In order to investigate the redox reactions of metal complexes in the ion exchanger, the reductive-elution behavior of chloro Fe ( III ) -complexes adsorbed in an anion-exchanger from hydrochloric acid solution to non-adsorptive Fe ( II ) was examined by using Sn( II ) and V( III ) as reducing agents. The currentpotential curves of Fe ( III ) /Fe ( II ) in hydrochloric acid solutions of concentrations ranging from 0.1 to 9.0 mol dm-3 were measured by the cyclic voltammetry and the effects of chloro-complexes formation on the redox potential were examined. The adsorption-elution experiments were carried out using both batch and column method, and the effects of reductants as well as hydrochloric acid concentration on the elution behavior were discussed.
The redox potential of Fe ( III) / Fe( II ) decreased with increasing hydrochloric acid concentration, revealing that the reduction of Fe ( III ) to Fe ( II ) becomes difficult due to the formation of chloro-complexes. The Fe ( III ) adsorbed in the ion-exchanger was reduced and eluted rapidly by Sn, while the reductive-elution was very slow by using V ( III ). This is considered to result from the difference in the adsorbability of the reductants, and the experimental results suggested that the redox reaction between Fe ( III ) and Sn (II) occurred mainly in the ion-exchanger phase and that between Fe ( III ) and V ( III )happened in the solution phase.

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The kinetic mechanism of CO-N₂O reaction was compared on two MgO surfaces hydrated (Shy) and dehydrated (Sde), e mploying infrared spectroscopy, the transient response method and a computer sim ulation technique. The linear CO species and the formate-originated CO gas were found to react with N₂O while carbonate species did not show any reactivity. The reaction orders of CO₂ and N₂ formations in CO-N₂O reaction were first with respect to CO and zero-th with respect to N₂O on both the surfaces, suggesting that the main route of the reaction was between CO g as and adsorbed oxygen spec ies. The transient responses of CO₂ and N₂ formed by t he step changes of CO concentration in CO-N₂O mixture, on the other hand, showed the difference of kinetic mechanism for the two samples, in which an instantaneous mode on Shy and an overshoot mode on Sde were observed. The computer simulating analyses of these response curves suggested that the most slow step on Shy was the surface reaction between gaseous CO and adsorbed oxygen species, while the activation of adsorbed oxygen including electron transfer process on Sde. The rate constant of this activation step on Shy was larger than that on Sde by two orders, and the result was explained by the contribution of the surface hydroxyl on Shy to this activation step of surface oxygen. This surface hydroxyl worked as the electron donor of surface oxyge n species and therefore facilitated regeneration of the active oxygen species involved in CO-N₂O reaction.

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Colorless and transparent crystals of NaGdSiO₄ were grown from an NaF flux by a slow cooling method. The solubility of NaGdSiO₄ in NaF increased with increasing temperature. At 1100°C, NaGdSiO₄ was dissolved in NaF at a concentration of about 0.87 mol%. The eutectic temperature was 990±5°C. The flux growth was conducted by heating mixtures at 1100 °C for 10 h, followed by cooling to 600°C at a rate of 5°C h^-1. The mixture containing 0.25 mol% solute produced only needle crystals. The mixtures containing 0.5 and 0.75 mol% solute gave needle and prismatic crystals. Needle, prismatic and bulky crystals were grown from the mixtures containing 1-5 mol% solute. When the mixtures contained more than 6 mol% solute, only bulky crystals were grown. The maximum sizes of the needle, prismatic and bulky crystals were 3.6 mm×0.2 mm, 3.2 mm×0.6 mm and 2.3 mm×1.2 mm, respectively. The most suitable solute content was 0.75 mol% for the growth of needle crystals. In the case of the growth of prismatic and bulky crystals, the most suitable solute content was 1 mol%. The grown crystals belonged to the tetragonal system and the lattice parameters observed were a= 11.743±0.001Å and c= 5.443±0.001Å. The basic form of grown crystals was an eight-sided prism with pyramidal end faces. The indices of all the faces were {100}, {110} and {121}. The EPMA data showed that sodium, gadolinium, silicon and oxygen were distributed almost homogeniously in the crystals. The density was 4.82±0.02 gcm^-3.

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The rearrangement of cinnamyloxybenzene in diethylene glycol gave, in addition to 2- and 4-cinnamylphenols, diethylene glycol monocinnamyl ether. The formation of the ether is ascribed to the acidic and high dielectric properties of the glycol solvent that allows to generate and capture the cinnamyl cationic intermediate.

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ThegagproteinhydrolysismechanismbyHIV-1proteaseusingthePM-3semiempiricalmolecular orbitalmethodwasstudied. Firstofa11, thepotentialenergyminimizationwasperformedontheenzymesubstratecomplexofHIV-1protease, whichwasconstructedfromtheenzymestructuredeterminedbyXraycrystallography.Theoptimizedstructurerevealedthathydrogenbondsamongawater moleculeandapairofasparticacidresiduesholdthewatermoleculeattheactivesiteandthatthewater moleculestronglyinteractswiththecarbonylcarbonatomoftyrosineatthecleavagesiteofthe substrate. Next, themodelcompoundforquantumchemicalcalculationswasconstructedfromthis optimizedEScomplexstructure. Thelowestpotentialenergyreactionpathfollowingthehydrolysis reactionoftheTyr-PropeptidebondbyHIV-1proteasewasdeterminedbythePM-3method. The mechanismelucidatedinthisresearchconsistsofthe6stepsoftheelementaryreaction.Therate-deter miningstepwastheprocessoftheOH-generationfromH₂O.Andtheactivationenegyofthisprocess was18.9kcal/mol. ThisresultstronglysuggeststhatgagproteinhydrolysisbyHIV-1proteaseoccurs ln vivo.

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Synthesis of 1, 3-cyclohexadiene through liquid phase dehydration of 2-cyclohexen-l-ol in aqueous solution was examined using zeolite and ion-exchange resin catalysts with various reaction methods. As the results, significant improvement has been achieved for the problem of by-production of dicyclohexenyl ether and activity deterioration, which was the problem found in one-liquid phase system of 2- cyclohexen-1-ol reported previously.
Two-liquid phase reaction system involving oil-and-water two phase gave a good 1, 3-cyclohexadiene yield of 50% or higher with H-ZSM-5 and Amberlist-15, but H-Y, H-β, and H-mordenite gave only extremely low yield of the same level as obtained in one-liquid phase system. It was suggested that hydrophobicity of highly silicious zeolite was required for catalytic activity to appear in the aqueous reaction system, based on the comparison with hydrophobicity determined by adsorption method of aqueous solution of 1-propanol. The separation speed of oil/water in two-liquid phase system was compared with that of cyclohexene hydration system. It was found that the separation speed of two-liquid phase system was slower by an order of magnitude than the latter and furthermore decreased with time.
The reaction system which uses homogeneous dilute aqueous solution of 2-cyclohexen-1-ol was th en examined. In this system, the by-production of dicyclohexenyl ether was suppressed through equilibrium, and only little amounts of its formation was observed. Comparison in the activity between H-ZSM-5 and Amberlist-15 revealed that H-ZSM-5 exhibited higher activity than Amberlist-15.
By using a reaction system which uses the combination of homogeneous dilute aqueous solution a nd reactive distillation with slurry of H-ZSM-5, 1, 3-cyclohexadiene was obtained at the yield of nearly 90%. No catalyst deactivation was observed for 80 h. It is considered that quick removal of formed 1, 3cyclohexadiene from the reaction system as the minimum azeotropic mixture with water results in the suppression of deterioration due to polymer formation, which should lead to the high yield.

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The addition of flux and the grind of calcined powders in the synthesis of barium ferrite for use in magnetic recording have been examined to improve the reaction efficiency. In this study, barium chloride was entirely used as the flux. In the absence of the flux, the synthesis reaction of barium ferrite was practically completed at 1130°C and for 70 min, but the coercive force of the product did not fit the Cybernetics standard. In the presence of barium chloride in a range between 1.9 and 2.9%, however, the synthesis reaction reached near completion (97.1%) and the coercive force of the product (2510-2620 0e)fitted the Cybernetics standard. Furthermore, the coercive force of the samples, which had been below the Cybernetics standard at the calcination stage, was much improved by grinding the calcined powders with a planetary ball mill, and the distribution of coercive force, i. e., SFD (switching field distribution)were successfully kept down to the level required for practical use.

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The processes of degradation of stainless steel SUS316 and Al-Si-ceramics contacted with ozone were investigated in the aqueous solution (about 20 ppm 03) and in the humid gas environment (about 4.5 vol% 03). The experiments were carried out at room temperature. The changes of surface of these samples were evaluated by SEM, EDX and Auger electron spectroscopy. The ICP technique was used to measure kinetics of ion elution from solid samples into aqueous solution containing ozone. For the stainless steel, it was determined that in ozone gas atmosphere the corrosion film (Fe0OH, CrO, Cr, M oSi2) was produced and it was easily destroyed by 03, and while in the aqueous solution of ozone the weight loss was 0.014% aftenten days sintering. The amounts of the individual Fe, Cr and Ni-ion eluted f rom the steel were also measured. For two kind of Al-Si-ceramics, the corrosion rates in ozone gas environment were negligible slow. But, in the aqueous solution of ozone, amounts of dissolved Al and Si-ions were increased gradually during 35 days. The weight loss of sample Si28 (28 wt% Si02) and sample Si60 (60 wt% Si02) were 0.096% and 0.02%, respectively. It was assumed that the dissolved chemical species were aluminate and silicate ions such as A102-, A1033-, SiO32-, SiO44-

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Colorless and transparent crystals of CaKPO₄ were grown for the first time from a K₂MoO₄ flux by a slow cooling method. Flux growth of CaKPO₄ crystals was conducted by heating mixtures containing 2to 20 mol% solute at 1100°C for 10 h, followed by cooling to 500°C at a rate of 5°C h^-1. CaKPO₄ crystals of sizes up to 0.5 mm x 0.5 mm×0.1 mm were grown. The crystal sizes were dependent on the solute content. The most suitable content was 4 mol%. The shape of the crystals was a hexagonal thin plate. On the basis of X-ray diffraction and differential thermal analysis studies, it was shown that the grown crystals could exist in two polymorphic forms. The stable form at room temperature transformed into high-temperature form (hexagonal) at about 660°C. The most developed crystal faces of the hightemperature form had an index of [0001].

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Adsorption-desorption phenomena of pyridine at a mercury electrode were studied by a flow injection method with mesuring differential capacity-time curves.
At more positive potentials than -0.9 V the adso rbed pyridine molecules are never desorbed, which means that the adsorption is irreversible. At -1.35 V a very sharp desorption peak is observed, which means that the adsorption is reversible. Irreversibly adsorped pyridine molecules replace water molecules at the surface of the electrode. Reversibly adsorbed pyridine molecules, which form groups of molecules, are placed on the water molecules at the surface of the electrode. When the groups of pyridine moleculs are desorbed, very large peaks are observed.

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An aqueous solution of a commercial liquid synthetic detergent (1 vol%) for kitchen use was photodecomposed in the presence of TiO₂ powder under an atmosphere of air at room temperature. The concentration of the detergent decreased to about one-half of its initial value at illumination times of 6 h. The yield of gaseous products decreased in the order of CO₂>C₂H₄>H₂. Illumination for 6 h decreased the concentration of oxygen to about one-third of the initial value.

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