Reduction zinc-magnesium

Metallothermic reductions, aluminum-magnesium and zinc-magnesium... 

Electrowinning of metals in aqueous solutions is applicable to those metals that possess high electrochemical reduction potentials, such as silver, copper, cadmium, and zinc. Magnesium, aluminum, and sodium, like other reactive metals, are electro-produced from molten salt baths, such as NaCl/CaCh mixture at ca. 600 °C for sodium and MgCl2/NaCl/CaCl2 eutectic mixture at ca. 750 °C for magnesium. 

The popularity of the Nef reaction is due in part to the ready availability of nitro compounds. Primary and secondary halides react with sodium nitrite in dimeAyl sulfoxide (DMSO) or dimethylform-amide (DMF) to give useful yields of nitro compounds. Primary amines can be oxidized to nitro compounds with potassium permanganate, m-chloroperbenzoic acitP or ozone. Chlorination of oximes with hypochlorous acid and reduction with magnesium, zinc or hydrogen/lpalladium gives secondary nitro compounds. Stabilized carbanions can be nitrated by treauitent with a nitrate ester, and enol acetates are nitrated by acetyl nitrate to give nitro ketones. ... 

Other methods are similarly based on the reduction of molybdic acid for example, by means of zinc, magnesium, or sulphur dioxide, the resulting solution then being titrated with standard potassium per-... 

Reduction of the triphenylcyclopropenium cation with zinc, magnesium and chromium salts, or by electrolysis affords hexaphenyl 3,3 -bicyclopropenyl via the triphenylcyclopro-penyl radical With lithium aluminium hydride the triarylcyclopropenium ions are reduced to the corresponding triarylcyclopropene. 

Uranium, plutonium, and the remaining FP-3 elements are separated from the FP-4 elements and the donor alloy by a second salt transport process using a MgCl2-MgF2 salt. The Cu-Mg reduction alloy is the donor alloy. A zinc-magnesium alloy is the acceptor alloy. 

Earlier laboratory processes used to prepare metallic protactinium include vacuum decomposition of the oxide by 35-keV electrons [G6] and thermal decomposition of the pentahalides [G2]. More recently, protactinium has been prepared by reducing the tetrafluoride by barium vapor [CS, S3, Zl], by calcium at 1250°C [M2] and by zinc-magnesium. The purest protactinium has been prepared by reduction in a barium-fluoride crucible at 1300°C [L2]. 

Corey-Winter olefin synthesis (1, 1233-1234 2,439-441 3,315-316 4, 269-270, 541-542 5,34, 661). Vedejs and Wu converted thionocarbonates into olefins by alkylation with methyl iodide (90°, DME, sealed tube) followed by reduction (zinc dust—ethanol or magnesium amalgam—THF). This two-step procedure was used for preparation of the cyclobutene (2) in this case the reaction with triethyl phosphite was immeasurably slow. 

The metals commonly employed in these reductions include the alkali metals, calcium, zinc, magnesium, tin and iron. The alkali metals are often used in solution in liquid ammonia or as suspensions in inert solvents such as ether or toluene, frequently with addition of an alcohol or water to act as a proton source. Many reductions are also effected by direct addition of sodium, or particularly, zinc or tin to a solution of the compound being reduced in a hydroxylic solvent, such as ethanol, acetic acid or an aqueous mineral acid. 

Garg, S. P. (1970). Reduction of zirconium oxide with zinc-magnesium alloys in molten flux media. Trans. Indian Inst. Met., 23( ), 37-42. 

Using a zinc-magnesium mixture,55 di(cyanoethyl)tetralone undergoes a reductive annelation (Eq. 16). 

Salts of metals such as zinc, magnesium, manganese, and nickel, which form insoluble hydroxides, especially at cathodic areas, which are more alkaline due to the hydroxyl ions produced by reduction of oxygen... 

The text mentions that scandium metal is obtained from its molten chloride by electrolysis, and that titanium is obtained from its chloride by reduction with magnesium. Why are these metals not obtained by the reduction of their oxides with carbon (coke), as are metals such as zinc and iron ... 

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