2-Fluorobenzaldehyde CAS 446-52-6

The current industrial synthesis methods of 2-fluorobenzaldehyde are as follows:

• Chlorinated hydrolysis of 2-fluorotoluene
  Among the chemical methods, the most traditional process for the synthesis of 2-fluorobenzaldehyde is 2-fluorotoluene chlorination and hydrolysis, which is to chlorinate the side chain of 2-fluorotoluene under the action of a catalyst to make 2-fluorodichloro Benzyl is then hydrolyzed under the action of a hydrolysis catalyst to generate 2-fluorobenzaldehyde. In the production of this method, due to the different chlorination depths, the results of chlorination are also different, and different degrees of by-products often appear during chlorination. In addition, most of the hydrolysis reactions are catalyzed by concentrated sulfuric acid, and the yield is only about 80%, and a large amount of waste acid is produced, which seriously pollutes the environment.
• 2-Toluidine synthesis method
  In the method, 2-toluidine is used as a raw material, and 2-fluorobenzaldehyde is prepared through Seaman reaction and chlorinated hydrolysis. Although this method is easy to obtain raw materials, the synthesis steps are numerous, and it still returns to the route of preparing 2-fluorobenzaldehyde by chlorination of 2-fluorotoluene, so that the scope of use of 2-fluorobenzaldehyde is greatly reduced, and it is not suitable for large-scale of industrial production.
• 2-Fluorobenzaldehyde is prepared by continuous oxidation of 2-fluorotoluene in a tubular reactor with a specific structure
  Using 2-fluorotoluene as raw material, photocatalytic chlorination generates 2-fluorodichlorotoluene, which is then hydrolyzed to prepare 2-fluorobenzaldehyde.

The above methods have the following problems: firstly, large-scale chlorination reduces the scope of use of 2-fluorobenzaldehyde, which cannot be used in some high-end industries; secondly, large-scale hydrolysis needs to consume a large amount of catalyst and generate a large amount of waste. Acid and waste water cause serious pollution to the environment; finally, the tedious process steps greatly increase the production cost; chlorine gas, which is highly toxic and strictly controlled by the state, is used, and the diazotization reaction and photochlorination reaction restricted by the state are used.