NIT-Ph-p-BEN氮氧自由基的制备及催化降解性

以对醛基苯甲酸为原料，通过醛酸与2,3-二甲基-2,3-二羟胺基丁烷缩合，再经NaIO4氧化最终制得4-(4,4,5,5-四甲基-1,3-二氧化物)咪唑基-1-苯甲酸（NIT-Ph-p-BEN氮氧自由基）。采用FTIR、UV、ERP（电子顺磁共振波谱仪）和元素分析等对其结构进行表征；通过催化降解废水中有机染料甲基橙、甲基蓝和罗丹明B对其催化活性进行了评估。结果表明，当甲基橙、甲基蓝和罗丹明B浓度为15 mg/L，NIT-Ph-p-BEN质量浓度为0.15 g/L，H2O2浓度为30 mmol/L时，NIT-Ph-p-BEN对甲基橙有更好的催化降解性，仅在1 h内甲基橙的降解率达到94.26%。此外，反应机理表明，H2O2有助于实现NIT-Ph-p-BEN自由基的再生和循环利用。

Degradability and activity of reactive nitroxide radicals NIT-Ph-p-BEN in catalytic oxidation of dyes

4-(4,4,5,5-tetramethyl-1,3-dioxide) imidazolyl-1-benzoic acid (NIT-Ph-p-BEN nitroxide radicals) was synthesized by a facile condensation reaction using 4-formylbenzoic acid and 2,3-bis(hydroxylamino)-2,3-dimethylbutane as precursors, and NaIO4 as oxidant. The product was characterized by FT-IR, UV, ERP and elemental analysis. The oxidative degradation activity of the NIT-Ph-p-BEN nitroxide radicals was investigated by catalytic degradation of organic dyes methyl orange, methyl blue and rhodamine B in wastewater. The results show that when the concentration of methyl orange, methyl blue and rhodamine B was 15 mg/L, and the concentration of NIT-Ph-p-BEN and H2O2 were 0.15 g/L and 30 mmol/L, respectively, NIT-Ph-p-BEN exhibited the best degradation activity for methyl orange. The degradation rate of methyl orange reached 94.26% only within 1 h. The catalytic mechanism demonstrated that NIT-Ph-p-BEN nitroxide radicals were effectively activated and regenerated by H2O2.