Homogenous Iridium Catalysts for Biomass Conversion

Kirchhecker, Sarah; Spiegelberg, Brian; Vries, Johannes G. de

doi:10.1007/3418_2020_72

Cited by 4 publications

(5 citation statements)

References 110 publications

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“…Further reduction of the catalyst loading to 14 ppm (0.0014 mol%) allows a remarkable TON LA of 15,000 (entries 27 and 28). activity, reaching similar conversions in only 0.75 h and selectivities to LA higher than 90 % (entries [16][17][18][19][20]. Under these conditions, catalyst 5 was the most efficient, with total conversion and a 93% selectivity to LA (entry 19).…”

Section: Dehydrogenation Of Glycerol To Lactic Acidmentioning

confidence: 94%

“…The better performance of KOH is likely related to the higher solubility of potassium hydroxide in glycerol. Increasing the temperature from 130 to 150 • C resulted in an increase in activity, reaching similar conversions in only 0.75 h and selectivities to LA higher than 90% (entries [16][17][18][19][20]. Under these conditions, catalyst 5 was the most efficient, with total conversion and a 93% selectivity to LA (entry 19).…”

Section: Dehydrogenation Of Glycerol To Lactic Acidmentioning

confidence: 96%

“…Under these conditions, catalyst 5 was the most efficient, with total conversion and a 93% selectivity to LA (entry 19). On the other hand, the influence of the amount of KOH on the catalytic activity has also been studied using the same amount of catalyst 5(0.01 mmol, entry 19). A decrease in the amount of KOH leads to a drastic decrease in LA formation (entries [21][22], and the activity did not improve when the amount of KOH was increased to 6 mmol (entry 23).…”

Section: Dehydrogenation Of Glycerol To Lactic Acidmentioning

confidence: 99%

“…In this regard, transition metal catalysts based on PNP pincer ligands have shown remarkable activity in the dehydrogenation of a range of substrates, such as formic acid [12], primary and secondary alcohols [13], including methanol [14,15], nitrogencontaining heterocycles [16] or even oxidative dehydrogenation of glycerol to lactate [17,18]. Currently, Ir-NHCs complexes play a prominent role in the area, as they have been revealed as robust catalysts for a number of dehydrogenation reactions, including the selective oxidation of glycerol [19]. In particular, carbonyl Ir-NHC catalysts such as [Ir(CO) 2 (IMe) 2 ] + (IMe = 1,3-dimethylimidazol-2-ylidene) [20], [Ir(CO) 2 {MeIm(pyridin-2-ylmethyl)}] + [21] or even a related water-soluble zwitterionic iridium catalyst featuring NHC ligands with sulfonate-functionalized wingtips [22,23] have shown an excellent catalytic performance in the selective acceptorless dehydrogenation of glycerol to lactate.…”

Section: Introductionmentioning

confidence: 99%

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Selective Oxidation of Glycerol via Acceptorless Dehydrogenation Driven by Ir(I)-NHC Catalysts

et al. 2022

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Iridium(I) compounds featuring bridge-functionalized bis-NHC ligands (NHC = N-heterocyclic carbene), [Ir(cod)(bis-NHC)] and [Ir(CO)2(bis-NHC)], have been prepared from the appropriate carboxylate- or hydroxy-functionalized bis-imidazolium salts. The related complexes [Ir(cod)(NHC)2]+ and [IrCl(cod)(NHC)(cod)] have been synthesized from a 3-hydroxypropyl functionalized imidazolium salt. These complexes have been shown to be robust catalysts in the oxidative dehydrogenation of glycerol to lactate (LA) with dihydrogen release. High activity and selectivity to LA were achieved in an open system under low catalyst loadings using KOH as a base. The hydroxy-functionalized bis-NHC catalysts are much more active than both the carboxylate-functionalized ones and the unbridged bis-NHC iridium(I) catalyst with hydroxyalkyl-functionalized NHC ligands. In general, carbonyl complexes are more active than the related 1,5-cyclooctadiene ones. The catalyst [Ir(CO)2{(MeImCH2)2CHOH}]Br exhibits the highest productivity affording TONs to LA up to 15,000 at very low catalyst loadings.

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Section: Dehydrogenation Of Glycerol To Lactic Acidmentioning

confidence: 94%

Section: Dehydrogenation Of Glycerol To Lactic Acidmentioning

confidence: 96%

Section: Dehydrogenation Of Glycerol To Lactic Acidmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Selective Oxidation of Glycerol via Acceptorless Dehydrogenation Driven by Ir(I)-NHC Catalysts

et al. 2022

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“…[16][17][18] The procedure employed recyclable Cp*IrCl2(NHC) pre-catalysts. The utility of Iridium catalysts for converting biomass has been noted [19].…”

Section: Introductionmentioning

confidence: 99%

Catalytic Cascade for Biomass Valorisation: Coupled Hydrogen Transfer Initiated Dehydration (Htid) and Self-Aldol Condensation (Sac) for the Synthesis of 2-Methyl-Pent-2-Enal from 1,3-Propanediol

Ma,

Wang,

Lorenzini

et al. 2024

Preprint

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A one-pot, one-step protocol combining hydrogen transfer initiated dehydration (HTID) of 1,3-propanediol (1,3-PDO), catalysed by [Cp*IrCl2(NHC)] (Cp* = pentamethylcyclopentadienyl; NHC = carbene ligand) complexes (1-5H and 1-3F), and self-aldol condensation (SAC) of propanal (2), allowed selective production of aldehyde 2-methyl-pent-2-enal (3), in ionic liquids with high substrate conversion. The Ir(III) pre-catalysts, and the ionic liquids, were recyclable. 3 could also be selectively produced in the presence of water, and in neat 1,3-PDO. The efficient, selective delivery of a value-added chemical from 1,3-PDO, a major product of many whole cell bacterial fermentation processes, shows that the combination of chemo-catalytic processing of the chemical platform via Cp*IrCl2(NHC) - catalysed HTID / SAC with bio-catalysis has the potential to allow direct valorisation of the bio-renewable feedstocks, such as waste glycerol and sugars, into valuable chemicals.

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Use of Iridium‐Catalyzed Transfer Vinylation for the Synthesis of Bio‐Based (bis)‐Vinyl Ethers

Spiegelberg

Jiao²,

Grauke

et al. 2022

Adv Synth Catal

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The iridium catalyzed transfer vinylation of bio‐based polyols and of other alcohols and phenols with interesting structural motifs was accomplished with vinyl acetate in 2‐MeTHF as a green solvent. The optimized synthetic procedure has as main advantages the use of catalytic instead of stoichiometric amounts of base and high selectivities towards the formation of bis‐vinyl ethers as a result of the suppression of the acetal formation reaction that typically occurs in the vinylation of diols. In addition, the thermodynamically preferred transesterification reaction leading to the acetate esters and bis‐esters was completely suppressed. DFT calculations revealed an iridium‐acetate complex as the active catalytic species and they disclosed the importance of the carbonyl group of vinyl acetate for the formation of a six‐membered cyclic intermediate.

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Homogenous Iridium Catalysts for Biomass Conversion

Cited by 4 publications

References 110 publications

Selective Oxidation of Glycerol via Acceptorless Dehydrogenation Driven by Ir(I)-NHC Catalysts

Selective Oxidation of Glycerol via Acceptorless Dehydrogenation Driven by Ir(I)-NHC Catalysts

Catalytic Cascade for Biomass Valorisation: Coupled Hydrogen Transfer Initiated Dehydration (Htid) and Self-Aldol Condensation (Sac) for the Synthesis of 2-Methyl-Pent-2-Enal from 1,3-Propanediol

Use of Iridium‐Catalyzed Transfer Vinylation for the Synthesis of Bio‐Based (bis)‐Vinyl Ethers

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