Sodium tetrahydroborate reaction with

GLICERINA (Spanish) (56-81-5) Combustible liquid (flash point 390°F/199°C). Violent reaction with strong oxidizers, acetic anhydride, calcium hypochloride, chlorine, chromic anhydride, chromium oxide, ethylene oxide, hydrogen peroxide, phosphorus triiodide, potassium permanganate, potassium peroxide, silver perchlorate, sodium hydride, sodium peroxide, sodium triiodide, sodium tetrahydroborate. Incompatible with strong acids, caustics, aliphatic amines, isocyanates, uranium fluoride. Able to polymerize above 293°F/145°C. 

In the chromium triad, the only claimed tetranuclear compound is the anion [Mo4(CO)u ]2 which was mentioned together with [Mo3(CO)14]2, in a study of the reaction of sodium tetrahydroborate and hexacarbonyl-molybdenum in liquid ammonia14). Later work failed to confirm the existence of the trinuclear anions, [M3(CO)i4]2 (M = Cr, Mo, W)109 1S0,169 and, therefore, the real existence of the tetranuclear anion also seems dubious. 

Reaction of diarylditellurides with arenediazonium salts (typical procedure). p-Methoxy phenyl p-tolyl telluride. With heating and stirring in an atmosphere of nitrogen, sodium tetrahydroborate was added in small portions to a solution of 9.4 g of bis(p-methoxyphenyl) ditelluride in a mixture of 50 mL of ethanol and 15 mL of benzene until the solution was decolourized completely (1.5 g was required). Then 8.24 g of p-toluenediazonium fluo-roborate was added rapidly and the mixture was stirred for 1 h and poured into dilute HCl. The oil formed was extracted with ether, and the extract was washed with water and dried over CaCl2. Ether was evaporated, and the residue was dissolved in benzene and chromatographed on alumina (eluent hexane). After the evaporation of hexane, 4.8 g (36%) of the telluride was isolated, m.p. 64-64.5°C (hexane). 

Another work on the Hquid phase hydrogenation of acetophenone is that of Casagrande et al. The reaction was studied over a series of silica-supported bimetallic catalysts with various Ru/Cr atomic ratios, which were prepared by reduction at room temperature with aqueous sodium tetrahydroborate. The nanostructured catalysts are very active in the low-pressure hydrogenation of acetophenone, although the selectivity towards 1-phenylethanol did not surpass 22% at 90% conversion. The addition of chromium salts to the starting solution gave rise to... 

Amino acids undergo a condensation reaction with pyridoxal in alkaline medium to form a Schiff base which can be converted into stable pyridoxyl-amino acids by catalytic reduction or by reduction with sodium tetrahydroborate. The reactions involved are illustrated in Fig. 4.46. The resulting derivatives can be detected in quantities as low as 5-10"10 moles by fluorescence at 332 nm (excitation) and 400 nm (emission). Column chromatography may be used to separate die pyridoxyl-amino acid derivatives [93,94]. 

Pohl, P. 2004. Recent advances in chemical vapor generation via reaction with sodium tetrahydroborate. 

Long and Wallbridge 120> report the preparation of mixed methyl derivatives of diborane(6) from the reaction of trimethylborane with lithium or sodium tetrahydroborate(— 1) and hydrogen chloride in the presence of suitable Lewis acid. 

Powdered sodium tetrahydroborate(l -) (0.37 g, 0.01 mol) is added in three portions at about 30-min intervals to a suspension of dichlorobis(tri-isopropylphosphine)nickel (4.5 g, 0.01 mol) in diethyl ether (300 mL) and 95% ethanol (50 mL) in a 500-mL three-necked flask with an argon inlet and a gas bubbler vented to the hood. The reaction mixture is stirred with a magnetic stirring bar at 20° for approximately 5 hr. Gas evolution is observed, and the nickel complex dissolves gradually. After all the nickel compound is dissolved, the solution is filtered into a 500-mL two-necked flask and the solvent is removed under reduced pressure. The yellow residue is extracted with petroleum ether (200 mL), and the solution is washed with two 50-mL portions of water. The petroleum layer is separated, dried with 15 g of anhydrous sodium sulfate, which is washed with two 10-mL portions of the solvent which are added to the petroleum extract the combined extract is then filtered and concentrated in vacuo. The saturated solution (approximately 100 mL) is cooled to —78° in a Dry lce-2-propanol mixture overnight. The crystals which are formed are filtered, washed with a small amount (approximately 10 mL) of petroleum ether at 0°, and dried in vacuo to give brown crystals, mp 65-66° (decomposes). (Yield 2.5 g, 60%.) Anal. Calcd. for Cl8H43ClNiP2 C, 52.1 H, 10.4 Ni, 14.1. Found C, 52.3 H, 9.7 Ni, 14.1. 

A suspension of bromobis[2,3-butanedione dioximato( 1 -)] (4-rerr-butylpyri-dine)cobalt(III) (2.5 g, 5.0 mmole) (see above) in 20 mL of methanol in a 100 mL, three-necked flask is vigorously stirred under an N2 purge for 10 minutes. While it is stirred and purged with N2, solid sodium tetrahydroborate (0.5 g, 13 mmole) is gradually added in about 0.1-g portions. Upon addition of the sodium tetrahydroborate, the solution becomes warm, shows considerable effervescence due to hydrogen evolution, and becomes homogeneous. The development of the dark blue-black color is characteristic of the reduced Co(I) species. Then 2-bromoethyl ethyl ether (0.56 mL, 5.0 mmole) is added and the solution turns red-brown, indicating the presence of the alkylcobalt(III) species. The reaction mixture is then stirred for 15 minutes. To obtain maximum yields, another 0.25 g of solid sodium tetrahydroborate is added, followed by addition of an extra 0.25 mL of 2-bromoethyl ethyl ether. The reaction mixture is stirred for another 10 minutes. Further additions of sodium tetrahydroborate and 2-bromo-... 

Caution. The sodium tetrahydroborate should be added slowly to prevent foaming of the reaction mixture from the reaction vessel. Alkyl chloromethyl ethers are potent carcinogens13 and should be handled and disposed of with appropriate precautions. 

The preparations described here are developed from published work by Malatesta et al.5 and from more recent studies in the contributors own laboratory.2 The cobalt and nickel complexes are prepared by reduction of the corresponding metal nitrates with sodium tetrahydroborate in the presence of excess ligand, whereas the syntheses of the rhodium and platinum complexes involve simple ligand exchange processes. The preparative routes are suitable for use with triphenyl- or p-substituted triphenyl phosphites reactions involving o- or m-substituted triphenyl phosphites give much reduced yields of products which are difficult to crystallize and are very air-sensitive. These features probably reflect the unfavorable stereochemistry of the o- and m-substituted ligands. 

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