Oxidative dehydrogenation of cyclohexane and cyclohexene over supported gold, palladium and gold-palladium catalysts
Oxidative dehydrogenation of cyclohexane and cyclohexene over supported gold, palladium and gold-palladium catalysts
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DOI：
10.1016/j.cattod.2010.03.031
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发表时间：
2010-09-01
期刊：
影响因子：
5.3
通讯作者：
Hutchings, Graham J.
中科院分区：
文献类型：
--
作者：
Dummer, Nicholas F.;Bawaked, Salem;Hutchings, Graham J.
负载型金、钯和金-钯催化剂已被用于环己烷和环己烯的氧化还原。负载型金属纳米颗粒降低了脱氢反应的活化温度。我们发现反应性的顺序是Pd >= Au-Pd >负载在TiO 2上的Au。尝试降低反应温度同时保持高选择性。在473 K时，环己烷催化苯生成苯的时空产率为53.7 mol/kg（cat）/h，在673 K时上升到87.3 mol/kg（cat）/h。在这种情况下，提高温度改善了转化率，但损害了苯的选择性。在AuPd/TiO_2或Pd/TiO_2催化剂上，环己烯氧化脱氢反应非常有效（423 K时转化率>99%）。这些结果表明，在环己烷到环己烯的反应序列中的第一步是最慢的步骤。这些初步结果表明，在固定床反应器中，在氧、钯和金-钯催化剂存在下的氧化脱氢能够容易地超过目前的文献实例，并且通过进一步的改进应该产生甚至更高的性能。(C)2010 Elsevier B. V.保留所有权利。
Supported gold, palladium and gold-palladium catalysts have been used to oxidatively dehydrogenate cyclohexane and cyclohexenes to their aromatic counterpart. The supported metal nanoparticles decreased the activation temperature of the dehydrogenation reaction. We found that the order of reactivity was Pd >= Au-Pd > Au supported on TiO2. Attempts were made to lower the reaction temperature whilst retaining high selectivity. The space-time yield of benzene from cyclohexane at 473 K was determined to be 53.7 mol/kg(cat)/h rising to 87.3 mol/kg(cat)/h at 673 K for the Pd catalyst. Increasing the temperature in this case improved conversion at a detriment to the benzene selectivity. Oxidative dehydrogenation of cyclohexene over AuPd/TiO2 or Pd/TiO2 catalysts was found to be very effective (conversion >99% at 423 K). These results indicate that the first step in the reaction sequence of cyclohexane to cyclohexene is the slowest step. These initial results suggest that in a fixed-bed reactor the oxidative dehydrogenation in the presence of oxygen, palladium and gold-palladium catalysts are readily able to surpass current literature examples and with further modification should yield even higher performance. (C) 2010 Elsevier B.V. All rights reserved.