Ammonia → Chloridazon

Participants

Reaction Conditions

Reaction Steps

85 parts by volume of 15% (wt %) strength aqueous ammonia, 12.05 parts by weight of 4,5-dichloro-1-phenylpyridaz-6-one and 6.2 parts by weight of a 70% strength aqueous solution of phenol-4-sulfonic acid (parts by volume bearing the same relationship to parts by weight as the liter to the kilogram) are introduced into a jacketed pressure vessel having a capacity of 300 parts by volume. The reaction mixture is heated to 130° C. while stirring and kept for 4 hours at this temperature, while still stirring. The autogenous pressure which is hereupon generated is 6 bars. The reaction mixture is then allowed to cool to room temperature (20° C.) and the mother liquor is completely filtered off. The solid reaction product is washed with water and dried in vacuo at 100° C. There is obtained 9.8 parts by weight (89% of theory) of 4-amino-5-chloro-1-phenylpyridaz-6-one of melting point 205°-206° C. The amount of 5-amino-4-chloro-1-phenylpyridaz-6-one is determined gas-chromatographically and found to be 1%, and the amount of 4-amino derivative 99%.

Provenance & Evidence