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考察了含碱金属离子和镍离子的X型沸石上乙烯的双聚反应。发现催化剂的活性有如下规律:LiNiX>NaNiX>KNiX。TPD考察表明催化剂的酸性亦有同样的规律。在LiNiX和NaNiX上乙烯的双聚反应出现诱导期,而在KNiX上则不出现。碱金属离子对镍离子有两方面的促进作用:一是调变催化剂的酸碱性,亦即调变活性中心Ni~+离子上的电子密度;二是调变活性中心Ni~+离子在沸石中的位置占据情况,亦即调变Ni~+离子的有效浓度。
The dimerization of ethylene on zeolite X containing alkali metal ions and nickel ions was investigated. The activity of the catalyst was found to have the following laws: LiNiX> NaNiX> KNiX. TPD study showed that the catalyst has the same acidity. Induction of dimerization of ethylene over LiNiX and NaNiX did not occur on KNiX. Alkali metal ions promote the nickel ions in two ways: one is to adjust the acid-base of the catalyst, that is to say, to change the electron density on the Ni ~ + ion of the active site; secondly, to modify the Ni ~ + ions in the zeolite In the position to occupy the situation, that is, tune the effective concentration of Ni ~ + ions.