Issue 18, 2022

Mapping catalyst activation, turnover speciation and deactivation in Rh/PPh3-catalysed olefin hydroformylation

Abstract

We report new insights into the fate of the precious metal during hydroformylation catalysis of 1-hexene with Rh/PPh3 complexes using multi-nuclear operando FlowNMR spectroscopy. By applying selectively excited 1H and 31P{1H} NMR pulse sequences we were able to characterise and quantify key hydrido-rhodium and acyl-rhodium intermediates formed during turnover as well as dormant dimeric carbonyl complexes. The quantitative catalyst distribution maps derived this way explain catalyst stability and activity across a range of reaction conditions, including why CO-lean conditions give faster hydroformylation catalysis through the suppression of dimer and cluster formation. The activation behaviour of five commonly used precursors and the thermal stability of the phosphine-hydrido complex [RhH(CO)(PPh3)3] have been investigated, and the benefits of applying controlled temperature gradients for quantitative FlowNMR spectroscopic reaction monitoring of dynamic catalyst systems are demonstrated.

Graphical abstract: Mapping catalyst activation, turnover speciation and deactivation in Rh/PPh3-catalysed olefin hydroformylation

Supplementary files

Article information

Article type
Paper
Submitted
16 Feb 2022
Accepted
18 Jul 2022
First published
26 Jul 2022
This article is Open Access
Creative Commons BY license

Catal. Sci. Technol., 2022,12, 5501-5516

Mapping catalyst activation, turnover speciation and deactivation in Rh/PPh3-catalysed olefin hydroformylation

A. Bara-Estaún, C. L. Lyall, J. P. Lowe, P. G. Pringle, P. C. J. Kamer, R. Franke and U. Hintermair, Catal. Sci. Technol., 2022, 12, 5501 DOI: 10.1039/D2CY00312K

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