(111c) Carbon-Nanotubes/Metal Oxide Hybrid Catalysts As Novel Reactive-Separation System In Water-Oil Emulsions
Catalysis at water/oil interfaces in emulsions stabilized by amphiphilic nanohybrids (carbon nanostructures fused to oxides particles) has been proposed as a novel technology with promising applications, such as bio-oil upgrading and production of specialty chemicals [1,2]. Advantages of using interfacial catalysts in emulsions without surfactants include enhanced mass transfer, easier recovery of the amphiphilic catalyst nanoparticles, enhanced “phase selectivity” (i.e. selective conversion in each phase), and direct partitioning and separation of products, which leads to substantial simplification of the purification stages. Fine control of the hydrophilic/lipophilic balance of these nanohybrids allows us to systematically change type of emulsion, droplet size, and volume fraction of the emulsion . Furthermore, it is possible to control the reactions taking place in each of the phases by selectively depositing active species on the nanohybrids [1,2,4], as well as tailoring metal particle size distributions by grafting functional groups on the carbon structures . The various reactions studied in the biphasic system include aldol-condensation of oxygenates, dehydration of sugars, and hydrogenation of phenolics.
1. Crossley, S., Faria, F., Shen, M., and Resasco, D.E. Science 1, 68 (2010).
2. Ruiz, M.P., Faria, J., Shen, M., Drexler, S., Prasomsri, T., and Resasco, D.E. ChemSusChem, In press (2010).
3. Shen, M., and Resasco, D.E. Langmuir 25, 10843 (2009).
4. Faria, J., Ruiz, M.P., and Resasco, D.E. Adv. Synth. Catal. 352, 2359 (2010).