CO-Degassing in a Segmented Slug Flow Reactor Enables Continuous Linear Alcohol Formation from Alkenes using a single, non-assisted Rh-catalyst by Switching Between Hydroformylation and Aldehyde Reduction

We investigated the continuous, tandem catalytic reductive hydroformylation of 1-octene in a segmented slug flow reactor using a single catalyst enabled by CO degassing. Higher alcohols are of significant industrial importance and are traditionally produced through a two-step process. The use of rhodium-based catalysts offers advantages in terms of activity and selectivity towards linear alcohols; however, carbon monoxide (CO) inhibits catalytic activity in the subsequent reduction step. An innovative approach is presented here, where CO is selectively removed from the reaction mixture after hydroformylation utilizing a semi-permeable AF2400 membrane in a tube-in-tube setup to enhance reaction efficiency. The results demonstrated a notable improvement in yields, achieving 67.1% yield of l-nonanol with an impressive linear-to-branched (l/b) ratio of 10.6 after a residence time of only 27.6 minutes. This study highlights the significance of effective degassing and demonstrates the potential for sustainable optimization of reductive hydroformylation in continuous flow operations, showcasing that nearly full conversion can be achieved under optimized conditions with comparatively low catalyst loading of 0.5 mol.-%.