Partial oxidation of cyclohexane into cyclohexanone and cyclohexanol (KA-oil) is an industrially significant reaction for producing precursors for the synthesis of ε-caprolactam and adipic acid, which are the building blocks of nylon. However, to date, the cyclohexane conversion ratio has usually been limited to less than 6% to prevent further oxidation of the cyclohexanol and cyclohexanone targets. In this study, we report that Pt/CeO₂–ZrO₂–SnO₂/SiO₂, in which CeO₂–ZrO₂–SnO₂ provide reactive oxygen molecules from inside the bulk, can act as efficient catalysts. Optimization of the catalyst composition and reaction conditions provided a cyclohexane conversion ratio of 24.1% and a total selectivity for cyclohexanol and cyclohexanone of 83.4% at 130 ℃ in 0.5 MPa (4.9 atm) air for 7 h over a 5wt%Pt/16wt%Ce_0.68Zr_0.17Sn_0.15O_2.0/SiO₂ catalyst. This catalyst has significant advantages over conventional catalysts because the reaction proceeds at a lower pressure, and there is no need for toxic radical initiators or free-radical scavengers.

A Pt/CeO₂–ZrO₂–Bi₂O₃/SBA-16 (Santa Barbara Amorphous No. 16) catalyst was prepared by hydrothermal and wet impregnation methods for catalytic purification of 1,4-dioxane in water. SBA-16 has a number of mesopores and the average size of the pores is 9.4 nm. In the present catalyst, platinum and CeO₂–ZrO₂–Bi₂O₃ were successfully dispersed in the pores of the SBA-16 support, and the temperature dependence of the liquid phase oxidation of 1,4-dioxane was examined. The oxidation reaction proceeded effectively in the air atmosphere in the temperature range of 40– 80 ℃.

Novel environmentally friendly inorganic red pigments based on calcium bismuth oxide, Ca₃(Bi_1−xRE_x)₈O₁₅ (0 ≤ x ≤ 0.09; RE = Sc³⁺, Er³⁺, Y³⁺, Ho³⁺ and Dy³⁺), were successfully synthesized and the color properties were characterized. The color of these pigments depended on the composition and the synthesis condition, and the most vivid red color was obtained for the Ca₃(Bi_0.93Y_0.07)₈O₁₅ sample calcined thrice at 800 ℃ for 2 h. The L^* and a^* values corresponding to brightness and red chromaticity for this pigment were 45.6 and +30.6, respectively, which were greater than those of a commercially available Fe₂O₃ pigment (L^* = 38.4, a^* = +29.5). Since the present pigment is composed of nontoxic and safe elements, it should be an attractive alternative to the conventional Fe₂O₃ pigment.