Preparation of fluorophenylhydrazines and salts thereof

Process for preparing fluorophenylhydrazines or salts thereof comprising the steps of:

• 1) diazotizing fluoroanilines in the presence of hydrochloric acid using a molar ratio of fluoroaniline to hydrochloric acid of 1:(2 to 2.9),
• 2) reducing in the presence of bisulphite liquor by adding alkali metal hydroxide solution at a pH in the range from 5 to 8 to form 2-fluorophenylhydrazine α,β-disulphonate,
• 3) hydrolysing the 2-fluorophenylhydrazine α,β-disulphonate using mineral acids in an aqueous medium which is free of organic solvents and
• 4) optionally adding alkali metal hydroxide solution to neutralize.