) of 0.5 or more and 4.0 or less, and containing a repeating structure represented by the following formula (4). 【Chemistry 4】 (In equation (4), n is the number of repeating units.)

9. The polycarbonate according to claim 8, wherein the weight-average molecular weight Mw is 50,000 or more and 500,000 or less, and the average intrinsic viscosity (η) of the absolute molecular weight is 50,000 or more and 650,000 or less is 1.0 or more and 3.5 or less.

10. A method for producing polycarbonate, comprising the step of ring-opening polymerization of a cyclic carbonate using a catalyst composition according to any one of claims 1 to 4.

11. The manufacturing method according to claim 10, wherein the structure of the cyclic carbonate is represented by the following general formula (5) or (6), and the catalyst composition according to any one of claims 1 to 4 is used in an amount of 1 / 100th of a mole percent or less relative to the cyclic carbonate. 【Transformation 5】 (In formula (5), R 5 and R 6 Each is independently a hydrogen atom, an unsubstituted linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, an aromatic alkyl group having 7 to 30 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an acyl group having 1 to 11 carbon atoms, or an aryl group having 6 to 30 carbon atoms, R 5 and R 6 At least one of them is an alkyl group having 8 or more carbon atoms, OR 5 and OR 6 These groups may be bonded to each other via alkylene groups or carbonyl groups to form a cyclic structure, and the alkylene groups may be substituted with hydroxyl groups, phosphate groups, amino groups, alkoxy groups, or ester groups, and carbonyl groups may be inserted into the main chain. 【Transformation 6】

Images