Hydrogen Peroxide → HCID 178510672, compound

Participants

Reaction Conditions

Reaction Steps

3.0 liter of ethylene dichloride solvent & 421.0 gms of 5-amino-3-cyano-1-(2,6-dichloro-4-trifluromethylphenyl)-4-trifluromethylthio pyrazole was charged into a reactor flask with overhead stirring & condenser system. This mass was cooled to a temperature of about 5-10° C. and 1000.0 gms of H2SO4 (85.0% w/w) was added over a period of 1.5 to 2.0 hours. 61.0 gms of H2O2 (50.0% w/w) was then added to the aforesaid mass over a period of 3.0 hours at 07-13° C. The reaction temperature was maintained at a temperature of about 10-13° C. for about 1.0 hours. The reaction mass obtained thereafter was slowly added into 370 ml of chilled water at a 10-25° C. over a period of 2.0 hours. This mass was treated as in above experiments to yield crystalline fipronil (315.0 gms) of 95.0-96.5% purity.

Provenance & Evidence