JPS5912659B2 - Method for producing N-phenyl-2,6-dichloroaniline - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-yield and easy production method for N-phenyl-2.6-dichloroaniline.

2,6-dichlorophenylaniline was published in the Special Publication Act in 1972-23.
Analgesic and anti-inflammatory agent O-(2.6-
It is an important intermediate in the production of sodium dichloroanilino)phenylacetate.

As a method for producing N-phenyl-2/6-dichloroaniline, Japanese Patent Publication No. 42-23418 describes a method in which 2,6-dichloroacetanilide and bromobenzene are refluxed for two days, further treated with an alkali, and then distilled to obtain a yield of 43%. Then, 2,6-dichloroaniline and 2-chlorobenzoic acid were reacted to produce N-2,6 dichlorophenylanthrawanilic acid with a yield of 23%, which was further decarboxylated at 280°C and then distilled. Two methods for obtaining N-phenyl 2,6-dichloroaniline are described. In both methods, the yield is low, the number of steps is 2, the production method is complicated, and the Iθ reaction is industrially difficult.

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According to 97729(1-2) 120-1, 2,6-dichloroaniline and iodobenzene are dissolved in nitrobenzene.
The reaction was carried out at 10° C. for 12 hours, and N-phenyl-2.6-zig15 loloaniline was obtained in a yield of 56%, but the yield was not sufficient. Further, the temperature of 210° C. is a temperature at which it is difficult to react with general-purpose industrial equipment. The present invention is characterized by improving the drawbacks of these production methods and producing N-phenyl-2.6-dichloroani20 phosphorus in a high yield in one step. The present invention will be explained below. Add 2.6 to dichloroaniline, iodobenzene, an inorganic copper compound such as metallic copper or copper chloride as a catalyst, an acid acceptor such as an alkali metal carbonate, and 25 a solvent to the reactor, and heat at 130 to 180°C for 5 minutes.
After reacting for ~15 hours, the reaction mixture is cooled, the lower solution is separated, the solvent is distilled off under residual pressure, and N-phenyl-2.6-dichloroaniline is isolated by distillation.

In this reaction, the solvent and catalyst are important factors.

30 Depending on the solvent, the reaction rate is slow and the formation of N-N-diphenyl-2.6-dichloroaniline as a side reaction product cannot be suppressed.

Dimethylsulfoxide, dimethylformamide, or 1,3-dimethyl-2-imidazolidinone has a high reaction rate and provides the desired product in high yield. Also, 2.
The amount of 6-dichloroaniline used is 1.
Use 0 to 2.0 mol. From an economic point of view, this amount is preferably equimolar, but in reality, N-N
-diphenyl-2,6-dichloroaniline is produced, and preferably 1
．． It is 2 to 1.5 times the mole. Excess amount of 2,6-dichloroaniline is removed during solvent distillation or N-phenyl△2.
Almost the entire amount is recovered during the distillative isolation of 6-dichloroaniline. The reaction temperature is 130 to 180°C, and is preferably 160 to 180°C because the lower the reaction time, the longer the reaction time. As a catalyst, a copper compound is usually used, and an inorganic copper compound such as metallic copper or copper halide is used. Without this catalyst, the reaction would be very slow and the desired product would hardly be obtained. The isolation method is that after the reaction is completed, the inorganic salt is separated and the solvent is removed under reduced pressure.
-Dichloroaniline and N-phenyl 2,6-dichloroaniline are fractionally distilled, or water and a solvent such as toluene are added to the reaction solution, insoluble materials are separated and the toluene layer is extracted, under reduced pressure, toluene, etc. There is a method of distilling off the solvent and then fractionating 2,6-dichloroaniline and N-phenyl-2,6-dichloroaniline. This will be explained in detail in Examples below.

Example 1 2,6-dichloroaniline 24.3f iodobenzene 20.41, potassium carbonate 20V1 dimethyl sulfoxide 601, and metallic copper 1t were added to the reactor,
After reacting at ℃ for 10 hours, the inorganic salts were separated from the reaction solution,
Furthermore, inorganic salts were washed with toluene 501, toluene was distilled off from liquid f under reduced pressure, and dimethyl sulfoxide, 2.
After distilling off 6-dichloroaniline, N-phenyl-2
・6-dichloroaniline at 14'C/0.2mTfLH
19.8V was obtained as a fraction of g.

Example 2 A reactor was charged with 243y of 2,6-dichloroaniline, 6007 dimethyl sulfoxide, 200V1 of potassium carbonate, and 10y of metallic copper, heated to 150 to 160°C, and 517 iodobenzene was added 4 times every 2 hours, after the final addition. The temperature was maintained for 6 hours.

After cooling, add 1000y of water and 1500y of toluene, remove insoluble matter, extract the toluene layer, and add 500y of water.
Washed twice with After that, toluene was distilled off under reduced pressure.
・6-dichloroaniline and N-phenyl 2,6-dichloroaniline are fractionated at 140-145℃/0.271
&1LHg fraction 2167 was obtained as N-phenyl-2,6-dichloroaniline. Example 3 Add 24.3 f of 2,6-dichloroaniline, 20.4 y of iodobenzene, 20 t of potassium carbonate, 607 y of dimethyl sulfoxide, and 1 t of copper chloride to a reactor and heat at 150-160°C.
After reacting for 5 hours, the inorganic salt was separated from the reaction solution, the inorganic salt was further washed with 50y of toluene, the toluene was distilled off from the solution under reduced pressure, and dimethyl sulfoxide and 2,6-dichloroaniline were further distilled off. After that, 20y of N-phenyl-2,6-dichloroaniline was obtained as a fraction at 140°C/0.2711mHg.

Claims (1)

[Claims] 1 2,6-dichloroaniline and iodobenzene in the presence of an acid acceptor and a copper compound,
A method for producing N-phenyl-2,6-dichloroaniline, which comprises reacting in dimethylformamide or 1,3-dimethyl-2-imidazolidinone. 2. The method for producing N-phenyl-2,6-dichloroaniline according to claim 1, wherein the copper compound is metallic copper or an inorganic copper compound.