JPH0625105A - Production of carbonic acid ester - Google Patents

Abstract

PURPOSE:To produce a carbonic acid ester from an alcohol, carbon monoxide and oxygen in high yield and selectivity. CONSTITUTION:An alcohol is reacted with carbon monoxide and oxygen in the presence of a copper catalyst such as a cuprous halide under about 1-100 atom at about 80-200 deg.C. When a halide of a metal with the orbit d of groups 4 to 7 of the periodic table is added to the reactional system, a copper catalyst will not precipitate so that a high catalytic activity is shown with a small amount. Chloride of titanium, tin, niobium, bismuth, molybdenum or manganese is used as the halide of the metal.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a carbonic acid ester by reacting alcohols with carbon monoxide and oxygen in the presence of a copper catalyst.

[0002]

BACKGROUND OF THE INVENTION Carbonic acid esters are used as gasoline additives, organic solvents, and in the production of fine chemicals such as various carbonates, carbamates, urethanes, pharmaceuticals and agricultural chemicals. It is a compound that is useful as a substitute for phosgene.

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 have been proposed for producing a carbonate ester by a liquid phase method or a gas phase method without using such phosgene.

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. It may be precipitated as copper oxalate by the reaction with oxalic acid. Therefore, it is difficult to continuously produce the carbonate ester without deactivating the catalyst. In particular, the oxalate salt is produced via the platinum group metal complex as is the intermediate when carbonic acid ester is produced. Therefore, the formation of oxalate 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. Further, cuprous halide such as cuprous chloride is generally difficult to dissolve in an organic solvent, so that the slurry concentration of the reaction mixture becomes higher and the workability is likely to deteriorate.

Further, in the method using the cupric halide as a catalyst, although the solubility in an organic solvent is high, the number of halogen atoms bonded to copper is larger than that of cuprous halide, so that the reaction The amount of halogen liberated in the system 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 liberated. Therefore, as compared with the cuprous halide-based catalyst, the device material is more likely to be corroded. further,
The liberated halogen reacts with the alcohol and reaction products in the system to form a halide, which is discharged from the reaction system, making the catalyst unstable and reducing the activity or dissolving it during cyclic use. Property is lowered, and continuous reaction tends to be difficult.

Therefore, an object of the present invention is to provide a method for producing a carbonic acid ester which does not deposit a catalyst, exhibits a high catalytic activity, has a high yield and selectivity, does not corrode the equipment, and can be stably produced for a long period of time. To provide.

[0010]

In order to achieve the above-mentioned object, the present inventor has
As a result of extensive studies, a metal having a d orbital of Group 4, 5, 6, or 7 of the periodic table when a carbonate ester is produced by reacting alcohols with carbon monoxide and oxygen in the presence of a copper catalyst. When the halide of is added, the copper catalyst does not precipitate,
The present invention has been completed based on the finding that it exhibits a high catalytic activity and, therefore, a carbonic acid ester can be produced with a high yield and a high selectivity even with a low concentration of a copper catalyst.

That is, the present invention is a method for producing a carbonic acid ester by reacting an alcohol with carbon monoxide and oxygen in the presence of a copper catalyst.
Provided is a method for producing a carbonic acid ester in which a halide of a metal having a d-orbital of Group 7 or Group 7 is added and reacted.

In the present invention, alcohols include
A wide range of compounds having a hydroxyl group can be used, for example methanol, ethanol, 1-propanol, 2
-Propanol, 1-butanol, 1-pentanol,
1-hexanol, 1-octanol, 1-decanol, 1-octadecanol, allyl alcohol, 2-buten-1-ol, 2-hexen-1-ol, etc., saturated or unsaturated aliphatic having 1 to 20 carbon atoms. Alcohol; cyclohexanol, cyclopentanol, etc. with 3 to 3 carbon atoms
Examples of the alicyclic alcohol 7 include 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, and phenolic compounds such as cresol are included in the alcohols. 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 copper catalyst is not particularly limited as long as it is a copper compound used as an oxidative carbonylation catalyst, and examples thereof include strong or weak acids such as copper halides, nitrates, acetates, pivalates and carbonates. And the like.

Of these copper compounds, cuprous compounds,
For example, cuprous halide, cuprous nitrate, cuprous acetate and the like are preferable. Particularly preferred copper compounds include cuprous chloride,
It contains cuprous halides such as cuprous bromide and cuprous iodide, and among them, cuprous chloride is frequently used.

These cuprous compounds have low solubility as described above, but when a specific metal halide is added, the solubility becomes high and high catalytic activity is exhibited. Therefore, the carbonate ester can be produced in high yield with a small amount of copper catalyst.

The concentration of the copper catalyst in the reaction mixture can be appropriately selected in consideration of the reaction rate, operability of post-treatment, economy, etc., but is usually 1 to 3000 mmol / liter, preferably 10 to 1000 mmol. / Liter.

The main feature of the present invention is that a halide of a metal having a d-orbital of Group 4, 5, 6, or 7 of the periodic table is added to the reaction system.

The solubility of the copper compound in the raw material alcohol or the organic solvent is improved by adding a halide of the above-mentioned metal, probably due to the formation of a complex salt with the copper compound which is the catalyst. The target ester carbonate can be obtained in high yield. In particular, when the above-mentioned cuprous compound, particularly cuprous halide such as cuprous chloride, is used as a copper catalyst, the effect is remarkable.

When the copper catalyst is a copper halide, in general, halogen is likely to be liberated in the reaction process. When the metal halide is added to the reaction system,
Since this compound has a d orbital, a free halogen can be coordinated. Therefore, it is possible to stabilize the catalyst and prevent corrosion of the device due to halogen.

D of Group 4, Group 5, Group 6 or Group 7 of the periodic table
Metals having orbits include titanium, zirconium, hafnium, tin, and lead group 4 metals; vanadium, niobium, tantalum, antimony, and bismuth group 5 metals; chromium,
Metals of Group 6 of molybdenum and tungsten; metals of Group 7 of manganese, technetium and rhenium are included.

Of these, metals such as titanium, tin, niobium, bismuth, molybdenum and manganese are preferably used.

The above-mentioned halides include the above-mentioned metal fluorides, chlorides, bromides and iodides. Of these, chloride is especially frequently used.

As a metal halide having a d-orbital group 4, 5, 6 or 7 of the periodic table, for example, titanium dichloride, titanium trichloride, titanium tetrachloride, titanium dibromide, titanium tribromide. , Titanium tetrabromide, zirconium dichloride, zirconium tetrachloride, hafnium tetrachloride, tin dichloride, tin tetrachloride, tin dibromide, tin tetrabromide, lead dichloride, lead tetrachloride, vanadium dichloride, trichloride Vanadium, vanadium tetrachloride, niobium trichloride, niobium pentachloride, niobium tribromide,
Niobium pentabromide, tantalum dichloride, tantalum trichloride, tantalum tetrachloride, tantalum pentachloride, antimony trichloride, antimony pentachloride, bismuth trichloride, bismuth tribromide, chromium trichloride, molybdenum dichloride, molybdenum trichloride, Molybdenum tetrachloride, molybdenum pentachloride, molybdenum dibromide,
Molybdenum tribromide, molybdenum tetrabromide, tungsten dichloride, tungsten tetrachloride, tungsten pentachloride, tungsten hexachloride, manganese dichloride, manganese trichloride, manganese tetrachloride, manganese dibromide, rhenium trichloride, rhenium tetrachloride , Rhenium pentachloride, rhenium hexachloride and the like.

Of these, titanium trichloride, titanium tetrachloride, tin dichloride, tin tetrachloride, niobium pentachloride, bismuth trichloride, molybdenum pentachloride, manganese dichloride, etc. are particularly preferably used.

The metal halides may be used alone or in combination of two or more.

The amount of the metal halide used is usually 0.01 to 1 mol with respect to 1 mol of the copper compound used as the catalyst.
The amount is 20 mol, preferably 0.05 to 15 mol, and more preferably 0.1 to 10 mol. If it is less than 0.01 mol, the effect of addition is small, and if it exceeds 20 mol, it is difficult to obtain a larger effect commensurate with the amount added.

The reaction of alcohols with carbon monoxide and oxygen may be carried out in the absence of a solvent, or may be carried out in a solvent inert to the reaction. Examples of the solvent include ketones such as acetone, methyl ethyl ketone, and cyclohexanone; diethyl ether, dibutyl ether,
Ethers such as dimethoxyethane, dioxane and tetrahydrofuran; carboxylic acids such as formic acid, acetic acid and propionic acid; carboxylic acid esters such as methyl acetate, ethyl acetate, isopropyl acetate, butyl acetate, amyl acetate, cellosolve and ethyl propionate; N, Carboxylic acid amides such as N-dimethylformamide; acetonitrile,
Nitriles such as propionitrile and benzonitrile; Aliphatic hydrocarbons such as hexane and octane; Alicyclic hydrocarbons such as cyclohexane; Aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene; Carbon tetrachloride, chloroform, dichloromethane , 1,2-dichloroethane, and other halogenated hydrocarbons; carbonic acid esters, which are target compounds, and the like. These solvents may be used alone or in combination of two or more.

The reaction components carbon monoxide and oxygen may be diluted with a gas inert to the reaction, such as nitrogen, argon, helium, carbon dioxide or the like.

Ratio of carbon monoxide to oxygen (CO / O ₂ ).
Is usually about 1/1 to 100/1 (molar ratio).

The reaction temperature is usually 80 to 200 ° C, preferably about 100 to 150 ° C. If it is less than 80 ° C, the reaction rate is slow, and if it exceeds 200 ° C, the vapor pressure is high and the reaction operability is likely to be deteriorated.

The reaction pressure is usually 1 to 100 atm, preferably about 5 to 50 atm.

The reaction can be carried out continuously or batchwise.

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

[0035]

EFFECTS OF THE INVENTION According to the method of the present invention, the precipitation of copper catalyst is significantly suppressed and the catalytic activity is high. Esters can be produced.

[0036]

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 A glass-lined autoclave equipped with a stirrer and having an internal volume of 300 ml was charged with 50 ml of methanol containing 200 mmol / liter of cuprous chloride and 200 mmol / liter of titanium tetrachloride, and the gas phase portion was monooxidized. Substituted with carbon. Next, carbon monoxide is added to 23 Kg / cm ² ,
After pressurizing oxygen at 2.0 Kg / cm ² , the reaction temperature was 13
The reaction was carried out at 5 ° C for 45 minutes. Then cool to room temperature,
The reaction product gas and the reaction product solution were analyzed by gas chromatography.

As a result, dimethyl carbonate 63.4
Mmol of carbon dioxide was produced, and 5.2 mmol of carbon dioxide gas was produced as a by-product. After the reaction was completed, cuprous chloride was completely dissolved in the reaction mixture.

Comparative Example 1 The same operation as in Example 1 was carried out except that 50 ml of methanol containing 600 mmol / liter of cuprous chloride was used in place of methanol containing cuprous chloride and titanium tetrachloride. It was

As a result, dimethyl carbonate 42.9
Mmol was produced and 2.4 mmol of carbon dioxide gas was by-produced. After the completion of the reaction, cuprous chloride was deposited and the reaction mixture was in the form of slurry.

Comparative Example 2 In place of methanol containing cuprous chloride and titanium tetrachloride, 50 ml of methanol containing 200 mmol / liter of cuprous chloride and 200 mmol / liter of lithium chloride was used. The same operation as in 1 was performed.

As a result, dimethyl carbonate 48.7
Mmol was produced, and 3.5 mmol of carbon dioxide gas was by-produced.

After the completion of the reaction, cuprous chloride was precipitated and the reaction mixture was in the form of slurry.

Comparative Example 3 In place of methanol containing cuprous chloride and titanium tetrachloride, 50 ml of methanol containing 200 mmol / liter of cuprous chloride and 200 mmol / liter of magnesium chloride was used. The same operation as in 1 was performed.

As a result, dimethyl carbonate 46.2
Mmol was produced, and 2.8 mmol of carbon dioxide gas was by-produced.

After the completion of the reaction, cuprous chloride was deposited and the reaction mixture was in the form of slurry.

Example 2 In place of the methanol containing cuprous chloride and titanium tetrachloride, 50 ml of methanol containing 200 mmol / liter of cuprous chloride and 200 mmol / liter of stannous chloride was used. The same operation as in Example 1 was performed.

As a result, dimethyl carbonate 65.0
Mmol was produced, and 8.7 mmol of carbon dioxide gas was by-produced.

After the completion of the reaction, cuprous chloride was completely dissolved in the reaction mixture.

Example 3 Example 1 was repeated except that 50 ml of methanol containing 200 mmol / liter of cuprous chloride and 200 mmol / liter of manganese dichloride was used in place of methanol containing cuprous chloride and titanium tetrachloride. The same operation as in Example 1 was performed.

As a result, dimethyl carbonate 76.0
Mmol was produced and 1.3 mmol of carbon dioxide gas was produced as a by-product. After the reaction was completed, cuprous chloride was completely dissolved in the reaction mixture.

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Claims (5)

[Claims] 1. A method for producing a carbonic acid ester by reacting an alcohol with carbon monoxide and oxygen in the presence of a copper catalyst, comprising a d orbital of Group 4, 5, 6, or 7 of the periodic table. A method for producing a carbonic acid ester, which comprises reacting a metal halide having: 2. The metal having a d orbital is titanium, tin,
The method for producing a carbonic acid ester according to claim 1, which is niobium, bismuth, molybdenum or manganese. 3. The method for producing a carbonic acid ester according to claim 1, wherein the copper catalyst is a cuprous compound. 4. The method for producing a carbonate ester according to claim 1, wherein the copper catalyst is cuprous halide. 5. The method for producing a carbonic acid ester according to claim 1, wherein the copper catalyst is cuprous chloride.