JPH0355472B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an organic carbonate by subjecting a specific epoxy compound to a heating reaction with carbon dioxide in the presence of a specific catalyst. Many reaction catalysts have been proposed and known in the production of organic carbonates by reacting epoxy compounds with carbon dioxide. In all of these prior examples, the reaction temperature was approximately
Not only does it require a temperature of 150°C or higher and a reaction pressure of 100 atm or higher, but even with such extreme reaction conditions, the yield of organic carbonate relative to the epoxy compound is satisfactorily high. However, there were difficulties in industrializing it. In order to solve this difficulty, the present inventors previously proposed a composite catalyst consisting of a Lewis acid and a nitrogen-containing organic base. (Refer to Japanese Patent Publication No. 48-27314) Although the above-mentioned drawbacks can be solved in the reaction of ethylene oxide or propylene oxide with carbon dioxide, the present inventors' According to studies, it has been found that all of the catalysts disclosed in the above-mentioned publication are not necessarily effective in the reaction between epoxy compounds having 4 or more carbon atoms and carbon dioxide. Furthermore, since the proposal shown in the above-mentioned publication, many new catalysts for producing organic carbonates using epoxy compounds and carbon dioxide have been proposed (Japanese Patent Application Laid-open Nos. 51-19722, 1972-1972, and 51-1972).
-118763, etc.) However, even if the catalysts specifically shown in these are used, if an epoxy compound having 4 or more carbon atoms is used as a raw material, the yield, selectivity, etc. of the corresponding organic carbonate will be low. All I could get was unsatisfactory results. Considering the above-mentioned circumstances, the present inventors produced the corresponding organic carbonate from an epoxy compound having 4 or more carbon atoms constituting the molecule and carbon dioxide in a high yield and with a high selectivity to the raw material epoxy compound. As a result of careful consideration, we decided to
The present inventors discovered that good results could be obtained by using a combination of a specific Lewis acid and a specific nitrogen-containing organic base, which were not specifically disclosed in Publication No. 48-27314, as a catalyst, and arrived at the present invention. . That is,
In the present invention, in the presence of at least one compound selected from the following compound group (1) and at least one compound selected from the compound group (2), carbon dioxide and a molecule having 4 or more carbon atoms. This is a method for producing an organic carbonate characterized by reacting it with an epoxy compound. (1) A group of alkoxide compounds of iron, aluminum, zinc, titanium, tin or antimony that are bonded to at least one halogen atom. (2) A group of compounds consisting of pyridine, quinoline, isoquinoline, or derivatives thereof. In carrying out the method of the present invention, the epoxy compound which is one of the raw materials used is, as mentioned above, an epoxy compound having 4 or more carbon atoms in its molecule, and is an epoxy compound represented by the following general formula. be. Here, R ₁ represents a hydrogen atom or a methyl group, and R ₂
represents a methyl group, an ethyl group or a phenyl group. Examples of these epoxy compounds include isobutylene oxide (1,1-dimethylethylene oxide), 1,2-butylene oxide, styrene oxide, and α-methylstyrene oxide. Specifically, the alkoxide compounds shown in the above-mentioned group (1) constituting the catalyst used in carrying out the method of the present invention include iron, aluminum, zinc,
It is an alkoxide compound of titanium, tin or antimony, and at least one atom of these metals.
It is an alkoxide compound in which halogen atoms are bonded. The alcohol residue of this alkoxide group is generally a lower alkyl group, such as methyl, ethyl, n-butyl, isobutyl, eec-butyl, tert-butyl and the like. Moreover, the above-mentioned halogen atom is specifically chlorine, bromine, or iodine. These alkoxide compounds can be produced by a known method such as condensation of a corresponding metal halide and an alkali metal alcoholate. These compounds include, for example, ClAl(OR) ₂ , Cl ₂ Al(OR), BrAl(OR) ₂ ,
_Br2Al (OR), IAl(OR) ₂ , ClZn(OR), BrZnOR,
IZnOR, ClFe(OR) ₂ , _Cl2Fe (OR), BrFe
(OR) ₂ , Br ₂ Fe (OR), Cl ₂ Sn (OR) ₂ , Cl ₃ Sn
(OR), Cl ₂ SnR (OR), ClSnR ₂ (OR), ClTi
(OR) ₃ , Cl ₂ Ti (OR) ₂ , Cl ₃ Ti (OR), Cl ₃ Sb
(OR) ₂ , Cl ₂ Sb (OR) ₃ , Cl ₂ SbR ₂ (OR), etc. (However, each R is the same or different alkyl group as described above.) The compounds shown in group (2) are pyridine, quinoline, isoquinoline, or derivatives thereof, and these derivatives include halogen atoms, alkyl groups, alkenyl group, aryl group, aralkyl group,
Derivatives substituted with etc. can be mentioned. Examples of these derivatives of pyridine include methylpyridine, ethylpyridine, vinylpyridine, phenylpyridine, methylethylpyridine, vinylmethylpyridine, chloromethylpyridine, and benzylpyridine. There are no restrictions on the substitution position, but
Preferably, the hydrogen bonded to the carbon atom constituting the ring is substituted. The same applies to quinoline and isoquinoline derivatives as in the case of pyridine. As mentioned above, in the method of the present invention, that is, the method for efficiently producing the corresponding organic carbonate from the above-mentioned specific epoxy compound and carbon dioxide, it is essential that these two types of compounds are present as catalysts. . In the method of the present invention, which requires the presence of the aforementioned catalyst, the reaction temperature can be kept low compared to conventional techniques, and is generally 70 to 200°C, preferably
A sufficient reaction rate can be obtained in the temperature range of 100-150°C. In addition, the reaction pressure may also be relatively low,
A pressure of 80 atm or less is sufficient, and therefore, in the case of a batch reaction, for example, the amount of carbon dioxide to be added in excess can be small. In addition, by combining the raw material epoxy compound and two types of catalysts, it is possible to suppress the reaction pressure to about 50 atmospheres, and it is also possible to simplify the apparatus. The reaction time varies depending on the combination of raw materials and catalyst used, but when performing a batch reaction, it is generally 1
About 3 hours is sufficient, and the reaction may be terminated when the pressure that decreases as the reaction progresses becomes constant. Regarding the molar ratio of the two types of raw materials used in the above reaction, the epoxy compound is Preferably, an excess amount of carbon dioxide is used. Furthermore, regarding the two types of catalysts mentioned above, the molar ratio of the metal alkoxide compound shown in group (1) and the pyridine shown in group (2) is not necessarily limited, but in general, the latter basic substance is used in excess. It is preferable to use it, and good results are obtained when it is used in the range of equimolar or more and 5 times the molar or less. The amount of these catalysts to be used is preferably 0.1 to 10% by weight based on the raw material epoxy compound, and there is no limitation on the method of adding them to the reaction system. Alternatively, each may be added separately to the reaction system. In the method of the present invention, an inert solvent can be used in addition to the above-mentioned raw materials and catalysts, and the use of a solvent is advantageous for facilitating the industrial reaction. However, in consideration of separation of the product after the reaction, etc., it is advantageous to use the organic carbonate as the solvent for the purpose of the method of the present invention. Under the conditions described above, if a batch method is used to carry out the method of the present invention, the specified epoxy compound, carbon dioxide, and catalyst are first put into a pressure reaction vessel together with a solvent as the case may be, and heated. The reaction may be allowed to proceed, and heating may be stopped when the reaction pressure has substantially stopped decreasing to terminate the reaction. Then, if unreacted carbon dioxide remains, it is released from the reaction product, and the desired high-purity organic carbonate can be obtained by distilling the residual liquid, for example. Furthermore, as a matter of course, it is also possible to carry out this reaction in a flow system. As described above, according to the method of the present invention, even if the reaction pressure is lowered at a lower reaction temperature than in the conventional technique, the above-mentioned epoxy compound, which is conventionally difficult to react to a cyclic carbonate, can be converted into a cyclic carbonate. Not only can organic carbonate be easily obtained, but the yield and selectivity of the produced organic carbonate are high, and moreover, a product with high purity, for example, 99% or more, can be easily obtained. The present invention will be further explained in detail with reference to Examples and Comparative Examples below, but the present invention is not limited thereto. In addition, the parts described below indicate parts by weight unless otherwise specified. Example 1 72 parts of isobutylene oxide, 1.2 parts of ClAl(OEt) ₂ (monochloroaluminum diethoxide) and 3.0 parts of pyridine were placed in a stainless steel autoclave, and the autoclave was sealed. Next, 53 parts of carbon dioxide was introduced under pressure, and the mixture was gradually heated with stirring and allowed to react at 150°C for 2 hours. The pressure was 50 kg/cm ² ·G when the reaction temperature reached 150°C, and then gradually decreased to 14 kg/cm ² ·G at the end of the reaction. After cooling the autoclave, the contents were taken out and the excess carbon dioxide charged was released, and the target product was recovered by distillation under reduced pressure, yielding 108 parts of isobutylene carbonate with a purity of 99% or higher. The yield based on the raw material isobutylene oxide was 93.1%. Example 2 72 parts of isobutylene oxide, 1.5 parts of _Cl2Ti (OBu) ₂ (dichlorotitanium dibutoxide), and 3.0 parts of 2-methylpyridine were placed in a stainless steel autoclave.
and sealed. Next, 54 parts of carbon dioxide was introduced under pressure, and the mixture was gradually heated with stirring and allowed to react at 150°C for 1.5 hours. Maximum pressure is 52Kg/cm ²・G to 16Kg/
It became cm ²・G. Perform the same process as in Example 1,
Isobutylene carbonate 107.6 with purity over 99%
I got the department. The yield based on the raw material isobutylene oxide was 92.8%. Comparative Example 1 72 parts of isobutylene oxide, 1.2 parts of anhydrous aluminum chloride consisting of a known catalyst system disclosed in Japanese Patent Publication No. 48-27314, and 2.7 parts of pyridine were placed in a stainless steel autoclave, and the autoclave was sealed. Next, 54 parts of carbon dioxide was introduced under pressure, and the mixture was heated slowly while stirring to react at 150°C for 2 hours. pressure is maximum
It went from 54Kg/cm ²・G to 20Kg/cm ²・G. The same treatment as in Example 1 was carried out, but there were more by-products than in Example 1, and only 83.6 parts of less than 99% (98%) isobutylene carbonate were obtained. Yield based on raw material isobutylene carbonate is 72.1
It was %. Comparative Example 2 The same reaction as in Comparative Example 1 was carried out except that 1.5 parts of aluminum triethoxide and 3.0 parts of pyridine were used as catalysts, but no isobutylene carbonate was obtained. Examples 3 to 6 Reactions were carried out in the same manner as in Example 1 using various epoxy compounds, carbon dioxide, and various catalyst systems in the same autoclave as used in Example 1. The reaction conditions and results are shown in Table 1. 【table】

Claims (1)

[Claims] 1. At least one compound selected from the following compound group (1):
An organic carbonate produced by reacting carbon dioxide with an epoxy compound represented by the general formula (3) below in the presence of a species compound and at least one compound selected from the compound group (2) below. Production method. (1) A group of alkoxide compounds of iron, aluminum, zinc, titanium, tin or antimony that are bonded to at least one halogen atom. (2) A group of compounds consisting of pyridine, quinoline, isoquinoline, or derivatives thereof. (3) General formula Here R ₁ represents a hydrogen atom or a methyl group,
R ₂ represents a methyl group, an ethyl group or a phenyl group.