A Manual of the Chemistry of the Carbon Compounds

408 TSB OHEMISTMT OF
powder, which is almost insoluble in water, and dissolves in alcohol
with a bluish-purple colour. If; is a powerful base, decomposing
ammonium salts, and absorbing readily carbon dioxide; its crystalline
salts exhibit a golden metallic lustre, and dissolve in water, and more
freely in alcohol, with a beautiful purple colour.
Mauveine HydrocMoride CWHJUN4.C1H crystallizes in small prisms,
and forms crystalliue double salts with the chlorides of gold and
platinum.
When mauve is heated with aniline, ammonia is given off, and a
blue colouring matter is formed, the composition of which is not
known.
Sy oxidizing a hot solution of mauve with sulphuric acid and manganese
dioxide, a beautiful red colouring-matter is produced, which is
very soluble in water, and forms small crystals having a line beetlegreen
lustre. In concentrated sulphuric acid it dissolves with a
dark-green colour, which, on adding gradually water in small quantities,
changes into bluish-green, pure blue, violet, purple, and at last into
pure Ted. To this beautiful substance the name " safranine" was
originally given, but the colour occurring now in commerce under
that name appears to be a different body.
Safranine CMHWN4.—This base is a derivative of pseudotoluidine,
and obtained by treating high-hoiliug commercial aniline with
nitrous acid and oxidizing agents. The free base is readily soluble in
water, and forms reddish-brown crystals, which, when heated to 100°,
assume a faint beetle-green lustre.
Safranine HydrocMoride Ct,HwN'4.ClH occurs in the forms of a
paste in commerce, and is largely used in dyeing silk, as a substitute
for safflower. It is very soluble in water, and precipitated from this
solution by adding salt; it has been obtained by evaporation in fine
reddish crystals. The nitrate is but sparingly soluble, and crystallizes
in reddish-brown needles. The picrate is insoluble in water, and
forms brown needles.
Safranine gives with sulphuric acid and water tiie same reactions as
mauve-safranine.
Azodiphmyl-blue C,gH,&N8 is obtained by heating anrido-azobeiizene
with aniline hydrochloriae and alcohol to 160°:—
Tiie free base is a dark-brown powder, which is insoluble in water.
The hydrochloride is a dark-blue, indistinctly crystalline body, dis*
solving in alcohol with a deep bluish.violet colour.
RO8ANIIJNE
The salts of this base are known by the names, Aniline-red,
Magenta, or Fttehsine, and manufactured in considerable quantity