JP2021069968A - Catalyst for production of organic carbonate and method for producing organic carbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method capable of obtaining an organic carbonate in a high yield by a method using no phosgene, and a catalyst for producing an organic carbonate used in the production method. SOLUTION: It contains cerium oxide (a) and a silicate (b) composed of silica (SiO2) and / or an aluminosilicate (c) composed of silica (SiO2) and alumina (Al2O3). A catalyst for producing organic carbonate and a method for producing organic carbonate. [Selection diagram] None

Description

The present invention relates to a catalyst for producing an organic carbonate and a method for producing an organic carbonate.

Organic carbonate is an organic chemical product that is expected to be industrially useful as a raw material for polymer materials, an octane number improver for gasoline, a methylating agent in organic synthesis, a carbonylating agent, and the like.

Conventionally, organic carbonates have been synthesized using phosgene and alcohol, but in recent years, it has been studied to use inexpensive and abundant carbon dioxide as a carbonyl source. If carbon dioxide can be used as a carbonyl source, it will be possible to synthesize organic carbonates with a low environmental load. However, the direct synthesis of organic carbonates from carbon dioxide and alcohols is less reactive. For example, in Non-Patent Document 1, dimethyl carbonate (DMC) is synthesized from carbon dioxide and methanol, but the yield is as low as 7.3%.

G. Fan, et al. , J. Mol Catal. A, 404, 92 (2015)

Based on such a problem, an object of the present invention is to provide a production method capable of obtaining an organic carbonate in a high yield by a method that does not use phosgene, and a catalyst for producing an organic carbonate used in the production method. And.

The present inventor has an aluminosilicate composed of cerium oxide (a) and silica (SiO ₂ ) and / or silica (SiO ₂ ) and alumina (Al ₂ O _3). It has been found that the catalyst containing (c) becomes a catalyst having a high organic carbonate yield. Furthermore, when the above-mentioned organic carbonate catalyst is used, the organic carbonate can be obtained in a high yield in the presence of alcohol and carbon dioxide having 1 or more and 20 or less carbon atoms, and the amount of by-products produced can be reduced. I found out what I could do. Further, they have found that the pressure of carbon dioxide used for the reaction can be lowered by using the above-mentioned organic carbonate catalyst and can be easily produced, and the present invention has been completed.

That is, in the present invention, the silicate (b) composed of _{cerium oxide (a) and silica (SiO 2} ) and / or the aluminosilicate composed of _{silica (SiO 2} ) and alumina (Al ₂ O ₃₎ A catalyst for producing an organic carbonate, which comprises a salt (c), and a method for producing an organic carbonate.

According to the present invention, it is possible to provide a method for producing an organic carbonate capable of obtaining an organic carbonate in a high yield without using phosgene, and a catalyst for producing an organic carbonate used in the method for producing the organic carbonate.

Hereinafter, the present invention will be described in more detail.
The catalyst for producing organic carbonate of the present invention is _{composed of cerium oxide (a), silicate (b) composed of silica (SiO 2} ) and / or silica (SiO ₂ ) and alumina (Al ₂ O ₃ ). It contains the aluminosilicate (c) to be produced.

Examples of the cerium (a) contained in the catalyst for producing an organic carbonate of the present invention include cerium (III) oxide (Ce ₂ O ₃ ) and cerium (IV) ( _{Ce O 2} ). At normal temperature and pressure, cerium (III) oxide (Ce ₂ O ₃ ) and cerium (IV) oxide _{(Ce O 2} ) are stably present. Either cerium (III) oxide (Ce ₂ O ₃ ) or cerium (IV) oxide (CeO ₂ ) may be used, but in general, it is preferable to use cerium (IV) oxide, which is more easily available.

Examples of the silicate (b) composed of _{silica (SiO 2} ) contained in the catalyst for producing organic carbonate of the present invention include silica gel and the like. Silica gel is not particularly limited. Silica gel refers to a porous gel in which colloidal particles of silicon dioxide are aggregated.

Examples of the aluminosilicate (c) composed of _{silica (SiO 2} ) and alumina (Al ₂ O ₃ ) contained in the catalyst for producing organic carbonate of the present invention include zeolite and the like. Zeolite means crystalline aluminosilicate. Crystalline aluminosilicate is a porous body having a skeleton structure of a network formed by silicon (Si) and aluminum (Al) via oxygen (O).

The molar ratio of silica to alumina of zeolite (hereinafter referred to as “SiO ₂ / Al ₂ O ₃ ratio”) is not particularly limited. As a preferable SiO ₂ / Al ₂ O ratio, 2 or more and 3000 or less can be exemplified.

The zeolite structure of the aluminosilicate (c) is not particularly limited. Zeolite structure refers to the skeletal structure of the structural code defined by the International Zeolite Society. Preferably, an aluminosilicate belonging to any of the skeletal type codes of FAU, LTL, MOR, FER, MFI, BEA, LTA, CHA and ERI can be exemplified.

Regarding the silicate and aluminosilicate used in the present invention, one type may be used alone or two or more types may be used in combination. It may be a commercially available product or a product synthesized by a known method. Further, the silicate and the aluminosilicate may be used as they are or after appropriate pretreatment, or may be separately prepared and used. The conditions for pretreatment are not particularly limited.

The catalyst for producing an organic carbonate of the present invention preferably contains acetal (d) in order to produce the organic carbonate more efficiently. Examples of the acetal (d) include acetals having the structure shown in the formula (1), and R ¹ shown in the formula (1) has the same structure as ^{R 2} shown in the formula (2). Acetals are preferred. Specific examples of the acetal include 2-diethoxypropane (DEP) and 2-dimethoxypropane (DMP).

（式（１）において、Ｒ^１は炭化水素基、又は炭化水素基の水素原子を置換基で置換した基を表す。）

(In the formula (1), R ¹ represents a hydrocarbon group or a group in which a hydrogen atom of a hydrocarbon group is substituted with a substituent.)

The catalyst for producing an organic carbonate of the present invention is usually preferably used as a catalyst solution in which cerium oxide, silicate and / or aluminosilicate are dispersed in a solvent, although it depends on the size of the reactor. Cerium oxide, silicate, and aluminosilicate may be used alone or as a mixture of two or more kinds.

Examples of the solvent for dispersing cerium oxide and the like include alcohol, tetrahydrofuran (THF) and the like, and alcohol having 1 or more and 20 or less carbon atoms is preferable, and alcohol having 1 or more and 6 or less carbon atoms is more preferable. Examples of the alcohol include ethanol, methanol and the like. When alcohol is used as a solvent for dispersing cerium oxide or the like, carbon dioxide can be obtained by putting carbon dioxide in the solvent in which cerium oxide or the like is dispersed in the production stage of the organic carbonate.

Hereinafter, a method for producing an organic carbonate using the catalyst for producing an organic carbonate of the present invention will be described in detail.
Examples of the organic carbonate obtained by the method for producing an organic carbonate of the present invention include diethyl carbonate (DEC) and dimethyl carbonate (DMC), but diethyl carbonate (DEC) is preferable.

The catalyst for producing organic carbonate of the present invention can be used as a catalyst for producing organic carbonate by using this, alcohol and carbon dioxide (or carbon dioxide). The number of carbon atoms of the alcohol is not particularly limited, but in order to maintain high reactivity and reduce the load of distillation removal after the reaction, the number of carbon atoms is preferably 1 or more and 20 or less, and the number of carbon atoms is 1 or more and 6 or less. It is more preferable if there is. Examples of the alcohol include ethanol, methanol and the like, but ethanol is preferable.

（式（２）において、Ｒ^２は、それぞれ、炭化水素基、又は炭化水素基の水素原子を置換基で置換した基を表す。） The reaction formula for synthesizing an organic carbonate from alcohol and carbon dioxide is, for example, represented by the following formula (2).

(In the formula (2), R ² represents a hydrocarbon group or a group in which a hydrogen atom of a hydrocarbon group is substituted with a substituent, respectively.)

The type of organic carbonate obtained by the synthetic reaction of the above formula (2) depends on the carbon number of the alcohol as a raw material. As an example, when ethanol is used as the raw material, diethyl carbonate (DEC) is obtained.

（式（３）において、Ｒ^１は、それぞれ、炭化水素基、又は炭化水素基の水素原子を置換基で置換した基を表す。） When the catalyst for producing an organic carbonate contains acetal represented by the above formula (1), it is by-produced with acetal according to the formula (2) as shown by the reaction formula of the following formula (3). Reacts with water to produce acetone and alcohol.

(In the formula (3), R ¹ represents a hydrocarbon group or a group in which a hydrogen atom of a hydrocarbon group is substituted with a substituent, respectively.)

The type of alcohol obtained by the synthetic reaction of formula (3) depends on the number of carbon atoms of the acetal used. As an example, when DEP is used as the acetal, the product is ethanol. When ethanol is used as a raw material in the synthetic reaction of the formula (2), by using DEP as an acetal, ethanol necessary for the production of diethyl carbonate (DEC) can be supplied from the by-produced water.

As described above, in the method for producing an organic carbonate, from silicate (b) composed of _{cerium oxide (a) and silica (SiO 2 ) and / or silica (SiO 2} ) and alumina (Al ₂ O ₃ ). As shown in the formula (2), organic carbonate and water are produced from the reaction between alcohol and carbon dioxide by the constituent aluminosilicate (c) and the acetal (d) -containing catalyst for producing organic carbonate. Then, as shown in the formula (3), the by-produced water reacts with the acetal to produce alcohol.

In the method for producing an organic carbonate of the present invention, for example, the catalyst for producing an organic carbonate of the present invention is placed in a reactor, alcohol and carbon dioxide are supplied thereto, and the catalyst is heated with stirring for reaction.

Further, in the method for producing organic carbonate of the present invention, for example, when the catalyst for producing organic carbonate of the present invention is dispersed in alcohol, the catalyst for producing organic carbonate of the present invention is placed in a reaction apparatus to form carbon dioxide. Carbon (or alcohol and carbon dioxide) is supplied and heated with stirring to react.

The apparatus and reaction mode used for producing the organic carbonate are not particularly limited. Either a batch device or a continuous device may be used. The stirring mode is not particularly limited, and for example, a stirrer or a stirring blade is used depending on the size of the reactor. Carbon dioxide is supplied from the source to the reactor, and the carbon dioxide pressure in the reactor is adjusted to be within a predetermined range.

The amount of the catalyst for producing an organic carbonate is not limited, and is preferably in the range of 0.5% by mass to 50% by mass with respect to the amount of cerium oxide added. There are no restrictions on the shape of cerium oxide, silicate, and aluminosilicate, and they are usually used as powder, granules, or molded products. There is no limitation on the order in which the raw materials and the catalyst for producing organic carbonate are mixed.

The reaction temperature is preferably, for example, in the range of 350K or more and 460K or less, and more preferably in the range of 370K or more and 440K or less. This is because the reaction can be performed well within this range. The pressure (absolute pressure) of carbon dioxide is preferably in the range of 1 MPa or more and 10 MPa or less, and more preferably in the range of 3 MPa or more and 8 MPa or less. This is because the reaction can be performed well within this range. The reaction time is, for example, about 1 hour or more and 24 hours or less.

The present invention will be specifically described with reference to the following examples, but the present invention is not limited to the examples.

Example 1
Prepare a 190 mL autoclave as a reaction device, put 140 mmol of ethanol, 21 mmol of DEP, 0.5 g of cerium oxide, and 0.1 g of silica gel (CARIACT G-6, manufactured by Fuji Sicilian) in it, and stir at room temperature to produce an organic carbonate. A solution of the production catalyst was prepared.
Carbon dioxide was added to the prepared solution of the catalyst for producing organic carbonate, and the autoclave was heated. The pressure of carbon dioxide was 5 MPa. The reaction was carried out at a reaction temperature of 393 K for 4 hours to obtain diethyl carbonate (DEC). The conversion rate, yield, and production amount are shown in Table 1. The conversion rate and the yield are values calculated on a DEP basis (the same applies hereinafter).

Example 2
The same operation as in Example 1 was carried out except that an LTA-type zeolite (4 Å, manufactured by Sigma-Aldrich) was used instead of silica gel to obtain diethyl carbonate (DEC). The conversion rate, yield, and production amount are shown in Table 1.

Example 3
The same operation as in Example 1 was carried out except that BEA type zeolite (HSZ (registered trademark) -930HOA, manufactured by Tosoh) was used instead of silica gel to obtain diethyl carbonate (DEC). The conversion rate, yield, and production amount are shown in Table 1.

Example 4
The same operation as in Example 1 was carried out except that FAU-type zeolite (CBV740, manufactured by Zeolist) was used instead of silica gel to obtain diethyl carbonate (DEC). The conversion rate, yield, and production amount are shown in Table 1.

Example 5
The same operation as in Example 1 was carried out except that LTL-type zeolite (HSZ (registered trademark) -500KOA, manufactured by Tosoh) was used instead of silica gel to obtain diethyl carbonate (DEC). The conversion rate, yield, and production amount are shown in Table 1.

Example 6
The same operation as in Example 1 was carried out except that MOR-type zeolite (manufactured by Tosoh) was used instead of silica gel to obtain diethyl carbonate (DEC). The conversion rate, yield, and production amount are shown in Table 1.

Example 7
The same operation as in Example 1 was carried out except that FER-type zeolite (HSZ (registered trademark) -720KOA, manufactured by Tosoh) was used instead of silica gel to obtain diethyl carbonate (DEC). The conversion rate, yield, and production amount are shown in Table 1.

Example 8
The same operation as in Example 1 was carried out except that MFI-type zeolite (HSZ (registered trademark) -840NHA, manufactured by Tosoh) was used instead of silica gel to obtain diethyl carbonate (DEC). The conversion rate, yield, and production amount are shown in Table 1.

Example 9
Diethyl carbonate (DEC) was obtained in the same manner as in Example 1 except that 80 mmol of ethanol and 5 MPa of carbon dioxide were added to the prepared solution of the catalyst for producing organic carbonate (140 mmol of ethanol was changed to 60 mmol). The conversion rate, yield, and production amount are shown in Table 1.

Example 10
Diethyl carbonate (DEC) was obtained in the same manner as in Example 9 except that 35 mmol of tetrahydrofuran (THF) was used instead of 60 mmol of ethanol in the preparation of the solution of the catalyst for producing organic carbonate. The conversion rate, yield, and production amount are shown in Table 1.

Comparative Example 1
The same operation as in Example 1 was carried out except that silica gel was not used to obtain diethyl carbonate (DEC). The conversion rate, yield, and production amount are shown in Table 1.
According to Table 1, all the examples were able to obtain higher conversion rates and yields than the comparative examples.

Claims (8)

Contains cerium oxide (a) and silicate (b) composed of _{silica (SiO 2} ) and / or aluminosilicate (c) composed of _{silica (SiO 2} ) and alumina (Al ₂ O ₃₎ A catalyst for the production of organic carbonate. The catalyst for producing an organic carbonate according to claim 1, wherein the silicate (b) composed of silica (SiO _{2) is silica gel.} The catalyst for producing an organic carbonate according to claim 1, wherein the aluminosilicate (c) composed of silica (SiO ₂ ) and alumina (Al ₂ O _{3) is a zeolite.} The organic carbonate production according to claim 3, wherein the zeolite is a zeolite selected from the group of any skeletal type code of FAU, LTL, MOR, FER, MFI, BEA, LTA, CHA, and ERI. For catalyst. A catalyst for producing an organic carbonate according to any one of claims 1 to 4, wherein the catalyst for producing an organic carbonate further contains acetal (d). A method for producing organic carbonate, which comprises supplying carbon dioxide by using the catalyst for producing organic carbonate according to any one of claims 1 to 5. A method for producing an organic carbonate, which comprises reacting an alcohol with carbon dioxide in the presence of the catalyst for producing an organic carbonate according to any one of claims 1 to 5. The method for producing an organic carbonate according to claim 7, wherein the alcohol is an alcohol having 1 or more and 20 or less carbon atoms.