JPH06192182A - Method for controlling reaction - Google Patents

Abstract

PURPOSE:To control reaction temperature by simple equipment and simple operations. CONSTITUTION:In an exothermic reaction which is conducted in a liquid phase between a liquid reactive component and a vapor reactive component, a gas of the vapor phase in a reaction vessel 1 is put to gas/liquid separation using e.g. a condenser, and the non-condensable gas separated is circulatorily fed to the liquid phase in the reaction vessel. The liquid component in the liquid phase is then evaporated; at this time, heat is taken from the liquid phase owing to the latent heat of vaporization. Therefore, reaction temperature can easily be controlled by regulating the circulatory flow of the non-condensable gas by a flow control valve 15. This method for controlling reaction temperature can suitably be used in e.g. a process for producing a carbonic ester from an alcohol, carbon monoxide and oxygen.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the reaction temperature of an exothermic liquid phase reaction. The present invention also relates to a method for producing a carbonic acid ester by reacting alcohol, carbon monoxide and oxygen in a liquid phase to obtain a carbonic acid ester.

[0002]

2. Description of the Related Art In a liquid phase reaction using a gas as a reaction component, it is known that heat is often generated. As a method of controlling the reaction temperature of the liquid phase reaction accompanied by such heat generation, a cooling medium is circulated through a jacket provided outside the reactor or a coil provided inside the reactor, and the medium is cooled. Generally, a method of controlling the temperature or flow rate is used. However, in this method, it may be difficult to control the reaction temperature when a sudden temperature change occurs, and moreover,
Low heat removal efficiency. Especially when the volume of the reactor is large, it is difficult to control the reaction temperature efficiently.

Examples of the liquid phase reaction involving the generation of heat using a gas as the reaction component include, for example, Wacker reaction, oxo reaction, reaction for obtaining carboxylic acid or carboxylic acid anhydride from alcohol and / or its ester and carbon monoxide, alcohol. It is known that a carbonic acid ester is obtained from carbon monoxide and oxygen.

For example, a method of producing a carbonic acid ester by reacting the alcohol, carbon monoxide and oxygen in a liquid phase is roughly classified into a method using a copper compound as a main catalyst and a method using a palladium compound as a main catalyst. There are two ways.

A method of using a copper compound as a main catalyst is disclosed in JP-B-45-11129 and JP-B-60-5873.
No. 9 publication. In this method, since the catalytic activity of the copper compound is relatively low, it is necessary to use the catalyst at a high concentration of several mol / L (several tens% in terms of weight%) in order to obtain a practical reaction rate. For this reason, oxidizing divalent copper ions and chlorine ions, which are catalytically active species, are present in high concentrations, and the reactor, other devices in contact with the reaction solution, pipes, valves, etc., are significantly corroded.

The method using a palladium compound as the main catalyst is
Japanese Patent Publication No. 61-8816, Japanese Patent Publication No. 61-43338
It is disclosed in Japanese Patent Application Laid-Open No. 1-287062. In this method, a weak acid salt or halide of copper and a weak acid salt or halide of an alkali metal or alkaline earth metal are used as a cocatalyst. Since the palladium compound has a higher catalytic activity than the copper compound, the amount of the catalyst is 1/1 compared with the method using the copper compound as the main catalyst.
It is possible to obtain a sufficient reaction rate even with a small amount of about 000, and the amount of divalent copper ions and the like used together for reoxidizing palladium is 1% as compared with the above method.
It can be reduced to about / 10 to 1/100. However, since the catalytically active species of oxidizing divalent palladium and divalent copper ions show high oxidizing activity even at low concentrations, it remains highly corrosive to the reactor. Absent.

Several processes for producing a carbonic acid ester in a liquid phase using such a catalyst have been proposed.

For example, European Patent Publication No. 134.
No. 668 describes condensing the gas in the gas phase of the reactor,
Disclosed is a continuous production method of carbonic acid ester in which a part of condensed carbonic acid ester is recycled to a reactor to keep water and alcohol in a reaction solution at a low concentration, suppress deactivation of a catalyst, and prevent side reactions. Has been done.

Further, in Japanese Patent Laid-Open No. 3-90441,
To prevent corrosion, an excess amount of carbon monoxide and oxygen-containing gas is supplied to the reactor, and the carbonic acid ester formed, water by-produced and unreacted alcohol are azeotropically extracted in a gaseous state from the reactor. , A continuous production method of separating and recovering a carbonate ester from a condensate after gas-liquid separation is disclosed. In addition, in this case, it is described that the non-condensable gas that has been gas-liquid separated may be returned to the reactor.

Further, European Patent Publication No. 460.
No. 732 describes that a carbon monoxide-containing gas is blown into a reaction solution in order to improve the productivity of carbonic acid diester,
In a method for promoting the evaporation of methanol, water and dimethyl carbonate from a reaction mixture and recovering water and dimethyl carbonate from the obtained gaseous mixture, maintaining the concentration of methanol and water in the reaction solution within a certain range. Disclosed is a continuous process for producing dimethyl carbonate. In this case, the non-condensable gas having a high carbon monoxide concentration is recycled into the reactor.

In the conventional process of the above carbonic acid ester, the reaction temperature is controlled by a general control method, that is,
A method in which a cooling medium is circulated through a jacket or a coil provided in the reactor as described above is generally used. Therefore, as described above, the heat removal efficiency may be low, and it may be difficult to control the reaction temperature. Moreover, since a corrosive catalyst is used in this process, it is necessary to use an expensive corrosion-resistant material for the coil or the like through which the refrigerant passes. Furthermore, in order to improve the corrosion resistance inside the reactor, if the inside of the reactor is lined or coated with a corrosion resistant material such as glass or Teflon, if the cooling medium is circulated and cooled, the coating layer may crack or peel off. There is a case to do.

As another method for controlling the reaction temperature in the above process, there is known a method in which the reaction solution is cooled by a heat exchanger and circulated in the reactor, and the temperature or flow rate of the circulating solution is controlled. However, in this method, it is necessary to use an expensive corrosion-resistant material for the circulation line of the reaction solution in order to prevent the corrosion due to the catalyst contained in the reaction solution, in addition to the cost for the additional equipment. Furthermore, when the reaction solution is circulated, the residence time tends to fluctuate, which makes it difficult to stably manufacture the target product.

Although there is a description of returning the non-condensable gas to the reaction system in the conventional carbonic acid ester production process, no consideration is given to controlling the reaction temperature by this.

In the above-mentioned Wacker reaction, oxo reaction, reaction for obtaining carboxylic acid or carboxylic acid anhydride from alcohol and / or its ester and carbon monoxide, the reaction temperature can be controlled in the same manner as for the reaction for obtaining carbonate ester. Method is used. Therefore, the problems associated with the above reaction for obtaining a carbonate ester are problems common to the above reactions.

Therefore, an object of the present invention is to provide a reaction control method capable of easily controlling the reaction temperature in a liquid phase reaction accompanied by heat generation using a gas reaction component and effectively utilizing an unreacted gas reaction component. To do.

Another object of the present invention is to provide a reaction control method capable of efficiently controlling the reaction temperature regardless of the volume.

Still another object of the present reaction is to provide a reaction control method capable of easily controlling the reaction temperature with a simple equipment and operation even in the presence of a highly corrosive catalyst.

Still another object of the present invention is to provide a method for producing a carbonic acid ester in good yield and stably.

[0019]

The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, gas in the gas phase portion of the reactor is easily gas-liquid separated, and the separated non-condensable gas is used as the liquid in the reactor. It was found that the reaction temperature can be easily controlled by circulating the supply to the phase, and the present invention was completed.

That is, according to the present invention, in an exothermic reaction in which a liquid reaction component and a gas reaction component are reacted in a liquid phase, the gas in the gas phase part of the reactor is gas-liquid separated, and the separated non-condensable gas is used in the reactor. A reaction control method for controlling the reaction temperature is provided by circulating the supply to the liquid phase.

The present invention also provides a method for producing a carbonic acid ester by reacting alcohol, carbon monoxide and oxygen in a liquid phase, wherein the gas in the gas phase of the reactor is gas-liquid separated and the separated non-condensable Provided is a method for producing a carbonic acid ester in which a reaction temperature is controlled by circulatingly supplying a gas to a liquid phase of a reactor.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings as needed.

In the reaction control method of the present invention, the reaction is
There is no particular limitation as long as it is an exothermic reaction for reacting the liquid reaction component and the gas reaction component in the liquid phase. The gas reaction component is
Any reaction component that can be separated as a gas in gas-liquid separation may be used.

In the above reaction, a reaction using a gas such as oxygen, carbon monoxide, hydrogen or the like as a reaction component, for example, a reaction such as a Wacker reaction to obtain a carbonyl compound by oxidizing an olefin; from an olefin, carbon monoxide and hydrogen Oxo reaction for obtaining aldehyde; Reaction for obtaining carboxylic acid or carboxylic anhydride from alcohol and / or its ester and carbon monoxide (for example, reaction for obtaining acetic acid from methanol and carbon monoxide); Alcohol, dialkyl ether, alkyl Reaction of obtaining carboxylic acid and carboxylic anhydride from at least two components of ester and carbon monoxide (for example, reaction of obtaining acetic acid and acetic anhydride from methanol, methyl acetate, and carbon monoxide); alcohol and carbon monoxide Of carbonic acid ester from ethylene and oxygen; ethylene, acetic acid and oxygen It includes a method of obtaining a vinyl acetate in the liquid phase. Among these reactions, a reaction using carbon monoxide and / or oxygen as a gas reaction component, which is highly exothermic, is preferable. In particular, a reaction using carbon monoxide and oxygen as a gas reaction component, for example, a carbonic acid ester forming reaction with alcohol, carbon monoxide and oxygen, is preferably used.

In the reaction for obtaining the carbonyl compound by the oxidation of the olefin, oxygen-containing gas such as oxygen or air is used as a gas reaction component. The reaction is usually carried out by charging an olefin and an oxygen-containing gas into an aqueous hydrochloric acid solution containing a catalyst component containing palladium chloride and optionally copper chloride and the like. Reaction temperature is 50-15
The reaction pressure is about 0 ° C. and about 1 to 10 atm. By this reaction, for example, acetaldehyde can be produced from ethylene and oxygen.

In the oxo reaction, carbon monoxide and hydrogen are used as gas reaction components. The reaction is 1 to 300
It is carried out at a pressure of about atmospheric pressure and a temperature of about 10 to 200 ° C. The reaction can also be carried out in an inert solvent such as toluene. As a catalyst, a cobalt catalyst ([HCo (C
O) _4], etc.), nickel catalysts ([Ni (CO) _4], etc.), iron catalysts _{([H 2 Fe (CO)} 4] , etc.), rhodium catalysts ([RhH (CO) (PPh 3) 3] , etc. ) Etc. are used. By this reaction, for example, butyraldehyde and / or butanol can be produced from propylene, carbon monoxide and hydrogen.

In the reaction for obtaining a carboxylic acid or carboxylic acid anhydride from the alcohol and / or its ester and carbon monoxide, carbon monoxide is used as a gas reaction component. In this reaction, a rhodium catalyst, a cobalt catalyst, especially a rhodium catalyst is used as a catalyst. In the method for obtaining a carboxylic acid using a rhodium catalyst, usually, an alcohol (for example, methanol) and carbon monoxide are mixed with a rhodium catalyst, an alkyl iodide (for example, methyl iodide),
The reaction is carried out in a reaction solution containing water and an alkali metal halide (eg, lithium iodide). In a preferred method, the reaction is carried out in a liquid phase containing a carboxylic acid (for example, acetic acid) and / or a carboxylic acid ester (for example, methyl acetate) which is a target compound, particularly a carboxylic acid ester. The reaction pressure is usually 1 to 300 atm, preferably about 5 to 150 atm, and the reaction temperature is usually 50 to 300 ° C, preferably 150 to 250 ° C. In a preferred embodiment of this method, the iodide ion concentration in the reaction solution is 0.3 mol / mol.
L or more, preferably about 0.5 to 5 mol / L, and the concentration of water is 10% by weight or less, preferably about 1 to 10% by weight. Incidentally, in this method, JP-A-60-5433 is used.
Reference can be made to the reaction conditions described in JP-A-4. By the above reaction, for example, acetic acid can be efficiently produced from methanol and carbon monoxide.

In the reaction for obtaining a carboxylic acid and a carboxylic anhydride from at least two components of the alcohol, dialkyl ether and alkyl ester and carbon monoxide,
Carbon monoxide is used as the gas reaction component. Further, as the catalyst, rhodium, palladium, cobalt, nickel catalyst, especially rhodium catalyst, etc. are used. The reaction pressure is usually 1 to 300 atm, and the reaction temperature is usually 50 to
It is about 300 ° C. By this reaction, for example, acetic acid and acetic anhydride can be obtained from methanol, methyl acetate and carbon monoxide.

Further, in the reaction for obtaining the carbonate ester from the alcohol, carbon monoxide and oxygen, carbon monoxide and oxygen are used as gas reaction components. In this reaction, palladium halide, copper halide, etc. are used as the catalyst component.

As described above, the catalyst used in the liquid phase reaction is strongly acidic or oxidative and often exhibits strong corrosiveness with respect to metal materials.

In the above reaction, the gas used as a reaction component does not have to be a high-purity gas and may be diluted with a gas inert to the reaction, for example, nitrogen, helium, argon, carbon dioxide or the like. In the reaction using oxygen as a raw material, the raw material gas is preferably diluted with an inert gas in order to prevent the formation of an explosive mixture. In that case,
It is also possible to use air instead of oxygen and use nitrogen in the air as an inert gas. Further, a gas produced as a by-product of the reaction, such as carbon dioxide, may be used as an inert gas for dilution.

The reaction system may be a continuous reaction system, a semi-batch reaction system, or a batch reaction system. Further, the reactor type can be either a stirring tank type or a bubble tank type.

As a typical example of the exothermic reaction in which the liquid reaction component and the gas reaction component are reacted in the liquid phase, a carbonic acid ester formation reaction by alcohol, carbon monoxide and oxygen will be described in detail below.

The alcohol includes compounds having one or more hydroxyl groups in the molecule, such as methanol,
Ethanol, 1-propanol, 2-propanol, 1
-Saturated aliphatic alcohols such as butanol; unsaturated aliphatic alcohols such as allyl alcohol; alicyclic alcohols such as cyclohexanol; aromatic alcohols such as benzyl alcohol and phenol; polyhydric alcohols such as ethylene glycol and polyethylene glycol; included. The aromatic alcohol is used to include phenols having a phenolic hydroxyl group. A preferable alcohol is a monovalent saturated or unsaturated alcohol, for example, an alcohol having about 1 to 6 carbon atoms. Particularly preferable alcohols include methanol and ethanol, and among them, methanol is frequently used.

The reaction may be carried out in a solvent inert to the reaction, and examples of the solvent include ketones such as acetone; ethers such as diethyl ether, dimethoxyethane and tetrahydrofuran; carboxylic acids such as formic acid, acetic acid and propionic acid. Acids; esters such as methyl acetate; N, N-
Amides such as dimethylformamide; nitriles such as acetonitrile; aliphatic hydrocarbons such as hexane and octane; alicyclic hydrocarbons such as cyclohexane; benzene,
Aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as dichloromethane and 1,2-dichloroethane. Further, alcohol which is a reaction raw material or carbonic acid ester which is a target compound may be used as a reaction solvent. These solvents may be used alone or in combination of two or more.

The type of catalyst used in the reaction is not particularly limited, and for example, a copper-based catalyst having a copper compound as a main catalyst, a platinum-group metal catalyst having a platinum-group metal compound such as a palladium compound as a main catalyst, and the like are used. You can

When a copper-based catalyst is used, preferred copper compounds include halides such as chlorides and bromides of monovalent or divalent copper; alkoxy halides such as methoxy chloride; sulfates, nitrates, carbonates and the like. Inorganic acid salts; organic acid salts such as acetate and pivalate; oxides; hydroxides and the like. These can be used alone or in combination of two or more. The amount of the copper compound used as a catalyst is usually 0.0
It is about 1 to 20 mol / L, preferably about 0.1 to 10 mol / L.

As the co-catalyst in the copper-based catalyst, tertiary amine, amidine, alkali metal alcoholate, alkylphosphine, pyridine, imidazole, phosphoric acid amide, cyclic urea and the like are preferably used. In addition, cyclic urea can also be used as a solvent.

As the platinum group metal-based catalyst, particularly, a palladium-based catalyst in which a palladium compound is used as a main catalyst and a weak acid salt or halide of copper and a weak acid salt or halide of an alkali metal or an alkaline earth metal are used together as a cocatalyst. A catalyst is preferably used.

Examples of the palladium compound include halides such as fluorides, chlorides and bromides of palladium; acetic acid, propionic acid, trifluoroacetic acid, formic acid, citric acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid. Examples thereof include salts of organic acids; salts of inorganic acids such as sulfuric acid and nitric acid. Preferred palladium compounds are palladium halides, especially chlorides. The amount of the palladium compound used as the main catalyst is, for example, 0.0001 to 0.1 mol / L, preferably 0.001.
It is about 0.01 mol / L.

Examples of the weak acid salt of copper include salts of organic acids such as acetic acid, propionic acid, pivalic acid, formic acid, lactic acid, citric acid and benzoic acid; salts of inorganic acids such as boric acid and carbonic acid; phenol and cresol. Examples include salts of phenols. The copper halide includes, for example, cuprous chloride, cupric chloride, cuprous bromide, cupric bromide and the like. Of these copper compounds, organic acid salts such as divalent copper acetate, chlorides, etc. are frequently used. These copper compounds may be used alone or in combination of two or more.

The amount of the weak acid salt or halide of copper used is
A wide range can be selected, for example 0.0001 to 10 mol /
L, preferably about 0.001 to 1 mol / L.

The alkali metal includes lithium, sodium, potassium, rubidium, cesium and the like.
Moreover, beryllium, magnesium, calcium, barium, etc. are contained in an alkaline earth metal.

Examples of weak acid salts of alkali metals or alkaline earth metals include salts of the above organic acids, inorganic acids and phenols. In addition, halides of alkali metals or alkaline earth metals include fluorides, chlorides, bromides and the like. Of these alkali metal or alkaline earth metal compounds, organic acid salts such as acetate and chlorides are often used. The alkali metal or alkaline earth metal compounds can be used alone or in combination of two or more.

The alkali metal or alkaline earth metal compound has the effect of suppressing the conversion reaction of carbon monoxide into carbon dioxide and increasing the selectivity of carbonate ester. The amount of the alkali metal or alkaline earth metal compound used is, for example, about 0.1 to 1000 times mol, preferably about 10 to 200 times mol, of the copper compound.

In the above palladium-based catalyst,
At least one component of the palladium compound, the copper compound and the alkali metal or alkaline earth metal compound,
It preferably contains a halogen atom.

When both the copper atom and the halogen atom are contained in the catalyst component, the atomic ratio of halogen to copper (halogen / copper ratio) is preferably 0.5 to 2, particularly preferably 1.5 to 1. It is about 0.8. The halogen / copper ratio has a great influence on the reaction rate. When it is less than 0.5, the solubility of copper is lowered, and when it exceeds 2, the reaction rate is remarkably reduced.

The reaction pressure can be selected within the range where the reaction efficiency is not impaired and the production of by-products can be suppressed. For example, 5 to 50 Kg.
/ Cm ² , preferably about 15 to 40 Kg / cm ² .

The carbon monoxide partial pressure can be selected within a range that does not reduce the reaction rate. For example, 0.5~47Kg / cm ² about the case of using a copper-based catalyst, is preferably about 0.5 to 5 kg / cm ² in the case of using a palladium catalyst.

The oxygen partial pressure is not particularly limited, but is usually
It is selected in the range that does not form an explosive mixture, eg 0.0
5-10 Kg / cm ² , preferably 0.05-5 Kg /
It is about cm ² .

The reaction temperature can be selected within a range in which the reaction rate is not lowered and the by-production of oxalate ester is suppressed, and is, for example, 50 to 200 ° C., preferably 100 to 150 ° C. If the reaction temperature is too low, the reaction rate is low and the by-product rate of oxalate ester and the like is high. If the reaction temperature is too high, the vapor pressure of the reaction liquid increases and the overall pressure rises, which necessitates the use of a reactor having high pressure resistance, which is not preferable from the viewpoint of equipment cost and economy.

In this way, the corresponding carbonate ester is produced from the alcohol, carbon monoxide and oxygen.

The main feature of the present invention is that the reaction temperature is controlled by gas-liquid separating the gas in the gas phase of the reactor and circulating and supplying the separated non-condensable gas to the liquid phase of the reactor. .

Gas-liquid separation of the gas in the gas phase of the reactor can be carried out by cooling with a heat exchange means such as a condenser. For example, when a carbonic acid ester is produced by the carbonic acid ester production reaction, the temperature at which the alcohol used as a raw material, the carbonic acid ester to be produced, and water as a by-product are condensed under a reaction pressure, for example, from −10 ° C. to
Gas-liquid separation can be performed by cooling to about 50 ° C.

In the method of the present invention, in order to increase the gas-liquid contact efficiency and increase the surface area of bubbles to improve the heat removal efficiency by latent heat of vaporization and the like, the pressure of the non-condensable gas is increased by the compressor and the liquid of the reactor is discharged. It is preferable to sparg on the phase part. By sparging the non-condensable gas into the liquid phase portion of the reactor, the reaction temperature can be efficiently controlled regardless of the volume of the reactor.

When the gas-liquid separated non-condensable gas is supplied to the liquid phase, the reaction liquid is cooled by the gas itself cooled in advance by the gas-liquid separation, and at the same time the liquid component in the liquid phase (for example, In the case of the carbonic acid ester formation reaction, it is cooled by the latent heat of vaporization when the raw material alcohol, the generated carbonic acid ester and the like) are vaporized into the gas which is circulated and supplied. Therefore, the reaction temperature can be controlled by circulating and supplying the non-condensable gas to the liquid phase of the reactor.

The amount of heat generated by the reaction is ΔH ₁ , the amount of heat removed from the reactor or the amount of heat taken out when the reaction solution is taken out is the amount of heat removed even when the non-condensable gas is not circulated, ΔH ₂ , and the non-condensable gas is When the amount of heat removed by circulating supply to the liquid phase is ΔH ₃ , the following equation holds in a steady state where the reaction temperature is constant.

ΔH ₁ = ΔH ₂ + ΔH ₃ On the other hand, ΔH ₃ changes depending on the temperature and the supply amount of the non-condensable gas. Therefore, the reaction temperature can be controlled by adjusting the circulation gas flow rate of the non-condensable gas supplied to the liquid phase or by adjusting the temperature of the non-condensable gas.

The circulation amount of the non-condensable gas separated into gas and liquid can be adjusted by using a flow rate adjusting valve. The opening / closing degree of the valve may be manually operated, but is preferably automatically controlled. According to this automatic control, the reaction temperature can be easily and accurately controlled. In automatic control, the fact that the degree of cooling of the reaction liquid is proportional to the supply amount of the non-condensable gas can be used. The automatic control for adjusting the supply amount of the non-condensable gas to the liquid phase of the reactor can be performed by the feedback control device. This device
Temperature detection means such as a temperature sensor for detecting the reaction temperature in the reactor, the detection value detected by this temperature detection means,
In response to a control amount (deviation) of the non-condensable gas with respect to the reference value based on the reference value set corresponding to the reaction temperature, and a signal related to the control amount by the calculating means, A control means for controlling the opening / closing time and the opening / closing degree of a valve such as an electromagnetic valve for adjusting the supply amount of the condensable gas and a diaphragm valve is provided.

Thus, when the detected value of the reaction temperature exceeds the reference value, the circulation amount of the non-condensable gas circulated in the reactor is increased, and conversely, when the detected value of the reaction temperature is less than the reference value. In some cases, the reaction temperature can be controlled by reducing the circulation rate.

When a compressor is provided in the non-condensable gas circulation line, it is preferable to install bypass pipes before and after the compressor. By providing the pipe, an excessive amount of the gas compressed by the compressor flows into the pipe, so that the gas flow rate can be adjusted extremely smoothly, and therefore the reaction temperature can be controlled easily and accurately. be able to.

The circulating gas flow rate of the non-condensable gas is determined by the type of reaction, the type and amount of the reaction raw materials, the reaction temperature, the amount of the reaction solution withdrawn, the size and shape of the reaction apparatus, the temperature of the non-condensable gas, the condensate. Although it cannot be generally stated because it changes depending on the presence or absence of recycling to the reactor, for example, in the case of producing a carbonic acid ester by the carbonic acid ester forming reaction, for example, 0.5 to 5 Nm per 1 L of the volume of the reaction liquid. ³ / H, preferably about 0.8 to ³ Nm ³ / H.

The temperature of the non-condensable gas can be adjusted by providing a heat exchanger in the non-condensable gas circulation line and adjusting the temperature and / or the flow rate of the refrigerant in the heat exchanger. You may adjust the temperature of the refrigerant of the heat exchanger used at the time of gas-liquid separation of the gas in the gas phase of the reactor. The adjustment of the temperature or the flow rate of the refrigerant in the heat exchanger can be performed manually or automatically as in the adjustment of the circulation amount of the non-condensable gas.

Since the cooling effect by the latent heat of vaporization is extremely large, the reaction temperature can be effectively controlled by adjusting the circulating gas flow rate of the non-condensable gas. Further, the adjustment of the circulation gas flow rate of the non-condensable gas and the adjustment of the temperature of the non-condensable gas can be combined. By combining the adjustment of the flow rate and temperature of the non-condensable gas, it is possible to quickly deal with the case where the temperature inside the reactor changes suddenly, and it is possible to adjust the temperature delicately. It can be manufactured extremely stably.

The composition of the gas circulated in the liquid phase varies depending on the reaction conditions such as the type of reaction and the type of catalyst and is not particularly limited, but it is an inert gas that does not participate in the reaction from the viewpoint of easy control of the reaction temperature. The gas concentration is, for example, 25% by volume or more,
Above all, it is preferably 40% by volume or more, particularly 60% by volume or more (for example, about 70 to 99% by volume). For example, in the case of producing a carbonic acid ester by the carbonic acid ester forming reaction, for example, when a palladium-based catalyst is used, the concentrations of the reaction components oxygen and carbon monoxide are less than 40% by volume in total, and the carbon dioxide that does not participate in the reaction is The concentration of the inert gas component such as carbon or nitrogen is preferably 60% by volume or more. Further, in this case, the particularly preferable composition of the circulating gas is 0.1 to 10% by volume of oxygen and 0.1% of carbon monoxide.
~ 20% by volume, inert gas such as carbon dioxide 70-99
It is about% by volume.

The composition of the circulating gas can be analyzed by, for example, a gas chromatograph. In addition, by analyzing this composition, the supply amount of reaction components such as oxygen and carbon monoxide to the reactor can be adjusted.

In the method of the present invention, a buffer tank for the non-condensable gas may be provided in the circulation line for the non-condensable gas, and particularly in the upstream side of the compressor when the compressor is provided. If a buffer tank is provided and the temperature inside the reactor rises rapidly and the circulating gas flow rate needs to be significantly increased, the non-condensable gas in the buffer tank with a large volume is used to disturb the reaction system. Without, the reaction temperature can be controlled quickly and accurately. In addition, unreacted reaction components can be used extremely effectively. The inlet side of the non-condensable gas of the buffer tank may be provided with a check valve for restricting the non-condensable gas from flowing backward from the buffer tank to the gas-liquid separation heat exchanger. Further, the buffer tank may be a cylinder type. When a cylinder type buffer tank is used, the volume changes in response to pressure fluctuations, so the reaction temperature can be controlled while the pressure of the reaction system is kept stable, and the target compound can be produced stably.

Further, in the method of the present invention, the reactor may be provided with an inert gas supply line equipped with a flow rate control valve. If an inert gas supply line is provided, the opening / closing time of the flow rate control valve and the opening / closing time of the flow rate control valve and The reaction temperature can be quickly and accurately controlled by adjusting the degree of opening and closing. The opening / closing time and opening / closing degree of the valve may be manually operated, but are preferably automatically controlled. The automatic control can be performed by the feedback control device as described above.

According to the method of the present invention, the gas in the gas phase portion of the reactor is gas-liquid separated, and the separated non-condensable gas is circulated and supplied to the liquid phase of the reactor, so that it contains a corrosive catalyst component. Unlike the case where the reaction solution is circulated and cooled, there is no need to use an expensive corrosion resistant material, and the reaction temperature can be controlled by a simple device and operation. Further, unlike the case where the refrigerant is flown through the jacket of the reactor, it is possible to prevent the corrosion-resistant coating in the reactor from cracking or peeling.

Further, since the cooled gas is introduced into the liquid phase, the heat removal efficiency is high and the temperature control is easy.

Further, since the non-condensable gas contains reaction components of unreacted gas, not only the reaction components are efficiently used for the reaction but also the control of the reaction temperature is performed. It is effectively used. When an inert gas is by-produced during the reaction, this can be used as a diluting gas.
For example, when a carbonic acid ester is produced by the carbonic acid ester forming reaction, the non-condensable gas contains carbon dioxide by-produced in the reaction, unreacted carbon monoxide and oxygen. Therefore, by introducing the non-condensable gas into the liquid phase portion, carbon dioxide produced as a by-product can be used as a diluting gas, and the yield of carbonic acid ester and the utilization rate of carbon monoxide or oxygen can be improved. Therefore, it is extremely advantageous industrially.

The present invention is suitably applied to a continuous system in which a reaction component containing a catalyst is continuously supplied to a reactor to cause a reaction, and a reaction liquid and a gas are continuously taken out from a reaction system.

The reaction solution is subjected to a conventional separation process such as distillation and solvent extraction to obtain the target compound. For example, in the carbonic acid ester formation reaction, a carbonic acid ester corresponding to the raw material alcohol is produced.

Unreacted reaction components in the reaction liquid extracted from the reaction system can be recycled to the reaction system together with the catalyst.
Also, a condensate containing a liquid reaction component (for example, alcohol), a reaction product (for example, carbonate ester, etc.), etc. obtained by cooling the gas in the gas phase of the reactor and separating the gas and liquid, Can be recycled into the reaction system. By doing so, the yield of the target compound (for example, carbonic acid ester) is improved.

FIG. 1 is a schematic diagram for explaining an example of a continuous reaction, and in this example, a reaction apparatus used in an example described later for producing a carbonic acid ester by the carbonic acid ester forming reaction is shown. There is.

The reactor 1 is equipped with a heating medium jacket 2 for heating to a predetermined temperature at the start of operation, a first supply line 5 for supplying alcohol by a metering pump, and oxygen. A second supply line 4 for supplying, a third supply line 3 for supplying an inert gas, and a fourth supply line 14 for supplying carbon monoxide are connected.

The alcohol containing a catalyst having a predetermined concentration may be continuously supplied to the reactor 1 from the first supply line 5. Further, the second and third supply lines merge into the middle part and extend into the liquid phase in the reactor 1 in order to efficiently perform gas-liquid contact. Further, the flow rates of oxygen, carbon monoxide and the inert gas are controlled by valves, respectively. The reaction gas component and the inert gas are
In order to enhance the gas-liquid contact efficiency, sparging is usually performed in a liquid phase with a sparger at a predetermined composition ratio. By sparging the reaction gas components and the like, the reaction temperature can be efficiently controlled regardless of the volume of the reactor.

The reactor 1 is equipped with a stirrer 21. In this example, a plurality of disk turbine blades are used to efficiently perform the gas-liquid contact reaction.

Further, the reactor 1 is connected to a reaction liquid extraction line 17 communicating with the liquid phase, and a liquid for adjusting the liquid amount of the reaction liquid by continuously extracting the reaction liquid is connected to this line. A surface adjustment valve 18 is attached.

Further, the reactor 1 is connected to a gas extraction line 20 communicating with the gas phase, and a condenser 6 and a pressure adjusting valve 9 are attached to this line. The components condensed by the condenser 6 are circulated to the reactor 1 through a condensate return line 7. In addition, a part or all of the condensed components can be sent to the next step, which is a carbonate ester separation and purification step, through the flow rate control valve 22 and the condensate liquid withdrawal line 23.

The gas component not condensed by the condenser 6 is compressed by the compressor 11 and then reacted with the carbon monoxide through the circulating gas charging line 12 and the fourth supply line 14 where the line 12 joins. It is circulated and supplied to the container 1. The circulating gas flow rate is such that the circulating gas flow rate is a gas flow rate (detected by the flow meter 16) necessary for maintaining a constant reaction temperature detected by the thermometer 19 attached to the reactor. It is controlled by adjusting the opening / closing degree of the adjusting valve 15. This control is based on a thermometer 19 for detecting the reaction temperature in the reactor, the reference value of the non-condensable gas based on a detection value detected by the thermometer and a reference value set corresponding to the reaction temperature. In response to a calculation circuit that calculates the control amount (deviation) with respect to the value, and a signal related to the control amount by this calculation circuit,
This is performed by a feedback control device including a control circuit that controls the opening / closing degree of the flow rate adjusting valve 15 for adjusting the supply amount of the non-condensable gas.

Of the gas compressed by the compressor 11, the remaining part which is not circulated in the reactor is the miniflow flow rate control valve 13 and the circulating gas miniflow line 8.
Through the gas extraction line 20. In addition, a part of the gas component not condensed by the condenser 6 maintains a constant reaction pressure, so that the pressure adjusting valve 9
After that, the gas is discharged to the outside of the reaction system through the offgas line 10.

In the method of the present invention, the line through which the condensate is circulated in the reactor, the circulating gas mini-flow line 8 and the like are not necessarily required lines.

[0084]

According to the control method of the present invention, among the components in the gas phase portion of the reactor, the non-condensable gas is circulated and supplied to the liquid phase portion of the reactor, and the flow rate and / or the temperature of the circulating gas. Since the reaction temperature is controlled by adjusting the temperature, the reaction temperature can be easily controlled by simple equipment and operation even in the presence of a highly corrosive catalyst. Further, since the gaseous reaction components contained in the non-condensable gas are circulated in the reaction system, the utilization rate of the reaction components is improved. Further, since the gas is supplied to the liquid phase portion, the reaction temperature can be efficiently controlled regardless of the volume of the reactor.

Further, according to the production method of the present invention, among the components of the gas phase portion of the reactor, non-condensable gases such as carbon monoxide, oxygen and by-produced carbon dioxide are supplied to the liquid phase portion of the reactor. Since the reaction temperature is controlled by circulating supply and adjusting the flow rate of the circulating gas, the reaction temperature can be easily controlled by simple equipment and operation even in the presence of a highly corrosive catalyst. Can be manufactured stably. Further, the utilization rates of carbon monoxide and oxygen are improved, the yield of carbonic acid ester is increased, and carbon dioxide produced as a by-product can be effectively used.

[0086]

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 pressure-resistant reactor with an internal volume of 200 L equipped with a two-stage disc turbine blade was placed with 0.51 mmol / L of palladium chloride, 50.25 mmol / L of cupric chloride and 6 cupric acetate. A methanol solution in which 0.75 mmol / L, magnesium acetate 57 mmol / L and acetic acid 25.5 mmol / L were dissolved was supplied at a flow rate of 150 L / H, and carbon monoxide was added at 12.9 Nm ³ / H and oxygen was supplied. 6.4N
m ³ / H and nitrogen were supplied at a flow rate of 2.0 Nm ³ / H from a sparger at the bottom of the reactor, and the reaction was carried out at a reaction temperature of 130 ° C.

The liquid level in the reactor was adjusted by continuously withdrawing the reaction liquid from a liquid level control valve provided at the bottom of the reactor so as to maintain the liquid volume at 75 L.

The gas discharged from the reactor was supplied to a two-phase stainless condenser under pressure to remove condensed components such as methanol, dimethyl carbonate and water, and then the non-condensable gas was compressed by a compressor, The reaction temperature is 130
Flow rate required to remove heat to keep the temperature at ℃ 74.0Nm
³ / H was circulated to the reactor. The temperature of the gas passing through the compressor was 36 ° C.

Further, a part of the non-condensable gas was 9.2 Nm ³ / so that the reaction pressure was maintained at 21 kg / cm ² G.
It was discharged from the pressure control valve at a flow rate of H 2.

In order to prevent the formation of an explosive mixture, the oxygen concentration and the carbon monoxide concentration of the gas discharged from the pressure control valve are constantly analyzed by an oxygen concentration analyzer and a gas chromatograph, respectively, and the oxygen and carbon monoxide reactors are analyzed. The amount of gas supplied to the was adjusted. During steady operation, the above-mentioned supply gas amount was constant, the oxygen concentration in the exhaust gas was 4 vol%, the carbon monoxide concentration was 1.4 vol%, and the rest was mainly carbon dioxide and nitrogen.

The methanol, dimethyl carbonate, water and the like condensed by the condenser were returned to the reactor by a natural flow system through a U-shaped liquid seal tube.

15.9% of the methanol fed to the reactor
Changed to dimethyl carbonate.

Under these conditions, the amount of heat generated by the reaction Δ
H ₁ is 40.9 kkcal / H, and the amount of heat ΔH _{2 that} is removed even when the non-condensable gas is not circulated, such as the amount of heat released from the reactor or the amount of heat taken out when the reaction liquid is withdrawn, is 20.
It is 1 kkcal / H. The difference between the two is 20.8 kkcal
As described above, the heat amount of / H is removed by circulatingly supplying the non-condensable gas at a flow rate of 74.0 Nm ³ / H to the liquid phase portion of the reactor, and the reaction temperature is kept constant.

Example 2 Methanol, dimethyl carbonate, water and the like condensed in the condenser were withdrawn at a flow rate of 81 L / H without returning to the reactor,
The reaction was carried out in the same manner as in Example 1 except that it was supplied to the next dimethyl carbonate separation and purification step.

The reaction temperature was maintained at 130 ° C. by circulating the non-condensable gas at a flow rate of 85.4 Nm ³ / H to the liquid phase part of the reactor. The amount of heat generated by the reaction ΔH ₁ is 40.
9 kkcal / H, the heat quantity ΔH _{2 that} is removed even when the non-condensable gas is not circulated, such as the amount of heat released from the reactor or the quantity of heat taken out when the reaction liquid is drawn out, is 16.9 kkcal
/ H, the amount of heat removed by circulating gas ΔH ₃ is 24.0 kkca
It was 1 / H. The heat balance keeps the reaction temperature constant.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a reactor used in Examples.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Reactor 3 ... 3rd supply line 4 ... 2nd supply line 5 ... 1st supply line 6 ... Condenser 7 ... Condensate return line 8 ... Circulating gas mini flow line 9 ... Pressure control valve 10 ... Off gas line 11 ... Compressor 12 ... Circulating gas charging line 13 ... Miniflow flow rate adjusting valve 14 ... Fourth supply line 15 ... Circulating gas flow rate adjusting valve 16 ... Flowmeter 17 ... Reactant extraction line 19 ... Thermometer 20 ... Gas extraction line

Claims (6)

[Claims] 1. In an exothermic reaction in which a liquid reaction component and a gas reaction component are reacted in a liquid phase, gas in a gas phase portion of a reactor is gas-liquid separated, and the separated non-condensable gas is converted into a liquid phase of the reactor. A reaction control method in which the reaction temperature is controlled by circulating supply. 2. The reaction control method according to claim 1, wherein the reaction temperature is controlled by adjusting the flow rate of the gas supplied in a circulating manner. 3. Carbon monoxide and / or as gas reaction components
Alternatively, the reaction control method according to claim 1, wherein the reaction temperature of the reaction using oxygen is controlled. 4. A method for producing a carbonic acid ester by reacting alcohol, carbon monoxide and oxygen in a liquid phase, wherein gas in a gas phase part of the reactor is gas-liquid separated, and the separated non-condensable gas is used in the reactor. The method for producing a carbonic acid ester in which the reaction temperature is controlled by circulating the supply to the liquid phase. 5. The method for producing a carbonic acid ester according to claim 4, wherein the reaction temperature is controlled by adjusting the flow rate of the gas to be circulated. 6. The method for producing a carbonic acid ester according to claim 4, wherein an alcohol having 1 to 6 carbon atoms is used as the alcohol.