Reduction of organometallic compounds by hydrosilanes (H_nSiR_4-n) is studied. Because the H-Si bond in hydrosilanes shows reactivity similar to the H-H bond and, in addition to this feature, the Si part may display Lewis acidic property to activate oxygen-containing functional groups, it is expected that hydrosilanes can reduce oxygen-containing intermediates. As a result of our study, successful reproduction of elementary steps of catalytic CO hydrogenation (e. g. the carbon-chain propagation step of the Pichler-Schulz mechanism, methanation via the Fischer-Tropsch mechanism) is realized on discrete transition metal complexes.

View full abstract

New mechanism for oxygen activation in biological oxygenases has been proposed; in the present proposal the substrate is assumed to play an important role to activate the oxygen (or peroxide derivative) through donating electron to it, and several experimental facts to support the new idea have been provided This idea suggests that formation of a high-valent iron-oxo species in cytochrome P-450 occurs only when the iron (III) -peroxide intermediate is activated through electronic interaction with substrate and also with the peripheral organic group, the latter of which also acts as an electron donor.

View full abstract

We present the results of a paper chromatographic study of the effect of electrolyte on the mechanism by which oily soils are removed with surfactant from a substrate in a state almost without mechanical and/or hydrodynamic actions from the standpoint of surface chemistry. Using a cellulose filter paper as the stationary phase for the substrate, R_f' values of oleic acid (OA), squalene (SQ) or cholesterol (CH) as a model of sebum soil have been examined as a function of sodium dodecyl sulfate (SDS) concentration in aqueous solution containing NaCl. An increase in the concentration of SDS produced an increase in the R_f' value of the oily soils to give a higher detergency. When NaCl was added, alower SDS concentration was required to increase the R_f' values in order to produce the removal of the oily soils at a lower SDS concentration. Based on a filter paper capillary analysis, it was suggested that the removal of OA from cellulose fiber occurred due to a molecular complex formation between OA and SDS at a low concentration below the critical micelle concentration (cmc) of SDS. The number of SDS molecules bound to OA decreased with increasing concentration of NaCl. At a concentration above the cmc, the dete rgency of OA could be explained on the basis of the solubilization of the soil. The addition of NaCl to the SDS solution above the cmc produced an increase in the partition coefficient of OA between the fiber and SDS micelle, and a decrease in the partition coefficient of OA between the micelle and water, to give a lower detergency of the OA.

View full abstract

A liquid chromatography technique using a column packed with fiber powders has been introduced for the study of detergency from a physicochemical view point of surfactants involved when oily soils are removed from a fiber substrate into a queous detergent solution in a state almost without mechan ical and /or hydrodynamic actions. The retention volumes of two oily soil models (CI Solvent Yellow 5 and CI Solvent Yellow 14) on two stationary phases (polyester and cellulose) have been measured as a function of the aqueous sodium dodecyl sulfate (SDS) micelle concentration in the mobile phase. The partition coefficients of two soil models between the fiber substrate and micelles (P_sm), between the fiber substrate and water (P_sw) and between micelles and water (P_mw) were determined with the application of the partition equation for the pseudophase liquid chromatography to this system. The P_sm, and P_sw values were larger for the polyester system than for cellulose w hich showed that oily soil is much more difficult to remove from polyester than from cellulose. It produced a tendency similar to the effects of fiber substrates on oily soil removal and on oily soil redeposition that have been studied using radiotagging and other methods. This liquid chromatography technique may be used to investigate the equilibrium beh avior during soil removal and for the soil redeposition on a substrate in a detergent solution.

View full abstract

This paper describes the synthesis of pure calcium ferrite monosulfate hydrate (abbr. CFMSH), the thermal decomposition process of CFMSH, the rehydration of its intermediates thermally treated at various temperatures and the reconstruction of initial layer structure. These results obtained are compared with results of literatures on hydrotalcite.
To remove CaSO₄·2H₂O being contained as mixture in CFMSH specimen obtained at optimum compounding molar ratios (CaO/Fe₂(SO₄)₃) of 7.0, decarbonated water warmed to 40 °C was used. Synthesis of pure phase CFMSH was identified by XRD and FT-IR. The results obtained by thermal analysis, XRD and FT-IR showed the following. The host layer structure of pure CFMSH obtained in this way was destroyed by heating until 400 °C. At ca. 610 °C, 2CaO. Fe₂O₃, CaO and CaSO₄ (type II) were crystallized. The thermal decomposition of CaSO₄ occurred at ca. 1200 °C releasing SO₃. All rehydration products of intermediates thermally treated under 1200 °C s howed roentgenographically the same layer crystal structure as initial CFMSH. Therefore, it was found that the temperature range of reconst ruction of CFMSH by rehydration method was more wide than that of hydrotalcite. On the other hand, the XRD result of rehydration product of i ntermediate thermally treated at 1400 °C did not show the initial layer structure, but showed the presence of Ca₃Fe₂(OH)₁₂ of cubic system and Ca(OH)_2.

View full abstract

The Michael type addition of thiols to α, β-unsaturated esters such as methyl acrylate in benzene is very slow in the absence of catalysts. In contrast, the reactions in the presence of alumina proceeded easily under mild conditions to give the corresponding adducts in high yield. However, in the reaction with 2-methyl-2-butenoic acid (tiglic acid) esters under similar conditions, the yields of the adducts were very low. When the reaction with tiglic acid esters was carried out without solvent, the adducts were obtained in high yields. In the addition of o-aminothiophenol, the mercapto group added to α, β-unsaturated esters predominantly, and the reaction with dimethyl maleate gave the corresponding benzothiazine derivative in high yield under mild conditions.

View full abstract

Poly (methyl methacrylate) (PMMA) films containing three kinds of typical π-conjugated organic dyes, a nitrone dye, a styryl dye, and an azobenzene dye, are irradiated by Xe lamp. Their photobleaching characteristics are investigated and applications for optical polymer waveguides are discussed. For a few microns-thick films fabricated by spin-coating, following three characteristics are experimented; (1) changes of UV-VIS absorption, IR absorption and film thickness caused by photobleaching, (2) thermal reversibility of photobleached film, (3) refractive index changes induced by photobleaching.
From the practical point for optical polymer waveguide fabrication, following three features are required; (1) photobleaching does not proceed under weak UV light with fluorescent light level, (2) the dye structure does not show thermal reversibility after photobleaching, and (3) enough refractive index difference for optical waveguides should be induced by photobleaching.
Among three dyes, investigated, PMMA film containing azobenzene dye is revealed to be the best one for fabricating dye containing optical polymer waveguides and bis-azobenzene dye attached PMMA film will be the most promising for the waveguides via photobleaching.

View full abstract

It is necessary for super-water-repellent surface to show low surface energy and to construct microrough structure on the surface. This report is for super-water-repellent surface that can be made by coating a paint that consisting of a fluorine-containing compound and two kinds of SiO₂ filler.
We examined solubility of the fluorine-containing compound using various ratio of mixed solvents. The effect of filler concentration and the profile of the surface on the super-water-repellent were studied.
Using a suitable ratio of mixed solvent, the fluorine-containing compound was localized on the surface. In addition to the fillers in the solvents, micro-rough structure was made on the surface. Using the paint containing more than 4.0 wt% of filler, the surface showed super-water-repellency. Atomic Force Microscopy analysis showed that super-water-repellent surface had higher fractal demension than non-super-water-repellent surface.

View full abstract

The kinetics of the ligand substitution reaction between the ethylenediamine-N, N'-bis[2- (2-hydroxyphenyl) acetato]-cadmate (II) ion and the ethylenediaminetetraacetatoferrate (III) ion were carried out at 25 °C and ionic strength = 0.1 mol dm^-3. The substitution reaction was shown to proceed by a chain reaction mechanism where the chain propagating steps are the reactions of metal complexes with metal ions. The properties of the metal chain reaction mechanism are discussed. The metal-substitution of [Fe (edta) ]^- with cadmium ion was studied by the use of the chain reactions. The observed rate consta nts of the reaction were separated into two rate constants. The mechamism of the reactions is discussed.

View full abstract

An isocyanate-terminated prepolymer prepared from 1, 1'-methylenebis (4-isocyanatobenzene)(MDI) and α-hydro-ω-hydroxypoly (oxytetramethylene) (PTMG) was chain extended with 2, 2bis (hydroxymethyl) propionic acid (DMPA). The resulting carboxy group-containing polyurethane was converted into a polyurethane anionomer by treatment with potassium acetate, magnesium acetate, or N, N'-dimethylpiperazine. The chemical structure of the polyurethane anionomer was characterized with respect to its mechanical, dynamic viscoelastic and thermal properties.

View full abstract