Our previous studies have elucidated that the degradation of low density polyethylene (LDPE) in the soil proceeds synergistically by usual oxidative degradation and by enzymatic oxidative degradation. Thus it was expected that the addition of oxidizing agents which may be called as the biodegradation inducing agent, and the improvement of the accessibility of bacteria by the surface treatment of LDPE such as UV irradiation, promote the bio-degradation of LDPE. We examined the additive effect of several biodegradation inducing agents to LDPE and the degradation of the polymer in bioactive coppice soil for 12 months. Following results have been obtained: 1, The addition of vegetable oil promoted the degradation of LDPE, and the effect was more pronounced for the oxidized oil; 2, The addition of metal carboxylate such as iron stearate (II) also promoted the biodegradation; 3, UV irradiation was very effective for the bio-degradation of LDPE, and a number of hyphae which probably grew on the polymer substrate were recognized by SEM observation. The addition of a small amount of dicumyl peroxide (DCP, bis (α, α-dimethylbenzyl) peroxide) or UV irradiation was found to be very effective for the biodegradation.
The same promoting agent was compounded in ethylene-vinyl acetate copolymer (EVA). The biodegradation of EVA based sample was faster than that of LDPE based sample. We have developed the protection sheet for river dredging. The field test was carried out at Ishikari river in Hokkaido, Japan and was continued now. This is probably the first case that the bio-degradable sheet is successfully used for civil engineering.

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Aggregation states of didodecyldimethylammonium bromide (DDAB) in aqueous solution have been investigated as a function of DDAB concentration by conductivity, dynamic light scattering, spin labelling and turbidity methods. The concentration of DDAB was increased by a stepwise addition of a concentrated vesicle solution prepared by ultrasonic irradiation into water at 25 °C. It was suggested that the aggregation state of DDAB changes as follows with the increase in the concentration. ( i ) In the extremely low concentration below 0.1 mmol kg^-1, the added DDAB vesicles are completely destroyed to produce the surfactant monomer. ( ii ) In the concentration range between 0.1 and 0.7 mmol kg^-1, the vesicles are also completely destroyed, and micelles are formed, the size of which increases with the in-. crease in the concentration. ( iii ) In the concentration range between 0.7 and 1 mmol kg^-1, the destruction of the vesicles is weakened, and rather long-lived vesicles exist. (iv) In the concentration above 1mmol kg^-1, the vesicles are not destroyed and coexist with the micelles and the mononer. This characteristic concentration (1 mmol kg^-1) with respect to the vesicle destruction is regarded as a critical vesicle concentration (CVC). It was found that the CVC increased monotonically with the increase in ternperature, indicating that the DDAB vesicles are destroyed more easily at higher temperature.

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Accurate analyses of pH titration curves for iron (III) -containing solutions are not generally easy even in acidic ranges suitable to the analyses, owing to the additional complexity caused by the fact that iron (III)ion has a tendency to hydrolyze and polymerize in the solutions. In the present work, the complex formation between iron 010 and a series of aminopolycarboxylic acids and related ligands has been investigated systematically in a very wide pH range by both the pH titration and magnetic susceptibility titration methods; in the latter one developed by us, a plot of the effective magnetic moments of iron (III) against pH is called as a magnetic susceptibility titration curve and can be analyzed by a computer simulation technique. In most of the complex formation systems, it was shown that two or more binuclear iron(III)complexes or their aggregates are formed in neutral or basic solutions. In higher pH ranges precipitates were observed in some cases. It was also elucidated that more stable mono- or polynuclear complexes are formed in alkaline solutions, by a direct coordination of the deprotonated hydroxyethyl groups, which were introduced by the substitution of acetic acid residues in the ligands. An outline of this kind of complex formation in neutral and basic solutions has been first given in this study. The magnetic susceptibility titration method, which is complementary to the pH titration one, is just a powerful technique in the investigation of the present complex formation systems where the effective magnetic moment of iron (III) depends significantly on the conditions of the solutions.

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The convenient procedure for the preparation of 4, 5-dihydro-2 (3H) -thiophenethione (2) was established. It was found that the reactions of 2 with primary amines or hydrazines gave imine or hydrazones, respectively without the formation of ring opening products. The alkylation of 2 by the use of LDA and alkyl halides resulted in the formation of S-alkylated products, 2-alkylthio-4, 5-dihydrothiophenes (10).
Furthermore, it was established that the preparations of 2-alkylthio-3-alkylthiophenes by the dehydrogenation reactions of 3-alkylated 10.

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The direct photolysis of O-(p-anisoy1)-N, N-dibenzylhydroxylamine (1a) in polar and nonpolar solvents was found to give N-benzylidenebenzylamine (2a) and P-anisic acid (3a) in a 1: 1 stoichiometry without leading to anisole (4a). The results of triplet-quenching experiments show that the photolysis proceeds preferentially through the excited singlet tate. An analysis of substituent and deuterium isotope effects on the quantum yields for the reaction of la provides strong evidence that 4a is derived from decarboxylation of the anisoyloxyl radical escaped from the triplet cage but not from the singlet, and that in the latter cage hydrogen abstraction forming the elimination products 2a and 3a and recombina tion affording the starting 1a occur exclusively. On the other hand, intersystem crossing of the triplet anisoyloxyl-dibenzylaminyl radical pair intermediate was demonstrated to inherently take place in a high efficiency, based on a kinetic consideration of internal heavy-atom effects on the triplet -sensitized photolysis of 1a in acetonitrile.

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Technetium-99m is widely used in the world for the purpose of diagnosis in nuclear medicine. The ^99mTci s obtained from the parent nuclide of ⁹⁹Mo adsorbed in a generator. Synthesis of Zr-based i norganic polymer, which has extremely high adsorbability of Mo and is applicable to the ⁹⁹Mo product of low specific activity, was attempted.
Five kinds of the precur sors for Zr-based-polymer adsorbents were prepared by the hydrolysis of ZrCl₄ and the reactions between ZrCl₄ and poly (vinyl alcohol), isopropyl alcohol, ethylene glycol orglycerol. These precursors were converted into adsorbents by heating in Ar gas flow. Their structures were presumed from the pyrolysis behavior. Adsorption capacities of Mo of these adsorbents were dependent on the number of Cl atoms bonded to Zr atom in the molecules. It was suggested that the adsorption of Mo to these adsorbents was proceeded by chemical reaction between two neighboring Zr-Cl bonds and MoO₄^2-. The adsorbent prepared from ZrCl₄ and isopropyl alcohol showed the highest adsorption capacity of Mo (about 250 mg/g adsorbent) and ^99mTc yield (about 80%) in eluant.

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Discharges of wastewater containing concentrated nitrate produced in industrial plants into closed water area can promote algal blooms and water pollution with eutrophication has getting worse. Chrome yellow pigment plants are one of the industries discharging concentrated NaNO₃ wastewater.
Nitrate ions were reduced by fine Pb powder produced by continuous abrasion o f Pb plate with buff abrasive in NaNO₃ solution. Under 25-80 °C, initial concentration of NO₃^- 0.01-0.1 M, and rotation speed of buff 100-800 rpm, 20-100% nitrate ion was reduced to NO₂^-, N₂, and/or NH₃ within 12 h. Since reduction rate of NO₂^- was extremely slow, maximum percentages of formed N₂ and NH₃ were 14, 6, respectively at 12 h. Pb was oxidized at 12 h to PbO containing unreacted Pb.
In the case of producing bigger Pb particles (20 μm) by using coarse buff (#120) and increasing rotation speed, the reduction rate of NO₃^- increased due to an increase in amount of abrabed Pb and surface area of Pb by removing PbO layer grown on Pb particles. However, the reduction efficiency of Pb decreased with increasing amount of unreacted Pb core. On the other hand, producing smaller Pb particles by using fine buff (#400) and decreasing rotation speed allow the reduction efficiency to increase. Although, the reduction rate of NO₃^- was high at 1-4 h because of larger surface area of Pb produced by fine buff, it decreased gradually due to decrease in amounts of abraded Pb.

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Commercially available anthracene contains carbazole as an impurity and its removal is relatively difficult. It is known that many kinds of impurities except carbazole can be effectively eliminated from anthracene by zone melting. Therefore, the purification of anthracene can be carried out by the combination of the removal of carbazole and the zone melting. Authors have proposed a chemical method for the elimination of ppm order amounts of carbazole, using the reaction of carbazole with 9-xanthenol. After 15.0 g of anthracene containing 0.52% of carbazole and 300 mg of 9-xanthenol were dissolved in 500mL mixed solvent consisting of acetic acid, o-dichlorobenzene and concentrated hydrochloric acid (67: 30: 3), the solution has been heated at 85-87 °C for 1 h. Then, the solution has been cooled to approximately 0 °C, and the crystal of anthracene has been separated. The content of carbazole was about 120ppm and the recovery of anthracene was about 85%. This product was purified once more under the same conditions as mentioned above. The resulting product remained carbazole less than 1 ppm.

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In acetonitrile solution, efficient oxidation of 2-mercaptopyridine (PySH) to disulfide was accomplished in the presence of catalytic amount of heptylviologen (HV²⁺). The reaction gave the MichaelisMenten type kinetics, which suggests that an electron is transferred from PyS^- to HV²⁺ via the complex formation between these two species. This reaction was applied to the formation of 2-oxazolidinone derivative from carbon dioxide and _L-phenylalaninol. Contrary to the expectation, however, the reaction scarcely proceeded. This may be due to the coordination of coexisting Ph₃P to HV₂₊, which prevents the complex formation between HV²⁺ and PyS^-. When the above system was irradiated ( >370nm), however, the reaction was enhanced. The excited PyS^-* with higher reducing power probably can give an electron to HV²⁺ even in the absence of HV²⁺-PyS^- complex.

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When 1-naphthyl benzoate (1α) was boiled with anhydrous aluminum chloride (AlCl₃) in chlorobenzene, 2-benzoy1-1-naphthol (2) and 4-benzoy1-1-naphthol (3) were obtained as the rearrangement products.
A product 1-benzoy1-2-naphthol (4) was given from 2-naphthyl benzoate (1β) under the same reaction conditions.
It seems that 2 and 3 are formed via intramolecular pathway from la. Other ester lβ may proceed via both inter- and intramolecular pathways to give 4. Retro-Fries rearrangement of 2 and 3 to 1α took place in the presence of AlCl₃ in boiling chlorobenzene. The compound 4 “however” was almost recovered in the reaction of 4 with AlCl₃ in chlorobenzene at refluxed temperature.

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Photoinduced water splitting was attempted by the combination of grana, FNR and hydrogenase. A reaction mixture containing gram, NADP, FNR, NAD and hydrogenase was deaerated and was irradiated by visible light, water splitting was accomplished and both hydrogen and oxygen evolution were observed.

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The titled resin showed good adsorption ability for Bi³⁺ ion in the hydrochloric acid solution. Bi³⁺ ion is readily adsorbed on the resin as anionic chloro complexes from hydrochloric acid solution with the concentration greater than 0.1 mol dm^-3. The adsorption capacity of the titled chelating resin for Bi³⁺ ion was about 1.6 mmol per gram resin on a dry weight base. The adsorption equilibrium was attained within 5 min. Bi³⁺ ion was adsorbed effectively, passing Bi³⁺ ion solution (25 mg dm^-3) through the resin column at SV250 h^-1. Bi³⁺ chloro complex loaded on the resin can be readily eluted with 1.4 mol dm^-3nitric acid solution.

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