1876.] Messrs. Stenhouse and Groves on Picr^orocellin. 



65 



pouring off the clear liquid from the colourless crystals which were 

 formed, and adding excess of soda. 



Xanthorocellin is soluble in warm concentrated sulphuric acid with a 

 brilliant orange-colour ; but on adding water, the substance is precipitated 

 unaltered. If the acid solution be strongly heated, however, it effervesces 

 slightly, and becomes somewhat darker in colour : the addition of water 

 to this no longer produces a precipitate. 



Xanthorocellin dissolves in cold nitric acid, and if water be at once 

 added the substance is precipitated apparently unaltered. On allowing 

 the nitric acid solution to stand for some time, however, or on gently 

 heating the mixture, decomposition takes place with the formation of 

 new compounds. These may be more conveniently obtained, however, 

 by the action of nitric acid on the substance dissolved in glacial acetic 

 acid, in the following manner : — 5 grams of xanthorocellin were dissolved 

 in 10 c. c. of boiling acetic acid, and the solution rapidly cooled, but with- 

 out agitation, so as to avoid as much as possible causing the substance to 

 crystallize out ; 5 c. c. of nitric acid (specific gravity I'-io) were then 

 added, the whole thoroughly mixed and gently heated in a water bath 

 until the action had set in. When this took place, the source of heat 

 was withdrawn, the heat developed by the reaction being sufficient to 

 cause the liquid to boil; large quantities of nitrous fumes were given off, 

 and lustrous scales soon began to appear in the liquid. If, as sometimes 

 happened, the action became too violent and threatened to eject the 

 contents from the flask, it was easily moderated by plunging the latter into 

 cold water for a few seconds. As soon as the reaction was complete, the 

 contents of the flask were poured into a beaker, and put aside for a few 

 hours ; the solid crystalline mass thus obtained was then thoroughly in- 

 corporated with 30 c. c. of spirit, which dissolved nearly every thing except 

 the scales. The latter were collected on a Bunsen filter, and washed 

 thoroughly with cold spirit, in which they are almost insoluble. The 

 yield of the new substance is about 35 per cent, of the xanthorocellin ori- 

 ginally taken ; it crystallizes in beautifully white hexagonal plates, which 

 do not melt at 275°, but begin to undergo decomposition below that tem- 

 perature. The spirituous washings from these crystals, obtained when 

 the crude product was treated with alcohol, were allowed to evaporate 

 spontaneously, until the latter had disappeared. On distilling the residue 

 in a current of steam, some benzoic aldehyde passed over with the 

 aqueous vapour, but no hydrocyanic acid could be detected in the distil- 

 late. The crystalline substance left lq the retort appears to be a nitro- 

 acid of high melting-point, totally different in its properties, however, 

 from nitrobenzoic acid. We hope to be able, at some future time, to 

 examiue the products of this interesting reaction more fully. 



Action of sodium hydrate on picrorocelUn. 

 When picrorocellin was boiled with three times its weight of spirit, and 



TOL. XXV. r 



