Kinetic Modeling of Reductive Alkylation of Aniline with Acetone Using Pd/Al₂O₃ Catalyst in a Batch Slurry Reactor

Abstract

The kinetics of reductive alkylation of aniline with acetone was studied in a slurry reactor under isothermal conditions in a temperature range of 378−408 K using 3% Pd/Al2O3 catalyst. Experimental data on concentration−time as well as hydrogen consumption−time profiles were obtained to study the effect of concentration of aniline, catalyst loading, and partial pressure of hydrogen. Separate controlled experiments were performed to understand the nature of the condensation reaction between aniline and acetone, which forms the Shiff's base intermediate. From the concentration−time profiles and the effect of reaction conditions, it was found that the noncatalytic equilibrium formation of the Shiff base intermediate was the slowest step in the multistep reaction sequence. Several rate equations were considered to fit the batch slurry reactor data, and rate models based on competitive dissociative adsorption of hydrogen and the reactive substrates in the rate-limiting catalytic steps were found to represent the experimental data. The kinetic parameters were evaluated by fitting the integral batch reactor data at different temperatures. The activation energies, heat of adsorption, and entropy of adsorption of all the reactant species were also evaluated.