期刊
APPLIED CATALYSIS A-GENERAL
卷 334, 期 1-2, 页码 199-206出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.apcata.2007.10.007
关键词
selective hydrogenation; p-chloronitrobenzene; p-chloroaniline; carbon and oxide supported Ni
We have established for the first time 100% selectivity in the continuous gas phase hydrogenation of p-chloronitrobenzene (p-CNB) to p-chloroaniline for reaction over a series of oxide and carbon supported Ni catalysts (6 +/- 2%, w/w) under mild reaction conditions (T= 393 K, P = 1 atm). Catalyst activation by temperature programmed reduction (TPR) is addressed, BET area and H-2 uptake measurements provided and mean metal particle sizes evaluated by transmission electron micrographic (TEM) analysis. The following activity sequence has been determined: Ni/Al2O3 > Ni/SiO2 > Ni/Activated Carbon > Ni/graphite. Pd/Al2O3, as an alternative catalyst, delivered an appreciably higher activity but with the production of nitrobenzene (principal product) and aniline (secondary product), i.e. hydrodechlorination with subsequent -NO2 reduction prevailed. Exclusive formation of the corresponding haloaniline is also demonstrated for the hydrogenation of o-chloronitrobenzene, m-chloronitrobenzene and p-bromonitrobenzene over Ni/Al2O3. A lower hydrogenation rate is established for p-CNB relative to nitrobenzene, consistent with a halogen substituent deactivation effect. While the Ni catalysts suffered a loss of activity with time-on-strearn, exclusive selectivity to the haloamine product was maintained. These preliminary results can serve as a basis for the development of a cleaner, high throughput production of commercially important haloamines. (c) 2007 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据