Thermoregulated Inverse Phase-Transfer Catalysts

Indeed, high activity was obtained in the biphasic hydroformylation of higher olefins in the presence of Rh/PETPP complexes as catalysts, which demonstrated that the water solubility of the substrate did not influence the effectiveness of the TRPTC system. Some TRPT catalysts such as PETPPs 17, P-N bidentate (PEDPA 

PEDPSA N,N-dipolyoxyethylene-substituted-4-(diphenylphosphino)benzenesulfonamide, OPGPP octylpolyglycol-phenylene-phosphite. 

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The thermoregulated phase-transfer function of nonionic phosphines has been proved by means of the aqueous-phase hydrogenation of sodium cinnamate in the presence of Rh/6 (N =32, R = n-CsHu) complex as the catalyst [16]. As outlined in Figure 2, an unusual inversely temperature-dependent catalytic behavior has been observed. Such an anti-Arrhenius kinetic behavior could only be attributed to the loss of catalytic activity of the rhodium complex when it precipitates from the aqueous phase on heating to its cloud point. Moreover, the reactivity of the catalyst could be restored since the phase separation process is reversible on cooling to a temperature lower than the cloud point. 

The thermoregulated phase-transfer function of TRLs has been proven by means of the aqueous-phase hydrogenation of sodium cirmamate in the presence of an Rh/AEOPP complex as the catalyst [18]. As outlined in Figure 3, an tmusual inversely temperature-dependent catalytic behavior has been observed. 

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