Kinetic modeling of acetophenone hydrogenation in an autoclave and jet loop reactor

As a model reaction for hydrogenation in the pharmaceutical industry, acetophenone (AP) hydrogenation using gaseous hydrogen and a Pd/C catalyst was investigated in an autoclave and a jet loop reactor (JLR) with approximately a 50‑times higher reaction volume. The influence of hydrogen pressure and initial AP concentration was studied in both reactors, and variations in water concentration were specifically tested in the autoclave. The stirred autoclave reactor operated without hydrogen gas-liquid mass transfer limitations, and a simple first order rate law model accurately described conversion and product yields for experiments conducted at low AP concentrations. A Langmuir–Hinshelwood (L-H) model featuring competitive and dissociative hydrogen adsorption was developed and successfully fitted all the autoclave experiments. This model also successfully predicted the JLR data. At low circulation rates, the hydrogenation in the JLR was limited by gas-liquid mass transfer; however, this limitation was effectively overcome by increasing the circulation flow.