SILP Catalysis with Supercritical Flow

This synthesis of cyclic carbonates was also carried out with the IL grafted to silica [48], to a polymer support [49], or to molecular sieves [50], all using CO2 as solvent and reagent but not in its supercritical state. 

The outcome of the experiments showed higher rates than biphasic and commercial hydroformylation reactions. The substrate flow rate was found to be the main factor affecting the reaction, giving higher conversions at lower flow rates. Furthermore, the system was stable for over 40 h with a very low catalyst leaching 

The reaction was carried over 65 h. Full conversion to product was achieved continuously, with no signs of catalyst leaching above the detection level of 1 ppm. During the first 10 h of reaction, the enantioselectivity was 99% ee, which 

I 18 Supported Ionic Liquid Phase Catalysts udth Supercritical Fluid Flow 

Grubbs-Hoveyda catalyst evaporated on to silica can be used for metathesis, but only with nonpolar substrates and products [59]. More polar flowing chemicals cause extensive leaching. 

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It must be also noted that supported ionic liquid phase (SILP) catalysis can also be successfully combined with supercritical fluids. Cole-Hamilton et al. [127] have reported recently high activity (rates up to 800 h ), stable performances (>40 h) and minimum rhodium leaching (0.5 ppm) in the hydroformylation of 1-octene using a system that involves flowing the substrate, reacting gases and products dissolved in... 

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