Grubbs–Hoveyda type catalysts bearing a dicationic <i>N</i>-heterocyclic carbene for biphasic olefin metathesis reactions in ionic liquids

Koy, Maximilian; Altmann, Hagen J.; Autenrieth, Benjamin; Frey, Wolfgang; Buchmeiser, Michael R.

doi:10.3762/bjoc.11.178

Cited by 12 publications

(4 citation statements)

References 28 publications

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“…Ionic liquids (ILs) are thus the ideal solvents due to their lack of (or extremely low) vapor pressure, miscibility with polymers as well as organic compounds and metal catalysts (which makes most homogeneous catalytic reactions feasible), and high stability ranging from −30 to 300 °C. − These promising characteristics of ILs enable us to consider them as desirable solvents for synthesis of high-molecular-weight polyesters in the ADMET condensation polymerization. − Although olefin metathesis reactions in ILs have been known, − the reported examples of ADMET polymerization have been limited so far. − ,− For instance, the polymerization of 1,9-decadiene in 1- n -butyl-3-methyl imidazolium hexafluorophosphate ([Bmim]PF 6 ,) in the presence of RuCl 2 (PCy 3 ) 2 (CHPh) ( G1 ) at 50 °C afforded rather high molecular weight polymers (Scheme , M n = 1.08–1.92 × 10 4 ) . The polymerization of 1,4-bis(undec-10-en-1-yloxy)-triptycene conducted at 100 °C using G2 (initially 80 °C for 24 h, total of seven days) also gave a rather high molecular weight polymer ( M n = 1.15 × 10 4 ) .…”

Section: Introductionmentioning

confidence: 99%

Synthesis of High-Molecular-Weight Biobased Aliphatic Polyesters by Acyclic Diene Metathesis Polymerization in Ionic Liquids

2023

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Acyclic diene metathesis (ADMET) polymerization of an α,ω-diene monomer of bis(undec-10-enoate) with isosorbide (M1) using a RuCl2(IMesH2)(CH-2-O i Pr-C6H4) (HG2, IMesH2 = 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene) catalyst and conducted at 50 °C (in vacuo) in ionic liquids (ILs) afforded higher-molecular-weight polymers (P1, M n = 32 200–39 200) than those reported previously (M n = 5600–14700). 1-n-Butyl-3-methyl imidazolium hexafluorophosphate ([Bmim]PF6) and 1-n-hexyl-3-methyl imidazolium bis(trifluoromethanesulfonyl)imide ([Hmim]TFSI) were suitable as effective solvents among a series of imidazolium salts and the pyridinium salts. The polymerization of α,ω-diene monomers of bis(undec-10-enoate) with isomannide (M2), 1,4-cyclohexanedimethanol (M3), and 1,4-butanediol (M4) in [Bmim]PF6 and [Hmim]TFSI also afforded the higher-molecular-weight polymers. The M n values in the resultant polymers did not decrease even under the scale-up conditions (300 mg to 1.0 g scale, M1, M2, and M4) in the polymerizations in [Hmim]TFSI; the subsequent reaction of P1 with ethylene (0.8 MPa, 50 °C, and 5 h) gave oligomers (proceeded via depolymerization). Tandem hydrogenation of the resultant unsaturated polymers (P1) in a [Bmim]PF6–toluene biphasic system upon the addition of Al2O3 (1.0 MPa H2 at 50 °C) gave the corresponding saturated polymers (HP1), which waswere isolated by a phase separation in the toluene layer. The [Bmim]PF6 layer containing the ruthenium catalyst could be recycled without a decrease in the activity/selectivity of the olefin hydrogenation at least eight times.

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Section: Introductionmentioning

confidence: 99%

Synthesis of High-Molecular-Weight Biobased Aliphatic Polyesters by Acyclic Diene Metathesis Polymerization in Ionic Liquids

2023

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“…Tailored self-scavenging catalysts contain tags that facilitate the removal of both the catalyst and its byproducts after the reaction is complete. ,− Similar to heterogeneous catalysts, the syntheses of such complexes often requires lengthy and expensive modifications.…”

Section: Introductionmentioning

confidence: 99%

Semiheterogeneous Purification Protocol for the Removal of Ruthenium Impurities from Olefin Metathesis Reaction Products Using an Isocyanide Scavenger

Szczepaniak

Nogaś

Piątkowski

et al. 2019

Org. Process Res. Dev.

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A low-waste, time-economical, and scalable semiheterogeneous purification protocol for the removal of ruthenium residues from olefin metathesis (OM) reactions has been developed. It is based on the non-covalent immobilization of the commercially available isocyanide 1,4-bis(3-isocyanopropyl)piperazine (QA) on unmodified silica gel. The use of the heterogeneous scavenger QA@SiO 2 synthesized in situ during the purification process was shown to yield OM products with metal contamination usually below 5 ppm. Furthermore, the new purification protocol was effective on a gram scale in the ring-closing OM of an intermediate in the synthesis of cathepsin K inhibitors, leading to a product containing only 0.29 ppm Ru. Finally, QA was used in an aqueous medium and reduced the metal contamination from 9977 to 21 ppm.

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“…Although the benefit of using ionic liquid (IL) media for various polymerization processes, particularly for ring-opening metathesis polymerization (ROMP), is recognized in the literature, so far it has never been applied to the depolymerization of NR. The merits in the application of IL solvents in ROMP have been demonstrated, allowing for the synthesis of polymers in high yield, in a controlled way and with a low metal contamination; moreover, it affords the recycling of the catalytic phase. − …”

Section: Introductionmentioning

confidence: 99%

Controlled Metathetic Depolymerization of Natural Rubber in Ionic Liquids: From Waste Tires to Telechelic Polyisoprene Oligomers

Mouawia

Nourry

Gaumont

et al. 2016

ACS Sustainable Chem. Eng.

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A controlled degradation process enabling Natural Rubber (NR) depolymerization and using the olefin metathesis reaction in ionic liquid medium is reported. Using trihexyl-(tetradecyl)phosphonium chloride (Cyphos101) and N,N-dioctylimidazolium bromide (C8C8ImBr), low-dispersity telechelic polymers are produced. With N,N-dioctylimidazolium bromide (C8C8ImBr), the degradation process could be performed for five consecutive cycles with excellent control. This degradation process was successfully applied to waste tires.

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Grubbs–Hoveyda type catalysts bearing a dicationic N-heterocyclic carbene for biphasic olefin metathesis reactions in ionic liquids

Cited by 12 publications

References 28 publications

Synthesis of High-Molecular-Weight Biobased Aliphatic Polyesters by Acyclic Diene Metathesis Polymerization in Ionic Liquids

Synthesis of High-Molecular-Weight Biobased Aliphatic Polyesters by Acyclic Diene Metathesis Polymerization in Ionic Liquids

Semiheterogeneous Purification Protocol for the Removal of Ruthenium Impurities from Olefin Metathesis Reaction Products Using an Isocyanide Scavenger

Controlled Metathetic Depolymerization of Natural Rubber in Ionic Liquids: From Waste Tires to Telechelic Polyisoprene Oligomers

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