PEG-Modified Ligands for Catalysis and Catalyst Recycling in Thermoregulated Systems

Hermanns, Ellen; Hasenjäger, Jens; Drießen‐Hölscher, Birgit

doi:10.1007/3418_2006_061

Cited by 5 publications

(1 citation statement)

References 16 publications

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“…These approaches are surveyed in several recent reviews [11][12][13][14], and include the addition of modifiers or compatibilizers [15] such as cosolvents (mostly methanol, ethanol) [16][17][18][19][20][21][22], amphiphilic/thermo-regulated ligands and cyclodextrins [23][24][25] to improve mass transport as well as surfactants (cationic, anionic, double long chain cationic) to increase the interfacial area by emulsion and microemulsion methods [26][27][28][29][30][31][32][33][34][35][36][37]. Other interesting approaches apply thermomorphic methods with catalyst anchoring on lower critical solution temperature (LCST) polymers that become lipophilic at high temperatures [38][39][40][41][42][43][44][45] and on micellar formation with catalyst anchoring on the hydrophobic tail of surfactants [46][47][48]. Note that, in the literature, the term "micellar catalysts" is often used for the "mini-emulsion approach" with dramatic increase of the interface area by swollen micelles [49][50][51][52].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Nixantphos Core-Functionalized Amphiphilic Nanoreactors and Application to Rhodium-Catalyzed Aqueous Biphasic 1-Octene Hydroformylation

et al. 2020

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A latex of amphiphilic star polymer particles, functionalized in the hydrophobic core with nixantphos and containing P(MAA-co-PEOMA) linear chains in the hydrophilic shell (nixantphos-functionalized core-crosslinked micelles, or nixantphos@CCM), has been prepared in a one-pot three-step convergent synthesis using reversible addition-fragmentation chain transfer (RAFT) polymerization in water. The synthesis involves polymerization-induced self-assembly (PISA) in the second step and chain crosslinking with di(ethylene glycol) dimethacrylate (DEGDMA) in the final step. The core consists of a functionalized polystyrene, obtained by incorporation of a new nixantphos-functionalized styrene monomer (nixantphos-styrene), which is limited to 1 mol%. The nixantphos-styrene monomer was synthesized in one step by nucleophilic substitution of the chloride of 4-chloromethylstyrene by deprotonated nixantphos in DMF at 60 °C, without interference of either phosphine attack or self-induced styrene polymerization. The polymer particles, after loading with the [Rh(acac)(CO)2] precatalyst to yield Rh-nixantphos@CCM, function as catalytic nanoreactors under aqueous biphasic conditions for the hydroformylation of 1-octene to yield n-nonanal selectively, with no significant amounts of the branched product 2-methyl-octanal.

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Section: Introductionmentioning

confidence: 99%

Synthesis of Nixantphos Core-Functionalized Amphiphilic Nanoreactors and Application to Rhodium-Catalyzed Aqueous Biphasic 1-Octene Hydroformylation

et al. 2020

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Thermomorphic Catalysts

Bergbreiter

2009

Recoverable and Recyclable Catalysts

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Core–Shell Nanoreactors for Efficient Aqueous Biphasic Catalysis

Zhang

Cardozo

Chen

et al. 2014

Chemistry A European J

160

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Water-borne phosphine-functionalized core-cross-linked micelles (CCM) consisting of a hydrophobic core and a hydrophilic shell were obtained as stable latexes by reversible addition-fragmentation chain transfer (RAFT) in water in a one-pot, three-step process. Initial homogeneous aqueous-phase copolymerization of methacrylic acid (MAA) and poly(ethylene oxide) methyl ether methacrylate (PEOMA) is followed by copolymerization of styrene (S) and 4-diphenylphosphinostyrene (DPPS), yielding P(MAA-co-PEOMA)-b-P(S-co-DPPS) amphiphilic block copolymer micelles (M) by polymerization-induced self-assembly (PISA), and final micellar cross-linking with a mixture of S and diethylene glycol dimethacrylate. The CCM were characterized by dynamic light scattering and NMR spectroscopy to evaluate size, dispersity, stability, and the swelling ability of various organic substrates. Coordination of [Rh(acac)(CO)2 ] (acac=acetylacetonate) to the core-confined phosphine groups was rapid and quantitative. The CCM and M latexes were then used, in combination with [Rh(acac)(CO)2 ], to catalyze the aqueous biphasic hydroformylation of 1-octene, in which they showed high activity, recyclability, protection of the activated Rh center by the polymer scaffold, and low Rh leaching. The CCM latex gave slightly lower catalytic activity but significantly less Rh leaching than the M latex. A control experiment conducted in the presence of the sulfoxantphos ligand pointed to the action of the CCM as catalytic nanoreactors with substrate and product transport into and out of the polymer core, rather than as a surfactant in interfacial catalysis.

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PEG-Modified Ligands for Catalysis and Catalyst Recycling in Thermoregulated Systems

Cited by 5 publications

References 16 publications

Synthesis of Nixantphos Core-Functionalized Amphiphilic Nanoreactors and Application to Rhodium-Catalyzed Aqueous Biphasic 1-Octene Hydroformylation

Synthesis of Nixantphos Core-Functionalized Amphiphilic Nanoreactors and Application to Rhodium-Catalyzed Aqueous Biphasic 1-Octene Hydroformylation

Thermomorphic Catalysts

Core–Shell Nanoreactors for Efficient Aqueous Biphasic Catalysis

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