PRODUCTION OF BENZOTRIAZOLES

PURPOSE:To obtain the titled compound useful as a rust and corrosion preventing agent and a stabilizer for synthetic polymers in high purity and in high yield, by reacting a dihydroxybenzotriazole or a salt thereof with a catalytic amount of lead or a lead compound in the presence of a metal having a higher ionization tendency than that of lead in an acidic medium. CONSTITUTION:A hydroxybenzotriazole shown by formula I (R1-R4 are H, halogen or atom. or group selected from group stable to reaction in reaction medium) or a salt thereof is reacted with lead in an acid medium (especially preferably mineral acid or acidic salt thereof, organic carboxylic acid, organic sulfonic acid or acid anhydride thereof) or with lead or a lead compound in the presence of a metal (especially preferably aluminum) having a higher ionization tendency than that of lead in the acid medium to give a benzotriazole shown by formula II. The amounts of the metal and the acidic medium required are small, the reaction condition is mild and the raw materials are readily obtainable.