Integrated electrochemical CO 2 reduction and hydroformylation.

The development of integrated multi-catalyst processes has become of high interest to transform abundant feedstocks or environmental pollutants to commodity chemicals in a one pot, one pass fashion. Specifically, CO 2 poses a large environmental burden and would thus be a desirable, relatively abundant C1 source in multi-step synthetic chemistry. Herein we disclose the synthesis of aldehydes from CO 2 via the integration of electrochemical CO 2 reduction (CO 2 RR) and hydroformylation, taking advantage of the typically unwanted concomitant hydrogen evolution (HER) to generate the necessary CO and H 2 needed for hydroformylation. Though typical hydroformylation catalysts based on Rh would be deactivated under CO 2 RR conditions, we circumvent this limitation by spatially segregating our CO 2 RR and hydroformylation systems in a vial-in-vial reactor, while allowing CO and H 2 transport between catalyst sites. In this manner, 97% aldehyde yield from CO 2 RR and styrene was achieved selectively using a classic homogeneous hydroformylation catalyst in HRh(CO)(PPh 3 ) 3 , and 43% aldehyde yield was obtained using a heterogenized version of this Rh catalyst onto mesoporous silica. This work not only repurposes undesired HER in CO 2 RR and prepares aldehydes from CO 2 without added H 2 , but expands the scope of processes that transform feedstocks all the way to commodity chemicals in a one pass manner.