JP2024067306A - Alicyclic polycarbonate and method for producing same - Google Patents

Abstract

[Problem] To provide an alicyclic polycarbonate capable of utilizing a cis-type alicyclic vicinal diol and a method for producing the alicyclic polycarbonate. [Solution] To provide an alicyclic polycarbonate containing a structural unit represented by the following formula (1), and a method for producing an alicyclic polycarbonate comprising ring-opening polymerization of a specific compound with a phosphazene base and a urea to obtain an alicyclic polycarbonate containing a structural unit represented by the following formula (1). JPEG2024067306000024.jpg31170 [Selected Figure] Figure 1

Description

The present invention relates to alicyclic polycarbonates and methods for producing alicyclic polycarbonates.

Alicyclic polycarbonates tend to have better light resistance, transparency, and color tone than aromatic polycarbonate resins such as bisphenol A (see, for example, Patent Document 1). In recent years, alicyclic polycarbonates using raw materials derived from plants and biomass have also been developed. For example, Patent Document 2 discloses a polycarbonate resin that uses isosorbide, which can be derived from starch, as a raw material.

Among these alicyclic polycarbonate resins, polycarbonates that contain a diol (vicinal diol) with one hydroxyl group on each of the adjacent carbon atoms as an alicyclic monomer unit can be synthesized by copolymerization of epoxy and carbon dioxide or by ring-opening polymerization of cyclic carbonates, and are expected to have a wide range of industrial applications.

For example, poly(cyclohexene carbonate) having a six-membered carbon ring can be synthesized by the reaction of cyclohexene oxide with carbon dioxide, as shown in Patent Document 1. It is also known that poly(cyclohexene carbonate) can be obtained by ring-opening polymerization of 1,2-cyclohexene carbonate, as described in Patent Document 2, Non-Patent Document 1, and Non-Patent Document 2.

Japanese Patent No. 5403537 JP 2019-108547 A

Macromolecules 2014, 47, 4230-4235. Polymer Journal 2013, 45, 1183-1187.

However, the alicyclic polycarbonates synthesized so far have had trans-type alicyclic vicinal diols as monomer units, whereas cis-type alicyclic vicinal diols are difficult to polymerize due to their low reactivity, and no polycarbonates containing cis-type alicyclic vicinal diols as monomer units have been known.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an alicyclic polycarbonate capable of utilizing a cis-alicyclic vicinal diol and a method for producing an alicyclic polycarbonate.

The present invention includes the following embodiments.
＜1＞
An alicyclic polycarbonate comprising a structural unit represented by the following formula (1):
(In formula (1), A is an optionally substituted alicyclic moiety.)
＜2＞
The alicyclic polycarbonate according to <1>, wherein the content of the structural unit represented by the formula (1) is 5 to 40 mol %.
＜3＞
The alicyclic polycarbonate according to <1> or <2>, wherein the structural unit represented by the formula (1) is a structural unit represented by the following formula (1-2):
＜4＞
The alicyclic polycarbonate according to any one of <1> to <3>, further comprising a structural unit represented by the following formula (2):
(In formula (2), B is an optionally substituted alicyclic moiety.)
＜5＞
The alicyclic polycarbonate according to <4>, wherein the content of the structural unit represented by the formula (2) is 60 to 95 mass %.
＜6＞
<5> The alicyclic polycarbonate according to any one of <1> to <5>, having a weight average molecular weight (Mw) of 500 to 10,000.
＜７＞
A method for producing an alicyclic polycarbonate, comprising ring-opening polymerization of a compound represented by the following formula (4) with a phosphazene base and a urea to obtain an alicyclic polycarbonate containing a structural unit represented by the following formula (1):
(A in formula (4) is an optionally substituted alicyclic moiety.)
(In formula (1), A is an optionally substituted alicyclic moiety.)

The present invention provides an alicyclic polycarbonate that can utilize a cis-alicyclic vicinal diol and a method for producing an alicyclic polycarbonate.

FIG. 1 is a ¹³ C-NMR spectrum of the polymer obtained in Example 3. FIG. 2 shows a comparison of the ¹³ C-NMR spectrum of the polymer obtained in Example 3 and the polymer obtained in Polymerization Example 1.

The following describes in detail the form for carrying out the present invention (hereinafter, also referred to as the "present embodiment"). Note that the present invention is not limited to the present embodiment, and can be carried out in various modifications within the scope of the gist of the present invention. In this specification, a numerical range indicated using "~" indicates a range that includes the numerical values before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this specification, the upper limit or lower limit of a numerical range of a certain stage can be arbitrarily combined with the upper limit or lower limit of a numerical range of another stage.

[Alicyclic polycarbonate]
The alicyclic polycarbonate according to this embodiment contains a structural unit represented by the following formula (1).
(In formula (1), A is an optionally substituted alicyclic moiety (hereinafter also referred to as "alicyclic moiety A").)
According to the present embodiment, it is possible to provide an alicyclic polycarbonate capable of utilizing a cis-alicyclic vicinal diol and a method for producing an alicyclic polycarbonate.

In the alicyclic polycarbonate according to the present embodiment, in the structural unit represented by formula (1) as shown below, the bond between the alicyclic portion of A and the carbonate group (the bond indicated by the arrow in formula (i) below) is of cis type. Note that the carbon indicated by the arrow can be an asymmetric carbon, and in that case, it may be either R or S, but for convenience, it is represented as formula (1) to represent the cis type.

In formula (1), the substituents that can be substituted on the alicyclic moiety A are not particularly limited, but examples include a hydroxyl group, a phosphate group, an amino group, a vinyl group, an aryl group, an alkoxy group, an aryloxy group, an ester group, an acyl group, an acyloxy group, and an alkyl group. The substituents may be one or more.

The phosphate group and amino group may be unsubstituted or substituted. That is, the phosphate group and amino group may be monosubstituted or disubstituted. Substituents for the phosphate group and amino group include alkyl groups having 1 to 6 carbon atoms, or aryl groups having 6 to 20 carbon atoms.

The number of carbon atoms in the aryl group is preferably 6 to 20, more preferably 6 to 18, and more preferably 6 to 15. The aryl group is not particularly limited, but examples thereof include a phenyl group, a tolyl group, a xylyl group, a trimethylphenyl group, a cumenyl group, a biphenyl group, and a naphthyl group.

The number of carbon atoms in the alkoxy group is preferably 1 to 20, more preferably 1 to 18, and more preferably 1 to 15. Examples of the alkoxy group include, but are not limited to, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a cyclopentyloxy group, a hexyloxy group, a cyclohexyloxy group, a heptyloxy group, an octyloxy group, a nonanyloxy group, a decyloxy group, a vinyloxy group, and a benzyloxy group.

The number of carbon atoms in the aryloxy group is preferably 6 to 20, more preferably 6 to 18, and more preferably 6 to 15. The aryloxy group is not particularly limited, but examples thereof include a phenoxy group and a naphthoxy group.

The number of carbon atoms in the ester group is preferably 3 to 20, more preferably 3 to 18, and more preferably 3 to 15. The ester group is not particularly limited, but examples thereof include a methyl ester group, an ethyl ester group, a propyl ester group, a butyl ester group, a pentyl ester group, a cyclopentyl ester group, a hexyl ester group, a cyclohexyl ester group, a heptyl ester group, an octyl ester group, a nonanyl ester group, a decyl ester group, a phenyl ester group, a benzyl ester group, a vinyl ester group, and an allyl ester group.

The number of carbon atoms in the acyl group is preferably 2 to 20, more preferably 2 to 18, and more preferably 2 to 15. The acyl group is not particularly limited, but examples thereof include a formyl group, an acetyl group, a propionyl group, a butyryl group, a valeryl group, and a benzoyl group.

The number of carbon atoms in the acyloxy group is preferably 2 to 20, more preferably 2 to 18, and more preferably 2 to 15. Examples of the acyloxy group include, but are not limited to, a formyloxy group, an acetyloxy group, a propionyloxy group, a butyryloxy group, a valeryloxy group, and a benzoyloxy group.

The number of carbon atoms in the alkyl group is preferably 1 to 20, more preferably 1 to 18, and preferably 1 to 15. The alkyl group may be a linear, branched, or cyclic alkyl group. Examples of the alkyl group include, but are not limited to, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, a cyclopentyl group, an n-hexyl group, a cyclohexyl group, an n-heptyl group, an n-octyl group, an n-nonanyl group, an n-decyl group, and a benzyl group.

The alicyclic polycarbonate according to this embodiment preferably has a structural unit represented by formula (1) that does not have a substituent.

The substituents in the alicyclic polycarbonate according to this embodiment may be bonded together to form a ring structure.

The number of carbon atoms in the alicyclic moiety A is preferably 5 to 20, more preferably 5 to 16, and preferably 6 to 10. The alicyclic moiety A is not particularly limited, but may be a saturated or unsaturated cycloalkane, such as a structure represented by cyclopropane, cyclopropene, cyclobutane, cyclobutene, cyclopentane, cyclopentene, cyclohexane, cyclohexene, cycloheptane, cycloheptene, cyclooctane, cyclooctene, cyclononane, cyclononene, cyclodecane, cyclodecene, norbornene, or tetracyclodecane, and is preferably cyclohexane, cyclohexene, cycloheptane, or cycloheptene.

Among the above, the alicyclic polycarbonate according to this embodiment preferably has a structural unit represented by formula (1-2).

In the alicyclic polycarbonate according to this embodiment, the ratio of the structural unit represented by formula (1) is preferably 0.01 to 100 mol %, more preferably 5 to 50 mol %, and even more preferably 5 to 40 mol %, based on all the monomer components constituting the alicyclic polycarbonate.

The alicyclic polycarbonate according to this embodiment may be a homopolymer having the structural unit represented by formula (1) as a repeating unit, or a copolymer containing other structural units in addition to the structural unit represented by formula (1).

Other structural units may include monomer units such as trans-carbonate, ester, and ether.

The alicyclic polycarbonate according to this embodiment preferably further contains a structural unit represented by formula (2).
(In formula (2), B is an optionally substituted alicyclic moiety (hereinafter, referred to as "alicyclic moiety B").)
The substituents which may be substituted on the alicyclic moiety B are the same as those given above for A. The substituents may be one or more. The alicyclic moiety B is the same as those given above for B.

The bond between the alicyclic portion of B and the carbonate group is a trans type. The carbon at the bond can be an asymmetric carbon, and in that case, it can be either R or S, but for convenience, it is represented as in formula (2) to represent the trans type.

In the alicyclic polycarbonate according to this embodiment, the ratio of the structural unit represented by formula (2) is preferably 0.01 to 100 mol %, more preferably 50 to 95 mol %, and even more preferably 60 to 95 mol %, based on all the monomer components constituting the alicyclic polycarbonate.

The terminal structure of the alicyclic polycarbonate according to this embodiment is not limited, but may be, for example, a hydrogen group, a hydroxyl group, an alkyl group, a vinyl group, an amide group, an ester group, a phosphate group, or an alkoxy group.

The weight average molecular weight (Mw) of the alicyclic polycarbonate according to this embodiment, measured by gel permeation chromatography using polystyrene as a standard sample, is 500 to 500,000, and preferably 500 to 10,000. The weight average molecular weight is a polystyrene-equivalent value measured by gel permeation chromatography, and can be measured specifically by the method described in the examples.

In order to set the weight average molecular weight (Mw) of the alicyclic polycarbonate according to this embodiment within the above range, the ratio of the polymerizable monomer and the polymerization initiator may be appropriately adjusted, and the polycarbonate resin may be produced by the production method described below. By reducing the ratio of the polymerization initiator to the polymerizable monomer, the weight average molecular weight tends to be increased. Furthermore, by extending the polymerization time, the weight average molecular weight tends to be increased. Furthermore, by stirring using a stirring blade, the Mw tends to be increased.

The alicyclic polycarbonate according to this embodiment can be used as various materials, for example, as various optical materials such as optical lens materials, optical devices, materials for optical components, and display materials.

[Method of producing alicyclic polycarbonate]
A preferred method for producing the polycarbonate according to the present embodiment includes, for example, ring-opening polymerization of a compound represented by the following formula (4) (hereinafter also referred to as “alicyclic cyclic carbonate (4)”) using a phosphazene base and a urea to obtain an alicyclic polycarbonate containing a structural unit represented by formula (1).
(In formula (4), A is an optionally substituted alicyclic moiety.)

The method for producing the polycarbonate according to the present embodiment may be a method for obtaining an alicyclic polycarbonate by a transesterification method in which a compound represented by the following formula (5) is reacted with a carbonyl compound such as a dialkyl carbonate, phosgene, or urea in the presence of a catalyst, but is preferably a production method by ring-opening polymerization of an alicyclic cyclic carbonate.
(In formula (5), A is an optionally substituted alicyclic moiety, and R is hydrogen, a linear or branched alkyl group having 1 to 20 carbon atoms, or an acyl group having 1 to 20 carbon atoms.)

(Method for producing alicyclic cyclic carbonate)
The method for synthesizing the alicyclic cyclic carbonate (4) used in the ring-opening polymerization is not particularly limited. For example, the alicyclic cyclic carbonate (4) can be obtained by reacting a compound represented by formula (6) with a halogenated formate ester, a carbonate ester, urea, phosgene, or the like.
(In formula (6), A is an optionally substituted alicyclic moiety.)

Examples of halogenated formates include, but are not limited to, methyl chloroformate, ethyl chloroformate, methyl bromoformate, ethyl bromoformate, methyl iodoformate, and ethyl iodoformate. Examples of carbonates include, but are not limited to, dimethyl carbonate, diethyl carbonate, propyl carbonate, isopropyl carbonate, butyl carbonate, isobutyl carbonate, and diphenyl carbonate.

In the method for synthesizing cyclic carbonates using halogenated formates, the reaction temperature is preferably -30 to 50°C, more preferably 0 to 10°C. The reaction pressure is preferably atmospheric pressure, and the reaction time is preferably 1 to 24 hours, more preferably 6 to 12 hours. The reaction is preferably carried out in an inert gas atmosphere such as an argon atmosphere or a nitrogen atmosphere.

The reaction can be carried out by conventional methods such as batch, semi-batch, or continuous. After the reaction is completed, the cyclic carbonate can be separated and purified by means of concentration, distillation, extraction, crystallization, recrystallization, ion exchange, silica gel column, etc.

In the method for synthesizing cyclic carbonates using carbonate esters, the catalyst used is not particularly limited, but may be, for example, a metal oxide such as beryllium oxide, magnesium oxide, calcium oxide, strontium oxide, barium oxide, lanthanum oxide, zinc oxide, aluminum oxide, cerium oxide, iron oxide, cobalt oxide, nickel oxide, silicon oxide, copper oxide, or silver oxide; or an organic base such as triethylamine, tripropylamine, tributylamine, tripentylamine, 4-ethylmorpholine, picoline, pyridine, N,N-dimethyl-4-aminopyridine, diazabicycloundecene, dipropylamine, dibutylamine, propylamine, butylamine, morpholine, pyrimidine, imidazole, or aniline, preferably a metal oxide, more preferably an alkaline earth metal oxide such as calcium oxide, magnesium oxide, or barium oxide, and even more preferably calcium oxide.

The alicyclic cyclic carbonate (4) can also be obtained by reacting a compound represented by the following formula (7) (hereinafter also referred to as "cycloalkylene oxide (C2)") with carbon dioxide.
(In formula (7), A is an optionally substituted alicyclic moiety.)

The carbon dioxide used in the reaction with the cycloalkylene oxide (C2) may be in the form of gas, liquid, or solid. It may be pure carbon dioxide or a mixture with compounds inert to other reactions, such as inert gases such as nitrogen, argon, and helium, or with hydrocarbons, or may contain carbon monoxide or a small amount of oxygen or water.

A catalyst is used in the reaction of cycloalkylene oxide (C2) with carbon dioxide, examples of which include porphyrin compounds such as chloro(5,10,15,20-tetra-p-tolylporphyrinato)chromium, amines such as N-methylimidazole, and alkali metal or alkaline earth metal halides, with alkali metal or alkaline earth metal halides being preferred.

Examples of the above-mentioned alkali metals and alkaline earth metals include halides of lithium, sodium, potassium, rubidium, cesium, francium, beryllium, magnesium, calcium, strontium, barium, and radium, and more specifically, lithium fluoride, sodium fluoride, potassium fluoride, rubidium fluoride, cesium fluoride, francium fluoride, beryllium fluoride, magnesium fluoride, calcium fluoride, strontium fluoride, barium fluoride, radium fluoride, lithium chloride, sodium chloride, potassium chloride, rubidium chloride, cesium chloride, francium chloride, beryllium chloride, magnesium chloride, calcium chloride, strontium chloride, barium chloride, radium chloride, lithium bromide, sodium bromide, rubidium bromide, cesium bromide, francium bromide, beryllium bromide, magnesium bromide, and strontium bromide. Examples of the alkali metal halide include compounds of a single metal and a single halogen, such as lithium iodide, barium bromide, radium bromide, lithium iodide, sodium iodide, potassium iodide, rubidium iodide, cesium iodide, francium iodide, beryllium iodide, magnesium iodide, calcium iodide, strontium iodide, barium iodide, and radium iodide; double salts, such as sodium magnesium chloride, potassium magnesium chloride, calcium potassium chloride, and potassium magnesium bromide; and polyhalides, such as potassium bromide bromine, potassium iodine chloride, rubidium iodine chloride, cesium iodine chloride, cesium bromide bromine, rubidium iodine chloride, potassium bromide, cesium iodine bromide, and rubidium iodine bromide. These alkali metal and alkaline earth metal halides may be used alone or in combination of two or more. Among these halides, those containing bromine or iodine are preferred, and iodides are particularly preferred. There are no particular restrictions on the amount of the alkali metal and alkaline earth metal halides used in this embodiment, but it is generally preferred to use them in the range of 0.001 to 1,000 times the amount of the cycloalkylene oxide used.

When using the above-mentioned alkali metal halide or alkaline earth metal halide as a catalyst for this reaction, it is preferable to use a solution of the alkali metal halide or alkaline earth metal halide in cycloalkylene carbonate. Carbon dioxide is usually used in an amount of 0.01 to 1,000 times by mole, preferably 0.1 to 100 times by mole, and more preferably 0.5 to 20 times by mole, based on the amount of cycloalkylene oxide.

The reaction temperature is 50 to 400°C, preferably 100 to 300°C, the reaction is usually carried out under normal pressure or elevated pressure, and the reaction time is several minutes to several tens of hours.

(Polymerization initiator (or polymerization catalyst))
In the alicyclic polycarbonate according to the present embodiment, a phosphazene base and a urea are used to perform ring-opening polymerization of the alicyclic cyclic carbonate (4). The phosphazene base and the urea form a hybrid catalyst.
The phosphazene base is not particularly limited, but examples thereof include:
t-Butylimino-tris(dimethylamino)phosphorane (hereinafter also referred to as "P1-t-Bu"),
t-Butylimino-tri(pyrrolidino)phosphorane (hereinafter also referred to as "P1-t-Bu-tris(tetramethylene)"),
1-t-butyl-2,2,4,4,4-pentakis(dimethylamino)-2λ5,4λ5-catenadi(phosphazene) (hereinafter also referred to as "P2-t-Bu"),
1-ethyl-2,2,4,4,4-pentakis(dimethylamino)-2λ5,4λ5-catenadi(phosphazene) (hereinafter also referred to as "P2-Et"),
1-t-butyl-4,4,4-tris(dimethylamino)-2,2-bis-[tris(dimethylamino)phosphoranylideneamino]-2λ5,4λ5-catenadi(phosphazene) (hereinafter also referred to as "P4-t-Bu"),
2-t-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine (hereinafter also referred to as "BEMP");
etc.

Examples of ureas include urea, thiourea, and guanidine. Examples of ureas include unsubstituted urea, monosubstituted urea, and disubstituted urea.

Examples of monosubstituted ureas include methylurea, ethylurea, propylurea, butylurea, cyclohexylurea, [(tetrahydrofuran-2-yl)methyl]urea, 3-chlorophenylurea, N-benzoylurea, and (4-bromophenyl)urea.

Examples of the disubstituted urea include
1,3-dimethylurea, 1,3-diethylurea, 1,3-diisopropylurea, 1,3-dicyclohexylurea, 1,3-diphenylurea, 1,3-bis[3,5-bis(trifluoromethyl)phenyl]urea,
1-[3,5-bis(trifluoromethyl)phenyl]-3-[2-(dimethylamino)cyclohexy]urea,
1-[3,5-bis(trifluoromethyl)phenyl]-3-[3-(trifluoromethyl)phenyl]urea,
1-[3,5-bis(trifluoromethyl)phenyl]-3-[phenyl]urea,
1-[3,5-bis(trifluoromethyl)phenyl]-3-[cyclohexyl]urea,
1-[3-(trifluoromethyl)phenyl]-3-[phenyl]urea,
1-[cyclohexyl]-3-[phenyl]urea, and the like.

Examples of thiourea include unsubstituted thiourea, methylthiourea, ethylthiourea, propylthiourea, butylthiourea, cyclohexylthiourea, [(tetrahydrofuran-2-yl)methyl]thiourea, 3-chlorophenylthiourea, N-benzoylthiourea, and 1-substituted thiourea such as (4-bromophenyl)thiourea, 1,3-dimethylthiourea, 1,3-diethylthiourea, 1,3-diisopropylthiourea, 1,3-dicyclohexylthiourea, 1,3-diphenylthiourea, and 1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea. Examples of 2-substituted thioureas include 1-[3,5-bis(trifluoromethyl)phenyl]-3-[2-(dimethylamino)cyclohexyl]thiourea, 1-[3,5-bis(trifluoromethyl)phenyl]-3-[3-(trifluoromethyl)phenyl]thiourea, 1-[3,5-bis(trifluoromethyl)phenyl]-3-[phenyl]thiourea, 1-[3,5-bis(trifluoromethyl)phenyl]-3-[cyclohexyl]thiourea, 1-[3-(trifluoromethyl)phenyl]-3-[phenyl]thiourea, and 1-[cyclohexyl]-3-[phenyl]thiourea. Among these, 2-substituted thioureas are preferred.
The ureas may be used alone or in combination with other polymerization initiators, but are preferably used in combination with other polymerization initiators, and more preferably in combination with thiourea and other polymerization initiators.

(Additive)
From the viewpoint of controlling the molecular weight of the resulting polymer and from the viewpoint of expressing various properties by controlling the terminal structure, additives may be used in addition to the above polymerization initiator. The additives are not particularly limited, but examples thereof include monoalcohols such as methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, nonanol, decanol, dodecanol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, 5-norbornene-2-methanol, 1-adamantanol, 2-adamantanol, trimethylsilylmethanol, phenol, benzyl alcohol, and p-methylbenzyl alcohol, dialcohols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexanediol, nonanediol, tetramethylene glycol, and polyethylene glycol, polyhydric alcohols such as glycerol, sorbitol, xylitol, ribitol, erythritol, and triethanolamine, and methyl lactate and ethyl lactate. The above additives may be used alone or in combination of two or more.

(Mixing)
In the method for producing a polycarbonate according to the present embodiment, it is preferable to stir the reactants and/or products in the polymerization step. The stirring method is not particularly limited, but examples thereof include stirring using a mechanical stirrer and agitating blades, and stirring using a magnetic stirrer and a rotor.

(Reaction temperature)
In the method for producing the polycarbonate according to this embodiment, the reaction temperature in the polymerization step is not particularly limited as long as it is within a range in which the polycarbonate of this embodiment can be produced, but is preferably 0° C. or higher and 150° C. or lower, more preferably 0° C. or higher and 130° C. or lower, and even more preferably 0° C. or higher and 120° C. or lower.

(solvent)
In the method for producing a polycarbonate according to the present embodiment, a solvent may or may not be used. The solvent is not particularly limited, but examples thereof 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.

The amount of polymerization initiator used in the polymerization step of the polycarbonate manufacturing method of this embodiment may be adjusted appropriately depending on the target molecular weight of the polycarbonate resin, but is preferably 0.0001 mol% to 10 mol%, and more preferably 0.0002 mol% to 5 mol%, in terms of the amount of substance relative to the cyclic carbonate, which is a ring-opening polymerizable monomer. The above polymerization initiators may be used alone or in combination of two or more types.

In this embodiment, the cyclic carbonate can be quantified by techniques well known to those skilled in the art, such as ¹ H-NMR, ¹³ C-NMR, high performance liquid chromatography, gas chromatography, and the like.

The present embodiment will be described in more detail below with reference to examples, but the present embodiment is not limited to the following examples.

In this example, the measurements were performed as follows:

( ^1H -NMR Measurement)
^{The 1H} -NMR spectrum of the polycarbonate resin was obtained by performing NMR measurement as follows using a JEOL NMR device (product name: ECZ400R) and a TFH probe. The reference peak of the deuterated solvent was 7.26 ppm when chloroform-d was used and 2.50 ppm when dimethylsulfoxide- _d was used, and the measurement was performed with 8 integration times.

( ^13C -NMR Measurement)
The NMR spectrum of polycarbonate was obtained by performing NMR measurement as follows using a JEOL Ltd. NMR device (product name: ECZ400R) and a TFH probe. The reference peak of the deuterated solvent was ^77.16 ppm when chloroform-d was used and 39.52 ppm when dimethylsulfoxide- _d was used, and the measurement was performed with 256 accumulations.

(Conversion rate)
The conversion rate (x _t ) of T6C was calculated from the integral value A _mt of the peak (4.01 to 4.07 ppm) derived from the methine proton of the ^monomer and the integral value A _pt of the peaks (4.56 ppm, 4.29 ppm) derived from the methine signal of the polymer in the 1 H-NMR spectrum of the crude product according to the following formula:

The total monomer conversion rate x was calculated from the integral value _Am of the peaks (near 155 ppm) derived from the carbonyl carbons of both monomers in the C-NMR spectrum of the crude product and the integral value _Ap of the peaks (near ¹⁵⁴ ppm) derived from the carbonyl carbons of both units in the polymer according to the following formula:

The conversion rate _xc of C6C was calculated according to the following formula using the conversion rate x of the total monomers and the conversion rate _xt of T6C.

In the above, [M] ₀ represents the initial concentration of the total monomers, [T6C] ₀ represents the initial concentration of T6C, and [C6C] ₀ represents the initial concentration of C6C.

(Measurement of weight average molecular weight (Mw) and number average molecular weight (Mw))
A solution in which tetrahydrofuran was added at a ratio of 2.0 g to 0.02 g of polycarbonate was used as a measurement sample, and the weight average molecular weight of the polycarbonate resin was measured using a high-speed GPC device (manufactured by Tosoh Corporation, product name "HLC-8420GPC"). As the column, TSK guard columns SuperH-H, TSKgel SuperHM-H, TSKgel SuperHM-H, TSKgel SuperH2000, and TSKgel SuperH1000 (all product names manufactured by Tosoh Corporation) manufactured by Tosoh Corporation were connected in series and used. The column temperature was 40°C, and tetrahydrofuran was used as the mobile phase, and analysis was performed at a rate of 0.60 mL/min. An RI detector was used as the detector. A calibration curve was prepared using polystyrene standard samples (molecular weights: 2520000, 1240000, 552000, 277000, 130000, 66000, 34800, 19700, 8680, 3470, 1306, 370) manufactured by Polymer Standards Service as standard samples. Based on the calibration curve thus prepared, the number average molecular weight and weight average molecular weight of the polycarbonate resin were determined.

[Synthesis Example 1: Synthesis of cis-1,2-cyclohexene carbonate: C6C 1]
Cyclohexene oxide (Tokyo Chemical Industry, 40.0 g, 406 mmol) and potassium iodide (0.162 g, 0.976 mmol) were charged into a 1 L autoclave, and carbon dioxide was pressurized to 4.0 MPa (30° C.), and then the mixture was heated at 200° C. for 4 days. After that, the mixture was fractionally distilled under reduced pressure at 0.2 to 0.3 hPa and 120° C. to obtain the target cis-1,2-cyclohexene carbonate (13.7 g, 96.4 mmol, yield 24%).

[Synthesis Example 2: Synthesis of cis-1,2-cyclohexene carbonate: C6C 2]
Under an argon atmosphere, diphenyl carbonate (Tokyo Chemical Industry, 1.66 g, 7.74 mmol) and 2-methyl THF (Tokyo Chemical Industry, 10 ml) were added to a 50 mL four-neck flask, and cis-1,2-cyclohexanediol (Tokyo Chemical Industry, 1.00 g, 8.61 mmol) and 1,5,7-triazabicyclo[4.4.0]deca-5-ene (TBD, Tokyo Chemical Industry, 21.5 mg, 0.155 mmol) were further added while stirring, and the mixture was stirred at room temperature for 19 hours. After the reaction, one drop of acetic acid was added to quench the reaction, and the reaction solution was concentrated to obtain 2.94 g of a pale yellow transparent liquid. The pale yellow transparent liquid was purified by silica gel column chromatography to obtain the desired cis-1,2-cyclohexene carbonate (0.758 g, 5.33 mmol, yield 69%).

[Synthesis Example 3: Synthesis of cis-1,2-cyclohexene carbonate: C6C 3]
Cis-1,2-cyclohexanediol (Tokyo Chemical Industry Co., Ltd., 1.21 g, 10.4 mmol) and dehydrated THF (30 mL) were added to a 50 mL three-neck flask under a nitrogen stream. The flask was immersed in an ice bath and stirred while cooling so that the internal temperature was 5°C or less, and ethyl chloroformate (FUJIFILM Wako Pure Chemical Industries, Ltd., 3.68 g, 33.9 mmol) and triethylamine (FUJIFILM Wako Pure Chemical Industries, Ltd., 3.61 g, 35.6 mmol) were added dropwise to the reaction solution in two batches and stirred, and the mixture was stirred at room temperature for 11 hours. After quenching by adding ethanol (FUJIFILM Wako Pure Chemical Industries, Ltd., 0.82 g), the by-product white solid was removed by vacuum filtration, and the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography to obtain the desired cis-1,2-cyclohexene carbonate (1.07 g, 7.52 mmol, yield 78%).

[Synthesis Example 4: Synthesis of trans-1,2-cyclohexene carbonate: T6C]
Under a nitrogen stream, trans-1,2-cyclohexanediol (BLD PHARMATECH 25.0 kg, 215.2 mol) and THF (containing stabilizer) (250 L) were added to a 1000 L reaction vessel. The reaction vessel was cooled to -6°C while stirring, and a solution of ethyl chloroformate (70.0 kg, 645 mol) and triethylamine (87.4 kg, 863 mol) diluted with dehydrated toluene (188 L) was added dropwise to the reaction liquid in two batches overnight and stirred, and then stirred for another 4 hours. The by-product white solid was removed by vacuum filtration, and the filtrate was concentrated under reduced pressure. The residue was dissolved by adding THF/toluene (2/1) (60.0 L) and purified by silica gel column chromatography. The eluent was further concentrated, dissolved in 270 kg of chloroform, and then washed twice with 217 kg of ion-exchanged water. Thereafter, reprecipitation was carried out with 20 kg of chloroform and 100 L of heptane, and then the mixture was concentrated to obtain the target trans-cyclohexene carbonate (22.81 kg, 160.5 mol, yield 75%).

[Synthesis Example 5: Synthesis of 1-[3,5-bis(trifluoromethyl)phenyl]-3-[cyclohexyl]thiourea]
Cyclohexylamine (0.42 mL, 3.70 mmol) was slowly added to a solution of 3,5-bis(trifluoromethyl)phenylisothiocyanate (Tokyo Chemical Industry, 0.68 mL, 3.70 mmol) in THF (4 mL). The mixture was stirred at 30°C for 2 hours, and then THF was distilled off under reduced pressure. The resulting white solid was washed four times with 10 ml of n-hexane and dried to obtain the target product (1.34 g, 3.62 mmol, yield: 98%).

[Polymerization Example 1: Anionic ring-opening polymerization of T6C]
In a 25 mL ground test tube, trans-1,2-cyclohexene carbonate: T6C (0.30 g, 2.11 mmol) was added, and the inside of the test tube was replaced with nitrogen. The test tube was heated to 60°C, and benzyl alcohol (9.13 x 10 ^-3 g, 8.44 x 10 ^-5 mol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (12.8 x 10 ^-3 g, 8.44 x 10 ^-5 mol) were added, and the mixture was stirred at 60°C for 14 hours. After 14 hours, acetic acid (7.63 x 10 ^-3 g, 1.27 x 10 ^-4 mol) was added to stop the reaction. The test tube was allowed to cool to room temperature, and then a small amount of chloroform was added to dissolve the contents. The resulting solution was dropped into 40 mL of petroleum ether to precipitate the polymer. The precipitated polymer was collected, redissolved in chloroform, and then reprecipitated by dropping into 40 mL of petroleum ether. The polymer was collected by filtration under reduced pressure and dried at 40° C. in a vacuum to obtain a polymer.

[Example 1]
To a 25 mL ground test tube were added cis-1,2-cyclohexene carbonate: CC (0.15 g, 1.06 mmol), trans-1,2-cyclohexene carbonate: T6C (0.15 g, 1.06 mmol), and 1-[3,5-bis(trifluoromethyl)phenyl]-3-[cyclohexyl]thiourea (23 mg, 6.21 × 10 ^-2 mmol), and the atmosphere inside the test tube was replaced with nitrogen. The test tube was heated to 60°C, and benzyl alcohol: BnOH (2.28 mg, 2.11 x ^10-2 mmol) and 1-t-butyl-4,4,4-tris(dimethylamino)-2,2-bis-[tris(dimethylamino)phosphoranylideneamino]-2λ5,4λ5-catenadi(phosphazene): t-Bu-P4 in 0.8 M hexane solution (26 μL, 2.11 x ^10-2 mmol) were added, followed by stirring at 60°C for 14 hours. After 14 hours, acetic anhydride (3.24 mg, 3.17 x ^10-2 mmol) was added to stop the reaction. The test tube was allowed to cool to room temperature, and then a small amount of chloroform was added to dissolve the contents. The resulting solution was dropped into 40 mL of petroleum ether to precipitate the polymer. The precipitated polymer was collected, added to chloroform to dissolve again, and then dropped into 40 mL of petroleum ether to cause reprecipitation. The polymer was recovered by vacuum filtration and dried in vacuum at 40° C. to give 0.15 g of copolymer.

[Examples 2 to 4]
In the same manner, the reaction time and the amount of monomer charged were changed to carry out Examples 2 to 4. In the same manner, the reaction time and the amount of monomer charged were changed to carry out Examples 2 to 4.
The ¹³ C-NMR spectrum of the polymer obtained in Example 3 is shown in Figure 1. Figure 2 shows ^{the 13} C-NMR spectrum of the polymer obtained in Example 3 and the polymer obtained in Polymerization Example 1.

Claims (7)

An alicyclic polycarbonate comprising a structural unit represented by the following formula (1):
(In formula (1), A is an optionally substituted alicyclic moiety.) The alicyclic polycarbonate according to claim 1, wherein the content of the structural unit represented by the formula (1) is 5 to 40 mol% based on all monomer components constituting the alicyclic polycarbonate. The alicyclic polycarbonate according to claim 1, wherein the structural unit represented by formula (1) is a structural unit represented by the following formula (1-2):
The alicyclic polycarbonate according to claim 1 or 2, further comprising a structural unit represented by the following formula (2):
(In formula (2), B is an optionally substituted alicyclic moiety.) The alicyclic polycarbonate according to claim 4, wherein the content of the structural unit represented by the formula (2) is 60 to 95 mol% based on all monomer components constituting the alicyclic polycarbonate. The alicyclic polycarbonate according to claim 5, having a weight average molecular weight (Mw) of 500 to 10,000. A method for producing an alicyclic polycarbonate, comprising ring-opening polymerization of a compound represented by the following formula (4) with a phosphazene base and a urea to obtain an alicyclic polycarbonate containing a structural unit represented by the following formula (1):
(A in formula (4) is an optionally substituted alicyclic moiety.)
(In formula (1), A is an optionally substituted alicyclic moiety.)