| abstract |
Reacting, in a first step, an aqueous alkali metal salt solution of phthalic acid monoamide, optionally in admixture with phthalimide, under alkaline conditions with alkali metal hypochlorite, e.g., at a temperature of about -5* to +40* C., and adding all at once, in a second step, an amount of acid substantially equivalent to the alkali present in the solution to neutralize such alkali and form isatoic anhydride and thereby cause separation of the isatoic anhydride from the solution, said isatoic anhydride being a known intermediate for the preparation of plant protection agents and dyestuffs. |