<i>Operando</i> characterization of rhodium catalyst degradation in hydroformylation

Gerlach, Martin; Jameel, Froze; Seidel‐Morgenstern, Andreas; Stein, Matthias; Hamel, Christof

doi:10.1039/d2cy01807a

Cited by 5 publications

(8 citation statements)

References 50 publications

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“…When the oxidation was carried on, the loss of a new triphenylphosphine ligand caused a brown coloration and then the precipitation of black palladium. Similar observations have been made by M. Gerlach et al [ 48 ] who monitored the oxidation of ligands from a rhodium catalyst by infrared technology. With that mechanism in mind, in Figure 3 it was possible to theoretically determine the degradation process of the PdCl 2 (PPh 3 ) 2 .…”

Section: Introductionsupporting

confidence: 85%

Recovery of Homogeneous Platinoid Catalysts from Pharmaceutical Media: Review on the Existing Treatments and the Perspectives of Membrane Processes

Magne,

Carretier,

Ubiera Ruiz

et al. 2023

Membranes

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Catalyst recovery is a major challenge for reaching the objectives of green chemistry for industry. Indeed, catalysts enable quick and selective syntheses with high reaction yields. This is especially the case for homogeneous platinoid catalysts which are almost indispensable for cross-coupling reactions often used by the pharmaceutical industry. However, they are based on scarce, expensive, and toxic resources. In addition, they are quite sensitive and degrade over time at the end of the reaction. Once degraded, their regeneration is complex and hazardous to implement. Working on their recovery could lead to highly effective catalytic chemistries while limiting the environmental and economic impacts of their one-time uses. This review aims to describe and compare conventional processes for metal removal while discussing their advantages and drawbacks considering the objective of homogeneous catalyst recovery. Most of them lead to difficulty recycling active catalysts due to their ability to only treat metal ions or to chelate catalysts without the possibility to reverse the mechanism. However, membrane processes seem to offer some perspectives with limiting degradations. While membranes are not systematically the best option for recycling homogeneous catalysts, current development might help improve the separation between pharmaceutical active ingredients and catalysts and enable their recycling.

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Section: Introductionsupporting

confidence: 85%

Recovery of Homogeneous Platinoid Catalysts from Pharmaceutical Media: Review on the Existing Treatments and the Perspectives of Membrane Processes

Magne,

Carretier,

Ubiera Ruiz

et al. 2023

Membranes

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“…Thus, direct oxidation with O 2 is unlikely. The deactivation of ligands with hydroperoxide, which can be formed from olefins and oxygen at elevated temperatures, has been reported in the literature. , In deactivation experiments with tert -buylhydroperoxide, complete oxidation of the ligand to the signal at −3 ppm was observed within 10 min of reaction time, and the masses from APCI MS spectra could be assigned to oxidized Biphephos and a clear shift of the signals in the 1 H NMR spectrum was observed (SI, Figures S29–S31). This indicates that oxygen contaminants only play a major role in combination with the substrate.…”

Section: Resultsmentioning

confidence: 68%

“…Smaller signals were seen at the baseline, which are likely formed by CO and Biphephos-bridged Rh clusters when the synthesis gas pressure was relieved after the reaction and CO ligands partly dissociated from the complex. The formation of such clusters has been reported in the literature. ,− C is expected to be an Abramov reaction product, D consists of hydrolyzed products, and E is the oxidized ligand, as summarized in the introduction (Scheme ). To identify these signals, deactivation studies with the Biphephos ligand were performed.…”

Section: Resultsmentioning

confidence: 87%

Studying the Recycling and Deactivation of Rh/Biphephos Complexes in the Isomerization–Hydroformylation Tandem Reaction

Vossen,

Patzina,

Leitner

et al. 2024

ACS Sustainable Chem. Eng.

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Rh/Biphephos is a widely used homogeneous catalyst for the hydroformylation of internal olefins and mixtures of olefins due to its rapid isomerization and high n:iso selectivity. In this work, the recycling of the catalyst via distillation in high-boiling propylene carbonate as a catalyst phase solvent in the hydroformylation of internal olefins was investigated. In an initial recycling experiment, the catalyst was recycled 6 times before the Biphephos ligand was fully decomposed via oxidation. Deactivation studies using NMR and atmospheric pressure chemical ionization mass spectrometry (APCI MS) showed the sensitivity of the phosphite ligand toward water, oxygen originating from air, and nonanal. After purification of the ligand via crystallization, the ligand barely showed any sensitivity toward these contaminants, indicating an enhancement of decomposition by the impurities in the ligand. Oxidation of the ligand still occurred under the reaction conditions due to the formation of hydroperoxides of the substrate with oxygen traces. With these learnings, the improved stability of the catalyst was demonstrated in a new recycling experiment with less than 20% of Biphephos having decomposed after 10 runs.

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“…The lability of transition metal complexes as catalysts towards oxygen and oxidants is an important aspect. 55 The impact of the addition of air on the hydrido complex [HRh(CO) 2 (P∩P)] was studied by in situ IR-spectroscopy. The catalyst complex was generated by the preformation at standard conditions ([Rh] = 1 mM, [P∩P] = 1 mM, p (CO/H 2 ) = 2 MPa, ϑ = 50 °C, t = 2 h).…”

Section: Resultsmentioning

confidence: 99%

In situ spectroscopic investigations on BiPhePhos modified rhodium complexes in alkene hydroformylation

Leidecker,

Peña Fuentes,

König

et al. 2024

Catal. Sci. Technol.

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Operando characterization of rhodium catalyst degradation in hydroformylation

Abstract: For a comprehensive understanding of catalyst stability, knowledge of deactivation processes is an important keystone in addition to activity and selectivity. The underlying mechanisms and kinetics of deactivation help to...

Cited by 5 publications

References 50 publications

Recovery of Homogeneous Platinoid Catalysts from Pharmaceutical Media: Review on the Existing Treatments and the Perspectives of Membrane Processes

Recovery of Homogeneous Platinoid Catalysts from Pharmaceutical Media: Review on the Existing Treatments and the Perspectives of Membrane Processes

Studying the Recycling and Deactivation of Rh/Biphephos Complexes in the Isomerization–Hydroformylation Tandem Reaction

In situ spectroscopic investigations on BiPhePhos modified rhodium complexes in alkene hydroformylation

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