(8e) Kinetic Study of Catalytic Hydrogenation of Aromatic Nitro Compound in a Microchannel Reactor

Hydrogenation reactions are ubiquitous in the fine chemicals and pharmaceutical industries. The kinetics of fast three-phase hydrogenation reactions in conventional slurry or batch reactors is often limited by mass transfer of hydrogen gas through the liquid due to the limited solubility of hydrogen in organic substrates and solvents. The use of a microchannel reactor for such reactions provides improved mass transfer rates which may ensure that the reaction operates close to intrinsic kinetics. In the present study, hydrogenation of aromatic nitro compound was conducted in a packed-bed microreactor as a model hydrogenation reaction of importance to the pharmaceutical industry with the aim of investigating the kinetics of the reaction. Internal and external mass and heat transfer limitations were examined. Kinetic experiments were conducted in a differential reactor mode keeping the conversion of the reactant at less than 10%. Different rate laws using different mechanisms from the literature were considered to fit the experimental data. Experiments were also carried out in an integral reactor, and the integral reactor data were compared with the predictions of the theoretical models.