JPS58131944A - Preparation of aniline derivative - Google Patents

Abstract

PURPOSE:To obtain an aniline derivative useful as a raw material for medicines and agricultural chemicals, by reacting an acetanilide derivative with water in the presence of a small amount of an acidic catalyst in an alcoholic solvent, and adding an alkali in an amount of gram equivalent equal to the acidic catalyst to the resultant reaction solution. CONSTITUTION:A compound of formulaI(R1 is H or halogen; R2 is halogen) is reacted with water in the presence of an acidic catalyst, e.g. hydrochloric acid or sulfuric acid, in an amount of 0.1g equivalent or less based on the above- mentioned aniline derivative in an alcoholic solvent at 140 deg.C or above, preferably 160-180 deg.C, and an alkali in an amount of gram equivalent equal to the acidic catalyst is added to the reaction solution to give the amied compound of formula II. The solvent is required to dissolve the compound of formulaI, water and hydrochloric acid and be stable to the acid and heat. n-Hexanol, ethylene glycol, etc. having >=140 deg.C boiling point is usually used as the solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the production of an aniline derivative represented by the general formula by hydrolysis of an acetanilide derivative represented by R3 represents a halogen atom and R3 represents a halogen atom. Aniline derivative (1) is a substance useful as a raw material for medicines and agricultural chemicals. For example, the production of useful compounds with high unveiling activity using 2,4-dichloroaniline as a raw material was disclosed in JP-A-56-128.
743. It is described in JP-A-55-98144.

As a production method for 2.4-dichloroaniline, Arki
v For Kemi 21(28) 301-JO8
(1963), acetanilide is chlorinated in an acetic acid solvent to form 2,4-dichloroacetanilide, and then 46 times the molar amount of the acetanilide is reacted with salt #k, and 2,4-dichloroaniline is used. Salt is manufactured in # of salt.

Journal Of Am5rican Ch
emical 5OC1et7+ga, 934~41 (
(1957) describes that 2,4-dichloroaniline was produced by hydrolysis of 2,4-dichloroacetanilide in an ethanol solvent in the presence of an acid, but the details of the reaction conditions were not disclosed. do not have.

Therefore, the present inventors hydrolyzed 2,4-dichloroacetanilide as an example in an ethanol solvent at 80° C. in the presence of hydrochloric acid. As a result of 7, hydrolysis of 2,4-dichloroacetanilide requires 1 of the acetanilide.
．． One gram equivalent of hydrochloric acid was required, and t1 gram equivalent of sodium hydroxide was required to recover the aniline from the hydrochloride of 2,4-dichloroaniline produced.

As described above, the hydrolysis of the acetanilide derivative (1) usually requires an acid in an amount equal to or more than the same gram of the acetanilide, and the aniline derivative (11) is obtained as a salt. Therefore, aniline derivative (1)? The K to be collected is
An alkali of equal or greater strength to the aniline salt must be used.

That is, the known method has the disadvantage that an acid of 1 gram equivalent or more and an alkali of 1 gram equivalent or more must be used to produce 1 mole of aniline derivative (II).

With the aim of overcoming such drawbacks and establishing an industrial manufacturing method for the aniline conductor (jl), the present inventors conducted various tests and made extensive studies. In the presence of an acid catalyst of 11 grams or more,
It was discovered that aniline conductor (It) can be produced in good yield by reacting it with water at 140° C. or higher in an alcoholic solvent, and then adding an alkali f equivalent to an acid catalyst to the reaction solution, and the present invention completed.

According to the present invention, in the hydrolysis of the acetanilide derivative (1), it is only necessary to use not more than 1 acid per 11 grams of said acetanilide, and therefore, when recovering the aniline derivative (II), less than 1 acid per 1 gram of said acetanilide can be used. It is sufficient to use the above alkalis.

In carrying out the present invention, acetanilide derivatives (
(2) React with water at a predetermined temperature at 140° C. or higher in an alcoholic bath medium in the presence of an acid catalyst of 1 mole or less per gram of α. Then, a mixture f of the sweetfish derivative (II) and the aniline salt is obtained. The reaction is complete within 2 hours.

In order to recover the aniline from the aniline derivative (1), #i, an alkali equal to or more than Durham equivalent of the acid used in the hydrolysis of the acetanilide derivative (summer) is added.

The acid used in the present invention is selected from strong inorganic acids such as hydrochloric acid and sulfuric acid, and may be used in an amount of 1 or less per 11 grams of the acetanilide derivative (1).

As the heating medium, the raw material acetanilide derivative 0) is used.

Water, hydrochloric acid? It needs to be soluble and stable against dispersion and heat. For this purpose, alcohol is chosen. but,
Lower alcohols such as methanol and ethanol have low boiling points, so the reaction rate is very low in the presence of a catalytic acid.The reaction rate in lower alcohols in the presence of an acid equivalent to or more than the equivalent of acetanilide derivative (1) In order to obtain a reaction rate equivalent to that of tKIr, a reaction temperature of 1140° C. or higher is required.

Therefore, 1 n-hexanol, octatool, and ethylene glycol usually have a boiling point of 140°C or higher.

Alcohols such as propylene glycol and diethylene glycol are used. However, lower alcohols such as methanol and ethanol may be used as long as they can be heated to a temperature above the boiling point using a pressure reactor or the like.

Increasing the reaction temperature increases the reaction rate, but temperatures that are too high do not provide any benefit.

At temperatures below 140°C, the reaction rate is low as mentioned above;
Therefore, it is usually 140 to 200℃, preferably Fi160
~180°C.

As the alkali added to the reaction solution after the reaction is completed, sodium hydroxide, potassium hydroxide, calcium hydroxide, etc. are sufficient.

The present invention will be described in detail with reference to Examples below, but the present invention is not limited to these Examples.

Example 1 5 equipped with a chlorine gas blowing pipe, a thermometer insertion pipe, and a cooler
50gt of acetanilide in a 00m separable flask
#180 vinegar and 20% water were taken, and chlorine gas was blown into the solution at 25 to 30°C. After blowing in a predetermined amount of chlorine gas,
51.2 gi of precipitated 2,4-dichloroacetanilide
I took over.

Next, 12 gt of λ4-dichloroacetanilide and 5 gt of 36% hydrochloric acid were placed in a 100-sized eggplant-shaped flask.

6 parts of water and 56 parts of ethylene glycol were taken, a reflux condenser was attached, and the mixture was heated at 160°C for 2 hours.

After the reaction is completed, let it cool and 48% hydroxide) IJum aqueous solution [14gz] was added to the reaction solution and the reaction solution was mixed with water 505w/
9. 2,4-dichloroaniline was washed out and precipitated.
5gx'lrF was taken.

The yield of 2.4-dichloroaniline was 97.6% based on 2.4-dichloroacetanilide.

Example 2 λ4- produced in Example 1 was placed in the same reactor as Example 1.
Dichloroacetanilide 12μ, 98% - concentrated sulfuric acid α2g
Take z, 8gz of water, 40WIt of ethylene glycol,
Heated at 180°C for 1.5 hours.

After the reaction was completed, the mixture was allowed to cool and a 48% hydroxide solution (L4gz) was added to the reaction mixture.

When the reaction solution was analyzed by gas chromatography, λ
19.4 gL of 4-dichloroaniline was produced.

The yield of 2.4-dichloroaniline was 9a6% based on 2.4-dichloroacetanilide.

Examples 3 to 6 In the same reaction apparatus as in Example 1, acetanyl IJ derivatives,
56%-hydrochloric acid, water, and a solvent were taken and reacted under the reaction conditions shown in Table 1.

After the reaction was completed, the mixture was allowed to cool and a 50% potassium hydroxide water bath was added, and the reaction solution was analyzed by gas chromatography to determine the amount of aniline-induced rod produced.

The results are shown in Table 1.

Comparative Ga 1 The reaction apparatus of Examples 1 and 4 was prepared in Example 1.
-Dichloroacetanilide 12gz, 36% -HCl α5
Take EL, 6μ of water, and 30μ of ethanol.

The mixture was heated under reflux for 2 hours. After the reaction was completed, the reaction solution was allowed to cool and 48% hydroxylated (48%) of IJum aqueous solution was added to the reaction solution. When the reaction solution was analyzed by gas chromatography,
2,4-dichloroaniline II'iA4gt was produced. The yield of 2.4-dichloroaniline was 357% based on 2゜4-dichloroacetanilide. Comparative Example 2 The same reaction apparatus as Example 1 was used to produce 2,
4-dichloroacetanilide 12μ, 36 Qi salt @15
Fresh water, 6 fresh water, ethylene glycol 361It1-take,
It was heated at 130°C for 2 hours. After the reaction is completed, let it cool 48
% - hydroxide) IJum aqueous solution α4 was added to the reaction solution - When the reaction solution was analyzed by gas chromatography, it was found that 2
, 4-dichloroaniline produced 59μ of -C. 2.
The yield of 4-dichloroaniline was 61.9% based on 2.4-dichloroacetanilide.

Patent applicant: Toyo Soda Kogyo Co., Ltd.

Claims (1)

[Claims] is a halogen atom, and bird is a halogen atom) is reacted with water at 140°C or higher in an alcoholic solvent in the presence of an acid catalyst of not more than 11 gram equivalents of the anilide, and then reacted with water at 140° C. or more of an acid catalyst of not more than 11 gram equivalents. A method for producing an aniline derivative represented by the general formula, which comprises adding an alkali of to the reaction solution.