New Hydroformylation Catalysts

Dr. Jens Holz


The hydroformylation reaction, the transition-metal catalyzed synthesis of aldehydes by the addition of carbon monoxide and hydrogen to an olefin, is one of the most important industrially applied and homogeneously catalyzed reaction to date. Depending on the substrate (olefin) and the catalyst, terminal, or branched aldehydes (n- or iso-aldehydes) are formed. The latter occur predominantly as a racemate or, with appropriate control by the catalyst, also enantiomeric-enriched isoaldehydes can be obtained. Most of these aldehydes obtained are used as starting materials for the synthesis of plasticizer alcohols. Enantiomerically pure isoaldehydes are of interest as precursors for pharmaceuticals (antiphlogistic).1

Our work focuses on the synthesis of new and patent-free P(III)-compounds, the determination of their capability as ligands in the rhodium-catalyzed carbonylation,2 and the investigations into other catalytically active metals (e. g. cobalt catalysis).3 We seek for a better description of catalysis by investigating mechanistic aspects and observing the concentration of organometallic intermediates in a time resolved manner. Chemometric tools are applied which allow for kinetic evaluation of spectroscopic data. Respective methods used by us are in-sit HP-NMR and in situ FTIR spectroscopy (for further details, see below).4,5 We are mainly interested in isomerizing Hydroformylation. This reaction allows the kinetically controlled access to desired n-aldehydes from inexpensive internal olefins by a consecutive reaction of olefin isomerization and selective terminal hydroformylation (see Figure 1). With our synthesized rhodium-catalysts (mainly with bidentate P-ligands such as diphosptes and diphosphonites), n-regioselectivities of up to 99% and turnover frequencies of up to 6000 mololefin x molcatalysts-1 x h-1 were achieved.6-8 In recent years, however, the requirements for the desired carbonylation product have shifted. Instead of the maximum yield of n-aldehydes, the focus is now on achieving reaction products with a defined composition of n- and iso-aldehydes. In ligand synthesis, this means new approaches and challenges in terms of the structural and electronical properties of the compounds in contrast to the former P-compounds prepared for maximum n-selectivity.

Based on our results, around ten patent applications were filed by our cooperation partner Evonik AG in the years 2019-2021. A registration for 2022 is currently being processed.


Beside the dominant hydroformylation as the main focus of our work, activities in the field of hydrogenation (Rh-, Ru-, and Ir-catalysis) remains part of our investigations. In addition to the work in basic research, e. g. synthesis of new (chiral) phosphines,9,10 or other special problems,11 we also investigate specific tasks in the implementation of hydrogenations as part of projects in the field of industry or pharmacy to find appropriate solutions for our contractual partners.