A Manual of the Chemistry of the Carbon Compounds

THE CARBON COMPOUNDS. 67
co 7
V
9
NHL, /
/ H CO
CO \
NH
Biuret is sparingly soluble in cold, but more readily iii hot water,
from which it crystallizes in colourless needles. On heuting it above
170°, ammonia escapes and cyanuric acid is left behind, and when it
is heated in a current of dry hydrochloric acid, carbon dioxide and
gnanidinc CHBN8 are formed, together with cyanuric acid:—
NH,
CO 7 Nfi3
NH a CO, + CO-NIt
Gunnidine is a stoong base, which will be described later on.
Isuretine CH4N2O.—This isomeride of \irea is produced by digestins
in alcoholic solution of hydroxylnmine with strong hydrocyanic
acid at 40°—50°. By evaporation it is obtained in long, colourless
crystals, having a strong alkaline reaction and melting at 104°. The
hydrochloride CH4NaO,HCl forms deliquescent rhombic plates; the
sulphate and oxalate are also crystallusable.
Heated above its melting-point isuietine readily decomposes, giving
a considerable sublimate of ammonium carbonate and yielding a residue
containing ammclidc (p. 61).
An aqueoxis solution of istiretine evaporated ou a watcv bath undergoes
decomposition with evolution of nitrogen, ammonia, and carbon
dioxide, and a residne is left containing urea and bmrtl. The constitution
of iauretine is probably expressed by one of the following
formula):—-
C fNH
C-^NILOH -^NI orC-Jo.NIL
IH I (H
Hydrmjl Carbamide COJ^Jj|^j is produced by acting upon
cyanic acid with hydroxylamine NH4(0H). To prepare it a solution
of hydroxylammouium nitrate is cooled down to - 10°, and mixed