Hydrogenation of 2,4-Dinitrotoluene Using a Supported Ni Catalyst: Reaction Kinetics and Semibatch Slurry Reactor Modeling

Abstract

The kinetics of hydrogenation of 2,4-dinitrotoluene (2,4-DNT) using a 10% Ni supported on zeolite Y (10% Ni/HY) powdered catalyst (dp = 1 × 10-5 m) was studied experimentally in a semibatch slurry reactor over a temperature range of 333−363 K. The effects of reaction temperature, H2 pressure, concentration of 2,4-DNT and catalyst loading on the concentration−time and H2 consumption−time profiles were studied under isothermal conditions. To explain the rate behavior of this complex, consecutive, and parallel reaction, several rate expressions were derived based on Langmuir−Hinshelwood type rate mechanisms. The rate equations that were derived assuming the reaction between competitively adsorbed organic species and dissociatively adsorbed hydrogen as the rate-limiting step were found to represent the kinetics best. Quantitative analysis of the experiments performed under the chosen conditions (temperature, 333−363 K; H2 pressure, 1.3−5.4 MPa; 2,4-DNT concentration, 0.14−0.55 kmol/m3) indicated that the rate data obtained were under the kinetic regime. The rate and equilibrium parameters were evaluated for the different steps involved in the reaction network. A semibatch slurry reactor model has been developed to predict both integral concentration−time and H2 consumption−time profiles and was compared with experimental data at different sets of initial conditions. An excellent agreement between the model predictions and the experimental data was observed.