Green Synthesis Of 2-(2'-Hydroxy-5'-Methylphenyl) Benzotriazole

With the rapid development of world and the deterioration of the environment pollution,traditional chemical industry must go through the upgrade of enterprises.Hence,it is important to establish the cleaner production technology of chemical products.However,traditional production of benzotriazoles has caused serious environmental pollution.Based on this background,the synthesis of2-?2'-Hydroxy-5'-methylphenyl?benzotriazole?BTA?by catalytic hydrogenation was chosen as a template reaction and investigated,thus several green synthetic routes of benzotriazoles were successfully established in this paper.Firstly,the progress of benzotriazole ultraviolet absorber and hydrogenation catalyst was reviewed and discussed.Two Pd/?-Al₂O₃ catalysts were prepared by different methods and characterized.The characterization results demonstrated that the dispersion of Pd nanoparticles and the specific surface area of the catalyst were dramatically affected by the catalyst preparation process.The template reaction selectivity is depended on the distribution of Pd nanoparticles.Thus,a green continuous synthetic technology of BTA from NAB was successfully established through the optimization of the reaction parameters.Under the optimized conditions,about 90%yield of BTA was obtained.The catalyst could run over 200 h without obvious deactivation.To avoid the heavy use of additional base,a series of solid base-hydrogenation bifunctional catalysts were prepared by the modification of Pd/?-Al₂O₃ with potassium salts.Their characterization results indicated that basic sites were dispersed around hydrogenated active sites,and different potassium salts could have different impacts on their catalytic performance.In which case,KNO₃ exhibited the best modifying effect,the selectivity of BTA was up to 84.79%.Thus,BTA was successfully synthesized over the solid base-hydrogenation bifunctional catalyst without any base.Afterwards,magnetic 3D nitrogen doped graphene gels?MNG?were easily obtained via one-pot hydrothermal synthetic process.The characterization results manifested that the in situ formation of Fe₃O₄ nanoparticles could significantly alter the N doping mode without changing the N doping amount in graphene layers.Compared with traditional approaches,this method is more controllable and milder.The structure-activity relationship of MNG catalysts were investigated by the reduction of 4-nitrophenol to 4-aminophenol.It was found that the reaction no longer simply followed the pseudo-zero-order kinetics,this might be attributed to the enhancement of catalytic activity.Moreover,MNG catalysts were applied in the synthesis of BTA and a good result was achieved.