Markus Priske

Kinetics of cyclooctene hydroformylation for continuous homogeneous catalysis

The kinetics of Rh-catalysed cyclooctene hydroformylation were investigated, based on the mechanism described for a single tris(2,4-di-tert-butylphenyl)phosphite ligand coordinated to a rhodium center. The rate limiting step was found to be the coordination of cyclooctene to the metal center as suggested in literature. Parameters of the corresponding rate equation were estimated by nonlinear regression. Experimental data obtained from semi-batch reactions were compared with model predictions and shown to be in good agreement. A continuous jet-loop reactor with coupled nanofiltration was designed and the kinetics were validated.

Process design of integrated reaction and membrane separation by organic solvent nanofiltration using evolutionary algorithms

Abstract This paper shows a model-based design method of an integrated reaction and membrane separation process applied to the ligand-assisted hydroformylation of cyclooctene to cyclooctanecarbaldehyde. In order to demonstrate the economic potential of the applied organic solvent nanofiltration (OSN) membrane technology, the focus is set on cost optimisation varying simultaneously process configuration and process conditions. The process model is fed with kinetic data of cyclooctene hydroformylation reaction kinetics (TU Eindhoven) and experimental data of OSN membrane permeation (Evonik Industries AG). The resulting Mixed-Integer Non-Linear Programming (MINLP) problem is solved using an evolutionary algorithm. For the optimal processes, cost structures are presented and discussed.

Kinetic Explanation for the Temperature Dependence of the Regioselectivity in the Hydroformylation of Neohexene

The kinetics of Rh‐catalyzed neohexene hydroformylation were investigated with the bulky monodentate ligand tris(2,4‐di‐tert‐butylphenyl)phosphite. The hydrogenolysis of the Rh–acyl intermediate was identified as the rate‐limiting step for both the linear and the branched aldehydes. Rate equations for both aldehydes were derived and kinetic parameters were estimated. Increased aldehyde linearity at higher temperatures, frequently observed in hydroformylation, was elucidated by deuterioformylation experiments. These showed that at 100 °C the formation of linear Rh–alkyl was more reversible than the formation of the branched derivative. The ratio of linear to branched Rh–acyl species was determined by in situ high‐pressure IR spectroscopy experiments, which allowed the difference in the activation energies for the hydrogenolysis steps towards the aldehyde isomers to be quantified. The hydrogenolysis of Rh–acyl was found to be the step that caused the greatest temperature effect on the regioselectivity.