(196c) Hydrophobization of Catalyst Surfaces for Reactions in Biphasic Systems

Reactive-separation processes using solid nanoparticles with amphiphilic character and catalytic activity are investigated.  These systems combine the advantages of phase transfer and heterogeneous catalysis with increased interfacial area, enhanced rate of mass transfer between the two phases, effective separation of products from the reaction mixture by differences in the water/oil solubility, and catalyst stability. We are investigating the fundamental phenomena involved in the catalysis at liquid-solid-liquid interfaces and its application in biomass upgrading (upgrading of pyrolysis oil and sugars), Fischer-Tropsch synthesis, and enhanced oil recovery.  By anchoring metal catalysts selectively on either the hydrophobic or the hydrophilic side of the amphiphilic particles it has been possible to selectively convert compounds, which are primarily present in one of the phases, i.e. “phase-selectivity”. Interestingly, when the hydrophobization of the catalyst is extended to the entire surface the resulting catalyst exhibits enhanced stability in aqueous environments, while preserving the same emulsification properties. Consequently, hydrophobization of microporous zeolites and metal-oxides catalysts has been successfully employed in the upgrading of bio-fuels in biphasic liquid systems, in which the use of conventional zeolites or metal-oxide catalysts is hindered by fast rates of deactivation due to dissolution into the bulk aqueous phase.