Liquid-liquid and liquid-gas reactions using solid catalysts are often encountered in the chemical process industry, most frequently in hydroprocessing operations and in the oxidation of liquid phase organic. Along this line, we have attempted to make an effective heterogeneous catalytic system for these applications. Recently, a novel concept of "phase-boundary catalysis (PBC)” in order to utilize the immiscible liquid-liquid reaction system with solid catalysts was proposed (see Fig. 1) [1-4]. In the PBC system, it was demonstrated that the bimodal amphiphilic zeolite particles, NaY zeolite loaded with alkylsilane-covered titanium oxide, could be placed at the liquid-liquid phase boundary between aqueous hydrogen peroxide and water-immiscible organic phases and act as efficient catalyst for epoxidation reaction without any mechanical agitation. NaY zeolite was found to be more effective than nonporous silica counterpart as “Phase-boundary catalyst” to promote the epoxidation of alkenes with aqueous 30% H2O2.
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