▎ 摘　　要

NOVELTY - Preparing benzotriazole ultraviolet absorbing agent involves reacting azo derivative (I) and alkali, dissolving in solvent, adding raw material solution into reaction device, adding ferric oxide/graphene catalyst to the raw material liquid, introducing hydrogen, keeping the pressure 0.1-5 megapascal. The temperature is 40-120 degrees C. The reaction mixture is cooled to restore normal pressure and post-treatment is carried out to obtain benzotriazole ultraviolet absorbing agent (II). USE - Method for preparing benzotriazole ultraviolet absorbing agent. ADVANTAGE - The method enables to prepare benzotriazole ultraviolet absorbing agent that is suitable for industrial production and convenient to recycle, has low cost, mild reaction condition, stable property, high yield and quality of the product, and in simple, eco-friendly and cost effective manner. DETAILED DESCRIPTION - Preparing benzotriazole ultraviolet absorbing agent involves reacting azo derivative of formula (I) and alkali, dissolving in solvent, adding raw material solution into reaction device, adding ferric oxide/graphene catalyst to the raw material liquid, introducing hydrogen, keeping the pressure 0.1-5 megapascal. The temperature is 40-120 degrees C. The reaction mixture is cooled to restore normal pressure and post-treatment is carried out to obtain benzotriazole ultraviolet absorbing agent of formula (II). R=Hydrogen or chlorine, formula (III); R1=Hydrogen, 1-5C alkyl; R2=1-12C alkyl, formula (III) and formula (IV); R3-R4=Hydrogen, 1-3C alkyl; and m=0-5.