Sodium azide purification

Silicon, higher chlorides of, 42 Silicon tetrabromide, 38, 40 Silicon tetrachloride, 44 Silicopropane, octachloro, 44 Silicotungstic acid, 129 analysis, 131 ether complex, 131 Silver, metallic, 4 Silver chloride, reduction of, 3 Silver cyanamide, 98 Silver residues, purification of, 2 Sodium amalgam, 10 Sodium amide, 74 Sodium azide, purification of, 79 Sodium azidodithiocarbonate, 82 Sodium butoxide, 88 Sodium hypochlorite (solution), 90 Sodium iodate, 168 Sodium metaperiodate, 170 Sodium paraperiodate, chlorine method, 169 persulfate method, 170 Strontium amalgam, 11 Sulfur hexafluoride, 121 Sulfuryl chloride, 114... 

Another method was developed for the synthesis of 5,8-methano-3,l-benzoxazine-2,4-diones 157. The A-BOC amino acid 156 was prepared from the half ester 155 without purification of the intermediates. Thus, 155 was treated with ethyl chloroformate, and subsequently with sodium azide. 

Azidoformic esters such as 342 react with Cgg in a [2-tl] addition (Scheme 4.70), if the temperature is high enough to induce the loss of nitrogen prior to addition, otherwise a [3-1-2] addition can be observed (Section 4.3.2) [172, 395, 397]. Typical conditions include heating of the mixture in solvents such as tetrachloroethane [395, 397, 398], chloronaphfhalene [397] or toluene [396] at 110-160 °C. These conditions also afford multiple addition products [172]. To avoid potential hazard during purification of the azido formiates, they were also generated in situ in one pot by the reaction of chloro-formic ester with sodium azide [396]. 

Only the preparation of potassium azide is described here. However, the method outlined below can be adapted to the preparation of the alkali and alkaline earth azides in general. It is also suggested for the purification of technical sodium azide. The usual methods for the synthesis of sodium azide by the nitrous oxide-sodium amide3 method or the hydrazine-alkyl nitrite4 procedure have either not... 

To a solution of (R)-N-[[3-(3-fluoro-4-morpholinyl)phenyl]-2-oxo-5-oxazolidinyl]methane sulfonate (9.05 g) in 200 mL of DMF was added 6.367 g of sodium azide, and the mixture heated at 85°C overnight. The mixture was cooled and poured into 500 mL of water and 150 mL of ethyl acetate. The aqueous layer was extracted with ethyl acetate, and the combined organic layers were dried (MgS04), and concentrated in vacuum. The brown oil of (R)-N-[[3-(3-fluoro-4-morpholinyl)phenyl)-2-oxo-5-oxazolidinyl]methyl]azide, containing some DMF, was utilized without further purification. 

To a solution of 5-methoxymethoxy-7-oxa-bicyclo[4.1.0]hept-3-ene-3-carboxylic acid methyl ester (4.9 g, 22.9 mmol) in 8/l-Me0H/H20 (175 ml, v/v) was added sodium azide (7.44 g, 114.5 mmol) and ammonium chloride (2.69 g, 50.4 mmol) and the mixture was refluxed for 15 h. The reaction was diluted with water (75 ml) to dissolve precipitated salts and the solution was concentrated to remove methanol. The resulting aqueous phase containing a precipitated oily residue was diluted to a volume of 200 ml with water and was extracted with ethyl acetate (3 times 100 ml). The combined organic extracts were washed with saturated NaCI (100 ml), dried (MgS04), filtered and evaporated. The crude was purified on silica gel (1/1-hexane/ethyl acetate) to afford 5-azido-4-hydroxy-3-methoxymethoxy-cyclohex-l-ene-l-carboxylic acid methyl ester (5.09 g, 86%) as a pale yellow oil. Subsequent preparations of 5-azido-4-hydroxy-3-methoxymethoxy-cyclohex-l-ene-l-carboxylic acid methyl ester provided material which was of sufficient purity to use in the next step without further purification. 

Sodium amide, 1 74, 2 80, 128, 134 Sodium amidophosphate (Na2P03NH2), 6 100 anhydrous, for preparation of tetrasodium imidodiphos-phate, 6 101 Sodium azide, 2 139 purification of, 1 79 Sodium azidodithiocarbonate, solution of, 1 82 Sodium butoxide, 1 88 Sodium carbonate, Na2C03, light, for preparation of chlorine (I) oxide, 5 159... 

Diphenyl phosphorazldate is prepared by the action of sodium azide with diphenyl phosphorochlorldate (preceding procedure, this volume).3 It 1s also available from Aldrich Chemical Co. and was used after purification by distillation at 134-136°C (0.2 mm). WARNING Diphenyl phosphorazidate may produce explosive hydrogen azide when it 1s 1n contact with moisture for a long time. When diphenyl phosphorazidate, which has been stored for a long time, is used, 1t should be washed with saturated aqueous sodium bicarbonate and dried over sodium sulfate before distillation. 

Sodium azide was obtained from Alpha Inorganics, Inc., Beverly, Massachusetts, and the freshly opened material was used without further purification or drying. 

The purification procedure using this immunoaffinity column has been optimized as follows After extraction with a Sep-Pak PS2 cartridge, the extract is dissolved in 25 mM Tris-HCl buffer (pH 7.2) containing 1 mM EDTA, 0.15 M sodium chloride, and 0.1% sodium azide (Tris-HCl buffer A) with 0.1 % BSA (Tris-HCl buffer B) (5 mL), and the solution is loaded onto an immunoaffinity column, which is preconditioned with Tris-HCl buffer B (10 mL). After washing with Tris-HCl buffer A (10 mL) and distilled water (10 mL), the microcystin fraction is eluted with 100% dimethylformamide (DMF) (2.5 mL). The eluate is then dried on a hot block (60 °C) under a constant stream of nitrogen. The residue is dissolved in 30% methanol-water (0.5 mL) and then subjected to HPLC-photodiode array detection (HPLC-PDA) and LC/ MS analysis. The immunoaffinity column is regenerated by washing with Tris-HCl buffer B (10 mL) before each reuse. 

The following chemicals were obtained from the Aldrich Chemical Company, Inc., and were used without further purification p-acetamidoben2enesulfonyl chloride, 97% acetone, 99.9+%, HPLC grade sodium azide, 99% ethyl acetoacetate, 99% triethylamine, 99% rhodium(ll) acetate dimer phenylacetylene, 98%. The following solvents were obtained from Fisher Scientific and were used without further purification toluene, certified A. C. S. ethyl ether (Solvent grade. Concentrated) petroleum ether, certified A. C. S. Dichloromethane was distilled from calcium hydride. 

All these techniques tend to lower the ionality of the agar gel the rigidity is thereby increased, whereas the intensity of the electroosmotic flow is decreased. It follows that results with ImEl are comparable only if identical conditions have prevailed during the foregoing purification. The following stock buffer solutions have an ionic strength of t/2 = 0.1 (W4) when the specified quantities of constituents are made up to 1 liter with distilled water (plus 0.5 g sodium azide). 

Packaging, product, or purification - The amount of the liquid product, the concentration of antibody in the product (1 mg/ml is ideal), additives (e.g., sodium azide, glycerol), the source (e.g., whole serum, supernatant, ascites), and purification, if any. 

Mittal, C. K., Kimura, H., and Murad, F. (1977). Purification and properties of a protein factor required for sodium azide activation of guanylation cyclase. J. Biol. Chem. 252, 4384-4390. 

In summary, aqueous hydrazoic acid solutions up to 1 molar are conveniently made by cation exchange and are obtained chemically pure from anion pure (nitrate) sodium azide and a prepurified resin. Purification of the latter by washing the heavy metals out as chloro complexes is simple in principle, but time-consuming. For projects requiring numerous hydrazoic acid batches the approach has its advantages, but for single preparations distillation methods are preferable. 

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