HYDROGENOLYSIS OF PROPANE, NORMAL-BUTANE, AND ISOBUTANE OVER VARIOUSLY PRETREATED RU/TIO2 CATALYSTS
HYDROGENOLYSIS OF PROPANE, NORMAL-BUTANE, AND ISOBUTANE OVER VARIOUSLY PRETREATED RU/TIO2 CATALYSTS
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DOI：
10.1021/j100411a032
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发表时间：
1986-09-25
影响因子：
--
通讯作者：
BURCH, R
中科院分区：
文献类型：
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作者：
BOND, GC;RAJARAM, RR;BURCH, R
用不同方法预处理的Ru/TiO_2催化剂（含0.5wt%和5wt% Ru）研究了丙烷、正丁烷和异丁烷的氢解反应。在758 K下通过H2还原RuCl 3/Ti 〇 2得到低至中等活性的催化剂;它们被认为基本上被Cl-污染并且不处于低活性SMSI状态，然而在893 K下还原时获得低活性SMSI状态。在任一温度下第一次还原后在623 K下氧化，随后温和还原，得到高活性、不含Cl-且处于非SMSI状态的催化剂。该处理导致高度分散的Ru颗粒，其表现出高的甲烷选择性;使用Kempling-Anderson形式主义的产物分布的分析显示，在正丁烷的情况下，氧化的催化剂对末端CC键断裂具有明显的偏好。高温下的还原导致催化剂在SMSI状态下的低活性，但在758 K还原后的剩余活性是由于没有屈服于SMSI的小颗粒，而在893 K还原后则是由于第一次还原后的大颗粒。异丁烷的反应活性比正烷烃低得多，可能是因为它需要一个更大的活性中心来进行化学吸附。
The hydrogenolysis of propane, n-butane, and isobutane has been investigated using Ru/Ti02 catalysts containing 0.5 and5 wt% Ru pretreated in various ways. Reduction of RuCl3/Ti02 by H2 at 758 K gives catalysts of low to moderate activity; they are thought to be substantially contaminated by Cl" and not in the low-activity SMSI state, which is however attained on reduction at 893 K. Oxidation at 623 K after the first reduction at either temperature, followed by mild reduction, affords catalysts of high activity, free of Cl", and in a non-SMSI state. This treatment leads to highly dispersed Ru particles, which exhibit high methane selectivities; analysis of product distributions using the Kempling-Anderson formalism shows in the case of Ŧ-butane that oxidized catalysts have a marked preference for terminal CC bond breaking. Subsequent reductions at hightemperature lead to catalysts of low activity in the SMSI state, but residual activity after 758 K reduction is due to small particles which havenot succumbed to SMSI and after 893 K reduction to large particles persisting from the first reduction. Isobutane is much less reactive than the Ŧ-alkanes, perhaps because it requires a larger active center for its chemisorption.