Metal hydrides sodium hydride

M-H (metal hydride) Sodium hydride Potassium hydride Strong, not nucleophilic base Deprotonation of weak organic acids with acidities as high as pKa 25... 

Metal hydrides Sodium hydride, lithium tiluminum hydride... 

In the fine chemical industry, reduction of carbonyl groups mainly relies on the use of complex metal hydrides sodium dihydrobis-(2-methoxyethoxy)-aluminate, commercialized as RedAl or Vitride is one of the most used (4). 

Metal hydrides Calcium hydride, lithium aluminum hydride, sodium borohydride... 

Another general method of preparation involves the reaction of cyclopentadiene with sodium metal or sodium hydride in tetrahydrofuran (THF). Addition of iron(ll) chloride to this solution forms the complex dicyclopenta-dienyliron ... 

Metal hydrides. Lithium hydride, sodium hydride, potassium hydride and lithium aluminium hydride all react violently with water liberating hydrogen the heat of reaction may cause explosive ignition. Excess metal hydride from a reaction must be destroyed by the careful addition of ethyl acetate or acetone. 

In aqueous solution, SO2 is reduced to dithionite by a range of metals or sodium hydride. With metal halides, SO2 forms complexes and may behave as an electron donor (e.g. with AICI3, SnBr4, or TiCU) or undergo solvolysis (equation 16)... 

Deamination of C-(trialkylamine)carbaundecaborane(12) derivatives to the carborane anion BjoHiaCH" can be accomplished with sodium metal or sodium hydride in tetrahydrofuran solution. A procedure using sodium metal is described here to illustrate this general reaction. The properties of the cesium and tetramethylammonium salts of the BioHi2CH anion are given. 

Use For chemical reactions where advantages of controlled reaction rate, lower reaction temperature, increased yields, or substitution for more expensive reagent can be achieved, as in, removal of sulfur from hydrocarbons and petroleum, metal powders, sodium hydride, alcohol-free alcoholates, phenylso-dium. 

Nickel oxide electrodes constitute the positive plates of several storage systems (among which nickel-zinc, nickel cadmium, nickel metal-hydride, sodium-nickel chloride) [16]. In recent years, the high-specific energy and specific power of Ni-Zn systems has increased the interest in their use for electric vehicles with respect to the past years, when their application was essentially limited by a short cycle life. 

The alkoxide ion (RO ) for the Williamson ether synthesis is prepared by using sodium metal or sodium hydride (NaH) to remove a proton from an alcohol. 

Metal Hydrides. Metal hydrides can sometimes be used to prepare amines by reduction of various functional groups, but they are seldom the preferred method. Most metal hydrides do not reduce nitro compounds at all (64), although aliphatic nitro compounds can be reduced to amines with lithium aluminum hydride. When aromatic amines are reduced with this reagent, a2o compounds are produced. Nitriles, on the other hand, can be reduced to amines with lithium aluminum hydride or sodium borohydride under certain conditions. Other functional groups which can be reduced to amines using metal hydrides include amides, oximes, isocyanates, isothiocyanates, and a2ides (64). 

In Europe, the drive system of the Impact propelled the Opel Impuls2, a conversion vehicle based on the Opel Astra Caravan in 1991. A new, specifically developed AC induction drive unit with IGBT inverter technology was used to build a small fleet of Impuls vehicles see Figure 8.4). The fleet served as an automotive test bed for the integration of various advanced battery systems such as nickel-cadmium, nickel-metal hydride, sodium-nickel chloride, sodium-sulfur, and sealed lead-acid. 

Aldehydes and ketones undergo reductive amination when treated with ammonia, primary, or secondary amines, to give primary, secondary, or tertiary amines, respectively. The most commonly used laboratory reducing agent for this purpose is the metal hydride sodium cyanoborohydride, NaBH3CN. 

George and Barrie have extended their studies of the metallation of polymers to polyurethanes. Poly(ester-urethane)s based on diphenyl methane-4,4-di-iso-cyanate and toluene di-isocyanate were metallated with sodium hydride in THF. Metallation apparently occurs at the urethane link (Scheme 18) and these O... 

Variable results were observed with other Michael acceptors. Addition to methyl methacrylate was successful using metal hydrides (sodium was faster than calcium) or butyl lithium, while addition to crotonate or maleate esters failed in our hands. NVF reacted violently with acrolein, resulting in polymers. 

Sodium bis(trimethylsilyl)amide is another base that has been successfully used in a Michaelis-Becker synthesis of alkylphosphonates (Scheme 4.59) [110]. Similar to the other reactions described previously, the reaction proceeds through initial generation of a sodium diaUcylphosphonate followed by the addition of alkyl halide to generate the products. This base is attractive since it is relatively inexpensive and readily available as a solution. Overall, this type of base is significantly less hazardous to use than sodium metal or sodium hydride. The potassium salt of bis(trimethylsilyl)amide has also been used to promote the phosphonation of a benzyl bromide (Scheme 4.60) [111]. This chemistry was attractive as an aryl bromide was retained throughout the Michaelis-Becker chemistry and was available for further functionalization in subsequent reactions. 

For most laboratory scale reductions of aldehydes and ketones catalytic hydro genation has been replaced by methods based on metal hydride reducing agents The two most common reagents are sodium borohydride and lithium aluminum hydride... 

Sulfur dioxide Halogens, metal oxides, polymeric tubing, potassium chlorate, sodium hydride... 

Common catalyst compositions contain oxides or ionic forms of platinum, nickel, copper, cobalt, or palladium which are often present as mixtures of more than one metal. Metal hydrides, such as lithium aluminum hydride [16853-85-3] or sodium borohydride [16940-66-2] can also be used to reduce aldehydes. Depending on additional functionahties that may be present in the aldehyde molecule, specialized reducing reagents such as trimethoxyalurninum hydride or alkylboranes (less reactive and more selective) may be used. Other less industrially significant reduction procedures such as the Clemmensen reduction or the modified Wolff-Kishner reduction exist as well. 

Although a few simple hydrides were known before the twentieth century, the field of hydride chemistry did not become active until around the time of World War II. Commerce in hydrides began in 1937 when Metal Hydrides Inc. used calcium hydride [7789-78-8J, CaH2, to produce transition-metal powders. After World War II, lithium aluminum hydride [16853-85-3] LiAlH, and sodium borohydride [16940-66-2] NaBH, gained rapid acceptance in organic synthesis. Commercial appHcations of hydrides have continued to grow, such that hydrides have become important industrial chemicals manufactured and used on a large scale. 

Sodium hydride is manufactured by the reaction of hydrogen and molten sodium metal dispersed by vigorous agitation ia mineral oil (4). 

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