The Production Process of 4-CHLORO-5-HYDROXY-3(2H)-PYRIDAZINONE

4-Chloro-5-hydroxy-3(2H)-pyridazinone is an important intermediate in the production of various pharmaceuticals, agrochemicals, and other chemical products.
The production process of 4-chloro-5-hydroxy-3(2H)-pyridazinone involves several steps, including preparation of the starting materials, chemical reactions, and purification of the final product.

Preparation of Starting Materials

The production of 4-chloro-5-hydroxy-3(2H)-pyridazinone typically begins with the preparation of the starting materials, which include 3-nitrophenol and chloroform.
3-nitrophenol can be synthesized by the nitration of phenol with a mixture of nitric and sulfuric acids.
Chloroform can be synthesized by the chlorination of methane in the presence of a Lewis acid catalyst, such as aluminum chloride.

Chemical Reactions

The next step in the production of 4-chloro-5-hydroxy-3(2H)-pyridazinone is the reaction of 3-nitrophenol with sodium hydroxide to form 3-hydroxy-3-nitrophenol.
This reaction is typically carried out in the presence of a solvent, such as water or ethanol, and a catalyst, such as hydrochloric acid or sulfuric acid.

The 3-hydroxy-3-nitrophenol is then treated with chloroform in the presence of a solvent, such as ethanol, and a catalyst, such as zinc chloride or aluminum chloride.
This reaction is known as the "Borch reaction" and results in the formation of 4-chloro-5-hydroxy-3(2H)-pyridazinone.

Purification of the Final Product

The final step in the production of 4-chloro-5-hydroxy-3(2H)-pyridazinone is the purification of the final product.
This can be achieved by several methods, including crystallization, filtration, and chromatography.
Crystallization involves the formation of the final product as a crystalline solid, which can then be separated from the reaction mixture by filtration.
Chromatography involves the separation of the final product from other components in the reaction mixture by passing the mixture through a column packed with a solid adsorbent, such as silica gel or alumina.

Conclusion

The production of 4-chloro-5-hydroxy-3(2H)-pyridazinone is a multi-step process that requires the preparation of starting materials and the performance of several chemical reactions.
The final product can be purified by several methods, including crystallization, filtration, and chromatography.
The use of advanced technologies and the optimization of the production process can lead to increased efficiency and reduced costs.
The demand for 4-chloro-5-hydroxy-3(2H)-pyridazinone as an important intermediate in the production of pharmaceuticals, agrochemicals, and other chemical products is expected to continue to grow in the future.