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用脉冲吸附和程序升温脱附(TPD)对α-Fe_2O_3,ZnFe_2O_4和ZnCrFeO_4进行了正丁烯异构体的吸附和反应性能的考察。结果表明,在室温下,三种正丁烯在α-Fe_2O_3上几乎不发生表面反应,而在ZnFe_2O_4,ZnCrFeO_4上则有不同程度的双键位移和选择氧化。多次脉冲吸附表明,第二次脉冲尾气中的丁二烯含量远大于第一次脉冲。各丁烯在三种氧化物上吸附后的TPD谱可分为以丁烯和丁二烯为脱附物的低温区(<200℃)与脱附物全部为CO_2的高温区(200～600℃)。丁烯-1在α-Fe_2O_3上较易热脱附,在其余两种氧化物表面上则强烈滞留,需经多次TPD才能脱净。还讨论了选择氧化部位和全氧化部位在这类氧化物表面上的可能形态。
Adsorption and reaction performance of n-butylene isomers of α-Fe 2 O 3, ZnFe 2 O 4 and ZnCrFeO 4 were investigated by pulse adsorption and temperature programmed desorption (TPD). The results showed that almost none of the three n-butenes reacted on α-Fe_2O_3 at room temperature, while the ZnFe_2O_4 and ZnCrFeO_4 had different degrees of double bond displacement and selective oxidation. Multiple pulse adsorption shows that the content of butadiene in the second impulse tail gas is much larger than the first one. The TPD spectrum of each butene adsorbed on three kinds of oxides can be divided into the low temperature region (<200 ℃) with desorption of butene and butadiene and the high temperature region (200-600 ℃). Butene-1 is more easily desorbed on α-Fe_2O_3 and strongly retained on the remaining two oxide surfaces, requiring multiple TPDs to be removed. The possible morphologies of selective and fully oxidized sites on the surface of such oxides are also discussed.