Lignin-Derived Non-Heme Iron and Manganese Complexes: Catalysts for the On-Demand Production of Chlorine Dioxide in Water under Mild Conditions
Lignin-Derived Non-Heme Iron and Manganese Complexes: Catalysts for the On-Demand Production of Chlorine Dioxide in Water under Mild Conditions
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DOI：
10.1021/acs.inorgchem.0c02742
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发表时间：
2021-02-05
影响因子：
4.6
通讯作者：
Abu-Omar, Mahdi M.
中科院分区：
文献类型：
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作者：
Champ, Tayyebeh B.;Jang, Jun H.;Abu-Omar, Mahdi M.
以2-甲氧基-4-丙基苯酚（二氢丁香酚）和甘氨酸为原料，合成了一种木质素衍生配体双（2-羟基-3-甲氧基-5-丙基苄基甘氨酸）。制备了两种单核的DHEG铁锰配合物，并对其进行了表征，并用于水溶液中的二氧化氯氧化反应。过氧乙酸（PAA）在氧化还原反应中用作“绿色”氧化剂以引发高价Fe和Mn（IV）-OH中间体的形成。EPR研究证实了高价Mn-IV物种的形成。在pH4.0和25 ℃下，Fe和Mn配合物都能催化氧化，其双分子速率常数分别为32和144 M-1 s（-1）。Mn络合物被发现是更有效的氧化与周转频率为17小时（-1），并在随后的添加PAA保持活性。PAA/Mn-DHEG对ClO 2的降解速率为一级反应，且随pH的升高而显著增加。一个机制，占所有的意见。
A lignin-derived ligand, bis(2-hydroxy-3-methoxy-5-propylbenzypglycine (DHEG), was synthesized from 2-methoxy-4-propylphenol (dihydroeugenol (DHE)) and the amino acid glycine. Two mononuclear iron and manganese complexes of DHEG were prepared, characterized, and employed for the oxidation of chlorite to chlorine dioxide in aqueous solution. Peroxyacetic acid (PAA) was used as a "green" oxidant in the redox reactions to initiate the formation of high-valent Fe and Mn (IV)-OH intermediates. EPR studies verified the formation of a high-valent Mn-IV species. Both Fe and Mn complexes catalyzed chlorite oxidation with bimolecular rate constants of 32 and 144 M-1 s(-1), respectively, at pH 4.0 and 25 degrees C. The Mn complex was found to be more efficient for chlorite oxidation with a turnover frequency of 17 h(-1) and remained active during subsequent additions of PAA. The rate of ClO2 decomposition with PAA/Mn-DHEG was first order in PAA and increased significantly as pH increased. A mechanism that accounts for all observations is presented.