Novel thermal latent hardeners containing blocked carboxyl groups with alkyl vinyl ethers i.e. hemiacetal esters, have been developed. They showed liquid form or lower melting point and excellent solubility and compatibility. Although the blocked carboxyl groups were stable under usual condition, they could regenerate the corresponding free carboxyl groups by thermal dissociation of hemiacetal ester. A novel crosslinking system between blocked carboxyl group and epoxide was examined. The new one-package thermosetting coatings provided by the system have been applied to practical automotive and coil coatings line production. The formed coatings have high level of acid resistance, corrosion resistance and weatherability with reduction of VOCs.

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A relationship between acid-base properties on ZrO₂ catalysts prepared by hydrolysis of ZrOCl₂ adjusted to various pH values with NH₃ solution and their crystalline structures determined by XRD measurements was examined.
When the hydrolysis was carried out at pH7 and pH3, followed by the calcination at low temperature of 723K in air, it was confirmed that the obtained ZrO₂ had a simple structure of monoclinic and tetragonal, respectively.
The acid and base amounts per unit surface area of the ZrO₂ were scarcely different in the type of the crystalline structures, indicating that the densities of acid and base sites present on the surfaces were not affected by the crystalline structures. However, the strength of both acid and base sites was found to significantly depend on the crystalline structures. The strong acid and base sites were observed in TPD spectra of NH₃ and CO₂ to appear on the monoclinic ZrO₂ obtained by the calcination at low temperature, while only weak acid and base sites were observed on the tetragonal ZrO₂ surface as well as on the monoclinic ZrO₂ calcined at high temperatures. The higher specific activity and the lower activation energy for 1-butene isomerization were observed on monoclinic ZrO₂ catalysts. It is suggested that the strong acid and base sites are formed on monoclinic ZrO₂ with small particle size, and this is due to the structural defect.

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Ab initio MO Calculation was performed to study the solvent effect for S_N2 type nucleophilic oxirane ring opening of aflatoxin B₁8, 9-oxide by using model compounds, (2S, 3R, 3aR, 6aS)-3a, 6a-dihydrofuro[2, 3-b]furan 2, 3-oxide (I) and (2R, 3S, 3aR, 6aS)-3a, 6a-dihydrofuro[2, 3-b]furan 2, 3-oxide(II). H₂O molecules were considered for the solvation to oxirane oxygen, on which negative charge grows as the reaction proceeds. Stationary points including transition structures(TSs) were optimized with no geometrical constraint at the RHF/3-21G basis set. Relative energies were evaluated at Becke3LYP/3-21G level based on the RHF/3-21G geometries.
Calculation clarified the following points:
(1) Although H₂O molecules can coordinate to oxirane oxygen without steric congestion for the reaction of I, II suffers severe steric repulsion between coordinating H₂O molecules and the fused dihydrofuran moiety. On the basis of the model study, experimentally observed higher reactivity of exo isomer of AFB₁ oxide than endo for nucleophilic reactions can be explained by the difference of solvent effect between them.
(2) For the reaction of II, coordination of H₂O molecules to oxirane oxygen is limited to occur from only three directions(outside, backside, and inside). Judging from the energetics of single and two H₂O coordinating systems, coordinating capability of H₂O to oxirane oxygen(that is, stabilizing ability of TS) is in the order of outside>backside>inside coordination, implying that the steric repulsion between H₂O and AFB₁ unit is in the order of outside<backside<inside.
(3) The energy difference between the most stable exo- and endo-attacking TS tends to increase as the number of coordinating H₂O(n value) increases, clearly suggesting that solvent effect makes endo-oxirane(I) much more reactive for nucleophilic ring opening reaction.
(4) In the reaction of I, the activation energies drastically became small as the number of coordinating H₂O to oxirane oxygen increases. On the other hand, in the reaction of II activation energy for three-H₂O coordinating system became larger than that for two H₂O coordinating system, which is attributable to the steric congestion between B ring and solvating H₂O to oxirane oxygen.

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6-Amino-4-aryl-2H-1, 3, 5-thiadiazine-2-thiones 6 were obtained by the reaction of N-cyanobenzamidines 5 with carbon disulfide in the presence of potassium hydroxide at -5°C via N-(N-cyanobenzimidoyl)imidodithiocarbonate. Whereas alkali degradation of aliphatic amidines such as N-cyanoformamidine or N-cyanoacetamidine gave no desired compounds under similar conditions. Treatment of 6 with alkali or acid produced 1, 3, 5-triazines or N-benzoylthiourea derivatives, respectively. The reaction of 6 with primary or secondary amines in DMF smoothly proceeded to give N¹-substituted N²-thiocarbamoylbenzamidines 19. Considering the structures of products given by reactions of 6 with some nucleophiles, it was found that an amidino part of 6 was the most reactive site and nucleophiles attacked at 4-position of 1, 3, 5-thiadiazine ring. Treatment of 6 with methyl iodide in the presence of base gave 2, 4-bis(methylthio)-1, 3, 5-triazines 21 at -5°C.

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The ceramization process of poly(Si-isocyanato-Si-methylpolysilazane)(MPZ-6) was investigated by means of the ceramic yield on pyrolysis, carbon content analysis, and solid-state cross-polarization/magic angle spinning nuclear magnetic resonance (CP/MAS NMR) spectra. On the pyrolysis of MPZ-6 under ammonia atmosphere, isocyanato and methyl groups were eliminated at about 400°C to provide silicon nitride oxide at 700°C. The ²⁹Si, ¹³C, and ¹⁵N CP/MAS NMR spectra showed disappearance of the signals due to silylmethyl and silylisocyanato groups and appearance of the signals due to nitride oxide SiN_4-nO_n(n=0-4) unit structures, when the pyrolysis temperature was raised. In addition, the S/N ratio decreased in the ¹³C CP/MAS NMR spectra, due to the elimination of carbon on heating. MPZ-6 was amorphous after the pyrolysis at 1400°C.

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From the view of amphiphilic structure of urushiol molecules as main components in lacquer tree paint, the effect of addition of amphiphilic compounds to the lacquer tree paint on the curing process and the light resistance was investigated to find the relationship between the curing reaction of lacquer tree paint and the molecular structures of the amphiphiles as additives. Lacquer tree paint films were added amphiphiles such as 2-hydroxy-4-alkoxybenzophenone bearing alkyl group with different chain lengths, poly(oxyethylene) octadecyl ether with different oxyethylene unit numbers, suger ester and light stabilizer having long alkyl groups, cured and photo-irradiated.
When the chain length of alkyl groups in the benzophenone derivatives is close to that in urushiol molecules, the curing reaction was little inhibited. Surfactants with larger poly(oxyethylene) units exhibited more profound inhibition of curing reaction. Amphiphiles used as additives in the present study were not observed to promote the formation of reverse micelles in lacquer tree paint, but they were compatible with the reverse micelle structure.

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Studies were conducted on the adsorption rates of samarium by a macromolecular sorbent impregnated with 2-ethylhexyl hydrogen-2-ethylhexylphosphonate(2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester, EHPNA, HR) using a stirred transfer cell.
The initial adsorption rate of samarium N₀ decreased as hydrogen ion concentration [H⁺] increases at [H⁺]>0.1mol m^-3, and the hydrogen ion concentration dependence of adsorption rate becomes nearly zero at [H⁺]≤0.1mol m^-3. The initial adsorption rate of samarium increased with increasing EHPNA content in the sorbent[¯H¯R], and decreased with increasing samarium concentration[Sm]₀^T.
The inner particle capacity coefficient k_sa_v calculated from overall capacity coefficient K_sa_v and outer particle capacity coefficient k_Fa_v were proportional to the 2nd power of EHPNA content in the sorbent, and were proportional inversely to the 2nd power of samarium concentration and to the 1st power of hydrogen ion concentration at [H⁺]≤4mol m^-3.
The ratio of mass transport resistance of samarium 1/k_sa_v against the overall mass transport resistance 1/K_sa_v lowered remarkably with increasing pH and EHPNA content in the sorbent.

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To make clear trend and chemical components formation mechanism of aerosol in urban area, aerosol sampling and experiment was carried out at 5 sites in Tokyo for 5 years.
Sampling was for 24 hours(72 hours at mountain site) once a month from May 1993 to March 1997, by using high volume air sampler.
TSP concentration was measured by weigh method and sampling solution extracted from TSP was analyzed to obtain pH, EC, cations and anions.
Variation of TSP concentration was changed larger after November 1995 than before at several sites.
TSP concentration in urban area is 2.4 times higher than in mountain area, while [H⁺] concentration in suburb and mountain area were higher tendency than in urban area.
EC value was high correlative with amount of several ions concentration. It is appeared that counter ion to retain H⁺ cation is corresponded to SO₄^2- anion, because of retaining experiment with quartz filter and high correlation between H⁺ and SO₄^2-.
Moreover, [SO₄^2-] concentration in urban area is higher than in mountain area, it was inferable that H₂SO₄ concentration before neutralization was also high level in urban area.

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