Resin-Based Spherical Activated Carbon-Supported Pt-Pd Catalysts for Continuous Liquid-Phase Hydrogenation of Nitrobenzene

Liquid-phase hydrogenation of nitrobenzene (NB) to aniline (ANL) is an important industrial route. However, continuous packed-bed operation is often hindered by local overheating, catalyst sintering, and particle attrition. In this work, mechanically robust resin-based spherical activated carbon beads (RSAC) were used as reactor-compatible supports. Pd/C, Pt/C, and Pt-Pd/C catalysts were prepared on this support. The catalysts were systematically characterized. Their catalytic performance was first evaluated in batch hydrogenation of neat NB at 160 °C and 1.6 MPa H2. Continuous tests were then conducted in a micro-packed-bed reactor using an ethanolic NB feed. Pt-Pd/C exhibited the best activity–selectivity balance among the RSAC-supported catalysts. It afforded >99.9% ANL selectivity and a high apparent early-stage turnover frequency (TOF) of 6594 h−1. Pt-Pd/C also suppressed over-hydrogenation and condensation-related side pathways. In continuous operation, Pt-Pd/C reached steady state within 2 h. It maintained approximately 87% NB conversion with near-quantitative ANL selectivity for 70 h. These results demonstrate the potential of RSAC-supported Pt-Pd catalysts for continuous liquid-phase NB hydrogenation.