Gaseous catalytic hydrogenation of nitrobenzene to aniline in a two-stage fluidized bed reactor

Gaseous hydrogenation of nitrobenzene over a Cu/SiO2 catalyst has been studied in a two-stage and in a single-stage fluidized bed reactor, at 513-553 K and atmospheric pressure. The placement of the second perforated plate in the fluidized bed reactor inhibits the backmixing of gases and solids and consequently increases the local molar ratio of hydrogen to nitrobenzene in the second stage. Thus, the conversion of nitrobenzene and the selectivity of aniline production and the stable life of the catalyst are significantly increased in the two-stage fluidized bed reactor, as compared with those in the single-stage one. A comparison of the coke formation and the burning characteristics of cokes in different reactors has also been presented. It suggests the simple catalyst regeneration for the two-stage fluidized bed technology. This work provides an effective method to produce aniline with higher purity. (c) 2005 Elsevier B.V. All rights reserved.