Amalgam, aluminum sodium

Bayerite (P-Aluminum Trihydroxide). Bayerite is rarely found in nature. It has been synthesized by several methods A pure product is prepared by the Schm b method (3) in wliich amalgamated aluminum reacts with water at room temperature. Other methods include rapid precipitation from sodium alurninate solution by CO2 gassing, aging of gels produced by neutrali2ation of aluminum salts with NH OH, and rehydration of transition rlio alumina. 

The reduction of iminium salts can be achieved by a variety of methods. Some of the methods have been studied primarily on quaternary salts of aromatic bases, but the results can be extrapolated to simple iminium salts in most cases. The reagents available for reduction of iminium salts are sodium amalgam (52), sodium hydrosulfite (5i), potassium borohydride (54,55), sodium borohydride (56,57), lithium aluminum hydride (5 ), formic acid (59-63), H, and platinum oxide (47). The scope and mechanism of reduction of nitrogen heterocycles with complex metal hydrides has been recently reviewed (5,64), and will be presented here only briefly. 

Another method involves treatment with Lawesson s reagent (see 16-10). When epoxides are substrates, the products are 3-hydroxy thiols. Tertiary nitro compounds give thiols (RNO2 RSH) when treated with sulfur and sodium sulfide, followed by amalgamated aluminum. 

The only practical method for the preparation of pinacol hydrate is the reduction of acetone and the procedure described above is a modification of that of Holleman.1 The more common reducing agents that have been used are magnesium amalgam,2 aluminum amalgam,3 sodium,4 and sodium amalgam.5 Electrolytic reduction has also been used.6 1 Rec. trav. chim. 25, 206 (1906). 

Reduction of [Mo(CO)2(bpy)2] using sodium amalgam or sodium naphthalenide gives paramagnetic [Mo(CO)2(bpy)2] in dimethoxyethane (81JOM(218)C31). Oxidation of [Mo(CO)2(bpy)2] using silver tetrafluoroborate in acetonitrile or aluminum chloride in methylene chloride and followed by sodium tetrafluoroborate gives... 

Sponge Nickel Catalyst is typically used in the manufacture of amines and polyols. It is prepared by chemically treating a Nickel-aluminum amalgam with sodium hydroxide to remove... 

Sodium amalgam, aluminum amalgam, zinc, zinc amalgam, tin and iron have been added directly to solutions of the substrate in hydroxylic solvents such as ethanol, 2-propanol, -butyl alcohol, /-pentyl alcohol, acetic acid, water or aqueous mineral acid. With hydroxylic solvents, and especially with relatively acidic ones, metal amalgams are often used rather than free metals, to minimize the release of hydrogen gas as a side product. 

Hex-5-enyl-l-mercuric bromide (III) is reduced to 1-hexene (IV) by sodium amalgam, whereas sodium borohydride, lithium aluminum hydride, and tri-77-butyltin hydride gave a mixture of IV and methylcyclopentane. This is taken as evidence that sodium amalgam reduction of alkylmercury salts does not proceed via a free radical pathway [72]. 

Advances in alumina reduction technology have been surveyed [17], and alternative pathways to aluminum examined [18]. Aluminum can be obtained by metallic, carbon, or electrolytic reduction of appropriate compounds. The earliest processes successfully used metallic reduction via potassium amalgam or sodium fusion to produce aluminum from aluminum chloride (Eqs. 12.21 and 12.22). 

Silver oxide, 65, 218, 368 Silver (II) oxide, 369 Silver perchlorate, 220, 369-370 Silver tosylate, 370-371 Simmons-Smith reagent, 371-372 Sodium acetamide, 422 Sodium acetylide, 241, 398 Sodium aluminum chloride, 372 Sodium amalgam, 373 Sodium amide, 111, 158, 209, 337, 373-374, 418... 

Alkane-2,5-dione Synthesis. On treatment with n-BuLi and an acyl chloride, (1) affords an a-acylated product, which easily undergoes reductive desulfurization with aluminum amalgam or sodium amalgam. Deprotection forms an alkane-2,5-dione (eq 3). - ... 

Although reduction of ketones with alkali metals, for example, sodium (Na°) in ethanol (CH3CH2OH), to the corresponding alcohol, as already noted, has been replaced with complex hydrides, a minor product in the original reaction, the result of coupling two ketones at their respective carbonyl carbons, was occasionally found on workup of the reaction mixture. The diol (a pinacol) thus formed could be made the major product if the reaction was carried out with magnesium (Mg°) or amalgamated aluminum (Al-Hg) instead of sodium (Na°). The process, which doubtlessly involves a series of one-electron transfer reactions, is shown in Equation 9.21. 

Less satisfactory methods for preparation of the simple organotin hydrides include reduction of organotin halides with amalgamated aluminum and water (22), and the reaction of organotin sodium compounds with ammonium bromide in liquid ammonia (23, 24). 

The speed of the reaction depends both on the metal and on the alcohol, increasing as electropositivity iacreases and decreasiag with length and branching of the chain. Thus sodium reacts strongly with ethanol, but slowly with tertiary butyl alcohol. The reaction with alkaU metals is sometimes carried out ia ether, ben2ene, or xylene. Some processes use the metal amalgam or hydride iastead of the free metal. Alkaline earth metals and aluminum are often covered with an oxide film which hinders the reaction. 

Strontium [7440-24-6] Sr, is in Group 2 (IIA) of the Periodic Table, between calcium and barium. These three elements are called alkaline-earth metals because the chemical properties of the oxides fall between the hydroxides of alkaU metals, ie, sodium and potassium, and the oxides of earth metals, ie, magnesium, aluminum, and iron. Strontium was identified in the 1790s (1). The metal was first produced in 1808 in the form of a mercury amalgam. A few grams of the metal was produced in 1860—1861 by electrolysis of strontium chloride [10476-85-4]. 

Aluminum or sodium amalgam reduces 3-ones to 1,2-dihydro derivatives (71TH21500), as does borohydride (63JCS5156) and catalytic hydrogenation (Pd/SrCOs) (71TH21500). Catalytic (Pd/C) reduction of a 5-one also gave a 1,2-dihydro compound (74JMC553). 

---