New catalytic technologies in Japan

Recent trends in R&D of catalytic technology in Japan (cleaner and more efficient production, environmental catalysts, and recycling processes) are overviewed and examples of recent achievements are listed. Examples are then described as zeolite-catalyzed organic reactions recently commercialized and expected to be commercialized: hydration of cyclohexene, synthesis of pyridine derivatives and gas-phase Beckmann rearrangement of cyclohexanone oxime. Finally, as an example of environmental catalysts, the NO_x storage–reduction type three-way automobile catalyst, is introduced.     

Isolation and identification of xenobiotic aryl hydrocarbon receptor ligands in dyeing wastewater

Dyeing wastewater collected in Kyoto city, Japan, was investigated for the occurrence of aryl hydrocarbon receptor (AhR) ligands by using an AhR-responsive reporter gene assay. Concentrated extracts of wastewater samples elicited a dose-dependent increase in AhR ligand activity, and several hydrophobic HPLC fractions of the extracts were highly effective in inducing AhR ligand activity. Three potential AhR ligands were isolated from these fractions and identified to be Disperse Red 92, Disperse Yellow 64, and 3'-hydroxybenzo[b]quinophthalone by using HPLC and LC-MS/MS. Disperse Red 92, which has also been detected in the treated effluent from a sewage plant receiving the wastewater, is an anthraquinone disperse dye showing weak AhR binding affinity in the assay. Disperse Yellow 64 and 3'-hydroxybenzo[b]quinophthalone are quinoline disperse dyes capable of activating the AhR at nanomolar concentrations. In particular, Disperse Yellow 64 is a highly potent AhR ligand that was 3 times more effective in inducing AhR ligand activity than beta-naphthoflavone in the assay. Quinoline disperse dyes are suggested to be a new class of xenobiotic AhR ligands which pose a danger to aquatic biota and human health.     

Production and properties of phytase and acid phosphatase from a sake koji mold, Aspergillus oryzae

We identified three types of acid phosphatase (ACP-I, ACP-II, and ACP-III) produced by Aspergillus oryzae in a submerged culture using only phytic acid as the phosphorous substrate. The optimum pH for the activities of the three enzymes was in the range of 4.5 to 5.5. Analysis of the substrate specificities of these enzymes revealed that ACP-I and ACP-III were acid phosphatases, and ACP-II was a phytase. These enzymes were produced during different periods of mycelial growth: ACP-II was produced during the early phase of cultivation (around 24 h), and ACP-I was produced between 24 to 72 h. ACP-III was detected after the production of ACP-I and ACP-II had ceased. The release of phosphate from phytic acid was expected to be due to the cooperative hydrolysis of these enzymes.     

Modeling of CO2‐Hydrate Formation at the Gas‐Water Interface in Sand Sediment

Sub‐seabed geological storage of CO₂ in the form of gas hydrate is attractive because clathrate hydrate stably exists at low temperature and high pressure, even if a fault occurs by diastrophism like a big earthquake. For the effective design of the storage system it is necessary to model the formation of CO₂‐hydrate. Here, it is assumed that the formation of gas hydrate on the interface between gas and water consists of two stages: gas diffusion through the CO₂‐hydrate film and consequent CO₂‐hydrate formation on the interface, between film and water. Also proposed is the presence of a fresh reaction interface, which is part of the interface between the gas and aqueous phases and not covered with CO₂‐hydrate. Parameters necessary to model the hydrate formation in sand sediment are derived by comparing the results of the present numerical simulations and the measurements in the literature.     

The vibration rheometer: the effect of vibration on fresh concrete and similar materials

The use of the newly‐designed electronic accelerometer as an integral part of the vibration rheometer, for the first time made it possible to continuously and accurately record the acceleration of an apparatus piston as a solid mass oscillating in the test specimen of the material under sub‐base excitation. The research is focused on plastic concrete, mortar and appropriate reference materials whose behavior was approximated to a pseudoplastic fluid. An analytical solution to the oscillation of the piston in the specimen is also provided. The research showed that a layer of the material with the properties close to the ideal Newtonian fluid forms around each particle exceeding 0.25 mm causing a reduction in resistance to deformation and compression in a specimen. The effect of vibrations on plastic concrete and similar materials is also described.     

Protective effects of galacturonic acid-rich vinegar brewed from Japanese pear in a dextran sodium sulfate-induced acute colitis model

The effects of pear vinegar (PV), which was specially brewed for enhanced galacturonic acid content, on the DSS-induced ulcerative colitis (UC) mouse model were evaluated. PV improved clinical symptoms, colon inflammation, and histological tissue injury in the DSS-induced acute UC mouse model. Moreover, PV suppressed inflammation due to acute UC by suppressing the myeloperoxidase (MPO)-mediated activation of inflammatory cells such as leukocytes and decreasing the serum concentration of IL-6. Our results demonstrated the protective action of PV in the DSS-induced acute UC mouse model. On the other hand, commercial apple vinegar did not show a protective effect in the DSS-induced acute UC mouse model. Our findings indicate that PV may act as a new functional food for inflammatory bowel disease patients.     

Effective synthesis of ethanol from CO2 on polyfunctional composite catalysts

Synthesis of ethanol by hydrogenation of carbon dioxide has been investigated by developing the novel composite catalysts. The three different kinds of elementary reaction functions for ethanol synthesis were undertaken. The catalytic functions are partial reduction of CO₂ to CO, C–C bond formation, and –OH group insertion. For this purpose, supported Rh catalyst, Fe-based modified Fisher–Tropsch catalyst, and Cu-based modified methanol synthesis catalyst were combined by different ways. As a result, high space–time yields of ethanol as high as 0.8–0.9 kg/l h were obtained.     

Comments on the reply to comments on ‘State observers and state-feedback controllers for a class of non-linear systems’

Some further remarks seem necessary on the reply of Hauksdottir and Fenton (1990) to the present author's original comment (Birk 1990) on their paper (Hauksdottir and Fenton 1988).     

ELECTROGENERATIVE OXIDATION OF ETHANOL TO ACETALDEHYDE

Ethanol enriched vapor streams from twenty-five volume percent ethanol-water mixtures can be selectively oxidized with porous platinum electrodes and sulfuric acid electrolyte in the elec-trogeneratice mode to give acetaldehyde. Acetaldehyde yield from ethanol depends on potential and feed rate of ethanol vapor in the carrier gas stream. Control of conversions of ethanol to acetaldehyde in the range of 3 to more than 60 percent in a single stage is demonstrated. It is shown that at moderate flow rates for selective conversion there is a preferred potential range at which to operate the electrogenerative reactor.