Dr. Hofmann on Phosphoretted Ureas. 361 



cyanic acid and some of its derivatives with phosphoretted hydrogen 

 and its homologues, in the hope of producing combinations similar 

 in constitution to the ureas, but differing from these substances by 

 containing phosphorus in the place of one equivalent of nitrogen. 



The action of cyanate and sulphocyanide of phenyle, an account of 

 which I have lately* submitted to the Royal Society, upon triethyl- 

 phosphine, seemed to include the conditions for the realization of 

 such compounds. 



On bringing cyanate of phenyle in contact with triethylphosphine, 

 a most lively reaction ensues ; the mixture begins to boil, and the 

 phosphorus-base is apt to be inflamed. On cooling, the liquid soli- 

 difies into a crystalline mass, which is insoluble in water, soluble in 

 alcohol and ether, and crystallizes from the latter solvent in beautiful 

 little square tables, tasteless, inodorous, and infusible at 100° C. On 

 submitting this compound to analysis, I was surprised to find that 

 it contained no phosphorus, and that it exhibited the composition 

 of the original cyanate of phenyle, from which it differs so essentially 

 in its properties. Tliis substance is the cyanurate of phemjle, gene- 

 rated from the cyanate by simple transposition of the elements. The 

 triethylphosphine participates only indirectly in the reaction ; in 

 giving rise to the transformation of the cyanate, the phosphorous 

 body plays the part of a ferment, a comparison which is moreover 

 suggested by the large proportion of cyanate over which the influence 

 of a minute quantity of phosphorus-base extends. A glass rod 

 moistened with triethylphosphine solidifies, almost instantaneously, 

 a considerable quantity of the cyanate. The transformation of the 

 cyanate under tbe influence of triethylphosphine, into cyanurate, 

 although the principal phase of the reaction, is attended by other 

 changes which I intend to examine more minutely by and by. 



Very different results were obtained by substituting for the cyanate 

 the sulphocyanide of phenyle. The reaction between this body and 

 triethylphosphine is very violent, and frequently gives rise to the in- 

 flammation of the phosphorus-base. The mixture assumes a deep 

 yellow colour, and often deposits splendid yellow needles on cooling ; 

 frequentljr, however, it remains liquid for hours and even for days, 

 but suddenly solidifies, when touched with a glass rod, into a hard, 

 yellow, crystalline mass. This substance is insoluble in water; it 

 dissolves with the greatest facility in alcohol, hot or cold, likewise in 

 warm, less so in cold ether. Kecrystallization from boiling ether 

 affords, in fact, the best means of procuring the new body in a state 

 of purity. This end is likewise considerably facihtated, by allowing 

 the sulphocyanide of phenyle to act u])on the triethylphosphine in the 

 presence of a considerable quantity of ether. 



In the pure state tbe new compound presents itself in the form of 

 well-defined prisms of uranium-yellow colour, which fuse at Gl° C. 

 They cannot be heated nmch beyond their fusing-point without being 

 altered; at 100" C. they are entirely decomposed, evolving a most 

 peculiar odour, which is also observed on evaporating the ethereal 

 mother-liquor. 



* Proceedings, vol. ix. p. 274. 



Phil. Mag. S. 4. Vol. 17. No. 115. May 1859. 2 B 



