Verknüpfung katalytischer Reaktionen in Hinblick auf Katalysator-Recycling und die Anwendung in kontinuierlich betriebenen Reaktoren

Strohmann, Marc; Leitner, Walter (Thesis advisor); Liauw, Marcel (Thesis advisor); Vorholt, Andreas (Thesis advisor)

Aachen : RWTH Aachen University (2022, 2023)
Dissertation / PhD Thesis

Dissertation, RWTH Aachen University, 2022

Abstract

This work deals with the design and execution of linked catalytic reactions in the form of a tandem or cascade reaction. Cascade reactions involve the connection of two partial reactions in series in a continuously operated plant without intermediate work-up. This type of linkage makes it possible to reduce costs and waste from processes and contribute to sustainability when a tandem reaction is not possible. In two projects, the prerequisites for a cascade reaction and the best way to carry it out were worked out. Both projects dealt with a process consisting of two substeps that cannot be linked as a tandem reaction, but only as a cascade reaction. For the first project, the conversion of the biomass-derived compound furfuralacetone into the potential biofuel molecule 2-butyltetrahydrofuran (BTHF) was investigated. The conversion consists of the complete hydrogenation of furfural acetone and the subsequent deoxygenation to BTHF. Initially, the two substeps were studied separately, a common solvent was found, and suitable catalysts were compared, focusing on the use of commercial heterogeneous catalysts. After optimizing both reactions on a small scale, they were transferred to a continuous operation. The cascade reaction was successfully demonstrated in a tailor-made miniplant. The second project dealt with the preparation of branched long-chain amines - which are of interest for application as surfactants - starting from terminal olefins. First, a multiphase catalyst system for the hydroformylation/aldol condensation tandem reaction was developed, which allowed the conversion of the olefins to unsaturated aldehydes. The green solvent polyethylene glycol turned out to be crucial for the reaction, as it both enhanced the activity of the basic aldol catalyst and allowed recycling of the homogeneous catalyst system. Further conversion of the aldol products to the branched amines via reductive amination was also successfully carried out and a catalyst recycling was developed. The combination of the two tandem reactions was realized on a small scale and it was discussed how the cascade reaction could be carried out in continuous operation. The findings of both projects finally led to a decision tree for the general design of cascade reactions.

Institutions

• Department of Chemistry [150000]
• Chair of Technical Chemistry and Petrochemistry [154110]