Ammonia → 2,3,4-Trichlorophenylhydrazine

Temperature

60 °C

2,3,4-Trichloroaniline (100 g) was dissolved with stirring in glacial acetic acid (875 ml) at 55°-60° C. A solution of sodium nitrite (39.5 g) in concentrated sulphuric acid (300 ml) was then added over 15 minutes at 55°-60° C. to the solution thus obtained. The viscous mixture obtained was cooled to 5°-10° C. and a solution of stannous chloride dihydrate (437 g) in concentrated hydrochloric acid (375 ml) was added at 5°-10° C. over 20 minutes. A fine, off-white solid precipitated. To aid filtration, the mixture was warmed to 60° C., allowed to cool to laboratory temperature and then filtered. The precipitate was washed on the filter with saturated aqueous sodium chloride solution (100 ml). The damp powder thus obtained was added to a stirred mixture of aqueous ammonia (1.3 liters; S.G. 0.880) and ice. The fine slurry which formed was filtered and the precipitate obtained was dried at 80° C., and boiled twice with chloroform (2×1.5 liters). The chloroform extracts were combined and evaporated to dryness to give 2,3,4-trichlorophenylhydrazine (86 g), m.p. 142°-143° C., in the form of a colourless powder.

1. customthus obtained
2. customThe viscous mixture obtained
3. temperaturewas cooled to 5°-10° C.
4. customA fine, off-white solid precipitated
5. filtrationfiltration
6. temperatureto cool to laboratory temperature
7. filtrationfiltered
8. washThe precipitate was washed on the
9. filtrationfilter with saturated aqueous sodium chloride solution (100 ml)
10. customThe damp powder thus obtained
11. customThe fine slurry which formed
12. filtrationwas filtered
13. customthe precipitate obtained
14. customwas dried at 80° C.
15. customevaporated to dryness

ORD record

ord-b2e5edff889c4d52bcd62cfe70cba9fb

Source dataset

uspto-grants-1985_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04496390