1870.] Dr. A. W. Hofmann on the Aromatic Cyanates. Ill 



freezing-mixture, solidifies with difficulty, and, as a rule, only after stand- 

 ing some time. 



Tolylurethane is insoluble in water, but dissolves with ease in alcohol 

 and ether, and crystallizes from the former in fine long prisms, which melt 

 at 32°. 



Tolylic cyanate. — When distilled alone, the tolylurethane behaves like 

 phenylurethane, the greater part passing over undecomposed, whilst a 

 small portion is resolved into toluylic cyanate and alcohol. 



CO 



(C 7 H 7 )HN1 Q _ CO 1 N+ C 2 H 6 1 Q 



When the distillation is performed in the presence of phosphoric anhy- 

 dride, the alcohol is fixed, and the tolylic cyanate passes over in a nearly 

 pure state. It only requires rectification to be perfectly pure. Tolylic 

 cyanate is a colourless liquid, boiling at 185°, of high refractive power, 

 and a powerful odour exciting a copious flow of tears. 



A vapour-density determination in aniline vapour gave the following 

 results : — 



Theory. Expt. 

 Specific gravity of vapour compared with hy- I. n. 



drogen 66*5 64*6 65'7 



Specific gravity of vapour compared with air 4'61 4*48 4*56 



Tolylic cyanate behaves towards water and ammonia and their deriva- 

 tives like phenylic cyanate. On treatment with water ditolylurea is pro- 

 duced with evolution of carbonic acid ; with the alcohols it forms the cor- 

 responding urethanes, and with ammonia and the amines it yields a group 

 of compound ureas. 



Triethylphosphine produces the same change as in the phenyl-com- 

 pound ; it takes place, however, somewhat more slowly. , The very beau- 

 tiful crystalline compound thus formed I hope soon to be able to in- 

 vestigate. 



Xylyl Series. 



The experiments were precisely similar to those in the phenyl and tolyl 

 series. The reaction with xylidine is, however, somewhat more sluggish 

 than with aniline and toluidine. 



Xylylur ethane, 



crystallizes in fine needles, which melt at 58°. 

 Xy lytic cyanate, 



C 9 H 9 NO= c °° }N, 



is a colourless, highly refractive liquid of feeble odour, and attacking the 

 eyes but slightly. The boiling-point is about 200°. Its vapour-density 

 was taken in aniline vapour. 



