Phase-transfer catalysis, thermoregulate

Jin Z, Zheng X (1996) Thermoregulated Phase-transfer Catalysis. In CornUs B, Hermann WA (eds) Aqueous-Phase Organometallic Catalysis, Chap. 4, Sect. 6.3. Wiley, Weinheim, p 233... 

Fig.1 The general concept of thermoregulated phase-transfer catalysis (TRPTC)...

Thermoregulated Phase Transfer Catalysis - A conceptual advance in the field of biphasic hydroformylation of higher olefins is the use of rhodium catalysts generated from nonionic tenside phosphines, such as ethoxylated tris(4-... 

Thermoregulated Phase-transfer and Thermoregulated Phase-separable Catalysis... 

Thermoregulated Phase-transfer Catalysis with Nonionic Water-soluble Phosphines... 

Thermoregulated phase-transfer catalysis, however, could be successfully put into effect for the hydroformylation of higher olefins in aqueous/organic two-phase media [11], As shown in Table 2, various olefins have been converted to the corresponding aldehydes in the presence of nonionic phosphine-modified rhodium complexes as catalysts. An average turnover frequency (TOF) of 250 h-1 for 1-do-decene and 470 Ir1 for styrene have been achieved. Even the hydroformylation of oleyl alcohol, an extremely hydrophobic internal olefin, would give a yield of 72% aldehyde [19]. In comparison, no reaction occurred if Rh/TPPTS complex was used as the catalyst under the same conditions. 

The principle of thermoregulated phase-transfer catalysis (TRPTC), originally developed by Bergbreiter et al. [12], which has been applied to two-phase hydro-formylation by Fell, Jin and co-workers [13], which is based on a temperature-controlled switch of the catalyst system from the aqueous phase to the organic phase (see Section 4.6.3). 

Two novel methodologies termed assymmetric phase transfer catalysis and thermoregulated phase transfer catalysis have been developed readily in the past decade and have broadened greatly the scope of application of PTC. Therefore, it is worthwhile briefly discussing these two techniques. 

FIG. 8 Thermoregulated phase transfer catalysis hydroformylation of higher olefins (Cg-C ). 

Recently, a new aqueous biphasic catalytic system based on the cloud point of nonionic tensioactive phosphine, termed thermoregulated phase-transfer catalysis (TRPTC) has been developed [13]. The concept ofTRPTC as a missing link could not only provide a meaningful solution to the problem of catalyst/product separation, but also extricate itself from the limitation of low reaction rates of water-immiscible substrates. 

Thermoregulated Ligands and Thermoregulated Phase-Transfer Catalysis... 

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