Method for producing cyclic carbonate

Abstract

To provide a method for producing cyclic carbonate by reacting a polyol with carbon dioxide, at a reduced cost, while inhibiting the formation of acetylene as a by-product.SOLUTION: A method for producing cyclic carbonate includes the step of reacting a polyol with carbon dioxide in the presence of a zinc compound and a reusable dehydrant.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing a cyclic carbonate. [Background technology]

[0002] Cyclic carbonates, especially those with five-membered rings, are used as polar aprotic solvents, industrial lubricants, electrolytes for lithium-ion batteries, building blocks for the synthesis of polymeric materials, monomers for the production of polycarbonates, and other fine chemicals. Cyclic carbonates can be synthesized by the reaction of diols, as well as halides, alkynes, alkenes, and epoxides, with various carbonyl sources. In recent years, the synthesis of glycerol carbonate using glycerin, a biomass resource, and CO2 as raw materials has attracted attention. Patent Document 1 discloses a method for producing a cyclic carbonate by reacting a polyol with carbon dioxide in the presence of a zinc compound and calcium carbide. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-138661 Summary of the Invention [Problem to be solved by the invention]

[0004] The method described in Patent Document 1 has the problem that calcium carbide used as a dehydrating agent in the reaction cannot be regenerated or reused, which increases the cost of the reaction, and also produces explosive acetylene as a by-product. Therefore, an object of the present invention is to provide a method for producing a cyclic carbonate by reacting a polyol with carbon dioxide, which can reduce costs and prevent the generation of acetylene as a by-product. [Means for solving the problem]

[0005] As a result of intensive research aimed at solving the above problems, the present inventors have found that a cyclic carbonate can be produced by reacting a polyol with carbon dioxide using a renewable dehydrating agent. The present invention was completed based on this finding and includes the following aspects: That is, one aspect of the present invention is [1] The present invention relates to a method for producing a cyclic carbonate, which comprises a reaction step of reacting a polyol with carbon dioxide in the presence of a zinc compound and a renewable dehydrating agent. In one embodiment, the method for producing a cyclic carbonate of the present invention includes the steps of: [2] The manufacturing method according to [1] above, The regenerable dehydrating agent is calcium oxide. In one embodiment, the method for producing a cyclic carbonate of the present invention includes the steps of: [3] The manufacturing method according to [1] or [2] above, The method is characterized in that the regenerable dehydrating agent is used in the reaction step in an amount ranging from 4 to 40 molar equivalents per mole of the polyol. In one embodiment, the method for producing a cyclic carbonate of the present invention includes the steps of: [4] The manufacturing method according to any one of [1] to [3] above, The reaction step is characterized in that mechanical stirring is used. In one embodiment, the method for producing a cyclic carbonate of the present invention includes the steps of: [5] The manufacturing method according to any one of [1] to [4] above, The method for producing the zinc compound is at least one of zinc iodide, zinc trifluoromethanesulfonate, and zinc p-toluenesulfonate. In one embodiment, the method for producing a cyclic carbonate of the present invention includes the steps of: [6] The manufacturing method according to any one of [1] to [5] above, In the reaction step, the polyol and carbon dioxide are reacted in the presence of at least one ligand represented by the following chemical formula: [ka] In one embodiment, the method for producing a cyclic carbonate of the present invention includes the steps of: [7] The manufacturing method according to any one of [1] to [6] above, The production method, wherein the reaction step is carried out using N-methyl-2-pyrrolidone as a solvent. In one embodiment, the method for producing a cyclic carbonate of the present invention includes the steps of: [8] The manufacturing method according to any one of [1] to [7] above, The reaction step is carried out at a temperature of 165 to 180°C. In one embodiment, the method for producing a cyclic carbonate of the present invention includes the steps of: [9] The manufacturing method according to any one of [1] to [8] above, The method for producing a cyclic carbonate comprises carrying out the reaction step at a carbon dioxide pressure of 2 to 5 MPa. [Effects of the Invention]

[0006] According to the production method of the present invention, the dehydrating agent used in the method for producing a cyclic carbonate by reacting a polyol with carbon dioxide can be recycled, thereby reducing costs. Furthermore, according to the production method of the present invention, the generation of acetylene as a by-product can be prevented. DETAILED DESCRIPTION OF THE INVENTION

[0007] A method for producing a cyclic carbonate according to an embodiment of the present invention includes a reaction step of reacting a polyol with carbon dioxide in the presence of a zinc compound and a renewable dehydrating agent. Examples of cyclic carbonates obtainable by this method include ethylene carbonate, propylene carbonate, butylene carbonate, glycerol carbonate, and butanetriol carbonate.

[0008] Zinc compounds function as catalysts. Examples of zinc compounds include zinc acetate (Zn(CH3COO)2) (hereinafter sometimes referred to as "Zn(OAc)2"), zinc sulfate (ZnSO4), zinc chloride (ZnCl2), zinc bromide (ZnBr2), zinc iodide (ZnI2), zinc trifluoromethanesulfonate (Zn(CF3SO3)2) (hereinafter sometimes referred to as "Zn(OTf)2"), and zinc p-toluenesulfonate (Zn(C7H7O3S)2) (hereinafter sometimes referred to as "Zn(Tos)2"). Among these, ZnI2, Zn(OTf)2, and Zn(Tos)2 are preferred because they produce cyclic carbonates in high yield.

[0009] Calcium oxide can be used as a renewable dehydrating agent. When polyols and carbon dioxide react to produce cyclic carbonates, water is produced as a by-product. The renewable dehydrating agent removes the by-product water from the reaction system, allowing the reaction of polyols and carbon dioxide to produce cyclic carbonates to proceed. The renewable dehydrating agent is preferably used in an amount of 4 to 40 molar equivalents, more preferably 10 to 40 molar equivalents, and most preferably 16 to 30 molar equivalents, per mole of polyol.

[0010] Examples of polyols include diols and triols. Examples of diols include glycols represented by the following chemical formula. Examples of triols include 1,2,3-propanetriol (glycerol) and 1,2,4-butanetriol.

[0011] [ka]

[0012] The reaction step of this embodiment can be carried out, for example, by filling a reaction vessel containing a zinc compound, a renewable dehydrating agent, a polyol, and a solvent with carbon dioxide, but the embodiment of the reaction step is not particularly limited. From the viewpoint of sufficiently progressing the reaction, the temperature in the reaction step (reaction temperature) is preferably 100 to 200°C, more preferably 150 to 180°C, and even more preferably 165 to 180°C, but is not particularly limited. When the reaction step is carried out at a reaction temperature of 165 to 180°C, a cyclic carbonate can be obtained in high yield.

[0013] The carbon dioxide pressure in the reaction step is preferably 0.5 to 30 MPa, more preferably 1 to 10 MPa, and even more preferably 3 to 5 MPa, but is not particularly limited. When the reaction step is carried out at a carbon dioxide pressure of 3 to 5 MPa, a cyclic carbonate can be obtained in high yield. The reaction step time (reaction time) varies depending on conditions such as the type of polyol, reaction temperature, and carbon dioxide pressure, but is preferably 4 to 48 hours.

[0014] The solvent used in the reaction step is not particularly limited as long as it does not interfere with the production of the cyclic carbonate, and no solvent may be used. Examples of solvents used in the reaction step include hydrocarbons and ethers. Specific examples include acetonitrile (MeCN), tetrahydrofuran (THF), toluene, N,N'-dimethylformamide (DMF), N,N'-dimethylacetamide (DMAc), methyl ethyl ketone (MEK), and N-methyl-2-pyrrolidone (NMP). Among these, DMAc and NMP are preferred, with NMP being particularly preferred, as this allows the production of the cyclic carbonate in high yield.

[0015] In a preferred embodiment, the reaction step uses mechanical stirring. The means that can be used for mechanical stirring are not limited as long as the reaction of producing a cyclic carbonate from a polyol and carbon dioxide is promoted, and any known means can be used.

[0016] In the reaction step, the polyol may be reacted with carbon dioxide in the presence of at least one ligand represented by the following chemical formula, because the yield of the cyclic carbonate is improved.

[0017] [ka] [Example]

[0018] <Example 1-1> Glycerin (46 mg, 0.5 mmol), NMP (3 mL), Zn(OTf) (5.0 mol%, 0.025 mmol), 1,10-phenanthroline (15 mol%, 0.075 mmol), and calcium oxide (280 mg, 5 mmol) were placed in a 10 mL stainless steel autoclave equipped with a 10 mm oval PTFE resin magnetic stir bar. The autoclave was then filled with CO2 (room temperature, 3 MPa), sealed, and heated and stirred at a reaction temperature of 180 °C for 16 hours to obtain glycerol carbonate. The yield of glycerol carbonate was determined using mesitylene (50 mg) as an internal standard. 1 The results were calculated by H-NMR measurement, and are shown in Table 1.

[0019] <Examples 1-2 to 1-5> The reaction was carried out in the same manner as in Example 1-1, except that the additive (5 mmol) shown in Table 1 was used instead of calcium oxide, and the yield of glycerol carbonate was calculated. The yield of glycerol carbonate was calculated using mesitylene (50 mg) as an internal standard substance. 1 The results were calculated by H-NMR measurement, and are shown in Table 1.

[0020] <Examples 1-6> The reaction was carried out in the same manner as in Example 1-1, except that MS4A (200 mg) was used instead of calcium oxide, and the yield of glycerol carbonate was calculated. The yield of glycerol carbonate was calculated using mesitylene (50 mg) as an internal standard substance. 1 The results were calculated by H-NMR measurement, and are shown in Table 1. [ka] [Table 1]

[0021] <Example 2-1> Glycerin (46 mg, 0.5 mmol), NMP (3 mL), Zn(OTf) (5.0 mol%, 0.025 mmol), 1,10-phenanthroline (15 mol%, 0.075 mmol), and calcium oxide (280 mg, 5 mmol) were placed in a 10 mL stainless steel autoclave equipped with a 10 mm oval PTFE resin magnetic stir bar. The autoclave was then filled with CO2 (room temperature, 1 MPa), sealed, and heated and stirred at a reaction temperature of 180 °C for 16 hours to obtain glycerol carbonate. The yield of glycerol carbonate was determined using mesitylene (50 mg) as an internal standard. 1 The results were calculated by H-NMR measurement, and are shown in Table 2.

[0022] <Examples 2-2 to 2-7> The reaction was carried out in the same manner as in Example 2-1, except that the CO2 charging pressure and reaction time were changed as shown in Table 2, and the yield of glycerol carbonate was calculated. The yield of glycerol carbonate was calculated using mesitylene (50 mg) as an internal standard substance. 1 The results were calculated by H-NMR measurement, and are shown in Table 2. [ka] [Table 2]

[0023] <Example 3-1> Glycerin (46 mg, 0.5 mmol), NMP (3 mL), Zn(OTf) (5.0 mol%, 0.025 mmol), 1,10-phenanthroline (15 mol%, 0.075 mmol), and calcium oxide (112 mg, 2 mmol) were placed in a 10 mL stainless steel autoclave equipped with a 10 mm oval PTFE resin magnetic stir bar. The autoclave was then filled with CO2 (room temperature, 5 MPa), sealed, and heated and stirred at a reaction temperature of 180 °C for 64 hours to obtain glycerol carbonate. The yield of glycerol carbonate was determined using mesitylene (50 mg) as an internal standard. 1 The results were calculated by H-NMR measurement, and are shown in Table 3.

[0024] <Examples 3-2 to 3-4> The reaction was carried out in the same manner as in Example 3-1, except that the amount of calcium oxide added was changed as shown in Table 3, and the yield of glycerol carbonate was calculated. The yield of glycerol carbonate was calculated using mesitylene (50 mg) as an internal standard substance. 1 The results were calculated by H-NMR measurement, and are shown in Table 3.

[0025] <Examples 3-5> Six 3 mm diameter stainless steel balls, glycerin (46 mg, 0.5 mmol), NMP (3 mL), Zn(OTf) (5.0 mol%, 0.025 mmol), 1,10-phenanthroline (15 mol%, 0.075 mmol), and calcium oxide (280 mg, 5 mmol) were placed in a 10 mL stainless steel autoclave equipped with a mechanical stirrer. The autoclave was then filled with CO2 (room temperature, 5 MPa), sealed, and heated and stirred at a reaction temperature of 180 °C for 16 hours to obtain glycerol carbonate. The yield of glycerol carbonate was determined using mesitylene (50 mg) as an internal standard. 1 The results were calculated by H-NMR measurement, and are shown in Table 3.

[0026] <Examples 3-6 to 3-12> The reaction was carried out in the same manner as in Example 3-5, except that the amount of calcium oxide charged, the reaction time, and the reaction temperature were changed as shown in Table 3, and the yield of glycerol carbonate was calculated. The yield of glycerol carbonate was calculated using mesitylene (50 mg) as an internal standard substance. 1 The results were calculated by H-NMR measurement, and are shown in Table 3. [ka] [Table 3]

[0027] <Examples 4-1 to 4-4> The reaction was carried out in the same manner as in Example 3-11, except that the polyols shown in Table 1 were used instead of glycerin, and the yield of the cyclic carbonate was calculated. The yield of the cyclic carbonate was calculated using mesitylene (50 mg) as an internal standard substance. 1 The results were calculated by H-NMR measurement, and are shown in Table 4. [ka] [Table 4]

Claims

1. A method for producing a cyclic carbonate, comprising a reaction step of reacting a polyol with carbon dioxide in the presence of a zinc compound and a renewable dehydrating agent, the regenerable dehydrating agent is calcium oxide; In the reaction step, the calcium oxide is used in an amount of 10 to 40 molar equivalents relative to 1 mole of polyol, Furthermore, the production method further comprises using mechanical stirring in the reaction step.

2. The method of claim 1, The zinc compound is at least one of zinc iodide, zinc trifluoromethanesulfonate, and zinc p-toluenesulfonate.

3. The manufacturing method according to claim 1 or 2, In the reaction step, the polyol and carbon dioxide are reacted in the presence of at least one ligand represented by the following chemical formula: 【Chemistry 1】

4. The manufacturing method according to any one of claims 1 to 3, The reaction step is carried out using N-methyl-2-pyrrolidone as a solvent.

5. The manufacturing method according to any one of claims 1 to 4, The reaction step is carried out at a temperature of 165 to 180°C.

6. The manufacturing method according to any one of claims 1 to 5, The method for producing a cyclic carbonate, wherein the reaction step is carried out at a carbon dioxide pressure of 2 to 5 MPa.

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