Kinetic modelling of a complex consecutive reaction in a slurry reactor: hydrogenation of phenyl acetylene

Abstract

Kinetics of hydrogenation of phenyl acetylene to styrene to ethyl benzene using Pd/C catalyst has been reported. The experiments were carried out in a mechanically agitated autoclave over a temperature range of 15-45° C. Effect of catalyst loading, H₂ pressure, concentrations of reactants and products on the rate of hydrogenation as well as the concentration profile in a batch reactor was investigated. The analysis of initial rates showed that the data were in kinetic regime for 0.1% Pd/C catalyst. For interpretation of the kinetics, the observed concentration time data were directly used and the rate parameters evaluated using a simulation model for the batch reactor. It was found that the rate of hydrogenation was strongly inhibited in the presence of phenyl acetylene, while styrene and ethyl benzene showed negligible effects. The activation energies observed for the two consecutive steps were 51.5 and 53.6 kJ/mol, respectively.