Method for producing cyclic urea compound

Abstract

To provide a novel technique related to the production of cyclic urea compounds.SOLUTION: Provided is a method for producing a cyclic urea compound represented by the following general formula (5) by contacting a raw material composition comprising an amine compound represented by the following general formula (1) and a carbamic acid compound represented by the following general formula (3) with a catalyst containing iron-ceria composite oxide. [In formulas (1), (3), and (5), R1 to R6 each independently denote a hydrogen atom, a phenyl group, or a C1-C4 alkyl group; n is 0 or 1.]SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] As a method for synthesizing a urea compound, for example, a method of reacting phosgene with amines can be mentioned. However, this method has a large environmental load because phosgene is highly toxic and a large amount of base is required to neutralize the by-product hydrochloric acid. Therefore, the development of a new synthesis method is an issue.

[0003] As one of the solutions to the above-mentioned problems, for example, an industrial production method for producing a cyclic urea compound by continuously supplying a mixed fluid containing the production raw materials, carbon dioxide and a diamine compound, to a metal oxide catalyst such as cerium (IV) oxide has been reported (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-187765 Summary of the Invention [Problem to be solved by the invention]

[0005] In the manufacturing method of Patent Document 1, a metal oxide catalyst (e.g., cerium (IV) oxide) is used as the catalyst, but the activity of the catalyst decreases over time, and after a certain period of time has passed since the start of production, the catalyst is no longer able to maintain sufficient catalytic activity (activity per unit surface area of ​​the catalyst).

[0006] An object of the present disclosure is to provide a novel technique for producing a cyclic urea compound. [Means for solving the problem]

[0007] As a result of extensive investigations, the present inventors have discovered a novel technique for producing a cyclic urea compound and have completed the present invention.

[0008] That is, the present disclosure includes the embodiments shown below. [1] A method for producing a cyclic urea compound represented by the following general formula (5), comprising contacting a raw material composition containing an amine compound represented by the following general formula (1) and a carbamic acid compound represented by the following general formula (3) with a catalyst containing an iron-ceria composite oxide. [ka] [In the above formulas (1), (3), and (5), R 1 ~R 6 each independently represents a hydrogen atom, a phenyl group, or an alkyl group having 1 to 4 carbon atoms. n is 0 or 1.] [2] The method according to the above [1], wherein the iron-ceria composite oxide contains 1 to 10 mol % of iron relative to 100 mol % of cerium. [3] R in the above formulas (1), (3), and (5) 1 and R 2 are each independently a hydrogen atom or a methyl group. [4] The method according to any one of [1] to [3] above, wherein n in the formulas (1), (3), and (5) is 0. [5] The method according to any one of the above [1] to [4], wherein the raw material composition is contacted with the catalyst at a temperature of 80 to 140°C. [6] The method according to any one of the above [1] to [5], wherein the catalyst further contains one or more metals selected from the group consisting of Group 3 elements, Group 4 elements, Group 7 elements, Group 9 elements, and rare earth elements. [7] The method according to any one of [1] to [6] above, wherein the catalyst further contains one or more metals selected from the group consisting of manganese, cobalt, zirconium, scandium, yttrium, lanthanum, praseodymium, neodymium, samarium, europium, gadolinium, terbium, thulium, and ytterbium. Effect of the Invention

[0009] According to the present disclosure, a novel technique for producing a cyclic urea compound can be provided. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a reaction apparatus used in a fixed bed flow reaction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The method for producing a cyclic urea compound according to the present disclosure will be described with reference to an example of the embodiment. 1 ~R 6 " is "R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 " means "R 1 ~R 4 " is "R 1 , R 2 , R 3 , and R 4 In addition, in this specification, "A to B" expressing a numerical range means "A or more and B or less," unless otherwise specified.

[0012] The present embodiment is a method for producing a cyclic urea compound represented by the following general formula (5), in which a raw material composition containing an amine compound represented by the following general formula (1) and a carbamic acid compound represented by the following general formula (3) is contacted with a catalyst containing an iron-ceria composite oxide. [ka] [In the above formulas (1), (3), and (5), R 1 ~R 6 each independently represents a hydrogen atom, a phenyl group, or an alkyl group having 1 to 4 carbon atoms. n is 0 or 1.]

[0013] Hereinafter, the amine compound represented by the above formula (1) will be referred to as "amine compound (1)", the carbamic acid compound represented by the above formula (3) will be referred to as "carbamic acid compound (3)", and the cyclic urea compound represented by the above formula (5) will be referred to as "cyclic urea compound (5)".

[0014] R in the above formulas (1), (3), and (5) 1 ~R 6 The alkyl group having 1 to 4 carbon atoms in the formula (I) is not particularly limited, but examples thereof include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and an i-butyl group.

[0015] In the above formulas (1), (3), and (5), R 1 and R 2 In terms of excellent reaction efficiency, each of the groups is preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

[0016] In the above formulas (1), (3), and (5), n is 0 or 1, but from the viewpoint of reactivity, n is preferably 0.

[0017] In addition, since the amine compound (1), the carbamic acid compound (3), and the cyclic urea compound (5) are in a relationship of a raw material and a reaction product, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 and n are R in the amine compound (1) and the carbamic acid compound (3), respectively. 1 , R 2 , R 3 , R 4 , R 5 , R 6 , and n represent the same thing.

[0018] In the above formulas (1), (3), and (5), when n is 0, the amine compound (1) is an amine compound represented by the following general formula (1'), the carbamic acid compound (3) is a carbamic acid compound represented by the following general formula (3'), and the cyclic urea compound (5) is a cyclic urea compound represented by the following general formula (5'). [ka] [In the above formulas (1'), (3', and (5'), R 1 ~R 4 is R in the above formulas (1), (3), and (5). 1 ~R 4 The same applies to the preferred ranges (preferable substituents).

[0019] The amine compound (1) is ethylenediamine represented by the following formula (A) [R 1 ~R 6 are all hydrogen atoms and n is 0. When ethylenediamine [the following formula (A)] is used as the amine compound (1), the carbamic acid compound (3) is ethylenediamine monocarbamic acid represented by the following formula (B), and 2-imidazolidinone represented by the following formula (C) is produced as the cyclic urea compound (5). [ka]

[0020] In the present embodiment, the amine compound (1) may be a commercially available product or may be one synthesized by a known method, and is not particularly limited.

[0021] In the present embodiment, the purity of the amine compound (1) is not particularly limited, but in consideration of the ease of purification in the purification step of the obtained product, the purity is preferably 95% or more, and particularly preferably 98% or more.

[0022] In the present embodiment, the carbamic acid compound (3) may be a commercially available product, or may be synthesized by reacting the amine compound (1) with carbon dioxide. The reaction conditions of the amine compound (1) with carbon dioxide are not particularly limited and may be any known conditions.

[0023] The carbon dioxide used to synthesize the carbamic acid compound (3) can be any carbon dioxide available by a generally known method, and is not particularly limited. For example, commercially available carbon dioxide gas, carbon dioxide separated from a steam reformed gas of a hydrocarbon, carbon dioxide separated from a combustion exhaust gas, or carbon dioxide obtained in a lime kiln can be used.

[0024] In this embodiment, the content of the amine compound (1) in the raw material composition is preferably 1 to 20 mol, more preferably 1.5 to 16 mol, and particularly preferably 2 to 12 mol, per 1 mol of the carbamic acid compound (3).

[0025] The raw material composition may be composed only of the amine compound (1) and the carbamic acid compound (3), or may contain water, an organic compound, or the like as components other than the amine compound (1) and the carbamic acid compound (3) (hereinafter also referred to as "other components"). The total amount of the amine compound (1) and the carbamic acid compound (3) is preferably 95% by weight or more, more preferably 99% by weight or more, and particularly preferably 100% by weight, based on 100% by weight of the raw material composition.

[0026] The raw material composition can be obtained, for example, by mixing the amine compound (1), the carbamic acid compound (3), and other components that may be included as necessary.

[0027] In this embodiment, the raw material composition described above is contacted with a catalyst containing an iron-ceria composite oxide. The form of the catalyst containing an iron-ceria composite oxide is not particularly limited, and a powdered catalyst may be used, or a catalyst formed into granules, tablets, monoliths, honeycombs, rings, or the like by spray drying, molding, sintering, or the like may be used.

[0028] The BET specific surface area of ​​the catalyst containing the iron-ceria composite oxide is not particularly limited, but from the viewpoint of promoting the reaction of synthesizing a cyclic urea compound (5) from a carbamic acid compound (3) in the presence of an amine compound (1) (hereinafter also referred to as "this reaction"), it is preferable that the BET specific surface area is 10 m 2 / g or more is preferable, and 20m 2 / g or more is more preferable, and 40m 2 The upper limit of the BET specific surface area of ​​the catalyst containing the iron-ceria composite oxide is not particularly limited, but is preferably 100 m 2 The BET specific surface area can be measured by a general nitrogen gas adsorption method, for example, by applying the BET method to the results of nitrogen gas adsorption at -196°C.

[0029] The iron-ceria composite oxide contained in the catalyst is a composite oxide containing iron, ceria, and oxygen as constituents, and is a different substance from iron-supported ceria (iron-supported ceria) which does not contain iron as a constituent component, and cerium-supported alumina (cerium-supported alumina) which does not contain cerium as a constituent component. For example, it can be identified that one of the constituents of the iron-ceria composite oxide is ceria by confirming the valence of cerium in the iron-ceria composite oxide (confirming that the valence of cerium is tetravalent). As an example, if the valence of the main cerium (e.g., 50 mol % or more of cerium) among the cerium contained in the iron-ceria composite oxide is tetravalent, it can be determined that one of the constituents of the iron-ceria composite oxide is ceria. The valence of cerium in the iron-ceria composite oxide can be confirmed by, for example, XPS or XAFS. The valence of iron in the iron-ceria composite oxide is not particularly limited, and may be divalent or trivalent, or may be in a mixed state of divalent and trivalent.

[0030] In the iron-ceria composite oxide contained in the catalyst, the iron content is not particularly limited, but is preferably 0.5 to 20 mol %, more preferably 1 to 15 mol %, and even more preferably 1 to 10 mol %, relative to 100 mol % of cerium in the iron-ceria composite oxide.

[0031] The catalyst containing the iron-ceria composite oxide may be composed only of iron, ceria, and oxygen (may be composed only of the iron-ceria composite oxide), or may contain other components different from iron, cerium, and oxygen. As the other components different from iron, cerium, and oxygen, a different metal (hereinafter also referred to as "different metal") different from iron and cerium is preferable. The different metal in the catalyst may be present in a metallic state, or may be present in the form of a compound such as an oxide.

[0032] The different metal is not particularly limited, but is preferably, for example, one or more metals selected from the group consisting of Group 3 elements, Group 4 elements, Group 7 elements, Group 9 elements, and rare earth elements, and more preferably one or more metals selected from the group consisting of manganese, cobalt, zirconium, scandium, yttrium, lanthanum, praseodymium, neodymium, samarium, europium, gadolinium, terbium, thulium, and ytterbium.

[0033] When the catalyst containing the iron-ceria composite oxide contains a different metal, the content of the different metal is preferably 0.001 to 0.5 parts by weight, more preferably 0.005 to 0.1 parts by weight, and even more preferably 0.01 to 0.05 parts by weight, per 1 part by weight of the iron-ceria composite oxide. In the catalyst containing the iron-ceria composite oxide, the total amount of the iron-ceria composite oxide and the different metal contained as necessary is preferably 95% by weight or more, more preferably 99% by weight or more, and particularly preferably 100% by weight, per 100% by weight of the catalyst.

[0034] The different metal may be contained in the catalyst as a constituent component of the iron-ceria composite oxide, or may be contained in the catalyst by being supported on the iron-ceria composite oxide.

[0035] The above catalyst may contain other components such as a binder in addition to the iron-ceria composite oxide and the different metals.

[0036] The method for producing the catalyst containing the iron-ceria composite oxide is not particularly limited, but it may be produced by a precipitation method or a complex polymerization method.

[0037] The precipitation method is not particularly limited, but a typical method is, for example, adding a base to an aqueous solution in which a cerium salt and an iron salt are mixed in an arbitrary ratio, and calcining the resulting precipitate. The calcination time for the precipitation can be, for example, 1 to 5 hours, the calcination temperature for the precipitation can be, for example, 400 to 1000°C, and the calcination atmosphere for the precipitation can be, for example, air. In the precipitation method, the precipitate obtained by adding a base to an aqueous solution in which a cerium salt and an iron salt are mixed may be filtered and / or dried by a known method before calcination.

[0038] The complex polymerization method is not particularly limited, but a typical method is, for example, to add ethylene glycol to a solution in which a citrate complex of a cerium salt and an iron salt is mixed in an arbitrary ratio, and the gel obtained by ester polymerization is baked. Note that the complex polymerization method may be performed under conditions that allow an iron-ceria composite oxide to be obtained, and may be performed under conventionally known conditions.

[0039] Examples of cerium salts that can be used in the precipitation method and complex polymerization method include cerium (III) nitrate and diammonium cerium (IV) nitrate. Examples of iron salts that can be used in the precipitation method and complex polymerization method include iron (III) nitrate.

[0040] A catalyst containing a different metal as a component of the iron-ceria composite oxide can be produced, for example, by mixing a salt of a different metal with a solution containing a cerium salt and an iron salt (their citrate complexes) in the above-mentioned precipitation method or complex polymerization method. A catalyst in which a different metal is supported on an iron-ceria composite oxide can be produced, for example, by impregnating an iron-ceria composite oxide (catalyst) obtained by the above-mentioned precipitation method or complex polymerization method with a solution containing a mixture of salts of different metals, and then calcining the resultant.

[0041] The form of this reaction is not particularly limited, but a continuous tank reaction, a batch reaction, or a fixed bed flow reaction is preferred, and a batch reaction or a fixed bed flow reaction is more preferred.

[0042] In this embodiment, the method for producing the cyclic urea compound (5) is a method for producing the cyclic urea compound (5) by contacting a raw material composition with a catalyst containing an iron-ceria composite oxide, as described above. That is, the production method of this embodiment produces the cyclic urea compound (5) by a reaction using a catalyst containing an iron-ceria composite oxide, and a known reaction apparatus used for reactions can be used.

[0043] When a fixed-bed flow-type reactor is used as a known reactor, for example, a reactor 100 can be used, as shown in FIG. 1, which includes a raw material liquid delivery pump 1 for delivering the raw material liquid, a raw material liquid tank 2 for storing the raw material liquid, a preheater 3 for heating the raw material liquid, a cylindrical fixed-bed reactor 6 equipped with a heater 4 having a catalyst layer 5 formed therein, a reaction liquid tank 7 for storing the reaction liquid discharged from the fixed-bed reactor 6, and a pipe 8 connecting these components.

[0044] For example, when a fixed-bed flow reactor is used, the flow rate (flow rate) of the raw material composition relative to the catalyst is not particularly limited, but from the viewpoints of reaction rate and economic efficiency, the amount of carbamic acid compound (3) in the raw material composition supplied to the catalyst per unit time of 1 hour is preferably adjusted to 0.1 to 10 mmol / hour, more preferably 0.1 to 5 mmol / hour, even more preferably 0.2 to 3 mmol / hour, and particularly preferably 0.5 to 2 mmol / hour, per 1 g of catalyst.

[0045] In the present embodiment, for example, when a fixed-bed flow-type reactor is used, the raw material composition is continuously supplied to the catalyst containing the iron-ceria composite oxide so that the raw material composition comes into contact with the catalyst. When the raw material composition is supplied to (comes into contact with) the catalyst, it is subjected to the catalytic action of the iron-ceria composite oxide, and a cyclic urea compound (5) is synthesized from the carbamic acid compound (3) contained in the raw material composition.

[0046] For example, when ethylenediamine monocarbamic acid (hereinafter also referred to as "EDA-CA") is used as the carbamic acid compound (3), 1 mole of 2-imidazolidinone (hereinafter also referred to as "EU") is produced from 1 mole of ethylenediamine monocarbamic acid under the catalytic action of the iron-ceria composite oxide, as shown in the following reaction formula. It is presumed that the amine compound (1) contained in the raw material composition mainly functions as a solvent for the reaction of synthesizing the cyclic urea compound (5) from the carbamic acid compound (3). [ka]

[0047] In the present embodiment, the conditions for contacting the raw material composition with the catalyst (contact temperature and pressure during contact), i.e., the reaction conditions for synthesizing the cyclic urea compound (5) from the carbamic acid compound (3) (reaction temperature, reaction pressure, etc.) are not particularly limited.

[0048] The reaction temperature (contact temperature between the raw material composition and the catalyst) is not particularly limited, but is preferably 50 to 250°C, more preferably 80 to 200°C, even more preferably 80 to 140°C, and particularly preferably 80 to 120°C, in terms of reaction rate and energy cost. The reaction temperature can be adjusted by the temperature of the catalyst and the temperature of the raw material composition that is brought into contact (supplied) with the catalyst. For example, the reaction temperature can be adjusted to a predetermined temperature by setting both the temperature of the catalyst and the temperature of the raw material composition that is brought into contact (supplied) with the catalyst to a predetermined temperature.

[0049] The reaction pressure (pressure when the raw material composition and the catalyst are in contact) is not particularly limited, but is preferably 0 to 3 MPa (gauge pressure), more preferably 0 to 1 MPa (gauge pressure), and even more preferably 0 to 0.5 MPa, in terms of reaction rate and energy cost. The gauge pressure is a pressure with atmospheric pressure set to 0 MPa.

[0050] The method for achieving the predetermined reaction pressure is not particularly limited, but the liquid phase itself may be pressurized, or a high-pressure gas may be introduced into the reaction vessel to increase the pressure.

[0051] The high-pressure gas is not particularly limited, but is preferably one or more gases selected from the group consisting of nitrogen, argon, and carbon dioxide, more preferably at least one of nitrogen and carbon dioxide, and even more preferably nitrogen. The contact between the raw material composition and the catalyst may be carried out in the presence of a gas or in the absence of a gas, regardless of the reaction pressure (even if it is below atmospheric pressure). When the contact between the raw material composition and the catalyst is carried out in the presence of a gas, the preferred gas is the same as the preferred high-pressure gas described above.

[0052] According to the production method of this embodiment described above, the catalytic activity per unit surface area (catalytic activity for catalyzing the reaction) can be maintained at a higher level even after a predetermined period of time (e.g., 7 hours or more) has elapsed since the start of the production of the cyclic urea compound (5) compared to a production method under the same conditions except for using ceria as a catalyst. Therefore, according to the production method of this embodiment, the cyclic urea compound (5) can be efficiently produced. EXAMPLES

[0053] The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In the following examples, the BET specific surface area of ​​the catalyst was determined by applying the BET method to the results of nitrogen gas adsorption at -196°C.

[0054] Preparation Example Preparation of catalyst 10% aqueous ammonia was added dropwise to an aqueous solution containing 17.38 g of cerium(III) nitrate hexahydrate, and the resulting precipitate was dried. The dried precipitate was calcined at 600°C for 3 hours in air to obtain a catalyst consisting of cerium(IV) oxide (hereafter referred to as "catalyst (CeO 2 )) Catalyst (CeO 2 The BET specific surface area of ​​43m 2 g -1 It was.

[0055] Cerium oxide (HS grade) manufactured by Daiichi Kigenso Kagaku Kogyo was dried and calcined at 600°C for 3 hours in air to obtain a catalyst made of cerium oxide (IV) (hereinafter referred to as "catalyst (CeO 2 (HS)) Catalyst (CeO 2 The BET specific surface area of ​​(HS) is 86m 2 g -1 It was.

[0056] Catalyst (CeO 2 (HS)) 5g, catalyst (CeO 2 The catalyst was dispersed in an aqueous solution of iron (III) nitrate containing 3 mol% iron relative to 100 mol% cerium in the catalyst (HS), and then dried at 100°C. The resulting solid was calcined at 600°C for 3 hours in air to obtain a catalyst made of cerium oxide carrying 3 mol% iron relative to 100 mol% cerium (hereinafter referred to as "catalyst (3Fe / CeO 2 (HS)) Catalyst (3Fe / CeO 2 The BET specific surface area of ​​(HS) is 66m 2 g -1 It was.

[0057] In an aqueous solution containing 17.38 g of cerium(III) nitrate hexahydrate, iron(III) nitrate equivalent to 1 mol% of the cerium was further dissolved, 10% aqueous ammonia was added dropwise, and the resulting precipitate was dried. The resulting solid was calcined at 600°C for 3 hours in air to obtain a catalyst consisting of an iron-ceria composite oxide containing 1 mol% iron per 100 mol% cerium (hereinafter referred to as "catalyst (1Fe-CeO 2)) Catalyst (1Fe-CeO 2 The BET specific surface area of ​​57m 2 g -1 It was.

[0058] In an aqueous solution containing 17.38 g of cerium(III) nitrate hexahydrate, iron(III) nitrate equivalent to 3 mol% of the cerium was further dissolved, 10% aqueous ammonia was added dropwise, and the resulting precipitate was dried. The resulting solid was calcined at 600°C for 3 hours in air to obtain a catalyst consisting of an iron-ceria composite oxide containing 3 mol% iron per 100 mol% cerium (hereinafter referred to as "catalyst (3Fe-CeO 2 )) Catalyst (3Fe-CeO 2 The BET specific surface area of ​​62m 2 g -1 It was.

[0059] Comparative Example 1 As shown in FIG. 1, a reaction apparatus was prepared comprising a raw material liquid tank 2, a raw material liquid delivery pump 1, a preheater 3 for heating the raw material liquid, a cylindrical fixed-bed reactor 6 equipped with a heater 4, a reaction liquid tank 7, and piping 8 connecting these.

[0060] The catalyst (CeO 2 0.5 g of ethylenediamine monocarbamic acid (CeO 2 ) was filled in the tank 2 to form a catalyst layer 5, and the catalyst layer 5 was heated to 110° C. by a heater. Next, a raw material composition consisting of ethylenediamine monocarbamic acid (9 mol %) and ethylenediamine (91 mol %) was filled in the raw material liquid tank 2, and the raw material composition was continuously sent to the fixed bed reactor 6 by using the raw material liquid sending pump 1 (in the absence of gas). Note that the raw material composition was heated to 110° C. by a preheater 3 before being sent to the fixed bed reactor 6. At this time, the catalyst (CeO 2 ) was released per unit time of one hour. 2 The amount of ethylenediamine monocarbamic acid (EDA-CA) in the raw material composition supplied to the fixed-bed reactor 6 (hereinafter also referred to as the "EDA-CA supply rate") was 6.58 [mmol / hour] per gram of catalyst. 2The pressure at the time of contact was 0 MPa (gauge pressure).

[0061] The reaction solution after passing through the fixed bed reactor 6 was analyzed, and the yield of 2-imidazolidinone (EU) was calculated. The yield of EU was calculated from the ratio of the molar amount of EU produced to the molar amount of EDA-CA used as a raw material. The analysis of the reaction solution was performed by a calibration curve method using a gas chromatograph.

[0062] The yield immediately after the start of operation (start of supply) (3 hours after the start of operation) was 16%. The yield 7 hours after the start of operation was 13%. The yield immediately after the start of operation was calculated by analyzing the reaction liquid stored in the reaction liquid tank 7 3 hours after the start of operation (the reaction liquid at the 3 hour point), and the yield 7 hours after the start of operation was calculated by analyzing the reaction liquid stored in the reaction liquid tank 7 7 hours after the start of operation (the reaction liquid at the 7 hour point). The calculated yield was divided by the BET specific surface area to determine the yield per unit surface area of ​​the catalyst (i.e., the catalytic activity per unit surface area). The yield per unit surface area of ​​the catalyst immediately after the start of operation was 0.37%, and the yield per unit surface area of ​​the catalyst 7 hours after the start of operation was 0.30%.

[0063] Comparative Example 2 In the above Comparative Example 1, the catalyst (CeO 2 ) as a catalyst (CeO 2 The reaction was carried out in the same manner as in Comparative Example 1, except that the catalyst was changed to (HS), and the yield of EU was evaluated. At this time, the EDA-CA supply rate per 1 g of catalyst was 6.58 [mmol / hour].

[0064] The yield immediately after the start of operation (start of feeding) (3 hours after the start of operation) was 30%. The yield after 7 hours from the start of operation was 24%. In addition, the yield per unit surface area of ​​the catalyst immediately after the start of operation was 0.35%, and the yield per unit surface area of ​​the catalyst after 7 hours from the start of operation was 0.28%.

[0065] Comparative Example 3 In the above Comparative Example 1, the catalyst (CeO 2 ) as a catalyst (3Fe / CeO 2 The reaction was carried out in the same manner as in Comparative Example 1, except that the catalyst was changed to (HS), and the yield of EU was evaluated. At this time, the EDA-CA supply rate per 1 g of catalyst was 6.58 [mmol / hour].

[0066] The yield immediately after the start of operation (start of feeding) (3 hours after the start of operation) was 15%. The yield after 7 hours from the start of operation was 17%. The yield per catalyst surface area immediately after the start of operation was 0.23%, and the yield per catalyst surface area after 7 hours from the start of operation was 0.26%.

[0067] Example 1 In the above Comparative Example 1, the catalyst (CeO 2 ) as catalyst (1Fe-CeO 2 ), the reaction was carried out in the same manner as in Comparative Example 1, and the yield of EU was evaluated. At this time, the EDA-CA supply rate per 1 g of catalyst was 6.58 [mmol / hour].

[0068] The yield immediately after the start of operation (start of feeding) (3 hours after the start of operation) was 25%. The yield after 7 hours from the start of operation was 22%. The yield per catalyst surface area immediately after the start of operation was 0.44%, and the yield per catalyst surface area after 7 hours from the start of operation was 0.39%.

[0069] Example 2 In the above Comparative Example 1, the catalyst (CeO 2 ) as catalyst (3Fe-CeO 2 ), the reaction was carried out in the same manner as in Comparative Example 1, and the yield of EU was evaluated. At this time, the EDA-CA supply rate per 1 g of catalyst was 6.58 [mmol / hour].

[0070] The yield immediately after the start of operation (start of feeding) (3 hours after the start of operation) was 24%. The yield after 7 hours from the start of operation was 23%. The yield per catalyst surface area immediately after the start of operation was 0.39%, and the yield per catalyst surface area after 7 hours from the start of operation was 0.37%.

[0071] The following Table 1 shows the reaction conditions, EU yield, and EU yield per unit surface area for Examples 1 and 2 and Comparative Examples 1 to 3. In the following Table 1, the initial yield refers to the yield immediately after the start of operation (3 hours after the start of operation). [Table 1] *The raw material composition was ethylenediamine monocarbamic acid (9 mol%) and ethylenediamine (91 mol%), the reaction temperature was 110°C, and the EDA-CA supply rate per 1 g of catalyst was 6.58 [mmol / h].

[0072] As shown in Table 1 above, Examples 1 and 2 had higher yields per unit surface area of ​​the catalyst immediately after the start of operation and 7 hours after the start of operation than Comparative Examples 1 to 3, which were the same except that ceria or iron-loaded ceria was used as the catalyst. From this result, it was understood that Examples 1 and 2 were able to maintain a higher catalytic activity per unit surface area of ​​the catalyst even 7 hours after the start of EU production than Comparative Examples 1 to 3. Therefore, it can be understood that EU can be efficiently produced according to the production method of this embodiment.

Claims

1. A method for producing a cyclic urea compound represented by the following general formula (5), comprising contacting a raw material composition containing an amine compound represented by the following general formula (1) and a carbamic acid compound represented by the following general formula (3) with a catalyst containing an iron-ceria composite oxide: 【Chemistry 1】 [In the above formulas (1), (3), and (5), R １ ~R ６ each independently represents a hydrogen atom, a phenyl group, or an alkyl group having 1 to 4 carbon atoms; and n is 0 or 1.

2. The method according to claim 1, wherein the iron-ceria composite oxide contains 1 to 10 mol % of iron relative to 100 mol % of cerium.

3. R in the above formulas (1), (3), and (5) １ and R ２ The method according to claim 1 , wherein each of the is independently a hydrogen atom or a methyl group.

4. The method according to claim 1, wherein n in the above formulas (1), (3), and (5) is 0.

5. The process according to claim 1, wherein the feed composition is contacted with the catalyst at a temperature of 80 to 140°C.

6. 2. The method according to claim 1, wherein the catalyst further comprises one or more metals selected from the group consisting of Group 3 elements, Group 4 elements, Group 7 elements, Group 9 elements, and rare earth elements.

7. The method according to claim 1, wherein the catalyst further comprises one or more metals selected from the group consisting of manganese, cobalt, zirconium, scandium, yttrium, lanthanum, praseodymium, neodymium, samarium, europium, gadolinium, terbium, thulium, and ytterbium.

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