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Catalytic Membrane Reactors (catalytic + membrane_reactor)
Selected AbstractsInnovative membrane based process for the selective oxidation of light alkanes assisted by the Fenton systemASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2010C. Espro Abstract Selective oxidation of light alkanes under mild conditions (temp, 80,120 °C; pressure, 140 kPa) mediated by Fe2+/H2O2 Fenton system on Nafion based composite membranes is studied in a multifunctional three phase catalytic membrane reactor (3PCMR). The role of textural properties and acid functionality on the catalytic performance of the Nafion composite membranes is outlined. The features of the multifunctional 3PCMR, enabling reaction along with product separation and recovery, are discussed. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Fabrication of multilayer ceramic membranesASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2009V.V. Zyryanov Abstract The development of multilayer mixed conducting oxide membranes on macroporous dead-end tubular composite glass/ceramic substrates is presented. Sol modification of glass/ceramic substrate enhances the performance of catalytic membrane reactor (CMR) with reduced thickness of ceramic layers. The shrinkage misfit between support and ceramic layers can be regulated by different processing steps including sol modification of substrate and preliminary annealing of ceramic powders. Nanopowders of compatible complex perovskites as membrane materials were obtained by mechanochemical synthesis. Porous and dense ceramic layers were supported onto the internal wall of substrate by slip casting of slurries comprised of the narrow fractions of agglomerated powders dispersed in organic media with addition of surfactants. For SrFeO3 -based dense perovskite ceramics, both dynamics of oxygen loss at high temperatures and mechanical properties were found to be affected by the presence of SrSO4 surface inclusions formed due to sulfur admixture in starting reactants. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] A New Generation of Catalytic Poly(vinylidene fluoride) Membranes: Coupling Plasma Treatment with Chemical Immobilization of Tungsten-Based Catalysts ,ADVANCED FUNCTIONAL MATERIALS, Issue 11 2006C. Lopez Abstract A new generation of catalytically active membranes for secondary amine oxidation and phenol degradation has been developed by coupling the advantages of low-temperature plasma-modification processes with surface chemical immobilization reactions of catalysts. Poly(vinylidene fluoride) membranes have been modified with NH3 radiofrequency glow discharges in order to graft amino groups at their surface, providing active sites for stable immobilization of tungsten-based heterogeneous catalysts. Particular attention has been focused on tungstate, WO42,, and decatungstate, W10O324,, which act efficiently as catalysts for the oxidation of secondary amines and as photocatalysts for the degradation of organic pollutants, respectively. Plasma-modified membranes surface-tailored with WO42, have been used in catalytic membrane reactors to activate hydrogen peroxide for oxidizing secondary amines to nitrones; membranes modified with W10O324, have been used for the complete degradation of phenol. The obtained results, in terms of amine,nitrone conversion and phenol degradation, respectively, appear extremely promising; these modified membranes can be considered as a pioneering, successful example of heterogenization of W-based catalysts on plasma-treated membranes. [source] Increased gas solubility in nanoliquids: Improved performance in interfacial catalytic membrane contactorsAICHE JOURNAL, Issue 2 2009Marc Pera-Titus Abstract The kinetics of gas-liquid catalytic reactions can be strongly promoted when these are performed in interfacial catalytic membrane reactors instead of other three-phase reactors such as slurry stirrers or trickle beds. The well-defined gas-liquid-catalyst contact in this system avoiding diffusional limitations is usually argued as the main reason for such enhancement. In this work, using nitrobenzene hydrogenation as a model reaction, we propose that this increased catalytic performance might also be attributed, at least partially, to increased gas solubilities in mesoconfined solvents (or simply "nanoliquids") in interfacial contactors overcoming the values predicted by Henry's Law. To support this hypothesis, we provide experimental evidence of a dramatic increase of H2 solubility in confined ethanol using mesoporous ,-Al2O3 as confining solid. Gas-liquid solubilities can be enhanced up to five times over the corresponding bulk values for nanoliquid sizes lower than 15 nm as long as the gas-liquid interface is confined in a mesoporous array. In such a situation, the volume of the gas-liquid interface is no longer negligible compared to the total volume of the confined liquid, and the high surface excess concentrations of the gas adsorbed on the liquid surface make solubility grow up dramatically. According to these measurements, we discuss how nanoliquids might form in catalytic membrane contactors, which gas-liquid configuration in the reactor appears to be more appropriate, and how the structure of the mesoporous catalytic layer contributes to their increased gas solubilization performance. © 2008 American Institute of Chemical Engineers AIChE J, 2009 [source] Catalysis in polymeric membrane reactors: the membrane roleASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2010M.G. Buonomenna Abstract Polymeric catalytic membrane reactors (PCMRs) combine a polymeric membrane that controls transfers and a catalyst that provides conversion. This review focuses on the polymeric membrane. Depending on the application, the micro-environment of the catalyst in the PCMR may be quite different from that existing in conventional reactors. This could originate different performances of the catalyst properties compared to its use without membrane. In some cases, catalysts for use in PCMR might require a specific design. In particular, the study of PCMR is a multidisciplinary activity, including material science, chemistry, and chemical engineering. Membrane based reactive separation processes, which combine two distinct functions, i.e. reaction and separation, have been around as a concept since the early stages of the membrane field itself, but have only attracted substantial technical interest during the last decade or so. Liquid phase catalytic oxidations are involved in numerous industrial processes ranging from fine to bulk chemical synthesis. PCMR polymeric membranes may also play a significant role in this field. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] | ||||||||||