A Manual of the Chemistry of the Carbon Compounds

THE OABBON C0MF0U2W8, 343
dye-woods, with caustic potash; and it has also been produced by tbe
action of caustic potash upon benzenedisulphonic acid, paraphenolsnlphonio
acid, and para-iodophenol.
It forms colourless, triclinic crystals, melting at 99°, and boiling at
271°. It is very soluble in water, and possesses a sweetish and harsh
taste. Its aqueous solution is coloured dark violet by ferric salts.
When a solution of nitrous acid in nitric acid is added to a cold
and dilute etherial solution of resorcin, it is converted into diazoremcm
CjqH12N2CL dissolving in acetic acid with a dark cherry-red
colour, and crystallizing in small granular crystals, having a green,
metallic lustre.
By the action of hot sulphuric acid, or hydrochloric acid, this
compound is converted into diazoresorufin C^H^N.O,,, separating
from hot hydrochloric acid in small daricred and Irnllinnt granular
crystals. It dissolves in alkalis with a crimson colour; the dilute
solution exhibits a splendid vermilion-red fluorescence.
By heating diazoresorcin with acetyl chloride in sealed tubes, the
compound C^H^N.ClgO^ is formed, crystallizing from acetic acid in
yellow scales, ana dissolving in alkalis with a splendid violet colour.
Hot nitric acid converts it into the tetrazo-compouud C^HjgNj^LOg,,
crystallizing in small purple plates, the etlierial solution of which
shows a really surprising vermilion-red fluorescence.
( OH"
Mononitroresordn C6Hg(NO)2-j QTT is contained inconsiderable"
quantity in the mother-liquid from the preparation of diazoresorciu.
It crystallizes in very thin aud long, straw-coloured needles, and
forms three series of salts, the colour of which is lemon-yellow,
golden-yellow, and dark orange.
f OH
Trinitrore$orcin,ar StyphnicAcid C6H(NOg), •! QS, is obtained by
the action of nitric acid upon resorcin, and all resins and extracts
which yield resorcin on fusion with potash. It crystallizes in paleyellow
hexagonal prisms, and possesses a very astringent taste. Its
reddish-yellow salts crystallize well, and when heated explode even
more violently than the picrates.
TR1O.XV13ENZEKES.
roH
Pyrogallol, or Pyrogallic Add C6H3-< OH.—This body is framed
' (OH
when gallic acid CgHJOHJsCOjH is heated to 200°. It crystallizes
in shining white needles, and is readily soluble in water; the solution
has no acid reaction, and colours ferrous salts dark-blue, and ferric salts
red. By exposing an alkaline solution to the air, it rapidly absorbs
oxygen, and assumes a dark colour; it is therefore used to absorb