Hydrogen Peroxide → HCID 178510672, compound

Participants

Reaction Conditions

Reaction Steps

In a reactor flask with overhead stirring system, 2500 gms of 85.0% W/W H2SO4 & 100 ml of ethylene dichloride solvent was charged. This mass was cooled under stirring to 3.0-5.0° C. and then 421.0 gms of 5-amino-3-cyano-1-(2,6-dichloro-4-trifluromethylphenyl)-4-trifluromethylthio pyrazole solid was added over a period 1.0 hour. 95.0 gms of H2O2 (50.0% w/w) was then added to the aforesaid mass over a period of 3.0 hours at 3-8° C. The reaction temperature was maintained at a temperature of about 6-13° C. for about 3.0 hours. The reaction mass obtained thereafter was slowly added into 475-500 ml of chilled water at a 10-25° C. over a period of 2.0 hours. This mass was filtered/centifuged at 30-35° C. and the solid cake was washed with plenty of water to make it free of acidity. The crude cake wasdried and then crystallized in 1000 ml of dichloro ethane solvent to yield 360.0 gms of crystalline fipronil with 94.0-96.0% purity.

Provenance & Evidence