Activity and mechanism of the catalytic action of rare-earth oxides in low-temperature ethylene hydrogenation
Activity and mechanism of the catalytic action of rare-earth oxides in low-temperature ethylene hydrogenation
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稀土氧化物低温乙烯加氢催化活性及机理
DOI：
10.1016/0021-9517(77)90256-1
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发表时间：
1977
影响因子：
7.3
通讯作者：
V. S. Nakhshunov
中科院分区：
文献类型：
--
作者：
K. Minachev;Y. Khodakov;V. S. Nakhshunov
研究了稀土氧化物及其类似物氧化钪和氧化钇在-120 ~20 °C乙烯加氢反应中催化活性随预处理温度的变化。热分析已被用来研究的分解的氢氧化物从其中制备的氧化物。氧化物在600 °C下预处理后显示出催化活性，此时脱水、脱羧和脱氮已经完成，此外，当表面的部分脱羟基也发生时。倍半氧化物表现出高活性，而二氧化物活性较低。从氧化镧到氧化镥的一系列氧化物的氢化活性的降低与它们的碱度的降低相关。如通过热解吸所示，氢和乙烯以两种形式化学吸附。对于dysprosia，已经表明，通过使用氘代物质，乙烯氢化通过经由半氢化络合物涉及氢和乙烯的松散结合形式来进行。缔合吸附的乙烯参与反应，氢活化可能是限制步骤。
The variation in catalytic activity of rare-earth oxides and their analogs, scandia and yttria, in ethylene hydrogenation between −120 and 20 °C has been studied as a function of the temperature of pretreatment. Thermal analysis has been used to study the decomposition of the hydroxides from which the oxides were prepared. The oxides show catalytic activity after pretreatment at 600 °C when dehydration, decarboxylation, and denitroxylation have gone to completion and, in addition, when partial dehydroxylation of the surface has also taken place. Sesquioxides showed high activity, whereas dioxides were of low activity. A decrease in hydrogenating activity in the series of oxides from lanthana to lutecia correlates with a decrease in their basicity. As was shown by means of thermodesorption, hydrogen and ethylene are chemisorbed in two forms. With dysprosia, it has been shown, by using deuterated species, that ethylene hydrogenation proceeds by involving loosely bound forms of hydrogen and ethylene via a semihydrogenated complex. Associatively adsorbed ethylene is involved in the reaction, and hydrogen activation is likely to be the limiting step.