JP2001247520A - Method of producing carbonate compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing a desired carbonate compound in a high selectivity without causing problems of environmental contamination and without passing through complex steps. SOLUTION: This method of producing a carbonate compound comprises carrying out transesterification between a cyclic carbonate compound and/or noncyclic carbonate compound and a monovalent hydroxyl group-containing compound in the presence of a salt of a metal element selected from IA group, IIA group, IIB group and IIIA group in carbon dioxide in supercritical and/or subcritical state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a novel method for producing an acyclic carbonate compound. More specifically, by performing a transesterification reaction with a monovalent hydroxyl group-containing compound in the presence of a catalyst containing a specific metal salt in supercritical and / or subcritical carbon dioxide, a structure different from that of the raw material carbonate is obtained. The present invention relates to a technology for producing carbonates.

[0002]

2. Description of the Related Art Most carbonate compounds are produced by a dehydrochlorination reaction between phosgene and an alcohol, a dehydrochlorination reaction between a chloroformate ester and an alcohol, or a reaction between an alcohol, carbon monoxide and oxygen (or nitrogen monoxide). Have been. Since chloroformates are also produced using phosgene as a raw material, industrial mass production using compounds such as phosgene and carbon monoxide poses a problem from the viewpoint of environmental measures. As a method for producing acyclic carbonates without using toxic substances such as phosgene and carbon monoxide, a transesterification reaction is known. In this method, alcohols and cyclic or acyclic carbonates are exchanged with alcohols by a transesterification reaction using sodium methoxide or sodium hydroxide as a catalyst, and the carbonates and alcohols are brought into a thermal equilibrium composition, and Symmetric or asymmetric carbonates are separated by means such as distillation.

[0003]

However, this method has the disadvantage that the reaction is very slow for industrial implementation, and that a large amount of catalyst must be used and the reaction temperature must be raised. Further, conventionally known catalysts have a disadvantage that they have a large hygroscopicity and their activity is rapidly reduced when water is mixed into the reaction system. Further, carbonates generally have high hygroscopicity by themselves, and in many cases, oil-water separation becomes difficult in the extraction treatment of catalyst residue with water. There is also a method of adding an extraction solvent to smoothly perform oil-water separation, but adding another solvent as an auxiliary material causes a problem of complicating the production process. An object of the present invention is to provide a method for producing a target acyclic carbonate which is easy to produce and work up and has high selectivity by using a catalyst having a sufficiently large activity.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above problems, and as a result, using carbon dioxide in a supercritical and / or subcritical state in the presence of a specific metal salt. Carbon dioxide acts as a very good reaction medium, and in supercritical and / or subcritical conditions, the solvation of the catalyst is lost or reduced, so the transesterification reaction rate is very high and the selectivity is extremely high. The present invention was found to be higher, and the present invention was completed.
That is, the present invention provides a method for preparing a cyclic carbonate compound and / or a supercritical and / or subcritical carbon dioxide in the presence of a salt of a metal element selected from Groups IA, IIA, IIB and IIIA of the periodic table. Alternatively, a non-cyclic carbonate compound is subjected to a transesterification reaction with a hydroxyl group-containing compound represented by the general formula R ² OH (where R ² represents a hydrocarbon group having 1 to 15 carbon atoms or a substituted hydrocarbon group), and the carbonate is subjected to transesterification. The present invention relates to a method for producing an acyclic carbonate compound, which comprises producing a carbonate compound having a structure different from that of a compound.

In the present invention, carbon dioxide is 304.5.
K, becomes a supercritical state at a relatively low temperature and pressure of 7.387 MPa, does not show any specific interaction with the substrate, and can be removed as a gas by returning to normal pressure, so that it is very useful as a reaction medium. It can be preferably used. In such a reaction field, the reactivity and selectivity are very high,
When carbonates are produced by transesterification by this method, the reactor does not necessarily have to be large-sized, and has many advantages such as harmful waste is not discharged.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The production method of the present invention will be described below in detail. The production method of the present invention, as described above,
In supercritical and / or subcritical carbon dioxide,
In the presence of a specific metal salt, a cyclic carbonate compound and / or an acyclic carbonate compound are combined with a general formula R ² OH
, Ie, an organic compound having a monovalent hydroxyl group, is subjected to a transesterification reaction to obtain a carbonate compound having a structure different from that of the carbonate compound. The transesterification reaction between the acyclic carbonate and the monovalent hydroxyl group-containing compound proceeds, for example, in the following two steps (formula (I) and formula (II)).

[0007]

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(Wherein R ¹ and R ² represent an organic residue selected from a hydrocarbon group having 1 to 15 carbon atoms or a substituted hydrocarbon residue, and R ² and R ¹ are not the same.) Also reacts essentially in the same manner as the acyclic carbonate described above. For example, transesterification of a five-membered ring carbonate proceeds according to formulas (III) and (IV), and cyclic carbonates obtained from higher cyclic ethers proceed according to formulas (V) and (VI). .

[0009]

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[0010]

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(Wherein R ³ , R ⁴ , R ⁵ and R ⁶ each represent hydrogen, a hydrocarbon group having 1 to 15 carbon atoms or a substituted hydrocarbon group, and they may be the same or different, R ³ , R ⁴ , R ⁵ and R ⁶ may be bonded to each other to form a ring, wherein each ring forms a ring via a heteroatom such as oxygen, sulfur or nitrogen. May be.)

[0012]

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[0013]

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[0014] (wherein, m is 0 or 1, n is 3 to 10 integer, R ⁷ represents a hydrocarbon group or substituted hydrocarbon group having 1 to 15 carbon atoms. However R ⁷ are all to form a ring Need not be bonded to the carbon of R. R ² is the same as shown in Schemes (I) and (II).)

More specifically, the above formulas (I) to (VI)
In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶
And the hydrocarbon group or substituted hydrocarbon group represented by R ⁷ , first has 1 to 15 carbon atoms, preferably 1 to 15 carbon atoms.
8 are mentioned. Examples of such hydrocarbon groups include aliphatic, alicyclic, and aromatic hydrocarbon groups.
Examples include an alkyl group, an aryl group, an alkenyl group, a cycloalkyl group, and an aralkyl group. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, and an isobutyl group. Groups, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group and the like. Examples of the aryl group include phenyl group, o-, m-, p-tolyl group, α-, β-naphthyl Groups, and the like. Examples of the alkenyl group include a vinyl group, a propenyl group, an allyl group,
As a cycloalkyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, a norbornenyl group, a cyclododecyl group, and the like are exemplified as a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a glycidyl group, and an aralkyl group. Examples include a benzyl group.

The substituent in the substituted hydrocarbon group includes a halogen, an amino group, a nitro group, a carbonyl group,
Examples thereof include a carboxyl group, an alkoxy group, an acetoxy group, a hydroxyl group, a mercapto group, and a sulfone group. In addition, the above-mentioned thing is mentioned as a hydrocarbon group used as a base of a substituted hydrocarbon group, and as a carbon number, usually 15 or less,
Preferably, it is 12 or less.

When the substituent is halogen, the substituents are fluorine, chlorine and bromine. When the substituent is amino, the substituents are amino, methylamino, dimethylamino, ethylamino, Diethylamino group, N
-Phenylamino group, N-methyl-N-phenylamino group, N-ethyl-N-phenyl-amino group, N-phenyl-Ni-propylamino group, ethanolamino group,
Examples thereof include a diethanolamino group and a morpholyl group. As a carbonyl group, an acetyl group, a propionyl group, a benzoyl group, as a carboxyl group, an acetoxyl group, a propionyloxy group, a benzoyloxy group, and the like; as an alkoxy group, a methoxy group, an ethoxy group,
Examples include a propoxy group, a butoxy group, a pentoxy group, a phenoxy group, and a naphthoxy group. The number of substituents is appropriately selected depending on the hydrocarbon group serving as a base, and is not particularly limited.

Examples of the carbonate represented by the formula (I) include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, diisobutyl carbonate, dicyclohexyl carbonate, diphenyl carbonate, di-p-tolyl carbonate, (2-methoxyethyl) carbonate and the like.

Specific examples of the cyclic carbonate represented by the general formulas (III) and (V) include ethylene carbonate, propylene carbonate, 1,2-, 2,3-
Butylene carbonate, isobutylene carbonate,
1,2-, 2,3-pentene carbonate, 1,2-,
2,3-, 3,4-hexene carbonate, 1,2-,
2,3-, 3,4-heptene carbonate, 1,2-,
2,3-, 3,4-, 4,5-octene carbonate,
1,2-, 2,3-, 3,4-, 4,5-nonene carbonate, cyclopentyl ethylene carbonate, 1,1
-, 1,2-biscyclopentyl ethylene carbonate, cyclhexyl ethylene carbonate, 1,1-,
1,2-biscyclohexylethylene carbonate, styrene carbonate, stilbene carbonate, cyclopentene carbonate, 1-methylcyclopentene carbonate, 1,2-dimethylcyclopentene carbonate, cyclohexene carbonate, 1-methylcyclohexene carbonate, 1,2-dimethylcyclohexene carbonate, cyclo Octene carbonate, 1-methylcyclooctene carbonate, 1,2-dimethylcyclooctene carbonate, 1,5-cyclooctadiene dicarbonate, norbornene carbonate, norbornadiene dicarbonate, vinyl norbornene dicarbonate, ethylidene norbornene dicarbonate, vinyl cyclohexene dicarbonate , Tetrahydroindene dicarbonate Dicyclopentadiene carbonate, 4-hydroxymethyl-1,3-dioxolane -2
-One, ((1,3-dioxolan-2-one) yl)
Methyl butyrate, ((1,3-dioxolan-2-one) yl) methyl methacrylate, ((1,3-dioxolan-2-one) yl) methyl isopropyl ether, ((1,3-dioxolan-2-one) ) Yl) methyl-1-naphthyl ether, bis (((1,3-dioxolan-2-one) yl) methyl) ether, 1,3-
Dioxan-2-one, 4,5-bis (fluoromethyl) 1,3-dioxan-2-one, 5,5-bis (fluoromethyl) -1,3-dioxan-2-one, 4,
4,5,5-tetrafluoro-1,3-dioxane-2
-One, 4,5-bis (chloromethyl) -1,3-dioxan-2-one, 5,5-bis (chloromethyl)-
1,3-dioxan-2-one, 5-chloro-1,3-
Dioxan-2-one, 5-chloromethyl-1,3-dioxan-2-one, 5- (chloromethyl) -5-methyl-1,3-dioxan-2-one, 4,4-bis (4
-Chlorophenyl) -5,5,6-trimethyl-1,3
-Dioxan-2-one, 4,5-bis (bromomethyl) -1,3-dioxan-2-one, 5,5-bis (bromomethyl) -1,3-dioxan-2-one, 5
-Bromomethyl-5-methyl-1,3-dioxane-2
-One, 5-[[6-bromohexyl] oxy] methyl] -5-methyl-1,3-dioxan-2-one, 5
-Bromo-4,5,5-trifluoro-1,3-dioxan-2-one,

5,5-bis (iodomethyl) -1,3-
Dioxan-2-one, 4-methyl-1,3-dioxan-2-one, 5-methyl-1,3-dioxan-2-
On, 4,4-dimethyl-1,3-dioxan-2-one, 4,5-dimethyl-1,3-dioxan-2-one, 4,6-dimethyl-1,3-dioxan-2-one, 5,5-dimethyl-1,3-dioxan-2-one, 5,5-diethyl-1,3-dioxan-2-one, 4-ethenyl-1,3-dioxan-2-one,
-Ethenyl-4-methyl-1,3-dioxan-2-one, 4- (3-butenyl) -1,3-dioxan-2-
On, 4-phenyl-1,3-dioxan-2-one,
5- (methoxymethyl) -5-methyl-1,3-dioxan-2-one, 5,5-bis (ethoxymethyl)-
1,3-dioxan-2-one, 3-methyl-3-hydroxymethyl-1,3-dioxan-2-one, 4-hydroxymethyl-1,3-dioxan-2-one, 5-
Hydroxymethyl-1,3-dioxan-2-one,
4,5-bis (hydroxymethyl) -1,3-dioxan-2-one, 5,5-bis (hydroxymethyl)-
1,3-dioxan-2-one, 4,5-bis (hydroxy) -1,3-dioxan-2-one, 4,6-bis (hydroxymethyl) -1,3-dioxan-2-one, 5 -Hydroxy-1,3-dioxan-2-one,
4,4-dimethyl-5-hydroxy-1,3-dioxan-2-one, 4,5-diphenyl-5-hydroxy-
1,3-dioxan-2-one, (4- (1,3-dioxan-2-one) yl) -5-pentanoic acid,

(5- (1,3-dioxan-2-one)
Yl) -7-heptanoic acid, 1,3-dioxepane-2-
On, 4-methyl-1,3-dioxepan-2-one,
5-methyl-1,3-dioxepan-2-one, 4,7
-Dimethyl-1,3-dioxepan-2-one, 4,
4,7,7-tetramethyl-1,3-dioxepane-2
-One, 4-methylene-1,3-dioxepan-2-one, 4- (2-propenyl) -1,3-dioxepane-
2-one, 4-phenyl-1,3-dioxepane-2-
On, 5-methyl-4- (3-methyl-1,3-butadienyl) -1,3-dioxepan-2-one, 4,7-
Bis (iodomethyl) -1,3-dioxepan-2-one, 4-methoxymethyl-1,3-dioxepan-2-
On, 4-methoxy-1,3-dioxepan-2-one, 4,7-dimethoxy-1,3-dioxepan-2-
On, 4,7-bis (3,4,5-trimethoxyphenyl) -1,3-dioxepan-2-one, 4,7-dimethoxy-1,3-dioxepan-2-one, 5,6-dimethoxy -1,3-dioxepan-2-one, 4-propionyl-1,3-dioxepan-2-one, 1,3-
Dioxocan-2-one, 1,3-dioxonan-2-
On, 4-chloromethyl-1,3-dioxonan-2-
On, 6-chloro-9-methyl-4- (1-methylethyl) -1,3-dioxonan-2-one, 6-chloro-
4-methyl-9- (2-phenylethyl) -1,3-dioxonan-2-one, 5-ethylidene-4-methyl-
1,3-dioxonan-2-one, 4-phenyl-1,
3-dioxonan-2-one, 6-methyl-4- (3-
Methyl-1,3-butadienyl) -1,3-dioxonan-2-one, 4-hexyl-9-propyl-1,3-
Dioxonan-2-one, 4- (1,3-dioxonan-2-one) -ylacetic acid, 4- (1,3-dioxonan-2-one) -ylethanol, 4- (1,3-dioxonan-2) -One) -ylmethanol, 4-hydroxy-1,3-dioxonan-2-one, 5-hydroxy-
1,3-dioxonan-2-one, 6-hydroxy-
1,3-dioxonan-2-one, 1,3-dioxonan-2,4-dione, 1,3-dioxonan-2,5-
Dione, 1,3-dioxonan-2,6-dione, 1,
3-dioxo-4,6-dien-nan-2-one, 1,
3-dioxecan-2-one and the like. Also,
The alkylene moiety may have a branch.

In the production method of the present invention, a cyclic and / or acyclic carbonate compound and a monovalent hydroxyl group-containing compound are mixed in supercritical and / or subcritical carbon dioxide to form a group IA, IIA, IIB and I
The reaction is carried out using a salt of an element selected from Group IIA as a catalyst. Elements in this salt include lithium, sodium, potassium, cesium, rubidium, beryllium,
Magnesium, calcium, strontium, barium, boron, aluminum, gallium, indium and the like, among which alkali metals exemplified by lithium, sodium, potassium and the like, alkaline earths exemplified by magnesium, calcium, strontium, barium and the like The metals and the aluminum family exemplified by boron, aluminum and the like are desirable.

The salts include fluoride, chloride,
Bromide, iodide, sulfate, phosphate, carbonate, acetate,
Organic acid salts such as propionate and butyrate, and sulfonates such as p-toluenesulfonate and trifluoromethanesulfonate. These may partially form a salt, and furthermore, a hydrated metal salt containing one to several tens of crystallization water or structural water per molecule can be used.

Specific examples of the salt include lithium fluoride, lithium chloride, lithium bromide, lithium iodide, lithium sulfate, lithium hydrogen sulfate, trilithium phosphate, dilithium hydrogen phosphate and dihydrogen phosphate. Lithium hydrogen,
Lithium carbonate, lithium hydrogen carbonate, lithium acetate, lithium propionate, lithium butyrate, lithium benzenesulfonate, lithium p-toluenesulfonate, lithium trifluoromethanesulfonate, sodium fluoride, sodium chloride, sodium bromide, sodium iodide, Sodium sulfate, sodium hydrogen sulfate, trisodium phosphate, disodium monohydrogen phosphate, sodium dihydrogen phosphate, sodium carbonate, sodium hydrogen carbonate, sodium acetate, sodium propionate, sodium butyrate, sodium benzenesulfonate, p-toluene Sodium sulfonate, sodium trifluoromethanesulfonate,
Potassium fluoride, potassium chloride, potassium bromide, potassium iodide, potassium sulfate, potassium hydrogen sulfate, tripotassium phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, potassium carbonate, potassium hydrogen carbonate, potassium acetate, Potassium propionate, potassium butyrate, potassium benzenesulfonate, potassium p-toluenesulfonate,
Potassium trifluoromethanesulfonate, magnesium fluoride, magnesium chloride, magnesium bromide, magnesium iodide, magnesium sulfate, magnesium hydrogen sulfate, trimagnesium diphosphate, magnesium monohydrogen phosphate, magnesium carbonate, magnesium hydrogen carbonate, magnesium acetate, Magnesium propionate, magnesium butyrate, magnesium benzenesulfonate, magnesium p-toluenesulfonate, magnesium trifluoromethanesulfonate, calcium fluoride, calcium chloride,
Calcium bromide, calcium iodide, calcium sulfate,
Calcium hydrogen sulfate, tricalcium diphosphate, calcium monohydrogen phosphate, calcium carbonate, calcium hydrogen carbonate, calcium acetate, calcium propionate, calcium butyrate, calcium benzenesulfonate, calcium p-toluenesulfonate, calcium trifluoromethanesulfonate Strontium fluoride, strontium chloride, strontium bromide, strontium iodide, strontium sulfate, strontium hydrogen sulfate, tristrontium diphosphate, strontium monohydrogen phosphate, strontium carbonate, strontium hydrogen carbonate, strontium acetate, strontium propionate, butyric acid Strontium, strontium benzenesulfonate, strontium p-toluenesulfonate, strontium trifluoromethanesulfonate Barium fluoride, barium chloride, barium bromide, barium iodide, barium sulfate, barium hydrogen sulfate, barium diphosphate, barium monohydrogen phosphate, barium carbonate, barium hydrogen carbonate, barium acetate, barium propionate, Barium butyrate, barium benzenesulfonate, barium p-toluenesulfonate,
Barium trifluoromethanesulfonate, boron trifluoride, boron trichloride, boron tribromide, boron triiodide, aluminum fluoride, aluminum chloride, aluminum bromide, aluminum iodide, aluminum sulfate, trialuminum phosphate, aluminum carbonate , Aluminum acetate,
Examples include aluminum propionate, aluminum butyrate, aluminum benzenesulfonate, aluminum p-toluenesulfonate, aluminum trifluoromethanesulfonate, and the like. Of course, two or more of these metal salts may be used in combination.

In the present invention, the activity of these metal salts is not inhibited or the catalytic activity is not reduced. In some cases, the catalytic activity is improved by the synergistic effect with the catalyst component. A carrier supported on any such carrier may be used. Such carriers include boria, silica, alumina, silicon carbide, titania, zirconia, silica-alumina, zirconia-titania, silica-zirconia, alumina-titania, silica-titania, alumina-zirconia, kaolinite, montmorillonite, hydrotalcite , Diatomaceous earth and the like.

Next, the reaction conditions in the production method of the present invention will be described. First, it is essential that the carbon dioxide used in the present invention be in any of supercritical and / or subcritical states. The supercritical state means a condition at or above the supercritical point, that is, a range of a critical temperature of 304.5 K or more and a critical pressure of 7.387 MPa or more, and the subcritical state means a temperature of 293.2 K or more and less than 304.5 K and a pressure of 53.5 K or less. It means a state in the range of 0.066 MPa or more and 7.387 MPa. The transesterification of cyclic and acyclic carbonates in the production method of the present invention is carried out by any of a batch system, a semi-batch system and a continuous flow system.

The reaction state is such that the metal salt acting as a catalyst is
It is preferably carried out in a supercritical and / or subcritical state, and is carried out at a temperature higher than the supercritical point of carbon dioxide, that is, at a critical temperature of 304.5 K or more and a critical pressure of 7.387 MPa or more, Subcritical temperature 293.2K or more and less than 304.5K and pressure 5.066
The reaction may be performed at a pressure of not less than MPa and 7.387 MPa. The reaction temperature is not particularly limited to 293.2K or higher, but preferably is a critical temperature of 304.5K to 573.2K,
More preferably, it is in the range of 373.2K to 473.2K. If the reaction temperature is too low, the reaction rate will be extremely reduced, resulting in an inefficient production method. If the reaction temperature is too high, side reactions will occur at the same time and the selectivity will be reduced, which is not preferable. The reaction pressure is not particularly limited at 5.066 MPa or more, but is preferably 6.078 MPa or more.
30.398 MPa, more preferably a critical pressure of 7.38
The range is from 7 MPa to 15.199 MPa. If the reaction pressure is too low, the reaction rate will be extremely reduced, and it will not be an efficient production method.

In carrying out the present invention, for example, when a batch reaction is carried out, the reaction time is not particularly limited, but is preferably about several seconds to 30 hours, and more preferably 5 minutes to 15 hours. It is about. In addition, when implemented in a continuous flow system, a complete mixing tank,
It is carried out by a method such as a fixed bed or a fluidized bed, but the contact time of the catalyst is not particularly limited, but is preferably about 0.1 second to 10 hours, and more preferably 1 second to 5 hours. If the contact time is too short, the reaction will not proceed sufficiently.

In carrying out the reaction, the charge ratio (molar ratio) of the monovalent hydroxyl group-containing compounds to the cyclic or acyclic carbonate as a raw material is to obtain a mono-substituted product or a di-substituted product as a product. And it is difficult to determine a clear value because it is affected by the reaction temperature and the amount of the catalyst. However, it is usually preferably carried out in the range of 1 to 30, preferably 1 to 10. .

The ratio of supercritical carbon dioxide as a reaction medium is not particularly limited as long as the reaction composition satisfies the condition that the reaction composition is uniform, that is, the condition that the whole system is in a supercritical and / or subcritical state. However, if the amount of carbon dioxide is too large, the selectivity will be high, but the yield will be small and not practical. Therefore, the ratio of supercritical and / or subcritical carbon dioxide in the reaction system is preferably 10 to 90% by volume, preferably 20 to 80%.

The amount of the catalyst used in the present invention is not particularly limited. For example, when the reaction is carried out by a batch reaction or a reaction in a complete mixing tank, the reaction is preferably carried out with respect to the cyclic or acyclic carbonate compound as a raw material.
The ratio of the catalyst salt is usually 0.0001 to 30 mol%,
Preferably it is 0.001 to 20 mol%.

When the above reaction is completed, the unreacted raw materials and the carbonate compound as a product, unreacted and formed alcohol, etc. are usually dissolved in supercritical or subcritical carbon dioxide or undergo phase separation. are doing. In the former case, the carbonate compound or the like is separated from the reaction system by discharging carbon dioxide out of the system during the depressurization and / or cooling process, or by supercritical extraction, or by adding an appropriate medium. Can be.
In the latter case, the carbonate compound and the like can be easily separated by devising a takeout portion. It is also possible to use a method in which an appropriate solvent is present in the reaction system from the beginning to separate a product such as a carbonate compound. The catalyst remaining in the separated product can be separated by ordinary operations such as washing with water, distillation and extraction.
It is also possible to separate by supercritical extraction immediately after the reaction. Since carbon dioxide after the reaction can be separated while maintaining the supercritical state, it can be reused in the reaction as it is.

[0033]

The present invention will be described in more detail with reference to the following examples. However, the present embodiment specifically describes the present invention, and the present invention is not limited to only these embodiments.

Example 1 Lithium bromide 2 as a catalyst was placed in a pressure-resistant reaction vessel having an internal volume of 50 mL.
g, 10 g of dimethyl carbonate and 10 g of anhydrous ethanol were charged, liquid carbon dioxide was injected to 5.1 MPa, and the mixture was reacted at a temperature of 423.1 K for 5 hours. The reaction pressure was 9.4 MPa, and the reaction was performed in a supercritical state although it was a mixed system. After completion of the reaction, the reaction solution is cooled to room temperature,
After the pressure was released, the reaction product was taken out of the reactor and analyzed by gas chromatography, which revealed that DMC ^* / E
MC ^* / DEC ^* = 20/62/18 (molar ratio). * Abbreviations for the following compounds. DMC: dimethyl carbonate EMC: ethyl methyl carbonate DEC: diethyl carbonate

Example 2 The effect of the reaction temperature was examined in the same manner as in Example 1. However, in consideration of the runaway of the reaction at a high temperature, 1 g of lithium bromide was used as the catalyst. The results were as follows. Reaction temperature K DMC / EMC / DEC (molar ratio) 423.1 27/58/15 433.1 24/57/19 443.1 20/53/27

Example 3 A reaction was carried out in the same manner as in Example 1, except that 15 g of ethanol and 5 g of dimethyl carbonate were used. Analysis result DM
C / EMC / DEC (molar ratio) = 4/32/64.

Example 4 The catalyst was changed from 2 g of lithium bromide to 2 g of anhydrous magnesium chloride.
The reaction was carried out in the same manner as in Example 1 except that the reaction was changed to. Analysis result: DMC / EMC / DEC (molar ratio) = 25/5
9/16.

Example 5 A reaction was carried out in exactly the same manner as in Example 1 except that 10 g of n-propanol was used instead of ethanol. The pressure was 8.8 MPa. As a result of analysis, no methyl propyl carbonate was formed, and the product was only dipropyl carbonate. The conversion of dimethyl carbonate was 68.4%.

Example 6 A reaction was carried out in the same manner as in Example 1 except that 10 g of phenol was used instead of ethanol. Analysis results DMC /
MPC ^* / DPC ^* = 40/30/30 (molar ratio). MPC: Methyl phenyl carbonate DPC: Diphenyl carbonate

Example 7 A reaction was carried out in the same manner as in Example 1 except that 10 g of ethylene carbonate was used instead of dimethyl carbonate, and 10 g of methanol was used instead of ethanol. As a result of the analysis, no ethylene carbonate remained, and dimethyl carbonate and ethylene glycol were almost completely formed only by minute amounts of dimethyl ether and diethylene glycol as by-products.

Example 8 A reaction was carried out in the same manner as in Example 7 except that 10 g of propylene carbonate was used instead of ethylene carbonate. As a result of analysis, it was almost completely dimethyl carbonate and propylene glycol in this case as well.

Example 9 In Example 7, phenol was used instead of methanol.
The reaction was carried out using 0 g. As a result of analysis, diphenyl carbonate was produced in a yield of 15%.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C07C 69/96 C07C 69/96

Claims (1)

[Claims] 1. In supercritical and / or subcritical carbon dioxide, the periodic table consists of groups IA, IIA, IIB and
In the presence of a salt of a metal element selected from Group IIIA, a cyclic carbonate compound and / or an acyclic carbonate compound are mixed with a general formula R ² OH (wherein R ² is a hydrocarbon group having 1 to 15 carbon atoms or a substituted hydrocarbon). A non-cyclic carbonate compound having a structure different from that of the carbonate compound by a transesterification reaction with a hydroxyl group-containing compound represented by the following formula: