Hydrochloric Acid → (4-Chlorophenyl)hydrazine

Temperature

50 °C

In a 2 l four-necked flask fitted with dropping funnel, stirrer and condenser, 95 g of HCl 30% strength and 57 g of n-butanol (saturated with water, approximately 80% strength) are initially charged. The solution is heated to 50° C. and, over a period of 2 hours, admixed with a total of 720 g of an aqueous solution of 4-chlorophenylhydrazinedisulfonate- prepared by diazotization of 34.4 g (0.27 mol) of 4-chloroaniline (100 g of water, 78 g of HCl 30% strength, 55 g of NaNO2) and subsequent reduction with sulfite (186 g of NaHSO3 +57 g of NaOH). The reaction emulsion is kept at 50° C. for another 60 minutes, the pH is adjusted to 6.9 using 119 g of aqueous sodium hydroxide solution 33% strength, and the aqueous phase that is formed is separated off. The aqueous phase is extracted three times with 5 ml of n-butanol each time, and the combined organic phases are cooled to 15° C. The 4-chlorophenylhydrazine that is formed is filtered off with suction at 15° C. as a crystalline solid, using a 500 ml suction filter, washed with 50 ml of n-butanol and dried.

1. customIn a 2 l four-necked flask fitted
2. customthe aqueous phase that is formed
3. customis separated off
4. extractionThe aqueous phase is extracted three times with 5 ml of n-butanol each time
5. temperaturethe combined organic phases are cooled to 15° C

ORD record

ord-d8829f9db29f4493a832664328b034c2

Source dataset

uspto-grants-2000_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06057478