Patent ID: 6852890

Claim:
A process for the preparation of a phenylhydrazine or an inorganic acid salt thereof of the formula (1): wherein X is a hydrogen atom or a halogen atom; Y is a halogen atom; and W is a hydrogen atom or —ZR in which Z is an oxygen atom or a sulfur atom, and R is a hydrogen atom, a C 1 -C 6 alkyl group, a C 1 -C 6 haloalkyl group, a C 3 -C 6 cycloalkyl group, a benzyl group, a C 3 -C 6 alkenyl group, a C 3 -C 6 haloalkenyl group, a C 3 -C 6 alkynyl group, a cyano-C 1 -C 6 alkyl group, a C 2 -C 8 alkoxyalkyl group, a C 2 -C 8 alkylthioalkyl group, a carboxy-C 1 -C 6 alkyl group, (C 1 -C 8 alkoxy) carbonyl-C 1 -C 6 alkyl group, a [(C 1 -C 4 alkoxy)-C 1 -C 4 alkoxy]carbonyl-C 1 -C 6 alkyl group, (C 3 -C 8 cycloalkoxy) carbonyl-C 1 -C 6 alkyl group or a [(C 1 -C 6 alkoxy)carbonyl-C 1 -C 6 alkyl]oxycarbonyl-C 1 -C 6 alkyl group; said method consisting essentially of the step of hydrolyzing a phenylhydrazine derivative of the formula (2): in the presence of water and an inorganic acid, wherein the concentration of the inorganic acid is at least 6 moles per 1 kg of water in a reaction system; wherein X, Y and W of formula (2) are the same as defined in formula (1), and the Q groups are the same or different from each other and represent a hydrogen atom, an ammonium group or an alkali metal atom.