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用热重法(TG),微商热重法(DTG)和差示热分析(DTA)研究了α-氧化铁、铁酸锌和铁酸镁在丁烯-氧气氛下,400—540℃间的还原-氧化活性。它们在丁烯中的易还原性呈以下递降顺序:α-氧化铁>铁酸锌>铁酸镁。α-氧化铁易发生体相还原生成较低价化合物(Fe_3O_4);铁酸锌和铁酸镁只经历表面还原,脱除约两单层氧。在450℃,铁酸锌的还原速率2.17％/min,氧化速率1.29％/min。当有α-氧化铁相存在,还原速率降低到1.75％/min,氧化速率提高到2.20％/min。认为,加入α-氧化铁量占整个催化剂量的30—50％,对改进铁酸锌催化剂的稳定性有利。
The effects of α-iron oxide, zinc ferrite and magnesium ferrite in a butene-oxygen atmosphere at 400-540 ℃ were investigated by TG, DTG and DTA. Reduction between - oxidation activity. Their reducibility in butene decreases in the following order: α-iron oxide> zinc ferrite> magnesium ferrite. The α-iron oxide is prone to undergo phase reduction to produce lower-valent compounds (Fe 3 O 4); zinc ferrite and magnesium ferrite undergo only surface reduction to remove about two monolayers of oxygen. At 450 ℃, the reduction rate of zinc ferrite was 2.17% / min and the oxidation rate was 1.29% / min. When alpha-iron oxide is present, the reduction rate is reduced to 1.75% / min and the oxidation rate is increased to 2.20% / min. It is considered that adding α-iron oxide accounts for 30-50% of the total amount of the catalyst, which is beneficial to improving the stability of the zinc ferrite catalyst.