Method for producing polycarbonate compound

Abstract

This method for producing a polycarbonate compound comprises generating a polycarbonate compound by causing a raw material containing a carbonyl compound represented by general formula (1) to undergo a polymerization reaction in the presence of a metal salt catalyst. In the method, the metal salt catalyst is set to exist in a solid state in a reaction system of the polymerization reaction.　In general formula (1), R1 represents an alkyl group or a cycloalkyl group. R2 represents a hydrogen atom, an alkoxycarbonyl group, or a cycloalkoxycarbonyl group. L represents a divalent organic group. n represents an integer of one or more.

Description

Method for producing polycarbonate compounds

[0001] The present invention relates to a method for producing a polycarbonate compound.

[0002] Polycarbonate compounds are excellent in transparency, heat resistance, mechanical strength, etc., and are widely used in electronic components, automobile components, optical lenses, etc. Polycarbonate compounds are generally obtained by reacting a dihydroxy compound with a carbonate diester compound in the presence of a polymerization catalyst. Metal salts or the like are used as the polymerization catalyst. For example, Patent Document 1 describes the production of polycarbonate compounds by melt polymerization in which a polymerization catalyst such as calcium acetate or magnesium acetate is added to a reaction system in the form of a solution.

[0003] Japanese Patent Application Laid-Open No. 2014-9332

[0004] The present inventors have conducted extensive research to improve the functionality of polycarbonate compounds and to achieve a higher degree of polymerization in their synthesis reactions. As a result, they have found that in conventional reaction systems in the presence of a polymerization catalyst, there are limitations to improving the degree of polymerization of the resulting polycarbonate, and that a certain degree of decomposition (side reaction) of the polycarbonate also occurs, limiting the improvement of transparency. An object of the present invention is to provide a method for producing a polycarbonate compound that can further increase the degree of polymerization of the resulting polycarbonate compound and effectively prevent coloration.

[0005]

[0005] In view of the above problems, the present inventors have conducted extensive research and found that by using a metal salt as a polymerization catalyst to obtain a polycarbonate compound, and by having this metal salt present in a solid state in a reaction system and subjecting a monomer (including a prepolymer) raw material to a polymerization reaction in the presence of a solid catalyst, the degree of polymerization of the resulting polycarbonate compound can be effectively increased and coloration can also be effectively suppressed. The present invention was completed through further research based on these findings.

[0006] The above-mentioned problems of the present invention are solved by the following means: [1] A method for producing a polycarbonate compound, comprising polymerizing a raw material containing a carbonyl compound represented by the following general formula (1) in the presence of a metal salt catalyst, and causing the metal salt catalyst to be present in a solid state in a reaction system of the polymerization reaction: In general formula (1), R １ represents an alkyl group or a cycloalkyl group. ２represents a hydrogen atom, an alkoxycarbonyl group, or a cycloalkoxycarbonyl group. L represents a divalent organic group. n is an integer of 1 or more. [2] The method for producing a polycarbonate compound according to [1], wherein the metal cation constituting the metal salt catalyst is selected from magnesium ions, sodium ions, potassium ions, cesium ions, calcium ions, aluminum ions, and lithium ions. [3] The method for producing a polycarbonate compound according to [2], wherein the metal cation constituting the metal salt catalyst is a magnesium ion. [4] The method for producing a polycarbonate compound according to any one of [1] to [3], wherein the metal salt catalyst is a metal salt of an organic anion. [5] The method for producing a polycarbonate compound according to [4], wherein the organic anion has 3 or more carbon atoms. [6] The method for producing a polycarbonate compound according to [4] or [5], wherein the anion moiety of the organic anion is selected from carboxylate anions, sulfonate anions, phosphate anions, phosphonate anions, and sulfinyl anions. [7] A method for producing a polycarbonate compound according to any one of [4] to [6], wherein the organic anion has 5 or more carbon atoms and the anion moiety of the organic anion is a carboxylate anion. [8] A method for producing a polycarbonate compound according to any one of [4] to [7], wherein the organic anion has a branched structure. [9] A method for producing a polycarbonate compound according to any one of [1] to [8], wherein the metal salt catalyst has an organic polymer structure.

[10] A method for producing a polycarbonate compound according to [9], wherein the organic polymer structure has a crosslinked structure.

[11] A method for producing a polycarbonate compound according to [9] or

[10] , wherein the metal salt catalyst is a metal salt formed by ionic bonding between an organic polymer anion and a metal cation.

[12] A method for producing a polycarbonate compound according to

[11] , wherein the anion moiety of the organic polymer anion is a carboxylate anion.

[13] A method for producing a polycarbonate compound according to any one of [4] to [6], wherein the organic anion in the general formula (1) is R １

[13] The method for producing a polycarbonate compound according to any one of [1] to

[12] , wherein is methyl, ethyl, propyl, or butyl.

[0007] In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0008] According to the method for producing a polycarbonate compound of the present invention, the degree of polymerization of the obtained polycarbonate compound can be further increased, and coloration can also be effectively prevented.

[0009] [Method for Producing Polycarbonate Compounds] In the method for producing polycarbonate compounds of the present invention (hereinafter referred to as the "production method of the present invention"), a metal salt catalyst is used as a polymerization catalyst. In the production method of the present invention, a polycarbonate compound is produced by polymerizing a raw material containing a carbonyl compound of a specific structure in the presence of this metal salt catalyst. A characteristic technical element of the production method of the present invention is that the metal salt catalyst is present in a solid state in the reaction system (reaction solution) during this polymerization reaction. In the present invention, the term "metal salt catalyst" refers to a catalyst having a structural moiety formed by ionic bonding between a metal cation and an anion. The production method of the present invention will now be described in detail.

[0010] <Metal Salt Catalyst> In the production method of the present invention, one or more metal salt catalysts are used as the polymerization catalyst. The metal cation constituting the metal salt catalyst is preferably selected from magnesium ion, sodium ion, potassium ion, cesium ion, calcium ion, aluminum ion, and lithium ion, more preferably magnesium ion, sodium ion, calcium ion, aluminum ion, and lithium ion, and even more preferably magnesium ion.

[0011] In the production method of the present invention, the metal salt catalyst is present in a solid state in the polymerization reaction system. That is, in the production method of the present invention, the metal salt catalyst functions as an insoluble solid catalyst. The presence of the metal salt catalyst in a solid state in the reaction system can be confirmed by visually observing the reaction solution under the reaction conditions of the polymerization reaction. For example, in a batch reaction, if a reaction solution containing the dissolved or molten raw materials and the metal salt catalyst is allowed to stand under the reaction conditions and a precipitate forms or a suspension (slurry) with dispersed solid particles forms, it can be determined that the metal salt catalyst is present in a solid state in the reaction system. Note that if the precipitate or suspension state can be visually confirmed, the metal salt catalyst is present in a solid state in the reaction system, even if a portion of the metal salt catalyst introduced into the reaction system is dissolved. The solid (particles, powder, etc.) in the reaction solution can be confirmed to be the metal salt catalyst by, for example, filtering the reaction solution through a filter and analyzing the residue on the filter using attenuated total reflection infrared spectroscopy (ATR-IR) or solid-state nuclear magnetic resonance (NMR), etc. Furthermore, when the insolubilized metal salt catalyst is packed in a column and subjected to a flow reaction as described below, the metal salt catalyst is also present in a solid state in the reaction system.

[0012] In order to make the metal salt catalyst present in a solid state in the polymerization reaction system, for example, a polymeric inorganic anion can be used as a carrier, and the polymeric inorganic anion and a metal cation can be bound by an ionic bond to form the metal salt catalyst. In this case, the combination of the metal cation and the polymeric inorganic anion is the "metal salt catalyst" in the present invention. In addition, in the present invention, when an anionic group is introduced into a polymeric inorganic compound by surface treatment of the polymeric inorganic compound, even if the anionic group has an organic group, the resulting metal salt is understood to be a metal salt of the polymeric inorganic anion (inorganic metal salt).

[0013] Alternatively, a metal salt can be supported on a polymeric inorganic compound by bonding a metal cation in the form of a metal salt (a neutralized state in which the cationic charge and the anionic charge are balanced) to a polymeric inorganic compound, rather than using the metal cation itself. The metal salt is preferably a metal salt of an organic anion, and the organic anion is preferably a low-molecular-weight organic anion, as described below. Such a metal salt supported on a polymeric inorganic compound, including the polymeric inorganic compound, falls under the "metal salt catalyst" of the present invention. Furthermore, in the present invention, when the metal salt has an organic anion as the anion, the entire system, including the polymeric inorganic compound, is considered to be a metal salt of an organic anion (organic metal salt). Examples of bonding modes between the metal salt and the polymeric inorganic compound include physical adsorption and coordinate bonding.

[0014] Preferred examples of the polymeric inorganic compound include silica, zeolite, alumina, bentonite, cerium oxide, silicone resin, montmorillonite, activated carbon, and diatomaceous earth. These polymeric inorganic compounds may be subjected to a desired surface treatment, surface chemical modification, or the like, as necessary. For example, by introducing an anionic group onto the surface of the polymeric inorganic compound, the polymeric inorganic compound can be used as a source of the polymeric inorganic anion. Furthermore, by introducing a group having a coordinating atom for the metal atom of a metal salt onto the surface of the polymeric inorganic compound, it becomes possible to form a coordinate bond with the metal of the metal salt. Examples of the coordinating atom include a nitrogen atom, an oxygen atom, a sulfur atom, a phosphorus atom, and a halogen atom, with a nitrogen atom being preferred.

[0015] In order to allow the metal salt catalyst to exist in a solid state in the polymerization reaction system, it is also preferable that the metal salt catalyst have an organic polymer structure. For example, a metal salt formed by ionic bonding between an organic polymer anion and a metal cation can be used as the metal salt catalyst. In this case, when the metal cation is a polyvalent cation, the metal cation may be ionic bonded to multiple anion moieties of the organic polymer anion. Furthermore, when the metal cation is a polyvalent cation, the metal cation may be ionic bonded to the organic polymer anion and also to a low-molecular-weight anion.

[0016] Furthermore, instead of the metal cation itself, the metal salt (in a neutralized state where the cationic charge and the anionic charge are balanced) can be bonded to the organic polymer compound. Specifically, an organic polymer compound having a coordinating atom for the metal atom of the metal salt can be coordinately bonded to the metal atom of the metal salt and used as the metal salt catalyst. This metal salt is preferably a metal salt of an organic anion, and this organic anion is preferably a low-molecular-weight organic anion described below. Examples of the coordinating atom include a nitrogen atom, an oxygen atom, a sulfur atom, a phosphorus atom, and a halogen atom, with a nitrogen atom being preferred. In this way, an organic polymer compound coordinately bonded to the metal atom of the metal salt, including the organic polymer compound coordinately bonded, is the "metal salt catalyst" of the present invention.

[0017] In order to ensure that the metal salt catalyst is present in a solid state in the polymerization reaction system, it is preferable that both the organic polymer anion and the organic polymer compound having a coordinating atom for the metal atom of the metal salt have a crosslinked structure. Suitable examples of the organic polymer anion and the organic polymer compound include those having an addition polymerization structure formed by addition polymerization of carbon-carbon double bonds or those having an organopolysiloxane structure (silicone structure), with those having an addition polymerization structure being preferred. The molecular weight or degree of polymerization of the organic polymer anion and the organic polymer compound are not particularly limited, and they may be appropriately designed so as to be present in a solid state in the polymerization reaction system.

[0018] As described above, even if the metal salt catalyst does not contain a polymeric inorganic anion, a polymeric inorganic compound having a coordinating atom for the metal atom of the metal salt, an organic polymer anion, or an organic polymer compound having a coordinating atom for the metal atom of the metal salt, it is possible to have the metal salt catalyst present in a solid state in the polymerization reaction system, depending on the combination of the raw materials containing the carbonyl compound, the solvent, etc. used. Therefore, the metal salt catalyst may be, for example, a metal salt of a low-molecular-weight (non-polymer) organic anion. In the low-molecular-weight organic anion, the chemical composition of the structural portion other than the anion portion is not particularly limited as long as the metal salt catalyst can be present in a solid state in the polymerization reaction system. For example, it may have a hydrocarbon structure (preferably an aliphatic hydrocarbon structure). This low-molecular-weight organic anion preferably has 3 or more carbon atoms, more preferably 4 or more, even more preferably 5 or more, and even more preferably 6 or more. The carbon number is preferably 4 to 30, more preferably 5 to 30, and even more preferably 6 to 25. The low-molecular-weight organic anion preferably has a branched structure. For example, a metal salt (preferably a magnesium salt) of isostearic acid is preferred as the metal salt catalyst.

[0019] In the metal salt catalyst, the anion moiety of the anion is preferably selected from a carboxylate anion, a sulfonate anion, a phosphate anion, a phosphonate anion, and a sulfinyl anion. In the present invention, the terms carboxylate anion, sulfonate anion, phosphate anion, phosphonate anion, and sulfinyl anion are used to indicate the structure of the anion moiety. For example, a carboxylate anion is *-COO － , sulfonate anion is *-SO ３ － (* denotes a linking moiety). The anion moiety of the anion of the metal salt catalyst is preferably a carboxylate anion. For example, when the metal salt catalyst is a metal salt of an organic anion and the organic anion is an organic polymer anion, the organic polymer anion preferably has a carboxylate anion as the anion moiety.

[0020] Specific examples of anions that can constitute the metal salt catalyst are shown below, but the present invention is not limited to these examples except as specified in the present invention. Me is methyl, and R is a substituent (e.g., an alkyl group). The brackets represent repeating units, and m, n, and r are the numbers of repeating units and are any natural numbers.

[0021]

[0022] Two examples of ionic bonds between a magnesium ion and an anion are shown below. In a similar manner to these examples, ionic bonds can be formed between various metal cations and various anion species.

[0023]

[0024] Next, in the case where the metal salt catalyst comprises a magnesium salt and an organic polymer compound that forms a coordinate bond with magnesium, examples of this organic polymer compound are shown below, but the present invention is not limited to these examples except as defined in the present invention.

[0025]

[0026] Two examples of the state in which an organic polymer is coordinated to a metal salt are shown below. Similar to these examples, various complexes can be formed by coordinate bonds between various metal salts and various organic polymer compounds having coordination atoms. X is a monovalent anion, and MgX ２ is, for example, magnesium acetate.

[0027]

[0028] In the production method of the present invention, by having the above-mentioned metal salt catalyst present in a solid state in the polymerization reaction system (acting as a solid catalyst), the degree of polymerization of the resulting polycarbonate compound can be further increased and coloration can be effectively prevented. The reason for this is unclear, but one possible reason is that the catalyst has difficulty reacting with reactive groups (functional groups) present inside the polymer (polycarbonate or its precursor polymer) produced in the reaction solution. For example, if the polymer produced in the reaction solution and the catalyst are compatible, the catalyst can reach the interior of the produced polymer with high efficiency and act on the internal reactive groups, which can cause a certain degree of decomposition of the produced polymer itself. However, in the present invention, since the polymer produced in the reaction solution and the catalyst are incompatible, the catalyst selectively acts on the terminal groups of the polymer, thereby suppressing the decomposition reaction of the polymer produced in the reaction solution.

[0029] <Raw Materials> In the production method of the present invention, a raw material containing a carbonyl compound (carbonate ester compound) represented by the following general formula (1) (this raw material will be referred to as "raw material (I)") is used as a synthetic raw material (monomer or prepolymer) for a polycarbonate compound. Raw material (I) can contain one or more types of carbonyl compounds represented by the following general formula (1). Furthermore, as will be described in detail later, raw material (I) can contain a reactive group (R １ and R ２ Depending on the type of the carbonyl compound, a synthetic raw material (a polyvalent hydroxy compound) other than the carbonyl compound represented by the following general formula (1) may be contained.

[0030]

[0031] In general formula (1), R １ represents an alkyl group or a cycloalkyl group. ２ represents a hydrogen atom, an alkoxycarbonyl group, or a cycloalkoxycarbonyl group. L represents a divalent organic group. n is an integer of 1 or more.

[0032] R １The alkyl group that can be used as R may be linear or branched. From the viewpoint of being able to efficiently remove hydroxy compounds (alcohols, etc.) that are by-products in the polymerization reaction at lower temperatures, it is preferable that the number of carbon atoms in this alkyl group is short. １ The number of carbon atoms in the alkyl group that can be taken as R is preferably 1 to 10, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3. １ Specific preferred examples of the alkyl group that can be taken include methyl, ethyl, propyl and butyl, more preferably ethyl or methyl, and particularly preferably methyl.

[0033] R １ The cycloalkyl group that can be taken as R preferably has 3 to 10 ring members, more preferably 3 to 7, even more preferably 3 to 6, and even more preferably 3 or 4. From the viewpoint of being able to efficiently remove hydroxy compounds (alcohols, etc.) that are by-products in the polymerization reaction at lower temperatures, R １ The cycloalkyl group which can be taken as is more preferably cyclopropyl.

[0034] R ２ The alkyl group constituting the alkoxycarbonyl group can be in the form of R １ The alkyl groups are the same as those that can be taken as R, and the preferred forms are also the same. ２ The form of the cycloalkyl group constituting the cycloalkoxycarbonyl group that can be taken as R １ The preferred forms are the same as those of the cycloalkyl group that can be taken as above.

[0035] The divalent organic group that can be used as L is not particularly limited and can be appropriately designed depending on the target polycarbonate compound. Furthermore, the structure of L can be appropriately designed in consideration of allowing the metal salt catalyst to exist in a solid state without dissolving (to make the carbonyl compound represented by general formula (1) and the metal salt catalyst incompatible with each other). The chemical formula weight of the divalent organic group that can be used as L is typically 50 to 2,000, preferably 80 to 1,000. L may have a chain structure or a cyclic structure. When L has a cyclic structure, this ring may be an aliphatic ring or an aromatic ring. From the viewpoint of increasing the refractive index and improving the durability of the polymer, it is preferable that L have an aromatic ring. Specific preferred examples of the divalent organic group that can be used as L are shown below, but the present invention is not limited to these examples except as specified in the present invention. * indicates a bond.

[0036]

[0037] In general formula (1), n, which indicates the number of repeating units, is not particularly limited as long as it is 1 or more, and is preferably 1 to 20, more preferably 1 to 15, even more preferably 1 to 10, still more preferably 1 to 8, also preferably 1 to 6, and may be 1 to 4.

[0038] R of the carbonyl compound represented by general formula (1) contained in the raw material (I) ２ When R is a hydrogen atom, R １ and R ２ A reaction occurs between R and R, and a polycarbonate compound is produced by step-growth polymerization. Therefore, it is not essential to add raw materials other than the carbonyl compound represented by general formula (1) in producing the polycarbonate compound. ２ The carbonyl compound represented by the general formula (1) in which is a hydrogen atom is used as a raw material, and the desired polycarbonate compound can be obtained without using any other raw materials.

[0039] On the other hand, if R ２ In the case where the carbonyl compound represented by the general formula (1) in which R is a hydrogen atom is contained, the raw material (I) may contain R ２In this case, the carbonyl compound represented by the general formula (1) and / or the polyvalent hydroxy compound (typically a diol compound) may be contained. ２ The structure of the carbonyl compound represented by general formula (1) in which R is not a hydrogen atom is not particularly limited and can be appropriately designed depending on the purpose. ２ is not a hydrogen atom, is contained in the same raw material (I), ２ The polyhydroxy compound may or may not have the same structural moiety as L in the carbonyl compound represented by general formula (1) in which R is a hydrogen atom. Similarly, the structure of the polyhydroxy compound is not particularly limited and can be appropriately designed depending on the purpose. For example, the polyhydroxy compound may be a compound having R ２ The carbonyl compound represented by the general formula (1) may or may not have the same structural unit as L in the carbonyl compound represented by the general formula (1) in which R is a hydrogen atom. ２ may or may not have the same structural moiety as L in the carbonyl compound represented by general formula (1) in which L is not a hydrogen atom.

[0040] From another perspective, R of the carbonyl compound represented by general formula (1) contained in the raw material (I) ２ is not a hydrogen atom, R １ and R ２ Therefore, in this case, the raw material (I) does not contain R ２ In addition to the carbonyl compounds represented by general formula (1) in which R ２ is a hydrogen atom, and / or a polyvalent hydroxy compound (typically a diol compound). ２ The structure of the carbonyl compound represented by general formula (1) in which R is a hydrogen atom is not particularly limited and can be appropriately designed depending on the purpose. ２ is a hydrogen atom, is contained in the same raw material (I), ２is not a hydrogen atom. Similarly, the structure of the polyvalent hydroxy compound is not particularly limited and can be appropriately designed depending on the purpose. For example, when the polyvalent hydroxy compound is a carbonyl compound having R ２ In addition, the polyvalent hydroxy compound may or may not have the same structural unit as L in the carbonyl compound represented by general formula (1) in which R is not a hydrogen atom. ２ may or may not have the same structural moiety as L in the carbonyl compound represented by general formula (1) in which is a hydrogen atom.

[0041] In short, raw material (I) contains one or more types of monomers or prepolymers that undergo a polymerization reaction in the presence of the metal salt catalyst to produce the target polycarbonate compound, and at least one of these is a carbonyl compound represented by the general formula (1).

[0042] In the above-described embodiment, raw material (I) contains R ２ In addition, the raw material (I) may contain one or more carbonyl compounds represented by the general formula (1) in which R is a hydrogen atom. ２ is not a hydrogen atom, one or more types of carbonyl compounds represented by general formula (1) can be used. Similarly, one or more types of polyvalent hydroxy compounds can be used in raw material (I). An example of a combination (raw material mixture) of each raw material (monomer or prepolymer) contained in raw material (I) is shown below. The raw material mixture shown below consists of six types of raw materials, and (I-b), (I-c), (I-e), and (If) correspond to carbonyl compounds represented by general formula (1) above (L in general formula (1) above is an organic group containing a diphenylfluorene skeleton). Me represents methyl.

[0043]

[0044] The polycarbonate compound obtained by the production method of the present invention may be a linear polymer, or may have a branched or crosslinked structure, but is preferably a linear polymer. The polycarbonate compound obtained by the production method of the present invention preferably has a weight average molecular weight (Mw) of more than 10,000, more preferably 12,000 or more, even more preferably 15,000 or more, even more preferably 18,000 or more, and even more preferably 20,000 or more. A more preferred range for Mw is 18,000 to 1,000,000, more preferably 20,000 to 500,000, even preferably 20,000 to 300,000, even preferably 23,000 to 200,000, and even preferably 25,000 to 100,000. In the present invention, Mw is determined under the following measurement conditions. Apparatus: HLC-8420GPC (manufactured by Tosoh Corporation) Detector: Differential refractometer (RI (Refractive Index) detector) Precolumn: TSKGELGUARDCOLUMN SUPERMP(HZ)-M 4.6 mm x 20 mm (manufactured by Tosoh Corporation) Column: Two directly connected columns: TSKGEL SUPERMULTIPOREHZ-M 4.6 mm x 150 mm (manufactured by Tosoh Corporation) Thermostat temperature: 40°C Mobile phase: THF Mobile phase flow rate: 0.6 mL / min Sample concentration: 0.1% by mass Sample injection volume: 10 μL Data collection time: 5 to 15 minutes after sample injection Sampling pitch: 500 msec

[0045] <Polymerization Reaction> In the production method of the present invention, the polymerization reaction of the raw materials (monomers or prepolymers) can be carried out by a conventional method for obtaining a polycarbonate compound, except that the metal salt catalyst is present in a solid state in the reaction system. Preferred reaction conditions will be described in the order of a batch system and a flow system, but the present invention is not limited to the following reaction conditions except as specified in the present invention.

[0046] -Batch Method- In a batch reaction, the total amount of raw materials (the carbonyl compound represented by general formula (1) and the polyvalent hydroxy compound used as needed) used in the reaction can be set appropriately. For example, the total content of the raw materials in the reaction solution is preferably 0.1 to 100% by mass, more preferably 5 to 95% by mass, and even more preferably 10 to 90% by mass. The quantitative ratio of raw materials to metal salt catalyst in the reaction solution is not particularly limited and can be set appropriately. For example, the mass ratio of raw materials (total amount of raw materials used in the reaction) / metal salt catalyst can be 1,000,000 / 1 to 0.1 / 1, preferably raw materials / metal salt catalyst = 500,000 / 1 to 2 / 1, and also preferably raw materials / metal salt catalyst = 200,000 / 1 to 4 / 1. Furthermore, it is also preferable that the raw material / metal salt catalyst ratio be 100,000 / 1 to 6 / 1, it is also preferable that the raw material / metal salt catalyst ratio be 10,000 / 1 to 8 / 1, it is also preferable that the raw material / metal salt catalyst ratio be 1,000 / 1 to 10 / 1, and it is also preferable that the raw material / metal salt catalyst ratio be 200 / 1 to 20 / 1.

[0047] The reaction temperature is preferably 60 to 350°C, more preferably 100 to 300°C, and even more preferably 130 to 260°C. This polymerization reaction is preferably carried out under reduced pressure from the viewpoint of removing by-products such as methanol and dialkyl carbonate. For example, the pressure of the reaction system can be set to 1 to 40,000 Pa, and more preferably 3 to 5,000 Pa.

[0048] The reaction time is not particularly limited as long as a polycarbonate compound having the desired molecular weight is obtained, and can be, for example, 1 minute to 10 hours, more preferably 3 minutes to 6 hours, and even more preferably 5 minutes to 3 hours.

[0049] The polymerization reaction may be carried out without a solvent, or a solvent may be used. When a solvent is used, it is preferable to use a solvent that can dissolve the carbonyl compound product but does not dissolve the metal salt catalyst or has low solubility for the metal salt catalyst. The solvent is usually an organic solvent. Examples of such solvents include halogen-containing solvents, ether solvents having a linear, branched, or cyclic structure, and hydrocarbon solvents. Examples of halogen-containing solvents include methylene chloride, chloroform, dichloroethane, carbon tetrachloride, chlorobenzene, and o-dichlorobenzene. Examples of ether solvents include tetrahydrofuran, dioxane, methyl tertiary butyl ether, cyclopentyl methyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, triglyme, tetraglyme, methyl cellosolve acetate, and derivatives thereof. Examples of hydrocarbon solvents include hexane, heptane, octane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, mesitylene, decalin, tetralin, and derivatives thereof. Further, as the solvent, ketone-based solvents such as acetone, methyl ethyl ketone, diisobutyl ketone, cyclohexanone, and methyl isobutyl ketone, nitrile-based solvents such as acetonitrile, lactone-based solvents such as γ-butyrolactone, ester-based solvents such as ethyl acetate and butyl acetate, and amide-based solvents such as dimethylacetamide, dimethylformamide, N-methylpyrrolidone, tetramethylurea, and dimethylimidazolidinone can also be used. One of the above solvents may be used alone, or two or more of them may be used as a mixed solvent.

[0050] -Flow Method- In a preferred embodiment of the flow reaction, the insolubilized metal salt catalyst (preferably a metal salt catalyst having a polymeric inorganic compound or an organic polymer structure) is packed into a column, and a liquid containing the raw materials is circulated through the column, whereby the polymerization reaction of the raw materials proceeds while flowing through the column. The target polycarbonate compound can be obtained by controlling the time the raw materials pass through the column. The time the raw materials pass through the column can be controlled by the column length, flow rate, etc. The time the raw materials pass through the column can be, for example, 10 seconds to 3 hours, and preferably 30 seconds to 1 hour. For example, a solution obtained by dissolving the raw materials in the organic solvent can be circulated through the column as the liquid containing the raw materials. The column temperature is, for example, preferably 60 to 350°C, more preferably 100 to 300°C, and even more preferably 130 to 260°C.

[0051] The present invention will be described in more detail based on examples, but the present invention should not be construed as being limited to these examples except as defined in the present invention.

[0052] Example 1 Preparation of Raw Materials A 50 mL recovery flask was charged with 1.2 g of a quaternary ammonium salt (anion exchange resin, trade name: Amberlite 900Cl, manufactured by Aldrich) as a catalyst, 3.0 g of a diol compound having the following structure, and 6 g of dimethyl carbonate, and the mixture was stirred under reflux in the atmosphere at 150°C for 2 hours. The reaction solution was cooled to room temperature, the catalyst was removed by filtration, and carbonyl compound A-1 having the following structure was separated and recovered by liquid chromatography and used as a raw material.

[0053]

[0054] <Preparation of Metal Salt Catalyst> 1 g of crosslinked polymethacrylic acid (cation exchange resin, product name: Amberlite CG50, manufactured by Organo Corporation) having the anionic structure shown below in X-1 was mixed with 50 g of a 2 M magnesium acetate solution (solvent: water), and the crosslinked polymethacrylic acid was immersed in the 2 M magnesium acetate solution and allowed to stand for 24 hours. The mixture was then filtered, and the residue was washed with methanol and dried to obtain crosslinked magnesium polymethacrylate, a metal salt catalyst.

[0055] <Polymerization Reaction> 0.40 g of the carbonyl compound A-1 and 14.5 mg of the crosslinked magnesium polymethacrylate were placed in a 20 mL Schlenk flask, and the mixture was stirred under reduced pressure (5 Torr, 667 Pa) at 200°C for 1 hour to carry out a polymerization reaction. During this time, the crosslinked magnesium polymethacrylate was present in a solid state without dissolving in the reaction solution. The reaction solution was cooled to room temperature, and the resulting polycarbonate was analyzed by gel permeation chromatography, revealing that it had an Mw of 38,000.

[0056] The color of the resulting reaction solution was visually evaluated based on the Hazen color scale (APHA). The evaluation criteria for color are as follows: A: 0 to 50 B: 51 to 100 C: 101 to 200 D: 201 or higher

[0057] The state of the metal salt catalyst in the polymerization reaction system was visually observed and evaluated according to the following criteria. The following states A and B indicate that the reaction liquid was a suspension (slurry) and the metal salt catalyst was present in a solid state in the polymerization reaction system. A: The catalyst was present in a solid state without dissolving in the reaction system. B: The catalyst was present in a solid state in the reaction system, but some of it was dissolved. C: The catalyst was dissolved in the reaction system and no solid matter could be observed.

[0058] Examples 2 to 42, Comparative Examples 1 to 11 Polymerization reactions were carried out in the same manner as in Example 1, except that carbonyl compound A-1 was replaced with the carbonyl compound shown in the table below, and the organic anion of the metal salt catalyst (anion of crosslinked polymethacrylic acid) was replaced with the organic anion shown in the table below. Note that X-3 in Example 3 and X-13 in Example 13 are both polymer compounds having a coordination atom rather than an anion, but are listed in the "anion" column for convenience. The metal salt catalyst in Example 3 was magnesium acetate (magnesium salt of X-29) in which X-3 was coordinated to the magnesium, and the metal salt catalyst in Example 13 was magnesium acetate in which X-13 was coordinated to the magnesium. The molecular weight and color of the resulting polycarbonate were determined in the same manner as in Example 1.

[0059] The results of the above Examples and Comparative Examples are summarized in the table below. The carbonyl compounds used and the anion structures of the metal salt catalysts are also shown below the table. Me stands for methyl, Et stands for ethyl, ｎ Bu is n-butyl, ｎ Pr is n-propyl. m, n, and r are molar ratios. X-13 and X-14 represent structures in which the silanol groups of silica are chemically modified. X-15 represents the anionic structure of zeolite (SiO ４ Tetrahedron and AlO ４ It represents a structure in which tetrahedra are connected three-dimensionally via oxygen atoms.

[0060]

[0061]

[0062]

[0063]

[0064] As is clear from the results in the above table, when the metal salt catalyst was dissolved in the polymerization reaction system and the reaction liquid was in a solution state, the Mw of the resulting polycarbonate was within the range of 1,000 to 8,000, and the degree of polymerization was low (Comparative Examples 1 to 11). In contrast, when the metal salt catalyst was present in a solid state in the polymerization reaction system, the molecular weight of the resulting polycarbonate could be significantly increased (Examples 1 to 42). Thus, it was demonstrated that by having the metal salt catalyst present in a solid state in the polymerization reaction system to an extent that it can be clearly distinguished visually (by making the reaction system a slurry), the polymerization activity of the catalyst can be effectively increased. Furthermore, it can be seen that coloration can also be effectively prevented.

[0065] While the present invention has been described in connection with embodiments thereof, we do not intend to limit our invention to any of the details of the description unless otherwise specified, and believe that the claims should be construed broadly without departing from the spirit and scope of the invention as set forth in the appended claims.

[0066] This application claims priority based on Japanese Patent Application No. 2024-043808, filed on March 19, 2024, the contents of which are incorporated herein by reference as part of the present specification.

Claims

1. A method for producing a polycarbonate compound, comprising polymerizing a raw material containing a carbonyl compound represented by the following general formula (1) in the presence of a metal salt catalyst, and causing the metal salt catalyst to be present in a solid state in a reaction system of the polymerization reaction: In general formula (1), R １ represents an alkyl group or a cycloalkyl group. ２ represents a hydrogen atom, an alkoxycarbonyl group, or a cycloalkoxycarbonyl group. L represents a divalent organic group. n is an integer of 1 or more.

2. The method for producing a polycarbonate compound according to claim 1, wherein the metal cation constituting the metal salt catalyst is selected from the group consisting of magnesium ions, sodium ions, potassium ions, cesium ions, calcium ions, aluminum ions and lithium ions.

3. The method for producing a polycarbonate compound according to claim 2, wherein the metal cation constituting the metal salt catalyst is a magnesium ion.

4. The method for producing a polycarbonate compound according to any one of claims 1 to 3, wherein the metal salt catalyst is a metal salt of an organic anion.

5. The method for producing a polycarbonate compound according to claim 4, wherein the organic anion has 3 or more carbon atoms.

6. The method for producing a polycarbonate compound according to claim 5, wherein the anion moiety of the organic anion is selected from the group consisting of a carboxylate anion, a sulfonate anion, a phosphate anion, a phosphonate anion and a sulfinyl anion.

7. The method for producing a polycarbonate compound according to claim 6, wherein the organic anion has 5 or more carbon atoms and the anion portion of the organic anion is a carboxylate anion.

8. The method for producing a polycarbonate compound according to claim 7, wherein the organic anion has a branched structure.

9. The method for producing a polycarbonate compound according to any one of claims 1 to 3, wherein the metal salt catalyst has an organic polymer structure.

10. The method for producing a polycarbonate compound according to claim 9, wherein the organic polymer structure has a crosslinked structure.

11. The method for producing a polycarbonate compound according to claim 10, wherein the metal salt catalyst is a metal salt formed by ionic bonding between an organic polymer anion and a metal cation.

12. The method for producing a polycarbonate compound according to claim 11, wherein the anion portion of the organic polymer anion is a carboxylate anion.

13. In the general formula (1), R １ The method for producing a polycarbonate compound according to any one of claims 1 to 3, wherein is methyl, ethyl, propyl, or butyl.

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