Silver permanganate catalyst

Diols are prepared from alkenes by oxidation with reagents such as osmium tetroxide, potassium permanganate, or hydrogen peroxide (Section 11-7C). However, ethylene glycol is made on a commercial scale from oxacy-clopropane, which in turn is made by air oxidation of ethene at high temperatures over a silver oxide catalyst (Section 11-7D). 

Fig. 3. Variation of log e (escaping concentration)-1 with breakdown time for various silver permanganate-metallic oxide catalysts (a) zinc oxide carrier (b) miscellaneous oxide carriers.

The first step in the GC determination of carbon and hydrogen is quantitative oxidation of the sample organic compounds, usually with a catalyst. Copper oxide is commonly used, but the reaction is relatively slow and elevated temperatures of about 900°C are required. With silver permanganate the reaction temperature is reduced to 550°C [34, 35] and with cobalt oxide to 750°C [36, 37] both compounds provide a shorter oxidation time. Other catalytic oxidizing agents, such as nickel oxide [38, 39] and cerium(IV) oxide [40], have been found promising. Platinum can also be used, especially when it is necessary to avoid the retention of any oxidation products by the solid catalyst. 

Oxygen is used with catalysts such as copper oxide, mixed oxides of cobalt and silver permanganate. Different techniques are used to separate water from carbon dioxide. 

Chromium oxide (Cr203). Up to 0.1% colorimetrically with diphenylcarbizide at 540 nm. Above 0.1% but as a minor constituent, colorimetrically with EDTA at 550 nm. As a major constituent by oxidation to dichromate by peroxodisulfuric acid using a silver nitrate catalyst, destruction of permanganate with HCl and titration against ferrous ammonium sulfate using diphenylamine-4-sulfonate indicator. 

In aqueous solution, manganous salts are oxidised to manganese dioxide,6 and if silver nitrate is present as catalyst, to permanganate 0 the latter change constitutes Marshall s reaction. Chromium solutions in a similar manner give rise to chromate,7 even without a catalyst. Ferrous and cerous salts are converted into ferric and ceric salts, respectively, and phosphites are oxidised to phosphates. 

Several, different, electrochemical oxidations of 26 to 27 have been reported. Using a variety of electrodes (copper, Monel metal, nickel, or silver), 26 was oxidized in aqueous potassium hydroxide solution containing potassium chromate or potassium permanganate, to afford 27 in 70-85% yield.118,119 This electrochemical oxidation has been conducted in aqueous, alkaline solution in the presence of a surfactant, but with added metal catalyst, to give 27 in 85-95% yield.120 Alternatively, the oxidation has been performed by using an anode on which nickel oxide was deposited. This anode, in a solution of 26 at pH >9, with or without nickel salts, afforded 27 in >90% yield.121 A number of additional publications described122-140 other modifications of the... 

Ammonium or potassium peroxodisulphate Solid (NH4)2S208 or K2S208 is added to a dilute solution of manganese(II) ions, free of chloride. The solution is acidified with dilute sulphuric acid, and a few drops of dilute silver nitrate (which acts as a catalyst) are added on boiling a reddish-violet solution is formed, owing to the presence of permanganate ... 

Mn(II) can be oxidized quantitatively to permanganate in perchloric acid by the use of silver ion as a catalyst. In the presence of phosphate, Ce(III) is oxidized to Ce(lV) phosphate, which precipitates from a solution containing sulfuric and phosphoric acids. The precipitate can be dissolved in sulfuric acid. Other oxidations that can be performed quantitatively are V(IV) to V(V) in acid solution, hypophosphite and phosphite to phosphate, selenite to selenate, tellurite to tellurate, nitrite to nitrate, and in alkaline solution, iodide to periodate. 

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