Tolunitrile p-tolyl cyanide

Cuprous cyandide solution (compare Section 11,50, 3). Prepare the following solutions — 

Warm the copper sulphate solution to 50-60°, and add dilute sulphuric acid until it is acid to Congo red. Add the sodium bisulphite solution. 

Hydrolysis of p-tolunitrile to p-toluic acid. Boil a mixture of 5 g. of p-tolunitrile, 80 ml. of 10 per cent, aqueous sodium hydroxide solution and 15 ml. of alcohol under a reflux condenser. (The alcohol is added to prevent the nitrile, which volatUises in the steam, from crystalhsing in the condenser it also increases the speed of hydrolysis. The alcohol may be omitted in the hydrolysis of nitriles which are hquid at the ordinary temperature, e.g., benzo-nitrUe.) The solution becomes clear after heating for about 1 hour, but continue the boiling for a total period of 1 - 5 hours to ensure complete hydrolysis. Detach the condenser and boil the solution for a few minutes in the open flask to remove dissolved ammonia and incidentally some of the alcohol CAUTION /). Cool, and add concentrated hydrochloric acid until precipitation of the p-toluic acid is complete. When cold, filter off the p-toluic acid with suction and wash with a little cold water. Recrystallise from a mixture of equal volumes of water and alcohol (methylated spirit) or from benzene. The yield of p-toluic acid, m.p. 178°, is 5-5 g. 

Benzonitrile (phenyl cyanide). Prepare a cuprous cyanide solution in a 500 ml. round-bottomed flask as above, but use the following quantities 65 g. of crystallised copper sulphate in 205 ml. of water, 18 g. of sodium bisulphite in 52 ml. of water, and 18 g. of potassium cyanide in 

of water dissolve the precipitated cuprous cyanide in a solution of 26 g. of sodium cyanide in 65 ml. of water or of 33 5 g. of potassium cyanide in 90 ml. of water. Diazotise 20 g. (19-6 ml.) of aniline, following the experimental details given vmder lodobenzene (Section IV,60). Add the cold phenyldiazonium chloride solution to the cuprous cyanide solution warmed at 60-70° and proceed as for ip-Tolunilrile. Extract the steam distillate with three 30 ml. portions of ether, shake the ethereal solution with 20 ml. of 10 per cent, sodium hydroxide solution (to remove traces of phenol produced by the decomposition of the diazonium chloride solution), then with an equal volume of dilute sulphuric acid (to remove traces of the evil-smelling phenyl iso-cyanide CgHjNC), and finally with an equal volume of water. Dry the ethereal extract over anhydrous magnesium sulphate or calcium chloride, distil oflF the ether from a small flask using the apparatus shown in Fig. II, 13, 4 then fit a short air condenser to the flask (Fig. II, 13, 2) and distil the benzonitrUe. Collect the fraction of b.p. 188-191°. The yield is 16 g. 

Hydrolysis of benzonitrile to benzoic acid. Boil 5 1 g. (5 ml.) of benzonitrile and 80 ml. of 10 per cent, sodium hydroxide solution in a 250 ml. round-bottomed flask fitted with a reflux water condenser until the condensed liquid contains no oily drops (about 45 minutes). Remove the condenser, and boil the solution in an open flask for a few minutes to remove free ammonia. Cool the liquid, and add concentrated hydrochloric acid, cautiously with shaking, until precipitation of benzoic acid is complete. Cool, filter the benzoic acid with suction, and wash with cold water dry upon filter paper in the air. The benzoic acid (5-8 g.) thus obtained should be pure (m.p. 121°). Recrystal lise a small quantity from hot water and redetermine the m.p. 

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Experiment 6.76 p-TOLUNITRILE (p-Tolyl Cyanide) p-Me-C6H4-NH2 p-Me-C6H4-N=N Cl p-Me-C6H4-CN... 

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