Hydrochloric Acid → 3-(Trifluoromethyl)pyrazole

2.71 kg of 1,1,1-trifluoro-4-methoxy-but-3-en-2-on, 2.44 kg of ethanol and 3.10 kg of water were charged into a reaction vessel. 20 ml of concentrated hydrochloric acid and 0.80 kg of hydrazine hydrate were successively added and the mixture was heated to reflux for 4 h. The mixtures was allowed to cool and neutralized by addition of 10% aqueous NaOH to about pH 4-5. Then the mixture was evaporated. Toluene was added and the mixture was again evaporated to yield 2 kg of raw 3-trifluoromethylpyrazole with a purity of >85%.

1. temperaturethe mixture was heated
2. temperatureto reflux for 4 h
3. temperatureto cool
4. customThen the mixture was evaporated
5. additionToluene was added
6. customthe mixture was again evaporated

ORD record

ord-4cc1f4e1a6124ddda915f48f3ba7efdc

Source dataset

uspto-grants-2014_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08921567B2