A Manual of the Chemistry of the Carbon Compounds

478 TEB CE£MISTRY OF
The most important of these is quinine, which always OCCUTS
together with cinchonine. The yellow bark (Cinchona Calysaya) contains
2 to 3 per cent of quinine, and 0'2 to 0-3 of cinchonine; while
the pale bark (Cinchona Condaminea) contains about 0*8 of quinine,
and 2 of cinchonine, and the red bark (Ciitch&na sucdrubra), about
2 of quinine and 1 of cinchonine.
Quinine C«HMNSO2 + HjO.-—For the preparation of this compound
the yellow or red bark is chiefly used. It is treated with
very dilute hydrochloric acid, and the solution is precipitated with
sodium carbonate. The precipitate is washed, and after being dried,
exhausted with boiling alcohol. The liquid is neutralized with
sulphuric acid, and the alcohol distilled off; from the residual liquid,
impure quinine sulphate crystallizes out, which is purified by dissolving
it again in alcohol, adding animal charcoal to decolorize the
solution, and crystallizing the sulphate by concentrating the liquid.
Ammonia precipitates quinine as a powder, which dissolves in
900 parts of cold water, and is tolerably soluble in ether, and freely in
alcohol, crystallizing from these solutions as a powder, and from
chloroform in distinct prisms.
Quinine is a tertiary base, and forma several series of salts, those
containing one equivalent of an acid are sparingly soluble in water,
while those containing more than one equivalent are readily soluble,
and form highly fluorescent solutions, the reflected light being of a
sky-blue colour. Quinine and its salts have an intensely bitter taste.
Basic Quinine Sulphate 2(CL0HMNaO2)SO4HB + 8H8O is manufactured
on a very large scale, and crystallizes in long brilliant
needles, which soon lose some water, and form a very light crystalline
powder. It dissolves in 780 parts of cold water, and more readily
in alcohol, and in boiling water.
Nernial Quinine Sulphate CJB.^fi^O^ + 7HSO is obtained by
dissolving the basic salt in dilute sulphuric aoid, and forma trans*
parent four-sided prisms, which dissolve in 11 parts of cold water.
AM Quiwitie Sulphate C^M^p^3B0^i% + 7H2O forms soft
white prisms, and is freely sohible in water; its solution exhibits a
splendid fluorescence.
When the basic sulphate is dissolved in acetio acid, and a solution
of iodine is added, large thin plates separate out, consisting of
CjoHg-NjCLSC^Hylj; they appear almost colourless by transmitted
light, but snow by reflection a brilliant emerald colour. This beautiful
compound possesses the optical properties of tuimaline, and is
used for optical experiments, under the name of fferapathite.
Basic Quinine Hydrockbride CjoH^NjOyClH + l^HjO crystallizes
in silky needles.
Normal QuinineHydrochlaride C^H^KgO^ClH), does not crystallize
well, and is decomposed by water into the basic salt and free acid. By
adding platinic chloride to its solution, the double salt C^H^NgOg
(C1H), + PtCl4 + HjO is obtained as a pale-yellow precipitate, which,
on standing, changes into orange-red crystals.