Stepanov Alexander G, Arzumanov Sergei S, Gabrienko Anton A, Parmon Valentin N, Ivanova Irina I, Freude Dieter
Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk 630090, Russia.
Chemphyschem. 2008 Dec 1;9(17):2559-63. doi: 10.1002/cphc.200800569.
Herein, we analyze earlier obtained and new data about peculiarities of the H/D hydrogen exchange of small C(1)-n-C(4) alkanes on Zn-modified high-silica zeolites ZSM-5 and BEA in comparison with the exchange for corresponding purely acidic forms of these zeolites. This allows us to identify an evident promoting effect of Zn on the activation of C-H bonds of alkanes by zeolite Brønsted sites. The effect of Zn is demonstrated by observing the regioselectivity of the H/D exchange for propane and n-butane as well as by the increase in the rate and a decrease in the apparent activation energy of the exchange for all C(1)-n-C(4) alkanes upon modification of zeolites with Zn. The influence of Zn on alkane activation has been rationalized by dissociative adsorption of alkanes on Zn oxide species inside zeolite pores, which precedes the interaction of alkane with Brønsted acid sites.
在此，我们分析了早期获得的以及新的数据，这些数据涉及在锌改性的高硅沸石ZSM - 5和BEA上，C(1)-正-C(4)小烷烃的H/D氢交换特性，并与这些沸石相应纯酸性形式的交换情况进行了比较。这使我们能够确定锌对沸石布朗斯特酸位点活化烷烃C - H键具有明显的促进作用。通过观察丙烷和正丁烷H/D交换的区域选择性，以及在用锌改性沸石后，所有C(1)-正-C(4)烷烃交换速率的增加和表观活化能的降低，证明了锌的作用。锌对烷烃活化的影响已通过烷烃在沸石孔内氧化锌物种上的解离吸附得到合理解释，这种吸附先于烷烃与布朗斯特酸位点的相互作用。
