Polyethylene ionic liquid phase

Scheme 7.90 Preparation of polyethylene glycol-ionic liquid phases.

In a related study, the group of Bazureau applied their polyethylene glycol-grafted ionic liquid phases (ILPs) to the preparation of 2-thioxotetrahydropyrimidinones [105], After the initial formation of acrylate-bound ILPs utilizing acryloyl chloride in refluxing dichloromethane, several primary amines were attached in a Michael addi-... 

Various polymeric and solid supports, such as polyethylene glycol (PEG), can be used to immobilise these catalysts.[46 48] Exchanging the polymer support on the styrene moiety for charged ionic liquid tags affords complexes 38 and 39, which are retained to a significantly higher degree in the ionic liquid phase (Scheme 7.4). 

Bhanage and coworkers [62] investigated the reaction in polyethylene glycol and used the recycled rhodium phosphinite catalyst up to five times. Wasserscheid s group performed HAM in a continuous reactor operating with supported ionic liquid phase (SILP) catalysts [49]. A particular feature was that, by using a SILP catalyst based on neutral oxide and porous carbon supports and ILs of low basicity, aldol condensation could be fully suppressed. Alternatively, the reaction has been run with the assistance of a rhodium catalyst immobilized in a sol-gel matrix [73]. 

DBU DMC DMF EC EO EOS GSS ILs MBMTBP MEA MW PC PDMS PEG PEGda PEO PMPS PO PPG PPGda PTC PTHF PTMO PVP Diazabicyclo[5.4.0] -undec-7-ene Dimethylcarbonate Dimethylform amide Ethylene carbonate Ethylene oxide, oxyethylene Equation of state Gas-saturated solution Ionic liquids 2,2,-methylene-bis(4-methyl-6-tert-butylphenol) Monoethanolamine Molecular weight Propylene carbonate Polydimethylsiloxane Polyethylene glycol Poly(ethylene glycol) diacrylate Polyethylene oxide Poly(methylphenylsiloxane) Propylene oxide Poly(propylene glycol) Poly(propylene glycol) diacrylate Phase-transfer catalyst Poly(tetrahydrofuran) Polytetramethylene oxide Polyvinyl pyrrolidone... 

Systems have been developed that allow the recycling of catalysts. The first case study involved simple adsorption of proline onto silica gel [6], but the system suffered from a loss in enantioselectivity. More recently, promising results have been obtained with fluorous proline derivatives [64] used for aldol reactions the recycling of fluorous catalysts has been demonstrated using fluorous solid-liquid extraction. Solid phase-supported catalysts through covalent bonds [65] and through noncovalent interactions [66] were also used for aldol reactions. Proline and other catalysts can be recycled when ionic liquids or polyethylene glycol (PEG) were used as reaction solvents [67]. 

Figure 2. Different approaches of the variation of the application phase of oxo catalysts. FBS = fluorous biphase [multiphase] system PEG = polyethylene glycol NAIL = non-aqueous ionic liquid.

Volumetric and compressibility studies in aqueous solutions of alkali metal citrates and anunonium dtiates are relatively well documented in the literature [160, 162, 164, 168-187]. Usually, they were performed in the context of separation and purification of biomateiials in various two-phase aqueous systems with different polyethylene glycols, polypropylene glycols, polyviitylpyrrohdone, room temperature ionic liquids and amino adds. 

While many studies on kg in the two-phase liquid--solid system have been carried out only few have been reported for three-phase bubble columns (83,84). Most recently, Deckwer and Sanger (85) investigated liquid--solid mass transfer on suspended ionic resin beads in a bubble column, the range of the Schmidt number was varied from 137 to 5 x 10 by using aqueous solutions of polyethylene glycol. The findings were correlated by... 

In addition to nanoparticles, other precious metal catalyst structures have been investigated such as mesoporous nanostructured layers. In a series of publications Attard, Elliott, Bartlett, and co-workers described the formation of mesoporous Pt and PtRu films by lyotropic liquid crystalline phase templated electroless or electrochemical (faradaic) deposition [237-243]. Using non-ionic surfactants (e.g., polyethylene glycols such as C12EO8, CieEOs, and CisEOio) at concentrations above 30 wt% in order to assure the formation of a homogeneous liquid crystalline phase, the surfaetant moleeular aggregates in the bulk electrolyte could serve as templates for nanostruetured deposition of metal ions from the interstitial spaces. 

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