66 Messrs. Steuhouse and Groves on Picrorocellin, [May 18, 



an aqueous solution of sodium hydrate was gradually added until all the 

 crystals had disappeared, a solution was obtained which, when filtered 

 and rendered acid with acetic acid, deposited crystals of very pure un- 

 altered picrorocellin equal in weight to about half those originally taken. 



The alcoholic mother liquors on being evaporated left an oily residue 

 insoluble in water. It was exceedingly soluble in hot spirit, however ; and 

 the solution, if sufficiently concentrated, deposited colourless crystals of 

 a new substance mixed with more or less picrorocellin. 



As from this experiment picrorocellin seemed to be altered by the 

 action of alkalis, a quantity of it was boiled with a concentrated solution 

 of sodium hydrate, when it became evident that it was japidly being 

 changed, and in a few minutes it became red, and fused to an oily mass 

 enclosing crystals of the unaltered substance. The whole was then allowed 

 to cool ; and after the soda solution had been poured off, the red mass 

 was gently heated with water, which readily dissolved most of it, leaving 

 merely the unattacked picrorocellin. The addition of sodium hydrate to 

 the deep yellow solution thus obtained threw down a yellowish-red resin- 

 ous mass, whilst acids caused the formation of a voluminous, almost 

 white precipitate. This readily aggregated to a plastic mass, which was 

 washed by kneading it in tepid water. During the action of caustic 

 soda on picrorocellin, a volatile substance is produced having a pleasant 

 aromatic odour. 



It was found, however, that the principal product of this reaction 

 could be obtained far more readily, and in a purer state, by operating 

 with dilute solutions of sodium hydrate. Tor this purpose 3 parts of 

 solid sodium hydrate were dissolved in 180 to 200 of boiling water, and then 

 10 parts of finely powdered picrorocellin were added ; the crystals dis- 

 solved rapidly in the boiling liquid, ammonia was given off in small 

 quantity, and after about an hour's digestion the reaction was considered 

 to be complete. When nearly cold, acetic acid was added to the solution 

 in slight excess ; this produced a glutinous kind of precipitate, which 

 could be moulded under the warm liquid into a stick closely resembhng 

 bleached shellac in appearance, being lustrous and silky. The product 

 was found, however, to be far from pure ; and in order to obtain it in that 

 state, it had to be crystallized successively from alcohol and from carbon 

 bisulphide. The crude product was therefore digested with two thirds 

 of its weight of boiling spirit until dissolved, and then set aside to cool. 

 After standing a considerable time, it deposited the new substance in 

 colourless crystals, which were collected on cotton wool on a vacuum fil- 

 ter, washed with a very small quantity of cold spirit, and dried. These 

 crystals were then boiled with 30 times their weight of carbon bisulphide 

 until dissolved, the solution filtered, and then concentrated to about half 

 its bulk by distillation. On cooling, the substance crystallized out in 

 large, brilliant, colourless prisms, amounting to from 40 to 45 per cent, of 

 the weight of the picrorocellin originally taken. These may be rendered 



