Cyanide sodium

Sodium cyanide is very poisonous and must be handled with great care. The hands should be washed immediately after using it. All the residual solution.s containing alkali cyanides must be emptied into the main drain of the laboratory and washed down with a liberal supply of water they should never be treated with acid. 

The filtrate contains sodium cyanide, and should be washed down the sink with a liberal quantity of water. 

Cuprous cyanide solution. The most satisfactory method is to dissolve the cuprous cyanide (1 mol) in a solution of technical sodium cyanide (2 5-2-6 mols in 600 ml. of water). If it is desired to avoid the preparation of solid cuprous cyanide, the following procedure may be adopted. Cuprous chloride, prepared from 125 g. of copper sulphate crystals as described under 1 above, is suspended in 200 ml. of water contained in a 1-litre round-bottomed flask, which is fitted with a mechanical stirrer. A solution of 65 g. of technical sodium cyanide (96-98 per cent.) in 100 ml. of water is added and the mixture is stirred. The cuprous chloride passes into solution with considerable evolution of heat. As the cuprous cyanide is usually emplo3 ed in some modification of the diazo reaction, it is usual to cool the resulting solution in ice. 

Chrysean (10), prepared by bubbling hydrogen sulfide through a sodium cyanide solution, was among the first described thiazoles (53-57). Other 5-aminothiazoles are also most easily prepared bv hetero-cyclization (see Chapter 11. Section II.5.A). 

The carbonyl compound may be mixed with an aqueous solution of sodium or potassium cyanide and mineral acid is added, or the bisulphite compound may be treated with an equivalent quantity of sodium cyanide, for example  

Into a 1500 ml. round-bottomed flask place 97-5 g. of finely-powdered sodium cyanide (1), 125 ml. of water, and a few chips of porous porcelain. Attach a reflux condenser and warm on a water bath until all the sodium cyanide dissolves. Introduce a solution of 250 g. (196 ml.) of n-butyl bromide (Sections 111,35 and 111,37) in 290 ml. of pure methyl alcohol, and reflux gently on a water bath for 28-30 hours. Cool to room temperature and remove the sodium bromide which has separated by filtration through a sintered glass funnel at the pump wash the crystals with about 100 ml. of methyl alcohol. Transfer the filtrate and washings to From n caproamide by SOClj method. 

The only important precaution in this preparation is to ensure an excess of zinc chloride over sodium cyanide. If the latter is in excess, the zinc cyanide generally precipitates as a sticky mass, which is difficult to filter and unsatisfactory for the preparation of hydroxy-aldehydes. 

Indoleacetic acid In a 1-litre flask, fitted with a reflux condenser, place a solution of 35 2 g. of sodium cyanide in 70 ml. of water, then add 25 g. of gramine and 280 ml. of 95 per cent, ethanol. Reflux the mixture (steam bath) for 80 hours. Dilute the cooled reaction mixture with 35 ml. of water, shake with a little activated charcoal (e.g., Norit), filter and concentrate to about 350 ml. imder reduced pressure (water pump) in order to remove most of the alcohol. Cool to about 5°, filter off the solid and wash it with a little cold water keep the filtrate (A). Recrystallise the solid from alcohol-ether to give 5-0 g. of 3-indoleacetamide, m.p. 150-151°. 

Dichloroacetic acid is conveniently prepared by the action of calcium carbonate in the presence of a little sodium cyanide upon chloral hydrate, followed by acidification with concentrated hydrochloric acid  

Equip a 1-litre three-necked flask with a mechanical stirrer, a separatory funnel and a thermometer. Place a solution of 47 g. of sodium cyanide (or 62 g. of potassium cyanide) in 200 ml. of water in the flask, and introduce 58 g. (73-5 ml.) of pure acetone. Add slowly from the separatory fumiel, with constant stirring, 334 g. (275 ml.) of 30 per cent, sulphuric acid by weight. Do not allow the temperature to rise above 15-20° add crushed ice, if necessary, to the mixture by momentarily removing the thermometer. After all the acid has been added continue the stirring for 15 minutes. Extract the reaction mixture with three 50 ml. portions of ether, dry the ethereal extracts with anhydrous sodium or magnesium sulphate, remove most of the ether on a water bath and distil the residue rapidly under diminished pressure. The acetone cyanohydrin passes over at 80-82°/15 mm. The yield is 62 g. 

In a 500 ml. round-bottomed flask place 65 ml. of rectified spirit, 50 g. (47 5 ml.) of pure benzaldehyde (1) and a solution of 5 g. of sodium cyanide (96-98 per cent.) CAUTION) in 50 ml, of water. Attach a reflux condenser (preferably of the double surface type) and boil the mixture gently for half an hour (2). Cool the contents of the flask (preferably in an ice bath). Filter the crude benzoin, wash it with cold water, drain well (3) and dry. The yield of crude benzoin, which is white or pale yellow in colour, is 45 g. 

Fit a 2-litre round-bottomed flask with a two-holed stopper carrying a separatory funnel and a reflux condenser (Fig. Ill, 71,1). Place 147 g. of finely-powdered sodium cyanide and 150 ml. of water in the flask and 

Dichloroethanoic acid, CHCljCOOH. Low-melting solid, m.p. 5-6 "C, b.p. 194°C. Prepared by the action of copper powder on trichloroethanoic acid or by the action of sodium cyanide on chloral hydrate. 

Glutarlc acid (n =3), pimelic acid (n = 5) and suberic acid (n = 6) may be obtained from the corresponding dibromides. These are converted by aqueous - alcoholic potas-sium or sodium cyanide into the dinitriles, and this latter are smoothly hydrolysed by 50 per cent, sulphuric acid into the dicarboxybc acids  

Mandelic acid. This preparation is an example of the synthesis of an a-hydroxy acid by the cyanohydrin method. To avoid the use of the very volatile and extremely poisonous hquid hydrogen cyanide, the cyanohydrin (mandelonitrile) is prepared by treatment of the so um bisulphite addition compound of benzaldehj de (not isolated) with sodium cyanide  

Suberic acid. Prepare hexamethylene dibromide from hexamethy-lene glycol (Section 111,15) according to the procedure described in Section 111,35). Convert the 1 6-dibromohexane, b.p. H4r-115°/12 mm., into hexamethylene dicyanide, b.p. 178-180°/15 mm., by refluxing it with a 20-25 per eent. excess of aqueous - alcoholic sodium cyanide solution (compare Section 111,114), distilling off the hquid under diminished 

Conduct the preparation in the fume cupboard. Dissolve 250 g. of redistilled chloroacetic acid (Section 111,125) in 350 ml. of water contained in a 2 -5 litre round-bottomed flask. Warm the solution to about 50°, neutralise it by the cautious addition of 145 g. of anhydrous sodium carbonate in small portions cool the resulting solution to the laboratory temperature. Dissolve 150 g. of sodium cyanide powder (97-98 per cent. NaCN) in 375 ml. of water at 50-55°, cool to room temperature and add it to the sodium chloroacetate solution mix the solutions rapidly and cool in running water to prevent an appreciable rise in temperature. When all the sodium cyanide solution has been introduced, allow the temperature to rise when it reaches 95°, add 100 ml. of ice water and repeat the addition, if necessary, until the temperature no longer rises (1). Heat the solution on a water bath for an hour in order to complete the reaction. Cool the solution again to room temperature and slowly dis solve 120 g. of solid sodium hydroxide in it. Heat the solution on a water bath for 4 hours. Evolution of ammonia commences at 60-70° and becomes more vigorous as the temperature rises (2). Slowly add a solution of 300 g. of anhydrous calcium chloride in 900 ml. of water at 40° to the hot sodium malonate solution mix the solutions well after each addition. Allow the mixture to stand for 24 hours in order to convert the initial cheese-Uke precipitate of calcium malonate into a coarsely crystalline form. Decant the supernatant solution and wash the solid by decantation four times with 250 ml. portions of cold water. Filter at the pump. 

In order to detect these elements in organic compounds, it is necessary to convert them into ionlsable inorganie substanees so that the ionic tests of inoiganio qualitative analysis may be applied. This conversion may be accomplished by several methods, but the best procedure is to fuse the organic compound with metallio sodium (Lassalgne s test). In this way sodium cyanide, sodium sulphide and sodium halides are formed, which are readily identified. Thus  

Carry out this preparation in the fume cupboard. Dissolve 100 g. of chloroacetic acid (Section 111,125), contained in a large porcelain basin or casserole, in 200 ml. of water. Warm the solution to about 50°, using a 200° thermometer as a stirring rod. Introduce 90 g. of pure, powdered sodium bicarbonate in small quantities at a time with stirring maintain the temperature at 50-60° until effervescence ceases. Now add 80 g. of pure, finely-powdered potassium cyanide (or an equivalent quantity of sodium cyanide), stir the mixture without further warming until the 

---