The Production Process of 4,5-Diaminopyrimidine

The production process of 4,5-diaminopyrimidine (4,5-DAP) is a critical step in the chemical industry, as this compound is widely used as a precursor for the synthesis of various chemicals, pharmaceuticals, and agrochemicals.
The production process involves several steps, including the synthesis of the starting materials, nitration, diazotization, coupling, and finally, sulfonation.

Synthesis of Starting Materials
The production of 4,5-DAP starts with the synthesis of the starting materials required for the process.
These starting materials include aniline and nitrobenzene.
Aniline is synthesized from benzene and nitrobenzene is synthesized from benzene and nitric acid.

Nitration
The next step in the production of 4,5-DAP is nitration.
In this step, aniline and nitrobenzene are reacted with nitric acid to form 2-nitroaniline and 2-nitro-4,5-diaminobenzene, respectively.
The reaction is carried out in the presence of a solvent, such as water or acetonitrile, to increase the solubility of the reactants and the reaction product.

Diazotization
In the next step, the nitro derivatives are diazotized using sodium nitrite and hydrochloric acid.
The reaction leads to the conversion of the nitro groups to azo groups, resulting in the formation of 2-azo-4,5-diaminobenzene and 2-azo-6-nitro-4,5-diaminobenzene.

Coupling
The next step in the production process is coupling.
In this step, the azo derivatives are heated with a mixture of alcohols, such as methanol or ethanol, in the presence of an acid catalyst, such as sulfuric acid or phosphoric acid.
The alcohols react with the azo groups to form new azo bonds, resulting in the formation of 4,5-diaminopyrimidine.

Sulfonation
Finally, the 4,5-diaminopyrimidine is sulfonated using sulfuric acid.
The sulfonation reaction introduces sulfonic acid groups into the molecule, which enhances the water solubility of the compound and makes it easier to recover and purify.

Purification and Recovery
After the sulfonation step, the 4,5-diaminopyrimidine is purified and recovered by precipitation with a solvent, such as water or ethanol, or by crystallization.
The purified product is then dried, and the sulfuric acid is removed by neutralization with a base, such as sodium hydroxide.

The production process of 4,5-diaminopyrimidine is a complex and multi-step process that requires careful control of the reaction conditions to ensure the purity and quality of the final product.
The production of this compound is an important part of the chemical industry and is critical for the synthesis of many important chemicals, pharmaceuticals, and agrochemicals.