JPS58134055A - Production of 5-chloro-2-nitroaniline or 4-nitro-m- phenylenediamine - Google Patents

Abstract

PURPOSE:The reaction of 2,4-dichloronitrobenzene with ammonia is followed by action of a mineral acid on the product to give the titled compound used as a starting material of dyes with industrial advantage. CONSTITUTION:The reaction of 2,4-dichloronitrobenzene with amonia gives a mixture of 5-chloro-2-nitroaniline (abbreviated to CNA hereinafter) and 4-nitro- m-phenylenediamine (abbreviated to NPDA), then a mineral acid such as hydrochloric or sulfuric acid is made to act on the mixture to form a mineral acid salt of NPDA and effect separation into CNA and NPDA. The above ammonolysis is effected at 50-200 deg.C and this reaction forms both of CNA and NPDA simultaneously. Further, CNA and NPDA have different reactivity with mineral acids due to the difference in the position of amino groups to nitro groups. Namely, NPDA more readily forms a mineral acid salt and the salt is soluble in water, thereby facilitating their separation.

Description

Detailed Description of the Invention The present invention d, '2,4-dichloronitrobenzene (hereinafter referred to as 2
．． 4-DCNB) to 5-chloro-2-nitroaniline (hereinafter abbreviated as CNA) and 4-nitro-
The present invention relates to a method for producing m-phenylenediamine (hereinafter abbreviated as NPDA).

CNA and NPDA are useful as raw materials for dyes, medicines, agricultural chemicals, and the like. Generally, CNA is (a) 3-
Saponification of 5-chloro-2-nitroacetanilide obtained by nitration of chloroacetanilide, (b) Nitration of 3-chloroaniline with hydrochloric acid, (c) 2.4-D
NPDA can be treated by methods such as ammonolysis of CNB, (a) nitration of diacetyl-m-phenylenediamine, (b) heating of 4-nitroaniline-3-sulfonic acid with ammonia, and (c) 2,5- It has been described in the literature that it cannot be obtained by methods such as partial reduction of dinitroaniline with ammonium sulfide and oxidation of 14-nitroso-m-phenylenediamine with 3M hydrogen oxide. However, in these methods, raw materials are expensive, the manufacturing process is complicated, or the yield and purity are low, so it has been difficult to obtain CNA and NPDA industrially.

The present inventors focused on the above-mentioned ammonolysis of 2.4-DCNB and proceeded with further investigation, and found that (1) in this ammonolysis, not only CNA but also NPDA is generated at the same time; (2) CNA and NPDA are high melting point substances (melting point - CNA; 126.5℃, NPDA; 161℃
), and both contain a nitro group, making it difficult to apply ordinary methods such as crystallization and distillation to separate them; (3) the amino There is a difference in reactivity with mineral acids depending on the position of the group, and NPDA, which has an amino group at the P-position relative to the nitro group, is more likely to form salts with mineral acids than CNA, which does not have it. , (4) Since this mineral salt of NPDA is water-soluble, it is easy to separate the two.Furthermore, we have obtained the knowledge that CNA and NPDA can be obtained as highly pure products, and this book- This is a completed version of the first method.

That is, the method of the present invention involves reacting 2,4-dichloronitrobenzene with ammonia to produce a mixture containing 5-chloro-2-nitroaniline and 4-nitro-m-phenylenediamine, and adding a mineral acid to the mixture. to form a mineral acid salt of 4-nitro-m-phenylenediamine, and 5-chloro-2-nitroaniline and 4-nitro-
5-chloro-2-nitroaniline-spanning 4-nitro-m, characterized in that it is separated from m-phenylenediamine.
- A method for producing phenylenediamine.

In the method of the present invention, 2.4-1) CNB and ammonia are first reacted to produce a mixture containing CNA and N))DA. This ammonolysis is usually 50~
2.4-DCNB at 200℃ preferably 80-180℃
This is carried out by reacting the aqueous ammonia solution with an ammonia aqueous solution, and the reaction time is suitably 2 to 10 hours. This reaction Ft
1:''・,・1 It may be carried out under the presence of a copper-based catalyst, but the presence of 1,000 is not necessarily necessary, and it is usually carried out in an added state.Aqueous ammonia solution Toshi Crt normal, 20-5
A concentration of 0% by weight was used, and this was combined with 2.4-DC
It is used in an equal amount of 8 to 20 times the molar amount of NB in terms of NHs. In addition, in this reaction, the production ratio of CNA and NPDA can be changed by appropriately selecting the reaction conditions. For example, if the reaction is carried out at a high reaction temperature, a long reaction time, and a large amount of ammonia, Compared to CNA, the amount of NPDA produced is larger, specifically 2.4
- using 16 times molar ammonia to DCNB,
When the reaction is carried out at 170° C. for 6 hours, a reaction product containing mostly NPDA and almost no CNA is obtained. Conversely, if relatively mild reaction conditions were used and the amination reaction did not proceed as much, CNA compared to NPDA.
A reaction product containing a large amount of is obtained.

Next, in the method of the present invention, the mixture is treated with a mineral acid to separate 'NPDA and CNA.

With this mineral acid treatment, NPDA reacts with the mineral acid to form water-soluble salts, whereas CNA is salt-forming and does not dissolve in water, so simple measures such as overburdening can do both. Compounds can be easily separated.

As the mineral acid, acids such as sulfuric acid and hydrochloric acid are used, and this is usually reacted with the above mixture at 30-90°C for 7 hours and at 50-80°C for 0.2-2 hours. The ratio of the amount of the mixture to the mineral acid is preferably in the range of 50 to 20 g of the mineral acid per 10 g of the mixture, but it is preferable to use a mineral acid with a concentration of 2 to 20%. If the temperature during the reaction between the mixture and mineral acid becomes higher than the above range, or if the amount of mineral acid used increases, the concentration of CNA in the aqueous solution increases, and the concentration of CNA in the aqueous solution increases, resulting in a loss of 1 flt of recovered NPDA. Furthermore, if the temperature becomes low or the amount of mineral acid used is small, NPDA will remain in the CNA, which is also undesirable because the purity of the CNA will decrease.

The mineral acid salt of NPr)A in the solution obtained as described above is then neutralized with an alkali if necessary, filtered, washed and dried to liberate NPDA. In addition, CNA as a filter cake can be obtained by washing and drying1, and according to the method of the present invention, CNA and NP
DA has a high yield of 90% or more in total (2,4-DC
NB standard), and their purity is, for example, 95
% or more.

Example 1 Purification 2 was placed in a 500 il/stainless steel autoclave.
．． 4-DCNB (6 items of methanol reconsolidation) 58g and 2
291 g of 8% by weight ammonia aqueous solution (291 g as Nus)
．． 16 times the mole of 4-DCNB) was added thereto and heated to 150°C. After reacting at this temperature for 6 hours, excess ammonia was removed and the mixture was cooled to 30° C. with thorough stirring. The reaction product was washed once and dried to obtain 51 g of a reaction product.

Analysis of this product by gas chromatography revealed that it contained 31.4% CNA, 17.0% NPDA, and 1.6% other components. Next, put 50 g of this reaction product into a beaker and add 10% 1''1:.

of sulfuric acid was added, heated to 60°C, and reacted for 30 minutes. Thereafter, the solution was neutralized with sodium hydroxide, washed and dried to obtain 9.5 g of NPDA. In addition, 1 filter cake was washed and dried with CN A 40
．． 0 g was obtained. Regarding these yields (2,4-DCNB standard), NPDA is 20.2% and CNA is 76.0%.
Also, regarding the purity, NPDA is 97.5%, CNA
was 98.3%.

Example λ Example 1. Purified 2.4-DCNB was replaced with crude 2.4-
DCNB (93% purity, 2.6-D as other components)
Example 1. Ammonolysis was carried out at 160° C. for 4 hours in the same manner as above, and then treated in the same manner to obtain 50 g of a reaction product. When this product was analyzed by gas chromatography, it was found that CNA61.2
to, NPDA 33.7%, 2. 6-DCNB 2.9
- and other components were 2.2%. Put all of this in a beer bottle, add 50ON/15% hydrochloric acid, heat to 60°C, and react for 30 minutes.

Then Example 1. 17 g of NPDA and 32 g of CNA were obtained in the same manner as above. The CNA was then subjected to steam distillation with 700 d of water to remove 200 d of water. The amount of oil distilled out along with the distilled water was 2g, 72% of which was 2.
As a result, the yield (2,4,-
DCNB standard) NPDA is 35.8%, CNA
is 56.7%, and the purity is NPDA96.
．． 2%, CNA was 97.8%.

Patent applicant: Ishihara 1#, Gyo Co., Ltd.

Claims (1)

[Claims] 2. Reacting 4-dichloronitrobenzene with ammonium to form a mixture containing 5-chloro-2-nitroaniline and 4-nitro-m-phenylenediamine and applying mineral acid to the cough mixture. The mineral salt of 4-ditro-m-phenylenediamine is formed to form 5-chloro-2-
A method for producing 5-chloro-2-nitroaniline or 4-nitro-m-phenylenediamine, which comprises separating nitro-o7niline and 4-nitro-m-phenylenediamine.