A microwave (MW)-assisted method for the continuous production of hydrogen from methylcyclohexane using platinum on spherical carbon beads has been developed, and its application to the efficient dehydrogenative aromatization of fully saturated cyclic alkanes, including piperidines as representative heterocycles, has been studied. Effective dehydrogenation was achieved by the construction of a highly intense energy field, which acted as a reactive site, on the irradiation of the carbon beads (CB) support. The reaction could be carried out with only 10-W single-frequency MWs. The catalyst system could be used continuously for at least 12 h without any loss of catalyst activity. Dehydrogenative aromatization could also be catalyzed and simple cyclohexane derivatives, as well as piperidine derivatives as representative N-heterocyclic alkanes, were tested.

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A practical and efficient method for scavenging palladium leached into the reaction mixture using thiol-modified dual-pore silica beads has been developed. Reducing the level of metal contamination, especially palladium, in pharmaceutical and bioactive compounds and fine chemicals to below the regulatory value is quite important for the quality assurance of industrial products. We have evaluated the performance of dual-pore silica beads as a palladium scavenger by investigating their ability to eliminate the divalent palladium ions in dilute palladium­(II) acetate in methanol (5 and 50 ppm) and ethyl acetate (5 ppm) solutions. The ability of the dual-pore silica beads to eliminate the palladium species leached from a 10% palladium on carbon (Pd/C) catalyst during the ligand- and copper-free 10% Pd/C-catalyzed Sonogashira-type coupling reaction was also investigated. The thiol-modified dual-pore silica beads exhibit a more rapid and effective elimination ability toward leached palladium species in the reaction mixture in comparison with commercially available conventional thiol-modified silica scavengers because of the effects of diffusion and perfusion due to the dual-pore skeleton of the silica beads. When methanol is used as a dilution and eluent solvent for the filtered reaction mixture, the leached palladium species were removed almost entirely (<1 ppm).

We developed a microwave-mediated continuous hydrogen production method from 2-PrOH using platinum on a spherical carbon-bead catalyst. The catalyst cartridge consisted of helical glass part, and straight glass part (helix−straight cartridge) was newly developed for the effective microwave heating of 2-PrOH in the presence of 5% Pt/CB. The microwave resonance was properly adjusted within 2.4−2.5 GHz using the helix−straight cartridge with the glass resonance-adjuster tube. The reaction was conducted by the irradiation of only 10 W of single-frequency microwaves and the catalyst was used continuously for at least 13 h without any loss of catalyst activity.

As a fundamental investigation of the separation and recovery of rare earth metals from an aqueous solution, the extraction characteristics of lanthanum and cerium have been studied by using microcapsules containing a metal extractant. As the extractant, 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (EHPNA), was used. The extractant was successfully encapsulated in microcapsules during the in situ microencapsulation process. The extractabilities of the metals into the microcapsules were determined from the extraction isotherms of the metal ions.From the Langmuir model, the saturation amount of metal extracted and the extraction equilibrium constants were determined. The metal extraction rates were also measured using the microcapsules containing EHPNA. As a result, it was shown that the overall extraction process of the metals was controlled by a chelating complex formation reaction between the metal and EHPNA.