(59d) Direct Conversion of Gasified Biomass to Long Alcohols in Solid Hybrid-Nanoparticles At the Liquid-Liquid Interface of Water/Oil Emulsions

We have developed a new reaction/separation technology based on a family of recoverable nanohybrid catalysts that simultaneously stabilize emulsions in biphasic systems[1]. These nanostructured solid particles exhibit a unique advantage in the streamlining of biomass syngas to fuels, where the presence of tars greatly complicates purification procedures.  These novel catalyst/emulsifier hybrids can catalyze reactions with high “phase-selectivity” either in the aqueous or organic phases. The amphiphilic-catalysts are obtained by fusing carbon nanotubes to metal-oxide particles, which results in a “Janus” like nanoparticle that is able to stabilize water/oil emulsions by forming a rigid film at liquid-liquid interface of the droplets, increasing the apparent viscosity of the system[2]. In the aqueous phase, the tar molecules and small oxygenates can be extracted. Upon phase migration, these species react on the inorganic oxide, which may act both as the hydrophylic side of the emulsifier and as a condensation catalyst. Hence, it is able to catalyze condensation reactions in the aqueous phase, by which small oxygenates soluble in water, with low fuel value, condense via aldol-condensation, ketonization, or etherification.  The resulting products are no longer water-soluble molecules and therefore migrate to the organic phase.  The oxide used can vary in acid/base characteristics (MgO, and SiO₂).

Ruthenium clusters were anchored onto the hydrophobic carbon nanotubes of the nanohybrids to catalyze Fischer-Tropsch reactions to produce a significant fraction of long alcohols (C5-C15).

The direct conversion of the entire gasified biomass in a biphasic liquid system could greatly simplify the processing of the syngas obtained from biomass gasification, as it does not require the conditioning of the gas prior reaction.