Process for the preparation of alkali metal or alkali earth metal salts of 2,4-dichlor-6-hydroxy-s-triazin

Production of alkali(ne earth) metal salts of 2,4-dichloro-6-hydroxy-s-triazine by hydrolysis comprises dosing cyanuric chloride (I) powder or aqueous suspension into an aqueous solution or suspension of 1.2-5 equivalent alkali(ne earth) hydroxide (II)/mole (I) and keeping the pH at 9.5-14 at ≤ 10 degrees C. Production of alkali(ne earth) metal salts of 2,4-dichloro-6-hydroxy-s-triazine by hydrolysis comprises dosing cyanuric chloride (I) powder or aqueous suspension into an aqueous solution or suspension of 1.2-5 equivalent alkali(ne earth) hydroxide (II)/mole (I) and keeping the pH at 9.5-14 at ≤ 10 degrees C. If less than the stoichiometric amount of (II) is present, the rest, including up to 25% excess, is added during and/or after addition of (I) to maintain the pH. Reaction is stopped when the pH no longer changes at the selected temperature.