Acetic Anhydride → Acetic acid N'-(2,4-dichloro-phenyl)-hydrazide

Participants

Reaction Conditions

Reaction Steps

A slurry of 101.4 grams (0.4751 mole) of 2,4-dichlorophenylhydrazine hydrochloride in 600 mL of water was stirred, and a solution of 20.9 grams (0.5225 mole) of sodium hydroxide in 100 mL of water was slowly added. During the addition, the reaction mixture thickened. An additional 50 mL of water was added to aid fluidity. Upon completion of addition of the sodium hydroxide solution, an additional 70 mL of water was added. The reaction mixture was stirred for about 75 minutes, then it was extracted with three 300 mL portions of ethyl acetate. The extracts were combined and dried with magnesium sulfate. The mixture was filtered and the filtrate containing free 2,4-dichlorophenylhydrazine (1) was transferred to an appropriate reaction vessel. The stirred solution was cooled to about 10° C., and 58.2 grams (0.5701 mole) acetic anhydride was added dropwise. Upon completion of addition, gas chromatographic (GC) analysis of the reaction mixture indicated the reaction was about 99% complete. The cooling medium was removed, and a solution of 62.5 grams of potassium carbonate in 200 mL of water was added to the reaction mixture. The mixture was stirred for about five minutes and the organic layer was separated. The organic layer was concentrated under reduced pressure, yielding 102.0 grams (98% yield) of 1-acetyl-2-(2,4-dichlorophenyl)hydrazine (2).

Provenance & Evidence