JP2002012578A - Method for producing dialkyl carbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently producing a dialkyl carbonate from CO, O2 and an alcohol. SOLUTION: This method for producing the dialkyl carbonate is characterized in that when producing the dialkyl carbonate by using the carbon monoxide, the oxygen and the alcohol as starting raw materials, a catalyst comprising (i) a copper compound free from a halogen atom and (ii) an alkoxy compound capable of forming a copper alkoxide by reacting with the copper compound is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a dialkyl carbonate. More specifically, the present invention relates to a method for efficiently producing a dialkyl carbonate from CO, O ₂ and an alcohol.

[0002]

BACKGROUND OF THE INVENTION In recent years, aromatic polycarbonates have been widely used in many fields as engineering plastics having excellent mechanical properties such as impact resistance and heat resistance and transparency. As a method for producing this aromatic polycarbonate, a so-called phosgene method in which an aromatic dihydroxy compound such as bisphenol is reacted with phosgene by an interfacial polycondensation method has been industrialized. However, the phosgene process that is currently practiced industrially requires the use of highly toxic phosgene, the problem of treating sodium chloride, which is a large amount of by-product, and the hygiene problem of methylene chloride, which is usually used as a reaction solvent. Many problems have been pointed out, such as air pollution and environmental problems.

As a method for producing an aromatic polycarbonate other than the phosgene method, there is known a method of performing a transesterification reaction between an aromatic dihydroxy compound and a carbonic acid diester using an alkali metal compound such as sodium hydroxide as a catalyst (melting method). ing. This method has an advantage that an aromatic polycarbonate can be produced at a low cost, and does not use toxic substances such as phosgene and methylene chloride.

In producing polycarbonate by such a melting method, diaryl carbonate such as diphenyl carbonate is used as diester carbonate. As described in JP-A-9-194430, this diaryl carbonate is produced by a transesterification reaction between a dialkyl carbonate and an aromatic hydrocarbon containing a hydroxyl group such as phenol, and is used as a raw material of the diaryl carbonate. Dialkyl is derived from carbon monoxide, oxygen and alcohol.
It is produced using a catalyst consisting of cuprous halide such as cuprous chloride.

For example, when methanol is used as an alcohol, dimethyl carbonate is produced by the following reaction: 2CH ₃ OH + CO + 1 / 2O ₂ → (CH ₃ O) ₂ CO + H ₂ O Cuprous chloride at this time is used as a catalyst, as a primary _{reaction, 2CuCl + 2CH 3 OH + 1} / 2O 2 → 2Cu (OCH 3) C
1 + H ₂ O forms methoxycupric chloride, and as a secondary reaction, 2Cu (OCH ₃ ) Cl + CO → (CH ₃ O) ₂ CO + 2Cu
It is estimated that it is regenerated by the reaction of Cl 2.

Incidentally, in order to improve the catalytic activity of cuprous halide used as such a catalyst, it has been disclosed that hydrohalic acid is added to the reaction system (Japanese Patent Laid-Open No. 5-194327). Reference). However, in the method using a cuprous halide as a catalyst as described above, the conversion of the cupric alkoxy chloride is low, so that the yield of dialkyl carbonate obtained is not always sufficient, and There is a problem that the reaction tank and the piping may be clogged by the catalyst, and the production efficiency is insufficient.

[0007] There is also a major problem that requires a countermeasure on equipment against corrosion of the apparatus by halogen. Under such circumstances, the present inventors have intensively studied a method for efficiently producing dialkyl carbonate, and as a catalyst, (i) a copper compound containing no halogen atom, and (ii)
By using a catalyst comprising an alkoxide compound capable of producing a copper alkoxide by reacting with the copper compound (i), the reaction proceeds while maintaining high catalytic activity, and the reaction proceeds by the catalyst, in a reaction tank or piping. The present inventors have found that diester carbonate can be obtained in high yield without clogging, etc., and furthermore, since it is non-halogen, there is no need to deal with equipment against corrosion by halogen, and the present invention has been completed.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above prior art, and has as its object to provide a method for efficiently producing a dialkyl carbonate from CO, O ₂ and alcohol.

[0009]

SUMMARY OF THE INVENTION The process for producing a dialkyl carbonate according to the present invention comprises the steps of: (i) producing a dialkyl carbonate starting from carbon monoxide, oxygen and an alcohol; A catalyst comprising an alkoxide compound capable of producing a copper alkoxide by reacting with the copper compound (i) is used.

The (i) copper compound containing no halogen atom includes cupric hydroxide (Cu (OH) ₂ ), cupric nitrate (Cu (N
O ₃ ) ₂ ), cupric acetate (Cu (OCOCH ₃ ) ₂ ), cupric sulfate (CuS
O ₄ ), basic copper carbonate (CuCO ₃ .Cu (OH) .H ₂ O), cupric sulfide
At least one compound selected from the group consisting of (CuS) is preferred. As the alkoxide compound (ii) capable of producing the copper alkoxide, an alkali metal alkoxide,
Alkaline earth metal alkoxide, represented by the following formula (1)
Preferred are at least one compound selected from the group consisting of quaternary ammonium alkoxides and quaternary phosphonium alkoxides represented by the following formula (2).

R ¹ R ² R ³ R ⁴ NOR ⁵ (1) R ¹ R ² R ³ R ⁴ POR ⁵ (2) (R ^{1 to} R ⁴ may be the same or different. Often represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and R ⁵ represents a hydrocarbon group having 1 to 20 carbon atoms.) An alkoxide compound capable of forming the copper alkoxide (ii)
Is, for a copper compound (i) containing no halogen atom,
It is preferably used in the range of 0.05 to 2.0 mol.

As the alcohol used in the method for producing a dialkyl carbonate according to the present invention, methanol is preferred.

[0013]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the method for producing a dialkyl carbonate according to the present invention will be specifically described. First, a starting material and a catalyst used in the method for producing a dialkyl carbonate according to the present invention will be described. [Starting Material and Catalyst] In the present invention, carbon monoxide (CO), oxygen (O ₂ ) and alcohol are used as starting materials.

The alcohol used as a starting material is not particularly restricted but includes, for example, methanol, ethanol, propanol, butanol, isopropanol, isobutanol, hexanol and the like. Of these, methanol is preferably used. In the present invention, (i) a copper compound containing no halogen atom and (ii) an alkoxide compound capable of reacting with the copper compound (i) to form a copper alkoxide are used as the catalyst.

The copper compound (i) containing no halogen atom includes cupric hydroxide (Cu (OH) ₂ ) and cupric nitrate (Cu (N
O ₃ ) ₂ ), cupric acetate (Cu (OCOCH ₃ ) ₂ ), cupric oxalate, cupric sulfide, cupric phosphate, cupric phthalate, cupric formate, cupric sulfate copper (CuSO _4), basic copper carbonate (CuCO ₃ · Cu (OH)
・ H ₂ O), cuprous hydroxide (CuOH), cuprous nitrate (CuNO ₃ ), cuprous acetate (CuOCOCH ₃ ), cuprous oxalate, cuprous sulfide, cuprous phosphate, Cuprous phthalate, cuprous formate, cuprous sulfate
An inorganic copper compound such as (Cu ₂ SO ₄ ) is used.

Of these, compounds containing divalent copper are preferred, and further, cupric hydroxide (Cu (OH) ₂ ), cupric nitrate
(Cu (NO ₃ ) ₂ ), cupric acetate (Cu (OCOCH ₃ ) ₂ ), cupric sulfate (Cu
SO ₄ ), at least one compound selected from the group consisting of basic copper carbonate (CuCO ₃ .Cu (OH) .H ₂ O) and cupric sulfide (CuS) is preferred. Two or more of these copper compounds containing no halogen atom may be used in combination.

(Ii) The alkoxide compound capable of forming a copper alkoxide by reacting with the copper compound (i) includes an alkali metal alkoxide, an alkaline earth metal alkoxide, and a quaternary compound represented by the following formula (1). At least one compound selected from the group consisting of ammonium alkoxides and quaternary phosphonium alkoxides represented by the following formula (2) is preferably used.

R ¹ R ² R ³ R ⁴ NOR ⁵ (1) R ¹ R ² R ³ R ⁴ POR ⁵ (2) (R ^{1 to} R ⁴ may be the same or different. Often, it represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and R ⁵ represents a hydrocarbon group having 1 to 20 carbon atoms.) As the alkali metal alkoxide, specifically, sodium methoxide, lithium methoxide , Potassium methoxide, rubidium methoxide, cesium methoxide, sodium ethoxide, lithium ethoxide, potassium ethoxide, rubidium ethoxide, cesium ethoxide,
Sodium propoxide, lithium propoxide, potassium propoxide, rubidium propoxide, cesium propoxide, sodium butoxide, lithium butoxide, potassium butoxide, rubidium butmethoxide,
Cesium butoxide, sodium pentoxide, lithium pentoxide, potassium pentoxide, rubidium pentoxide, cesium pentoxide, sodium hexoxide, lithium hexoxide, potassium hexoxide, rubidium hexoxide, cesium hexoxide,
Sodium heptoxide, lithium heptoxide, potassium heptoxide, rubidium heptoxide, cesium heptoxide, sodium octoxide, lithium octoxide, potassium octoxide, rubidium octoxide, cesium octoxide, sodium phenoxide, lithium phenoxide , Potassium phenoxide, rubidium phenoxide, cesium phenoxide and the like.

Specific examples of the alkaline earth metal alkoxide include mono- and di- such as beryllium, magnesium, calcium, strontium, barium methoxide, ethoxide, propoxide, butoxide, pentoxide, hexoxide, heptoxide, octoxide, phenoxide and the like. Alkoxide compounds are exemplified. As the quaternary ammonium alkoxide, specifically, tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium,
Tetrapentyl ammonium, tetraheptyl ammonium methoxide, tetraoctyl ammonium, methoxide of tetraphenyl ammonium, ethoxide, propoxide, butoxide, pentoxide, hexoxide,
Alkoxide compounds such as heptoxide, octoxide and phenoxide are exemplified.

Specific examples of the quaternary phosphonium alkoxide include methoxides of tetramethylphosphonium, tetraethylphosphonium, tetrapropylphosphonium, tetrabutylphosphonium, tetrapentylphosphonium, tetraheptylphosphonium methoxide, tetraoctylphosphonium, tetraphenylphosphonium,
Alkoxide compounds such as ethoxide, propoxide, butoxide, pentoxide, hexoxide, heptoxide, octoxide, phenoxide and the like can be mentioned.

Two or more of these alkoxide compounds may be used in combination. The (i) a copper compound containing no halogen atom, and (ii) an alkoxide compound capable of forming a copper alkoxide by reacting with the copper compound (i), reacting to form a copper alkoxide containing no halogen atom I do. As described above, when (i) a copper compound containing no halogen atom and (ii) an alkoxide compound capable of reacting with the copper compound to form a copper alkoxide are used in combination as a catalyst, carbon monoxide, oxygen, and an alcohol start. Since the catalyst has a high catalytic activity when producing dialkyl carbonate as a raw material and is stable during the reaction, the activity as a catalyst can be maintained for a long time.

[Production of dialkyl carbonate] In the present invention, the above-mentioned catalyst is used in producing dialkyl carbonate using carbon monoxide, oxygen and alcohol as starting materials. Specifically, first, a catalyst comprising (i) a copper compound containing no halogen atom and (ii) an alkoxide compound capable of producing a copper alkoxide by reacting with the copper compound (i), And reacting to prepare a starting alcohol containing a catalyst component.

It is desirable that (i) the copper compound containing no halogen atom is added in an amount of 0.001 to 1.0 mol, preferably 0.005 to 0.2 mol, per 1 mol of the alcohol. . (i) the copper compound and (ii) an alkoxide compound capable of producing a copper alkoxide by reacting with the copper compound, (i) a copper atom in the copper compound containing no halogen atom, (i)
i) moles of alkoxy groups in the alkoxide compound capable of producing a copper alkoxide by reacting with the copper compound (i),
It is preferable that (alkoxy group / Cu) is added in an amount in the range of 0.05 to 2.0 mol, preferably 0.1 to 1.2 mol.

Next, a gas of carbon monoxide and oxygen is introduced into the alcohol containing the catalyst component under pressure. In addition,
Carbon monoxide and oxygen may be individually supplied to the alcohol containing the catalyst component, or may be supplied after being mixed in advance. At this time, a gas that does not generate a reaction product in the reaction system, specifically, an inert gas such as hydrogen, nitrogen, carbon dioxide, methane, or argon may be present.

It is desirable that the amount of carbon monoxide introduced be greater than the stoichiometric number. Therefore, the molar ratio of carbon monoxide and oxygen introduced (carbon monoxide / oxygen) is 3/1 to 100/1, preferably 20/1 to 1
It is desirable to be in the range of 00/1. The reaction is usually
The reaction is carried out at a temperature of 50 to 200 ° C., preferably 100 to 150 ° C., under a pressure of atmospheric pressure to 150 atm, preferably 10 to 100 atm.

The above reaction produces dialkyl carbonate. According to the present invention, the yield of the obtained dialkyl carbonate can be improved. In addition,
The resulting dialkyl carbonate is separated by known separation methods such as distillation, filtration, decanting, centrifugation, demixing,
It is collected using osmosis membrane separation. These separation methods may be used in combination of two or more.

The catalyst, unreacted alcohol and the like contained in the reaction solution from which the produced dialkyl carbonate is recovered can be recovered and reused. Such a reaction can be performed using a batch-type reaction vessel or a continuous-type reaction vessel. It is desirable to use a pressure-resistant container such as an autoclave.

When a continuous reaction vessel is used, alcohol, carbon monoxide and oxygen can be mixed under the above-mentioned conditions by (i) a copper compound containing no halogen atom, and (ii) a copper compound (i). ) And an alcohol containing an alkoxide compound capable of producing a copper alkoxide by reacting with an alcohol. Then, the resulting dialkyl carbonate, water,
The reaction solution containing alcohol, unreacted carbon monoxide and water vapor are taken out, dialkyl carbonate and water are removed from the reaction solution, and other components are recycled to the reaction system.

The reaction solution to which the alcohol, carbon monoxide and oxygen are supplied may contain unrecovered dialkyl carbonate. The reaction solution to which alcohol, carbon monoxide and oxygen are supplied has an alcohol concentration of 30 to 80% by weight, preferably 35 to 80% by weight, and a water concentration of 1 to 1%.
It is desirably in the range of 0% by weight and 2 to 7% by weight. In the method for producing a dialkyl carbonate according to the present invention as described above, (i) a copper compound containing no halogen atom and (ii) an alkoxide compound capable of producing a copper alkoxide by reacting with the copper compound (i), Used as a catalyst. Therefore, in the present invention, dialkyl carbonate can be efficiently produced while maintaining high catalytic activity.

[0030]

According to the method for producing dialkyl carbonate according to the present invention, since a specific catalyst is used in combination, a high catalytic activity is maintained without clogging of a pipe or a reaction tank by the catalyst. In this state, dialkyl carbonate can be efficiently produced. Further, by performing polycondensation of a polycarbonate using a diaryl carbonate produced using the thus obtained dialkyl carbonate as a raw material, it is possible to obtain a polycarbonate having an improved hue. It is suitably used not only as a molding material, but also as a building material such as a sheet, a headlamp lens for an automobile, an optical lens such as eyeglasses, an optical recording material, etc., and is particularly suitable as a molding material for an optical disk.

[0031]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. The physical properties shown in the examples of the present invention are measured as follows.

[0032]

Example 1 In a Hastelloy autoclave having an internal volume of 300 ml, 47.4 g of methanol and 9.27 of cupric acetate were added.
g and 1.92 g of sodium methoxide (NaOCH ₃
/ Cu (OCOCH ₃ ) ₂ molar ratio = 0.7) and sealed. Then, the temperature of the autoclave was raised to 125 ° C., and the reaction gas (composition: O ₂ = 4.16%, N ₂ = 1.52%, CO 2
= 94.32%, CO ₂ = 0.00%) to 27.0 m
The mixture was supplied to the autoclave at a supply rate of 1 / min such that the total pressure was 2.5 to 2.6 MPa, and the reaction was carried out for 60 minutes.

After cooling the autoclave, the unreacted gas was slowly purged, the reaction solution was taken out, and the gas composition after the reaction and the reaction solution composition were quantitatively analyzed by gas chromatography. As a result, the conversion of methanol into dimethyl carbonate was 2.9 mol%, and the amount of dimethyl carbonate produced was 1.84 g.

Incidentally, methylal was confirmed as a by-product.

[0035]

Example 2 In a Hastelloy autoclave having an internal volume of 300 ml, 47.0 g of methanol and cupric hydroxide (Cu) were added.
(OH) ₂ ); 5.06 g, and 1.36 g of sodium methoxide (NaOCH ₃ / Cu (OH) ₂ molar ratio = 0.4
8) and sealed. Then, the autoclave was
The temperature was raised to 5 ° C. and the reaction gas (composition: O ₂ = 4.54%, N ₂
= 4.38%, CO = 91.08% , CO 2 = 0.00
%) At a feed rate of 17.5 ml / min and a total pressure of 2.5
To an autoclave to be ~ 2.6 MPa,
The reaction was performed for 60 minutes.

After cooling the autoclave, the unreacted gas was slowly purged, the reaction solution was taken out, and the gas composition after the reaction and the reaction solution composition were quantitatively analyzed by gas chromatography. As a result, the conversion of methanol into dimethyl carbonate was 3.4 mol%, and the amount of dimethyl carbonate produced was 2.16 g.

Incidentally, methylal was confirmed as a by-product.

[0038]

Example 3 In a Hastelloy autoclave having an inner volume of 300 ml, 48.7 g of methanol and cupric sulfide (Cu
S); 4.97 g, and sodium methoxide 2.0
7 g (NaOCH ₃ / CuS molar ratio = 0.74) was charged and sealed. Then, the temperature of the autoclave was raised to 125 ° C., and the reaction gas (composition: O ₂ = 5.08%, N ₂ = 2.53)
%, CO = 92.39%, CO ₂ = 0.00%)
At a feed rate of 7.5 ml / min, the total pressure is 2.5-2.6M
The mixture was supplied to an autoclave so that the pressure became Pa, and the mixture was reacted for 60 minutes.

After cooling the autoclave, the unreacted gas was slowly purged, the reaction solution was taken out, and the gas composition after the reaction and the reaction solution composition were quantitatively analyzed by gas chromatography. As a result, the conversion of methanol into dimethyl carbonate was 3.7 mol%, and the amount of dimethyl carbonate produced was 2.38 g.

Incidentally, methylal was confirmed as a by-product.

[0041]

Example 4 In a Hastelloy autoclave having an internal volume of 300 ml, 47.7 g of methanol and 9.20 of cupric acetate were added.
g and potassium methoxide 2.56 g (KOCH ₃ /
Cu (OCOCH ₃ ) ₂ molar ratio = 0.72) was charged and sealed. Then, the temperature of the autoclave was raised to 125 ° C., and the reaction gas (composition: O ₂ = 4.16%, N ₂ = 1.52%, C
O = 94.32%, CO ₂ = 0.00%)
The mixture was supplied to the autoclave at a supply rate of ml / min such that the total pressure became 2.5 to 2.6 MPa, and the reaction was carried out for 60 minutes.

After cooling the autoclave, unreacted gas was slowly purged, the reaction solution was taken out, and the gas composition after the reaction and the reaction solution composition were quantitatively analyzed by gas chromatography. As a result, the conversion of methanol into dimethyl carbonate was 2.5 mol%, and the amount of dimethyl carbonate produced was 1.61 g.

Incidentally, methylal was confirmed as a by-product.

[0044]

Comparative Example 1 In a Hastelloy autoclave having an internal volume of 300 ml, 47.2 g of methanol and cupric acetate Cu (OC) were added.
OCH ₃ ) ₂ : 9.23 g was charged and sealed. Next, the temperature of the autoclave was raised to 125 ° C., and the reaction gas (composition: O
₂ = 5.08%, N ₂ = 2.53%, CO = 92.39
%, CO ₂ = 0.00%) was supplied to the autoclave at a supply rate of 25.0 ml / min so that the total pressure became 2.5 to 2.6 MPa, and the reaction was carried out for 60 minutes.

After cooling the autoclave, unreacted gas was slowly purged, the reaction solution was taken out, and the gas composition after the reaction and the reaction solution composition were quantitatively analyzed by gas chromatography. As a result, the conversion of methanol into dimethyl carbonate was 0.7 mol%, and the amount of dimethyl carbonate produced was 0.47 g.

Incidentally, methylal was confirmed as a by-product.

[0047]

Comparative Example 2 In a Hastelloy autoclave having an internal volume of 300 ml, 47.2 g of methanol and cupric hydroxide Cu (O
H) ₂ ; 5.11 g was charged and sealed. Next, the temperature of the autoclave was raised to 125 ° C., and the reaction gas (composition: O ₂ =
5.08%, N ₂ = 8.44%, CO = 85.88%,
(CO ₂ = 0.00%) was supplied to the autoclave at a supply rate of 27.0 ml / min so that the total pressure became 2.5 to 2.6 MPa, and the reaction was carried out for 60 minutes.

After cooling the autoclave, the unreacted gas was slowly purged, the reaction solution was taken out, and the gas composition after the reaction and the composition of the reaction solution were quantitatively analyzed by gas chromatography. As a result, the conversion of methanol into dimethyl carbonate was 0.3 mol%, and the amount of dimethyl carbonate produced was 0.23 g.

Incidentally, methylal was confirmed as a by-product.

[0050]

Comparative Example 3 In a Hastelloy autoclave having an internal volume of 300 ml, 47.9 g of methanol and cupric sulfide: Cu were added.
S: 4.91 g was charged and sealed. Next, the temperature of the autoclave was raised to 125 ° C., and the reaction gas (composition: O ₂ = 5.
08%, N ₂ = 8.44%, CO = 85.88%, CO ₂
= 0.00%) was supplied to an autoclave at a supply rate of 21.5 ml / min such that the total pressure was 2.5 to 2.6 MPa, and the reaction was carried out for 60 minutes.

After cooling the autoclave, the unreacted gas was slowly purged, the reaction solution was taken out, and the gas composition after the reaction and the reaction solution composition were quantitatively analyzed by gas chromatography. As a result, the conversion of methanol into dimethyl carbonate was 0.2 mol%, and the amount of dimethyl carbonate produced was 0.11 g.

Incidentally, methylal was confirmed as a by-product.

[0053]

Comparative Example 4 In a Hastelloy autoclave having an internal volume of 300 ml, 46.7 g of methanol and Cu dimethoxide Cu were added.
(OCH ₃ ) ₂ : 6.20 g was charged and sealed. Next, the temperature of the autoclave was raised to 125 ° C., and the reaction gas (composition: O
₂ = 5.93%, N ₂ = 1.05%, CO = 93.02
%, CO ₂ = 0.00%), the total pressure being 2.5 to 2.6 M
The mixture was supplied to an autoclave so that the pressure became Pa, and the mixture was reacted for 30 minutes.

After cooling the autoclave, the unreacted gas was slowly purged, the reaction solution was taken out, and the gas composition after the reaction and the composition of the reaction solution were quantitatively analyzed by gas chromatography. As a result, the conversion of methanol into dimethyl carbonate was 0.8 mol%, and the amount of dimethyl carbonate produced was 0.53 g.

Incidentally, methylal was confirmed as a by-product.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tomoaki Shimoda 3 Chigusa Beach, Ichihara City, Chiba Prefecture Japan G-Plastics Co., Ltd. Chiba Works F-term (reference) 4H006 AA02 AC48 BA02 BA05 BA06 BA29 BA34 BA36 BE30 BE40 KA73 4H039 CA66 CF30

Claims (5)

[Claims] 1. A process for producing a dialkyl carbonate using carbon monoxide, oxygen and an alcohol as starting materials, wherein (i) a copper compound containing no halogen atom, and (ii) a copper compound obtained by reacting with the copper compound (i). A method for producing a dialkyl carbonate, comprising using a catalyst comprising an alkoxide compound capable of forming an alkoxide. 2. The method according to claim 1, wherein said (i) copper compound containing no halogen atom comprises cupric hydroxide (Cu (OH) ₂ ), cupric nitrate (Cu (NO ₃ ) ₂ ),
Group consisting of cupric acetate (Cu (OCOCH ₃ ) ₂ ), cupric sulfate (CuSO ₄ ), basic copper carbonate (CuCO ₃・ Cu (OH) ・ H ₂ O), cupric sulfide (CuS) The method for producing an alkyl carbonate according to claim 1, wherein the method is at least one copper compound selected from the group consisting of: 3. The alkoxide compound (ii) capable of forming a copper alkoxide is an alkali metal alkoxide, an alkaline earth metal alkoxide, a quaternary ammonium alkoxide represented by the following formula (1), and a compound represented by the following formula (2): The method for producing a dialkyl carbonate according to claim 1, wherein the compound is at least one compound selected from the group consisting of quaternary phosphonium alkoxides represented by the formula: R ¹ R ² R ³ R ⁴ NOR ⁵ . (1) R ¹ R ² R ³ R ⁴ POR ⁵ (2) (R ^{1 to} R ⁴ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. And R ⁵ represents a hydrocarbon group having 1 to 20 carbon atoms.) 4. The method according to claim 1, wherein the alkoxide compound (ii) capable of forming a copper alkoxide is a copper compound containing no halogen atom.
The method for producing a dialkyl carbonate according to any one of claims 1 to 3, wherein the compound is used in a range of 0.05 to 2.0 mol based on (i). 5. The method for producing a dialkyl carbonate according to claim 1, wherein the alcohol is methanol.