Ring-Opening Hydrogenation Reactions of Monoalkyl Substituted Cyclobutanes over Ni/SiO2 Catalyst
Ring-Opening Hydrogenation Reactions of Monoalkyl Substituted Cyclobutanes over Ni/SiO2 Catalyst
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DOI：
10.1006/jcat.1995.1033
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发表时间：
1995-02
影响因子：
7.3
通讯作者：
B. Torok;M. Bartók
中科院分区：
文献类型：
--
作者：
B. Torok;M. Bartók
研究了在宽温度和氢气压力范围内，在 Ni/SiO{sub 2} 催化剂上甲基环丁烷和丙基环丁烷的加氢开环反应。首先，确定了开环的温度依赖性，并观察了两种反应物的最大曲线。根据温度依赖曲线，选择不同的温度进行氢气压力研究。在 523 和 573 K 下，仅发生氢化开环，并且在甲基环丁烷在清洁且工作的催化剂上的情况下，环主要在空间位阻较小的方向上开环。然而，对于丙基环丁烷，选择性接近统计或与甲基环丁烷相反，特别是在初始催化剂的氢气压力较低的情况下。在开环发生的最低温度下，观察到专有的庚烷形成（在更受阻碍的方向上开环）。初始催化剂和工作催化剂的氢压力依赖曲线用于得出有关开环反应的机理推论。 25 条参考文献、5 张图、2 个标签。
The hydrogenative ring-opening reactions of methyl- and propylcyclobutane were studied over Ni/SiO{sub 2} catalyst in wide temperature and hydrogen pressure ranges. Firstly, the temperature dependence of ring opening was determined and maximum curves were observed for both reactants. On the basis of the temperature dependence curves, various temperatures were selected for hydrogen pressure studies. At both 523 and 573 K, only hydrogenative ring opening occurred, and the ring opened mostly in the sterically less hindered direction in the case of methylcyclobutane over clean as well as working catalysts. However, for propylcyclobutane the selectivity was close to statistical or opposite to that for methylcyclobutane, especially at lower hydrogen pressures over the initial catalyst. At the lowest temperature at which ring opening occurred at all, exclusive heptane formation (ring opening in the more hindered direction) was observed. The hydrogen pressure dependence curves over the initial and working catalysts were used to draw mechanistic inferences concerning the ring-opening reactions. 25 refs., 5 figs., 2 tabs.