JPH09110744A - Simultaneous production of dialkyl carbonate and glycol - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a dialkyl carbonate and a glycol simultaneously, efficiently in high yield by transesterifying an alkylene carbonate with an alcohol in the presence of a catalyst. SOLUTION: (A) An alkylene carbonate of formula I [R<1> to R<4> are each H, a (substituted) alkyl, a (substituted) alkenyl, a (substituted) aryl or a cycloalkyl] is transesterified with (B) an alcohol of the formula R<5> OH (R<5> is a 1-12C alkyl, alkenyl, aryl or cycloalkyl) by using (C) a compound selected from alkoxides of rare earth elements of the group IIIB comprising Sc, Y, La and Ac as a catalyst to simultaneously give a dialkyl carbonate of formula II and a glycol of formula III.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for simultaneously producing dialkyl carbonate and glycol. More specifically, the alkylene carbonate and alcohol are transesterified in the presence of a novel catalyst,
The present invention relates to a method for efficiently producing a dialkyl carbonate and a glycol (alkylene diol) at a high yield.

[0002]

2. Description of the Related Art Dialkyl carbonate is a compound useful as a solvent, a gasoline additive, an alkylating agent, an intermediate raw material for polycarbonate, and the like. On the other hand, glycols such as ethylene glycol and propylene glycol are
It is an industrially extremely important compound as a raw material for urethane, a raw material for urethane, an additive, and the like, which are widely used as resins, films, and fibers.

By the way, as a method for producing the above dialkyl carbonate, many methods have heretofore been proposed in which an alkylene carbonate and an alcohol are reacted in the presence of a catalyst to obtain the dialkyl carbonate. The catalysts have transesterification ability, but are classified into homogeneous catalysts and heterogeneous catalysts.

As an example of using a homogeneous catalyst, a method using a tertiary aliphatic amine as a catalyst (Japanese Patent Publication No. 59-2).
No. 8542), a method using an alkali metal or an alkali metal derivative (US Pat. No. 3,642,858, Japanese Patent Publication No. 61-16267), a method using an alkyltin alkoxide (Japanese Patent Publication No. 56-40708), zinc, aluminum, titanium, etc. Of alkoxide (JP-B-60-22697), a method of using a thallium compound (JP-B-60-27658), and a method of using a mixture of a Lewis acid and a nitrogen-containing organic base (JP-B-60-22698).
No.), a method using a phosphine compound (Japanese Patent Publication No. 61-4).
No. 381), or a method using a quaternary phosphonium salt (JP-A-56-10144).

The method using these homogeneous catalysts has an advantage that high activity can be obtained with a small amount of catalyst, but has a drawback that it is difficult to separate the reaction mixture and the catalyst. This transesterification reaction is an equilibrium reaction, and when trying to separate the target dialkyl carbonate and glycol by distillation, the equilibrium shifts during the distillation in the presence of a catalyst, and the reverse reaction easily occurs, and the dialkyl carbonate and glycol are alkylene. The reaction takes place back to the carbonate and alcohol. Moreover, reactions such as dehydration condensation and decomposition occur, which is not preferable in the process.

To prevent this, heterogeneous catalysts have been proposed. In the case of a heterogeneous catalyst, the reaction mixture and the catalyst can be easily separated, and the above-mentioned problems are solved. As an example of using such a heterogeneous catalyst, a method using a silica-titania solid acid catalyst (Japanese Patent Publication No. 61-5467),
A method using an alkali metal or alkaline earth metal silicate-supported catalyst (JP-A-64-31737) and a method using an oxide of zirconium, titanium or tin (JP-A-63).
No. 41432), and a method using a lead compound (Japanese Patent Laid-Open No. 4-143 / 1992).
9356), and a method using a hydrotalcite compound containing magnesia and alumina (JP-A-3-433).
54) or a method using a metal oxide such as zinc oxide (JP-A-6-211751, JP-A-6-239806).
A method using an inorganic solid catalyst such as the above has been proposed.

Further, as a heterogeneous catalyst, a method of using an ion exchange resin (for example, a solid basic anion exchange resin having a quaternary ammonium group or a tertiary amine group) as a catalyst (JP-A-3-109358, JP Kaisho 64-31
737, JP-A-63-238043, JP-B-59-28542), a method using an acidic ion exchange resin as a catalyst (JP-A-64-31737), and a method using a carboxylic acid type cation exchange resin ( JP-A-6-34569
No. 6) is also known.

However, the above-mentioned conventionally known heterogeneous catalysts are generally low in activity, and none of them has reached a practical level in the case of inorganic solid catalysts. Also,
Ion exchange resins show relatively high catalytic activity, but have industrially problematic heat resistance and durability, and lack of catalytic activity in the low temperature range where durability can be maintained. It is left.

[0009]

SUMMARY OF THE INVENTION The main object of the present invention is to provide a novel catalyst which forms a substantially heterogeneous system from compounds that have not been known as catalysts and has a high activity as never before. It is an object of the present invention to provide a method for finding a dialkyl carbonate and a glycol by using the same, which is free from the above-mentioned problems and can be efficiently produced in a high yield. Furthermore, another object of the present invention is to provide a pretreatment method (preparation method) for such a novel catalyst.

[0010]

As a result of intensive studies to solve the above problems, the present inventors have found an excellent new catalyst and reached the present invention. That is, according to the research conducted by the present inventors, in the transesterification reaction of an alkylene carbonate and an alcohol, by using an alkoxide (alkoxy compound) of a rare earth element of Periodic Group 3B as a catalyst, a dialkyl carbonate and a glycol can be efficiently produced. By pretreating the catalyst with the reaction product and / or the product before heating, it becomes a heterogeneous catalyst that is further insoluble in the reaction system and has high catalytic activity, resulting in high yield. A new fact has been found that a dialkyl carbonate and a glycol can be simultaneously produced with high rate and efficiency.

Thus, according to the present invention, the following formula [1]

[0012]

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(In the formula [1], R ¹ , R ² , R ³ and R ⁴
Are the same or different from each other and represent a hydrogen atom, a substituted or unsubstituted alkyl group, an alkenyl group, an aryl group or a cycloalkyl group), and an alkylene carbonate represented by the following formula [2] R ⁵ OH [2] ( In the formula [2], R ⁵ is reacted with an alcohol represented by an alkyl group, an alkenyl group, an aryl group or a cycloalkyl group having 1 to 12 carbon atoms, which may or may not have a side chain, to give a compound represented by the general formula [3]

[0014]

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(In the formula [3], R ⁵ is the same as the above formula [2]), and a dialkyl carbonate represented by the following formula [4]

[0016]

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(In the formula [4], R ¹ , R ² , R ³ and R ⁴
Is the same as the above-mentioned formula [1]), and a alkoxide of a metal selected from scandium, yttrium, lanthanide and actinide selected from the group 3B rare earth elements as a catalyst when simultaneously producing a glycol represented by the formula [1]. There is provided a method characterized in that a compound comprising at least one is used.

The catalyst is preferably a compound containing at least one selected from scandium, yttrium and lanthanide metal alkoxides, and particularly selected from yttrium, lanthanum, cerium, neodinium and samarium alkoxides. Preference is given to using at least one compound or derivatives thereof.

In the above reaction, the alkylene carbonate supplied as the raw material is preferably ethylene carbonate or propylene carbonate, and the alcohol is preferably either methanol or ethanol. Further, the above reaction is preferably carried out under a temperature condition of 40 to 300 ° C.

In particular, in the method of the present invention, as a catalyst, in the pretreatment, the alkoxide of the group 3B rare earth element in the periodic table is a 3-fold or more molar amount of an alcohol of the general formula [2] and / or a product thereof. Which is a product of general formula [4] and / or a reaction product of alkylene carbonate of general formula [1] and / or a product of general formula [3] dialkyl carbonate. It is industrially advantageous to use a special catalyst.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION According to the method of the present invention, the alkylene carbonate represented by the above formula [1] and the alcohol represented by the above formula [2] are subjected to transesterification reaction as described above to obtain the above formula [ 3] and the glycol represented by the above formula [4] are simultaneously produced. In this reaction, the method of the present invention comprises
As a catalyst, the greatest feature is to use a compound containing at least one selected from alkoxides of metals selected from scandium, yttrium, lanthanide, and actinide periodic group 3B (former group IIIA) rare earth elements. To do. At this time, as the pretreatment for the reaction, it is preferable that the above-mentioned alkoxide serving as a catalyst is subjected to a heating treatment in the presence of alcohol and carbonate as a reaction product and / or a product to be used as a catalyst having improved activity and the like.

The alkylene carbonate as one of the starting materials in the method of the present invention is a compound represented by the above formula [1], wherein R ¹ , R ² , R ³ and R ⁴ in the formula [1] are hydrogen atoms, A substituted or unsubstituted alkyl group, alkenyl group,
It is an aryl group or a cycloalkyl group. These may be the same as or different from each other. Specific examples of such alkylene carbonate include ethylene carbonate, propylene carbonate, 1,2-butylene carbonate,
2,3-butylene carbonate, styrene carbonate and the like can be mentioned. Among these, ethylene carbonate or propylene carbonate is most often used because of the usefulness of the desired glycol and industrial availability.

The alcohol, which is the other raw material in the method of the present invention, is represented by the above formula [2], and R ⁵ in the formula [2] has 1 to 10 carbon atoms with or without a side chain. 12 alkyl, alkenyl, aryl or cycloalkyl groups. Specific examples of such alcohol include methyl alcohol, ethyl alcohol, n-propyl alcohol, iso-propyl alcohol, and n-propyl alcohol.
Butyl alcohol, iso-butyl alcohol, sec
-Butyl alcohol, pentyl alcohol, hexyl alcohol, octyl alcohol, 2-ethylhexyl alcohol, decyl alcohol, dodecyl alcohol, allyl alcohol, cyclohexyl alcohol, benzyl alcohol, etc., among which methyl alcohol or ethyl alcohol is most useful Often used in.

In the method of the present invention, the above formula [1]
The alkylene carbonate represented by the formula [2] and the alcohol represented by the formula [2] are subjected to a transesterification reaction in the presence of a specific catalyst to give the above formula according to the stoichiometric formula [5]. The dialkyl carbonate represented by [3] and the glycol represented by the above formula [4] are simultaneously produced.

[0025]

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(R ^{1 to} R ⁵ in the formula [5] are the same as above.)

The novel catalyst used in the method of the present invention comprises a compound containing at least one metal alkoxide selected from the group 3B rare earth elements of scandium, yttrium, lanthanide and actinide. These three
Specific examples of the group B rare earth elements include Sc, Y and lanthanide group La, Ce, Pr, Nd, Sm, Eu, G.
Examples thereof include d, Tb, Dy, Ho, Er, Tm, Yb and Lu, and Ac, Th, Pa and U of the actinide group, and one or more of these 3B group rare earth element alkoxides. The combination is used as a catalyst. Usually, these alkoxides are trivalent, but Ce and P
Some of them, such as r and Tb, are partially tetravalent and some of them are divalent, such as Sm, Eu, and Yb, and both can be used in the method of the present invention. Generally, a trivalent alkoxide is represented by the following formula [6].

Ln (OR ⁶ ) (OR ⁷ ) (OR ⁸ ) ... [6] (In the formula, Ln is scandium, yttrium, lanthanide or actinide, which is a trivalent group 3B metal element,
R ⁶ , R ⁷ and R ⁸ are the same or different from each other.
It is a valent aliphatic hydrocarbon group. )

More specifically, R ⁶ and R ⁷ of the above formula [6] are
And R ⁸ is a linear or branched alkyl group or cycloalkyl group having 1 to 12 carbon atoms, and specific examples of the alkyl group include, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, Butyl group, isobutyl group,
Examples thereof include a tert-butyl group, pentyl group, hexyl group, and octyl group. Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. Further, these hydrocarbon groups may be bonded to each other to form a divalent or trivalent or more cyclic or chain alkoxide. Examples of the polyvalent aliphatic hydrocarbon group include ethylene group, propylene group, butylene group, neopentyl group and the like.

In the above formula [6], the alkoxides of scandium, yttrium, lanthanide and actinide metals are represented in the form of trivalent monomers, but the kind of these metals and the aliphatic hydrocarbon group Depending on the type and combination, a dimer or higher multimer or a mixture of a monomer and a multimer may be formed, and both can be effectively used in the method of the present invention.

Further, even when a part of the alkoxide is replaced with a hydroxyl group or an oxide, it can be used similarly. Although yttrium oxide isopropoxide Y ₅ O (OiPr) ₁₃ is known as such an example, the method of the present invention is not limited to this example.

Scandium (Sc), yttrium (Y) and lanthanide metals (La, Ce, Pr, Nd, S)
m, Eu, Gd, Tb, Dy, Ho, Er, Tm, Y
b, Lu) and actinide metals (Ac, Th, Pa, U
Etc., all of the alkoxides of various metals mentioned above have a high catalytic activity in the present reaction and can be suitably used in the method of the present invention. Among them, Y, La,
The metals belonging to the so-called cerium group of Ce, Pr, Nr, and Sm have a large amount of endowment and are particularly preferably used on an industrial scale.

On the other hand, examples of the alkoxides include alkoxides derived from lower aliphatic monohydric alcohols such as methoxide, ethoxide, propoxide, isopropoxide and butoxide, or lower aliphatic dihydric alcohols such as ethylene glycoside and propylene glycoside. It is preferably used.

The catalyst composed of the alkoxide of the rare earth element of the 3B group is prepared, for example, by the following method: (a) a lanthanide metal and an aliphatic alcohol are heated to reflux without a catalyst or in the presence of a catalyst, and hydrogen is generated. Method,
(B) a method of removing an alkali metal salt produced by causing an alkali metal salt of a lower aliphatic alcohol to act on a salt anhydride such as a lanthanide metal hydrochloride, nitrate or sulfate, (c) a lanthanide metal oxide and an aliphatic salt It can be prepared by a method of observing the formation of a partial alkoxide from an alcohol by a dehydration reaction, and (d) another alkoxide of the lanthanide metal once prepared is reacted with another aliphatic alcohol to give another alkoxide. It can also be derivatized to an alkoxide. If this exchange reaction is utilized, an aromatic monohydroxy compound is caused to act in place of the aliphatic alcohol to induce an alkoxide containing an aromatic hydroxide of lanthanide metal, which is considered to be one of the catalytically active species of this reaction. You can also do it. In the method of the present invention, such an alkoxide containing phenoxide can be effectively used as a catalyst.

Of these catalyst preparation methods, the most economical and simplest method on an industrial scale is the salt of a strong acid of Group 3B metal (such as chloride) and an aliphatic alcohol having 3 to 8 carbon atoms. It is a method of reacting with an alkali metal salt of the above to remove salts that are simultaneously formed. The alkoxide of a 3B group metal derived from an aliphatic alcohol having 3 or more carbon atoms is a hydrocarbon, ester, ketone, higher alcohol, etc. The salt produced at the same time is easily dissolved in a volatile solvent that does not dissolve, so that it is easy to separate from the salt and a highly pure salt is efficiently obtained. Here, as the aliphatic alcohol having 3 to 8 carbon atoms, iso-propyl alcohol,
n-propyl alcohol, n-butyl alcohol, n-
Hexyl alcohol and the like, especially iso-propyl alcohol is most suitable for this purpose, and triisopropoxide is generally used as the alkoxide of the Group 3B metal obtained, and can be easily obtained on an industrial scale.

In the method of the present invention, the above-mentioned Group 3B metal alkoxide used as a catalyst is preferably used as a raw material (reactant) or an alcohol component such as glycol of a product before the reaction, preferably as a raw material or a product. Ligand exchange is preferably carried out in the presence of carbonate to convert the alcohol component into an alkoxide having a part or a majority thereof. At this time, the above 3
The alcohol of the alkoxide component of the Group B metal is liberated. Then, the converted alkoxide has extremely low solubility, and the catalyst is substantially heterogeneous.

Therefore, in the method of the present invention, when methanol or ethanol is used as a raw material alcohol, even if an alkoxide consisting of an alcohol having 3 or more carbon atoms, which is easy to prepare, is used as a catalyst, methoxide or Since it is converted to ethoxide and the catalyst is not substantially dissolved in the reaction system and becomes a heterogeneous system, it can be easily separated from the reaction product and the like, and can be easily recycled and reused.

Thus, in the method of the present invention, the above-mentioned catalyst is preliminarily pretreated, and alcohol and / or
Alternatively, by heating in the presence or absence of the product glycol and the reactant and / or the product carbonate, a catalyst having a substantially heterogeneous system and high reaction activity can be obtained. By using it for the reaction, it becomes possible to obtain the desired dialkyl carbonate and alkylene glycol with high purity particularly efficiently.

The alcohol of the reaction product or glycol of the product in this pretreatment reaction is represented by the above formula [2].
And the one represented by the above formula [4]. When these are added to the above catalyst and subjected to heating treatment, ligand exchange of the alkoxide is caused to cause the catalyst metal to have the alcohol of the above formula [2] or the above formula [4]. Is introduced to liberate the alcohol of the catalyst alkoxide (R ^{6 to} R ^{8 in} the above formula [6]) before the treatment.

The amount of addition is appropriately 3 times mol or more, preferably 5 times mol or more, particularly preferably 10 times mol to 50 times the total amount based on the Group 3B metal alkoxide of the catalyst.
It is twice the mole. If the amount added is too small, ligand exchange will not occur sufficiently, and thus catalyst heterogeneity will be inadequate, and at the same time the product may be contaminated with alcohol other than the reactant liberated from the catalyst before treatment in this reaction. There is.

This pretreatment reaction is preferably carried out in the presence of the alkylene carbonate of the above formula [1] and / or the dialkyl carbonate of the above formula [3] in order to enhance the catalytic activity effect. The amount of these carbonates added is 0.1 to 50 times mol, preferably 1 to mol times.
It is 20 times the molar amount. If the addition amount is small, the catalyst activation effect is small, and if it is too large, the ligand exchange reaction in the pretreatment may be delayed.

The reaction temperature in the pretreatment is 1 at room temperature or higher.
The temperature is 50 ° C or lower, preferably 50 ° C to 120 ° C. Particularly preferably, a temperature around the boiling point of the alcohol used is adopted. If the reaction temperature is low, the reaction rate is slow and the treatment takes too long, which is not preferable, and if it is too high, the catalyst may be deactivated. Although the heating time depends on the treatment temperature, it is usually 0.5 to 3 hours, and particularly preferably 1 to 2.5 hours.

After such pretreatment, it is appropriate to release the catalyst from the reaction treating agent and the alcohols and reaction products liberated by the reaction treatment by a method such as filtration or centrifugation. After removing only alcohols by a method such as evaporation, a mixture of the reaction product and the product used as the reaction treating agent and the heterogenized catalyst may be used as it is.

In the method of the present invention, the above-mentioned novel catalyst is generally used in a catalytic amount to react an alkylene carbonate with an alcohol to simultaneously produce a dialkyl carbonate and an alkylene glycol according to the above formula [5]. be able to. The reaction temperature at this time is 40 to
The temperature is 300 ° C, preferably 50 to 250 ° C. If it is lower than this temperature range, the reaction rate is not sufficient, and if it is higher than this temperature range, side reactions such as decomposition may occur, which is not preferable.

In the method of the present invention, the composition ratio of the raw material alkylene carbonate and alcohol is a reaction stoichiometry in which the molar ratio is 1 for alkylene carbonate and 2 for alcohol, but this reaction is controlled by chemical equilibrium. Therefore, in order to increase the conversion rate of alkylene carbonate, it is preferable to use alcohol in excess. Usually, the alcohol is used in an amount of 2 to 20 mol, more preferably 2 to 10 mol, based on 1 mol of the alkylene carbonate.

When this reaction is carried out in a closed form, or when it is carried out even in an open system with total reflux, the reaction apparently stops when it reaches an equilibrium composition based on the equilibrium constant at the reaction temperature used. Therefore, in order to ultimately proceed the reaction further, it is necessary to separate the catalyst and the reactant from the equilibrium composition and the raw material and the product. Since the catalyst used in the method of the present invention exhibits a substantially heterogeneous system, the catalyst and the reaction product can be separated relatively easily, and the separated catalyst can be reused as it is. The reaction raw materials are separated by a method such as distillation.

[0047]

The present invention will be described below with reference to examples and comparative examples, but it goes without saying that the present invention is not limited to these examples.

Example 1 A flask having a capacity of 100 ml was charged with 17.6 g of ethylene carbonate and 17.3 g of methanol.
0 g was charged, 1.5 g of triisopropoxysamarium: Sm (OiPr) ₃ was added as a catalyst, the temperature of the oil bath was kept at 100 ° C. with stirring, and the reaction was carried out at total reflux for 1.5 hours. After the reaction, the precipitated reaction mixture was removed, and the resulting reaction mixture was subjected to proton H ¹ NMR (nuclear magnetic resonance spectrum).
Was used for quantitative analysis from the peak area ratio of each component.

As a result, the composition of the reaction mixture was as follows: ethylene carbonate 4.52 g, methanol 7.17 g, dimethyl carbonate 12.6 g, ethylene glycol 6.
It was found to be composed of 95 g and 2.36 g of 2-hydroxyethylmethyl carbonate. The conversion based on ethylene carbonate was 74.5%, and the yield of dimethyl carbonate was 70%. In addition, the above-mentioned "2-hydroxyethyl methyl carbonate etc." means that the bis-2-hydroxyethyl carbonate, 1,2-ethanediyl dimethyl carbonate etc. which are equilibrium intermediates are contained in it. .

[Examples 2 to 6, Comparative Examples 1 to 3] Capacity 10
Ethylene carbonate 1 in 0 ml autoclave
7.6 g, 16.0 g of methanol and 1.5 g of the compound shown in Table 1 as a catalyst were added, and the reaction was carried out at 100 ° C. for 2 hours with stirring. After the reaction, the reaction mixture was rapidly cooled, the reaction mixture was immediately taken out, quantitatively analyzed by H ¹ NMR in the same manner as in Example 1, the conversion rate was calculated from the residual amount of ethylene carbonate (EC), and dimethyl carbonate (DMC) and free The amounts of ethylene glycol (EG) produced were compared. Table 1 shows the results.

[0051]

[Table 1]

Example 7 In an autoclave having a volume of 100 ml, 17.6 g of ethylene carbonate, 32.0 g of methanol and 1.5 g of triisopropoxy neodymium: Nd (OiPr) ₃ as a catalyst were charged.
The reaction was carried out by stirring at 0 ° C for 2 hours. After the reaction, the reaction mixture was rapidly cooled, and the reaction mixture was immediately taken out.
Quantitative analysis was carried out by ¹ NMR, the conversion rate was obtained from the remaining amount of ethylene carbonate, and the production amounts of dimethyl carbonate and free ethylene glycol were compared. as a result,
The composition of the reaction mixture was 3.7 g of ethylene carbonate,
Methanol 19.7 g, dimethyl carbonate 13.6
g, 7.5 g of ethylene glycol and 5.1 g of 2-hydroxyethylmethyl carbonate. In this example, the conversion based on ethylene carbonate is 79.
%Met.

Example 8 The catalyst used in Example 7 was filtered from the reaction mixture and then used as is, with a volume of 100.
New ethylene carbonate 1 ml in autoclave
Example 7 was prepared by charging with 7.6 g and 32 g of methanol.
The reaction was carried out in the same manner as described above. As a result, the composition of the reaction mixture was 3.9 g of ethylene carbonate and 19.
It was found to consist of 5 g, 13.7 g of dimethyl carbonate, 7.0 g of ethylene glycol and 5.3 g of 2-hydroxyethyl methyl carbonate. In this example, the conversion rate based on ethylene carbonate was 77%.

Example 9 In a flask having a capacity of 100 ml, 17.6 g of ethylene carbonate and 1.5 g of triisopropoxysamarium: Sm (OiPr) ₃ as a catalyst were placed, and methanol was supplied at a rate of about 25 g / hr. On the other hand, the temperature of the oil bath was maintained at 100 ° C., and the low boiling point evaporate was collected and reacted for 2 and a half hours. As a result of quantitative analysis of the collected fractions and the reaction mixture remaining in the flask using gas chromatography, the low boiling point effluent was composed of 15.8 g of dimethyl carbonate and 53.6 g of methanol,
0.6g of dimethyl carbonate in the flask residue
And 2.1 g of methanol were found to be contained. The conversion based on ethylene carbonate in this example was 92.
9%.

Example 10 (Catalyst pretreatment) A three-neck flask having a capacity of 200 ml was equipped with a condenser, and triisopropoxysamarium: Sm was added.
(OiPr) ₃ (4.0 g), methanol (6.4 g) and ethylene carbonate (44.0 g) were added, and the mixture was refluxed for about 1 hour. The temperature after the reaction initially rose from 68 ° C to 73 ° C. After standing to cool, the reaction mixture of the pretreatment and the catalyst were separated by decantation. As a result of analyzing the reaction mixture obtained by this pretreatment by gas chromatography, 43.2 g of methanol, 13.1 g of ethylene carbonate, 26.9 g of dimethyl carbonate and 1 of ethylene glycol were obtained.
It contained 6.6 g, 1.8 g of isopropanol and a trace amount of methyl isopropyl carbonate.

(Reaction of Methanol with Ethylene Carbonate) Using the catalyst pretreated as described above, the same 2
New methanol 64.0 in the 00 ml condenser.
g and 44.0 g of ethylene carbonate were added, and the mixture was refluxed for about 1 hour. As a result of analyzing the obtained reaction mixture by gas chromatography, methanol 45.7 g, ethylene carbonate 13.1 g, dimethyl carbonate 26.8
g, ethylene glycol 16.5 g were contained, and isopropanol was not detected.

Example 11 (Catalyst pretreatment) 1.5 g of tripropoxylanthanum was placed in a 100 ml capacity flask equipped with a condenser.
32.0 g of methanol and 17.6 g of ethylene carbonate were added, and the mixture was heated under reflux for 1 hour under normal pressure in the same manner as in Example 1. After this pretreatment reaction, the mixture was allowed to stand and cool, the catalyst was decanted and separated from the reaction mixture obtained by the pretreatment, and the catalyst was washed with a small amount of methanol and vacuum dried.

(Reaction of methanol and ethylene carbonate) Using 1.44 g of the catalyst pretreated as described above,
Add 3 freshly in a 100 ml flask equipped with a condenser.
2.0 g of methanol and 17.6 g of ethylene carbonate were added, and the mixture was heated under reflux for about 1 hour. When the obtained reaction mixture was analyzed by gas chromatography, it was confirmed that 12.5 g of dimethyl carbonate and 7.6 g of ethylene glycol were produced.

[Example 12] (Catalyst pretreatment) Triisopropoxy neodymium: Nd
1.5 g of (OiPr) ₃ was taken, and heated and refluxed with 20.0 g of methanol and 2.0 g of dimethyl carbonate in a 100 ml flask for about 1 hour. Most of the low-boiling-point reactants and liberated isopropanol used before the treatment were removed by decantation, and the mixture was further heated under vacuum to be evaporated.

(Reaction of methanol with ethylene carbonate) Next, 32.0 g of methanol and 17.6 g of ethylene carbonate were added to the flask containing the catalyst, and the mixture was heated under reflux for about 1 hour. The temperature of the reaction solution is about 70
° C. As a result of analyzing the obtained reaction mixture by gas chromatography, 8.9 g of dimethyl carbonate,
It was confirmed that 6.1 g of ethylene glycol, 20.0 g of methanol and 3.9 g of ethylene carbonate were contained.

Example 13 (Catalyst pretreatment) In the same manner as in Example 12, 1.5 g of triisopropoxy neodymium: Nd (OiPr) ₃ was used,
As a pretreatment, this was treated with 20.0 g of methanol, 5.0
g of ethylene glycol and 2.0 g of a dimethyl carbonate mixed solution, and the mixture was refluxed and stirred for 1 hour.
The low boiling point compounds were removed by vacuum distillation to obtain a pretreated catalyst.

(Reaction of Methanol and Ethylene Carbonate) In the same manner as in Example 12, the pretreatment catalyst was mixed with 1
7.6 g of ethylene carbonate and 32.0 g of methanol were added, and the mixture was stirred under reflux at normal pressure for 1 hour. In the reaction mixture, 9.3 g of dimethyl carbonate, 10.1 g of ethylene glycol and 5.6 g of ethylene carbonate.
And 24.1 g of methanol were confirmed to be contained.

[0063]

According to the method of the present invention as described above, alkylene carbonates such as ethylene carbonate and propylene carbonate are efficiently reacted with alcohols such as methanol and ethanol to give dialkyl carbonate and ethylene glycol in a high yield. Can be manufactured in.

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Claims (8)

[Claims] 1. The following formula [1]: (In the formula [1], R ¹ , R ² , R ³ and R ⁴ are the same or different from each other and represent a hydrogen atom, a substituted or unsubstituted alkyl group, an alkenyl group, an aryl group or a cycloalkyl group). An alkylene carbonate shown,
Formula [2] R ⁵ OH [2] (In the formula [2], R ⁵ represents an alkyl group having 1 to 12 carbon atoms, an alkenyl group, an aryl group or a cycloalkyl group having or not having a side chain. ) Is reacted with an alcohol represented by the following formula [3] (In the formula [3], R ⁵ is the same as the above formula [2]), and a dialkyl carbonate represented by the following formula [4]: (In the formula [4], R ¹ , R ² , R ³ and R ⁴ are the same as those in the above formula [1]) and a glycol which is simultaneously produced in the method of producing scandium as a catalyst,
3B consisting of yttrium, lanthanide and actinide
A method for producing, characterized in that a compound containing at least one selected from alkoxides of group rare earth elements is used. 2. The method according to claim 1, wherein a compound containing at least one selected from scandium, yttrium, and lanthanide metal alkoxides is used as a catalyst. 3. The catalyst, yttrium, lanthanum,
The method according to claim 1, wherein at least one compound selected from alkoxides of cerium, neodinium and samarium is used. 4. The production method according to claim 1, wherein the reaction is performed under a temperature condition of 40 to 300 ° C. 5. The production method according to any one of claims 1 to 4, wherein ethylene carbonate or propylene carbonate is used as the alkylene carbonate. 6. Methanol or methanol is used as the alcohol, wherein the alcohol is used.
The production method according to any one of the above. 7. As a catalyst, the alkoxide of a rare earth element of Group 3B is heated with 3 times or more moles of the alcohol of the formula [2] which is a reactant and / or the glycol of the formula [4] which is a product. The production method according to claim 1, wherein a catalyst pretreated by the treatment is used. 8. In the pretreatment of the catalyst, heat treatment is carried out in the presence of a alkylene carbonate of the formula [1] which is a reactant and / or a dialkyl carbonate of the formula [3] which is a product. The manufacturing method according to claim 7.