108 PROCEEDINGS OP THE AMERICAN ACADEMY 



following experimental portion, are sufficient to furnish the com- 

 plete proof that the isonitriles possess the constitution represented 

 by the formula E.NO: furthermore, the name carhylamine is no 

 longer justifiable for this class of compounds, because the members 

 are not bases, as this name represents. 



Experimental Part. 



I. On Phenylisocyanide, C 6 H 5 N=C=. 



Preparation of Phenylisocyanide. — To a solution of 240 grams 

 caustic potash in 800 c.c. alcohol (99%) is added slowly, by means 

 of a drop funnel, a solution of 100 grams aniline in 214 grams chlo- 

 roform. Eeaction sets in at first with great violence, so that the 

 solution soon reaches its boiling point. It is therefore necessary 

 to cool continually, and the temperature is best kept at about 50°, 

 because, if cooled too much, reaction sets in all at once, and with 

 violence. After standing for a short time, during which complete 

 reaction slowly takes place, and much potassic chloride has sepa- 

 rated out, the alcohol is distilled off* on a water bath, and a litre 

 of hot water poured over the residue, in order to dissolve the potas- 

 sic chloride. On cooling, the upper oily layer, consisting of ani- 

 line and phenylisocyanide, is drawn off, and the aqueous solution 

 extracted with ether. The ethereal solution is washed with 120 

 grams hydrochloric acid (sp. gr. 1.15), previously diluted to a litre; 

 this is best done in two portions, using three fourths at first, and 

 then the remainder. By this treatment all the unchanged aniline, 

 as well as some diphenylformamidine formed, go into the acid so- 

 lution, while the phenylisocyanide remains dissolved in the ether. 

 The ether is distilled off without first drying it, and the dark brown 

 colored residue distilled with steam. Phenylisocyanide is carried 

 over very quickly as a colorless oil, which on standing soon be- 

 comes colored pale green. It is again extracted with ether after 

 adding a small amount of dilute sulphuric acid, and the ethereal 

 solution dried with caustic potash, and, after getting rid of the 

 ether, the dark blue residual oil is distilled under reduced pres- 

 sure. Phenylisocyanide boils at 64° at 20 mm., at 71° at 30 mm., 

 at 78° at 40 mm. pressure, leaving a slight blue residue (poly- 

 meric product). 



* Small amounts of aniline and isonitrile are carried over with the alcohol, 

 which, however, it is not worth while to work up. It is not possible to use the 

 alcohol over again, since it contains chloroform. 



