JPH0625080A - Preparation of solid catalyst and production of carbonic acid ester using the same - Google Patents

Abstract

PURPOSE:To obtain a solid catalyst for production of a carbonic acid ester, having high activity, long catalytic life and high corrosion resistance. CONSTITUTION:Copper (I) halide such as copper (I) chloride or a copper (I) halide and an organic compound capable of coordinating with the copper (I) halide are treated in the presence of carbon monoxide in an organic solvent such as methanol and carried on a support. As the organic compound, a nitrogen-containing heterocyclic compound, an organophosphorus compound, nitrile, etc., is used. As the support, active carbon, etc., is used. The above- mentioned treatment is carried out at ordinary pressure to about 100kg/cm<2> and at a temperature of about 20-200 deg.C. The catalyst component is uniformly carried on the support because the treatment is carried out in the presence of carbon monoxide gas. This catalyst is preferably used for producing a carbonic acid ester such as dimethyl carbonate, etc., by reacting an alcohol with carbon monoxide in the presence of oxygen.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for preparing a solid catalyst for producing a carbonic acid ester, and a method for producing a carbonic acid ester in which an alcohol and carbon monoxide are reacted in the presence of oxygen using the solid catalyst.

[0002]

Carbonic acid ester is used as an additive for gasoline, an organic solvent, and
It is a compound useful as a substitute for phosgene in the production of fine chemicals such as various carbonates, carbamates, urethanes, pharmaceuticals and agricultural chemicals.

As a method for producing a carbonic acid ester, a method of reacting alcohols with phosgene is industrially carried out. However, in this method, not only phosgene having high toxicity is used, but also highly corrosive hydrogen chloride is produced as a by-product in the reaction process. Therefore, some methods for producing carbonate ester without using such phosgene have been proposed.

As a method for producing a carbonic acid ester by the liquid phase method, a method is known in which an alcohol is reacted with carbon monoxide and oxygen in the presence of a platinum group metal-copper catalyst to obtain a carbonic acid ester. For example, Japanese Patent Publication No. 61-8816 discloses a method of reacting alcohols with carbon monoxide and oxygen in the presence of a platinum group metal compound such as a palladium compound, a copper compound such as copper chloride and an alkali metal salt. Is disclosed.

According to this method, even if the catalyst contains a small amount of a platinum group metal such as palladium, it exhibits high activity, so that the partial pressure of carbon monoxide in the reaction system can be lowered. However, in this catalyst system, a copper compound as a co-catalyst is precipitated as copper oxide, or is converted to basic copper chloride or the like by water produced as a by-product when a carbonic acid ester is formed, and is insoluble or by-produced. Since copper oxalate is precipitated by the reaction with oxalic acid, it is difficult to continuously produce a carbonate ester without deactivating the catalyst. In particular, since the formation of oxalate occurs via the same platinum group metal complex as the intermediate when carbonic acid ester is formed, it is an unavoidable problem as long as a platinum group metal such as palladium is used as the main catalyst.

Another method for producing a carbonic acid ester in a liquid phase is to react an alcohol with carbon monoxide and oxygen in the presence of an oxidative carbonylation catalyst such as cuprous halide or cupric halide. The method is known. For example,
Japanese Patent Publication No. 56-8020 discloses a method using a catalyst composed of a cuprous halide such as cuprous chloride and a halide of an alkali metal or an alkaline earth metal.

However, the cuprous halide catalyst is
Since the activity is lower than that of the above palladium-copper catalyst, a large amount of catalyst is required and a high carbon monoxide partial pressure is required. Therefore, there is a large amount of carbon monoxide purge loss accompanying the purge of carbon dioxide produced as a by-product. Become. Also, cuprous halides such as cuprous chloride are generally difficult to dissolve in organic solvents,
The slurry concentration of the reaction mixture becomes even higher, and the workability tends to deteriorate.

Further, in the above-mentioned method using a cupric halide as a catalyst, the solubility in an organic solvent is high, but since the number of halogen atoms bonded is larger than that of cuprous halide, the reaction system has a large number of halogen atoms. The amount of halogen liberated into the atmosphere also increases. Further, in the reaction process, halogen atoms such as chlorine are replaced by alkoxy groups from a divalent state of copper to form a carbonate ester-forming intermediate, so that halogens such as chlorine are always released. Therefore, as compared with the cuprous halide-based catalyst, the device material is more likely to be corroded. Furthermore, the liberated halogen reacts with the alcohol and reaction products in the system to form a halide, which is discharged from the reaction system, which makes the catalyst unstable and reduces the activity during cyclic use. , Solubility is lowered, and continuous reaction tends to be difficult.

On the other hand, by a gas phase reaction using a solid catalyst,
As a method for producing a carbonate ester, a catalyst in which a copper compound and various additives are supported on a carrier has been proposed.

For example, in Japanese Patent Publication No. 63-503460 (WO87 / 07601), alcohol, carbon monoxide and oxygen are reacted in a gas phase in the presence of a solid catalyst carrying a metal halide such as cupric chloride. The method of making is described. In addition, in International Publication WO90 / 15791,
A method of reacting an alcohol with carbon monoxide and oxygen in the presence of a catalyst in which a tertiary organic phosphorus compound and copper halide such as cupric chloride are supported on a porous carrier is disclosed.

However, the catalysts used in these methods have problems such as insufficient activity and poor stability and deactivation in a relatively short time.

[0012] In general, among solid catalysts carrying a copper compound, a catalyst carrying a copper halide has the highest activity. Therefore, cupric halides such as cupric chloride and cuprous halides such as cuprous chloride are often used as supported catalyst components.

Of these, cupric halides such as cupric chloride are easily dissolved in an organic solvent and easily supported on a carrier, but halogens such as chlorine are likely to be liberated during the reaction, and the activity gradually decreases, Since it corrodes equipment materials, it is difficult to be a practical catalyst.

On the other hand, cuprous halide such as cuprous chloride has the same activity as cupric halide and has the advantage that it hardly causes halogen release and has a low corrosiveness. However, it is difficult to dissolve in an organic solvent and cannot be uniformly loaded on a carrier, so that sufficient activity cannot be obtained.

Further, as described above, in the conventional method for producing a carbonic acid ester, the catalyst is unstable, corrosive, or the activity is not sufficient, so that the catalyst is stable for a long time and the yield is high. It is not possible to produce carbonate ester well.

Therefore, an object of the present invention is to provide a method for preparing a solid catalyst for producing a carbonic acid ester which is highly active, has a long catalyst life and is small in corrosiveness by a simple operation.

Another object of the present invention is to provide a method for producing a carbonic acid ester which is stable for a long period of time and can be produced in high yield.

[0018]

In order to achieve the above-mentioned object, the present inventor has
As a result of diligent studies, cuprous halide was dissolved in various organic solvents to form a uniform solution in the presence of carbon monoxide due to the coordination effect of carbon monoxide. When cuprous monochloride is treated in an organic solvent in the presence of carbon monoxide and loaded on a carrier, cuprous halide is uniformly loaded on the carrier, resulting in high activity, long catalyst life, and corrosion resistance. It was found that a small catalyst for producing a carbonic acid ester was obtained, and the present invention was completed.

That is, the present invention provides a method for preparing a solid catalyst for producing a carbonic acid ester, which comprises (1) a cuprous halide or
(2) Cuprous halide and an organic compound capable of coordinating with cuprous halide (hereinafter referred to as “coordinating compound”) are treated in an organic solvent in the presence of carbon monoxide to form a carrier. A method for preparing a supported solid catalyst is provided.

The present invention also provides a method for producing a carbonic acid ester by reacting an alcohol with carbon monoxide in the presence of oxygen, which is a method for producing a carbonic acid ester using the solid catalyst prepared by the above-mentioned preparation method. provide.

In the present specification, the cuprous halide and the coordinating compound are collectively referred to as "catalytically active component".

The cuprous halide includes cuprous fluoride, cuprous chloride, cuprous bromide and cuprous iodide. These can be used alone or in combination of two or more.
Of the above, from the ease of availability, catalytic activity and stability,
Particularly, cuprous chloride is preferably used.

In the present invention, since cuprous halide is used as the catalytically active component, unlike the cupric halide catalyst, halogen is liberated during the reaction to lower the catalytic activity or corrode the apparatus. A solid catalyst that is stable and non-corrosive is obtained.

In the present invention, only the cuprous halide may be used alone, or the cuprous halide and the coordinating compound may be used in combination. When the cuprous halide and the coordinating compound are used in combination, a catalyst having higher catalytic activity can be obtained.

The coordinating compound is not particularly limited as long as it can coordinate with cuprous halide, and examples thereof include methylamine, ethylamine, ethylenediamine,
Amines such as piperidine; amides such as acetamide and N-methylpyrrolidone; pyridine, pyridine-N-oxide, α-picoline, β-picoline, γ-picoline, quinoline, pyrimidine, pyrrole, imidazole, pyrazole, triazole, oxazole, thiazole. , 2,
Nitrogen-containing heterocyclic compounds such as 2 ', 2 "-terpyridyl;
Organophosphorus compounds such as phosphines such as triphenylphosphine and dimethylphenylphosphine, phosphites such as trimethylphosphite and triphenylphosphite, and phosphorous triamides such as hexamethylphosphorus triamide; acetonitrile, benzonitrile, etc. And nitriles; isonitriles such as methyl isocyanide and phenyl isocyanide; thiourea and the like. These compounds can be used alone or in combination of two or more.

Of the above compounds, nitrogen-containing heterocyclic compounds such as pyridine and imidazole, organic phosphorus compounds such as triphenylphosphine, triphenylphosphite and hexamethylphosphorus triamide, and nitriles such as benzonitrile are particularly preferable. Used for.

When cuprous halide and a coordinating compound are used in combination, each component may be used separately in the preparation of the catalyst, or a copper complex previously synthesized from both may be used. Good. The copper complex, cuprous halide,
Examples thereof include complexes with the above amines, amides, nitrogen-containing heterocyclic compounds, organic phosphorus compounds, nitrites, isonitriles, thioureas, and other coordination compounds.

The amount of the coordinating compound used varies depending on the type of the compound, but is usually 0.01 to 1000 mol, preferably 0.1 to 200 mol, per mol of the cuprous halide.
It is about molar.

It should be noted that other components, for example, halides of metals other than copper are supported as long as the properties of the solid catalyst obtained by the preparation method of the present invention such as high activity, non-corrosiveness and high stability are not impaired. You can also do it.

The main feature of the present invention is that the catalytically active component such as cuprous halide is treated in an organic solvent in the presence of carbon monoxide and is supported on a carrier.

Since cuprous halides such as cuprous chloride are generally difficult to dissolve in an organic solvent, it is difficult to obtain a solid catalyst uniformly supported on a carrier. However, when treated in an organic solvent in the presence of carbon monoxide as in the present invention, the cuprous halide is easily dissolved in the organic solvent to form a uniform solution due to the coordination effect of carbon monoxide. For,
The cuprous halide is uniformly supported on the carrier, and as a result, a solid catalyst having high activity, excellent stability, and long catalyst life can be obtained.

Any organic solvent may be used as long as it can dissolve a catalytically active component such as cuprous halide due to the coordination effect of carbon monoxide to form a uniform solution.
Alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 1-hexanol and ethylene glycol; ketones such as acetone, methyl ethyl ketone and cyclohexanone; ethers such as diethyl ether, dibutyl ether, dimethoxyethane, dioxane and tetrahydrofuran. Carboxylic acids such as formic acid, acetic acid and propionic acid; methyl acetate, ethyl acetate, isopropyl acetate, butyl acetate, amyl acetate,
Carboxylic acid esters such as cellosolve acetate and ethyl propionate; Carboxylic acid amides such as N, N-dimethylformamide; Nitriles such as acetonitrile, propionitrile and benzonitrile; Aliphatic hydrocarbons such as hexane and octane; Fats such as cyclohexane Hydrocarbons such as cyclic hydrocarbons, aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene; halogenated hydrocarbons such as carbon tetrachloride, chloroform, dichloromethane and 1,2-dichloroethane. These can be used alone or in combination of two or more.

Of these solvents, alcohols such as methanol and ethanol are frequently used.

As the carrier, those commonly used as carriers for solid catalysts can be used, and examples thereof include activated carbon, carbon black, alumina, silica, silica-alumina, titania, zirconia, magnesia, silicon carbide, diatomaceous earth, pumice stone, aluminium. Random etc. are illustrated. Of these,
In particular, activated carbon, alumina, silica, titania, zirconia, etc. are preferably used. The surface area of the carrier is not particularly limited, but is, for example, about 20 m ² / g or more.

In the present invention, since cuprous halide and the like are supported on the carrier, the catalytically active component is dispersed on the carrier, the effective surface area of the catalyst is increased, and the reaction rate is increased.

The amount of cuprous halide supported varies depending on the type of carrier, but is usually 0.2 as copper with respect to the carrier.
It is about 20% by weight, preferably about 1-10% by weight.

The treatment in an organic solvent such as cuprous halide is not particularly limited as long as it is in an atmosphere in which carbon monoxide is present. Carbon monoxide alone or an inert gas such as nitrogen, argon or helium is used. It can be performed under an atmosphere diluted with a gas. When diluted with an inert gas, the concentration of carbon monoxide in the gas can be appropriately selected within a range capable of exerting a coordination effect with cuprous halide, for example, a concentration range of 0.1 to 100 vol%.

The above treatment is usually carried out at atmospheric pressure to 100 Kg / c.
m ² , preferably under normal pressure to about 10 Kg / cm ² under pressure, for example, 10 to 200 ° C., preferably 50 to 180 ° C.
It is carried out under moderate temperature conditions. The treatment time varies depending on the temperature and the like, but is, for example, 5 minutes to 24 hours, usually about 10 minutes to 5 hours.

The treatment can be carried out by either a batch system or a continuous system, and the order of adding the catalytically active components and the like is not particularly limited.

For example, the carrier may be charged into a reactor together with a catalytically active component such as cuprous halide and an organic solvent and treated in the presence of carbon monoxide. After treating the components and the organic solvent in the presence of carbon monoxide, a carrier may be added and supported.

When the cuprous halide and the coordinating compound are used in combination, one of them may be first loaded on the carrier and then the other component may be loaded. In this case, at least the cuprous halide is supported by treatment in an organic solvent in the presence of carbon monoxide.

After the above-mentioned operations, the cuprous halide or the mixture or complex of the cuprous halide and the coordinating compound is uniformly dispersed on the carrier by filtering or distilling off the solvent. It is possible to obtain a solid catalyst supported on.

The solid catalyst thus prepared is very suitably used as a catalyst for producing a carbonic acid ester by reacting an alcohol with carbon monoxide in the presence of oxygen.

In the method for producing a carbonic acid ester of the present invention, since the solid catalyst having high activity and high stability as described above is used, the carbonic acid ester can be produced stably for a long time in a high yield.

The method for producing a carbonate ester using the above solid catalyst will be described below.

The alcohol used as the reaction raw material is, for example, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-octanol, 1-decanol, 1-octadeca. A saturated or unsaturated aliphatic alcohol having 1 to 20 carbon atoms such as a nor or an allyl alcohol;
Examples thereof include alicyclic alcohols having 3 to 6 carbon atoms such as cyclohexanol and cyclopentanol; aromatic alcohols such as benzyl alcohol and phenethyl alcohol. Further, not only monohydric alcohols but also dihydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, and propylene glycol; polyhydric alcohols such as glycerin, phenolic compounds such as cresol, and the like A compound having a hydroxyl group is also included.

Of these alcohols, aliphatic alcohols having 1 to 4 carbon atoms such as methanol, ethanol, 1-propanol and 1-butanol are preferably used,
Among them, methanol is often used.

The production method of the present invention can be applied to both gas phase reaction and liquid phase reaction.

When the carbonic acid ester is produced by the gas phase reaction, the reaction temperature is usually 60 to 200.
° C., preferably about 100 to 150 ° C., the reaction pressure is usually normal pressure to 50 kg / cm ^2, preferably atmospheric pressure ~30K
g / cm ² , and the space velocity of the supply gas is, for example, 10
0-50000h ^-1 , preferably 500-5000h ^-1
It is a degree.

In the case of producing a carbonic acid ester by liquid phase reaction, the reaction temperature is, for example, about 80 to 150 ° C., and the reaction pressure is about ² to 100 Kg / cm ² .

The amount of carbon monoxide used is not particularly limited, but is usually 0.1 to 1000 mol, preferably 0.2 to 100 mol, and more preferably 0.5 to 1 mol of the alcohol used as a raw material. It is about 20 mol. The amount of oxygen used is usually 0.0 per mol of alcohol.
It is about 1 to 2 mol, preferably about 0.01 to 1.5 mol.

Oxygen can be used as pure molecular oxygen or diluted with a gas inert to the reaction, such as nitrogen, argon or helium.

The production method of the present invention can be carried out continuously or batchwise using a fixed bed or fluidized bed reactor.

By treating the reaction product according to a conventional method, a carbonic acid ester corresponding to the starting alcohol can be obtained.

[0055]

According to the preparation method of the present invention, since the catalyst components such as cuprous halide are uniformly supported on the carrier, the carbonic acid ester having high activity, long catalyst life and small corrosiveness is obtained. A solid catalyst for production is obtained.

Further, according to the production method of the present invention, since the solid catalyst having the above excellent properties is used, the carbonate ester is stably collected for a long period of time by the reaction of alcohol with carbon monoxide and oxygen. It can be manufactured efficiently.

[0057]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited by these examples.

Example 1 50 g of activated carbon having a surface area of 1000 m ² / g and 3.9 g of cuprous chloride were placed in an autoclave having a glass-lined interior, and 100 ml of methanol was further added. After replacing the gas phase in the autoclave with carbon monoxide, 1
It processed at 30 degreeC for 1 hour. After slow cooling, carbon monoxide was released. The obtained mixed liquid was filtered to obtain a solid catalyst in which cuprous chloride was supported on activated carbon.

This solid catalyst was prepared with an inner diameter of 10 mm and a length of 45.
A 0 mm stainless steel reaction tube was filled to a layer length of 10 mm, the reaction temperature was set to 130 ° C., and CO / O was set.
₂ / N ₂ / methanol = 37/3/57/3 (molar ratio)
The mixed gas consisting of 2 h was passed for 2 hours at a space velocity (SV) of 2000 h ⁻¹ . During this period, the pressure in the reaction tube was 5 kg / c.
It was held at m ² . The reaction product gas flowing out from the outlet of the reaction tube was aggregated with a dry ice trap at -70 ° C, and the composition of the obtained aggregated liquid and exhaust gas was analyzed by gas chromatography.

As a result, 9.3 mg of dimethyl carbonate was obtained (yield 4.7%).

Comparative Example 1 Example 1 was repeated except that the carbon monoxide substitution operation was omitted.
The same reaction as in Example 1 was carried out using the solid catalyst prepared in the same manner as in.

As a result, the amount of dimethyl carbonate obtained was 0.4 mg (yield 0.2%). It is considered that the reason why the yield is remarkably lower than that in Example 1 is that cuprous chloride was not uniformly supported on the activated carbon.

Example 2 50 g of activated carbon having a surface area of 1000 m ² / g, 3.9 g of cuprous chloride and 34 g of imidazole were charged into an autoclave having a glass-lined interior, and 100 ml of methanol was further added. After replacing the gas phase in the autoclave with carbon monoxide, the autoclave was treated at 130 ° C. for 1 hour. After slow cooling, carbon monoxide was released. The obtained mixed liquid was filtered to obtain a solid catalyst in which a cuprous chloride-imidazole complex was supported on activated carbon.

Using this catalyst, the same reaction as in Example 1 was carried out. As a result, 15.0 mg of dimethyl carbonate was obtained (yield 7.7%).

Comparative Example 2 Example 2 was repeated except that the carbon monoxide substitution operation was omitted.
The same reaction as in Example 1 was carried out using the solid catalyst prepared in the same manner as in.

As a result, the amount of dimethyl carbonate obtained was 6.3 mg (yield 3.2%). It is considered that the reason why the yield was lower than that in Example 2 was that cuprous chloride and imidazole were not uniformly supported on the activated carbon.

Example 3 3.9 g of cuprous chloride and 34 g of imidazole were placed in a glass-lined autoclave, and 100 ml of methanol was added. After replacing the gas phase in the autoclave with carbon monoxide, the autoclave was treated at 130 ° C. for 1 hour. After slow cooling, carbon monoxide was released.
A homogeneous solution of the cuprous chloride-imidazole complex was obtained. 50 ml of activated carbon having a surface area of 1000 m ² / g was added to this solution.
g, stirred for a while, filtered the mixture,
A solid catalyst in which a cuprous chloride-imidazole complex was supported on activated carbon was obtained.

Using this solid catalyst, the same reaction as in Example 1 was performed. As a result, 10.3 mg of dimethyl carbonate was obtained (yield: 5.2%).

Examples 4 to 8 The same reaction as in Example 1 was carried out using the solid catalyst prepared in the same manner as in Example 2 except that the following coordination compound was used instead of imidazole.

Example 4 Pyridine 80 g Example 5 Triphenylphosphine 79 g Example 6 Triphenylphosphite 98 g Example 7 Benzonitrile 53 g Example 8 Hexamethylphosphorus triamide 49 g The results are shown in Table 1.

[0071]

[Table 1] Examples 9 to 12 The same reaction as in Example 1 was performed using the solid catalyst prepared in the same manner as in Example 1 except that the following carrier was used instead of the activated carbon.

Example 9 Alumina (surface area 150 m ² / g) 120 g Example 10 Silica (surface area 350 m ² / g) 60 g Example 11 Titania (surface area 30 m ² / g) 200 g Example 12 Zirconia (surface area 40 m ² / g) 180 g The results are shown in Table 2.

[0073]

[Table 2]

Claims (3)

[Claims] 1. A method for preparing a solid catalyst for producing a carbonic acid ester, comprising: (1) cuprous halide or (2) cuprous halide and an organic compound capable of coordinating with cuprous halide; A method for preparing a solid catalyst which is treated in an organic solvent in the presence of carbon monoxide and supported on a carrier. 2. The solid catalyst according to claim 1, wherein the organic compound capable of coordinating with cuprous halide is at least one compound selected from the group consisting of nitrogen-containing heterocyclic compounds, organic phosphorus compounds and nitriles. Method of preparation. 3. A method for producing a carbonic acid ester by reacting an alcohol with carbon monoxide in the presence of oxygen, which is a method for producing a carbonic acid ester using the solid catalyst prepared by the preparation method according to claim 1.