preparation of 2-cyano-4-nitro-6-bromoaniline_kain industrial additive

background and overview^[1]

2-cyano-4-nitro-6-bromoaniline is a very important disperse dye intermediate and an important raw material for the synthesis of disperse dyes such as disperse blue 183.

preparation^[1]

(1) synthesis of 2-cyano-4-nitroaniline:

a1. put 100g o-chlorobenzonitrile into 333g sulfuric acid medium, then add mixed acid dropwise, and perform nitrification at 5-10°c to obtain nitrates; the mixed acid is hno₃ and h₂so₄ is mixed with a mass percentage of 0.5:1;

a2. add water to hydrolyze the nitrate in step a1, and then filter it to obtain the nitrification material;

a3. dissolve the nitration material in step a2 in 400g chlorobenzene to obtain a nitric chlorine mixture;

a4. carry out an ammonolysis reaction between the nitric chlorine mixture and liquid ammonia in step a3. after the reaction reaches the end point, distill and recover the solvent at 80°c; the ammonolysis reaction temperature is 110°c, and the ammonolysis reaction pressure is 2.6mpa; reaction the end point is measured in a liquid chromatograph;

a5. filter the solvent in step a4 and wash it with water until neutral to obtain a wet product, namely 2-cyano-4-nitroaniline wet product;

the reaction equation in step (1) is:

it can be seen that the sulfuric acid medium essentially acts as a solvent and provides acidic conditions for the reaction, and sulfuric acid does not participate in the reaction.

(2) synthesis of 2-cyano-4-nitro-6-bromoaniline:

b1. weigh 100g of 2-cyano-4-nitroaniline prepared in step a5 and put it into 20g of sulfuric acid medium, then dropwise add hydrogen bromide and 50g of hydrogen peroxide to react;

b2. after the reaction in step b1 reaches the endpoint through endpoint control, filter it to obtain the wet product of 2-cyano-4-nitro-6-bromoaniline.

the reaction equation in step (2) is:

similarly, the sulfuric acid medium essentially acts as a solvent, providing acidic conditions for the reaction to proceed, and sulfuric acid does not participate in the reaction.

references

[1] [chinese invention, chinese invention authorization] cn201410524535.9 a synthesis process of 2-cyano-4-nitro-6-bromoaniline