Manganese dioxide gel

A magnetic study of dehydration in manganese dioxide gel has been made in the writer s laboratory. This is parallel to that described above for chromia gel. As in Table III, the dehydration indicated was cumulative. The expected loss of oxygen occurred after long dehydration. The analytical results are, therefore, more conveniently expressed in terms of a formula. (See Table IV.)... 

Pang SC, Anderson MA, Chapman TW. Novel Electrode Materials for Thin-Film Ultracapacitors Comparison of Electrochemical properties of Sol-Gel Derived and Electrodeposited Manganese Dioxide. J. Electrochem. Soc. 2000 147(2) 444-50. 

Silica reinforced rubber, 22 703 Silica sheets, 22 383-385 Silica-silane system, 22 377-378 Silica sol-gel fiber processing, 23 80 Silica sols, 22 383, 473-474 applications of, 22 394 modification of, 22 393-394 preparation of, 22 392-393 properties of, 22 391-392 purification of, 22 393 Silica, solubility in steam, 23 212-213 Silica-supported activated manganese dioxide, 76 568... 

Quantitative methods of obtaining protactinium start from the carbonate precipitate from the treatment of the acid extract of certain uranium ores. After this carbonate precipitate is dissolved, the protactinium remains 111 the silica gel residue, from the solution of which it is obtained on a manganese dioxide carrier. An alternate method effects final separation... 

Ya.B. considered that the most important adsorbents—porous coal, silica gel, and the powdered manganese dioxide which he had studied experimentally—are amorphous substances, i.e., they do not have clearly articulated crystalline structure. Only thus is it possible to obtain a large developed surface—the most important feature of an adsorbent. In this case, it is natural to consider all the possible values of adsorption activity and a smooth distribution function of surface sectors according to their level of activity. 

Keywords sulfide, manganese dioxide, FESCVsilica gel, sulfoxide... 

Keywords alcohol, manganese dioxide, silica gel, microwave irradiation, ketone, aldehyde... 

The time required to achieve complete reaction varies from 20-48 hr depending on the activity of the manganese dioxide. The progress of the oxidation is easily monitored by TLC analysis on silica gel. 

Methods of oxidation of hydrazo to azo compounds and hydroxylamino to nitroso compounds have been reviewed. Reagents which oxidize aromatic primary amines to azo compounds are also suitable for the oxidation of aromatic hydrazo compounds, since the hydrazo compounds are intermediates in the oxidation of the amines. Thus, manganese dioxide, mercury(II) oxide and lead tetraacetate are all suitable oxidants. Silver carbonate on Celite rapidly oxidizes both diarylhydrazines and acylhydrazines to the corresponding azo compounds in good yield. Another supported oxidant which can convert hy-drazobenzene into azobenzene in high yield is sodium periodate on silica gel. ... 

Like tertiary amines, tertiary phosphines are readily transformed into the corresponding oxides, phosphine oxides. Tributylphosphine in di-chloromethane is oxidized with ozone adsorbed on silica gel at -70 "C to tributylphosphine oxide in 92% yield [113]. Other oxidants used to transform phosphines into phosphine oxides are potassium peroxysulfate [205], argentic oxide [381 ], manganese dioxide [813], and barium manganate [S55] (equation 537). 

With the help of metal catalysis amidation takes place at room temperature under apparently neutral conditions. Manganese dioxide in large quantities, or, even better, manganese dioxide on silica gel, is well suited to this conversion. Even compounds with functional groups labile to manganese dioxide, for example benzylic groups, are suited for the hydration. With pentacarlwnylmanganese bromide, nitrile hydration takes place under PTC conditions. ... 

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