JPS6319503B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing nitrophenylaminophenyl ethers. Nitrophenylaminophenyl ethers are compounds useful as medicines, agricultural chemicals, and raw materials for synthetic resins. Japanese Patent Publication No. 47-18101 is known as a method for producing these compounds, in which alkali metal salts of aminophenols and chloronitrobenzene are used as raw materials, dimethylformamide or the like is used as a solvent, and 50 to
A method of reacting at 110°C is disclosed. According to this method, the reaction temperature can be kept relatively low and side reactions can be suppressed, but the reaction rate is also low. In addition, in Japanese Patent Publication No. 55-40573, as a preliminary step to producing diaminodiphenyl ether, dimethylformamide is used as a solvent, and an alkali metal salt of aminophenol and halonitrobenzene are reacted under reflux to produce nitrophenylaminophenyl ether. A method of manufacturing is disclosed. An example of the reaction temperature in this method is 145°C to 149°C, but the reaction rate is still low, and according to the specific example, a reaction time of 5 to 6 hours is required. As a result of studies aimed at improving the reaction rate in the condensation reaction of aminophenols and halonitrobenzenes and improving the selectivity of nitrophenylaminophenyl ethers, the present inventors found that
By performing the condensation reaction while removing water produced by the condensation reaction from the reaction system by distillation, or by performing the condensation reaction while removing it from the reaction system as an azeotrope with a hydrocarbon, The inventors have found that the above object can be achieved and have arrived at the present invention. That is, the present invention provides a method in which a condensation reaction is carried out under heating conditions in the presence of aminophenols, nitrohalobenzenes, an aprotic polar solvent, and an alkali metal carbonate. The gist of the first invention is a method for producing nitrophenylaminophenyl ethers, characterized in that the condensation reaction is carried out while removing aminophenols and nitrohalobenzenes from the reaction system by distillation. In a method in which a condensation reaction is carried out under heating conditions in the presence of an aprotic polar solvent and an alkali metal carbonate, a hydrocarbon is present in the reaction system, and the water produced by the condensation reaction is mixed with the hydrocarbon. The gist of the second invention is a method for producing nitrophenylaminophenyl ethers, characterized in that the condensation reaction is carried out while removing the nitrophenylaminophenyl ethers from the reaction system as an azeotrope. Specifically, the aminophenols used in the present invention include p-aminophenol, m-aminophenol, o-aminophenol, or compounds in which the benzene nuclear hydrogen of these is further substituted with a lower alkyl group such as a methyl group or an ethyl group. Among them, p-aminophenol and m-aminophenol are preferably used. On the other hand, specific examples of halonitrobenzenes include chloronitrobenzenes such as p-chloronitrobenzene, m-chloronitrobenzene, and o-chloronitrobenzene, and bromonitrobenzenes such as p-bromonitrobenzene, m-bromonitrobenzene, and o-bromonitrobenzene. ,p-
Fluoronitrobenzenes such as fluoronitrobenzene, m-fluoronitrobenzene, o-fluoronitrobenzene, p-iodonitrobenzene, m-
Examples include iodonitrobenzenes such as iodonitrobenzene and o-iodonitrobenzene, and compounds in which hydrogen atoms in the benzene nucleus are substituted with lower alkyl groups such as methyl and ethyl groups. Among these, chloronitrobenzenes are preferred, and p-chloronitrobenzene and m-chloronitrobenzene are particularly preferred. Specifically, an aprotic polar solvent is used as the solvent, such as dimethylformamide, dimethylacetamide, dimethylsulfoxide, sulfolane, N-methyl-2-pyrrolidone, hexamethylphosphoramide, acetonitrile, and the like. Specific examples of alkali metal carbonates include sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, and bicarbonates such as sodium hydrogen carbonate and potassium hydrogen carbonate. In the present invention, specific examples of the hydrocarbons present in the reaction system include aromatic hydrocarbons such as benzene, toluene, and xylene, aliphatic hydrocarbons such as hexane, heptane, and octane, and fats such as cyclohexane and methylcyclohexane. Examples include cyclic hydrocarbons. The ratio of the solvent and alkali metal carbonate to the aminophenols and halonitrobenzenes in the reaction of the present invention is arbitrary, but usually the ratio of the solvent to 1 mole of the sum of the moles of the aminophenols and halonitrobenzenes is about 200%. or about 2000ml,
The amount of alkali metal carbonate is about 0.5 to about 2 moles. In the method of the present invention, the condensation reaction is carried out at a temperature in the range of about 110 to about 150°C, preferably 130 to 150°C, and distillation removal of water or azeotropic distillation removal of hydrocarbons and water from the condensation reaction system can occur. under temperature conditions. Furthermore, the pressure during the condensation reaction may be any condition as long as it can cause distillation removal of water from the reaction system or azeotropic distillation removal of hydrocarbons and water in relation to the reaction temperature. It does not matter whether it is under normal pressure conditions or under reduced pressure conditions. In the first method of the present invention, in the method of removing water produced by the condensation reaction by distillation, water is removed directly from the reaction system using a distillation device such as a distillation column directly connected to the reaction system. A method of distillation is adopted. In this case, distillation removal can be carried out under reflux, or distillation removal can be carried out without reflux. In the second method of the present invention, a hydrocarbon is present in the reaction system, and the water produced by the condensation reaction is formed with the hydrocarbon to form an azeotrope and removed from the reaction system while the condensation reaction is carried out. will be implemented. The hydrocarbon may be supplied to the reaction system before or during the condensation reaction.
In particular, it is desirable to supply hydrocarbons continuously or intermittently during the condensation reaction. The feed rate can be varied depending on the amount of water produced, and is usually about 40% to about 200% of the total weight of the raw materials aminophenols and halonitrobenzenes.
It is desirable to continuously or intermittently supply approximately 40% to approximately 200% of the distillate from the reaction system. According to the present invention, the condensation reaction between aminophenols and halonitrobenzenes is efficiently carried out, and nitrophenylaminophenyl ethers can be selectively produced. In order to obtain nitrophenylaminophenyl ethers from the reaction mixture obtained by the condensation reaction of the present invention, separation methods such as distillation, extraction, and crystallization can be employed. Further, nitrophenylaminophenyl ethers can be converted into diaminodiphenyl ethers by hydrogen reduction in the presence of a catalyst such as palladium or platinum, either as a reaction mixture or after separation. Next, examples will be shown. In addition, in the example, m-
Conversion rate of aminophenol and 3-amino-
The selectivity of 4'-nitrodiphenyl ether is a value determined by direct gas chromatographic analysis of the reaction mixture. Example 1 38 g (0,275 mol) of potassium carbonate and 300 ml of dimethylformamide were charged into a 14-necked flask equipped with a rotary stirrer, a thermometer, a dropping funnel, and a distillation column (10-stage sieve tray column), and the mixture was heated to 150 mL in an oil bath. heated to ℃. On the other hand, m-
A solution was prepared in which 55 g (0.5 mol) of aminophenol and 80 g (0.5 mol) of p-chloronitrobenzene were dissolved in 200 ml of dimethylformamide. When the reaction flask reached a predetermined temperature, the raw material liquid from the dropping funnel was started to be added to start the reaction. The dropping of the raw material was completed in 1 hour. After the dropwise addition was completed, the reaction was continued for an additional 1.5 hours. On the other hand, with the start of the reaction, a portion of the reflux liquid began to be withdrawn from the top of the distillation columns. The distillate drawn out during the total reaction time was 20 ml, and the concentration of water in the distillate was 22%. After the reaction was completed, the condensation reaction solution was analyzed by gas chromatography, and the reaction results showed a conversion rate of m-aminophenol of 98.0 mol% and a selectivity of 3-amino-4'-nitrodiphenyl ether of 99.0% mol%. It was hot. After separating the inorganic salt from the reaction mixture of the above condensation reaction, 1 g of 5% Pd/C was added, and hydrogen was blown into the mixture at a flow rate of 12/hr at 130°C and normal pressure. After blowing hydrogen for 4 hours, the hydrogenation catalyst was removed and the reaction solution was concentrated. The resulting pot residue was distilled under conditions of 2 mmHg and 200°C to obtain 95.5 g (0.477 mol) of 3,4'-diaminodiphenyl ether. The yield based on m-aminophenol was 95.5 mol%. Example 2 55 g (0.5 mol) of m-aminophenol, 80 g (0.5 mol) of p-chloronitrobenzene, and 38 g (0.275 mol) of potassium carbonate were added to a reaction flask along with 500 ml of dimethylformamide, and the reaction was started at 140°C. At the same time as the reaction starts, add 40% benzene.
The benzene was fed continuously at a rate of ml/hr, and at the same time, a distillate of approximately the same amount as the benzene fed was continuously extracted. The reaction results of this condensation reaction are shown in Table 1.

[Table] After the inorganic salts were separated from the reaction mixture obtained by carrying out the condensation reaction for 3 hours, it was worked up in the same manner as described in Example 1. The amount of 3,4′-diaminodiphenyl ether obtained after distillation was 96.0 g (0.48 mol).
The yield was 96 mol% based on the m-aminophenol used. Example 3 In Example 2, hexane was used instead of benzene, and the reaction was carried out at 130°C. The reaction results were as follows. Condensation reaction time: 4 hours MAP conversion rate: 98.3 mol% ANPE selectivity: 99.5 mol% This condensation reaction solution was post-treated by the method described in Example 1, and as a result, 96.2 g of 3,4'-diaminodiphenyl ether was obtained. Yield based on raw material MAP is
It was 96.2 mol%. Example 4 The same procedure as in Example 2 was conducted except that cyclohexane was used instead of benzene. The results of the condensation reaction were as follows. Condensation reaction time 3.5 hr MAP selectivity 98.0 mol% ANPE selectivity 99.5 mol% Comparative example 1 Everything is the same as Example 2 except that in Example 2, benzene was not fed and water was not removed from the reaction system. It was done under certain conditions. The reaction results are shown in Table 2.

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Claims (1)

[Scope of Claims] 1. In a method of carrying out a condensation reaction of aminophenols and nitrohalobenzenes in the presence of an aprotic polar solvent and an alkali metal carbonate under heating conditions, the product produced by the condensation reaction A method for producing nitrophenylaminophenyl ethers, characterized in that the condensation reaction is carried out while removing water from the reaction system by distillation. 2 In a method of carrying out a condensation reaction of aminophenols and nitrohalobenzenes under heating conditions in the presence of an aprotic polar solvent and an alkali metal carbonate, a hydrocarbon is present in the reaction system to carry out the condensation reaction. A method for producing nitrophenylaminophenyl ethers, characterized in that the condensation reaction is carried out while the water thus produced is removed from the reaction system as an azeotrope together with the hydrocarbon.