KR20240084253A - The bimetallic catalyst for preparing Dimethyl Carbonate by direct conversion of Carbon Dioxide and the method for preparing Dimethyl Carbonate using thereof - Google Patents

Abstract

The present invention relates to a method for producing dimethyl carbonate through direct conversion of carbon dioxide and a catalyst thereof, and more specifically, to a catalyst containing cerium (Ce), lanthanum (La), praseodymium (Pr), samarium (Sm) and zirconium ( A cerium/transition metal (CeM) catalyst prepared by calcining a cerium/transition metal (CeM)-based metal-organic framework (CeM-BTC) further comprising one transition metal (M) selected from Zr) and such. This relates to a method of directly synthesizing dimethyl carbonate by reacting carbon dioxide and methanol using the prepared CeM catalyst.

Description

Bimetallic catalyst for preparing Dimethyl Carbonate by direct conversion of Carbon Dioxide and the method for preparing Dimethyl Carbonate using the same}

The present invention relates to a bimetallic catalyst for producing dimethyl carbonate through direct conversion of carbon dioxide and a method for producing dimethyl carbonate using the same. More specifically, it relates to a bimetallic catalyst containing cerium (Ce), lanthanum (La), praseodymium (Pr), and samarium (Sm). Cerium/transition metal (CeM) prepared by calcining a cerium/transition metal (CeM) based metal-organic framework (CeM-BTC) further comprising one transition metal (M) selected from ) and zirconium (Zr). It relates to a method of directly synthesizing dimethyl carbonate by reacting carbon dioxide and methanol using a catalyst and a cerium/transition metal (CeM) catalyst prepared as such.

Dimethylcarbonate is an environmentally friendly chemical that is not toxic to the human body and is attracting attention as its demand increases in various fields. Dimethyl carbonate has the characteristic of being able to introduce functional groups such as methyl, methoxy, and methoxycarbonyl groups into structurally different chemicals, so it is used for methylation and carbonylation in fine chemistry. It can replace highly corrosive and toxic chemicals such as dimethyl sulfate and phosgene. Moreover, dimethyl carbonate can not only replace highly toxic phosgene, methyl chloride, and dimethyl sulfate, but it is also well diluted with gasoline, has a high oxygen content, and is harmless, so it can be used as an octane number improver for automobile fuel. It is being considered as a replacement for the harmful methyl tertiarybutyl ether (MTBE). In addition, its application range is very wide as an electrolyte for secondary batteries and an intermediate for fine chemical products, and it is increasingly being applied in various fields such as high-performance resins, solvents, dye intermediates, drugs, fragrances, food preservatives, and lubricant additives.

As a process for producing dimethyl carbonate, a representative example is the phosgene method ^(1), which produces dimethyl carbonate using methanol and phosgene. However, since phosgene is a toxic substance, processes for producing dimethyl carbonate without using phosgene are being researched and developed.

COCl ₂ + 2CH ₃ OH → (CH ₃ O)2CO + 2HCl (1)

A representative process for producing dimethyl carbonate that does not use phosgene that is currently developed is the methanol oxidation method (US Patent US 5478962 A), which produces dimethyl carbonate by reacting oxygen and carbon monoxide with methanol under a copper (Ⅰ) chloride catalyst. However, this process has the disadvantages of a short lifespan of the catalyst, reactor corrosion, and the use of toxic reactants such as carbon monoxide. Additionally, water is produced as a by-product during the reaction, which requires additional energy costs to separate and purify.

Another process that does not use phosgene is the methyl nitrite method, which consists of a multi-step process (S. Uchiumi, K. Ateka, T. Matsuraki, J. Organomet. Chem. Volume 576, Page 279 (1999); T. Matsuraki, A Nakamura, Surv., Volume 1, Page 77 (1997). The methyl nitrite method produces methyl nitrite by oxidizing methanol using nitrogen dioxide in the first step, and then reacts the methyl nitrite produced in the first step with carbon monoxide under palladium catalyst conditions to produce dimethyl carbonate. As such, it has the advantage of being able to be reused in the first step by oxidizing nitrogen monoxide, which is produced as a by-product during the process, back into nitrogen dioxide, a reactant. However, this process also uses toxic carbon monoxide as a reactant, and nitrogen monoxide, one of the products, is released into the reactor. There is a problem that it corrodes.

In addition, another method for producing dimethyl carbonate is the transesterification method (US Patent US 5489703 A), which consists of a multi-step process of producing dimethyl carbonate by catalyzing ethylene oxide and carbon dioxide. Compared to the previous process, the transesterification method has the advantage that it has fewer corrosion problems in the reactor, uses cheap and less toxic raw materials, and ethylene glycol produced as a reaction by-product can be recycled into ethylene oxide, a reactant, through an appropriate chemical reaction. However, this process shows low catalytic activity and short catalyst life, and the organic solvent used in the reaction forms a triple azeotrope between methanol and dimethyl carbonate, so a lot of energy is consumed for separation and purification of dimethyl carbonate after the reaction. there is a problem.

Each of the above processes has problems such as the use of toxic reactants such as phosgene, nitrogen monoxide, and carbon monoxide, corrosion problems in the reactor, high process costs due to multi-step processes, and difficulties in separation and purification due to the production of by-products.

Due to the disadvantages of the above-described conventional methods for producing dimethyl carbonate, research and development have recently been conducted on methods for directly producing dimethyl carbonate from methanol and carbon dioxide.

The method of directly producing dimethyl carbonate from methanol and carbon dioxide is an environmentally friendly process because the process is simple, the raw materials are inexpensive, and no toxic substances are used. However, it has the disadvantage of low yield of dimethyl carbonate, and the direct production of dimethyl carbonate is difficult. Although various catalyst groups have been studied for application, a suitable catalyst system and efficient production method have not yet been proposed.

In accordance with the above circumstances, the present invention seeks to propose a new catalyst capable of directly producing dimethyl carbonate from methanol and carbon dioxide and a method for producing dimethyl carbonate using the same.

US registered patent US 5478962 A (December 26, 1995) US registered patent US 5489703 A (1996.02.06)

S. Uchiumi, K. Ateka, T. Matsuraki, J. Organomet. Chem. Volume 576, Page 279 (1999); T. Matsuraki, A. Nakamura, Catal. Surv. Jpn., Volume 1, Page 77 (1997)

The present invention was created to solve the above problems, and its purpose is to provide a catalyst for directly synthesizing dimethyl carbonate in high yield by catalyzing carbon dioxide and methanol.

Additionally, the purpose of the present invention is to provide a production method for directly synthesizing dimethyl carbonate in high yield using the catalyst.

The catalyst for synthesizing dimethyl carbonate (DMC) through the reaction of carbon dioxide and methanol according to an embodiment of the present invention includes cerium (Ce), lanthanum (La), praseodymium (Pr), samarium (Sm), and zirconium. It is a cerium/transition metal (CeM) catalyst prepared by calcining a cerium/transition metal (CeM)-based metal-organic framework (CeM-BTC) further containing one transition metal (M) selected from (Zr). It is characterized by

Additionally, as an example, the calcination temperature of the catalyst is characterized in that it is in the range of 350 to 800°C.

In addition, a method for producing a catalyst for producing dimethyl carbonate through direct conversion of carbon dioxide according to another embodiment of the present invention includes the steps of (a) dissolving a precursor solution of BTC ligand to obtain a BTC ligand solution; (b) dissolving a cerium precursor and a transition metal (M) precursor selected from lanthanum, praseodymium, samarium, and zirconium to obtain a cerium + transition metal (M) precursor solution; (c) mixing and stirring the BTC ligand solution and the cerium + transition metal (M) precursor solution to synthesize a CeM-BTC metal-organic framework; (d) filtering and washing the solution containing the synthesized CeM-BTC; And (e) drying and calcining the CeM-BTC collected after filtration to convert it into cerium-transition metal (CeM).

In addition, as an example, the solvent is characterized in that it is one or more selected from water (H ₂ O), ethanol (EtOH), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and acetonitrile. .

Additionally, in one embodiment, the cerium precursor is characterized in that it is at least one selected from the group consisting of cerium nitrate, cerium carbonate, cerium acetate, cerium halide salt, and cerium chloride.

In addition, as an example, the lanthanum precursor is at least one selected from the group consisting of nitrate hexahydrate and lanthanum chloride heptahexahydrate, and the praseodymium precursor is at least one selected from the group consisting of praseodymium nitrate hexahydrate. The samarium precursor is at least one selected from the group consisting of samarium nitrate hexahydrate, and the zirconium precursor is one selected from the group consisting of zirconyl oxynitrate hydrate, zirconyl oxychloride octahydrate, and zirconium chloride. It is characterized by the above.

In addition, in one embodiment, the execution order of steps (a) and (b) is independent, and one of steps (a) and (b) may be performed before the other step, and the two steps may be performed independently. It is characterized in that it can be performed simultaneously.

Additionally, as an example, in step (b), the cerium precursor and the transition metal (M) precursor are mixed at a molar mass ratio of 5:95 to 95:5.

In addition, as an example, in step (b), the cerium precursor and the transition metal (M) precursor are separately dissolved in a solvent to prepare a cerium precursor solution and a transition metal (M) precursor solution, and in step (c), the cerium precursor solution and the transition metal (M) precursor solution are prepared separately. When mixing the solutions obtained in steps (a) and (b), the CeM-BTC metal-organic framework is synthesized by simultaneously mixing the BTC ligand solution, the cerium precursor solution, and the transition metal (M) precursor solution, or First, the BTC ligand solution is mixed with either the cerium precursor solution or the transition metal (M) precursor solution to synthesize the Ce-BTC metal-organic framework or the M-BTC metal-organic framework, and then the remaining precursors are added. It is characterized by synthesizing the CeM-BTC metal-organic framework by mixing solutions.

Additionally, as an example, the temperature in step (c) is characterized as 50 to 120°C.

Additionally, as an example, the sintering temperature in step (e) is characterized in that it is 350 to 800°C.

In addition, the method for producing dimethyl carbonate through direct conversion of carbon dioxide according to another embodiment of the present invention includes cerium (Ce), lanthanum (La), praseodymium (Pr), samarium (Sm), and zirconium (Zr). ) carbon dioxide and It is characterized in that it includes; reacting methanol.

In addition, as an example, the amount of catalyst used in the method for producing dimethyl carbonate is 0.1 to 100 parts by weight based on 100 parts by weight of methanol.

In addition, as an example, the method for producing dimethyl carbonate is characterized by carrying out a catalytic reaction under conditions of a temperature range of 50 to 250 ° C. and a pressure range of 1 to 200 bar.

The present invention involves directly synthesizing dimethyl carbonate by catalyzing carbon dioxide and methanol, including cerium (Ce) as the catalyst, and lanthanum (La), praseodymium (Pr), samarium (Sm), and zirconium (Zr). By using a cerium/transition metal (CeM) catalyst prepared by calcining a cerium/transition metal (CeM) based metal-organic framework (CeM-BTC) further comprising one selected transition metal (M), It has the effect of directly synthesizing dimethyl carbonate from methanol in high yield.

Figure 1 shows the dimethyl carbonate yield when using the catalyst according to Examples 1 to 4 and Comparative Examples 1 to 2 of the present invention in producing dimethyl carbonate by catalyzing carbon dioxide and methanol.

Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by a person skilled in the art to which the present invention pertains. In general, the nomenclature used herein is well known and commonly used in the art.

Throughout this specification, when a part “includes” a certain component, this means that it may further include other components rather than excluding other components, unless specifically stated to the contrary.

Additionally, when explaining in detail the principles of a preferred embodiment of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description will be omitted.

The present invention relates to a catalyst for producing dimethyl carbonate through direct conversion of carbon dioxide and a method for producing dimethyl carbonate using the same, and to a catalyst for directly synthesizing dimethyl carbonate in high yield by catalytic reaction of carbon dioxide and methanol and a method for producing dimethyl carbonate using the same. will be.

Specifically, the present invention uses a method of catalytic reaction between carbon dioxide and methanol to produce dimethyl carbonate in high yield through a single process, including cerium (Ce) as a reaction catalyst, lanthanum (La), and praseodymium. prepared by firing a cerium/transition metal (CeM) based metal-organic framework (CeM-BTC) further comprising one transition metal (M) selected from (Pr), samarium (Sm), and zirconium (Zr). A method for producing dimethyl carbonate using a cerium/transition metal (CeM) catalyst is provided.

The CeM-BTC is one of the metal-organic frameworks. The central metals are Ce and M (La, Pr, Sm, Zr), and the ligand is BTC (trimesic acid), forming a metal-organic framework. .

The present invention is to produce DMC by promoting the reaction of carbon dioxide and methanol using a cerium/transition metal (CeM) catalyst prepared by firing the cerium/transition metal (CeM)-based metal-organic framework (CeM-BTC). It is characterized by

The method for producing the carbon dioxide conversion dimethyl carbonate production catalyst according to the present invention includes the steps of (a) dissolving the precursor solution of the BTC ligand to obtain a BTC ligand solution; (b) dissolving a cerium precursor and a transition metal (M) precursor selected from lanthanum, praseodymium, samarium, and zirconium to obtain a cerium + transition metal (M) precursor solution; (c) mixing and stirring the BTC ligand solution and the cerium + transition metal (M) precursor solution to synthesize a CeM-BTC metal-organic framework; (d) filtering and washing the solution containing the synthesized CeM-BTC; and (e) drying and calcining the CeM-BTC collected after filtration to convert it into a CeM-BTC-based transition metal (CeM) catalyst.

In step (a), trimesic acid, also known as Benzene-1,3,5-tricarboxylic acid, is used as the BTC precursor solution.

The concentration of the BTC precursor solution may be 0.06 to 0.5 mol/L, and when it is within this range, the synthesis efficiency of Ce-BTC is high.

Step (b) is a step of obtaining a precursor solution of cerium, lanthanum, praseodymium, samarium or zirconium, wherein the cerium precursors include cerium nitrate, cerium carbonate, cerium acetate, cerium halide, cerium chloride, etc. It may be one or more selected from, and the precursor of lanthanum includes lanthanum nitrate hexahydrate (La(NO ₃ ) ₃ 6H ₂ O) and lanthanum chloride heptahexahydrate (LaCl ₃ ·7H ₂ O), etc. may be at least one selected from the group consisting of, and the precursor of the praseodymium may be at least one selected from the group consisting of praseodymium nitrate hexahydrate (Sm(NO ₃ ) ₃ ·6H ₂ O), etc. The samarium precursor may be one or more selected from the group consisting of samarium nitrate hexahydrate (Sm(NO ₃ ) ₃ ·6H ₂ O), and the zirconium precursor may include zirconyl oxynitrate. In the group consisting of hydrate (zirconyl oxynitrate hydrate, ZrO(NO ₃ ) ₂ ·xH ₂ O), zirconyl oxychloride octahydrate (ZrOCl ₂ ·8H ₂ O), zirconium chloride (ZrCl ₄ ), etc. There may be more than one selected.

Additionally, when preparing the cerium + transition metal (M) precursor solution in step (b), the cerium precursor and the transition metal (M) precursor are mixed at a molar mass ratio of 5:95 to 95:5. Preferably, when preparing a CeM catalyst, each metal precursor is mixed so that the Ce:M molar ratio is 50:50 to 95:5, and more preferably, each metal precursor is mixed so that the Ce:M molar ratio is 80:20 to 90:10. Mix, and most preferably, mix each metal precursor in a ratio of 85:15.

The solvent in steps (a) and (b) is one or more selected from water (H ₂ O), ethanol (EtOH), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), acetonitrile, etc. It can be included.

Although the steps (a) and (b) are described sequentially, the order is not important, and the order of performance of steps (a) and (b) is independent. One step may be performed before the other step, or two steps may be performed simultaneously.

Step (c) is a step of mixing the solutions obtained in steps (a) and (b). Mixing can be accomplished through an appropriate stirring means such as a magnetic bar or stirrer, and the temperature in step (c) is It may range from 50 to 120°C.

For reference, in step (b), a cerium + transition metal (M) precursor solution may be prepared by dissolving the cerium precursor and the transition metal (M) precursor together in a solvent, or the cerium precursor and the transition metal (M) precursor may be dissolved together in a solvent. A cerium precursor solution and a transition metal (M) precursor solution may be prepared by separately dissolving them in a solvent.

As described above, when preparing the cerium precursor solution and the transition metal (M) precursor solution in step (b), the BTC ligand is mixed in step (c) by mixing the solutions obtained in steps (a) and (b). The CeM-BTC metal-organic framework can be synthesized by mixing a solution, a cerium precursor solution, and a transition metal (M) precursor solution. First, the BTC ligand solution is mixed with either the cerium precursor solution or the transition metal (M) precursor solution. After synthesizing the Ce-BTC metal-organic framework or M-BTC metal-organic framework by mixing one solution, the CeM-BTC metal-organic framework can also be synthesized by additionally mixing the remaining precursor solutions. there is.

Filtration in step (d) may be performed using a conventional filtration means such as a filter, and washing may be repeated several times.

Step (e) is a process to sinter the formed CeM-BTC to remove the BTC ligand and obtain a cerium-transition metal (CeM) form, and the sintering may be performed in the range of 350 to 800°C. The atmosphere gas used during the firing is not limited to air or inert gas, but it is preferable from an economical point of view to carry out the firing in air.

As described above, the CeM-BTC-based cerium/transition metal (CeM) catalyst has a relatively high specific surface area compared to cerium oxide (CeO ₂ ) produced from Ce-BTC, and is active for the conversion of carbon dioxide into dimethyl carbonate. It is highly effective.

A method for producing dimethyl carbonate through direct conversion of carbon dioxide according to another embodiment of the present invention includes the step of reacting methanol and carbon dioxide in the presence of a CeM-BTC-based cerium/transition metal (CeM) catalyst prepared as described above. Includes.

The method for producing dimethyl carbonate through direct conversion of carbon dioxide according to the present invention can be performed in a batch reactor and does not require a separate solvent because methanol is used in a liquid phase.

In the step of reacting methanol and carbon dioxide, the reaction temperature as reaction conditions is preferably 50 to 250°C, and more preferably 80 to 180°C.

By setting the reaction temperature above 50°C, high activation of the catalyst for the reaction can be secured, and by setting the reaction temperature below 250°C, the problem of yield reduction due to thermodynamic equilibrium conversion rate limitations can be prevented.

In addition, in the step of reacting methanol and carbon dioxide, the reaction pressure as reaction conditions is preferably 1 to 200 bar, and more preferably 5 to 100 bar.

By setting the reaction pressure to 1 bar or more, it is possible to prevent a decrease in the yield of dimethyl carbonate due to the thermodynamic equilibrium conversion rate limit, and by setting the reaction pressure to less than 200 bar, the stability and efficiency of reaction process operation can be ensured.

Additionally, in the step of reacting methanol and carbon dioxide, it is preferable to carry out appropriate stirring in terms of reaction efficiency.

In addition, in the step of reacting methanol and carbon dioxide, the reaction catalyst uses a CeM-BTC-based cerium/transition metal (CeM) catalyst prepared according to an embodiment of the present invention, and the catalyst is methanol introduced as a reactant. It is preferable to use it in an amount of 0.1 to 100 parts by weight, and more preferably in an amount of 1 to 10 parts by weight, based on 100 parts by weight.

If the amount of catalyst used is less than 1 part by weight, reaction efficiency may be reduced or the reaction rate may be significantly lowered, and if it exceeds 100 parts by weight, it results in using more catalyst than necessary, making it uneconomical.

The method for producing dimethyl carbonate through direct conversion of carbon dioxide according to the present invention can achieve maximum dimethyl carbonate yield when performed within the temperature, pressure, stirring speed, and catalyst amount ranges as described above.

Hereinafter, the method for producing dimethyl carbonate through direct conversion of carbon dioxide according to the present invention will be described in detail through examples and comparative examples.

The present invention includes cerium (Ce) as a reaction catalyst between carbon dioxide and methanol, and further includes one transition metal (M) selected from lanthanum (La), praseodymium (Pr), samarium (Sm), and zirconium (Zr). The production yield of dimethyl carbonate is increased by using cerium/transition metal (CeM) produced by firing a cerium/transition metal (CeM)-based metal-organic framework (CeM-BTC). In the examples below, CeM-BTC is used to increase the production yield of dimethyl carbonate. We aim to explain the excellent effectiveness of BTC-based cerium/transition metal (CeM) catalyst.

More specifically, in the following Examples and Comparative Examples, when dimethyl carbonate was synthesized by catalyzing carbon dioxide and methanol, the yield of dimethyl carbonate when using the catalyst prepared in each Example and Comparative Example was compared.

<Example 1>

CeLa catalyst

Prepare a mixed solution by stirring 200 ml of distilled water and 200 ml of ethanol in a 2L round bottom flask. Add 42 g of 1,3,5-benzenetrimethylcarboxylic acid to the prepared mixed solution and stir, then raise the temperature to 70°C to form 1,3,5-benzenetrimethylcarboxylic acid. It was confirmed that the boxylic acid was completely dissolved (solution 1). Separately from Solution 1, Solution 2 is prepared by dissolving 73.8 g of cerium nitrate hexahydrate and 13.0 g of lanthanum nitrate hexahydrate in 900 ml of distilled water.

Solution 2 is poured into solution 1 stirred at 70°C for 2 minutes, and stirred at 70°C for 5 hours to synthesize CeLa-BTC.

After the stirring was completed, CeLa-BTC was filtered using a reduced pressure filtration device. The synthesized Ce-BTC was washed with ethanol three times, and each ethanol wash was carried out by dispersing CeLa-BTC in 1500 ml of ethanol, stirring for more than 6 hours, and then filtering. The washed Ce-BTC was dried at 110°C for more than 12 hours using a drying oven.

To synthesize CeLa-BTC, a synthesized metal organic framework (MOF), into a metal oxide, the temperature is raised from room temperature to 350°C at a rate of 2°C/min in a muffle electric furnace, and then fired at 350°C for 5 hours. went through Through the firing process, 1,3,5-benzenetrimethylcarboxylic acid in CeLa-BTC is thermally decomposed and disappears, converting to CeLa form.

<Example 2>

CePr catalyst

Separately from solution 1, solution 2 was prepared by dissolving 73.8 g of cerium nitrate hexahydrate and 13.06 g of praseodymium nitrate hexahydrate in 900 ml of distilled water. The same method as Example 1. A CePr catalyst was prepared.

<Example 3>

CeSm catalyst

The same method as Example 1, except that Solution 2 was prepared by dissolving 73.8 g of cerium nitrate hexahydrate and 13.34 g of samarium nitrate hexahydrate in 900 ml of distilled water separately from Solution 1. A CeSm catalyst was prepared.

<Example 4>

CeZr catalyst

Separately from Solution 1, Solution 2 was prepared by dissolving 73.8 g of cerium nitrate hexahydrate and 13.34 g of zirconium nitrate hexahydrate in 900 ml of distilled water. A CeZr catalyst was prepared.

<Comparative Example 1>

CeO ₂ catalyst

Prepare a mixed solution by stirring 200 ml of distilled water and 200 ml of ethanol in a 2L round bottom flask. Add 42 g of 1,3,5-benzenetrimethylcarboxylic acid to the prepared mixed solution and stir, then raise the temperature to 70°C to form 1,3,5-benzenetrimethylcarboxylic acid. It was confirmed that the boxylic acid was completely dissolved (solution 1). Separately from Solution 1, Solution 2 is prepared by dissolving 86.8 g of Cerium nitrate hexahydrate in 900 ml of distilled water.

Solution 2 is poured into solution 1 stirred at 70°C for 2 minutes, and stirred at 70°C for 5 hours to synthesize Ce-BTC.

After the stirring was completed, Ce-BTC was filtered using a reduced pressure filtration device. The synthesized Ce-BTC was washed with ethanol three times, and each ethanol wash was carried out by dispersing Ce-BTC in 1500 ml of ethanol, stirring for more than 6 hours, and then filtering. The washed Ce-BTC was dried at 110°C for more than 12 hours using a drying oven.

To synthesize Ce-BTC, a synthesized metal organic framework (MOF), into a metal oxide, the temperature is raised from room temperature to 350°C at a rate of 2°C/min in a muffle electric furnace, and then fired at 350°C for 5 hours. went through Through the firing process, 1,3,5-benzenetrimethylcarboxylic acid in Ce-BTC is thermally decomposed and disappears, converting to ceria (CeO ₂ ).

<Comparative Example 2>

Ru/CeO ₂

Using the CeO ₂ prepared in Comparative Example 1 as a support, 3 g of ruthenium chloride (RuCl ₃ ·xH ₂ O) was supported on the CeO ₂ support according to an impregnation method using a solution dissolved in 5 ml of distilled water. The result was dried in a drying oven at 110 ^o C for more than 12 hours to remove moisture, and then calcined in a muffle electric furnace at 350 ^o C for 4 hours to prepare the final catalyst.

<Experimental Example 1>

Direct synthesis of dimethyl carbonate using methanol and carbon dioxide was performed as follows using the catalyst prepared or prepared according to Examples 1 to 4 and Comparative Examples 1 and 2.

To carry out the reaction, a 3/8 inch fixed bed reactor was used as the reactor. The temperature inside the reactor represents the temperature measured after inserting a thermocouple 1/16 inch from the top of the reactor into the reactor and adjusting the length to be located at the top of the catalyst layer. A 1/4 inch pipe was installed at the bottom of the reactor and 2 g of catalyst was charged to perform a reaction according to an example. At this time, heat was supplied to the reactor through an electric furnace, and the temperature of the reactor was controlled from outside the reactor using a PID controller using a thermocouple outside the electric furnace. While increasing the temperature of the reactor from room temperature to the reaction temperature of 120°C, only carbon dioxide was injected and flowed. Then, after isothermal conditions in which the reaction temperature of the present invention of 120°C is maintained and a reaction pressure of 10 bar are formed, 18ul of methanol is injected into the reaction interior through an HPLC pump to vaporize it, and the carbon dioxide flow rate is changed to 50 ml. The reaction proceeded. Analysis of the produced gas was confirmed through gas chromatography (GC Chromatography) connected to the reactor, and a thermal conductivity detector (TCD) and a flame ionization detector (FID) were used as detectors. The results of the catalytic activity of dimethyl carbonate, etc. produced through a direct reaction of carbon dioxide through the reaction according to the above example are shown in Figure 1.

As shown in Figure 1, compared to CeO ₂ prepared by calcining the cerium-based metal-organic framework (Ce-BTC) and the conventional Ru/CeO ₂ catalyst, the cerium/transition metal (CeM)-based metal-organic framework (CeM) When using cerium/transition metal (CeM) catalysts (CeLa, CePr, CeSm, and CeZr) prepared by calcination of -BTC), the yield of dimethyl carbonate was found to be improved.

The present invention has been described above with reference to the embodiments shown in the attached drawings, but these are merely illustrative, and various modifications and other equivalent embodiments can be made by those skilled in the art. You will understand that Therefore, the scope of technical protection of the present invention should be determined by the scope of the patent claims below.

Claims (14)

In the catalyst for synthesizing dimethyl carbonate (DMC) through the reaction of carbon dioxide and methanol,
The catalyst contains cerium (Ce) and further contains one transition metal (M) selected from lanthanum (La), praseodymium (Pr), samarium (Sm), and zirconium (Zr). Cerium/transition metal (CeM) ) A catalyst for the production of dimethyl carbonate through direct conversion of carbon dioxide, characterized in that it is a cerium/transition metal (CeM) catalyst prepared by calcining a based metal-organic framework (CeM-BTC).
According to paragraph 1,
A catalyst for the production of dimethyl carbonate through direct conversion of carbon dioxide, characterized in that the calcination temperature of the catalyst is in the range of 350 to 800 ° C.
(a) dissolving the precursor solution of the BTC ligand in a solvent to obtain a BTC ligand solution;
(b) dissolving a cerium precursor and a transition metal (M) precursor selected from lanthanum, praseodymium, samarium, and zirconium in a solvent to obtain a cerium + transition metal (M) precursor solution;
(c) mixing and stirring the BTC ligand solution and the cerium + transition metal (M) precursor solution to synthesize a CeM-BTC metal-organic framework;
(d) filtering and washing the solution containing the synthesized CeM-BTC; and
(e) drying and calcining the CeM-BTC collected after filtration to convert it into cerium-transition metal (CeM); a method for producing a catalyst for the production of dimethyl carbonate through direct conversion of carbon dioxide, comprising:
According to paragraph 3,
In the reaction between carbon dioxide and methanol, the solvent is characterized in that one or more selected from water (H ₂ O), ethanol (EtOH), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and acetonitrile. Method for producing a catalyst for producing dimethyl carbonate.
According to paragraph 3,
A method for producing a catalyst for producing dimethyl carbonate by the reaction of carbon dioxide and methanol, wherein the cerium precursor is at least one selected from the group consisting of cerium nitrate, cerium carbonate, cerium acetate, cerium halide salt, and cerium chloride.
According to paragraph 3,
The lanthanum precursor is at least one selected from the group consisting of nitrate hexahydrate and lanthanum chloride heptahexahydrate, the praseodymium precursor is at least one selected from the group consisting of praseodymium nitrate hexahydrate, and the samarium precursor is is at least one selected from the group consisting of samarium nitrate hexahydrate, and the precursor of the zirconium is carbon dioxide, characterized in that at least one selected from the group consisting of zirconyl oxynitrate hydrate, zirconyl oxychloride octahydrate, and zirconium chloride. Method for producing a catalyst for producing dimethyl carbonate by reaction of methanol.
According to paragraph 3,
The execution order of steps (a) and (b) is independent, and one of steps (a) and (b) may be performed before the other step, and the two steps may be performed simultaneously. Characterized by a method for producing a catalyst for producing dimethyl carbonate by the reaction of carbon dioxide and methanol.
According to paragraph 3,
A method for producing a catalyst for producing dimethyl carbonate by the reaction of carbon dioxide and methanol, characterized in that in step (b), the cerium precursor and the transition metal (M) precursor are mixed at a molar mass ratio of 5:95 to 95:5.
According to paragraph 3,
In step (b), the cerium precursor and the transition metal (M) precursor are separately dissolved in a solvent to prepare a cerium precursor solution and a transition metal (M) precursor solution, respectively.
In step (c), when mixing the solutions obtained in steps (a) and (b), the BTC ligand solution, the cerium precursor solution, and the transition metal (M) precursor solution are mixed simultaneously to form a CeM-BTC metal-organic frame. Synthesize the work, or first mix the BTC ligand solution with either a cerium precursor solution or a transition metal (M) precursor solution to synthesize the Ce-BTC metal-organic framework or the M-BTC metal-organic framework. , A method for producing a catalyst for producing dimethyl carbonate by the reaction of carbon dioxide and methanol, characterized in that the CeM-BTC metal-organic framework is synthesized by mixing the remaining precursor solution.
According to paragraph 3,
A method for producing a catalyst for producing dimethyl carbonate by the reaction of carbon dioxide and methanol, characterized in that the temperature in step (c) is 50 to 120 ° C.
According to paragraph 3,
A method for producing a catalyst for dimethyl carbonate synthesis by the reaction of carbon dioxide and methanol, characterized in that the calcination temperature in step (e) is 350 to 800°C.
A cerium/transition metal (CeM)-based metal comprising cerium (Ce) and further comprising one transition metal (M) selected from lanthanum (La), praseodymium (Pr), samarium (Sm), and zirconium (Zr). -A method for producing dimethyl carbonate through direct conversion of carbon dioxide, comprising the step of reacting carbon dioxide and methanol in the presence of a cerium/transition metal (CeM) catalyst prepared by calcining an organic framework (CeM-BTC). .
According to clause 12,
A method for producing dimethyl carbonate through direct conversion of carbon dioxide, characterized in that the amount of the catalyst used is 0.1 to 100 parts by weight based on 100 parts by weight of methanol.
According to clause 12,
A method for producing dimethyl carbonate through direct conversion of carbon dioxide, characterized in that catalytic reaction is carried out under conditions of a temperature range of 50 to 250 ° C. and a pressure range of 1 to 200 bar.