Calcium aluminum hydride

Calcium acetylide, 11 182-183 Calcium aluminum hydride, preparation and properties of, 8 327-329 Calcium borates, 25 218-219 stability ranges, 25 209-210 structures, 25 190-195, 197-199 in water, 25 218... 

Aluminum Calcium Hydride. Calcium tetrahydro-aluntittate calcium aluminum hydride. ALCaHfi mot wt 102.10. Ai 52-85%, C 39.26%, H 7.89%. Ca(AfH4)r Prepd by the interaction of aluminum chloride and calcium hydride in teirahydrofuran Sehwab, Wintersberger, Z. Naturforsch. 8b, 690 (1953) Conn, Taylor, U.S. pat. 2,999,005 (1961 to Merck Co.). 

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. 

Good yields of phenylarsine [822-65-17, C H As, have been obtained by the reaction of phenylarsenic tetrachloride [29181-03-17, C H AsCl, or phenyldichloroarsine [696-28-6], C3H3ASCI25 with lithium aluminum hydride or lithium borohydride (41). Electrolytic reduction has also been used to convert arsonic acids to primary arsines (42). Another method for preparing primary arsines involves the reaction of arsine with calcium and subsequent addition of an alkyl haUde. Thus methylarsine [593-52-2], CH As, is obtained in 80% yield (43) ... 

Compound 7 is reduced to 2-benzamidocinnamyl alcohol by calcium borohydride in hydroxylic solvents at low temperatures. This reduction had been accomplished previously using lithium aluminum hydride in tetrahydrofuran. 

A 300 ml three-neck flask equipped with condenser, stirrer, dropping funnel, dry nitrogen inlet tube, and containing 5.5 g (0.145 mol) lithium aluminum hydride LAH suspension in 100 ml anhydrous diethyl ether, was placed in an ice bath. Over a period of 25 min 30 ml (0.123 mol) 1 was added dropwise into the stirred suspension. The mixture was stirred for an additional hour at 0 °C, then poured over a mixture of 50 ml ether, 100 g crushed ice, and 50 ml ice water with stirring. When necessary more crushed ice was added to cool the mixture. The layers were separated, and the organic layer was concentrated first by distillation over calcium hydride, then by vacuum distillation over calcium hydride. The yield of 4 was 22.5 g (86%). Bp. 78-9 °C, 0.4 mm. The product was stored in a freezer. The structure of 4 was confirmed by its H NMR spectrum as shown in Fig. 4. 

Tetrahydrofuran from E. I. du Pont de Nemours and Company can be dried conveniently by adding to it lithium aluminum hydride in small portions until no further reaction (evolution of hydrogen) ensues. After the mixture has been stirred for a few minutes, most of the tetrahydrofuran is distilled from it with stirring (to prevent bumping) (Note 3), and collected in a receiver protected from moisture by a calcium chloride tube. 

A 2-1. three-necked round-bottomed flask in an electric heating mantle is fitted with a mercury-sealed Hershberg stirrer, a dropping funnel, and an efficient reflux condenser topped with a tube containing soda lime and calcium chloride. In this flask are placed 21.3 g. (0.56 mole) of pulverized lithium aluminum hydride (Note 1) and 300 ml. of dry ether. The mixture is heated under reflux until most of the hydride has dissolved. A solution... 

The required working time is 3 to 4 hours. All equipment is thoroughly dried prior to use and is flushed with an inert gas (argon or nitrogen). Commercial sodium hydroborate is used without purification. The dimethyl ether of diethylene glycol (diglyme) is refluxed over calcium hydride for 8 hours and subsequently distilled over lithium tetrahydroaluminate (lithium aluminum hydride). Commercial tri-n-butylamine is refluxed with acetic anhydride and distilled at atmospheric pressure. 

Laughing gas, see Nitrogen(I) oxide Lautarite, see Calcium iodate Lawrencite, see Iron(II) chloride Leehatelierite, see Silicon dioxide Lime, see Calcium oxide Litharge, see Lead(II) oxide Lithium aluminum hydride, see Lithium tetrahydri-doaluminate... 

The 1,2-dimethoxyethane (Ansul Chemical Co.) was predried for several days over calcium hydride, filtered, and stored over lithium aluminum hydride prior to its distillation at atmospheric pressure immediately before use. For a larger-scale preparation it is expeditious to distil simultaneously from two 5-1. flasks rather than from a single large one. Under these conditions, distillation of the glyme can be completed in 8-10 hours. 

Before use, 1,2-dimethoxyethane (ethylene glycol dimethyl ether) was partially dried over anhydrous calcium chloride and then distilled from lithium aluminum hydride. It was stored over sodium ribbon. 

Diglyme (Ansul Ether 141) was predried over calcium hydride and distilled under reduced pressure from lithium aluminum hydride b.p. 62-63° (15 mm.).3 The yield of olefin is dependent on the dryness of the solvent. The formation of 2-phenyl-2H-perfluoropropane is favored by the presence of water in the solvent. 

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

Complex aluminum and boron hydrides can contain other cations. The following compounds are prepared by metathetical reactions of lithium aluminum hydride or sodium borohydride with the appropriate salts of other metals sodium aluminum hydride [55], magnesium aluminum hydride [59], lithium borohydride [90], potassium borohydride [9i], calcium borohydride [92] and tetrabutylammonium borohydride [95]. 

More reliable therefore is reduction with lithium aluminum hydride, lithium borohydride or calcium borohydride, which do not hydrogenolyze hydroxy groups [92]. 

Dichloromethane and triethylamine were distilled from calcium hydride before use. Silica gel 60. 0.040-0.063 mm (Merck) was used for column choromatography. Lithium aluminum hydride (95%, powder) was obtained from Aldrich Chemical Co., Inc. 

Reacts with calcium and magnesium hydrides in tetrahydrofuran forming tetrahydro aluminates, Ca(AlH4)2 reacts with hydrides of alkali metals in ether forming aluminum hydride ... 

Numerous methods for the synthesis of salicyl alcohol exist. These involve the reduction of salicylaldehyde or of salicylic acid and its derivatives. The alcohol can be prepared in almost theoretical yield by the reduction of salicylaldehyde with sodium amalgam, sodium borohydride, or lithium aluminum hydride by catalytic hydrogenation over platinum black or Raney nickel or by hydrogenation over platinum and ferrous chloride in alcohol. The electrolytic reduction of salicylaldehyde in sodium bicarbonate solution at a mercury cathode with carbon dioxide passed into the mixture also yields saligenin. It is formed by the electrolytic reduction at lead electrodes of salicylic acids in aqueous alcoholic solution or sodium salicylate in the presence of boric acid and sodium sulfate. Salicylamide in aqueous alcohol solution acidified with acetic acid is reduced to salicyl alcohol by sodium amalgam in 63% yield. Salicyl alcohol forms along with -hydroxybenzyl alcohol by the action of formaldehyde on phenol in the presence of sodium hydroxide or calcium oxide. High yields of salicyl alcohol from phenol and formaldehyde in the presence of a molar equivalent of ether additives have been reported (60). Phenyl metaborate prepared from phenol and boric acid yields salicyl alcohol after treatment with formaldehyde and hydrolysis (61). 

S)-2-Chloropropan-l-ol. Into a 2-L, three-necked, round-bottomed flask equipped with a mechanical stirrer, 250 mL dropping funnel, stopper (Note l) and an efficient reflux condenser fitted with a calcium chloride drying tube, is placed 9.1 g (0.24 mol) of lithium aluminum hydride, 400 mL of dry diethyl ether is added with caution. The slurry is cooled in an ice bath and a... 

Byproducts of this rearrangement are cyclobutenes, cyclopropane derivatives and allenic alcohols. The ratio of these products depends on the substitution of the substrate and on the reaction conditions. For example, 3-methyl-5-tosyloxypenta-l,2-diene (3) gives 75% of 1-methyl-2-methylenecyclobutanol (4) upon hydrolysis with water and calcium carbonate at 100 °C, while acetolysis with acetic acid/sodium acetate at 80 °C, and subsequent treatment with lithium aluminum hydride, provides only 37% of the cyclobutanol.12... 

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