Manganese preparation

Different primary, secondary aryl or heteroaryl manganese bromides 519 were prepared by reaction of activated manganese [prepared form manganese dichloride, lithium and a catalytic amount (15%) of 2-phenylpyridine as electron carrier, in THF] with the corresponding brominated compounds 516. These intermediates react with different electrophiles in THF at 0°C with or without copper chloride, to yield the corresponding products 20 (Scheme 144). ... 

After dipping strips of zinc into concentrated solutions of manganese salts, they scraped off a deposit containing zinc, lead, cadmium, nickel, and cobalt. After complete removal of these heavy metals by precipitation as the sulfides, they found no evidence of element 43, but thought they found the X-ray lines of number 75 ( 42). When Dr. Druce took his dwi-manganese preparation to the Charles University in Prague for polaro-graphic examination, the Czechoslovakian chemists confirmed his conclusions. 

In the atmospheric pressure synthesis of hydrocarbons from hydrogen and carbon monoxide. Elvins32 showed experimentally that reduced un-suoported catalysts of cobalt, copper, or manganese prepared by ignition of the nitrates gave much greater conversions than the reduced precipitated oxides. 

Manganese prepared imder the same conditions but deposited on an imcooled surface, e.g., an alumina rod, is less reactive. The dense, silvery scales of the crystalline metal are easily stripped off and reduced to powder. This product is the a -modification, which is stable at temperatures below 742°C. 

Griffin PJ, Fogarty WM Physicochemical properties of native, zinc-prepared and manganese-prepared metalloprotease of Bacillus polymyxa. Appl Microbiol 1973,260) 191-195. 

Various aromatic aldehydes were reacted with the active manganese prepared from using manganese chloride. Table 8.24 reports that simple treatment of aryl aldehydes with active manganese gives the corresponding 1,2-diols in moderate to good isolated yields under very mild conditions, rt in THF. The results are shown in Table 8.24. 

On the industrial scale oxygen is obtained by the fractional distillation of air. A common laboratory method for the preparation of oxygen is by the decomposition of hydrogen peroxide. H Oj, a reaction catalysed by manganese(IV) oxide ... 

In the laboratory, bromine is prepared by oxidation of bromide ion the oxidation is carried out by mixing solid potassium bromide with manganese(IV) oxide and distilling with concentrated sulphuric acid ... 

Iodine is rarely prepared in the laboratory the method used is the oxidation of an iodide by manganese(IV) oxide and sulphuric acid, for example with sodium iodide ... 

Manganese(IV) oxide is the only familiar example of this oxidation state. It occurs naturally as pyrolusite, but can be prepared in an anhydrous form by strong heating of manganese(II) nitrate ... 

However the Mn (aq) ion can be stabilised by using acid solutions or by complex formation it can be prepared by electrolytic oxidation of manganese(II) solutions. The alum CaMn(S04)2.12H2O contains... 

In the laboratory it can be prepared by the electrolysis of water or by heating potassium chlorate with manganese dioxide as a catalyst. 

Manganese(II) can be titrated directly to Mn(III) using hexacyanoferrate(III) as the oxidant. Alternatively, Mn(III), prepared by oxidation of the Mn(II)-EDTA complex with lead dioxide, can be determined by titration with standard iron(II) sulfate. 

Acetaldehyde [75-07-0] (ethanal), CH CHO, was first prepared by Scheele ia 1774, by the action of manganese dioxide [1313-13-9] and sulfuric acid [7664-93-9] on ethanol [64-17-5]. The stmcture of acetaldehyde was estabhshed in 1835 by Liebig from a pure sample prepared by oxidising ethyl alcohol with chromic acid. Liebig named the compound "aldehyde" from the Latin words translated as al(cohol) dehyd(rogenated). The formation of acetaldehyde by the addition of water [7732-18-5] to acetylene [74-86-2] was observed by Kutscherow] in 1881. 

Synthetic manganese carbonate is made from a water-soluble Mn (IT) salt, usually the sulfate, by precipitation with an alkafl or ammonium carbonate. The desired degree of product purity determines the quaUty of manganese sulfate and the form of carbonate to be used. For electronic-grade material, where the content of K O and Na20 cannot exceed 0.1% each, the MnSO is specially prepared from manganese metal, and ammonium bicarbonate is used (26) (see Electronic materials). After precipitation, the MnCO is filtered, washed free of excess carbonate, and then, to avoid undesirable oxidation by O2, dried carefljlly at a maximum temperature of 120°C. 

Manganese Nitrate. Manganese nitrate [10377-66-9] is prepared from manganese(II) oxide or carbonate using dilute nitric acid, or from Mn02 and amixture of nitrous and nitric acids. Mn(N02)2 exists as the anhydrous salt [10377-66-9]-, the monohydrate [3228-81-9]-, ttihydrate [55802-19-2],... 

Manganese Hydroxide. Manganese hydroxide [18933-05-6] is a weaMy amphoteric base having low solubihty in water. Mn(OH)2 crystals are reported to be almost pure white and darken on exposure to air. Manganese dihydroxide occurs in nature as the mineral pyrochroite and can also be prepared synthetically by reaction of manganese chloride and potassium hydroxide that is scmpulously free of oxygen. The entire reaction is conducted under reducing conditions (36). 

Mn2(H2P202)2) is the stable product in the potentiometric deterrnination of manganese. Manganese(III) does not coordinate with amines or nitro complexes, but it does make manganicyanides of the types M2(Mn(CN)g) and M2(Mn(CN) (OH)), which are similar to the ferricyanides. The K", Na", LC and manganicyanides have been prepared and slowly hydroly2e in water to MnO(OH). 

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