A Manual of the Chemistry of the Carbon Compounds

TUB CABBON COMPOUNDS. 465
weak nitric acid. It separates from an alcoholic solution iu yellow
needles or prisms, melting at 142°.
Dinitropyrene CjgHg^OJg is obtained when pyrene is toiled with
nitric acid of spec. grav. 1.45. It is insoluble in alcohol, and crystallizes
from acetic acid in slender yellow needles.
Tetmnitropyraie CJ8H8(NOJ)4 is formed by the action of boiling
concentrated nitric acid on dinitropyiene, and crystallizes from acetic
acid in glistening plates or needles.
Bromine-derivatives,—When pyrene comes in contact witli cold
bromine-vapour, it is converted into dibromopyrene dibromide
CLHaBr^ which crystallizes from nitrobenzene in pale yellow needles,
Trbromojn/rene GieELiBTa is formed by the action of bromine on a
solution of pyrene in carbou disulphide; it is almost insoluble in
alcohol, ether, and carbon disulphide; from boiling nitrobenzene it
crystallizes in colourless needles.
Pyroqwium G^R^if?—To prepare fchis compound, pyrene is dis-
. solved in glacial acetic acid, and solid chromic trioxide is added to
the solution. It crystallizes in red needles or prisms, dissolving in
concentrated sulphuric acid with a brown colour. Bed-hot zinc-dust
reduces it like other quinones; the hydrogen required for this reduction
being furnished by zinc hydroxide, which is always present:—
0wF8Os + 3Zn + Zn(0H)2 = CwH10 + 4ZnO
CHRYSENE
On exhausting fche yellow body, which has been mentioned under
pyrene, with carbon, disulphide, ft granular powder, resembling flowers
of sulphur, and consisting of impure chrysene, is left behind. It is
but sparingly soluble in the common solvents, and crystallizes from
boiling alcohol i& rhombic plates, melting at 250°. "With picric acid
it forms a compound, crystallizing front benzene in brownish-orange
needles.
Nitroehrysmc C,8Hu.E'Oj is slowly formed when chrysene is boiled
with absolute alcohol and nitric acid; it forma orange crystals.
Tetranitwrhrysene C,?H8(NO2)4 is obtained by dissolving the hydrocarbon
in fuming nitric acid as a yellow powder, which is only
sparingly soluble in most solvents.
Chrysoquinone C18H,00"8 is produced by the action of chromic trioxide
on a solution of chrysene in acetic acid. It crystallizes from
hot alcohol in red rhombic prisms or plates, dissolving in strong sulphuric
acid with a splendid bhie colour. On boiling it with potash
and zinc-diist, a yellow solution is formed, from which acids precipitate
ehrysohydroguinone C18H1O(OH), in nearly colourless flakes; it in
easily oxidized again to the quinone.