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Yun Whan Kang - One of the best experts on this subject based on the ideXlab platform.

Kun Yong Chung - One of the best experts on this subject based on the ideXlab platform.

Hitoshi Jindai - One of the best experts on this subject based on the ideXlab platform.

  • Decomposition of Dichlorodifluoromethane of titania/silica
    Industrial & Engineering Chemistry Research, 1990
    Co-Authors: Seiichiro Imamura, Toshihiko Shiomi, Shingo Ishida, Kazunori Utani, Hitoshi Jindai
    Abstract:

    Catalytic decomposition of Dichlorodifluoromethane was carried out on various metal oxides. Acid catalysts such as zeolite, silica-alumina, and titatnia-silica exhibited high decomposition activities, whereas the activities of transition-metal oxides and CaO were low. Titania-silica exhibited the best performance among the acid catalysts investigated. Its acid property correlated well with its activity ; the strong acid site with a Hammett acidity parameter H 0 of less than -5.6 was effective in decomposing Dichlorodifluoromethane. Deactivation, however, occurred rapidly due to an attack of fluorine on silicon in titatnia-silica. A combination of titania-silica with CaO, which reacted with fluorine more readily than did silicon, protected the titania-silica from corrosion by fluorine, and the lifetime of this catalyst was prolonged

  • decomposition of Dichlorodifluoromethane of titania silica
    Industrial & Engineering Chemistry Research, 1990
    Co-Authors: Seiichiro Imamura, Toshihiko Shiomi, Shingo Ishida, Kazunori Utani, Hitoshi Jindai
    Abstract:

    Catalytic decomposition of Dichlorodifluoromethane was carried out on various metal oxides. Acid catalysts such as zeolite, silica-alumina, and titatnia-silica exhibited high decomposition activities, whereas the activities of transition-metal oxides and CaO were low. Titania-silica exhibited the best performance among the acid catalysts investigated. Its acid property correlated well with its activity ; the strong acid site with a Hammett acidity parameter H 0 of less than -5.6 was effective in decomposing Dichlorodifluoromethane. Deactivation, however, occurred rapidly due to an attack of fluorine on silicon in titatnia-silica. A combination of titania-silica with CaO, which reacted with fluorine more readily than did silicon, protected the titania-silica from corrosion by fluorine, and the lifetime of this catalyst was prolonged

Seiichiro Imamura - One of the best experts on this subject based on the ideXlab platform.

  • Decomposition of Dichlorodifluoromethane on phosphate group-impregnated zirconia (PO4-ZrO2) catalyst
    Industrial & Engineering Chemistry Research, 1993
    Co-Authors: Seiichiro Imamura, Kazunori Utani, Hideaki Shimizu, Toshiki Haga, Seizaburo Tsuji, Makoto Watanabe
    Abstract:

    The activity and durability of phosphate-zirconia composite catalysts were examined in the decomposition of Dichlorodifluoromethane (Freon 12). Combination of phosphate group with zirconia produced acid sites which were effective for decomposing Freon 12: 100% conversion of Freon 12 was attained at a temperature as low as 300 C on the phosphate-zirconia catalyst which had a superacid nature. The phosphate group also protected the surface of zirconia from poisoning by inorganic fluorides produced during the reaction. An addition of water helped maintain the activity of the catalyst by eliminating inorganic fluorides accumulated on its surface.

  • special articles on global and regional environment and chemistry catalytic decomposition of Dichlorodifluoromethane a study on the catalysts durable against fluorine
    Nippon Kagaku Kaishi, 1991
    Co-Authors: Seiichiro Imamura, Kenichiro Imakubo, Yoshikazu Fujimura
    Abstract:

    Catalytic decomposition of Dichlorodifluoromethane was carried out on various catalysts. Metal oxide catalysts such as CeO2 and Nb2O5 exhibited high activity; however, they were deactivated rapidly due to an attack by inorganic fluorines produced during the reaction. Although sulfuric acid impregnated on supports was also active, the vaporization of sulfur in the form of sulfur oxides lead to the deactivation of this catalyst. The BPO4 was active and retained its activity for prolonged reaction time. It was assumed that phosphate-based catalysts were the only possible system which can be applied to the decomposition of chlorofluorocarbons.

  • Decomposition of Dichlorodifluoromethane of titania/silica
    Industrial & Engineering Chemistry Research, 1990
    Co-Authors: Seiichiro Imamura, Toshihiko Shiomi, Shingo Ishida, Kazunori Utani, Hitoshi Jindai
    Abstract:

    Catalytic decomposition of Dichlorodifluoromethane was carried out on various metal oxides. Acid catalysts such as zeolite, silica-alumina, and titatnia-silica exhibited high decomposition activities, whereas the activities of transition-metal oxides and CaO were low. Titania-silica exhibited the best performance among the acid catalysts investigated. Its acid property correlated well with its activity ; the strong acid site with a Hammett acidity parameter H 0 of less than -5.6 was effective in decomposing Dichlorodifluoromethane. Deactivation, however, occurred rapidly due to an attack of fluorine on silicon in titatnia-silica. A combination of titania-silica with CaO, which reacted with fluorine more readily than did silicon, protected the titania-silica from corrosion by fluorine, and the lifetime of this catalyst was prolonged

  • decomposition of Dichlorodifluoromethane of titania silica
    Industrial & Engineering Chemistry Research, 1990
    Co-Authors: Seiichiro Imamura, Toshihiko Shiomi, Shingo Ishida, Kazunori Utani, Hitoshi Jindai
    Abstract:

    Catalytic decomposition of Dichlorodifluoromethane was carried out on various metal oxides. Acid catalysts such as zeolite, silica-alumina, and titatnia-silica exhibited high decomposition activities, whereas the activities of transition-metal oxides and CaO were low. Titania-silica exhibited the best performance among the acid catalysts investigated. Its acid property correlated well with its activity ; the strong acid site with a Hammett acidity parameter H 0 of less than -5.6 was effective in decomposing Dichlorodifluoromethane. Deactivation, however, occurred rapidly due to an attack of fluorine on silicon in titatnia-silica. A combination of titania-silica with CaO, which reacted with fluorine more readily than did silicon, protected the titania-silica from corrosion by fluorine, and the lifetime of this catalyst was prolonged

In Wook Nah - One of the best experts on this subject based on the ideXlab platform.