Hydrogenation process intensification of 2-nitro-4-acetylamino anisole by HiGee technology

The catalytic hydrogenation of 2-nitro-4-acetylamino anisole (NMA) is the main path to synthesize 2-amino-4-acetylamino anisole (AMA), belonging to a typical gas-liquid-solid system. However, the small mass transfer rate of traditional hydrogenation reactor can't match its intrinsic fast reaction rate, resulting in the low hydrogenation efficiency. In this work, a rotating packed bed (RPB) reactor with excellent mass transfer performance was applied for the hydrogenation process intensification of NMA. The characterization analysis of the commercial Raney-Ni catalyst shows that the liquid-solid mass transfer resistance during the reaction process can be ignored, and improving the gas-liquid mass transfer rate is the key to improve the macroscopic reaction rate. The effects of operating conditions (solvent, rotational speed, hydrogen pressure, temperature, and catalyst dosage) on NMA conversion and AMA selectivity were investigated. A macro-kinetic equation of NMA catalytic hydrogenation in the RPB reactor was proposed. Under optimized conditions, the NMA was completely converted in the RPB reactor within 30 min, while it took 4 h in the stirred tank reactor. The overall reaction efficiency of RPB reactor was increased by 87.5 % in comparison with STR. This study provides practical guidance for the industrial application of RPB reactor for gas-liquid-solid hydrogenation.