112 Dr. A. W. Hofmann on the Aromatic Cyanates. [Nov. 24 



Theory. Expt. 



Specific gravity of vapour compared with hydrogen .... 7 3' 50 74' 69 

 „ „ „ compared with air 5*10 5* 18 



Xylylic cyanate exhibits the same reactions as those which are so pro- 

 minent in the corresponding members of the phenyl and tolyl series, but 

 somewhat weaker. The combinations which take place almost immediately 

 in the case of phenylic and tolylic cyanates often require days with the 

 xylylic cyanate. Even in the presence of triethylphosphine xylylic cyanate 

 solidifies but slowly. 



Naphthyl Series. 



Naphthylur ethane. — The formation of this analogue of urethane was 

 effected by the action of chlorocarbonic ether on naphthylamine. It is 

 insoluble in water, more soluble in alcohol, and crystallizes from the latter 

 in needles which melt at 79°. Its composition is expressed by the for- 

 mula 



C 18 H I8N 2 = C °( C "H,)HN| . 



Naphthylic cyanate. — A short notice of this compound has already 

 appeared. When I had found that diphenylcarbamide gave phenylic cya- 

 nate by distillation with phosphoric anhydride, Mr. Vincent Hall* made 

 the corresponding experiment in the naphthyl series, but only obtained a 

 very small quantity of the naphthyl compound. The formation of the 

 naphthylic cyanate by this method was, however, established. 



The naphthylic cyanate is obtained in considerable quantity by the dis- 

 tillation of naphthylurethane with phosphoric anhydride. It is a colour- 

 less, not very mobile fluid, whose boiling-point is about 269°-270°. Its 

 vapour has the pungent odour which is peculiar to the cyanates, but at the 

 ordinary temperature naphthylic cyanate is almost odourless. Its com- 

 position is expressed by the formula 



C n H T NO=CO H J N . 



I have, moreover, satisfied myself of its correctness by the reactions of the 

 body. On considering its behaviour with water and alcohol, and their de- 

 rivatives, there can be no doubt as to the nature of the compound. The 

 facility with which these reactions take place with the naphthyl compound 

 is remarkable. The naphthylic cyanate acts with incomparably greater 

 quickness and precision than the analogous xylyl-com pound ; this is par- 

 ticularly shown in the action of triethylphosphine, which causes the cyanate 

 of the naphthyl series to solidify almost instantaneously. 



I have to give my best thanks to Mr. F. Hobrecker for his efficient 

 assistance in the prosecution of the above research. 



* Proc. Koy. Soc. vol. ix. p. 365. 



