Polyethylene glycol hydroformylation

Keywords Immobilization Thermoregulated catalysis Thermomorphic ligands Hydroformylation Polyethylene glycol modified phosphites... 

TABLE 8 Data Characterizing Catalytic Hydroformylation of Various Olefins with Rhodium Polyethylene Glycolate Complex.°... 

Although organic solvents were used in the workup, it might be possible to use filtration plus ultrafiltration, followed by distillation instead. Hydroformylation of 1-hexene has been achieved in polyethylene glycol by using a cobalt catalyst containing polyethyleneoxy substitu-tents.254 The catalyst phase was separated for reuse. 

Rhodium complexes generated from the polyethylene glycol)-functionalized phosphine 9 (n = 1, x = 0, R = Me, Bu), which should behave as a nonionic surfactant and be able to induce micelle formation, have been used as catalysts in the hydroformylation of 1-dodecene in an aqueous/organic two-phase system [31]. The conversion of 1-dodecene was 80% and the n/iso ratio 60 40, with no carryover of the rhodium catalyst into the organic phase. The Rh/9 (n = 1, x = 0, R = Me, Bu) catalyst remained active after one recycle step [31],... 

Apparently, no colloids are formed when polyethylene glycol is added to rhodium trichloride hydrate to obtain a water-soluble rhodium polyethylene glycolate highly active in the hydroformylation of heavy alkenes such as dodec-l-ene [75]. Such a system does not require the presence of other ligands and works efficiently at 70-120 bar. Besides a hypothesis in which it is envisioned a migration of the catalyst into the organic phase, a model where the reaction takes place in the interphase, due to the presence of polyethylene glycol, is favored. 

To increase the hpophihc character, cosolvents can be added to the classical RCH/RP system. Solvents like methanol, ethanol, polyethylene glycol strongly increase the hydroformylation rate [8]. The potential disadvantages of these cosolvents are leaching into the organic phase and their reactivity towards acetals. Leaching of catalyst and hgand seems to be no problem, provided that certain concentrations of cosolvents are not... 

Figure 2.14 Diphosphines suitable as ligands for Pt- or Rh-catalyzed hydroformylation linked to polystyrene (PS), polyethylene glycol-polystyrene (PEG-PS) resins, or polyethylene glycol...

Hydroformylation of 1-nonene affords -decanal (caprinaldehyde). The reaction can be advantageously carried out with a water-soluble Rh(TPPTS) catalyst, which gives after pretreatment in water in polyethylene glycol (PEG 150 or PEG 200) as solvent n-decanal with a ratio Hb = 98 2 (Scheme 6.6, n=l) [54]. Caprinaldehyde has a sweet floral scent that is reminiscent of orange peel. Upon dilution it gives a fresh odor. It occurs in many essential oils (e.g., neroli oil and citrus peel oils). It is employed in perfumery and as a flavoring agent in the food industry. 

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