Kinetic modelling of hydrogenation of butynediol using 0.2% Pd/c catalyst in a slurry reactor

Abstract

Hydrogenation of butynediol using 0.2% Pd/C catalyst was studied and rate equations for the various steps involved have been reported. Several experiments were carried out in a high pressure stirred slurry reactor in a temperature range of 303-353 K. It was observed that besides butenediol and butanediol, side products such as γ-hydroxybutyraldehyde, n-butanol, n-butyraldehyde and an acetal were also formed. The formation of γ-hydroxybutyraldehyde and acetal was confirmed by GC-MS and IR analysis and a reaction scheme has been proposed. Effect of catalyst loading, H₂ pressure, initial butynediol concentration and agitation speed on the rates as well as concentration-time behaviour was studied. The initial rates were found to be first order dependent on catalyst loading and H₂ pressure, while with respect to butynediol, an inhibition in the rate was observed. The kinetic parameters for the various reaction steps involved in this complex reaction system were evaluated by simulation of the experimental concentration-time data.