Method for producing carbonic ester, and catalyst structure for producing carbonic ester

Abstract

The reaction speed of the existing catalyst in the reaction for generating carbonic ester by using carbon dioxide and monohydric alcohol is not fully improved, and higher reaction efficiency is needed. In addition, a conventional catalyst support structure used in the reaction for producing the carbonic ester has not yet a sufficiently strong structure. The above-mentioned problem is solved by a method for producing a carbonate ester. Namely, the present invention relates to a method for producing a carbonate ester, which comprises a step for producing a carbonate ester by reacting a monohydric alcohol with carbon dioxide in the presence of a catalyst structure comprising a substrate and a catalyst layer that is formed on at least a part of the surface of the substrate and that contains at least a solid catalyst and a binder, the solid catalyst contains particulate cerium oxide, and the binder contains cerium oxide as a homogeneous component.

Description

Technical Field

[0001] This invention relates to a method for manufacturing carbonates and a catalyst structure for manufacturing carbonates. Background Technology

[0002] In recent years, concern about global warming has been increasing. The international framework of agreements to reduce greenhouse gas emissions, such as the Conference of the Parties (COP), aims to control and significantly reduce peak greenhouse gas emissions as quickly as possible using the latest technologies. The Paris Agreement at COP21 (the 21st session of the Conference of the Parties) stipulates that all countries should commit to developing and proposing long-term strategies for low greenhouse gas emissions. Japan's long-term goal is to reduce greenhouse gas emissions by 80% by 2050.

[0003] It is estimated that carbon dioxide has the largest impact among anthropogenic greenhouse gases, and various regions are actively developing countermeasures and technologies to reduce it. As one such countermeasure, several attempts have been proposed to convert emitted carbon dioxide into useful substances. However, converting carbon dioxide into other substances requires significant energy and the development of effective catalysts to facilitate the reaction. Furthermore, to realize technologies that contribute to carbon dioxide reduction, it is necessary to manufacture useful products in high demand.

[0004] Carbonates are a class of compounds that are not only used as additives to increase the octane rating of gasoline and to reduce particulate matter in diesel fuel, but also as alkylating agents, carbonylating agents, and solvents in the synthesis of polycarbonates, polyurethanes, pharmaceuticals, and pesticides, as well as in the production of electrolytes for lithium batteries, lubricating oils, and deoxidizers for rust prevention in boiler pipes.

[0005] Carbonates are a general term for compounds in which one or both hydrogen atoms of carbonic acid (CO(OH)2) are replaced by alkyl or aryl groups, exhibiting a structure of RO-C(=O)-OR' (where R and R' represent saturated or unsaturated hydrocarbon groups). Therefore, if these compounds can be efficiently produced from carbon dioxide, a compound equivalent to carbonic acid, it could become an effective solution for carbon dioxide reduction.

[0006] It is known that in the process of directly synthesizing carbonates from carbon dioxide and alcohols, the reaction proceeds rapidly in the presence of a solid catalyst and a hydration agent for nitriles (see, for example, Patent Document 1). Furthermore, examples are known of using catalysts fixed in catalyst support structures and applied to solution-based reaction systems (see, for example, Patent Document 2).

[0007] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2012-162523 Patent Document 2: International Publication No. 2020 / 013135 Summary of the Invention

[0008] The problem that the invention aims to solve Even with existing catalysts used in the reaction of carbon dioxide and monohydric alcohols to form carbonates, it's difficult to say that the reaction rate has been sufficiently increased; rather, higher reaction efficiency is required. Furthermore, the existing catalyst support structures used in the carbonate formation reaction are not necessarily structurally robust enough.

[0009] Technical solutions for solving the problem During their in-depth research in order to solve the above-mentioned problems, the inventors of this invention discovered that if a binder with a set composition is used in conjunction with a catalyst, not only can the efficiency of the reaction to generate carbonate be significantly improved, but a catalyst support structure with a robust structure can also be achieved.

[0010] This invention includes the following methods for manufacturing carbonates, etc.

[0011] [1] A method for manufacturing carbonate, comprising a step of reacting a monohydric alcohol with carbon dioxide in the presence of a catalyst structure to manufacture carbonate. The catalyst structure described above includes a substrate and a catalyst layer formed on at least a portion of the surface of the substrate, which contains at least a solid catalyst and a binder. The above solid catalyst contains particulate cerium oxide. The adhesive described above contains cerium oxide as a homogeneous component.

[0012] [2] According to the method for manufacturing carbonate described in [1] above, the cerium oxide contained in the adhesive is derived from at least one of cerium compounds, namely cerium acetate, cerium sulfate and cerium nitrate.

[0013] [3] According to the method for manufacturing carbonate described in [2] above, the method for manufacturing carbonate further includes an adhesive generation step for generating the adhesive, wherein the cerium compound is calcined to obtain cerium oxide in the adhesive generation step.

[0014] [4] The method for manufacturing carbonate according to any one of [1] to [3] above, wherein the content of the cerium oxide contained in the catalyst layer as a binder is adjusted to a set range.

[0015] [4a] According to the method for manufacturing carbonate described in [2] or [3] above—for example, [2] above—the content of cerium oxide derived from the cerium compound in the catalyst layer is 1.0 to 10 by weight, based on the total weight of the catalyst layer.

[0016] [4b] A method for manufacturing carbonate according to any one of [1] to [3] above—for example, [1] above— wherein, based on the total weight of the catalyst layer, the content of the cerium oxide, which is a homogeneous component in the catalyst layer, is 1.0 to 10 by weight.

[0017] [5] A method for manufacturing carbonate according to any one of [1] to [4] above—for example, [1] above—wherein the substrate is ceramic.

[0018] [6] The method for manufacturing carbonate according to any one of [1] to [5] above—for example, [1] above—in which the loading mass of the solid catalyst in the catalyst layer is 15 g / m³. 2 Above, 200g / m 2 the following.

[0019] [7] A method for manufacturing carbonate according to any one of [1] to [6] above—for example, [1] above— wherein, in the carbonate generation reaction, a hydrating agent for removing water by-products is used.

[0020] [8] A catalyst structure for carbonate manufacturing, comprising, Substrate; and A catalyst layer formed on at least a portion of the surface of the aforementioned substrate and containing at least a solid catalyst and a binder. The above solid catalyst contains particulate cerium oxide. The adhesive described above contains cerium oxide as a homogeneous component.

[0021] [9] According to the catalyst structure for manufacturing carbonate described in [8] above, the content of the cerium oxide as a homogeneous component in the catalyst layer is 1.0 to 10 by weight, based on the total weight of the binder.

[0022]

[10] A catalyst structure for manufacturing carbonate according to [8] or [9] above—for example, [8] above— wherein the substrate is ceramic.

[0023]

[11] A catalyst structure for carbonate manufacturing according to any one of [8] to

[10] above—for example, [8] above— wherein the loading mass of the solid catalyst in the catalyst layer is 15 g / m³. 2Above, 200g / m 2 the following.

[0024]

[12] A catalyst structure for carbonate manufacturing according to any one of [8] to

[11] above—for example, [8] above— wherein the substrate has a honeycomb structure, and the pore unit density of the substrate is 15 to 200 (pores / cm²). 2 Alternatively, the wall thickness of the aforementioned substrate may be 0.01 to 2.0 mm.

[0025] [12a] According to the catalyst structure for carbonate manufacturing described in

[12] above, the pore unit density of the substrate is 15 to 200 (pores / cm²). 2 The wall thickness of the aforementioned substrate is 0.01 to 2.0 mm.

[0026] Invention Effects According to the present invention, the reaction rate of the carbonate production reaction can be increased, and carbonates can be produced efficiently. Moreover, the catalyst structure for carbonate production of the present invention has a robust structure, which can suppress catalyst pulverization and desorption even after long-term use, and maintain excellent catalytic efficiency. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a specific example of a carbonate manufacturing equipment, including various devices such as a carbonate manufacturing apparatus with a catalyst structure. Detailed Implementation

[0028] The preferred embodiments of the present invention will now be described in detail.

[0029] [1. Catalyst structure for carbonate manufacturing] First, a preferred embodiment of the catalyst structure for carbonate production of the present invention will be described. The catalyst structure for carbonate production (hereinafter also simply referred to as the "catalyst structure") is preferably used to catalyze the formation of carbonates from carbon dioxide and monohydric alcohols in the presence of a hydrating agent.

[0030] Furthermore, the catalyst structure for carbonate manufacturing in this embodiment has a substrate and a catalyst layer formed on at least a portion of the surface of the substrate, which contains a solid catalyst and a binder. The solid catalyst in the catalyst layer contains at least particulate cerium oxide. The binder in the catalyst layer contains cerium oxide as a homogeneous component. In this embodiment, the catalyst structure for carbonate manufacturing has an intermediate layer containing an inorganic binder between the catalyst layer and the substrate.

[0031] The following describes the components of the catalyst structure used in the production of carbonates.

[0032] (1.1. Substrate) The substrate is a catalyst support structure used to support a solid catalyst. By supporting the solid catalyst on the surface of the substrate, compared with using a powdered catalyst directly, it is more effective to suppress uneven distribution of the solid catalyst within the reaction vessel during the reaction process and reduce local temperature deviations within the reaction vessel caused by the generated heat of reaction. Therefore, according to this embodiment, the product carbonate can be produced with high efficiency.

[0033] Furthermore, even if the activity of the solid catalyst has decreased due to prolonged continuous reaction, it can be regenerated through heat treatment or other methods after being removed from the reaction vessel, thus restoring its function and making it easier to continue using it for an extended period. Moreover, by adjusting the composition of the solid catalyst 40, good catalytic function can be maintained for a longer time, reducing the frequency of regeneration; details will be explained later.

[0034] The substrate is not particularly limited and can be made of any material, shape, or size, as long as it can form a catalyst layer containing a solid catalyst. The substrate is particularly preferably a porous substrate with flow channels for the flow of raw material compounds such as monohydric alcohols and carbon dioxide. Because the substrate has such porous structures, not only is the diffusion efficiency of the monohydric alcohols and carbon dioxide as raw materials further improved, but the recovery of carbonates and byproducts such as water is also easier. Furthermore, by forming a catalyst layer on the surface of the porous structure, the contact area between the catalyst layer and the raw materials, monohydric alcohols and carbon dioxide, is increased, thereby improving the efficiency of the carbonate formation reaction.

[0035] The substrate shape can be, for example, porous (such as foam), corrugated, monolithic, mesh, cylindrical, or spherical. The substrate is preferably porous, foamed, honeycomb, or mesh-like. Because these shapes have interconnected pores, they effectively achieve the effects of such interconnected pores. Especially when the substrate is honeycomb-shaped, it not only provides excellent physical strength and shape stability but also results in a large specific surface area of ​​the interconnected pores.

[0036] The materials used as the constituent substrate are preferably, but not particularly limited to, various ceramic materials such as cordierite, mullite, silicon carbide, alumina, silicon oxide, titanium oxide, zirconium oxide, and cerium oxide, or metallic materials such as stainless steel and aluminum steel. Furthermore, combinations of these materials are also possible.

[0037] Furthermore, the materials of the aforementioned substrate are preferably ceramic and metal materials. Therefore, the substrate is preferably a ceramic honeycomb or a metal honeycomb, and is particularly preferably a ceramic honeycomb.

[0038] If a ceramic substrate is used, the adhesion between the catalyst layer and the substrate can be further improved. On the other hand, by using metals as the substrate material, such as stainless steel (martensitic, ferrite, austenitic, austenitic-ferrite two-phase systems, and precipitation-strengthened steel), the thermal conductivity of the substrate can be improved.

[0039] When a honeycomb structure or other component with pore units is used as the substrate, the thickness of the pore unit wall is preferably, for example, 0.01 to 2.0 mm (approximately 0.4 to 80 mil), 0.1 to 1.5 mm (approximately 4 to 60 mil), and more preferably 0.5 to 1.3 mm (approximately 2 to 50 mil). It should be noted that the ranges described in this paragraph refer to the pore unit wall thickness of the substrate. For catalyst support structures with a catalyst layer laminated on the substrate surface, the pore unit wall thickness is preferably a critical value obtained by adding the upper and lower limits of the above range to the catalyst layer thickness described later.

[0040] In addition to the aforementioned material, shape, and thickness of the cell wall, cell density is another factor that determines the structure of a substrate with pore units. Cell density is expressed as the number of pore units (cells) per unit area of ​​a cross-section orthogonal to the axis in a honeycomb structure. The preferred cell density for a honeycomb substrate is 15 to 200 pore units / cm². 2 (Approximately 200–1300 cells / inch) 2 More preferably, 20 to 150 pore cells / cm 2 (Approximately 130–970 cells / inch) 2 (More preferably, 25-120 cells / cm) 2 (Approximately 160–770 cells / inch) 2 ) or 30-100 pore cells / cm 2 (Approximately 193–645 cells / inch) 2 (Further preference is given to 45–93 cells / cm) 2 (Approximately 290–600 cells / inch) 2 ) or 62-93 pore cells / cm 2 (Approximately 400–600 cells / inch) 2 ).

[0041] (1.2. Catalyst layer) A catalyst layer is formed on at least a portion of the substrate surface. The catalyst layer has a solid catalyst containing at least particulate cerium oxide, catalyzing the reaction of carbon dioxide and monohydric alcohol to form carbonates. Such a catalyst layer is preferably formed on the inner wall surface of a connecting pore in the substrate. More preferably, the catalyst layer covers all surfaces that the raw material matrix of the reaction producing carbonates, such as carbon dioxide and monohydric alcohols, may come into contact with, such as the inner wall surface of the connecting pore.

[0042] The catalyst layer contains at least a solid catalyst and a binder. Cerium oxide, an essential component of the solid catalyst, exhibits excellent catalytic activity in the reaction of carbon dioxide and monohydric alcohol to form carbonates. On the other hand, although cerium oxide is generally prone to pulverization, in this embodiment, since it is firmly fixed to the substrate using the binder described later, desorption can be suppressed and pulverization can be prevented.

[0043] The catalyst may contain one or more catalysts other than cerium oxide. Any substance capable of catalyzing the reaction of carbon dioxide with a monohydric alcohol can be used as such a catalyst; examples include tin compounds, thallium compounds, nickel compounds, vanadium compounds, copper compounds, alkali metal carbonates, zirconium oxide, titanium oxide, and rare earth elements other than cerium (especially their oxides). Zirconium oxide is preferred due to its high catalytic activity. In this case, the proportion of cerium oxide in the solid catalyst is, for example, 5 atomic percent or more, preferably 20 atomic percent or more. Furthermore, the proportion of cerium oxide in the solid catalyst can also be 100 atomic percent.

[0044] If cerium oxide catalyst is used continuously in the direct synthesis of carbonates, the catalytic activity will decrease over time, requiring frequent catalyst regeneration. However, by adjusting the catalyst composition, high catalytic activity can be maintained. For example, when rare earth elements other than cerium are added as co-catalyst components, solid catalysts often maintain high catalytic activity for a longer period in the carbonate formation reaction.

[0045] Examples of rare earth elements other than cerium include scandium, yttrium, lanthanum, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. Lanthanum, praseodymium, and gadolinium are preferably added to the solid catalyst, with lanthanum being particularly preferred. It should be noted that these metallic elements are mainly contained in the solid catalyst in the form of oxides, or exist on the surface of the solid catalyst.

[0046] The proportion of the co-catalyst component in the solid catalyst—such as oxides of rare earth elements—is based on the total mass of the solid catalyst, preferably 0.01 to 10% by mass, more preferably 0.05 to 5.0% by mass, further preferably 0.1 to 2.5% by mass, particularly preferably 0.2 to 2.0% by mass, for example 1% by mass.

[0047] Furthermore, the loading mass of the solid catalyst in the catalyst layer, based on the unit area of ​​the catalyst layer, is preferably 15 g / m². 2 Above, 200g / m 2 The following is more preferably 20g / m 2 Above, 150g / m 2 The following is particularly preferred: 25g / m 2 Above, 100g / m 2 Below or 25g / m 2 Above, 80g / m 2 The following describes how a catalyst structure containing such a solid catalyst can improve the reaction efficiency of a catalytic reaction.

[0048] In comparison, when the loading mass of the solid catalyst is less than 15 g / m³ 2 When the catalyst structure is too large, the catalytic reaction efficiency may be insufficient. On the other hand, when the loading mass of the solid catalyst exceeds 200 g / m³, the reaction efficiency may also be insufficient. 2 At this time, it will hinder the diffusion of the raw material matrix into the depth of the catalyst layer, which may reduce the reaction efficiency.

[0049] Therefore, the loading mass of a solid catalyst and reaction efficiency are not simply positively correlated; there may be an appropriate range of solid catalyst loading masses to achieve high reaction efficiency. Catalyst structures supporting solid catalysts within this range can maintain high reactivity even at high feed rates, and further allow for relatively smaller reaction equipment. This enables equipment containing such catalyst structures to be kept at a lower cost.

[0050] From the perspective of the catalytic reaction efficiency of the catalyst structure, the loading mass of the solid catalyst in the catalyst layer is, for example, 10 g / m³. 2 Above, 200g / m 2 The preferred value is 15g / m³. 2 Above, 150g / m 2 The following is more preferably 15g / m 2 Above, 70g / m 2 The following is a further preferred value: 15g / m 2 Above, 30g / m 2 the following.

[0051] Similarly, from the perspective of the catalytic reaction efficiency of the catalyst structure, the cerium oxide loading mass in the catalyst layer is, for example, 10 g / m³. 2 Above, 200g / m 2 Below, 15g / m 2 Above, 200g / m 2The preferred value is 15g / m³. 2 Above, 150g / m 2 The following is more preferably 15g / m 2 Above, 70g / m 2 The following is a further preferred value: 15g / m 2 Above, 30g / m 2 the following.

[0052] The thickness of the catalyst layer is, for example, 12 μm to 150 μm. The catalyst layer thickness of existing products is typically less than 5 μm, making the catalyst layer in the catalyst structure of this embodiment quite thick. Previously, it was difficult to support such a large amount of solid catalyst without hindering its reactivity; however, in this embodiment, this problem is mainly solved by the binder described later. The average thickness of the catalyst layer can be between 12 μm and 180 μm, preferably between 15 μm and 150 μm, and more preferably between 30 μm and 100 μm.

[0053] Furthermore, the thickness of the catalyst layer formed in the through-holes of the substrate is usually not uniform due to the shape of the through-holes. However, when a uniform catalyst layer is formed on a plate-shaped substrate by means of a scraping method or the like, and the relationship between the amount of solid catalyst in the catalyst layer and its thickness is obtained, even when through-holes are formed, the average thickness of the catalyst layer on the substrate can be determined as the apparent thickness based on the weight of the solid catalyst it supports.

[0054] The average particle size of the particulate catalyst is, for example, but not particularly limited to, 0.001 μm or more and 100 μm or less, preferably 0.005 μm or more and 100 μm or less, more preferably 0.01 μm or more and 80 μm or less, further preferably 0.1 μm or more and 60 μm or less, particularly preferably 1.0 μm or more and 30 μm or less, and even more preferably 3.0 μm or more and 15 μm or less. This not only achieves a relatively large specific surface area of ​​the catalyst, improving the efficiency of the catalytic reaction, but also prevents the catalyst from desorbing from the binder.

[0055] In this specification, "average particle size" refers to the volumetric 50% particle size (D50) determined by wet laser diffraction scattering. However, in cases where poor dispersibility makes laser diffraction scattering measurement difficult, methods such as scanning electron microscopy, X-ray diffraction measurement, and image processing can be used.

[0056] The catalyst layer includes not only the aforementioned solid catalyst but also a binder for fixing the solid catalyst. The binder contains at least cerium oxide. The cerium oxide in the binder enables the formation of carbonates efficiently without hindering the activity of the particulate catalyst. Furthermore, by using a catalyst layer with a binder that uses cerium oxide, which is common to the catalyst, as a main component, side reactions that may occur alongside the formation of carbonates can be suppressed.

[0057] A relatively large amount of catalyst can be supported in the catalyst layer containing a binder. Furthermore, the binder allows for the robust fixation of the cerium oxide-containing solid catalyst to the substrate, suppressing desorption and peeling of the solid catalyst during the reaction. This catalyst structure with a binder-containing catalyst layer can be used for extended periods while maintaining high activity. Additionally, if an inorganic binder is used, high adhesion between the catalyst layer and the substrate can be maintained even at high reaction and regeneration temperatures without passivation.

[0058] The adhesive may also contain components other than cerium oxide, such as silicon dioxide. The type of silicon dioxide is not particularly limited; it can be silicon dioxide formed from any compound as a precursor. Furthermore, this silicon dioxide can be either amorphous or crystalline. The adhesive may also contain a certain amount of aluminum oxide, magnesium, calcium, or impurities that may be introduced during the adhesive manufacturing process. Therefore, the adhesive preferably does not contain organic compounds and can thus be called an inorganic adhesive.

[0059] Based on the total weight of the catalyst layer, the proportion of cerium oxide contained in the binder is preferably 1.0 to 10% by mass, more preferably 2.0 to 8.0% by mass or 3.0 to 7.0% by mass, and even more preferably 3.0 to 5.0% by mass. When the content of cerium oxide contained in the catalyst layer as a binder is too high, it may increase the pressure loss; while when the content is too low, the binder performance may be insufficient.

[0060] Furthermore, based on the total weight of the adhesive, the proportion of cerium oxide in the adhesive is preferably 20% by mass or more or 30% by mass, more preferably 50% by mass or more or 70% by mass, and even more preferably 80% by mass or more or 90% by mass or more. The adhesive is further preferably essentially formed of cerium oxide, and particularly preferably composed of cerium oxide.

[0061] The cerium oxide in the binder differs from that in the catalyst particles; it exists in the binder as a homogeneous component that is not visible to the naked eye. That is, it confirms that the cerium oxide forming the homogeneous component in the binder does not exist in fine particle form, but rather exists in the binder in a non-particulate state even under magnification. This is also evidenced by the fact that, for example, cerium acetate completely dissolves in water to form a homogeneous component in the binder raw material mixture used in the binder manufacturing process, as detailed later.

[0062] The specific surface area of ​​the solid component particles in the adhesive can be, for example, but is not specifically limited to, 1 m². 2 / g or more, 1000m 2 / g or less, preferably 10m 2 / g or more, 500m 2 / g or less. Because the specific surface area of ​​the binder is within the above range, it not only allows for sufficient diffusion rates of carbon dioxide and monohydric alcohol in the binder to promote the reaction on the surface of the solid catalyst, but also enables the solid catalyst to be more firmly fixed to the catalyst layer. The specific surface area can be measured by the BET method.

[0063] The loading mass of the solid component in the binder of the catalyst layer is, for example, 1 g / m³. 2 Above, 100g / m 2 The following is more preferably 1g / m 2 Above, 40g / m 2 The following is an explanation. This not only increases the exposed area of ​​the solid catalyst, thereby improving reaction efficiency, but also allows the solid catalyst to be firmly fixed to the substrate.

[0064] In the catalyst layer, the content of the solid component in the binder relative to 1g of the solid catalyst is, for example, 0.01g or more and 5g or less, preferably 0.10g or more and 1.0g or less. This not only increases the exposed area of ​​the solid catalyst, thereby improving the reaction efficiency, but also firmly fixes the solid catalyst to the substrate.

[0065] Solid components in adhesives refer to inorganic oxide particles actively introduced into the adhesive and cured adhesive residues. The mass ratio of solid components in inorganic adhesives is obtained by dividing the mass of the residue after drying and curing the inorganic adhesive by the mass of the inorganic adhesive before drying and curing. Therefore, the mass of solid components in inorganic adhesives can be calculated by multiplying the mass ratio of solid components by the mass of inorganic adhesive applied.

[0066] (1.3. Intermediate layer) An intermediate layer can also be provided between the substrate and the catalyst layer. This intermediate layer contains components that form a binder, such as cerium oxide, as described above. By forming an intermediate layer with an inorganic binder as its main component, or an intermediate layer formed of an inorganic binder, between the catalyst layer containing the solid catalyst and the substrate, the adhesion between the catalyst layer and the substrate is further improved, preventing the solid catalyst from detaching from the catalyst structure. Furthermore, due to this intermediate layer, even when using a substrate made of a material with inherently low adhesion to the catalyst layer—such as a metal substrate—sufficient adhesion between the catalyst layer and the substrate can be achieved.

[0067] Of course, in order to reliably prevent situations such as increased pressure loss, side reactions caused by components different from the catalyst, and the generation of unexpected byproducts, an intermediate layer may not be required.

[0068] Furthermore, the components of the binder in the catalyst layer and the binder forming the intermediate layer can be different or the same.

[0069] In the intermediate layer, the loading mass of the solid component in the adhesive is, for example, 1 g / m³. 2 Above, 100g / m 2 The following is more preferably 10g / m 2 Above, 50g / m 2 The following, due to the aforementioned range, not only can the agglomeration and destruction of the intermediate layer be prevented, but the adhesion between the catalyst layer and the substrate can also be further improved.

[0070] In the carbonate manufacturing catalyst structure of this embodiment described above, a relatively large amount of solid catalyst is firmly fixed to the catalyst layer using a binder containing cerium oxide. Furthermore, the binder does not hinder the catalytic reaction catalyzed by the solid catalyst. During the carbonate manufacturing process using such a carbonate manufacturing catalyst structure, the carbonate formation reaction exhibits excellent efficiency. Moreover, since the solid catalyst is firmly fixed to the substrate by an inorganic binder or the like, its desorption from the carbonate manufacturing catalyst structure can be prevented, as can the pulverization of the solid catalyst.

[0071] This catalyst structure for carbonate manufacturing achieves high reaction efficiency even in industrial processes requiring high liquid flow rates. Furthermore, by preventing desorption and pulverization of solid catalysts, it can be reused even under the harsh conditions required by industrial processes, exhibiting excellent durability.

[0072] The catalyst structure for carbonate manufacturing according to this embodiment has been described above. However, the present invention is not limited to the above embodiment.

[0073] For example, a catalyst structure for carbonate manufacturing, different from the embodiments described above, may have a catalyst layer on a substrate, omitting the intermediate layer, which is mainly composed of a binder. Even in the case where the intermediate layer is omitted, the presence of a binder such as cerium oxide ensures that the solid catalyst in the catalyst layer is sufficiently fixed, preventing its desorption from the catalyst structure for carbonate manufacturing and preventing subsequent pulverization.

[0074] It should be noted that the boundary between the catalyst layer and the intermediate layer can be observed using optical microscopes, scanning electron microscopes, and elemental analysis using EDS (energy-dispersive X-ray spectroscopy).

[0075] Furthermore, the loading mass of the solid catalyst in the catalyst layer can be calculated based on the catalyst layer area and the overall loading mass by identifying the proportion of metal components (e.g., cerium) in the catalyst layer using elemental analysis. Specifically, if the solid catalyst is composed of cerium oxide, it can be calculated using the following equation (I).

[0076] (Solid catalyst loading mass) = [(Catalyst layer mass) × (Cerium mass ratio in catalyst layer) × ((Cerium oxide mass) / (Cerium mass))] / (Catalyst layer area) ... (I) In addition, this value has the same meaning as the mass of solid catalyst per unit area of ​​the substrate where the solid catalyst is located, and this value can be obtained regardless of whether there is an intermediate layer.

[0077] As an elemental analysis method for identifying metal components, scanning high-frequency inductively coupled plasma (ICP) can be used. The loading mass of the binder in the catalyst layer and intermediate layer can also be calculated based on the metal component ratio obtained from the elemental analysis, thus determining the proportion of solid components in the binder used to form the catalyst layer, intermediate layer, etc. The catalyst layer area refers to the area where a solid catalyst (catalyst layer) is coated (formed). For example, in the case where the substrate is honeycomb-shaped and the outer periphery is not coated with a catalyst layer, the entire surface area of ​​the substrate with internal interconnecting holes and a catalyst layer is used as the catalyst layer area. The loading mass of the solid catalyst in the presence of an intermediate layer can also be calculated using the same approach.

[0078] [2. Method for manufacturing catalyst structures for carbonate production] Next, the method for manufacturing the catalyst structure for carbonate manufacturing according to this embodiment will be described.

[0079] First, a catalyst layer forming mixture is prepared for forming the substrate and the catalyst layer. The catalyst layer forming mixture can be obtained by dissolving or dispersing a solid catalyst, a cerium oxide precursor as a binder material, etc., in a suitable liquid medium, such as water or alcohol.

[0080] A catalyst layer is then formed on the surface of the substrate. Specifically, the catalyst layer can be formed by applying a catalyst layer forming mixture to the surface of the substrate, drying it, and then curing it.

[0081] The catalyst layer forming mixture can be applied by any method, such as using a bar coater, doctor blade coater, roller coater, comma coater, die coater, gravure coater, spin coater, slot coater, inkjet printer, sprayer, or immersion coater. Particularly when the substrate has through-holes, immersion is preferred; specifically, immersing the substrate in the catalyst layer forming mixture is preferable. It should be noted that to increase the film thickness of the catalyst layer, the catalyst layer forming mixture can be applied repeatedly.

[0082] When a metal or similar material is used as the substrate, and insufficient adhesion between the substrate and the catalyst layer is anticipated, it is preferable to perform the following pretreatment process before forming the catalyst layer. In the pretreatment process, for example, to remove oil from the substrate surface, the substrate is cleaned and dried using volatile organic solvents such as alcohol and acetone, and then immersed in an alkaline aqueous solution for washing and drying. Then, the substrate is immersed in an acidic aqueous solution for washing and drying. Alternatively, the substrate surface may be treated with a chemical solution, heat treatment, plasma treatment, UV treatment, or corona discharge treatment.

[0083] The drying temperature of the catalyst layer forming mixture coated on the substrate surface can be any temperature sufficient to remove the liquid medium. It can be appropriately set according to the boiling point of the medium, for example, 60°C or higher and 200°C or lower, preferably 70°C or higher and 160°C or lower, and more preferably 80°C or higher and 120°C or lower. Furthermore, the drying time can also be adjusted according to an appropriate drying state corresponding to the purpose.

[0084] The type of cerium oxide precursor contained in the mixture for forming the catalyst layer is not particularly limited, as long as it is a raw material that forms cerium oxide after the firing process described later. Specific examples of cerium oxide precursors include the following compounds: halides such as cerium chloride; inorganic salts such as cerium nitrate (cerium nitrate) and cerium sulfate; carboxylates such as cerium acetate and cerium (III) 2-ethylhexanoate; cerium hydroxide; coordination compounds (e.g., cerium triacetylacetone (cerium (III))) with ligands coordinated to cerium, such as acetoacetone and alkoxides (methanol, ethanol, tert-butoxide, etc.). Among these cerium oxide precursors, cerium sulfate, cerium nitrate, and cerium acetate are preferred from the perspective of their excellent binding effect as a binder to fix catalyst particles after firing, with cerium acetate being particularly preferred.

[0085] By using binders derived from cerium oxide precursors such as cerium acetate, side reactions caused by components different from solid catalysts—such as alumina—can be suppressed, resulting in sufficiently high efficiency of the main reaction.

[0086] In order to generate cerium oxide from the mixture used to form the catalyst layer, the mixture applied to the substrate is fired. That is, in the process of generating the binder contained in the catalyst layer, a process of firing the cerium oxide precursor contained in the mixture is performed.

[0087] The temperature of the firing process for curing the catalyst layer, represented by the adhesive, can be appropriately set according to the composition of the mixture, for example, above 200°C and below 900°C, preferably above 300°C and below 800°C, more preferably above 400°C and below 700°C or above 450°C and below 750°C, and even more preferably above 500°C and below 700°C or above 550°C and below 750°C.

[0088] In addition, the firing time can be adjusted accordingly, for example, more than 10 minutes or less than 10 hours, preferably more than 30 minutes or less than 7 hours, and more preferably more than 1 hour or less than 5 hours.

[0089] Alternatively, the mixture coated on the substrate can be dried during the firing process before firing. Drying is carried out, for example, by air supply, at a temperature of 40°C or higher and 200°C or lower, preferably 50°C or higher and 150°C or lower, more preferably 60°C or higher and 120°C or 65°C or higher and 130°C or lower. The drying temperature is further preferably 70°C or higher and 110°C or 80°C or higher and 120°C or lower.

[0090] The drying time of the mixture can also be further adjusted accordingly. For example, the drying time is more than 1 minute and less than 30 minutes, preferably more than 3 minutes and less than 20 minutes, and more preferably more than 5 minutes and less than 15 minutes.

[0091] The reaction that generates cerium oxide, for example, from a cerium acetate precursor, by means of a calcination reaction is considered to proceed according to the following schematic equation (II).

[0092] Low-humidity Ce(CH3COO)3 → High-humidity Ce(CH3COO)3 → Ce8·O3(CH3COO) 18 →CeOCH3COO→Ce2O2CO3→CeO2・・・(II) Thus, cerium oxide is generated through the main process of producing the binder, namely, the precursor thermal decomposition during calcination. The cerium oxide in the binder obtained from the calcination process differs from the cerium oxide that forms particulate catalysts; it does not have a defined shape but rather exists as a homogeneous single component within the binder. This homogeneous cerium oxide component is embedded in the gaps between the cerium particles of the catalyst and contained within the binder.

[0093] When the catalyst structure includes an intermediate layer, the following steps may be required, for example. In addition to the mixture for forming the substrate and catalyst layer described above, a binder stock solution for forming the intermediate layer must be prepared. The binder stock solution is obtained by dissolving or dispersing a binder material—such as a cerium oxide precursor—in a suitable liquid medium—such as water and alcohol. It should be noted that the concentration of the binder material in the binder stock solution is not particularly limited and can be set as appropriate depending on the method of applying the binder stock solution to the substrate.

[0094] Then, an intermediate layer is formed on the substrate before the catalyst layer is formed. Specifically, the intermediate layer can be obtained by applying the above-mentioned binder concentrate to the substrate and then drying and curing it. The application of the binder concentrate can be carried out by any method, such as using a bar coater, doctor blade coater, roller coater, comma coater, die coating, gravure coating, spin coating, slot coating, inkjet printing, spraying, dipping, etc. Especially when the substrate has through holes, dipping is preferred, and more preferably, the substrate is immersed in the binder concentrate. It should be noted that, in order to increase the film thickness of the intermediate layer, the binder concentrate can also be applied repeatedly.

[0095] The adhesive concentrate applied to the substrate is then dried and cured to form an intermediate layer. The drying conditions can be the same as those used for drying the catalyst layer forming mixture on the substrate. It should be noted that if insufficient adhesion between the substrate and the intermediate layer is expected, such as when metal is used as the substrate, a pretreatment step identical to the pretreatment step performed prior to the catalyst layer formation can be performed before forming the intermediate layer.

[0096] [3. Methods for manufacturing carbonates] Next, a method for manufacturing carbonates will be described based on a preferred embodiment. The method for manufacturing carbonates according to this embodiment includes a step of reacting a monohydric alcohol with carbon dioxide in the presence of the aforementioned catalyst structure to produce carbonates.

[0097] Before describing the method for manufacturing carbonate according to this embodiment, the mechanism of the reaction that occurs in this method will be explained. First, the catalyst layer contained in the catalyst structure catalyzes the reaction between the monohydric alcohol and carbon dioxide as shown in formula (1).

[0098] 2ROH + CO2 ⇔ (RO)2CO + H2O・・・(1) The inventors believe that the catalytic mechanism of the solid catalyst, which is the catalyst structure, is as follows: at the alkaline site, alcohols undergo dissociation and adsorption in the form of R-O-M (M is a solid catalyst), forming RO-C(=O)-O…M with CO2; on the other hand, alcohols undergo adsorption in the form of HO-R…M at the acidic site, and RO-C(=O)-OR is generated between the two adsorbed species.

[0099] The reaction shown in equation (1) above is a reversible reaction. Therefore, in the presence of byproduct water, it will react again with the generated carbonate to be reduced to a monohydric alcohol and carbon dioxide. Therefore, in order to remove the byproduct water, it is preferable to use a hydrating agent to carry out the hydration reaction shown in equation (2) below.

[0100] H2O + R'CN ⇒ R'C(=O)-NH2・・・(2) As a hydrating agent, as described below, a compound containing a cyano group as shown in formula (2) above is used.

[0101] By removing water through the reaction shown in equation (2) above, the reverse reaction in equation (1) can be suppressed, thus promoting the formation of carbonates. It should be noted that, although the reason is not yet clear, the inventors believe that the solid catalyst also has catalytic activity for the hydration reaction in equation (2) above. The mechanism of the reaction that occurs in this method has been explained above.

[0102] As described above, the method for manufacturing carbonate in this embodiment includes a step of reacting a monohydric alcohol with carbon dioxide in the presence of the catalyst structure and hydrating agent to manufacture carbonate.

[0103] Specifically, a catalyst structure is placed in the reaction vessel, and a hydrating agent, a monohydric alcohol, and carbon dioxide are introduced into the reaction vessel to carry out the carbonate reaction.

[0104] As a monohydric alcohol, one or more compounds selected from primary, secondary, and tertiary alcohols may be used.

[0105] Specifically, examples of monohydric alcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-pentanol, n-hexanol, 2-hexanol, 3-hexanol, heptanol, hexanol, phenol, etc.

[0106] The type of monohydric alcohol can be selected according to the chemical structure of the target carbonate and the method of use of the obtained carbonate.

[0107] There are no particular limitations on the hydration agent that can be selected as an optional component, as long as it can react with water to remove water. Examples include compounds containing a cyano group as shown in formula (2) above, which can be used alone or in combination of two or more. Specific examples include acetonitrile, cyanoethane, 1-cyanopropane, 2-cyanopropane, cyanoethylene, phenylacetonitrile, benzonitrile, 2-cyanopyridine, 2-cyanopyrazine, 2-cyanopyrimidine, thiophene-2-carboxynitrile, and 2-furan carboxynitrile (2-cyanofuran). In particular, from the viewpoint of water removal efficiency, i.e., the rate of hydration reaction, 2-cyanopyridine is preferred.

[0108] The amount of hydrating agent used can be set according to the amount of monohydric alcohol used. For example, the amount of hydrating agent relative to 1 mole of the monohydric alcohol used is more than 0.01 moles and less than 2 moles, preferably more than 0.1 moles and less than 0.5 moles.

[0109] The preferred, but not particularly limited, temperature for the carbonate formation reaction is 50°C or higher and 300°C or lower. Below 50°C, the reaction rate may decrease due to the type of reaction matrix, making carbonate synthesis and hydration reactions using hydrating agents almost impossible, resulting in low carbonate production. While the reaction rate increases above 300°C, the type of reaction matrix may cause carbonates and amide monomers obtained from hydration reactions to easily modify into other monomers or form polymers, thus reducing carbonate yield. A further preferred reaction temperature is 100°C or higher and 200°C or lower. However, considering that this reaction temperature varies depending on the type and amount of solid catalyst, and the amount and ratio of raw materials (monohydrin, hydrating agent), optimal conditions need to be set accordingly.

[0110] The reaction pressure is preferably, but not particularly limited to, 0.1 MPa or higher and 20 MPa or lower (absolute pressure). When the reaction pressure is below 0.1 MPa (absolute pressure), a pressure-reducing device is required, which not only increases equipment complexity and cost but also requires kinetic energy to achieve pressure reduction, potentially leading to deterioration in energy efficiency. When the reaction pressure exceeds 20 MPa, not only may the type of hydrating agent make the hydration reaction difficult to carry out, resulting in a lower carbonate yield, but the kinetic energy required for pressurization may also worsen energy efficiency. Therefore, from the perspective of improving carbonate yield, the reaction pressure is more preferably 0.1 MPa or higher and 10 MPa or lower (absolute pressure).

[0111] The reaction time is not particularly limited and can be set according to the type of reaction matrix (raw material), the type of hydrate, and the rate of byproduct formation, for example, 5 minutes or more and 24 hours or less, preferably 15 minutes or more and 8 hours or less, and more preferably 30 minutes or more and 6 hours or less. It should be noted that when using a continuous reaction apparatus, the total time from the introduction of the raw material into the reaction vessel to its discharge from the reaction vessel can be defined as the reaction time (residence time), taking into account the raw material flow rate. In addition, when the reaction matrix is ​​circulated in the catalyst structure for reaction, the circulation flow rate is defined as the spatial velocity shown in the following formula (3).

[0112] Spatial velocity (per minute) = Circulation flow rate (m³) 3 ( / minute) ÷ Volume of catalyst structure (m³) 3 )・・・(3) The space velocity is, for example, but not particularly limited to, 0.005 to 5000 per minute, preferably 0.05 to 500 per minute, and more preferably 0.5 to 50 per minute. When the space velocity is too low, the reaction efficiency may decrease due to CO2 being consumed before passing through the catalyst structure, leading to an increase in side reactions. On the other hand, a higher space velocity requires a larger pump, potentially resulting in lower energy efficiency. By circulating the reaction matrix containing the raw materials in the carbonate manufacturing apparatus at the aforementioned range, for example, a space velocity (per minute) of 0.005 to 5000, carbonates can be manufactured efficiently.

[0113] Following the above scheme, carbonates can be produced efficiently. Furthermore, since the catalyst structure of this embodiment is used, desorption and pulverization of the solid catalyst from the catalyst structure can be prevented. Therefore, the catalyst structure can be reused even under the harsh conditions required for industrial processes. Moreover, by adjusting the catalyst composition, better activity of the solid catalyst can be maintained over a longer period.

[0114] [4. Carbonate manufacturing equipment] The preferred embodiment of the carbonate manufacturing apparatus will then be described. The carbonate manufacturing apparatus includes the aforementioned catalyst structure for carbonate manufacturing. The carbonate manufacturing apparatus has, for example, a housing (outer shell). The housing is formed of, for example, an SUS tube, and the catalyst structure for carbonate manufacturing is housed inside the housing. Preferably, the carbonate manufacturing apparatus has multiple catalyst structures for carbonate manufacturing, which may, for example, be arranged in series.

[0115] The carbonate manufacturing apparatus has a feed channel that supplies monohydric alcohols and carbon dioxide, the raw materials for the production of carbonates, to the catalyst structure for carbonate manufacturing.

[0116] Once the aforementioned raw materials are supplied to the carbonate manufacturing apparatus via such a feed channel, the reaction to generate carbonate will take place inside the catalyst structure for carbonate manufacturing. Preferably, the carbonate generated by the reaction to generate carbonate, along with unreacted raw materials, is discharged to the outside of the carbonate manufacturing apparatus through a discharge channel.

[0117] To regulate the temperature of the reaction that produces carbonates, it is preferable to supply a heat transfer fluid to the carbonate manufacturing apparatus. This heat transfer fluid allows for the heating of the catalyst structure used in carbonate production and the regulation of the reaction temperature. Therefore, it is preferable that the carbonate manufacturing apparatus is equipped with a heat transfer fluid supply pipe, and the heat transfer fluid supplied to the carbonate manufacturing apparatus through the inlet of the heat transfer fluid supply pipe is discharged to the outside of the carbonate manufacturing apparatus, for example, through the outlet. Then, after the heat transfer fluid has been regulated to a set temperature, for example, it is supplied to the carbonate manufacturing apparatus again through the inlet of the heat transfer fluid supply pipe.

[0118] It should be noted that the form of the carbonate manufacturing apparatus is not limited to the apparatus described above. For example, the carbonate manufacturing apparatus may be designed to be suitable for large-scale production in order to increase the flow rate of the fluid containing raw materials supplied through the aforementioned supply channel. Thus, when the size of the carbonate manufacturing apparatus increases, sometimes an integral structure in which the catalyst structures for carbonate manufacturing are arranged in parallel and integrated together is connected in series along the height direction. In carbonate manufacturing apparatuses with this type of structure, it is easy to replace only the integral structure itself, which contains the catalyst structures that are considered to have been passivated, after long-term operation, thereby minimizing the operating costs of catalyst-related equipment. Preferably, a sealing structure is provided in the integral structure in which the catalyst structures for carbonate manufacturing are arranged in parallel and integrated together, ensuring that the fluid can pass through the catalyst structures. In addition, in order to ensure the uniformity of fluid flow within the carbonate manufacturing apparatus, it is preferable to ensure a certain amount of space at intervals when the integral structure in which the catalyst structures for carbonate manufacturing are arranged in parallel and integrated together is connected in series along the height direction. In order to minimize the apparatus by closely arranging the catalyst structures in the cross-section of the carbonate manufacturing apparatus, for example, a cuboid-shaped catalyst structure can be used. Using such a cuboid-shaped catalyst structure allows for the dense arrangement of multiple catalyst structures across the cross-section of the carbonate manufacturing apparatus, minimizing wasted storage space. However, the shape of the catalyst structure is not particularly limited; it can also be any shape other than a cuboid. Furthermore, the catalyst structure preferably has a porous, foamed, honeycomb, or sieve-like structure.

[0119] The integrated structure preferably includes a mounting plate, which serves as part of the housing, for supporting multiple catalyst structures. This mounting plate is formed, for example, a frame corresponding to the shape of the catalyst structure. The catalyst structures are preferably embedded in and detachably fixed to the frame.

[0120] Alternatively, such a catalyst structure can be replaced by adding a non-catalyst-supported cuboid honeycomb structure to a monolithic structure. This cuboid honeycomb structure without catalyst support can prevent an excess of catalyst in the carbonate manufacturing apparatus. By incorporating one or two non-catalyst-supported structures into a monolithic structure containing dozens of catalyst structures—for example, about 30 to 40 catalyst structures—the amount of catalyst distributed can be adjusted to an appropriate level, suppressing the formation of byproducts.

[0121] Furthermore, as described above, a carbonate manufacturing apparatus having a structure in which catalyst structures are arranged not only in series but also in parallel, i.e., a structure having multiple catalyst structures arranged in parallel and arranged in series as an integral structure, is suitable for a flow rate of, for example, 500 m³ / s of fluid containing raw materials. 3 / h or higher, preferably 550m 3 For reaction systems with a flow rate of 10 or more per hour, a carbonate manufacturing apparatus can be used, for example, when the supply flow rate is less than this value, by arranging only 10 or fewer catalyst structures in series.

[0122] [5. Carbonate manufacturing equipment] Next, based on a preferred embodiment, a carbonate manufacturing apparatus including the above-described carbonate manufacturing apparatus will be described. For example... Figure 1 As illustrated by an example, carbonate manufacturing equipment 100 includes, for instance, a carbonate manufacturing apparatus 60, a raw material supply system for supplying raw materials to the carbonate manufacturing apparatus 60, and a recycling system for recovering the generated carbonates.

[0123] Once the internal pressure of the CO2 storage device 72, which serves as a raw material supply system, is increased using the CO2 booster pump 73, the carbon dioxide within the CO2 storage device 72 is supplied to the buffer tank 74. Meanwhile, the raw material liquid monohydric alcohol and hydrating agents such as 2-cyanopyridine stored in the raw material tank 76 are supplied from the raw material tank 76 to the buffer tank 74 via the raw material feed pump 78. In this way, the carbon dioxide and monohydric alcohol supplied to the buffer tank 74 from different systems mix within the buffer tank 74. The mixture is then supplied to the carbonate manufacturing apparatus 60 via the first filter 80.

[0124] In the carbonate manufacturing apparatus 60, a carbonate manufacturing catalyst structure (not shown) is used to promote the reaction that produces carbonate, generating a carbonate corresponding to the type of raw material monohydric alcohol. The resulting carbonate is then supplied to a recovery system via a second filter 82. In the recovery system, the liquid containing carbonate is separated from the liquid containing unreacted raw material monohydric alcohol and hydrating agents such as 2-cyanopyridine. The liquid containing carbonate is then sent to a pumping pump 86 by a reaction liquid circulation pump 84, while the liquid containing monohydric alcohol is returned to a buffer tank 74. In the pumping pump 86, liquids other than carbonate are removed, producing a high-purity carbonate.

[0125] Example The present invention will now be described in more detail through examples and comparative examples, but the present invention is not limited to these examples and comparative examples.

[0126] <Manufacturing Example 1: Manufacturing Example of a Cerium Oxide Catalyst Structure> 700 g of cerium oxide (Solvay Special Chem Japan, HSA-20SP, CeO2 with an average particle size of approximately 10 μm), used as a catalyst, 70 g of cerium acetate hydrate (Ce(CH3CO2)3·1H2O), used as a binder, and 700 g of ion-exchanged water were added to a ball mill and pulverized for 30 minutes. 500 g of ion-exchanged water was added to the resulting pulverized material to obtain a slurry (s).

[0127] The cordierite honeycomb (ceramic honeycomb) was immersed in the above slurry (s). After confirming that the entire structure was immersed, it was lifted, blown with air, dried at 100°C, and then fired at 600°C to obtain the catalyst structure (a).

[0128] It should be noted that the ceramic honeycomb used in this example is cordierite honeycomb (ceramic honeycomb), manufactured by Nippon Kee Co., Ltd. as a ceramic carrier for catalysts (honeyceram®). The cell density of the ceramic honeycomb used is 400 cpsi (400 cells / inch). 2 = 62 cells / cm 2 The ceramic honeycomb was obtained by cutting the purchased product into a size of 40mm in diameter and 50mm in length using a core with a wall thickness of 4.5mil (114μm=0.114mm) and a core drill bit and a cutting machine.

[0129] The catalyst structure (a) was immersed again in the slurry (s). After confirming complete immersion, it was lifted, blown with air, dried at 100°C, and then fired at 600°C to obtain the catalyst structure (b1).

[0130] The resulting catalyst structure (b1) carries 5.1 g / 1 honeycomb structure, i.e., 81 g / L (loaded mass per unit volume) and 28 g / m³. 2 (The mass of particulate cerium oxide used as a catalyst per unit geometric surface area (per unit catalyst layer area))

[0131] In addition, the binder contained in the catalyst structure (b1) is formed only from cerium oxide (CeO2) derived from the raw material cerium acetate hydrate (Ce(CH3CO2)3·1H2O).

[0132] In addition, after preparing the catalyst structure using the same method as the catalyst structure (b1), a structure bearing 5.4 g / 1 honeycomb structure was also obtained, i.e., 85 g / L (loaded mass per unit volume) and 30 g / m 2 (b2) Catalyst structure of particulate cerium oxide as catalyst (mass loaded per unit geometric surface area (per unit catalyst layer area)).

[0133] <Manufacturing Example 2> In addition to replacing the ceramic honeycomb with a cell density of 600 cpsi (600 cells / inch), 2 = 93 cells / cm 2 Apart from the product of Example 1, the same procedure was performed to obtain the catalyst structure (c).

[0134] The resulting catalyst structure (c) carries 5.0 g / 1 honeycomb structure, i.e., 80 g / L (loaded mass per unit volume) and 27 g / m³. 2 (The mass of cerium oxide per unit geometric surface area) as a catalyst.

[0135] <Manufacturing Example 3> The catalyst structure (c) was immersed again in the slurry (s). After confirming complete immersion, it was lifted, blown with air, dried at 100°C, and then fired at 600°C to obtain the catalyst structure (d).

[0136] The resulting catalyst structure (d) carries 8.6 g / 1 honeycomb structure, i.e., 137 g / L (loaded mass per unit volume) and 39 g / m³. 2 (The mass of cerium oxide per unit geometric surface area) as a catalyst.

[0137] <Manufacturing Example 4> The catalyst structure (d) was immersed again in the slurry (s). After confirming complete immersion, it was lifted, blown with air, dried at 100°C, and then fired at 600°C to obtain the catalyst structure (d).

[0138] The resulting catalyst structure (e) carries 15.6 g / 1 honeycomb structure, i.e., 248 g / L (loaded mass per unit volume) and 71 g / m³. 2 (The mass of cerium oxide per unit geometric surface area) as a catalyst.

[0139] <Comparative Manufacturing Example 1: Manufacturing Example of Alumina Catalyst Structure> 700g of cerium oxide (Solvay Special Chem Japan, HSA-20SP, CeO2 powder) as a catalyst, 21g of alumina powder as a binder, and 700g of ion-exchanged water were added to a ball mill and pulverized for 30 minutes to obtain a slurry (n).

[0140] The cordierite honeycomb (ceramic honeycomb) was immersed in the above slurry (n). After confirming that the entire structure was immersed, it was lifted out, blown with air, dried at 100°C, and then fired at 600°C to obtain the catalyst structure (e).

[0141] It should be noted that the ceramic honeycomb used here is the same as that used in Manufacturing Example 1.

[0142] The catalyst structure (e) was immersed again in the slurry (n). After confirming complete immersion, it was lifted, blown with air, dried at 100°C, and then fired at 600°C to obtain the catalyst structure (f1).

[0143] The resulting catalyst structure (f1) carried 4.2 g / 1 honeycomb structure, i.e., 67 g / L (loaded mass per unit volume) and 23 g / m³. 2 (The mass of cerium oxide per unit geometric surface area) as a catalyst.

[0144] <Comparative Manufacturing Example 2> The catalyst structure (f1) was immersed again in the slurry (n). After confirming complete immersion, it was lifted, blown with air, dried at 100°C, and then fired at 600°C to obtain the catalyst structure (f2).

[0145] The resulting catalyst structure (f2) carried 8.3 g / 1 honeycomb structure, i.e., 132 g / L (loaded mass per unit volume) and 46 g / m³. 2 (The mass of cerium oxide per unit geometric surface area) as a catalyst.

[0146] <Example 1> Carbonates were manufactured using catalyst structures (b1) and (b2) obtained in Manufacturing Example 1 under the following conditions. The results are shown in Table 1.

[0147] Apparatus: Flow-through continuous reaction apparatus (refer to) Figure 1 ) Addition molar ratio: (1-Propanol (PrOH)) / (2-Cyanopyridine (2-CP)) / (Catalyst (CeO2)) = 600 / 100 / 1 Circulation flow rate: 720 mL / min Duration of stay: 4 hours Reaction pressure: 2.0 MPa Reaction temperature: 132℃ Catalyst structure: A total of 2 were used (total catalyst loading: 10.5g). <Examples 2-6, Comparative Examples 1 and 2> Except for the changes in reaction conditions shown in Table 1, the same procedure as in Example 1 was followed to produce carbonates. The results are shown in Table 1.

[0148] [Table 1] The results in Table 1 clearly confirm that in the examples where cerium oxide derived from cerium acetate was used as a binder, the yield of the target compound carbonate was high, and side reactions were suppressed. The inventors believe that such examples, by using cerium oxide as both a catalyst component and a binder, enable the main reaction utilizing only the catalyst to proceed without side reactions.

[0149] In contrast, in the comparative examples using alumina as a binder, the yield of the target carbonate was shown to be very low, and more byproducts were generated than in the examples. In the comparative examples, the alumina contained in the binder may also have acted as a secondary catalyst, triggering unexpected side reactions.

[0150] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to these specific examples. Obviously, those skilled in the art to which this invention pertains can conceive of various modifications or alterations within the scope of the technical concept described in the scope of protection claimed by the present invention, and these modifications and alterations should naturally be understood to fall within the technical scope of the present invention.

[0151] Symbol Explanation 60: Carbonate manufacturing unit 100: Carbonate manufacturing equipment

Claims

1. A method for manufacturing carbonate, wherein, This includes the process of reacting a monohydric alcohol with carbon dioxide in the presence of a catalyst structure to produce carbonates. The catalyst structure comprises a substrate and a catalyst layer formed on at least a portion of the surface of the substrate, which contains at least a solid catalyst and a binder. The solid catalyst contains particulate cerium oxide. The adhesive contains cerium oxide as a homogeneous component.

2. The method for manufacturing carbonate as described in claim 1, wherein, The cerium oxide contained in the adhesive is derived from at least one of cerium compounds: cerium acetate, cerium sulfate, and cerium nitrate.

3. The method for manufacturing carbonate as described in claim 2, wherein, It also includes an adhesive generation step for generating the adhesive, in which the cerium compound is calcined to obtain cerium oxide.

4. The method for manufacturing carbonate as described in claim 2, wherein, Based on the total weight of the catalyst layer, the content of cerium oxide derived from the cerium compound in the catalyst layer is 1.0 to 10% by weight.

5. The method for manufacturing carbonate as described in claim 1, wherein, The substrate is ceramic.

6. The method for manufacturing carbonate as described in claim 1, wherein, The solid catalyst in the catalyst layer has a loading mass of 15 g / m³. 2 Above, 200g / m 2 the following.

7. The method for manufacturing carbonate as described in claim 1, wherein, In the carbonate formation reaction, a hydrating agent is used to remove water, a byproduct.

8. A catalyst structure for carbonate manufacturing, comprising: Substrate; and A catalyst layer formed on at least a portion of the surface of the substrate and containing at least a solid catalyst and a binder. The solid catalyst comprises granular cerium oxide. The adhesive contains cerium oxide as a homogeneous component.

9. The catalyst structure for carbonate manufacturing as described in claim 8, wherein, Based on the total weight of the catalyst layer, the content of cerium oxide, which is a homogeneous component in the catalyst layer, is 1.0 to 10% by weight.

10. The catalyst structure for carbonate manufacturing as described in claim 8, wherein, The substrate is ceramic.

11. The catalyst structure for carbonate manufacturing as described in claim 8, wherein, The solid catalyst in the catalyst layer has a loading mass of 15 g / m³. 2 Above, 200g / m 2 the following.

12. The catalyst structure for carbonate manufacturing as described in claim 8, wherein, The substrate has a honeycomb structure, and the cell density of the substrate is 15-200 cells / cm². 2 Alternatively, the wall thickness of the substrate may be 0.01 to 2.0 mm.

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