JPS6059899B2 - Method for producing benzophenoneazines - Google Patents

Description

Detailed Description of the Invention The present invention oxidizes benzophenone imines (hereinafter abbreviated as imines) with molecular oxygen in the presence of a copper salt catalyst,
Benzophenone Azine (hereinafter abbreviated as Azine)
Continuously (by continuous reaction) manufacturing method.

There are many known methods for oxidizing imines to produce the corresponding azines. A method for producing azines by oxidizing imines in the presence of a cuprous chloride catalyst is known from US Pat. No. 2,870,206.

In this method, there are many cases in which the catalyst is affected by by-product water and copper salts precipitate during the reaction, resulting in a significant decrease in catalytic activity.
The catalyst has drawbacks in its resistance to moisture such as by-product water, such as a decrease in the yield of azines per unit time. Although such drawbacks do not pose any operational problems even in the case of batch operations, various other disadvantages in addition to the above have been found when performing continuous reaction operations.

Namely, 1. Stable long-term continuous operation at a high reaction rate is difficult, 3. Precipitated copper salts have a strong corrosive effect, so stainless steel materials will cause pitting corrosion, and 3. Salt may adhere to the reactor wall or the reverse wave line of the reaction solution, causing crystal growth, 4. Side reactions may occur, and 5. The catalyst may be recovered by liquid-liquid extraction using, for example, ammonia water or ammonium chloride aqueous solution. If they do, it will be insufficient. As a method for overcoming the above-mentioned problems, the present inventors have previously discovered a method (Japanese Patent Application Laid-Open No. 103861/1983) of maintaining the water concentration in the reaction solution at 1000 ppm or less during continuous reaction operations. According to the patent, the moisture content in the gas phase coexisting with the reaction solution is 3 to 4v0.
Under conditions of a low concentration of 1%, the catalyst precipitates even at a pressure as low as 4 atmospheres.

In order to overcome this drawback, it is necessary to take measures such as increasing the amount of gas introduced into the reaction system in order to keep the moisture content in the gas phase coexisting with the reaction liquid low, and to compare the use of air as a source of molecular oxygen. When supplying a gas with a low oxygen concentration, it is necessary to operate the reaction under slightly increased pressure in order to obtain an industrially viable reaction rate, so even though this patent does not provide a satisfactory method, it is not necessarily a satisfactory method. hard. The present inventors have conducted extensive studies on a method for continuously producing azines from imines that is industrially easy to implement without the above-mentioned disadvantages, and as a result, in continuous reaction operation, The molar ratio between the imines present in the copper salt catalyst and the catalyst activity has a significant relationship with the resistance to water such as by-product water, the so-called water resistance of the catalyst, and the molar ratio is 1.5 or more. , preferably 2 or more, it has been found that even in reaction operations under pressure, an economical, long-term stable continuous reaction can be carried out without increasing the amount of gas introduced into the reaction system.

The present invention is based on this knowledge.

That's right. In the present invention, when benzophenone imines are oxidized with oxygen or oxygen-containing gas in the presence of a copper halide catalyst to continuously produce benzophenone azines,
Continuously supplying the raw material liquid and withdrawing the reaction liquid so as to maintain the molar ratio of benzophenonimines and copper chloride to benzophenonimines/halogen;copperide=1.5/1 or more, 90-230℃ while suppressing the reaction rate
There is a method for producing benzophenoneazines characterized by carrying out the reaction continuously. The molar ratio of benzophenone imines/copper halide in the present invention is 1.5/1 or more, preferably 2/1 or more.

According to the present invention, continuous reaction can be carried out stably for a long period of time without precipitation of copper salts. Moreover, it has the great advantage that stable continuous reactions can be carried out without increasing the amount of gas introduced into the reaction system. Enrichment of the water resistance of the catalyst is of great importance in the industrial production of azines by molecular oxygen oxidation of imines, and in the implementation of the process of the invention it is derived by precipitation of copper salts. Concerns about equipment corrosion have been alleviated; inexpensive stainless steel is sufficient; gas compression power costs have been improved by reducing the amount of molecular oxygen-containing gas introduced into the reaction system; There are great economic benefits, such as the simplification of the dehumidifier when dehumidifying and reusing gas.

Additionally, when benzophenone imine is oxidized to synthesize azine, a small amount of byproducts that cause benzophenone loss are generated, but the amount of these byproducts increases when the catalyst is deactivated by water in the system. do.

Therefore, stabilization of the catalyst is extremely significant in suppressing the loss of expensive benzophenones. In the present invention, imines are those represented by general formula (1), (formula (
R1 and R2 in 1) are a chain type, cycloaliphatic or aromatic hydrocarbon group having 1 to 10 carbon atoms, and an ether group consisting of the hydrocarbon group, an acyl group, an acyloxy group, an alkoxycarbonyl group, or a carboxylic acid amide group. groups, disubstituted amino groups, and groups that are the same or different from each other selected from the group consisting of halogen groups, hydroxyl groups, nitro groups, and cyano groups, or R1 and R2 taken together form a single bond or ring. May be expressed.

Also, M... n is 0 or an integer of 1-5. ) Specific examples include benzophenonimine, 2-, 3-, or 4-methylbenzophenonimine, 2-, 3-, or 4-ethylbenzophenonimine, 2-, 3-, or 4
-n1 and/or IsO-propylbenzophenonimine, 2-, 31, or 4-n1 and/or IsO1 and/or Tert-butylbenzophenonimine, 2-,
3- or 4-amylbenzophenonimine, 2-, 3
-, or 4-decylbenzophenonimine, 2-, 3-
, or 4-methoxybenzophenonimine, 4-cyclohexylbenzophenonimine, 4-phenylbenzophenonimine, 2●4-dimethylbenzophenonimine, 2●3-dimethylbenzophenonimine, 3●4-dimethylbenzophenonimine, 2●4-diethylbenzophenone imine, 2●3-diethylbenzophenonimine, 3●4-diethylbenzophenonimine, 2-methyl-4-ethylbenzophenonimine, 2-methyl-4
-Butylbenzophenone imine, 2.me, 3.3''-
, 4・4″-, 2・3″-, 2・4″-, or 3●4″
-dimethylbenzophenonimine, 2-, 3-, or 4
-Chlorobenzophenonimine, 2-chloro-4-methylbenzophenonimine, 4-kuchore 45-methylbenzophenonimine, 4●4″-dichlorbenzophenonimine, 4-nitrobenzophenonimine, 2●4-
Dinitropenzophenonimine, 4-hydroxybenzophenonimine, 4-N●N-dimethylaminobenzophenonimine, 4-acetylbenzophenonimine,
4-methoxycarbonylbenzophenonimine, 4-N
●N-dimethylcarbamoylbenzophenonimine, 4
-cyanobenzophenone imine, fluorenone imine,
Examples include xanthone imine, anthrone imine, and acridone imine.

Although the imine compound (1) used in the present invention is specifically illustrated, it goes without saying that other imines are also included.

Methods for producing these imines include, for example, a method in which the corresponding benzophenones are reacted with ammonia, a method in which benzonitriles are reacted with arylmagnesium bromide, which is a Grignard reagent, and a method in which they are produced by dehydration from diarylamino alcohol. Although there are various methods, imines obtained by any method can be used in this reaction. The imines used in the present invention, other than benzophenone, are benzophenone imines in which various substituents or substituents are combined to form a single bond or ring, but they are economically advantageous when carried out industrially. Preferred imines are benzophenone imines in which m and n are O, and benzophenone imines having one or two mono- or di-substituents.

In the present invention, copper halide is used as a catalyst,
Examples of halogens include chlorine, bromine, and iodine.
Chlorine is preferred.

Specific examples of copper halides include cuprous chloride, cuprous bromide, cuprous iodide, and the like. The present invention does not particularly require a solvent.

However, a solvent may be added to help dissolve the azines produced by the reaction and to maintain the reaction system in a solution state. A solvent that helps dissolve azines, which are products that are not easily oxidized in the ammoxidation reactions of benzophenones and imines, and is particularly preferably a solvent that is poorly miscible with water and has a low viscosity. For example, benzene, toluene, o-●m-●p-xylene, ethylbenzene, mesitylene, cumene, pseudocumene, amylbenzene, aromatic hydrocarbons having 6 to 16 carbon atoms and mixtures thereof, chlorobenzene, o-●m-● p-dichlorobenzene, nitrobenzene, o-●m-●p-dinitrobenzene, o
-●m-●p-chlorotoluene, diphenyl, phenanthrene, anisole, diphenyl ether, acetophenone, benzyl, benzophenone, hexane, heptane, cyclohexane, cyclooctane, ethylcyclohexane, ethylene dichloride, tetrachlorethylene, diisopropyl ether, dipropyl ether, Examples include diisobutyl ketone, butyl acetate, butyl benzoate, phenyl benzoate, dimethyl phthalate, and the like. In the present invention, it is usually preferable to use an imination reaction solution of benzophenones as the imine; in this case, since unreacted benzophenones act as a solvent, it is not necessarily necessary to add a solvent. The reaction temperature of the present invention is 90 to 230°C. The reaction time cannot be uniformly specified because it depends on the amount of catalyst used, but it is usually in the range of 0.1 to several tens of hours. When using a large amount of catalyst, the reaction rate is high, but the achieved imine conversion rate must be kept low.On the other hand, when a small amount is used, the reaction rate is slow, so temperature, pressure, reaction time, and other reaction rates are affected. It is determined depending on the factors (giving a
pm is preferably used.

As molecular oxygen, oxygen gas alone may be supplied to the reaction system, or a mixed gas containing an inert gas such as nitrogen and oxygen gas, such as air, may be used.

There are no particular restrictions on the pressure, whether it is reduced pressure, normal pressure, or increased pressure, but
When oxygen gas alone is used, a pressure of 1 to 20 atm is appropriate, and when air is used, a pressure of about 1 to 4 pm is appropriate. The oxygen gas or mixed gas containing oxygen gas may be supplied to the reactor in either a flow type or a closed type, but a blow flow type is preferable in order to suppress hydrolysis of imines by reaction product water. Further, it is preferable to use dried oxygen gas or a mixed gas containing oxygen gas.

The present invention overcomes the drawbacks of the known methods, which are difficult to implement industrially for the reasons mentioned above.According to the present invention, there are no operational problems, catalyst recovery is easy, and imine production is economically advantageous. can be continuously produced by oxidizing the corresponding azines.

According to the present invention, unreacted imines remain in the reaction solution, but the unreacted imines can be classified into ammonia and benzophenones without decomposing azines.
, which can be used in the synthesis of imines, which are the raw materials of the present invention.
Hereinafter, this will be explained in detail using examples.

Example 1 Thermocouple sheath tube, ring spargeer for gas injection, gas outlet, imine liquid supply port, reaction liquid! 170 g of the raw material liquid was charged into a 300 ml glass autoclave equipped with an overflow tube, a pressure gauge, and a magnetic stirrer.

The raw material solution was prepared as follows. A raw material solution was prepared by dissolving cuprous chloride corresponding to 2500 ppm of Cu in a solution containing 23.4% benzophenone imine and the remaining total amount being benzophenone. Next, the solution was heated externally using electric heat to maintain the liquid temperature at 120'C.

While stirring, air was supplied at a flow rate of 0.27 eImin (volume under normal pressure, hereinafter referred to as NTP) while maintaining the pressure in the system at 4 atm; 1. Time batch reactions were performed. After the batch reaction was completed, a plunger pump was used to start supplying the raw material liquid at a rate of 85 fI per hour, and the reaction was continued for 7 hours under the same conditions with air at 0.27 e1 min (NTP). Ta. The waste gas containing water vapor after the reaction is led to the cooler through the gas vent located in the upper flange of the reactor, and after condensing the accompanying benzophenone, the atmospheric pressure is reduced and released into the atmosphere. did.

The reaction solution was continuously extracted to the outside at a rate of 85 yards per hour using a pump.

The resulting reaction solution had a transparent reddish-brown color, and no cupric salt precipitation was observed therein. The average residence time of the liquid was 2 hours, and the average reaction rate of benzophenonimine was 93.
．． The selectivity to benzophenone azine was 99%, and the molar ratio of Cu to benzophenone imine in the reaction solution was benzophenone imine/CU=2.0.

Further, the average moisture content in the off-gas was 6.9%.

Comparative Example 1 The Ctl concentration in the raw material liquid was 4000 ppm, and the supply amount of the raw material liquid and the withdrawal amount of the reaction liquid were 74y1hr1 and the air was 0.
．． 3e1min1 average residence time2. Example 1 except that the time, the average reaction rate of benzophenone imine was 95.5%, and the molar ratio of benzophenone imine to Cu in the reaction solution was set to benzophenone imine/CU = 0.92.
I did the same thing.

Claims (1)

[Claims] 1. When continuously producing benzophenone azines by oxidizing benzophenone imines with molecular oxygen or molecular oxygen-containing gas in the presence of a copper halide catalyst,
In order to maintain the molar ratio of benzophenonimines and copper halides to benzophenonimines/copper halide = 1.5/1 or more, the raw material liquid is continuously supplied and the reaction liquid is withdrawn to increase the reaction rate. A method for producing benzophenoneazines, characterized by carrying out the reaction continuously at a temperature of 90 to 230°C while suppressing the reaction.