A Manual of the Chemistry of the Carbon Compounds

268 THE 0HEMI8TRY OF
Dibroniopropyl Alcohol OjH6Br,j.OH boils at 219°; by the action of
nascent hydrogen it yields propyl alcohol, and on heating it with
caustic potash, glycerin is produced.
Monobromallyl Alcohol CjH^Br.OH.—When propenyl tribromide
is distilled with caustic potash, it is acted upon analogous to propenyl
trichloride (page 256), dibromw/lycide CH.Br— CBr=CH2 being
formed. By heating this body with an alcoholic solution of potassium
acetate it is converted into monobromallyl acetate, a liquid having a
refreshing smell and boiling at 164°. This ether is decomposed by
caustio alkalis, monobromallyl alcohol HO.CHS—CBr=CH2 being
produced, a mobile limpid liquid boiling at 155°, and possessing a
pleasant refreshing odour. Phosphorus pentachloride converts it iuto
monobromallyl chloride C8HJBrCl, a colourless heavy liquid boiling
at 120°.
Allyl Chloride CgH6Cl is a limpid liquid, boiling at 45°, which has
been prepared by heating allyl iodide with mercuric chloride aud
spirits of wine. It combines with chlorine to propenyl trichloride.
Allyl Bromide CgjHjBr is obtained by the action of phosphorus
bromide on allyl alcohol; it boils at 70°, and combines with bromine
to propenyl tribromide.
A llyl Iodide CSH5I may be produced by acting with iodine and
phosphorus npon allyl alcohol; but is more conveniently prepared
from glycerin. Six parts of iodine are placed into a retort, ten parts
of anhydrous glycerin poured on it, and three parts of phosphorus
are added, A violent reaction soon seta in, the mixture taking fire,
and allyl iodide distils; towards the end heat muat be applied to drive
the whole of the iodide over;—
C4H4(OH), + P +1 = CgHjT + PO3H8
On passing hydriodic acid gas iuto allyl iodide, the liquid becomes
hot, free iodine separates out, and isopropyl iodide is formed. In the
preparation of the latter compound from glycerin and hydriodic
ncid, first allyl iodide is formed, which by an excess of hydriodic acid
is further acted upon. If this acid be not present in excess, the
produot consists of a mixture of allyl iodide and isopropyl iodide:—
(I) C8H6(OH)8 + 3HI = OSH&1 + 3H,0 + I,
/o\ r* TT T i vytri r* tr T I T
By the action of clilorine upon allyl iodide, propenyl trichloride is
produced, whilst bromine converts it into propenyl tribromide.
When an alcoholio solution of allyl iodide is shaken with mercury,
mercury-aUyl iodide C3HfHgI is formed, which crystallizes from an
alcoholic solution ill shinutg scales. On heating with iodine it is again
converted into allyl iodide, whilst when heated by itself it yields
mercurous iodide and diallyl C6Hl0, a hydrocarbon which is also
formed by the action of sodium upon allyl iodide.