Method for producing 2-furonitrile and method for producing carbonate ester

Abstract

The present invention provides a method for producing 2-furonitrile by dehydrating 2-furamide in the presence of an Mo / SiO2 catalyst in which molybdenum (Mo) is supported on a carrier formed from SiO2. Further, a preferred embodiment of the present invention involves dehydration in the presence of a desiccant such as a molecular sieve.

Description

[Technical Field]

[0001] The present invention relates to a method for producing 2-furonitrile and a method for producing a carbonate ester. [Background technology]

[0002] Carbonate ester is a general term for compounds in which one or both of the two hydrogen atoms of carbonate CO(OH)2 are replaced with an alkyl or aryl group, and has the structure RO-C(=O)-OR' (R and R' represent saturated or unsaturated hydrocarbon groups). Carbonate esters are extremely useful compounds, used as additives in gasoline to improve octane numbers, in diesel fuel to reduce particles in exhaust gases, and as alkylating agents, carbonylating agents, and solvents in the synthesis of resins and organic compounds such as polycarbonates, urethanes, pharmaceuticals, and pesticides, as well as raw materials for electrolytes in lithium-ion batteries, lubricating oil raw materials, and oxygen scavengers to prevent rust in boiler piping.

[0003] Conventional methods for producing carbonate esters have mainly involved the direct reaction of alcohol with phosgene as a carbonyl source. Because this method uses highly toxic and corrosive phosgene, careful handling, including transportation and storage, is required. Maintenance and safety of production facilities is also costly. Furthermore, halogens such as chlorine are present in the raw materials and catalysts used in this method, resulting in trace amounts of halogens that cannot be removed by simple purification processes. For applications in gasoline additives, diesel fuel additives, and electronic materials, halogens may cause corrosion, requiring thorough purification processes to reduce the halogens present in the carbonate ester to an extremely low level. Furthermore, because this method uses phosgene, which is highly toxic to the human body, government guidance has recently been tightened, prohibiting the establishment of new production facilities for this method. Therefore, a new method for producing carbonate esters without using phosgene is highly desirable.

[0004] Therefore, a method for directly synthesizing carbonate esters from alcohol and carbon dioxide using a heterogeneous catalyst is also known. In this method, the use of 2-cyanopyridine or benzonitrile as a hydrating agent has been investigated to significantly improve the amount and rate of carbonate ester production, facilitate the reaction under pressure close to atmospheric pressure, and accelerate the reaction rate (see Patent Documents 1 and 2). However, there are still areas that need improvement in the methods for treating and utilizing by-products such as benzamide. For example, the use of benzamide, which is produced by the reaction of benzonitrile with water, is limited to certain pharmaceutical and agrochemical intermediates. Therefore, in the production of carbonate esters using benzonitrile as a hydrating agent, it is desirable to regenerate the by-product benzamide into benzonitrile and reuse it. However, the challenge was to carry out this regeneration reaction with high selectivity (because the generation of by-products would make it difficult to reuse it as a hydrating agent) and high yield (because a low yield would result in a large amount of residual benzamide, which would increase the amount of separation work required from benzonitrile and increase the burden).

[0005] As described above, in view of the fact that there are points to be improved in the regeneration of benzamides or the like into benzonitriles or the like, a method for performing the regeneration without using strong reagents and while suppressing the generation of by-products has been known (Patent Document 3). However, this method requires 400 hours to produce (regenerate) a nitrile by dehydrating the amide compound, which is not balanced with the carbonate synthesis reaction, which is completed in 24 hours, meaning that it cannot be used in combination. In addition, extraction and filtration are required to separate the catalyst into solid and liquid forms, making the process long and complicated, which are areas that need improvement. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-77113 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-162523 [Patent Document 3] WO2015 / 099053 publication Summary of the Invention [Problem to be solved by the invention]

[0007] In view of the above-mentioned problems of the conventional art, an object of the present invention is to provide a method for regenerating a nitrile by dehydration of an amide compound, which enables a dehydration reaction that suppresses the generation of by-products and selectively gives a target compound in high yield. Another object of the present invention is to realize an efficient method for producing a carbonate ester by applying the above-mentioned method for producing (regenerating) a nitrile compound to a method for producing a carbonate ester. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present inventors have conducted extensive research into a method for producing a nitrile compound by dehydrating an amide compound, and have found that by dehydrating 2-furoamide in the presence of a specific catalyst, the generation of by-products can be suppressed and the target compound, 2-furonitrile, can be selectively obtained in high yield. This makes it possible to balance the regeneration rate of an amide compound to a nitrile compound by a dehydration reaction with the synthesis rate of a carbonate ester from CO2 and an alcohol using a nitrile compound, i.e., to establish a commercial process that combines the dehydration reaction and the carbonate ester synthesis reaction. Based on this, the present inventors further investigated the application of the above findings to a method for producing a carbonate ester. That is, the present invention is as follows. <1> This is a method for producing 2-furonitrile by dehydrating 2-furoamide in the presence of a Mo / SiO2 catalyst, which is a catalyst in which molybdenum (Mo) is supported on a support made of SiO2. [ka] <2> Furthermore, the dehydration is carried out in the presence of a desiccant. <1> This is a method for producing 2-furonitrile described in <3> The desiccant is a molecular sieve. <2> This is a method for producing 2-furonitrile described in <4> The above, wherein 2-furocarboxylic acid is produced together with the 2-furonitrile. <1> from <3> The method for producing 2-furonitrile according to any one of the above items is also provided. [ka] <5> a first reaction step including a carbonate ester production reaction in which an alcohol is reacted with carbon dioxide in the presence of a solid catalyst, 2-furonitrile, and a solvent to produce a carbonate ester and water, and a hydration reaction in which the produced water is hydrated with the 2-furonitrile to produce 2-furamide; a second reaction step in which, after separating the 2-furamide from the reaction system of the first reaction step, the 2-furamide is dehydrated in the presence of a Mo / SiO catalyst in which molybdenum (Mo) is supported on a support made of SiO to regenerate 2-furonitrile; The method for producing a carbonate ester is characterized in that at least a portion of the 2-furonitrile regenerated in the second reaction step is used in the first reaction step. <6> Furthermore, the dehydration is carried out in the presence of a desiccant. <5> 1. A method for producing a carbonate ester according to claim 1. <7> The desiccant is a molecular sieve. <6> 1. A method for producing a carbonate ester according to claim 1. <8> The alcohol includes an alcohol having 1 to 6 carbon atoms. <5> from <7> 1. The method for producing a carbonate ester according to claim 1, wherein the carbonic acid ester is a carboxylic acid ester. <9> The solid catalyst contains at least one of CeO2 and ZrO2. <5> from <8> 1. The method for producing a carbonate ester according to claim 1, wherein the carbonic acid ester is a carboxylic acid ester. <10> In the first reaction step, a solvent having a boiling point higher than that of the 2-furamide produced is used. <5> from <9> 1. The method for producing a carbonate ester according to claim 1, wherein the carbonic acid ester is a carboxylic acid ester. <11> The solvent comprises at least one of dialkylbenzene, alkylnaphthalene, and diphenylbenzene. <10> 1. A method for producing a carbonate ester according to claim 1. [Effects of the Invention]

[0009] As described above, according to the present invention, it is possible to efficiently produce (regenerate) a nitrile compound from an amide compound. That is, in the dehydration reaction of the amide compound for the regeneration, the generation of by-products can be suppressed, and the target compound can be selectively obtained in a high yield. Therefore, according to the present invention, it is possible to significantly shorten the reaction time of the dehydration reaction for regenerating a nitrile compound compared to conventional methods. Furthermore, according to the present invention, by producing a nitrile compound as described above, an efficient method for producing a carbonate ester can also be realized. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing a reactor (furnace) used in Examples and Comparative Examples. DETAILED DESCRIPTION OF THE INVENTION

[0011] Preferred embodiments of the present invention will be described in detail below. <Method of producing 2-furonitrile> A method for producing 2-furonitrile according to one embodiment of the present invention is a method for producing 2-furonitrile by dehydrating 2-furamide in the presence of a Mo / SiO catalyst in which molybdenum (Mo) is supported on a SiO support.

[0012] [ka]

[0013] Regarding the method for producing the catalyst used in the above-mentioned dehydration reaction of the present invention, the following example will be given. Commercially available powdered or spherical SiO2 can be used as the support. To ensure uniform loading of the active metal molybdenum (Mo), it is preferable to size the SiO2 to 100 mesh (0.15 mm) or less, and to remove moisture, pre-calcination is preferably carried out in air at 700°C for 1 hour. SiO2 also comes in various forms, but SiO2 with a larger surface area is preferred because it allows for higher dispersion of molybdenum (Mo) and improves the production of 2-furonitrile. Specifically, SiO2 with a surface area of ​​300 m 2 / g or more is preferable. However, the surface area of ​​the catalyst after preparation may be lower than the surface area of ​​SiO2 alone due to the interaction between SiO2 and molybdenum (Mo), etc. In such cases, it is preferable that the surface area of ​​the catalyst after production is less than 150 m 2 / g or more. Molybdenum (Mo), which serves as an active species, can be supported by an impregnation method such as an incipient wetness method or an evaporation-to-dryness method.

[0014] The metal salt that serves as the catalyst precursor may be any water-soluble compound. The catalyst can be used by impregnating a carrier with an aqueous solution of the basic metal precursor, followed by drying and calcination. The calcination temperature is preferably 400 to 600°C, depending on the precursor used.

[0015] The amount of catalyst supported can be set as appropriate, but for example, it is preferable to set the amount of molybdenum (Mo) oxide supported, converted to metal, based on the total catalyst weight to about 0.1 to 1.5 mmol / g, particularly about 0.1 to 1 mmol / g. If the amount supported is greater than this, the activity may decrease.

[0016] The amount of catalyst used during the reaction can be set as appropriate, but is preferably 20 to 150 parts by mass, more preferably 30 to 130 parts by mass, per 100 parts by mass of 2-furamide used.

[0017] The catalyst used in the present invention is preferably a catalyst in which only molybdenum (Mo) oxide is supported on a support made of SiO2, but it may contain unavoidable impurities other than the above elements that are mixed in during the catalyst production process, etc. However, it is desirable to minimize the inclusion of impurities.

[0018] The catalyst used in the present invention, in which molybdenum (Mo) oxide, which serves as an active species, is supported on a carrier, may be in the form of either a powder or a molded body. In the case of a molded body, it may be in any shape, such as a sphere, pellet, cylinder, ring, wheel, or granule.

[0019] In the method for producing 2-furonitrile using a catalyst of the present invention, the reaction format is not particularly limited, and any of a batch reactor, a semi-batch reactor, or a flow reactor such as a continuous tank reactor or a tubular reactor may be used. The catalyst may be either a fixed bed or a slurry bed.

[0020] Typical reaction conditions for the method for producing 2-furonitrile of the present invention include a reaction temperature of 160 to 230°C, a pressure of from normal pressure (101.3 (kPa) (760 Torr)) to reduced pressure (1.33 (kPa) (10 Torr)), and a reaction time of several hours to about 100 hours, but are not particularly limited thereto. For example, the reaction liquid temperature is preferably 170 to 220° C., more preferably 180 to 210° C. The reaction time is preferably 6 to 90 hours, more preferably 10 to 80 hours, and particularly preferably 20 to 75 hours. Regarding the pressure, normal pressure is preferred, since it does not require a pressure reducing device and is energy efficient.

[0021] In the method for producing 2-furonitrile of the present invention, dehydration of 2-furoamide is preferably carried out in the presence of a desiccant in addition to the Mo / SiO2 catalyst. The type of desiccant is not particularly limited, but molecular sieves are preferably used. When using molecular sieves as dehydrating agents, there are no particular limitations on the type or shape, but for example, 3A, 4A, 5A, or other generally highly water-absorbent molecular sieves in spherical or pellet form can be used. For example, Zeolum manufactured by Tosoh Corporation is suitable. It is also preferable to dry the molecular sieves beforehand, preferably at 300 to 500°C for about an hour.

[0022] [ka]

[0023] In the present invention, the dehydration reaction of 2-furamide may produce the above-mentioned 2-furancarboxylic acid as a by-product due to decomposition of 2-furamide. However, the reaction solution after the dehydration reaction under the reaction conditions of the present invention contains a large amount of unreacted 2-furamide and the product 2-furonitrile, and the by-product shown in the above formula is not produced in large amounts.

[0024] <Method of producing carbonate ester using 2-furonitrile> As described above, the regeneration of 2-furamide by dehydration to 2-furonitrile was achieved without the use of strong reagents, suppressing the generation of by-products and selectively obtaining the target compound in high yield. This made it possible to balance the regeneration rate of 2-furamide by dehydration to 2-furonitrile with the synthesis rate of carbonate ester from CO and alcohol using 2-furonitrile, i.e., to use them in combination, making it possible to establish a series of commercial processes for these reactions. Based on this, the present inventors applied this knowledge to the production of carbonate esters, thereby conceiving the method for producing carbonate esters described below.

[0025] (First reaction step) The first reaction step in the method for producing a carbonate ester of the present invention involves a reaction (carbonate ester production reaction) in which an alcohol is directly reacted with carbon dioxide in the presence of a solid catalyst such as CeO2, 2-furonitrile, and a solvent to produce a carbonate ester.

[0026] In this process, when alcohol and carbon dioxide are reacted, water is produced in addition to the carbonate ester. However, the presence of 2-furonitrile causes a hydration reaction with the produced water to produce 2-furoamide. Furthermore, by removing or reducing the produced water from the reaction system, it is possible to promote the production of the carbonate ester. For example, as shown in the following formula:

[0027] [ka]

[0028] (alcohol) The alcohol may be any one or more selected from primary, secondary, and tertiary alcohols. For example, methanol, ethanol, 1-propanol, isopropanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, allyl alcohol, 2-methyl-1-propanol, cyclohexanemethanol, benzyl alcohol, ethylene glycol, 1,2-propanediol, and 1,3-propanediol are preferred because they provide high product yields and fast reaction rates. The resulting carbonates are dimethyl carbonate, diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, dipentyl carbonate, dihexyl carbonate, diheptyl carbonate, dioctyl carbonate, dinonane carbonate, diallyl carbonate, di-2-methylpropyl carbonate, dicyclohexanemethyl carbonate, dibenzyl carbonate, ethylene carbonate, 1,2-propylene carbonate, and 1,3-propylene carbonate, respectively. When the resulting carbonate ester is used as a raw material for diaryl carbonate, the alcohol used is preferably one having 1 to 6 carbon atoms, more preferably one having 2 to 4 carbon atoms. It is also preferable to use a monohydric or dihydric alcohol.

[0029] (carbonate production catalyst) In the first reaction step for producing a carbonate ester, it is preferable to use a solid catalyst of either CeO2 or ZrO2, or both. For example, CeO2 alone, ZrO2 alone, a mixture of CeO2 and ZrO2, or a solid solution or composite oxide of CeO2 and ZrO2 is preferable, and the use of CeO2 alone is particularly preferable. Furthermore, the solid solution or composite oxide of CeO2 and ZrO2 basically has a CeO2 to ZrO2 mixing ratio of 50:50, but the mixing ratio can be changed as appropriate.

[0030] The solid catalyst used in the first reaction step may be in the form of either a powder or a molded body, and in the case of a molded body, it may be in any shape such as a sphere, pellet, cylinder, ring, wheel, or granule.

[0031] (carbon dioxide) The carbon dioxide used in the present invention is not only that which has been prepared as an industrial gas, but also that which has been separated and recovered from exhaust gases from factories that manufacture various products, steel mills, power plants, etc.

[0032] (Solvent in carbonate ester formation reaction) In the carbonate ester production reaction, it is preferable to use a solvent having a boiling point higher than that of the 2-furamide produced. More preferably, the solvent in the carbonate ester production reaction contains at least one of dialkylbenzene, alkylnaphthalene, and diphenylbenzene, and specific examples include barrel process oil B28AN and barrel process oil B30 (manufactured by Matsumura Oil Co., Ltd.), which contain components such as dialkylbenzene, alkylnaphthalene, and diphenylbenzene.

[0033] (Reaction solution temperature) The reaction temperature in the carbonate ester production reaction is preferably 50 to 300°C. If the reaction temperature is below 50°C, the reaction rate is low, and both the carbonate ester synthesis reaction and the hydration reaction with 2-furonitrile hardly proceed, resulting in low carbonate ester productivity. If the reaction temperature exceeds 300°C, the reaction rate of each reaction increases, but the carbonate ester is more likely to decompose or denature, and 2-furoamide is more likely to react with alcohol, resulting in a low carbonate ester yield. A more preferred temperature is 100 to 150°C. However, this temperature will likely vary depending on the type and amount of solid catalyst and the amounts and ratios of the raw materials (alcohol, 2-furonitrile), so it is desirable to set optimal conditions as appropriate. Since the preferred reaction temperature is 100 to 150°C, it is desirable to preheat the raw materials (alcohol, 2-furonitrile) with steam or the like upstream of the carbonate ester reactor.

[0034] (reaction pressure) The reaction pressure in the carbonate ester production reaction is preferably 0.1 to 20 MPa (absolute pressure). If the reaction pressure is less than 0.1 MPa (absolute pressure), a pressure reducing device is required, which not only makes the equipment complicated and costly, but also requires power energy to reduce the pressure, resulting in poor energy efficiency. If the reaction pressure exceeds 20 MPa, the hydration reaction with 2-furonitrile does not proceed easily, resulting in poor yield of carbonate ester, and requires power energy to increase the pressure, resulting in poor energy efficiency. From the viewpoint of increasing the yield of carbonate ester, the reaction pressure is more preferably 0.5 to 15 MPa (absolute pressure), and even more preferably 1.0 to 10 MPa (absolute pressure).

[0035] (2-furonitrile dosage) The 2-furonitrile used in the hydration reaction is preferably introduced into the reactor prior to the reaction in a molar amount of 0.2 to 5 times the theoretical molar amount of water by-produced in the reaction of the raw alcohol with CO2. More preferably, the molar amount of 2-furonitrile is 0.5 to 3 times, and particularly preferably 0.8 to 1.5 times, the theoretical molar amount of water by-produced in the reaction of the raw alcohol with CO2. If the molar amount of 2-furonitrile is too small, the yield of carbonate ester may be poor due to the small amount of 2-furonitrile contributing to the hydration reaction. On the other hand, introducing an excess molar amount of 2-furonitrile relative to the raw alcohol is undesirable because it increases the side reaction of 2-furonitrile. Furthermore, the amounts of alcohol and 2-furonitrile relative to the solid catalyst likely vary depending on the type and amount of the solid catalyst, the type of alcohol, and the ratio of alcohol to 2-furonitrile; therefore, it is desirable to appropriately determine optimal conditions.

[0036] (Distillation separation) After the reaction, the main product, carbonate ester, by-product, 2-furoamide, unreacted 2-furonitrile, and solid catalysts such as CeO2 are separated by distillation, and the product can be recovered.

[0037] (Second reaction step) Next, in the second reaction step of the present invention, 2-furoamide, which is a by-product of the first reaction step, is separated from the system after the carbonate ester production reaction, and then subjected to a dehydration reaction to produce 2-furonitrile. The second reaction step corresponds to the above-mentioned method for producing 2-furonitrile, and therefore details thereof will be omitted.

[0038] (Recycling of 2-furonitrile) The 2-furonitrile regenerated in the second reaction step can be reused in the first reaction step (hydration reaction). [Example]

[0039] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0040] <Gas chromatographic (GC) analysis of reaction products> The resulting reaction product was dissolved in 20 g of acetone, passed through a filter, and placed in a vial for GC analysis, followed by GC analysis. (GC and measurement conditions) GC column: Agilent Technologies CP-Sil 5 CB (length 50 m, film thickness 0.25 μm, inner diameter 0.25 mm) Inlet pressure: 100kPa Vaporization chamber temperature: 320℃ Column flow rate: 0.83 mL / min Linear speed: 19.9cm / sec Split ratio: 25.0 Total flow: 24.5mL / min Carrier gas: N2 Detector: Flame ionization detector (FID) Detector temperature: 320℃ Internal standard: Dodecane (Fujifilm Wako Pure Chemical Industries, Ltd., purity 97%) Column temperature program: (Initial) Temperature 50℃, holding time 0 minutes (1st stage) Heating rate 30℃ / min, reaching temperature 130℃, holding time 0 min (2nd stage) Heating rate 5℃ / min, reaching temperature 180℃, holding time 0 min (3 stages) Heating rate 30℃ / min, reaching temperature 300℃, holding time 10 minutes

[0041] (Supported catalyst preparation example 1) Based on the incipient-wetness method, a supported catalyst was prepared by the following procedure. In a 5 mL vial, add (NH4)6Mo7O 24 A catalyst precursor solution was prepared by precisely weighing 0.089 g of 4H2O (assay as MoO3 81%, manufactured by Wako Pure Chemical Industries, Ltd., special grade reagent, distributor 010-06905, Lot No. PTN1484) and diluting it with 3 mL of distilled water. The catalyst precursor solution was gradually added dropwise to a 100 mL beaker containing 0.96 g of SiO2 while heating and stirring. The water was then evaporated on a hot stirrer, and the mixture was then dried in an oven at 110°C for 12 hours. The resulting catalyst was placed in a muffle furnace, heated to 500°C at a rate of 10°C / min, and subsequently calcined at 500°C for 3 hours to obtain a Mo / SiO2-supported catalyst with a Mo loading of 0.5 mmol / g.

[0042] (Supported catalyst preparation example 2) (NH4)6Mo7O 24 A Cs / SiO2-supported catalyst with a Cs loading of 0.5 mmol / g was obtained in the same manner as in Preparation Example 1, except that 0.081 g of cesium carbonate (anhydrous) (standard content: 95.0-102.0% (Titration), Fujifilm Wako Pure Chemical Industries, Ltd., Wako Grade 1, distributor: 034-06542, Lot No. CAG5233) was used instead of 4H2O.

[0043] Example 1 (Dehydration of 2-furamide) A reaction tube containing a stirrer was charged with 340 mg (3 mmol) of 2-furamide (AK Scientific, Inc., purity 98.0%) as a raw material, 400 mg of the Mo / SiO2-supported catalyst obtained in Preparation Example 1, 0.1 g of dodecane (Fujifilm Wako Pure Chemical Industries, Ltd.) as an internal standard, 20 g of mesitylene as a solvent, a mesh, wool, and 2 g of molecular sieve 3A (previously calcined at 300°C for 1 hour) as a desiccant, in that order, and the tube was placed in a reactor (furnace) as shown in Figure 1, with a cooling tube attached to the top of the joint and a balloon attached to the top of the cooling tube. The reactor (furnace) was set to 180°C and 600 rpm, and the reaction was continued for 72 hours, with the reaction starting time being the time when the reaction solution began to boil. The time when the solution was removed from the reactor was defined as the reaction termination time, and the reaction product was obtained after cooling. The yield of 2-furonitrile obtained was 91%. The yield (%) of 2-furonitrile from 2-furamide was calculated by the following formula. Yield of 2-furonitrile [%] = Yield of 2-furonitrile [mmol] / Amount of raw material 2-furoamide [mmol] × 100

[0044] <Example 2> A reaction product was obtained in the same manner as in Example 1, except that 680 mg (6.0 mmol) of 2-furoamide (manufactured by AK Scientific, Inc., purity 98.0%) was used as the raw material. The yield of the obtained 2-furonitrile was 88%.

[0045] Example 3 Except for not using a drying agent (molecular sieves), a reaction product was obtained in the same manner as in Example 1. The yield of the obtained 2-furonitrile was 86%.

[0046] Example 4 Except for changing the amount of catalyst added from 400 mg to 100 mg and the reaction time from 72 hours to 24 hours, a reaction product was obtained in the same manner as in Example 1. The yield of the obtained 2-furonitrile was 57%.

[0047] <Example 5> Except for not using a drying agent (molecular sieves), a reaction product was obtained in the same manner as in Example 4. The yield of the obtained 2-furonitrile was 53%.

[0048] Example 6 Except for changing the reaction time from 72 hours to 6 hours, a reaction product was obtained in the same manner as in Example 1. The yield of the obtained 2-furonitrile was 25%.

[0049] Example 7 Except for not using a drying agent (molecular sieves), the reaction product was obtained in the same manner as in Example 6. The yield of the obtained 2-furonitrile was 17%.

[0050] <Comparative Example 1> A reaction product was obtained in the same manner as in Example 4, except that the Cs / SiO2 supported catalyst obtained in Preparation Example 2 was used as the catalyst. The yield of 2-furonitrile obtained was 38%.

[0051] <Comparative Example 2> A reaction product was obtained in the same manner as in Example 5, except that the Cs / SiO2 supported catalyst obtained in Preparation Example 2 was used as the catalyst. The yield of 2-furonitrile obtained was 27%.

[0052] <Comparative Example 3> A reaction product was obtained in the same manner as in Example 6, except that the Cs / SiO2 supported catalyst obtained in Preparation Example 2 was used as the catalyst. The yield of 2-furonitrile obtained was 14%.

[0053] <Comparative Example 4> A reaction product was obtained in the same manner as in Example 7, except that the Cs / SiO2 supported catalyst obtained in Preparation Example 2 was used as the catalyst. The yield of 2-furonitrile obtained was 16%. [Table 1]

[0054] Example 8 Cerium oxide (HSA-20SP, manufactured by Solvay Specialchem ​​Japan Co., Ltd., average particle size approximately 10 μm, impurity concentration 0.02% or less) was calcined at 600°C in an air atmosphere for 3 hours to obtain a powdered solid catalyst. Next, 0.344 g (2.0 mmol) of the above-mentioned solid catalyst, 2.33 g (25.0 mmol) of 2-furonitrile obtained in Example 1, and 0.751 g (12.5 mmol, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were placed in an autoclave (equipped with two inclined paddle stirring blades, made of SUS316, capacity 190 mL), and after CO2 replacement, the system was filled with CO2 and pressurized to 5 MPa, and a reaction (i.e., an aliphatic carbonate ester production reaction) was carried out at a reaction temperature of 132°C for 4 hours. The autoclave was then cooled, the pressure was released, and the reaction mixture was recovered. Analysis of this reaction mixture by gas chromatography revealed 7.31 g (5.0 mmol) of the target product, dipropyl carbonate (DPrC), and 0.67 g (6.0 mmol) of 2-furamide, 0.0412 g (0.04 mmol) of propyl carbamate, 0.0154 g (0.10 mmol) of propyl furan-2-carboxylate, and 0.0153 g (0.10 mmol) of propyl furan-2-imidate as by-products. Subsequently, the 2-furamide obtained as a by-product was separated, and the same procedure as in Example 1 was repeated using the 2-furamide to regenerate 2-furonitrile, which was then reused in the aliphatic carbonate ester production reaction.

Claims

1. SiO ２ Mo / SiO ２ A method for producing 2-furonitrile by dehydrating 2-furamide in the presence of a catalyst. 【Chemistry 1】

2. The method for producing 2-furonitrile according to claim 1, further comprising carrying out the dehydration in the presence of a drying agent.

3. The method for producing 2-furonitrile according to claim 2, wherein the drying agent is a molecular sieve.

4. The method for producing 2-furonitrile according to any one of claims 1 to 3, wherein 2-furocarboxylic acid is produced together with the 2-furonitrile. 【Chemistry 2】

5. a first reaction step including a carbonate ester production reaction in which an alcohol is reacted with carbon dioxide in the presence of a solid catalyst, 2-furonitrile, and a solvent to produce a carbonate ester and water, and a hydration reaction in which the produced water is hydrated with the 2-furonitrile to produce 2-furamide; After separating the 2-furamide from the reaction system of the first reaction step, the 2-furamide is treated with SiO ２ Mo / SiO ２ a second reaction step of dehydrating the 2-furonitrile in the presence of a catalyst to regenerate the 2-furonitrile; A method for producing a carbonate ester, characterized in that at least a part of the 2-furonitrile regenerated in the second reaction step is used in the first reaction step.

6. The method for producing a carbonate ester according to claim 5 , further comprising the step of carrying out the dehydration in the presence of a desiccant.

7. 7. The method for producing a carbonate ester according to claim 6, wherein the desiccant is a molecular sieve.

8. The method for producing a carbonate ester according to any one of claims 5 to 7, wherein the alcohol includes an alcohol having 1 to 6 carbon atoms.

9. The solid catalyst is CeO ２ and ZrO ２ The method for producing a carbonate ester according to any one of claims 5 to 8, comprising at least one of the following:

10. 10. The method for producing a carbonate ester according to claim 5, wherein a solvent having a boiling point higher than that of the 2-furamide produced is used in the first reaction step.

11. The method for producing a carbonate ester according to claim 10, wherein the solvent comprises at least one of a dialkylbenzene, an alkylnaphthalene, and a diphenylbenzene.

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