JPH09118652A - Production of chain carbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a chain carbonate useful as a synthetic raw material for electrolyte, etc., by transesterification without using a chemical substance poisonous to human bodies by using a specific catalyst. SOLUTION: Transesterification of a carbonate such as dimethyl carbonate with a monohydric alcohol such as ethyl alcohol is carried out in the presence of a catalyst comprising at least one kind of a metal oxide selected from III B group elements such as yttrium and samarium to provide the objective chain carbonate such as methylethyl carbonate or diethyl carbonate.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a chain carbonic acid ester. More specifically, the present invention relates to a method for producing a symmetrical and asymmetric chain ester carbonate in high yield by reacting a symmetrical ester carbonate with an alcohol using a specific catalyst. Chain carbonic acid ester is used for electrolyte, resin,
It is a compound useful as a solvent for paints, an alkylating agent, or a synthetic raw material for carbamates.

[0002]

2. Description of the Related Art Conventionally, carbonic acid esters have been produced by dehydrochlorination reaction of phosgene and alcohol, dehydrochlorination reaction of chloroformic acid ester and alcohol, or transesterification reaction of carbonic acid ester and alcohol. However, since phosgene is a toxic gas, a manufacturing process that avoids this use as much as possible is preferable. Further, since chloroformic acid ester is produced from phosgene as a raw material, the same thing as phosgene can be said.

On the other hand, in the production method by the transesterification reaction, the exchange reaction of the alcohol portion is carried out by the reaction between the alcohol and the carbonic acid ester in the presence of a homogeneous catalyst such as an alcohol solution of sodium methoxide or sodium hydroxide, and the carbonic acid ester and This is a preferred production process because it is produced by bringing alcohol into a thermal equilibrium composition and isolating the target carbonic acid ester by a separation means such as distillation.

[0004]

However, strong bases such as metal alkoxides used as catalysts for this transesterification reaction cause a great deal of damage to the human body when attached, and have a hygroscopic property and become contaminated with water. It has the drawback that it is difficult to handle and store due to deterioration. In addition, when such a homogeneous catalyst is used, it is necessary to add water to remove the catalyst after the reaction and to perform complicated steps such as an extraction treatment, especially when the purpose is to produce a carbonate ester containing no water. However, it takes a lot of work to remove the water added in the post-treatment. Further, since carbonate ester is a compound having a high hygroscopicity in itself, oil-water separation is often difficult in extraction treatment with water. A method of adding an extraction solvent may be considered in order to smoothly perform oil-water separation, but adding another solvent as an auxiliary material causes a problem that the manufacturing process is complicated. An object of the present invention is to provide a chain ester carbonate which is easy to produce and post-treat using a catalyst having excellent safety and stability and which can produce a target chain ester carbonate with high selectivity. It is to provide a manufacturing method of.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that the oxides of Group IIIB elements are found in many aspects as catalysts for transesterification of carbonic acid ester. They have found that they are excellent and have completed the present invention. That is, the present invention is characterized by using an oxide of at least one metal selected from Group IIIB elements as a catalyst when producing a chain carbonic acid ester by a transesterification reaction between a carbonic acid ester and a monohydric alcohol. Is a method for producing a chain carbonic acid ester. Hereinafter, the method of the present invention will be described in detail.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The transesterification reaction between a carbonic acid ester and a monohydric alcohol proceeds in the following two steps (formulaes (1) and (2)) to produce the desired chain carbonic acid ester and the corresponding alcohol. To do.

[0007]

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[0008]

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In the formulas (1) and (2), R ¹ represents an alkyl group, an aryl group or an alkoxyalkyl group, and R ² represents an alkyl group, an alkenyl group, an aromatic substituted alkyl group or an alkoxyalkyl group. A transesterification catalyst is required in order to rapidly and efficiently proceed the two-stage transesterification reaction represented by the above reaction formulas (1) and (2).

(Carbonate as a raw material) The carbonate used as a raw material in the present invention is a compound represented by the formula (I). The carbon number of the alkyl group R ¹ is not particularly limited, but is usually 1 to 12, preferably 1 to 6. The alkyl group may be linear, branched or cyclic. For example, the linear alkyl group may be a methyl group,
Examples thereof include ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group and dodecyl group. Examples of the branched alkyl group include isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, isoamyl group, tert-amyl group, neopentyl group, isohexyl group, sec-hexyl group, tert.
Examples thereof include -hexyl group and 2-ethylhexyl group. Further, examples of the cyclic alkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclododecyl group, and a norbornyl group.

Specific examples of the carbonic acid ester include dimethyl carbonate, diethyl carbonate, diisopropyl carbonate, dibutyl carbonate, diisobutyl carbonate, dicyclohexyl carbonate, diphenyl carbonate and di (2-methoxyethyl) carbonate. Of these, dimethyl carbonate or diethyl carbonate is easily available and advantageous.

(Raw material alcohol) The alcohol used as a raw material in the present invention is a monohydric alcohol represented by the formula (I '). The carbon number of the alkyl group R ² is not particularly limited, but is usually 1 to 12, and preferably 1 to 6. The alkyl group may be linear, branched or cyclic, for example, as the linear alkyl group, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, Examples thereof include an octyl group and a dodecyl group. Examples of the branched alkyl group include isopropyl group, isobutyl group, sec-butyl group, te
rt-butyl group, isoamyl group, tert-amyl group,
Examples include neopentyl group, isohexyl group, sec-hexyl group, and tert-hexyl group. Further, as the cyclic alkyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclododecyl group,
A norbornyl group can be mentioned.

Specific examples of the monohydric alcohol include methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol,
i-butyl alcohol, t-butyl alcohol, pentyl alcohol, hexyl alcohol, octyl alcohol, 2-ethylhexyl alcohol, decyl alcohol, dodecyl alcohol, tetradecyl alcohol, hexadecyl alcohol, octadecyl alcohol, cyclohexyl alcohol, allyl alcohol, benzyl alcohol, Examples thereof include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether and diethylene glycol monoethyl ether. Among them, aliphatic alcohols having 1 to 6 carbon atoms are preferable, and methanol and ethanol are particularly preferable from the viewpoint of reactivity.

(Catalyst) The catalyst used in the present invention contains an oxide of at least one metal selected from Group IIIB elements. If necessary, III B
You may contain the compound of the metal of the element other than a group element. II
Specific examples of the IB group element include La, Ce, Pr, Nd, Pm, Eu, Gd and T belonging to Sc, Y and lanthanides.
Examples thereof include b, Dy, Ho, Er, Tm, Yb and Lu, and Ac, Th, Pa and U belonging to actinides, and one or more of these can be used.
It is essential for the catalyst of the present invention to use these metal oxides of Group IIIB elements as catalysts. The Group IIIB element metal generally forms an oxide having an oxidation number of 3, but an oxide having an oxidation number of 4, a higher oxide, or a mixture thereof is not particularly limited. Absent.

Among these oxides, yttrium oxide and / or samarium oxide are preferable because they are industrially easily available. Here, the rare earth element is used to include Sc, Y, and lanthanide. To produce these oxides, for example, Group IIIB element metal oxalates, acetates,
A method of firing nitrates, hydroxides, carbonates, etc. in air is used. Also commonly sold III
Oxides of Group B element metals can also be used.

The oxide used as a catalyst is porous and has a specific ratio.
Larger ones are preferred because they provide higher catalytic activity
No. Specific surface area is usually 5-500m^Two/ G, more preferred
Is 10 to 300 m^Two/ G of oxide is used.
Specific surface area is 5m^Two/ G less than sufficient catalytic activity
It is not preferable because it does not occur. Also, the specific surface area is 500m ^Two
/ G, the strength of the catalyst is reduced, and there is a problem in durability.
It is not preferable because it causes a problem.

These oxides are used for the purpose of removing surface adsorbates such as carbon dioxide and water before they are used as catalysts.
It is preferable to activate by heat treatment in a stream of an inert gas such as nitrogen. The processing temperature at that time is 100.
℃ ~ 1000 ℃ range, more preferably 200 ℃ ~ 80
It is in the range of 0 ° C. If the treatment temperature is lower than 100 ° C., the desorption of the adsorbed substance becomes insufficient, which is not preferable. Further, if the treatment temperature exceeds 1000 ° C., the heat treatment is costly and the oxide partially melts to reduce the surface area, which is not preferable. The activation treatment time is not particularly limited because it depends on the amount of adsorbed substances on the surface and the treatment temperature, but it is usually in the range of 1 to 10 hours.

The shape of the catalyst is not particularly limited, but it is preferable that the catalyst is molded in order to facilitate liquid permeability during the reaction and separation of the catalyst after the reaction. The form may be a fine powder of about 100 μm or may be formed by a general method such as granulation or tableting. In preparing the catalyst, a suitable binder can be used. The binder is used for the purpose of binding the oxide solid of the catalyst to enhance the mechanical strength of the catalyst, and may be an inorganic substance or an organic substance as long as it does not inhibit the catalytic activity.
The binder is not particularly limited as long as it exhibits a certain degree of catalytic activity for the reaction. Specific examples of the binder, silica sol, alumina sol, zirconia sol,
Examples include organic polymers.

A suitable carrier may be used in preparing the catalyst. The carrier is used for the purpose of dispersing an oxide of a Group IIIB element metal on the surface thereof to form a catalyst having a high surface area or increasing the mechanical strength of the catalyst. The carrier is not particularly limited as long as it does not inhibit the reaction or the catalytic activity, and may have some catalytic activity for the reaction. Specific examples of the carrier, silica, alumina, zirconia, titania, silica-alumina, zirconia-titania, silica-zirconia, alumina-titania, silica-titania, inorganic carriers such as alumina-zirconia, kaolinite kaolinite,
Dickite, halloysite, chrysotile, lizardite, amethite, etc. and smectite montmorillonite, beidellite, saponite, hectorite, sauconite, mica muscovite, paragonite, phlogopite, biotite, levidrite, hydrotalcite, etc.
Examples thereof include clay compounds such as talc.

(Solvent) The transesterification reaction proceeds in the liquid phase. At this time, since the carbonic acid ester of the raw material and the alcohol itself play a role of a solvent, it is not necessary to use another solvent, and it is preferable not to use it from the viewpoint of easiness of post-treatment, but in a solvent that does not react with the raw material and the product. You can use it if you like. Examples of such a solvent include aromatic hydrocarbon solvents, saturated hydrocarbon solvents, unsaturated hydrocarbon solvents, ether solvents, amide solvents, and the like, and these can be used alone or in combination.

(Reaction Method) Next, the reaction method for transesterification according to the present invention will be described. The composition ratio of the chain carbonic acid ester which is the product changes depending on the charged molar ratio of the carbonic acid ester as a raw material and the alcohol. Therefore, by appropriately selecting the charged molar ratio of the raw materials,
The composition ratio of the desired chain ester carbonate (II) or (III) can be increased. There is no particular limitation on the molar ratio of the carbonic acid ester as the raw material and the alcohol, but if the molar ratio of the alcohol to the carbonic acid ester is too large, the amount of the recovered alcohol becomes excessive, while if it is too small, the conversion rate of the raw carbonic acid ester becomes low. Therefore, the molar ratio of the alcohol to the raw material carbonic acid ester is usually 0.1 to 50, preferably 0.5 to 5.

The method of transesterifying the monohydric alcohol and the carbonic acid ester may be a batch reaction or a flow reaction, and is not particularly limited. The amount of the catalyst used in the batch reaction is 0.1 to 3 with respect to the raw materials.
It is in the range of 0% by weight, more preferably 1 to 15% by weight. A batch type reactor is filled with a predetermined amount of catalyst and raw material,
By carrying out the transesterification reaction with stirring at a predetermined temperature, a reaction liquid mixture containing the target chain carbonate can be obtained. At that time, the reaction time varies depending on the reaction temperature and the amount of the catalyst used, but is generally 0.1 to 100 hours, and more preferably 1 to 40 hours. When carrying out a flow-through reaction, any of a fixed bed system, a fluidized bed system, and a stirring tank system can be used. The liquid passing conditions at this time are, when expressed as a liquid hourly space velocity (LHSV) with respect to the catalyst, 0.05 to 50 / hour, more preferably 0.1 to 10.
A range of / hour can be used.

The reaction temperature is not particularly limited, but the reaction is usually carried out in the range of 0 to 300 ° C. in an atmosphere of an inert gas such as nitrogen. 50 to 200 ° C from the viewpoint of ease of manufacturing process
Is preferable. The reaction pressure is not particularly limited,
The reaction can be carried out under reduced pressure to 200 kg / cm ² -G, but usually in the range of 0 to 60 kg / cm ² -G, preferably 0 to 30 kg / cm ² -G.

After the reaction, the reaction mixture can be filtered to remove the finely divided catalyst. However, a trace amount of catalyst components may be dissolved in the reaction solution depending on the combination of the catalyst and alcohol used.In that case, the reaction mixture contains solid acid substances such as activated clay, silica gel, and ion exchange resins. The catalyst can be removed by adding or by passing the reaction mixture through a packed column. As described above, according to the present invention, the catalyst can be removed without using water, so that it is not necessary to perform time-consuming and time-consuming water removal as oil-water separation or post-treatment.

The reaction mixture after removal of the catalyst can be separated into the carbonic acid ester as a raw material, the carbonic acid ester as a reaction product and the alcohols by a known means such as atmospheric distillation, reduced pressure distillation and pressure distillation. In the method for producing a carbonic acid ester of the present invention, since the carbonic acid ester as a raw material, the carbonic acid ester as a product, and other products of alcohol are not present, the desired product can be obtained with high selectivity, and further, after separation. The raw material can be recovered and reused.

[0026]

EXAMPLES The method of the present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Catalyst Production Example 1 400.0 g (0.9 mol) of samarium nitrate hexahydrate was dissolved in 1000 g of water to obtain a samarium nitrate aqueous solution.
While stirring, 3500 g of a 12% ammonium bicarbonate aqueous solution was added to the samarium nitrate aqueous solution to obtain a samarium hydroxide slurry. This slurry was separated by filtration and washed sufficiently with pure water until the pH became neutral to obtain a samarium hydroxide hydrate. The samarium hydroxide thus obtained is used in air 12
It was dried at 0 ° C. for 12 hours and further calcined at 600 ° C. for 3 hours to obtain samarium oxide, which was used as a catalyst (1).

Catalyst Production Example 2 Yttrium nitrate hexahydrate 344.7 g (0.9 mol)
In the same manner as in Example 1 except that samarium nitrate was used instead, yttrium oxide was obtained, and the catalyst (2) was obtained.
And

Catalyst Production Example 3 Example except that 172.3 g (0.45 mol) of yttrium nitrate hexahydrate and 131.1 g (0.45 mol) of cobalt nitrate hexahydrate were used in place of samarium nitrate. The same operation as in 1 was performed to obtain a yttrium / cobalt composite oxide. The resulting catalyst had a metal atomic ratio of yttrium to cobalt of 1: 1. This catalyst is a catalyst (3)
And

Example 1 To a mixed solution of 461 g (10 mol) of ethyl alcohol and 901 g (10 mol) of dimethyl carbonate (molar ratio = 1: 1) was added 36.0 g (0.1 mol) of the catalyst (1), and 100 It was immersed in an oil bath at ℃ and heated for 30 hours. After the reaction, the reaction mixture was analyzed by gas chromatography.
As a result, the composition of the reaction mixture was 18
6 g (5.8 mol), 194 g of ethyl alcohol (4.
2 mol), 441 g (4.9 mol) of dimethyl carbonate, 458 g (4.4 mol) of ethyl methyl carbonate and 83 g (0.7 mol) of diethyl carbonate, no other products were observed.

Further, after cooling the reaction mixture to room temperature,
The catalyst was filtered off, and the filtrate was distilled at atmospheric pressure using a distillation column with 20 theoretical plates without any treatment to obtain 391 g of methyl ethyl carbonate and 36 g of diethyl carbonate. The yields of methyl ethyl carbonate and diethyl carbonate based on the charged dimethyl carbonate were 37.6% and 3.0%, respectively.

Example 2 In the method of Example 1, the molar ratio of the starting material ethyl alcohol and dimethyl carbonate was changed, the rest of the reaction was carried out in the same manner as described above, and the composition of the reaction mixture was analyzed by gas chromatography. The measured values obtained are shown in Table 1 in terms of molar ratio.

[0033]

[Table 1] * 1: Ethyl alcohol * 2: Dimethyl carbonate * 3: Ethyl methyl carbonate * 4: Diethyl carbonate

Example 3 345.8 g (7.5 mol) of ethyl alcohol and 225.3 g (2.5 mol; molar ratio = 3: 1) of dimethyl carbonate were mixed in a stainless steel autoclave equipped with a stirrer having a capacity of 1000 ml. Solution and catalyst (1) 9.0
g (0.025 mol) was charged. Then, the inside of the reactor was replaced with nitrogen to a nitrogen pressure of 2 kg / cm ² -G, and then 14
The reaction was carried out at 0 ° C for 4 hours. The reaction pressure gradually increases as the reaction progresses, and at 140 ° C., 6.7 at the start of the reaction.
kg / cm ² -G, 7.2 kg / cm ² at the end of the reaction
-G.

After completion of the reaction, the reaction solution was analyzed and the composition of the obtained reaction mixture was 87 g of methyl alcohol.
(2.7 mol), ethyl alcohol 222 g (4.8 mol), dimethyl carbonate 45 g (0.5 mol), ethyl methyl carbonate 136 g (1.3 mol), diethyl carbonate 81 g (0.7 mol) No product was found.

Further, after cooling the reaction mixture to room temperature,
The catalyst was filtered off, and the filtrate was distilled at atmospheric pressure using 20 theoretical plates and the like without any treatment to obtain 87 g of methyl ethyl carbonate and 32 g of diethyl carbonate. The yields of methyl ethyl carbonate and diethyl carbonate based on the charged dimethyl carbonate were 33.4% and 10.8%, respectively.

Example 4 In the method of Example 3, the same operation was carried out using 7.4 g (0.033 mol) of the catalyst (2) instead of the catalyst (1) as the catalyst. The composition of the resulting reaction mixture is
Methyl alcohol 93 g (2.9 mol), ethyl alcohol 212 g (4.6 mol), dimethyl carbonate 4
0.5 g (0.45 mol), ethyl methyl carbonate 125 g (1.2 mol), diethyl carbonate 99 g
No other product was observed (0.85 mol).

Example 5 In the method of Example 3, the same operation was carried out using 5.0 g (0.033 mol) of the catalyst (3) instead of the catalyst (1) as the catalyst. The composition of the resulting reaction mixture is
Methyl alcohol 90 g (2.8 mol), ethyl alcohol 216 g (4.7 mol), dimethyl carbonate 4
5 g (0.5 mol), ethyl methyl carbonate 130
g (1.25 mol), 89 g of diethyl carbonate
No other product was observed at (0.75 mol).

Comparative Catalyst Production Example 1 The procedure of Example 1 was repeated except that 261.9 g (0.9 mol) of cobalt nitrate hexahydrate was used in place of samarium nitrate to obtain cobalt oxide, and the catalyst ( 4).

Comparative Example 1 2.5 g of the catalyst (4) was used instead of the catalyst (1) as the catalyst.
The same operation as in Example 6 was performed except that (0.033 mol) was used. The composition of the resulting reaction mixture was as follows: methyl alcohol 10 g (0.3 mol), ethyl alcohol 332 g (7.2 mol), dimethyl carbonate 19
8 g (2.2 mol), ethyl methyl carbonate 31 g
(0.3 mol), 1.2 g of diethyl carbonate (0.
No other product was observed at (01 mol).

[0041]

According to the method of the present invention, by using a solid and highly active metal oxide of a Group IIIB element as a catalyst for a transesterification reaction of carbonic acid ester, the catalyst itself does not deteriorate due to moisture absorption and is stored and handled. The production process of the carbonate ester can be facilitated and simplified without using a dangerous substance as a raw material. Further, according to the carbonic acid ester production process of the present invention, the post-reaction catalyst and the reaction product can be easily separated, and it is not necessary to use water in the catalyst removal process, so that the post-reaction treatment can be simplified. Furthermore, according to the present invention, by using such a catalyst, it is possible to carry out a reaction with high selectivity and without reaction by-products.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Ogaki 8-3-1 Chuo, Ami-cho, Inashiki-gun, Ibaraki Mitsubishi Chemical Corporation Tsukuba Research Center

Claims (3)

[Claims] 1. A method for producing a chain carbonic acid ester by transesterification of a carbonic acid ester and a monohydric alcohol, wherein at least one metal oxide selected from Group IIIB elements is used as a catalyst. A method for producing a chain carbonic acid ester. 2. The method for producing a chain carbonate ester according to claim 1, wherein the catalyst is an oxide of yttrium and / or samarium. 3. The method for producing a chain carbonic ester according to claim 1, wherein the carbonic acid ester to be subjected to the transesterification reaction is dimethyl carbonate, and the monohydric alcohol is ethyl alcohol.