Sami Toppinen

The liquid phase hydrogenation of benzene and substituted alkylbenzenes over a nickel catalyst in a semi-batch reactor

Abstract The liquid phase hydrogenation kinetics of benzene, toluene, ethylbenzene and cumene was studied in a three-phase semibatch reactor at pressures of 20–40 bar and at temperatures of 95–140°C. The experimental kinetics was described with a rate equation based on rapid adsorption and desorption steps and slow consecutive hydrogen steps. A pseudo-homogeneous model neglecting the diffusion resistances in the catalyst particles was able to phenomenologically describe the observed kinetics, but numerical simulations showed that there exist significant concentration gradients in the particles. Therefore a complete dynamic heterogeneous model was developed for the reactor and the catalyst particles including the reaction-diffusion process. The kinetic parameters were re-determined using the heterogeneous reactiondiffusion model. The model enables the investigation of the reaction-diffusion effects and the dynamics of the catalyst particles.

Modelling of speciality chemicals production in liquid–liquid reactors—A case study: synthesis of diols

Abstract Generalized mass balance models were derived for semibatch liquid–liquid reactors, which are frequently used in the production of fine and speciality chemicals. The model comprises the reaction kinetics, liquid–liquid equilibria as well as interfacial mass transfer effects. The reactor model was applied on a case study, homogeneously catalyzed synthesis of diols through aldol condensation and Cannizzaro reaction. Rate equations for the process were obtained by applying steady-state approximations on ionic reaction intermediates. The rate equation were incorporated into the mass balances and tested with experimental kinetic data. The model was able to imitate the experimental behaviour of the two-phase system.