Molecular Design,synthesis,and Properties Research Of The Practical Fe-TAMLs

Iron-tetraamino macrocyclic ligand complex(Fe-TAML)is an organic metal catalyst which can catalyze the decomposition of hydrogen peroxide efficiently.It has attracted more and more attention in the fields of biochemical wastewater treatment and dye decolorization due to its low dosage,high treatment efficiency and self-degradability.In this paper,a brand new synthesis route of the second generation of Fe-TAML is redesigned and optimized,which reduces the cost of synthesis and makes it conducive to industrial production.Replacing o-phenylenediamine with o-nitroaniline as reactant,amide intermediate was obtained by reacting with 2,2-dimethylmalonyl dichloride,then nitro was reduced to amino group,and finally the intermediate containing two amino groups reacted with another acyl chloride to obtain cyclic amide compound.The final product Fe-TAMLs was obtained by complexing the cyclic ligand with iron salts under the action of alkali.Compared with the original synthesis method,the new method reduced from five steps to four steps,and the yield increased from 30.1%to 49.5%,which further reduced the cost of synthesis.Three kinds of Fe-TAML catalysts with different structures were synthesized,and the conditions for their catalytic degradation of simulated dye wastewater were explored.By controlling the reaction time,temperature,pH,catalyst dosage and hydrogen peroxide dosage,the optimum reaction conditions of different catalysts were selected.The decolorization and chemical oxygen demand were measured to evaluate the degradation process.The optimum reaction temperature for this kind of reaction is 30?.The catalyst dosage range is 5-50 mg/L,and the hydrogen peroxide dosage range is 0.3-1.5 g/L.The catalytic effect is better in this range.Three kinds of catalysts were compared,and the effects of substituents such as methyl and nitro groups on the catalytic activity were explored,which provided a reference for the further design of the new catalyst structure.The decolorization of different dye molecules under the same reaction conditions was also compared,and the reaction conditions of catalysts in organic solvents with certain concentration were explored.