Immobilized zinc complex having guanidine ligand, method for producing same, and method for producing cyclic carbonate using same

Abstract

Provided is an immobilized zinc complex comprising at least: a compound represented by general formula (1) (where R1 and R2 each represent a monovalent hydrocarbon group, R3 represents a divalent hydrocarbon group, R4 to R7 each represent a hydrogen atom or monovalent hydrocarbon group, R4 and R5, R6 and R7, or R4 and R6 may be combined with each other to form a ring, and n represents an integer of 0-2); a zinc halide represented by general formula (2) ZnX2 (where X represents a halogen atom); and an inorganic carrier, wherein silicon atoms, in the zinc complex having a guanidine ligand, in which a nitrogen atom in the compound represented by general formula (1) and a zinc atom in the zinc halide are bonded via a coordinate bond, are immobilized via covalent bonds with oxygen atoms on the surface of the inorganic carrier. The immobilized zinc complex can provide a cyclic carbonate compound at a good yield under mild conditions such as ambient pressure and / or room temperature conditions, and can be easily recovered and reused after the reaction.

Description

[Technical Field]

[0001] The present invention relates to an immobilized zinc complex having a guanidine ligand, a method for producing the same, and a method for producing a cyclic carbonate using the same. [Background technology]

[0002] Cyclic carbonate compounds, typified by ethylene carbonate and propylene carbonate, have excellent properties such as high dielectric constant, ease of derivatization, and low toxicity, and are therefore useful, for example, as electrolyte solvents for lithium secondary batteries, raw materials for plastics such as polycarbonate and polyhydroxyurethane, and resin plasticizers.

[0003] One method for producing cyclic carbonate compounds is the cycloaddition reaction of epoxides with carbon dioxide in the presence of a catalyst. This method can fix carbon dioxide and convert it into useful compounds, making it an important way to utilize carbon dioxide from the perspective of carbon neutrality, which is a strong social demand. In the cycloaddition reaction of the above-mentioned epoxide with carbon dioxide, homogeneous catalysts such as quaternary ammonium salts and alkali metal salts have conventionally been used as catalysts.

[0004] On the other hand, immobilized catalysts are useful because they offer advantages not available with homogeneous catalysts, such as easy separation from the product by filtration or other methods, the ability to recover and reuse, and the applicability to continuous synthesis. Specifically, the use of immobilized catalysts simplifies the catalyst removal process, improves productivity and atomic efficiency, and reduces waste products such as solvents used in the reaction and cleaning, and catalyst residues. Because of these advantages, the use of immobilized catalysts has been actively investigated in recent years, even in the cycloaddition reaction of epoxides with carbon dioxide.

[0005] A pioneering example of an immobilized catalyst is a phosphonium bromide salt catalyst immobilized on silica gel. For example, in Patent Document 1, a cyclic carbonate compound is produced from epoxide and carbon dioxide under conditions of 10 atmospheres and 90°C using an alkyltriarylphosphonium bromide salt immobilized on silica gel as a catalyst. The catalyst in Patent Document 1 can be easily recovered by filtration after the reaction is completed and can be reused without significant loss of catalytic activity. In addition, in Patent Document 2, propylene carbonate and ethylene carbonate are continuously produced by supplying an epoxide and carbon dioxide to a reactor filled with the catalyst under conditions of 70 atmospheres and 100°C using a tetraalkylphosphonium bromide salt immobilized on silica gel as a catalyst. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-296066 [Patent Document 2] International Publication No. 2015 / 008854 Summary of the Invention [Problem to be solved by the invention]

[0007] By using a phosphonium bromide salt catalyst immobilized on silica gel, efficiency has been improved by taking advantage of the advantages of the immobilized catalyst. However, these methods have the drawback of requiring harsh reaction conditions. For example, in the case of the immobilized catalysts of Patent Documents 1 and 2, due to their low catalytic activity, high-pressure and high-temperature reactions of 10 atmospheres and 90°C or 70 atmospheres and 100°C are required to produce cyclic carbonate compounds in high yields. As described above, methods requiring high-pressure and high-temperature reaction conditions not only require the use of a large excess of carbon dioxide, but also incur significant energy costs due to heating, posing a challenge from the perspective of sustainable production. In addition, in Patent Document 2, the catalyst is prone to deactivation during the reaction, and to prevent this, it is necessary to separately add an alkyl bromide such as 2-bromoethanol, which is undesirable from the perspective of atom efficiency.

[0008] Therefore, when producing a cyclic carbonate compound from an epoxide and carbon dioxide, there is a strong demand for the development of a highly active immobilized catalyst that can smoothly promote the reaction under mild reaction conditions, such as atmospheric pressure and / or room temperature, without the addition of additives.

[0009] The present invention has been made in view of the above circumstances, and aims to provide a zinc complex having a guanidine ligand immobilized on an inorganic support, which can produce a cyclic carbonate compound in good yield under mild conditions such as atmospheric pressure and / or room temperature, and which can be easily recovered and reused after the reaction, a method for producing the same, and a method for producing a cyclic carbonate compound using the immobilized zinc complex. [Means for solving the problem]

[0010] As a result of intensive research to solve the above-mentioned problems, the present inventors have found that by using an immobilized zinc complex having a guanidine ligand as a catalyst in the cycloaddition reaction of an epoxide with carbon dioxide, the corresponding cyclic carbonate compound can be produced in high yield and high purity under mild reaction conditions such as atmospheric pressure (0.09 to 0.11 MPa) and / or room temperature (1 to 30°C), and that the immobilized zinc complex catalyst can be easily recovered and reused after completion of the reaction, thereby completing the present invention.

[0011] That is, the present invention is 1. The following general formula (1) [ka] (In the formula, R 1 and R 2 each independently represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and R 3 represents an unsubstituted divalent hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom, and R 4 ~R 7 are each independently a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and R 4 and R 5 , R 6 and R 7 and R 4 and R 6 may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded, and n represents an integer of 0 to 2. a guanidine-containing alkoxysilane compound represented by the following general formula (2): ZnX2(2) (In the formula, X represents a halogen atom.) and an inorganic carrier, an immobilized zinc complex having a guanidine ligand, in which a nitrogen atom of a guanidine-derived moiety of the guanidine-containing alkoxysilane compound and a zinc atom of the zinc halide are bonded via a coordinate bond, and a silicon atom of the zinc complex is immobilized on an inorganic carrier via a covalent bond with an oxygen atom on the surface of the inorganic carrier; 2. The following general formula (1) [ka] (In the formula, R 1 ~R 7 and n have the same meaning as above. and a guanidine-containing alkoxysilane compound represented by the following general formula (2): ZnX2(2) (In the formula, X has the same meaning as above.) to form a zinc complex having a guanidine ligand by bonding a nitrogen atom of the guanidine moiety of the guanidine-containing alkoxysilane compound to a zinc atom of the zinc halide via a coordinate bond, and then to mix the resulting zinc complex having a guanidine ligand with an inorganic support to form a covalent bond between a silicon atom of the zinc complex having a guanidine ligand and an oxygen atom on the surface of the inorganic support, thereby immobilizing the zinc complex on the inorganic support. 3. The following general formula (1) [ka] (In the formula, R 1 ~R 7 and n have the same meaning as above. and an inorganic carrier to form a covalent bond between an oxygen atom present on the surface of the inorganic carrier and a silicon atom of the guanidine-containing alkoxysilane compound, and to immobilize the guanidine-containing alkoxysilane compound on the inorganic carrier to obtain an organic-inorganic composite material. Then, the organic-inorganic composite material is mixed with a compound represented by the following general formula (2): ZnX2(2) (In the formula, X has the same meaning as above.) and bonding a nitrogen atom of a guanidine moiety contained in the organic-inorganic composite material to a zinc atom of the zinc halide via a coordinate bond to obtain a zinc complex having a guanidine ligand. 4. The following general formula (3) [ka] [In the formula, R represents a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group having 1 to 18 carbon atoms which may contain a heteroatom, a group represented by the following general formula (4), or a group represented by the following general formula (5). [ka] (In the formula, R 8 represents an unsubstituted divalent hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom, and R 9 and R 10 each independently represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and m represents an integer of 0 to 3. [ka] (In the formula, R 11 represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 20 carbon atoms, which may contain a heteroatom.)] and carbon dioxide in the presence of a catalyst, and a cycloaddition reaction is carried out on the epoxide represented by the following general formula (6): [ka] [In the formula, R' represents a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group having 1 to 18 carbon atoms which may contain a heteroatom, a group represented by the following general formula (4), or a group represented by the following general formula (7). [ka] (In the formula, R 8 ~R 10 and m have the same meaning as above. [ka] (In the formula, R 11 represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 20 carbon atoms, which may contain a heteroatom. In a method for producing a cyclic carbonate compound represented by the following formula: A method for producing a cyclic carbonate compound using an immobilized zinc complex having a guanidine ligand as the catalyst. to provide. [Effects of the Invention]

[0012] According to the present invention, an immobilized zinc complex having a guanidine ligand can be obtained. Furthermore, when this immobilized zinc complex having a guanidine ligand is used as a catalyst, a cyclic carbonate compound can be produced in high yield and high purity under mild conditions, such as atmospheric pressure and / or room temperature. Furthermore, the zinc complex having a guanidine ligand immobilized on an inorganic support used as a catalyst can be easily recovered and reused after the reaction is completed. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is an IR spectrum of the immobilized zinc bromide complex having an N′,N′,N″,N″-tetramethylguanidine ligand obtained in Example 1-1. [Figure 2] 1 is an IR spectrum of N-[3-(trimethoxysilyl)propyl]-N',N',N'',N''-tetramethylguanidine, which is a raw material in Example 1-1. [Figure 3] 1H-NMR spectrum of 4,4'-[(2,2-dimethyl-1,3-propanediyl)bis(oxymethylene)]bis(1,3-dioxolan-2-one) obtained in Example 2-6. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention will be specifically described below. The immobilized zinc complex having a guanidine ligand according to the present invention is composed of at least a guanidine-containing alkoxysilane compound (hereinafter referred to as "compound (1)") represented by the following general formula (1), a zinc halide (hereinafter referred to as "compound (2)") represented by the following general formula (2), and an inorganic support, and has a guanidine ligand in which the nitrogen atom of the guanidine moiety of compound (1) and the zinc atom of compound (2) are bound via a coordinate bond, and the silicon atom of the zinc complex is immobilized to the inorganic support via a covalent bond with an oxygen atom on the surface of the inorganic support.

[0015] [ka]

[0016] ZnX2(2)

[0017] In the above general formula (1), R 1 and R 2 each independently represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, and more preferably 1 to 3 carbon atoms. R 1 and R 2 The monovalent hydrocarbon group may be linear, branched, or cyclic, and specific examples thereof include linear alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; branched alkyl groups such as isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, isohexyl, isoheptyl, isooctyl, and tert-octyl; cyclic alkyl groups such as cyclopentyl and cyclohexyl; alkenyl groups such as vinyl, allyl, 1-propenyl, butenyl, and methallyl (2-methyl-2-propenyl); aryl groups such as phenyl, tolyl, and xylyl; and aralkyl groups such as benzyl and phenethyl.

[0018] Among these, R 1 and R 2As the group, a substituted or unsubstituted linear, branched or cyclic alkyl group, alkenyl group, aryl group or aralkyl group having 1 to 5 carbon atoms is preferred, and from the viewpoint of easy availability of raw materials in particular, an unsubstituted linear alkyl group having 1 to 3 carbon atoms is more preferred, and a methyl group or an ethyl group is even more preferred. Some or all of the hydrogen atoms of these monovalent hydrocarbon groups may be substituted with other substituents, such as alkoxy groups having 1 to 3 carbon atoms, such as methoxy, ethoxy, and propoxy; halogen atoms, such as fluorine, chlorine, and bromine; aryl groups having 6 to 10 carbon atoms, such as phenyl and tolyl; aralkyl groups having 7 to 10 carbon atoms, such as benzyl and phenethyl; cyano, amino, ester, ether, carbonyl, acyl, and sulfide groups, and one or more of these may be used in combination. There are no particular limitations on the substitution positions of these substituents, and there are no limitations on the number of substituents.

[0019] In the above general formula (1), R 3 represents an unsubstituted divalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 9 carbon atoms, more preferably 1 to 8 carbon atoms, even more preferably 1 to 5 carbon atoms, and still more preferably 1 to 3 carbon atoms, which may contain a heteroatom. R 3 The divalent hydrocarbon group may be linear, branched, or cyclic, and specific examples thereof include alkylene groups such as methylene, ethylene, trimethylene, tetramethylene, isobutylene, hexamethylene, octamethylene, decamethylene, cyclohexylene, and methylenecyclohexylene; alkenylene groups such as butynylene, propenylene, butenylene, hexenylene, and octenylene; arylene groups such as phenylene; and aralkylene groups such as methylenephenylene and methylenephenylenemethylene. Among these, R 3 As the alkylene group, an unsubstituted linear alkylene group having 1 to 8 carbon atoms is preferable, and from the viewpoint of easy availability of raw materials in particular, a methylene group, a trimethylene group, or an octamethylene group is more preferable, and from the viewpoint of catalytic activity, a methylene group or a trimethylene group is even more preferable, and a methylene group is even more preferable. These divalent hydrocarbon groups may have one or more heteroatoms such as ether groups, carbonyl groups, amino groups, sulfide groups, etc., present in the molecular chain.

[0020] In the above general formula (1), R 4 ~R 7 are each independently a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 7 carbon atoms, more preferably 1 to 5 carbon atoms, and even more preferably 1 to 3 carbon atoms. R 4 ~R 7 The monovalent hydrocarbon group may be linear, branched, or cyclic, and specific examples thereof include linear alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; branched alkyl groups such as isopropyl, isobutyl, sec-butyl, tert-butyl, thexyl (1,1,2-trimethylpropyl), and 2-ethylhexyl; cyclic alkyl groups such as cyclopentyl and cyclohexyl; alkenyl groups such as vinyl, allyl, and 1-propenyl; aryl groups such as phenyl and tolyl; and aralkyl groups such as benzyl. Of these, from the viewpoint of easy availability of raw materials, methyl, ethyl, isopropyl, cyclohexyl, phenyl, and benzyl are preferred. Also, R 4 and R 5 , R 6 and R 7 and R 4 and R 6 may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded. When a ring is formed, the number of carbon atoms contained in the ring is preferably 3 to 10, preferably 3 to 8, and more preferably 3 to 6. Examples of such ring structures include a piperidine ring, a pyrrolidine ring, a piperazine ring, a methylpiperazine ring, a tetramethylpiperidine ring, a morpholine ring, an imidazolidine ring, and a tetrahydropyrimidine ring.

[0021] Specific examples of compound (1) include N-(alkoxysilyl)alkylguanidines such as N-[3-(trimethoxysilyl)propyl]guanidine, N-[3-(dimethoxymethylsilyl)propyl]guanidine, N-[3-(methoxydimethylsilyl)propyl]guanidine, N-[3-(triethoxysilyl)propyl]guanidine, N-[3-(diethoxymethylsilyl)propyl]guanidine, and N-[3-(ethoxydimethylsilyl)propyl]guanidine; N-[3-(trimethoxysilyl)propyl]-N'-methylguanidine, N-[3-(dimethoxymethylsilyl)propyl]-N'-methylguanidine, N-[3-(methoxydimethylsilyl)propyl]-N'-methylguanidine, N-[3-(triethoxysilyl)propyl]-N'-methylguanidine, and N-[3-(diethoxymethylsilyl)propyl]-N'-methylguanidine. N-(alkoxysilyl)alkyl-N'-alkylguanidines such as guanidine, N-[3-(ethoxydimethylsilyl)propyl]-N'-methylguanidine, and N-[3-(trimethoxysilyl)propyl]-N'-benzylguanidine; N-[3-(trimethoxysilyl)propyl]-N',N'-dimethylguanidine, N-[3-(dimethoxymethylsilyl)propyl]-N',N'-dimethylguanidine, N-[ N-(alkoxysilyl)alkyl-N',N'-dialkylguanidines such as [3-(methoxydimethylsilyl)propyl]-N',N'-dimethylguanidine, N-[3-(triethoxysilyl)propyl]-N',N'-dimethylguanidine, N-[3-(diethoxymethylsilyl)propyl]-N',N'-dimethylguanidine, and N-[3-(ethoxydimethylsilyl)propyl]-N',N'-dimethylguanidine;N-[3-(trimethoxysilyl)propyl]-N',N''-dimethylguanidine, N-[3-(dimethoxymethylsilyl)propyl]-N',N''-dimethylguanidine, N-[3-(methoxydimethylsilyl)propyl]-N',N''-dimethylguanidine, N-[3-(triethoxysilyl)propyl]-N',N''-dimethylguanidine, N-[3-(diethoxymethylsilyl)propyl]-N',N''-dimethylguanidine, N-[3-(ethoxydimethylsilyl)propyl]-N',N''-dimethylguanidine, N-[3-(trimethoxysilyl)propyl]-N',N''-diethylguanidine, N-[3-(trimethoxysilyl)propyl]-N',N''-diisopropylguanidine, N-[3-(trimethoxysilyl)propyl]-N',N''-dicyclo N-(alkoxysilyl)alkyl-N',N''-dialkylguanidines such as hexylguanidine; N-(alkoxysilyl)alkyl-N',N',N''-trialkylguanidines such as N-[3-(trimethoxysilyl)propyl]-N',N',N''-trimethylguanidine, N-[3-(dimethoxymethylsilyl)propyl]-N',N',N''-trimethylguanidine, N-[3-(methoxydimethylsilyl)propyl]-N',N',N''-trimethylguanidine, N-[3-(triethoxysilyl)propyl]-N',N',N''-trimethylguanidine, N-[3-(diethoxymethylsilyl)propyl]-N',N',N''-trimethyl-dimethylguanidine, and N-[3-(ethoxydimethylsilyl)propyl]-N',N',N''-trimethylguanidine;N-[3-(trimethoxysilyl)propyl]-N',N',N'',N''-tetramethylguanidine, N-[3-(dimethoxymethylsilyl)propyl]-N',N',N'',N''-tetramethylguanidine, N-[3-(methoxydimethylsilyl)propyl]-N',N',N'',N''-tetramethylguanidine, N-[3-(triethoxysilyl)propyl]-N',N',N'',N''-tetramethylguanidine, N-[3-(diethoxymethylsilyl)propyl]-N',N',N'',N''-tetramethylguanidine, N-[3-(ethoxydimethylsilyl)propyl]-N',N',N'',N''-tetramethylguanidine N-(alkoxysilyl)alkyl-N',N',N'',N''-tetraalkylguanidines such as N-[3-(trimethoxysilyl)propyl]-N',N''-diphenylguanidine and N-[3-(trimethoxysilyl)propyl]-N'-phenylguanidine; N-(alkoxysilyl)alkylarylguanidines such as N-(1,3-dimethyl-2-imidazolidinylidene)-3-(trimethoxysilyl)-1-propanamine and N-(tetrahydro-1,3-dimethyl-2(1H)-pyrimidinylidene)-3-(trimethoxysilyl)-1-propanamine;

[0022] Among these, from the viewpoint of easy availability of raw materials, N-(alkoxysilyl)alkyl-N',N',N'',N''-tetraalkylguanidine is preferred, and N-[(trialkoxysilyl)propyl]-N',N',N'',N''-tetramethylguanidine and N-[(dialkoxymethylsilyl)propyl]-N',N',N'',N''-tetramethylguanidine are even more preferred. Compound (1) may be commercially available or may be produced according to a conventionally known method, for example, by subjecting a haloalkylsilane compound to a substitution reaction with a guanidine compound.

[0023] In the above general formula (2), X represents a halogen atom such as fluorine, chlorine, bromine, or iodine. Specific examples of compound (2) include zinc fluoride, zinc chloride, zinc bromide, and zinc iodide. From the viewpoint of both easy availability of raw materials and catalytic activity, zinc bromide is particularly preferred. The compound (2) used may be a commercially available product.

[0024] In the immobilized zinc complex of the present invention, the zinc complex having a guanidine ligand refers to a complex in which the nitrogen atom of the guanidine moiety derived from compound (1) and the zinc atom of compound (2) are bound via a coordinate bond. In the present invention, it is preferable that the guanidine moiety derived from compound (1) is coordinately bonded in an amount of preferably 1.0 to 4.0 mol, more preferably 1.0 to 2.0 mol, per mol of zinc atom in compound (2), to form a 4- to 6-coordinate zinc complex.

[0025] The compound coordinated to the zinc atom of the immobilized zinc complex having a guanidine ligand of the present invention is not limited to the guanidine derived from compound (1), and solvent molecules may also be coordinated. Here, examples of the solvent molecules include the reaction solvents described below that are used in producing the zinc complex having a guanidine ligand immobilized on an inorganic support of the present invention.

[0026] The inorganic support used in the present invention may be any material having hydroxyl groups on its surface, such as silica gel, mesoporous silica, alumina, zeolite, titania, ceria, zirconia, or magnetite, and from the viewpoint of availability of raw materials, silica gel, mesoporous silica, alumina, and zeolite are preferred.

[0027] Here, the inorganic support is immobilized via a covalent bond in an amount of preferably 0.5 to 10.0 kilograms (corresponding to 2.0 mmol / g to 0.1 mmol / g), more preferably 0.5 to 2.0 kilograms (corresponding to 2.0 mmol / g to 0.5 mmol / g), relative to 1 mole of silicon atoms of compound (1), from the viewpoint that a higher loading amount results in better catalytic activity.

[0028] Next, a method for producing an immobilized zinc complex having a guanidine ligand will be described. The immobilized zinc complex having a guanidine ligand according to the present invention can be produced by the following two methods. The first method is a method in which compound (1) and compound (2) are mixed in the presence of an organic solvent, if necessary, to form a zinc complex having a guanidine ligand by bonding the nitrogen atom of the guanidine moiety of compound (1) to the zinc atom of the zinc halide via a coordinate bond, and then the resulting zinc complex having a guanidine ligand is mixed with an inorganic support to form a covalent bond between the silicon atom of the zinc complex having a guanidine ligand and the oxygen atom on the surface of the inorganic support, thereby immobilizing the zinc complex on the inorganic support.

[0029] In the step of forming a zinc complex having a guanidine ligand, examples of a solvent that may be used as needed include hydrocarbon solvents such as benzene, toluene, and xylene; ether solvents such as diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 4-methyltetrahydropyran, and dioxane; ester solvents such as ethyl acetate and butyl acetate; aprotic polar solvents such as acetonitrile, N,N-dimethylformamide, and N-methylpyrrolidone; and chlorinated hydrocarbon solvents such as dichloromethane and chloroform. These solvents may be used alone or in combination of two or more. When a solvent is used in the zinc complex formation step, the amount thereof is not particularly limited, but is preferably in the range of 0.1 to 50.0 liters, more preferably 0.5 to 20.0 liters, per mole of compound (2).

[0030] The amount of compound (1) used in the zinc complex formation step is not particularly limited, but is preferably in the range of 1.0 to 4.0 mol, more preferably 1.0 to 2.0 mol, per 1 mol of compound (2) to form a zinc complex with 4 to 6 coordination numbers.

[0031] There is no limitation on the pressure during the reaction, but it is preferable to carry out the reaction at normal pressure. The reaction temperature is not particularly limited, but is preferably 0 to 100°C, more preferably 20 to 80°C, and the reaction time is also not particularly limited, but is preferably 1 to 40 hours, more preferably 1 to 10 hours. The reaction is preferably carried out in an atmosphere of an inert gas such as nitrogen or argon.

[0032] A solvent can also be used in the immobilization step in which a solution of the zinc complex having a guanidine ligand is mixed with an inorganic carrier to form a covalent bond between the silicon atom of the zinc complex having a guanidine ligand and the oxygen atom on the surface of the inorganic carrier, thereby immobilizing the zinc complex on the inorganic carrier. Examples of the solvent include the same solvents as those used in the zinc complex formation step. When a solvent is used in the immobilization step, the amount thereof is not particularly limited, but is preferably in the range of 1.0 to 50.0 liters, more preferably 5.0 to 20.0 liters, per mole of compound (2).

[0033] In the immobilization step, the amount of the inorganic carrier used is not particularly limited, but is preferably in the range of 0.5 to 10.0 kilograms, more preferably 0.5 to 2.0 kilograms, per mole of Compound (1).

[0034] There is no limitation on the pressure in the immobilization step, but it is preferable to carry out the step at normal pressure. The reaction temperature is not particularly limited, but is preferably 20 to 150°C, more preferably 50 to 120°C, and the reaction time is also not particularly limited, but is preferably 1 to 40 hours, more preferably 1 to 10 hours. The reaction is preferably carried out in an atmosphere of an inert gas such as nitrogen or argon.

[0035] A second method for producing an immobilized zinc complex having a guanidine ligand according to the present invention is a method in which compound (1) is mixed with an inorganic support, optionally in the presence of an organic solvent, to form a covalent bond between an oxygen atom present on the surface of the inorganic support and a silicon atom of the guanidine-containing alkoxysilane compound, and the guanidine-containing alkoxysilane compound is immobilized on the inorganic support to obtain an organic-inorganic composite material, and then this organic-inorganic composite material, or a suspension of the organic-inorganic composite material when an organic solvent is used, is mixed with compound (2), to bond the nitrogen atom of the guanidine moiety contained in the organic-inorganic composite material to the zinc atom of compound (2) via a coordinate bond, thereby obtaining a zinc complex having a guanidine ligand.

[0036] Examples of solvents that may be used as needed in the production process of an organic-inorganic composite material include hydrocarbon solvents such as benzene, toluene, and xylene; ether solvents such as diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 4-methyltetrahydropyran, and dioxane; ester solvents such as ethyl acetate and butyl acetate; aprotic polar solvents such as acetonitrile, N,N-dimethylformamide, and N-methylpyrrolidone; and chlorinated hydrocarbon solvents such as dichloromethane and chloroform. These solvents may be used alone or in combination of two or more. When a solvent is used, the amount thereof is not particularly limited, but is preferably in the range of 1.0 to 50.0 liters, more preferably 5.0 to 20.0 liters, per mole of compound (1).

[0037] In the process for producing the organic-inorganic composite material, the amount of inorganic carrier used is not particularly limited, but is preferably in the range of 0.5 to 10.0 kilograms, more preferably 0.5 to 2.0 kilograms, per mole of compound (1).

[0038] There is no limitation on the pressure in the process for producing the organic-inorganic composite material, but it is preferable to carry out the process at normal pressure. The reaction temperature is not particularly limited, but is preferably 20 to 150°C, more preferably 50 to 120°C, and the reaction time is also not particularly limited, but is preferably 1 to 40 hours, more preferably 1 to 10 hours. The reaction is preferably carried out in an atmosphere of an inert gas such as nitrogen or argon.

[0039] A solvent can also be used in the step of forming a zinc complex having a guanidine ligand, and examples of the solvent include the same solvents as those used in the step of producing the organic-inorganic composite material. When a solvent is used, the amount thereof is not particularly limited, but is preferably in the range of 1.0 to 50.0 liters, more preferably 5.0 to 20.0 liters, per mole of compound (2).

[0040] The amount of compound (2) used in the above step is not particularly limited, but is preferably in the range of 0.25 to 1.0 mol, more preferably 0.5 to 1.0 mol, per 1 mol of guanidine derived from compound (1) to form a 4- to 6-coordinate zinc complex.

[0041] In the above process, there is no limitation on the pressure, but it is preferable to carry out the process at normal pressure. The reaction temperature is not particularly limited, but is preferably 0 to 100°C, more preferably 20 to 80°C, and the reaction time is also not particularly limited, but is preferably 1 to 40 hours, more preferably 1 to 10 hours. The reaction is preferably carried out in an atmosphere of an inert gas such as nitrogen or argon.

[0042] The immobilized zinc complex having a guanidine ligand according to the present invention can also be obtained by charging compound (1), compound (2) and an inorganic support all at once and simultaneously carrying out the step of forming the zinc complex having a guanidine ligand and the step of immobilization.

[0043] The immobilized zinc complex having a guanidine ligand obtained by the production method of the present invention can be further purified by a purification method such as filtration, washing, drying under reduced pressure, etc., depending on the desired quality, before use. To obtain a highly pure immobilized zinc complex having a guanidine ligand, purification by filtration, washing, and drying under reduced pressure is particularly preferred.

[0044] Next, a method for producing a cyclic carbonate compound represented by the following general formula (6) (hereinafter referred to as "compound (6)") by using the obtained immobilized zinc complex having a guanidine ligand as a catalyst to carry out a cycloaddition reaction between an epoxide represented by the following general formula (3) (hereinafter referred to as "compound (3)") and carbon dioxide will be described.

[0045] [ka]

[0046] [ka]

[0047] In the above general formula (3), R represents a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms, which may contain a heteroatom, a group represented by the following general formula (4), or a group represented by the following general formula (5).

[0048] [ka]

[0049] In the above general formula (3), the monovalent hydrocarbon group of R may be linear, branched, or cyclic, and specific examples thereof include linear alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, and n-octadecyl groups; isopropyl, isobutyl, Examples include branched alkyl groups such as sec-butyl, tert-butyl, isopentyl, neopentyl, isohexyl, isoheptyl, isooctyl, tert-octyl, isononyl, and isodecyl groups; cyclic alkyl groups such as cyclopentyl and cyclohexyl groups; alkenyl groups such as vinyl, allyl, 1-propenyl, methallyl (2-methyl-2-propenyl), and butenyl groups; aryl groups such as phenyl, tolyl, and xylyl groups; and aralkyl groups such as benzyl and phenethyl groups. Among these, substituted or unsubstituted, linear or branched alkyl groups, alkenyl groups, aryl groups, and aralkyl groups having 1 to 10 carbon atoms are preferred, and from the viewpoint of easy availability of raw materials, alkyl groups having 1 to 6 carbon atoms and aryl groups having 6 to 9 carbon atoms are particularly preferred, with methyl groups, ethyl groups, butyl groups, and phenyl groups being even more preferred.

[0050] Some or all of the hydrogen atoms of these monovalent hydrocarbon groups may be substituted with other substituents, such as R 1 and R 2 The same substituents as those mentioned above can be mentioned. Among these, the other substituents are more preferably an alkoxy group having 1 to 3 carbon atoms, a fluorine atom, a chlorine atom, and a phenyl group, particularly from the viewpoint of easy availability of raw materials. These monovalent hydrocarbon groups may have one or more heteroatoms in the molecular chain, such as ether groups, carbonyl groups, amino groups, and sulfide groups.

[0051] In the above general formula (4), R 8R represents an unsubstituted divalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, and more preferably 1 to 5 carbon atoms, which may contain a heteroatom. 8 As the divalent hydrocarbon group, R 3 The same substituents as those mentioned above can be mentioned. Among these, R 8 As the alkylene group, an unsubstituted alkylene group containing a linear ether group having 3 to 10 carbon atoms is preferred, and from the viewpoint of easy availability of raw materials, a 3-methyleneoxytrimethylene group and an 8-methyleneoxyoctamethylene group are more preferred. R 9 and R 10 R each independently represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, and more preferably 1 to 3 carbon atoms. 9 and R 10 As the monovalent hydrocarbon group, R 1 and R 2 The same substituents as those mentioned above can be mentioned. Among these, R 9 and R 10 As the alkyl group, an unsubstituted linear alkyl group or alkenyl group having 1 to 3 carbon atoms is more preferable, and from the viewpoint of easy availability of raw materials, a methyl group or an ethyl group is even more preferable. Furthermore, m is an integer of 0 to 3.

[0052] In the above general formula (5), R 11 represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms, which may contain a heteroatom. R 11The divalent hydrocarbon group may be linear, branched, or cyclic, and specific examples thereof include alkylene groups such as methylene, ethylene, trimethylene, tetramethylene, isobutylene, hexamethylene, octamethylene, decamethylene, dodecamethylene, octadecamethylene, cyclohexylene, neopentylene, and methylenecyclohexylene; alkenylene groups such as butynylene, propenylene, butenylene, hexenylene, and octenylene; arylene groups such as phenylene; and aralkylene groups such as methylenephenylene and methylenephenylenemethylene. Among these, R 11 As the alkylene group, an unsubstituted alkylene group having 2 to 10 carbon atoms is preferred, and from the viewpoint of easy availability of raw materials, a dimethylene group, a tetramethylene group, a methyleneoxydimethyleneoxymethylene group, or a methyleneoxytetramethyleneoxymethylene group is more preferred.

[0053] Some or all of the hydrogen atoms of these divalent hydrocarbon groups may be substituted with other substituents, such as R 1 and R 2 The same substituents as those mentioned above can be mentioned. Among these, the other substituents are more preferably an alkoxy group having 1 to 3 carbon atoms, a phenyl group, and a fluorine atom, particularly from the viewpoint of easy availability of raw materials. Furthermore, these divalent hydrocarbon groups may have one or more heteroatoms such as ether groups, carbonyl groups, amino groups, sulfide groups, etc., present in the molecular chain.

[0054] Specific examples of compound (3) include aliphatic epoxides such as ethylene oxide, propylene oxide, 1,2-epoxybutane, 1,2-epoxyhexane, 1,2-epoxyoctane, and 1,2-epoxydodecane; aromatic epoxides such as styrene oxide; glycidyl ethers such as allyl glycidyl ether, butyl glycidyl ether, and benzyl glycidyl ether; 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyldimethoxymethylsilane, 3-glycidyloxypropylmethoxydimethylsilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropyldiethoxymethylsilane, 3-glycidyloxypropylethoxydimethylsilane, and 8-glycidyloxyoctyl silane. Examples of suitable silyl group-containing epoxides include trimethoxysilane, 8-glycidyloxyoctyldimethoxymethylsilane, 8-glycidyloxyoctylmethoxydimethylsilane, 8-glycidyloxyoctyltriethoxysilane, 8-glycidyloxyoctyldiethoxymethylsilane, and 8-glycidyloxyoctylethoxydimethylsilane; and bifunctional epoxides such as 5-hexadiene diepoxide, 1,7-octadiene diepoxide, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 2,2'-bis(4-glycidyloxyphenyl)propane, and resorcinol diglycidyl ether.

[0055] The amount of carbon dioxide used in the above reaction is not particularly limited, but from the viewpoint of reducing the amount of exhaust gas, it is preferably in the range of 1.0 to 10.0 mol, more preferably 1.1 to 3.0 mol, per 1 mol of compound (3). Although there is no limitation on the pressure of carbon dioxide, it is preferably carried out at 0.09 to 0.11 MPa from the viewpoint that reaction equipment that can withstand pressure is not required. In addition, pressure may be applied for the purpose of shortening the reaction time, and in that case, the pressure is preferably 0.2 to 10.0 MPa, more preferably 0.2 to 8.0 MPa.

[0056] The amount of the zinc complex having a guanidine ligand immobilized on an inorganic carrier used in the above reaction is not particularly limited, but is preferably in the range of 0.001 to 0.1 mol, more preferably 0.01 to 0.05 mol, in terms of zinc atoms, per mol of compound (3).

[0057] From the viewpoint of reducing energy costs, the cycloaddition reaction is preferably carried out at room temperature (1 to 30° C.), preferably 10 to 30° C. Heating may be performed to shorten the reaction time, and in that case the reaction temperature is preferably 40 to 100° C., more preferably 40 to 70° C. The reaction time is not particularly limited, but is preferably 1 to 40 hours, more preferably 1 to 20 hours.

[0058] From the viewpoint of environmental friendliness, the cycloaddition reaction is preferably carried out without a solvent, but a solvent can be used if necessary. Examples of the solvent that can be used include hydrocarbon solvents such as benzene, toluene, and xylene; ether solvents such as diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 4-methyltetrahydropyran, and dioxane; ester solvents such as ethyl acetate and butyl acetate; aprotic polar solvents such as acetonitrile, N,N-dimethylformamide, and N-methylpyrrolidone; and chlorinated hydrocarbon solvents such as dichloromethane and chloroform. These solvents may be used alone or in combination.

[0059] In the above general formula (6), R' represents a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group having 1 to 18 carbon atoms which may contain a heteroatom, a group represented by the following general formula (4), or a group represented by the following general formula (7).

[0060] [ka] (In the formula, R 8 ~R 11 and m have the same meaning as above.)

[0061] In the above general formula (6), the monovalent hydrocarbon group for R' is the same as when R is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 18 carbon atoms which may contain a heteroatom.

[0062] Specific examples of compound (6) include aliphatic cyclic carbonates such as ethylene carbonate, propylene carbonate, 4-ethyl-1,3-dioxolan-2-one, 4-butyl-1,3-dioxolan-2-one, 4-hexyl-1,3-dioxolan-2-one, and 4-octyl-1,3-dioxolan-2-one; aromatic cyclic carbonates such as 4-phenyl-1,3-dioxolan-2-one; and 4-[(2-propen-1-yloxy)methyl]-1,3-dioxolan-2-one. alkoxymethyl cyclic carbonates such as 4-[(3-trimethoxysilyl)propoxymethyl]-1,3-dioxolan-2-one, 4-[(3-dimethoxymethylsilyl)propoxymethyl]-1,3-dioxolan-2-one, 4-[(3-dimethoxymethylsilyl)propoxymethyl]-1,3-dioxolan-2-one, 4-[(3-methoxydimethylsilyl)propoxymethyl]-1,3-dioxolan-2-one, 4-[(3-trimethoxy ... Solan-2-one, 4-[(3-triethoxysilyl)propoxymethyl]-1,3-dioxolan-2-one, 4-[(3-diethoxymethylsilyl)propoxymethyl]-1,3-dioxolan-2-one, 4-[(3-ethoxydimethylsilyl)propoxymethyl]-1,3-dioxolan-2-one, 4-[(8-trimethoxysilyl)octoxymethyl]-1,3-dioxolan-2-one, 4-[(8-dimethoxymethylsilyl)octoxymethyl]-1,3-dioxolan-2-one ]-1,3-dioxolan-2-one, 4-[(8-methoxydimethylsilyl)octoxymethyl]-1,3-dioxolan-2-one, 4-[(8-triethoxysilyl)octoxymethyl]-1,3-dioxolan-2-one, 4-[(8-diethoxymethylsilyl)octoxymethyl]-1,3-dioxolan-2-one, 4-[(8-ethoxydimethylsilyl)octoxymethyl]-1,3-dioxolan-2-one, etc. silyl group-containing cyclic carbonates such as 4-[(8-methoxydimethylsilyl)octoxymethyl]-1,3-dioxolan-2-one, 4-[(8-triethoxysilyl)octoxymethyl]-1,3-dioxolan-2-one, and 4-[(8-ethoxydimethylsilyl)octoxymethyl]-1,3-dioxolan-2-one;4,4'-(1,2-ethanediyl)bis(1,3-dioxolan-2-one), 4,4'-(1,4-butanediyl)bis(1,3-dioxolan-2-one), 4,4'-[(1,2-ethanediylbis(oxymethylene)]bis(1,3-dioxolan-2-one), 4,4'-[(1,4-butanediylbis(oxymethylene)]bis(1,3-dioxolan-2-one), 4,4'-[(1,6-hexanediylbis(oxymethylene)]bis( 1,3-dioxolan-2-one), 4,4'-[(2,2-dimethyl-1,3-propanediyl)bis(oxymethylene)]bis(1,3-dioxolan-2-one), 4,4'-[(1-methylethylidene)bis(4,1-phenyleneoxymethylene)]bis(1,3-dioxolan-2-one), 4,4'-[1,3-phenylenebis(oxymethylene)]bis(1,3-dioxolan-2-one), and other bifunctional cyclic carbonates;

[0063] The cyclic carbonate compound obtained by the production method of the present invention can be further purified by various purification methods such as distillation, filtration, washing, column separation, etc., depending on the desired quality, before use. Purification by distillation is particularly preferred to achieve high purity. [Example]

[0064] EXAMPLES The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited to the following examples. The reaction rate was expressed as an area ratio % obtained by gas chromatography analysis.

[0065] [1] Preparation of immobilized zinc complexes with guanidine ligands [Example 1-1] The inside of a four-neck flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was replaced with nitrogen, and 7.9 g (35.0 mmol) of zinc bromide and 150 mL of acetonitrile were charged and stirred at 25°C while nitrogen gas was passed through the open end at the top of the reflux condenser to prevent outside air from mixing in. While adjusting the internal temperature to 25-30°C, 19.4 g (70.0 mmol) of N-[3-(trimethoxysilyl)propyl]-N',N',N'',N''-tetramethylguanidine was added dropwise, and the mixture was stirred at 25°C for 2 hours. The resulting reaction mixture was added to 100.0 g of silica gel (trade name: Wakogel (registered trademark) C-200, Fujifilm Wako Pure Chemical Industries, Ltd.) that had been dried at 120°C / 30 Pa for 2 hours, and the mixture was stirred at 80°C for 3 hours. After cooling the reaction mixture to room temperature, it was filtered through a PTFE membrane with a 0.2 μm pore size (pressure of 0.3 MPa). The recovered silica gel was washed three times with a mixture of 70 mL of acetone and 30 mL of methanol to obtain a treated silica gel. This treated silica gel was dried at 70°C / 30 Pa for 2 hours to obtain 125.6 g of an immobilized zinc bromide complex having a guanidine ligand.

[0066] Elemental analysis confirmed that the obtained immobilized zinc bromide complex with guanidine ligands contained 5.70% carbon and 2.21% nitrogen. Furthermore, the zinc content of the immobilized zinc bromide complex with guanidine ligands was measured by ICP-OES and found to be 1.8% by mass. These analysis results indicated that the amount of guanidine moieties supported in the immobilized zinc bromide complex with guanidine ligands was 0.53 mmol / g, and the amount of zinc atoms supported was 0.28 mmol / g.

[0067] The IR spectrum of the immobilized zinc bromide complex having the N',N',N'',N''-tetramethylguanidine ligand was measured. The results are shown in Figure 1. For comparison, the IR spectrum of the raw material, N-[3-(trimethoxysilyl)propyl]-N',N',N'',N''-tetramethylguanidine, was also measured. The results are shown in Figure 2. As shown in Figures 1 and 2, the immobilized zinc bromide complex with N',N',N'',N''-tetramethylguanidine ligand exhibited a peak at 1590-1621 cm -1 In N-[3-(trimethoxysilyl)propyl]-N',N',N'',N''-tetramethylguanidine, a peak due to the C=N bond in the guanidine moiety is observed at 1622 cm -1 These results suggest that the tetramethylguanidine moiety is immobilized on the silica gel.

[0068] [Example 1-2] A four-neck flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was purged with nitrogen. Nitrogen gas was passed through the open end of the reflux condenser to prevent the inclusion of outside air. 50.0 g of silica gel (trade name: Wakogel® C-200, Fujifilm Wako Pure Chemical Industries, Ltd.) dried at 120°C / 30 Pa for 2 hours and 80 mL of toluene were added and stirred at 25°C. While adjusting the internal temperature to 25-30°C, 9.7 g (35.0 mmol) of N-[3-(trimethoxysilyl)propyl]-N',N',N'',N''-tetramethylguanidine was added dropwise, followed by stirring at 110°C for 3 hours. The reaction mixture was cooled to room temperature, and then 40 mL of a solution of 4.0 g (17.5 mmol) of zinc bromide in acetonitrile was added while adjusting the internal temperature to 25-30°C. The mixture was stirred at 25°C for 1 hour. The reaction mixture was filtered through a 0.2 μm pore PTFE membrane (0.3 MPa pressure), and the recovered silica gel was washed three times with a mixture of 35 mL of acetone and 15 mL of methanol to obtain a treated silica gel. The treated silica gel was dried at 70°C / 30 Pa for 2 hours to obtain 62.0 g of an immobilized zinc bromide complex bearing a guanidine ligand.

[0069] Elemental analysis confirmed that the obtained immobilized zinc bromide complex with guanidine ligands contained 5.54 mass% carbon and 1.98 mass% nitrogen. Furthermore, the zinc content of the immobilized zinc bromide complex with guanidine ligands was measured by ICP-OES and found to be 1.7 mass%. These analysis results indicated that the amount of guanidine moieties supported in the immobilized zinc bromide complex with guanidine ligands was 0.47 mmol / g, and the amount of zinc atoms supported was 0.26 mmol / g.

[0070] [Examples 1-3] The inside of a four-neck flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was replaced with nitrogen, and 79 g (350 mmol) of zinc bromide and 200 mL of acetonitrile were charged and stirred at 25°C while nitrogen gas was passed through the open end at the top of the reflux condenser to prevent outside air from mixing in. While adjusting the internal temperature to 25-30°C, 194 g (700 mmol) of N-[3-(trimethoxysilyl)propyl]-N',N',N'',N''-tetramethylguanidine was added dropwise, and the mixture was stirred at 25°C for 2 hours. The resulting reaction mixture was added to a suspension of 1,000.0 g of silica gel (trade name: CAriACT® Q-10, manufactured by Fuji Silysia Ltd.) dried at 120°C / 30 Pa for 2 hours in toluene (1,600 mL), and the mixture was stirred at 80°C for 3 hours. The reaction mixture was cooled to room temperature and then filtered through an 800 μm pore size SUS filter (pressure of 0.1-0.3 MPa). The recovered silica gel was washed three times with a mixture of 700 mL of acetone and 300 mL of methanol to obtain a treated silica gel. The treated silica gel was dried at 70°C / 30 Pa for 2 hours to obtain 1,202 g of an immobilized zinc bromide complex having a guanidine ligand.

[0071] Elemental analysis confirmed that the obtained immobilized zinc bromide complex having a guanidine ligand contained 4.99% carbon and 1.79% nitrogen. Furthermore, the zinc content of the immobilized zinc bromide complex having a guanidine ligand was measured by ICP-OES and found to be 1.7% by mass. These analysis results indicated that the amount of guanidine moieties supported in the immobilized zinc bromide complex having a guanidine ligand was 0.43 mmol / g, and the amount of zinc atoms supported was 0.26 mmol / g.

[0072] [Examples 1-4] The inside of a four-neck flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was replaced with nitrogen, and 11.8 g (52.5 mmol) of zinc bromide and 30 mL of acetonitrile were charged and stirred at 25°C while nitrogen gas was passed through the open end at the top of the reflux condenser to prevent outside air from mixing in. While adjusting the internal temperature to 25-30°C, 30.6 g (105 mmol) of N-[(triethoxysilyl)methyl]-N',N',N'',N''-tetramethylguanidine was added dropwise, and the mixture was stirred at 25°C for 2 hours. The resulting reaction mixture was added to a suspension of 150.0 g of silica gel (trade name: CAriACT® Q-10, manufactured by Fuji Silysia Co., Ltd.) dried at 120°C / 30 Pa for 2 hours in toluene (1600 mL), and the mixture was stirred at 80°C for 6 hours. After cooling the reaction mixture to room temperature, it was filtered through an 800 μm pore size SUS filter (pressure of 0.1-0.3 MPa). The recovered silica gel was washed three times with a mixture of 110 mL of acetone and 40 mL of methanol to obtain a treated silica gel. This treated silica gel was dried at 70°C / 30 Pa for 2 hours to obtain 180.0 g of an immobilized zinc bromide complex having a guanidine ligand.

[0073] Elemental analysis confirmed that the obtained immobilized zinc bromide complex with guanidine ligands contained 4.34 mass% carbon and 1.87 mass% nitrogen. Furthermore, the zinc content of the immobilized zinc bromide complex with guanidine ligands was measured by ICP-OES and found to be 1.4 mass%. These analysis results indicated that the amount of guanidine moieties supported in the immobilized zinc bromide complex with guanidine ligands was 0.45 mmol / g, and the amount of zinc atoms supported was 0.21 mmol / g.

[0074] [Examples 1-5] The inside of a four-neck flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was replaced with nitrogen, and 11.8 g (52.5 mmol) of zinc bromide and 30 mL of acetonitrile were charged and stirred at 25°C while nitrogen gas was passed through the open end at the top of the reflux condenser to prevent outside air from mixing in. While adjusting the internal temperature to 25-30°C, 40.9 g (105 mmol) of N-[8-(triethoxysilyl)octyl]-N',N',N'',N''-tetramethylguanidine was added dropwise, and the mixture was stirred at 25°C for 2 hours. The resulting reaction mixture was added to a suspension of 150.0 g of silica gel (trade name: CAriACT® Q-10, manufactured by Fuji Silysia Ltd.) dried at 120°C / 30 Pa for 2 hours in toluene (1600 mL), and the mixture was stirred at 80°C for 6 hours. After cooling the reaction mixture to room temperature, it was filtered through an 800 μm pore size SUS filter (pressure of 0.1-0.3 MPa). The recovered silica gel was washed three times with a mixture of 110 mL of acetone and 40 mL of methanol to obtain a treated silica gel. This treated silica gel was dried at 70°C / 30 Pa for 2 hours to obtain 180.6 g of an immobilized zinc bromide complex having a guanidine ligand.

[0075] Elemental analysis confirmed that the obtained immobilized zinc bromide complex with guanidine ligands contained 6.07% carbon and 1.32% nitrogen. Furthermore, the zinc content of the immobilized zinc bromide complex with guanidine ligands was measured by ICP-OES and found to be 1.6% by mass. These analysis results indicated that the amount of guanidine moieties supported in the immobilized zinc bromide complex with guanidine ligands was 0.31 mmol / g, and the amount of zinc atoms supported was 0.24 mmol / g.

[0076] [2] Production of cyclic carbonate compounds [Example 2-1] The inside of a four-neck flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was replaced with nitrogen, and 37.0 g (Zn: 10 mmol) of the immobilized zinc complex having a guanidine ligand synthesized in Example 1-1 and 57.1 g (500 mmol) of allyl glycidyl ether were charged and stirred while nitrogen gas was passed through the open end at the top of the reflux condenser to prevent outside air from mixing in. Next, the temperature was adjusted to 27°C, and carbon dioxide was bubbled into the reaction solution at normal pressure at a rate of 28 mL / min (1500 mmol over 20 hours) while stirring for 20 hours. A small amount of the reaction mixture was sampled, and the conversion was calculated by gas chromatography. The conversion rate from allyl glycidyl ether to 4-[(2-propen-1-yloxy)methyl]-1,3-dioxolan-2-one was 95.0%. The reaction mixture was filtered through a 0.2 μm pore size PTFE membrane (0.3 MPa pressure), and the recovered silica gel was washed three times with 37 mL of toluene. The filtrate was distilled at 0.2 kPa to obtain 4-[(2-propen-1-yloxy)methyl]-1,3-dioxolan-2-one in an isolated yield of 87.3% and a purity of >99.9%.

[0077] [Example 2-2] The inside of a four-neck flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was replaced with nitrogen, and nitrogen gas was passed through the open end at the top of the reflux condenser to prevent outside air from mixing in. 50.0 g (Zn: 13.5 mmol) of the immobilized zinc complex having a guanidine ligand synthesized in Example 1-1, 29.0 g (500 mmol) of propylene oxide, and 60 mL of acetonitrile were charged and stirred. Next, the temperature was adjusted to 25°C, and carbon dioxide was bubbled into the reaction solution at normal pressure at a rate of 28 mL / min (1500 mmol over 20 hours) while stirring for 20 hours. A small amount of the reaction mixture was sampled and the conversion rate calculated by gas chromatography. The conversion rate from propylene oxide to propylene carbonate was 95.0%. The reaction mixture was filtered through a 0.2 μm pore size PTFE membrane (0.3 MPa pressure), and the recovered silica gel was washed three times with 50 mL of acetonitrile. The filtrate was distilled at 1.2 kPa to obtain propylene carbonate in an isolated yield of 82.5% and with a purity of >99.9%.

[0078] [Example 2-3] The inside of a four-neck flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was replaced with nitrogen, and nitrogen gas was passed through the open end at the top of the reflux condenser to prevent outside air from mixing in. While this was done, 50.0 g (Zn: 13.5 mmol) of the immobilized zinc complex having a guanidine ligand synthesized in Example 1-1 and 92.0 g (500 mmol) of 2-[(7-octen-1-yloxy)methyl]oxirane were charged and stirred. Next, the temperature was adjusted to 70°C, and carbon dioxide was bubbled into the reaction solution at normal pressure at a rate of 62.2 mL / min (1334 mmol over 8 hours) while stirring for 8 hours. A small amount of the reaction mixture was sampled and the conversion calculated by gas chromatography. The conversion of 2-[(7-octen-1-yloxy)methyl]oxirane to 4-[(7-octen-1-yloxy)methyl]-1,3-dioxolan-2-one was 96.4%. The reaction mixture was cooled to room temperature and filtered through a 0.2 μm pore size PTFE membrane (0.3 MPa pressure). The recovered silica gel was washed three times with 50 mL of toluene. The filtrate was distilled at 30 Pa to obtain 4-[(7-octen-1-yloxy)methyl]-1,3-dioxolan-2-one in 90.2% isolated yield and 98.5% purity.

[0079] Furthermore, the reusability of the recovered silica gel, which is an immobilized zinc complex having a guanidine ligand, as a catalyst was confirmed. Specifically, the recovered silica gel was washed three times with a mixture of 70 mL of acetone and 30 mL of methanol, and then dried at 70 °C / 30 Pa for 2 hours. Using this silica gel, the cycloaddition reaction of 2-[(7-octen-1-yloxy)methyl]oxirane was carried out again using the same procedure as above. After the reaction, a small amount of the reaction mixture was sampled, and the conversion was calculated by gas chromatography. The conversion rate from 2-[(7-octen-1-yloxy)methyl]oxirane to 4-[(7-octen-1-yloxy)methyl]-1,3-dioxolan-2-one was 94.7%.

[0080] [Example 2-4] The inside of a four-neck flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was replaced with nitrogen, and 50.0 g (Zn: 13.5 mmol) of the immobilized zinc complex having a guanidine ligand synthesized in Example 1-1 and 118.0 g (500 mmol) of 3-glycidyloxypropyltrimethoxysilane were charged and stirred while nitrogen gas was passed through the open end at the top of the reflux condenser to prevent outside air from mixing in. Next, the temperature was adjusted to 70°C, and carbon dioxide was bubbled into the reaction solution at normal pressure at a rate of 62.2 mL / min (1334 mmol over 8 hours) while stirring for 8 hours. A small amount of the reaction mixture was sampled and the conversion calculated by gas chromatography. The conversion of 3-glycidyloxypropyltrimethoxysilane to 4-[(3-trimethoxysilyl)propoxymethyl]-1,3-dioxolan-2-one was 92.6%. The reaction mixture was cooled to room temperature and filtered through a 0.2 μm pore size PTFE membrane (0.3 MPa pressure). The recovered silica gel was washed three times with 50 mL of toluene. The filtrate was distilled at 30 Pa to obtain 4-[(3-trimethoxysilyl)propoxymethyl]-1,3-dioxolan-2-one in an isolated yield of 80.1% and a purity of 99.0%.

[0081] [Example 2-5] The inside of a four-neck flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was replaced with nitrogen, and while nitrogen gas was passed through the open end at the top of the reflux condenser to prevent outside air from mixing in, 50.0 g (Zn: 13.5 mmol) of the immobilized zinc complex having a guanidine ligand synthesized in Example 1-1 and 153.0 g (500 mmol) of 8-glycidyloxyoctyltrimethoxysilane were charged and stirred. Next, while adjusting the internal temperature to 70°C, carbon dioxide was bubbled into the reaction solution at normal pressure at a rate of 62.2 mL / min (1334 mmol over 8 hours) and stirred for 8 hours. A small amount of the reaction mixture was sampled and the conversion calculated by gas chromatography. The conversion of 8-glycidyloxyoctyltrimethoxysilane to 4-[(8-trimethoxysilyl)octoxymethyl]-1,3-dioxolan-2-one was 91.8%. The reaction mixture was cooled to room temperature and filtered through a 0.2 μm pore PTFE membrane (0.3 MPa pressure). The recovered silica gel was washed three times with 50 mL of toluene. The filtrate was distilled at 30 Pa to obtain 4-[(8-trimethoxysilyl)octoxymethyl]-1,3-dioxolan-2-one in 68.5% isolated yield and 98.9% purity.

[0082] [Example 2-6] The inside of a four-neck flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was replaced with nitrogen, and 50.0 g (Zn: 13.5 mmol) of the immobilized zinc complex having a guanidine ligand synthesized in Example 1-1 and 108.1 g (500 mmol) of neopentyl glycol diglycidyl ether were charged and stirred while nitrogen gas was passed through the open end of the upper part of the reflux condenser to prevent outside air from mixing in. Next, the temperature was adjusted to 70°C, and carbon dioxide was bubbled into the reaction solution at atmospheric pressure at a rate of 62.2 mL / min (2668 mmol in 16 hours) while stirring for 16 hours. The reaction mixture was filtered through a 0.2 μm pore size PTFE membrane (0.3 MPa pressure) while maintaining the temperature at 70°C, and the recovered silica gel was washed three times with 50 mL of toluene. The filtrate was concentrated using an evaporator and then dried at 100°C / 30 Pa for 1 hour to obtain 4,4'-[(2,2-dimethyl-1,3-propanediyl)bis(oxymethylene)]bis(1,3-dioxolan-2-one) in a yield of 99.3%.

[0083] The obtained 4,4'-[(2,2-dimethyl-1,3-propanediyl)bis(oxymethylene)]bis(1,3-dioxolan-2-one) 1 The H-NMR spectrum (deuterated chloroform solvent) was measured, and the results are shown in Figure 3. As shown in Figure 3, 1 In the H-NMR spectrum, no peaks derived from the starting material neopentyl glycol diglycidyl ether or the monocarbonate formed during the reaction were observed, confirming that the cycloaddition reaction was complete. In addition, there were almost no by-products in this reaction. Impurities included 0.11 moles of toluene per 1.0 mole of 4,4'-[(2,2-dimethyl-1,3-propanediyl)bis(oxymethylene)]bis(1,3-dioxolan-2-one). Converting this to a mass ratio, the purity of the resulting 4,4'-[(2,2-dimethyl-1,3-propanediyl)bis(oxymethylene)]bis(1,3-dioxolan-2-one) was 96.8%.

[0084] [Example 2-7] The inside of a four-neck flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was replaced with nitrogen, and nitrogen gas was passed through the open end at the top of the reflux condenser to prevent outside air from mixing in. While this was done, 13.9 g of the immobilized zinc complex having a guanidine ligand synthesized in Example 1-3 and 26.0 g (200 mmol) of butyl glycidyl ether were charged and stirred. Next, the temperature was adjusted to 70°C, and carbon dioxide was bubbled into the reaction solution at normal pressure at a rate of 24.9 mL / min (534 mmol over 8 hours) while stirring for 8 hours. A small amount of the reaction mixture was sampled, and the reaction rate was calculated by gas chromatography, which revealed that the reaction rate from butyl glycidyl ether to 4-butoxymethyl-1,3-dioxolan-2-one was 94.7%.

[0085] [Example 2-8] A cycloaddition reaction of butyl glycidyl ether and carbon dioxide was carried out under the same reaction conditions as in Example 2-7, except that the immobilized zinc complex having a guanidine ligand synthesized in Example 1-3 was changed to the immobilized zinc complex having a guanidine ligand synthesized in Example 1-4. A small amount of the reaction mixture was sampled, and the reaction rate was calculated by gas chromatography, which revealed that the reaction rate from butyl glycidyl ether to 4-butoxymethyl-1,3-dioxolan-2-one was 95.2%.

[0086] [Example 2-9] A cycloaddition reaction of butyl glycidyl ether and carbon dioxide was carried out under the same reaction conditions as in Example 2-7, except that the immobilized zinc complex having a guanidine ligand synthesized in Example 1-3 was changed to the immobilized zinc complex having a guanidine ligand synthesized in Example 1-5. A small amount of the reaction mixture was sampled, and the conversion was calculated by gas chromatography, which revealed that the conversion of butyl glycidyl ether to 4-butoxymethyl-1,3-dioxolan-2-one was 90.8%.

[0087] [Comparative Example 1] A carbonation reaction of allyl glycidyl ether was carried out under the same reaction conditions as in Example 2-1 using the silica gel-immobilized phosphonium bromide salt described in Patent Document 1. A silica gel-immobilized phosphonium bromide salt derived from tri(p-tolyl)phosphine and 3-bromopropyltriethoxysilane was synthesized according to the method described in Patent Document 1, except that the type of silica gel used was Wakogel (registered trademark) C-200 manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. The inside of a four-neck flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was replaced with nitrogen, and 37.0 g of the silica gel-immobilized phosphonium bromide salt obtained above and 57.1 g (500 mmol) of allyl glycidyl ether were charged and stirred while nitrogen gas was passed through the open end at the top of the reflux condenser to prevent outside air from mixing in. Next, the temperature was adjusted to 27°C, and carbon dioxide was bubbled into the reaction solution at normal pressure at a rate of 28 mL / min (1500 mmol over 20 hours) while stirring for 20 hours. A small amount of the reaction mixture was sampled and the conversion calculated by gas chromatography. The conversion of allyl glycidyl ether to 4-[(2-propen-1-yloxy)methyl]-1,3-dioxolan-2-one was 34.9%. The reaction mixture was filtered through a 0.2 μm pore size PTFE membrane (0.3 MPa pressure), and the recovered silica gel was washed three times with 37 mL of toluene. The filtrate was distilled at 0.2 kPa to obtain 4-[(2-propen-1-yloxy)methyl]-1,3-dioxolan-2-one in an isolated yield of 20.5% and a purity of 99.8%.

[0088] As described above, in Examples 2-1 and 2-2, even though the reactions were carried out under mild conditions of normal pressure and room temperature, in both cases the corresponding cyclic carbonate compounds were produced at high reaction rates and isolated in high yield and purity. These results demonstrate that the immobilized zinc complex having a guanidine ligand according to the present invention exhibits excellent catalytic activity even under mild conditions. In Examples 2-3 to 2-6, the reaction temperature was set to 70°C to shorten the aging time, and the cycloaddition reaction proceeded more smoothly. In all cases, the cyclic carbonate compound was obtained in high yield and with high purity.

[0089] Furthermore, in Example 2-3, the reusability of the immobilized zinc complex having a guanidine ligand according to the present invention as a catalyst was confirmed. As a result, it was found that the reaction rate from 2-[(7-octen-1-yloxy)methyl]oxirane to 4-[(7-octen-1-yloxy)methyl]-1,3-dioxolan-2-one in the second use of this catalyst was comparable to that in the first use of the catalyst. Therefore, it was demonstrated that the immobilized zinc complex having a guanidine ligand according to the present invention can be recovered and reused with almost no decrease in catalytic activity.

[0090] In Examples 2-7 to 2-9, the catalytic activity of immobilized zinc complexes with different lengths of linker moiety in the guanidine ligand was compared. When a cycloaddition reaction of butyl glycidyl ether with carbon dioxide was carried out under the same reaction conditions, the conversion rate from butyl glycidyl ether to 4-butoxymethyl-1,3-dioxolan-2-one was highest for the immobilized zinc complexes with guanidine ligands of an octamethylene linker (Example 2-9), followed by a trimethylene linker (Example 2-7), and finally a monomethylene linker (Example 2-8). This indicates that the guanidine ligand of the immobilized zinc complex according to the present invention exhibits higher catalytic activity the fewer the number of carbon atoms in the linker moiety.

[0091] On the other hand, in Comparative Example 1, a cycloaddition reaction of allyl glycidyl ether and carbon dioxide was carried out at room temperature under normal pressure, as in Example 2-1, using a phosphonium bromide salt immobilized on silica gel as a catalyst. As a result, the target product, 4-[(2-propen-1-yloxy)methyl]-1,3-dioxolan-2-one, was produced only at a low reaction rate, and the isolation yield was accordingly extremely low.

Claims

1. The following general formula (1) 【Chemistry 1】 (In the formula, R 1 and R 2 each independently represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms; R 3 represents an unsubstituted divalent hydrocarbon group having 1 to 10 carbon atoms, and R 4 ~R 7 are each independently a hydrogen atom or an unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and R 4 and R 5 , R 6 and R 7 and R 4 and R 6 may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded, and n represents an integer of 0 to 2. a guanidine-containing alkoxysilane compound represented by the following general formula (2): ZnX 2 (2) (In the formula, X represents a halogen atom.) and an inorganic carrier, An immobilized zinc complex having a guanidine ligand, in which a nitrogen atom of a guanidine-derived portion of the guanidine-containing alkoxysilane compound and a zinc atom of the zinc halide are bonded via a coordinate bond, and a silicon atom of the zinc complex is immobilized to an inorganic carrier via a covalent bond with an oxygen atom on the surface of the inorganic carrier.

2. The following general formula (1) 【Chemistry 2】 (In the formula, R 1 ~R 7 and n have the same meaning as above. and a guanidine-containing alkoxysilane compound represented by the following general formula (2): ZnX 2 (2) (In the formula, X has the same meaning as above.) and then mixing the resulting zinc complex having the guanidine ligand with an inorganic carrier to form a covalent bond between the silicon atom of the zinc complex having the guanidine ligand and the oxygen atom on the surface of the inorganic carrier, thereby immobilizing the zinc complex on the inorganic carrier.

3. The following general formula (1) 【Transformation 3】 (In the formula, R 1 ~R 7 and n have the same meaning as above. and an inorganic carrier to form a covalent bond between an oxygen atom present on the surface of the inorganic carrier and a silicon atom of the guanidine-containing alkoxysilane compound, and to immobilize the guanidine-containing alkoxysilane compound on the inorganic carrier to obtain an organic-inorganic composite material. Then, the organic-inorganic composite material is mixed with a compound represented by the following general formula (2): ZnX 2 (2) (In the formula, X has the same meaning as above.) and combining a zinc halide represented by the formula (I) with a nitrogen atom of the guanidine moiety contained in the organic-inorganic composite material and a zinc atom of the zinc halide via a coordinate bond to obtain a zinc complex having a guanidine ligand.

4. The following general formula (3) 【Chemistry 4】 [In the formula, R represents a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group having 1 to 18 carbon atoms which may contain a heteroatom, a group represented by the following general formula (4), or a group represented by the following general formula (5): 【Transformation 5】 (In the formula, R 8 represents an unsubstituted divalent hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom, R 9 and R 10 each independently represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and m represents an integer of 0 to 3. 【Transformation 6】 (In the formula, R 11 represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 20 carbon atoms, which may contain a heteroatom. and carbon dioxide in the presence of a catalyst, 【Transformation 7】 [In the formula, R′ represents a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group having 1 to 18 carbon atoms which may contain a heteroatom, a group represented by the following general formula (4), or a group represented by the following general formula (7): 【Transformation 8】 (In the formula, R 8 ~R 10 and m have the same meanings as above. 【Chemistry 9】 (In the formula, R 11 represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 20 carbon atoms, which may contain a heteroatom. In a method for producing a cyclic carbonate compound represented by the following formula: A method for producing a cyclic carbonate compound, which uses the immobilized zinc complex having a guanidine ligand according to claim 1 as the catalyst.

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