1871.] 



Compounds of the Orcins. 



411 



powder is gradually added to strong nitric acid cooled by a freezing-mix- 

 ture, it dissolves with a pale brown coloration, but without the slightest 

 evolution of nitrous fumes. If this solution be now slowly dropped into 

 concentrated sulphuric acid cooled to — 10° C, the mixture becomes yellow 

 and pasty, from the formation of nitro-orcin, which is but slightly soluble 

 in sulphuric acid. When this is poured into a considerable quantity of 

 cold water, the nitro-body separates as a bright yellow crystalline powder, 

 quite free from any admixture of resin. 



After numerous experiments the following was found to be the most 

 advantageous process for the preparation of nitro-orcin. 6 grms. of 

 colourless orcin were dissolved in 6 cub. centims. of boiling water, and when 

 the solution had cooled to about 50° C, it was added in small portions at a 

 time, and with constant stirring, to 40 cub. centims. of nitric acid, sp. gr. 

 1*45, which was maintained at a temperature of about — 10° C. by immer- 

 sion in a good freezing-mixture. The solution, which was of a very pale 

 brown colour, was now added, in a similar manner, to 120 cub. centims. of 

 concentrated sulphuric acid, also maintained at —10° C. The pasty mass, 

 after being allowed to stand for fifteen or twenty minutes in the freezing- 

 mixture, was poured into a beaker containing 300 cub. centims. water and 

 400 grms. ice ; the crude nitro-compound was then precipitated as a yellow 

 or orange-coloured granular powder. The orcin employed in the prepara- 

 tion of this nitro-compound was colourless, having been purified by dis- 

 tillation in vacuo. The yield of crude nitro-orcin amounted to 150 per 

 cent, of the weight of the orcin. 



The crude nitro-orcin was collected, washed with a little cold water, 

 and purified by one or two crystallizations from boiling water (40 parts). 

 It was thus obtained in large yellow needles, which are readily soluble in 

 hot water and but slightly in the cold ; the addition of a strong acid preci- 

 pitates almost the whole of the nitro-orcin from its cold aqueous solution. 

 It is soluble in alcohol, very soluble in hot benzol, and crystallizes out in 

 great part on cooling ; it is less soluble in ether, and but moderately so in 

 bisulphide of carbon. It dyes the skin yellow, like picric acid, but is 

 tasteless. It volatilizes slightly at 100° C, melts at 162° C, and decom- 

 poses with slight explosion immediately afterwards. When heated with 

 concentrated sulphuric acid it dissolves, forming a deep yellow solution, 

 which deposits crystals on cooling, and is immediately precipitated by 

 water. It dissolves in hot strong nitric acid with evolution of nitrous 

 fumes and formation of oxalic acid. Like picric acid, when treated with 

 calcium hypochlorite it yields chloropicrin at the ordinary temperature. 

 Its aqueous solutions are coloured dark brown by ferric chloride, and com- 

 pletely precipitated by lead subacetate. 



The analysis of the substance dried at 100° C. was made, with the fol- 

 lowing results : — 



I. *335 grm. substance gave *400 grm. carbonic anhydride and *062 

 grm. water. 



