Kyoji Kaeriyama

Preparation of noble metal sols in the presence of surfactants and their properties

Abstract Stable sols of ruthenium, rhodium, palladium, platinum, silver, and gold were prepared from aqueous solutions of the corresponding noble metal salts by reduction with sodium borohydride in the presence of three different types of surfactants, stearyltrimethylammonium chloride (SC), sodium dodecylbenzenesulfonate (SD), and polyethylene glycol mono-p-nonylphenyl ether (PN). The size of colloidal particles in these sols differs from one another according to the type of surfactant. The cationic surfactant, SC, gave positively charged sols, while either the anionic one, SD, or neutral one, PN, gave negatively charged sols. Surfactants also had considerable effects on the stabilities of sols toward electrolytes.

Structure and properties of polythiophene derivatives

Abstract Soluble and conducting poly(3-methoxythiophene) (poly-MOT) and poly(3-methylthiothiophene) (poly-MTT) films were prepared by the electrochemical polymerization of the corresponding monomers. The doped polymers were soluble in propylene carbonate (PC), dimethyl sulfoxide (DMSO), and 1-methyl-2-pyrrolidinone (NMP). Cast films could be obtained from their solutions. The degrees of polymerization of poly-MOT and poly-MTT were 79 and 7.4, respectively. The visible-near i.r. spectra of either polymer solution had characteristic peaks due to bipolarons. The doped poly-MOT was stable in air, due to its low oxidation potential. Poly-MOT was also prepared by the oxidative coupling of MOT with FeCl 3 . The conductivity of a poly(3-phenylthiophene) (poly-PT) film was 140 S/cm. Its cyclic voltammograms showed well-defined waves corresponding to cation-doping as well as anion-doping. Spectral changes during electrochemical reduction indicate that cation-doping really took place. At low levels of anion-doping, an unambiguous peak associated with transition between two polaron bands was observed. Poly(3-methylpyrrole) (poly-MPY) films were electrochemically prepared and their properties were compared with those of polypyrrole (poly-PY). The condutivity of a poly-MPY film was 220 S/cm, two orders of magnitude higher than the reported value, and its oxidation potential was lower than poly-PY, suggesting that polypyrroles having higher alkyl groups might be soluble conducting polymers and stable in doped states.

Coal liquefaction by colloidal iron sulphide catalyst

Abstract Taiheiyo coal, which was treated with an aqueous solution of dodecyltrimethylammonium chloride, adsorbed colloidal iron sulphide prepared from FeS0 4 · 7H 2 O and Na 2 S · 9H 2 O in aqueous media. The adsorbed colloidal iron sulphide was much more effective as a catalyst for the liquefaction of the coal itself than the usual powder-type iron sulphide. Thus in differential thermal analysis under hydrogen, the coal with 0.35wt% adsorbed colloidal iron sulphide gave an exothermic peak at 401 °C, which was ≈20 °C lower than when using the powder-type iron sulphide. The coal was smoothly hydrogenated at 450 °C to give a yield of ≈60% liquid products.