Manganese dioxide catalyst

Oxygen occurs free in air in which it forms 21% by volume. It is also found combined with hydrogen in water and constitutes 86% of the oceans, and with other elements such as minerals constituting ca 50% of the earth s crust. In the laboratory it is usually prepared by the thermal decomposition of potassium chlorate in the presence of manganese dioxide catalyst ... 

By the simple procedure of passing dispersed air through a suspension of ff2-diethylbenzene, 1% chromia, and 4% calcium carbonate at 130° for 40 hours, a 50% yield of m-ethylacetophenone is obtained. Likewise, aromatic esters, acetophenones, and halogenated benzenes containing alkyl groups yield the corresponding keto esters, diketones, and halo ketones, respectively. Manganese dioxide catalyst has also been used. Tetralin can be oxidized to a-tetralone with dispersed air in the absence of a catalyst (56%). ... 

Oxidation of acetylene on manganese dioxide "catalyst " External diffusion... 

A similar reaction was reported by Meth-Cohn and Suschitzky [62], who obtained aldehydes from the aerobic oxidation of amines in neutral solution in the presence of a manganese dioxide catalyst. 

Hydrogen peroxide, HaOa, is an oxidizing agent that often finds use in water purification processes. It readily decomposes to oxygen and water in the presence of a manganese dioxide catalyst (see Section 2-7). Given that the reaction is irreversible, we find that... 

Sun W, Hsu A, Chen R (2011) Palladium-coated manganese dioxide catalysts for oxygen reduction reaction in alkaline media. J Power Sources 196 4491-4498... 

II. The manganese dioxide catalysts were prepared using a newly developed ultrasonic nozzle reactor (Figure 2). The reactor behaves like a continuous stirred tank reactor. The product flows into a beaker glass of 500 ml volume. It is characterized directly without further steps of preparation by chemical reaction with a solution of hydrochloric-acid and hydrogen peroxide in water. 

Figure 2. Schematic representation of the ultrasonic nozzle reactor. The experiments to produce the manganese dioxide catalysts were carried out in this reactor...

Figure 10.5. Charge/discharge curves (a) with and (b) without the manganese dioxide catalyst (electrodes made of the same type of carbon, discharged...

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