Sodium carbonate • zinc mixture

Sodium p-bromobenzenesulphonate, 550 Sodium carbonate - zinc mixture, 1042 Sodium cyanide, precautions in the use of, 409... 

Add 1 ml. of the alcohol-free ether to 0-1-0-15 g. of finely-powdered anhydrous zinc chloride and 0 5 g. of pure 3 5-dinitrobenzoyl chloride (Section 111,27,1) contained in a test-tube attach a small water condenser and reflux gently for 1 hour. Treat the reaction product with 10 ml. of 1-5N sodium carbonate solution, heat and stir the mixture for 1 minute upon a boiling water bath, allow to cool, and filter at the pump. Wash the precipitate with 5 ml. of 1 5N sodium carbonate solution and twice with 6 ml. of ether. Dry on a porous tile or upon a pad of filter paper. Transfer the crude ester to a test-tube and boil it with 10 ml. of chloroform or carbon tetrachloride filter the hot solution, if necessary. If the ester does not separate on cooling, evaporate to dryness on a water bath, and recrystallise the residue from 2-3 ml. of either of the above solvents. Determine the melting point of the resulting 3 5 dinitro benzoate (Section 111,27). 

When an organic compound is heated with a mixture of zinc powder and sodium carbonate, the nitrogen and halogens are converted into sodium cyanide and sodium hahdes respectively, and the sulphur into zinc sulphide (insoluble in water). The sodium cyanide and sodium hahdes are extracted with water and detected as in Lassaigne s method, whilst the zinc sulphide in the residue is decomposed with dilute acid and the hydrogen sulphide is identified with sodium plumbite or lead acetate paper. The test for nitrogen is thus not affected by the presence of sulphur this constitutes an advantage of the method. 

Prepare the zinc powder - sodium carbonate mixture by grinding together in a dry, clean mortar 25 g. of A.R. anhydrous sodium carbonate and 50 g. of the purest obtainable zinc powder. The reagent is unlikely to contain nitrogen, but traces of sulphur and halogens may be present. It is therefore essential to carry out a blank or control test for sulphur and halogens with every fresh batch of the mixture. 

MRH Barium chlorate 5.06/83, calcium chlorate 5.61/77, potassium chlorate 6.07/76, sodium bromate 4.98/80, sodium chlorate 7.32/75, zinc chlorate 6.11/76 Dry finely divided mixtures of red (or white) phosphorus with chlorates, bromates or iodates of barium, calcium, magnesium, potassium, sodium or zinc will readily explode on initiation by friction, impact or heat. Fires have been caused by accidental contact in the pocket between the red phosphorus in the friction strip on safety-match boxes and potassium chlorate tablets. Addition of a little water to a mixture of white or red phosphorus and potassium iodate causes a violent or explosive reaction. Addition of a little of a solution of phosphorus in carbon disulfide to potassium chlorate causes an explosion when the solvent evaporates. The extreme danger of mixtures of red phosphorus (or sulfur) with chlorates was recognised in the UK some 50 years ago when unlicenced preparation of such mixtures was prohibited by Orders in Council. 

Intimate mixtures of chlorates, bromates or iodates of barium, cadmium, calcium, magnesium, potassium, sodium or zinc, with finely divided aluminium, arsenic, copper carbon, phosphorus, sulfur hydrides of alkali- and alkaline earth-metals sulfides of antimony, arsenic, copper or tin metal cyanides, thiocyanates or impure manganese dioxide may react violently or explosively, either spontaneously (especially in presence of moisture) or on initiation by heat, friction, impact, sparks or addition of sulfuric acid [1], Mixtures of sodium or potassium chlorate with sulfur or phosphorus are rated as being exceptionally dangerous on frictional initiation. 

To a solution of 2-(trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-0-acetyl-3,4-di-deoxy-D-gfycero-a-D-gafacto-2-nonulopyranosylonate)-(2— 3)-2,4,6-tri-0-benzoyl-p-D-galactopyranoside 30 (210 mg, 0.18 mmol) and zinc chloride (30 mg, 0.220 mmol) in dichloromethane (2 mL) was added a,a-dichloromethyl methyl ether (40 jj,L, 0.434 mmol) at 0°C. The reaction mixture was stirred at room temperature for 4 h, then diluted with dichloromethane, and washed successively with cold dilute aqueous sodium carbonate solution and water, dried over NajSOj, and concentrated to give the title product (187 mg, 96%) mp 75°C, [a]D +42.36° (c 1.015, CHC13). 

An intimate mixture consisting of 1 molecular equivalent of the zinc salt of o-aminophenyl selenide and 2 equivalents of p-nitrobenzoyl chloride is fused for an hour at 100° C. The cooled melt is then pulverised and washed successively with water and sodium carbonate solution. Repeated crystallisation from glacial acetic acid gives pale yellow lustrous needles, M.pt. 211c C. (corr.). 

Cleaned silicon wafers were silylated with A/-(3-triethoxysilylpropyl)-12-nitro-dodecanamide in toluene (20 ml of a 2% solution) at room temperature under nitrogen overnight. The wafers were thoroughly washed with chloroform, methanol, and acetone in that order, and suspended in glacial acetic acid (5 ml). Zinc dust (200 mg) was added in small portions and the mixture set aside for 5 h. The wafers were recovered and washed several times with distilled water, sodium carbonate solution (1% aq.), and again with distilled water. After rinsing with acetone, the wafers were stored under nitrogen. 

About 2 grams of a mixture of sodium carbonate and potassium nitrate are melted in a porcelain crucible and about i gram of the substance, finely cut, gradually added to the fused mass. When cold, the mass is heated with water and the clear liquid decanted off, the residue being subsequently boiled with two separate quantities of 50 c.c. of water and filtered. The lead and zinc are left as carbonates and, after solution in acetic acid, may be identified in the usual way. The presence of zinc is also shown by the yellow colour of the hot, fused mass. 

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