Fumio Nozaki

Structure of the Supported Uranium Oxide Catalytic and Catalytic Activity for Oxidation of Carbon Monoxidet

In order to reveal the catalytic properties of uranium oxide-alumina and uranium oxidesilica, various investigations on the structure of catalyst and the activity for catalytic oxidation of CO were performed.The experimental results gave the following conclusions.(1). As shown in Fig.3, the oxidative activity of the catalyst supported on silica is remarkably low, comparing with the catalyst supported on alumina. This is due mainly to the fact that uranyl compound used as a starting material for the catalyst preparation hardly decomposes to uranium oxide, contrasting with the case in which uranyl compound is supported on alumina.(2) The reaction rates of CO oxidation by the catalyst supported on alumina or the catalyst without carrier can be expressed approximately as the first order with CO pressure and the zeroth order with 02 pressure. Apparent activation energy is nearly equal to be 25 kcal/mol for the former catalyst and 18 kcal/mol for the latter catalyst.(3) The following reaction scheme has been postulated, U308 + CO A > U307 + CO, (catalyst reduction step)U307 + 1/2 02 --+ U808 (catalyst oxidation step)i. e., the reaction proceeds by oxidation-reduction cycles, in which the catalyst reduction step is the rate-determining process.(4) Generally speaking, alumina and silica trend to combine with uranium oxide or uranyl compound during the course of catalyst preparation. The catalysts calcined up to 500°C contains various chemical species of uranium, the catalytic activity levels of which are different. At present it was evident that the active components were limited only to uranium oxide on alumina and uranium oxide-alumina compound.

Structure of Uranium-Antimony Oxide Catalyst and Catalytic Activity for Oxidation of Propylene to Acrolein

In order to reveal the catalytic properties of uranium oxide-alumina and uranium oxidesilica, various investigations on the structure of catalyst and the activity for catalytic oxidation of CO were performed.The experimental results gave the following conclusions.(1). As shown in Fig.3, the oxidative activity of the catalyst supported on silica is remarkably low, comparing with the catalyst supported on alumina. This is due mainly to the fact that uranyl compound used as a starting material for the catalyst preparation hardly decomposes to uranium oxide, contrasting with the case in which uranyl compound is supported on alumina.(2) The reaction rates of CO oxidation by the catalyst supported on alumina or the catalyst without carrier can be expressed approximately as the first order with CO pressure and the zeroth order with 02 pressure. Apparent activation energy is nearly equal to be 25 kcal/mol for the former catalyst and 18 kcal/mol for the latter catalyst.(3) The following reaction scheme has been postulated, U308 + CO A > U307 + CO, (catalyst reduction step)U307 + 1/2 02 --+ U808 (catalyst oxidation step)i. e., the reaction proceeds by oxidation-reduction cycles, in which the catalyst reduction step is the rate-determining process.(4) Generally speaking, alumina and silica trend to combine with uranium oxide or uranyl compound during the course of catalyst preparation. The catalysts calcined up to 500°C contains various chemical species of uranium, the catalytic activity levels of which are different. At present it was evident that the active components were limited only to uranium oxide on alumina and uranium oxide-alumina compound.

EFFECTS OF EMULSIFIERS AND OXYGEN ON THE EMULSION GRAFTING OF STYRENE ONTO PRE-IRRADIATED RAYON.

電子線で空気中前照射処理したポリノジックレーヨンへのスチレン乳化グラフト重合において乳化剤の種類およびその添加量,そして酸素量の反応成績におよぼす影響を検討した。その結果,つぎの諸点が明らかになった。一般的に陰イオンおよび非イオン性活性剤がよく,陽イオン活性剤は本反応系において乳化剤として適格でない。また,乳化剤の添加量とともにグラフト率およびグラフト効率ともに低下するのが一般であった。酸素の影響として,本報告の乳化グラフト法はメタノールを溶媒とする溶液グラフト法にくらべて酸素の抑制効果が見かけ上小さい。また,乳化剤の種類によってこの抑制効果が相違し,陰イオン性活性剤を使用するとこれをきわだって小さく保ち得た。