JPH10237026A - Production of asymmetric chain carbonate compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the subject compound in a highly selective and simple process by subjecting two kinds of symmetric chain carbonate to a disproportionation reaction by using a stable and highly active heterogeneous catalyst containing a titanium oxide and not dissolving in resultant reaction- produced solution. SOLUTION: This asymmetric chain carbonate compound (e.g. ethyl methyl carbonate) is obtained by subjecting two kinds of symmetric chain carbonate (e.g. dimethyl carbonate and diethyl carbonate) to a disproportionation reaction in an inert gas atmosphere usually at 0-300 deg.C under 0-50kg/cm<2> G, preferably at 50-200 deg.C under 0-10kg/cm<2> G by using a catalyst containing an oxalate, an acetate, a hydroxide, a carbonate, etc., of titanium baked in air, or a market- sold porous titanium oxide having usually 5-500m<2> /g specific surface area as a catalyst activating component and preferably using the catalyst activated by heat-treating at 100-1,000 deg.C for usually 1-10hrs in a stream of an inert gas such as a nitrogen gas before using.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an asymmetric chain carbonate. Specifically, the present invention relates to a method for producing an asymmetric carbonate by subjecting two kinds of target chain carbonates to a disproportionation reaction using a specific catalyst.
The asymmetric carbonate is useful as a solvent or various organic synthesis reagents, and is particularly effective as a solvent for an electrolyte for a lithium ion secondary battery.

[0002]

2. Description of the Related Art Carbonic acid is a weak dibasic acid, and its esters include monoesters and diesters. Diesters contain a symmetric chain carbonic acid ester containing the same kind of alkyl group and two kinds of alkyl groups. And asymmetric chain carbonates. Hitherto, as a method of industrially obtaining a chain carbonate, a method of reacting phosgene with an alcohol, a method of reacting an alcohol with carbon monoxide and oxygen in the presence of a catalyst, and the like have been proposed.

[0003] However, since phosgene is a toxic gas, a production process which avoids its use as much as possible is preferred. On the other hand, the method of reacting an alcohol with carbon monoxide and oxygen in the presence of a catalyst is intended to produce a symmetric chain carbonate, and the present invention is intended to produce an asymmetric chain carbonate. Not very suitable.

Therefore, conventionally, in producing an asymmetric chain carbonate, (i) transesterification of a symmetric chain carbonate with an alcohol having another alkyl group, or (ii) two kinds of symmetric chain carbonates are carried out. A method has been adopted in which the ester is subjected to a disproportionation reaction to obtain the desired asymmetric chain carbonate from the equilibrium mixture.

As an example of the method (i), Japanese Unexamined Patent Publication No.
No. 6660 discloses a method for producing an asymmetric carbonate by subjecting a monohydric alcohol and a symmetric chain carbonate to interesterification with an alkali metal carbonate as a catalyst. However, the alkali metal carbonate used as a catalyst for the transesterification reaction has low solubility in alcohol, but is not completely insoluble. Therefore, a carbonate removal step is required to prevent a slight amount of carbonate present in the reaction solution from causing a reverse reaction in the subsequent separation step, and there is a drawback that it takes a little time and effort. In addition, alkali metal carbonates are generally easily soluble in water, and there is a potential problem that the reaction process will be seriously hindered if the catalyst comes into contact with water due to some erroneous operation.

As an example of (ii), JP-A-7-10
No. 811, which includes an asymmetric chain carbonate produced using a basic catalyst such as an alkali metal alcoholate.
A process is disclosed for obtaining an asymmetric chain carbonate from a mixture of different dialkyl carbonates by distillation. However, a strong base such as an alkali metal alcoholate has a drawback that it is difficult to handle and store, for example, it is greatly damaged when it adheres to the human body, has a hygroscopic property, and deteriorates when water is mixed therein. In addition, when such a homogeneous catalyst is used, complicated work such as extraction is required by adding water to remove the catalyst after the reaction, and a great deal of work is required to remove the water added in the post-treatment. Since it is necessary, it is hard to say that it is an industrially preferable method.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and comprises the step of subjecting two kinds of symmetric linear carbonates to catalytic disproportionation reaction to obtain the desired product from an equilibrium mixture. To provide a heterogeneous catalyst which is stable and highly active and does not dissolve in a reaction product solution, and is a highly selective and simple process for producing the desired asymmetric chain carbonate It is to provide a method.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a method for producing an asymmetric chain carbonate by disproportionating two symmetric chain carbonates in the presence of a catalyst. The present invention provides a method for producing an asymmetric chain carbonate characterized by using a catalyst comprising

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention will be described below in detail. In the method of the present invention, the disproportionation reaction between the two kinds of symmetric chain carbonates proceeds as shown in the following reaction formula (1) in the presence of a catalyst composed of titanium oxide, and the desired asymmetric chain state Carbonate is formed.

[0010]

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(Wherein R ¹ and R ² each represent a different linear, branched or cyclic alkyl group. Examples of the linear alkyl group include a methyl group, an ethyl group, a propyl group and a butyl group. Groups, a pentyl group, a hexyl group, a heptyl group, an octyl group, an alkyl group having 1 to 12 carbon atoms such as a dodecyl group, etc. Examples of the branched alkyl group include an isopropyl group, an isobutyl group, and a sec-butyl group. Tert-butyl group, isoamyl group, tert-amyl group, neopentyl group, isohexyl group, sec-hexyl group, tert-hexyl group, and the cyclic alkyl group includes cyclopropyl group, cyclobutyl group, Cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclododecyl, norbornyl Can be mentioned.

Specific examples of such a symmetric chain carbonate ester of raw materials include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate,
Dibutyl carbonate, dicyclohexyl carbonate and the like can be mentioned. Specific examples of the target asymmetric chain carbonate include ethyl methyl carbonate (EMC), methyl propyl carbonate, ethyl propyl carbonate, butyl methyl carbonate, butyl ethyl carbonate, butyl propyl carbonate, and the like.

[0013] What is used as a raw material depends on the target substance. When the target substance is ethyl methyl carbonate, dimethyl carbonate and diethyl carbonate are used as raw materials. The catalyst used in the present invention contains titanium oxide as a catalytically active component. Titanium oxide can be produced by, for example, calcining titanium oxalate, acetate, hydroxide, carbonate, or the like in the air, or a commercially available titanium oxide can be used. it can.

The catalyst oxide used in the present invention is preferably porous and has a large specific surface area, since high catalytic activity can be obtained. An oxide having a specific surface area of usually 5 to 500 m ² / g, more preferably 10 to 300 m ² / g is used. When the specific surface area is less than 5 m ² / g, it is not preferable because sufficient catalytic activity cannot be obtained. In addition, the specific surface area is 500
If it exceeds m ² / g, the strength of the catalyst decreases, and a problem occurs in terms of durability.

These oxides are preferably activated by heat treatment in a stream of an inert gas such as nitrogen for the purpose of removing surface adsorbates such as carbon dioxide and moisture before use as a catalyst. . The processing temperature at that time is 100 to 1
It is in the range of 000 ° C, more preferably in the range of 200 to 800 ° C. If the treatment temperature is lower than 100 ° C., the desorption of the adsorbed substance becomes insufficient, which is not preferable. In addition, when the processing temperature is 1
If the temperature exceeds 000 ° C., heat treatment is costly,
It is not preferable because the oxide partially melts and the surface area decreases. The activation treatment time is not particularly limited because it depends on the amount of the surface adsorbate and the treatment temperature.
-10 hours.

There is no particular limitation on the shape of the catalyst, but it is desirable that the catalyst be molded in order to facilitate liquid permeability during the reaction and to facilitate separation of the catalyst after the reaction. The form may be a fine powder of about 100 μm, but it is more preferably formed by a general method such as granulation and tableting. In preparing the catalyst, a suitable binder may be used. The binder is used for binding the oxide solid of the catalyst to enhance the mechanical strength of the catalyst,
The titanium oxide according to the present invention may not impair the catalytic activity or may exhibit a certain degree of catalytic activity for the reaction, and may be either an inorganic substance or an organic substance. Specific examples of such a binder include silica sol, alumina sol, zirconia sol, and organic polymers.

In preparing the catalyst used in the present invention, a suitable carrier may be used. The carrier can be a high surface area catalyst by dispersing titanium oxide on its surface,
It is used for the purpose of increasing the mechanical strength of the catalyst. The carrier is not particularly limited as long as it does not inhibit the reaction or inhibit the catalytic activity of the titanium oxide, and the carrier may exhibit a certain degree of catalytic activity for the reaction. Specific examples of the carrier include, but are not particularly limited to, silica, alumina, zirconia, silica-alumina, inorganic carriers such as silica-zirconia, kaolinite kaolinite, dickite, halloysite, and smectite montmorillonite, beidellite, and the like. And clay compounds such as hydrotalcite and talc, as well as muscovite muscovite, paragonite, phlogopite and biotite.

[0018] Two kinds of symmetrical chain carbonates as starting materials
The molar ratio of the
Asymmetric chain carbonate intended for use in
It is preferable from the viewpoint of increasing the yield of. But either one
Of course, there is no particular problem even if the reaction is
Preferably, it is selected in the range of 1: 1 to 1:20. S
The temperature of the tellurium exchange reaction is not particularly limited.
In an active gas atmosphere, usually in the range of 0 to 300 ° C.,
Alternatively, the reaction is carried out in the range of 50 to 200 ° C. Reaction temperature
When the reaction rate is low, the reaction speed decreases.
Both are not preferred because the response increases. Also, the reaction pressure
Is not particularly limited, and is 0.1 to 100 kg / cm.^Two-G
Although it can be made to react in the range, usually 0-50 kg /
cm ^Two-G, preferably 0 to 10 kg / cm^Two
Perform in the range of -G.

In the present invention, the method of disproportionating a symmetric chain carbonate ester in the presence of a catalyst may be a batch reaction or a flow reaction, and is not particularly limited. The flow-type reaction is a more economically preferable reaction method because a large amount of the raw material can be continuously processed and the catalyst can be repeatedly used for a long time. The amount of the catalyst used when performing a batch reaction is in the range of 0.01 to 30% by weight, more preferably 0.1 to 15% by weight, based on the raw material. A batch-type reactor is charged with a predetermined amount of the catalyst of the present invention and a raw material, and is subjected to a disproportionation reaction at a predetermined temperature with stirring, whereby a reaction mixture containing the desired asymmetric chain carbonate is obtained. . At this time, the reaction time varies depending on the reaction temperature and the amount of the catalyst used, but is generally in the range of 0.1 to 100 hours, more preferably 1 to 10 hours.

When a flow-type reaction is carried out, any of a fixed bed system, a fluidized bed system and a stirred tank system can be used. The liquid passing conditions at this time can be in the range of 0.05 to 50 / hr, more preferably 0.1 to 10 / hr, when represented by the liquid hourly space velocity (LHSV) with respect to the catalyst. In the method for producing an asymmetric chain carbonate according to the present invention, the reaction proceeds in a liquid phase. At this time, it is not necessary to use another solvent since the two kinds of symmetric chain carbonates themselves as a solvent play a role of a solvent, and it is preferable not to use it from the viewpoint of easiness of post-treatment. It is a solvent that does not react and may be used if it does not hinder the separation after the reaction. Such solvents include benzene,
Aromatic hydrocarbon solvents such as toluene and xylene, saturated hydrocarbon solvents such as tetralin, unsaturated hydrocarbon solvents,
Examples include ether solvents and amide solvents.

After the reaction, since the catalyst does not elute into the reaction solution, the reaction solution is removed as it is or after a minute amount of fine catalyst powder is removed by filtration or the like.
By a known distillation method such as vacuum distillation and pressure distillation, two kinds of symmetric chain carbonates as raw materials and an asymmetric chain carbonate as a reaction product can be separated. In the distillation for separation, the distillation is carried out in the order of the symmetric chain ester of one of the raw materials, the asymmetric chain carbonate as the target substance, and the other chain carbonate of the raw material in the order of the boiling points. As a second fraction of the desired purity. Here, the symmetric chain carbonate ester having a high boiling point among the raw materials may be distilled off, or may be left in the distillation still and recycled for the reaction. In the method for producing an asymmetric chain carbonate according to the present invention, since there is substantially no symmetric chain carbonate as a raw material and other products of the asymmetric chain carbonate as a product, desired production with high selectivity is achieved. A product can be obtained, and the separated raw material can be recovered and reused.

[0022]

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. Production Example of Catalyst: Production Example 1 9.5 g (0.05 mol) of titanium tetrachloride was added to dilute hydrochloric acid
After dissolving in water, 1,000 ml of water was added, and 295 g of silicon tetrachloride was added dropwise with stirring. After completion of the dropwise addition, 28% aqueous ammonia was added to the solution while stirring the solution vigorously to adjust the pH of the solution to 7.0. After standing overnight, the formed precipitate was filtered, washed thoroughly with pure water, dried in air at 120 ° C. for 12 hours, and calcined at 600 ° C. for 3 hours.
An iO ₂ / SiO ₂ catalyst was obtained. This catalyst is called catalyst (1). The atomic ratio of Ti / Si of the catalyst (1) was 3/97.

Production Example 2 71.6 g (0.38 mol) of titanium tetrachloride was added to 100 m of water.
Then, a solution prepared by dissolving 130.5 g of ammonium sulfate in 200 ml of dilute hydrochloric acid was added, and 4.6 g (0.034 mol) of zinc chloride was further added to 10 m of water with stirring.
The solution dissolved in 1 was added. While vigorously stirring this solution, 28% aqueous ammonia was added to adjust the pH of the solution to 7.0.
Was adjusted. After standing overnight, the formed precipitate was filtered, washed thoroughly with pure water, dried in air at 120 ° C. for 12 hours, and calcined at 300 ° C. for 3 hours to obtain ZnO / TiO _2.
A catalyst was obtained. This catalyst is called catalyst (2). Zn / Ti
Was 7/93.

Example 1 In a stainless steel autoclave equipped with a stirrer having a capacity of 1000 ml, 180.2 g (2.0 ml) of dimethyl carbonate was added.
Mol) and 236.3 g (2.0 mol; molar ratio = 1: 1) of diethyl carbonate and catalyst (1) 3.0
g. Next, the inside of the reactor was purged with nitrogen and the nitrogen pressure was adjusted to 1 kg / cm ² -G.
For 4 hours.

After the completion of the reaction, the reaction mixture was analyzed by gas chromatography. The composition of the resulting reaction mixture was 141.5 g (1.57 mol) of dimethyl carbonate, 89.1 g (0.86 mol) of ethyl methyl carbonate, and diethyl carbonate. No other products were found at 201.1 g (1.57 mol). The yield of ethyl methyl carbonate based on the total charged carbonate was 21.4%.

Example 2 The same operation as in Example 1 was carried out except that 3.0 g of the catalyst (2) was used instead of the catalyst (1). The composition of the resulting reaction mixture was dimethyl carbonate 10
1.8 g (1.13 mol), 181.1 g (1.74 mol) of ethyl methyl carbonate and 133.5 g (1.13 mol) of diethyl carbonate showed no other products. The yield based on the total charged carbonate of ethyl methyl carbonate was 43.5%.

Example 3 The same as Example 1 except that 3.0 g of a commercially available silica-titania solid acid catalyst (F-305 manufactured by Fuji Silysia, Ti content: 4% by weight) was used as a catalyst instead of the catalyst (1). Was performed. The composition of the resulting reaction mixture was 162.2 g (1.80 mol) of dimethyl carbonate and 40.6 g (0.39 mol) of ethyl methyl carbonate.
Mol), 212.6 g of diethyl carbonate (1.80)
Mol), no other products were found. The yield of ethyl methyl carbonate based on the total charged carbonate was 9.7%.

Example 4 The same operation as in Example 1 was carried out except that 3.0 g of commercially available titanium dioxide (amorphous, 99.9%, manufactured by Wako Pure Chemical Industries) was used as a catalyst instead of the catalyst (1). . The resulting reaction mixture was composed of 146.9 g (1.63 mol) of dimethyl carbonate, 76.6 g (0.74 mol) of ethyl methyl carbonate, and 192.5 g (1.63 mol) of diethyl carbonate. No product was found. The yield of ethyl methyl carbonate relative to the total charged carbonate was 18.4%.

[0029]

According to the method of the present invention, a solid and highly active titanium oxide is used as a catalyst for the disproportionation reaction of a symmetrical chain carbonate, so that the catalyst itself is free from deterioration due to moisture absorption and can be stored and handled. The process for producing an asymmetric chain carbonate can be easily and simply made without using dangerous substances as raw materials. Further, according to the process for producing an asymmetric chain carbonate ester of the present invention, the post-reaction catalyst and the reaction product can be easily separated, and the post-reaction treatment can be simplified. Further, according to the present invention, by using such a catalyst, a reaction having high selectivity and no reaction by-product can be performed.

Claims (3)

[Claims] 1. A process for producing an asymmetric chain carbonate by disproportionating two chain carbonates in the presence of a catalyst, wherein a catalyst containing titanium oxide as a catalytically active component is used. A method for producing an asymmetric chain carbonate, which is characterized in that: 2. The method according to claim 1, wherein the chain carbonate is dimethyl carbonate and diethyl carbonate, and the target substance is ethyl methyl carbonate. 3. The titanium oxide has a specific surface area of 5 to 500 m.
The production method according to claim 1, wherein the production method is a ² / g porous body.