Manganese dioxide activity

Econocat A process for deodorizing gases by catalytic oxidation over manganese dioxide activated with other metals. Developed and sold by Cortaulds Engineering. 

Manganese Dioxide (active grade) Amines, inorganic Bases, HjO, Tuads Meta-dinitro-benzene Stearic acid, isostearic acid MnO, (active grade) provides polysuifide compositions with heat resistance. Amount recommended per 100 parts of polysulfide polymer 7.5... 

Yuan, A., and Q. Zhang. 2006. A novel hybrid manganese dioxide/activated carbon supercapacitor using lithium hydroxide electrolyte. Electrochemistry Communications 8 1173-1178. 

Ultrasonication (s.a. Manganese dioxide, activated ultrasonically Yeast, ultrasonically stimulated)... 

Matsuda Y, Yamashita K, Takasu Y. Characteristics of manganese dioxide-active carbon as an oxygen electrode in alkaline-lype fuel cells. Electrochemistry 1983 51 925-30. 

Open-Circuit (No-Load) Voltage The open-circuit voltage in this battery is dependent on the manganese dioxide activity and the system pH. The cathode slurry is adjusted to a constant pH to minimize battery to battery voltage variation. For example, the P-80 battery is adjusted so the voltage is 6.40 V at 56 days and 6.30 V after 12 months of shelf storage. 

Even ia 1960 a catalytic route was considered the answer to the pollution problem and the by-product sulfate, but nearly ten years elapsed before a process was developed that could be used commercially. Some of the eadier attempts iacluded hydrolysis of acrylonitrile on a sulfonic acid ion-exchange resia (69). Manganese dioxide showed some catalytic activity (70), and copper ions present ia two different valence states were described as catalyticaHy active (71), but copper metal by itself was not active. A variety of catalysts, such as Umshibara or I Jllmann copper and nickel, were used for the hydrolysis of aromatic nitriles, but aUphatic nitriles did not react usiag these catalysts (72). Beginning ia 1971 a series of patents were issued to The Dow Chemical Company (73) describiag the use of copper metal catalysis. Full-scale production was achieved the same year. A solution of acrylonitrile ia water was passed over a fixed bed of copper catalyst at 85°C, which produced a solution of acrylamide ia water with very high conversions and selectivities to acrylamide. 

Cathode Reaction. There are many different types of manganese dioxide (18), having varying activity in batteries. The only type suitable for alkaline batteries is y-Mn02, the mineral form of which is nsutite. The chemical composition of has been described (19) by the general formula... 

If the solution is allowed to flow through a granular bed such as sand, the larger particulate matter remains on the surface, while the smaller material is collected in the thickness of the granular bed. Pressurization of the filter accelerates the process. Besides sand, other materials used as filtering media are anthracites, manganese dioxide, and activated carbon. 

Hydroxyandrosta-4,6-dien-3-one. A suspension of 42 g of crude androsta-4,6-diene-3j ,17j -diol in 2000 ml of chloroform is treated with 250 g of activated, manganese dioxide. The mixture is then shaken vigorously for 15 min in a stoppered flask. The mixture is filtered and the manganese dioxide washed well with chloroform in order to elute material which initially remains adsorbed on the solid phase. The filtrate is concentrated to a pale yellow, crystalline residue. Recrystallization from acetonitrile gives 38 g (90%) of 17/ -hydroxyandrosta-4,6-dien-3-one as plates mp 211-214°. 

A highly active form of manganese dioxide is available from Beacon Chemical Industries, Inc., 33 Richdale Ave., Cambridge, Mass. 02140. 

Nickel peroxide is a solid, insoluble oxidant prepared by reaction of nickel (II) salts with hypochlorite or ozone in aqueous alkaline solution. This reagent when used in nonpolar medium is similar to, but more reactive than, activated manganese dioxide in selectively oxidizing allylic or acetylenic alcohols. It also reacts rapidly with amines, phenols, hydrazones and sulfides so that selective oxidation of allylic alcohols in the presence of these functionalities may not be possible. In basic media the oxidizing power of nickel peroxide is increased and saturated primary alcohols can be oxidized directly to carboxylic acids. In the presence of ammonia at —20°, primary allylic alcohols give amides while at elevated temperatures nitriles are formed. At elevated temperatures efficient cleavage of a-glycols, a-ketols... 

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