Synthesis of novel acyclic and multiple phenyl iron tetraamino ligand catalysts and its catalytic activity for degradation of dye wastewater by H2O2

We need a practical, inexpensive, and green way to reduce the environmental pollutants, especially for dye wastewater. The discharge of industrial wastewater such as organic dyes will cause serious pollution to water bodies, thereby affecting people's lives. In this work, we designed and successfully synthesized four new ligand catalysts. The total outputs of diamide diamino iron ligand compounds A and B are 71.33% and 61.39%, respectively. The total outputs of polyaromatic iron tetraamido macrocyclic ligand (TAML) compounds C and D are 38.49% and 49.11%, respectively. The catalytic effects of four catalysts on the degradation of dye wastewater by hydrogen peroxide oxidation were studied and compared with the second‐generation FeIII‐TAML catalyst. The experimental results showed that acyclic catalyst A and B has good catalytic effect. For methylene blue, methyl orange, rhodamine B three dyes wastewater, under the conditions of 20°C, Ccatalyst A = 0.056–0.28 mM and Chydrogen peroxide = 33 mM, the decolorization rate and chemical oxygen demand (COD) removal rate are 81.53%–97.58% and 52.2%–60.7%, respectively. Under the condition of 20°C, Ccatalyst B = 0.75 mM and Chydrogen peroxide = 33 mM, the decolorization rate and COD removal rate are 48.33%–80.33% and 44.6%–57.8%, respectively. Several new complexes were designed and synthesized for catalytic degradation of dyes by hydrogen peroxide. The total yield of compound A and B was above 60%. The synthesis conditions were simple and the synthesis route was short. Compared with FeIII‐TAML catalyst, catalyst A and catalyst B have good catalytic effect and can replace FeIII‐TAML catalyst to realize large‐scale production and application.